Contact device

Technical Field

0001The present invention is directed to contact devices, and more particularly to a contact device suitable for a relay or electromagnetic switch for power loads.

Background Art

0002As shown in <figref idref="f0020">FIG. 25A</figref>, a prior contact device <b>1000</b> includes a sealed receptacle <b>1100</b> (see Japanese patent laid-open publication No. <patcit id="pcit0001" dnum="JP10326530A"><text>10-326530</text></patcit>). In the following explanation, an upper direction in <figref idref="f0020">FIG. 25A</figref> denotes a forward direction of the contact device <b>1000,</b> and a lower direction in <figref idref="f0020">FIG. 25A</figref> denotes a rearward direction of the contact device <b>1000.</b>

0003The sealed receptacle <b>1100</b> includes a contact case <b>1110</b> made of dielectric materials, a cylindrical member <b>1120</b> made of metals, and a closure plate <b>1130.</b> The contact case <b>1110</b> is provided in its rear wall with an aperture <b>1111.</b> The cylindrical member <b>1120</b> has its front end secured in an airtight manner to a periphery of the aperture <b>1111</b> of the contact case <b>1110.</b> The closure plate <b>1130</b> is secured in an airtight manner to a rear end of the cylindrical member <b>1120.</b> The sealed receptacle <b>1100</b> houses fixed contacts <b>1200</b> and a movable contact <b>1300.</b>

0004The contact device <b>1000</b> further includes a drive device <b>1500</b> having a shaft <b>1400.</b> The shaft <b>1400</b> has its front end attached to a holding case <b>1600.</b> The holding case <b>1600</b> holds the movable contact <b>1300</b> movably along the forward/rearward direction. In addition, the holding case <b>1600</b> accommodates a contact pressure provision spring <b>1700.</b> The contact pressure provision spring <b>1700</b> biases the movable contact <b>1300</b> forward such that the movable contact <b>1300</b> comes into contact with the fixed contacts <b>1200</b> at a desired contact pressure. The drive device <b>1500</b> moves forward/rearward the shaft <b>1400</b> by use of an electric magnet. The movable contact <b>1300</b> is kept away from the fixed contacts <b>1200</b> when the shaft <b>1400</b> is moved rearward by a predetermined distance. The movable contact <b>1300</b> comes into contact with the fixed contacts <b>1200</b> when the shaft <b>1400</b> is moved forward by a predetermined distance.

0005The sealed receptacle <b>1100</b> further houses an arc protection member <b>1140.</b> As shown in <figref idref="f0020">FIG. 25B</figref>, the arc protection member <b>1140</b> includes a peripheral wall <b>1141</b> shaped into a cylindrical shape and a flange <b>1142.</b> The peripheral wall <b>1141</b> is configured to conceal a junction between the contact case <b>1110</b> and the cylindrical member <b>1120</b> from the fixed contacts <b>1200</b> and the movable contact <b>1300.</b> The arc protection member <b>1140</b> is pressed forward by pressing springs <b>11150</b> such that the flange <b>1142</b> comes into contact with the cylindrical member <b>1120.</b> Thereby, the arc protection member <b>1140</b> is held in a predetermined position in the sealed receptacle <b>1100.</b>

0006As apparent from the above, the prior contact device <b>1000</b> needs the pressing spring <b>1150</b> to hold the arc protection member <b>1140.</b><patcit id="pcit0002" dnum="EP1168392A1"><text>EP 1 168 392 A1</text></patcit> discloses a contact apparatus including a permanent magnet being disposed in a region where a fixing contact point mounted to the fixing contact and a movable contact to which the movable contact point is mounted. An arc-extinguishing member for generating arc-extinguishing gas is provided such as to surround the fixing contact point and the movable contact point.

Disclosure of Invention

0007In view of the above insufficiency, the present invention has been aimed to propose a contact device capable of reducing the number of parts necessitated for holding the arc protection member and reducing its production cost.

0008The contact device in accordance with the present invention is defined in claim 1.

0009In a preferred embodiment, the drive unit includes a shaft and an actuator. The shaft is disposed so as to penetrate through the movable contact, the bottom of the arc protection member, and the closure plate. The shaft is provided at its first end inside the sealed receptacle with a latch coming into contact with a fixed contact side surface of the movable contact. The shaft has its second end outside the sealed receptacle coupled to the actuator. The actuator is configured to move the shaft along its axial direction between a position where the latch separates the movable contact from the fixed contact and a position where the latch allows the movable contact to come into contact with the fixed contact. The sealed receptacle is configured to house a dust prevention member configured to cover a clearance between the shaft and a periphery of a through hole for the shaft formed in the bottom of the arc protection member. The dust prevention member includes a flange portion interposed between the contact pressure provision member and the bottom of the arc protection member.

0010In this preferred embodiment, it is possible to prevent dust from passing through the through hole of the arc protection member. Further, the dust prevention member is held by the contact pressure provision member. Therefore, it is unnecessary to add special parts for holding the dust prevention member. For example, the aforementioned dust is dissipation particles generated by contact of the movable contact with the fixed contact or by separation of the movable contact from the fixed contact.

0011In a preferred embodiment, any one of the closure plate and the bottom of the arc protection member includes a protrusion for positioning with the other including a recess for positioning configured to receive the positioning protrusion.

0012In this preferred embodiment, the arc protection member can be easily assembled into the contact device.

0013In a preferred embodiment, the drive unit includes a shaft, and an actuator including a fixed core penetrating through the closure plate, a movable core, and an electromagnet device. The shaft is disposed to penetrate through the movable contact, the bottom of the arc protection member, and the fixed core. The shaft is provided at its first end inside the sealed receptacle with a latch coming into contact with a fixed contact side surface of the movable contact. The shaft has its second end outside the sealed receptacle secured to the movable core. The electromagnet device is configured to generate a magnetic attraction between the fixed core and the movable core. The actuator is configured to control the electromagnet device to move the shaft along its axial direction between a position where the latch separates the movable contact from the fixed contact and a position where the latch allows the movable contact to come into contact with the fixed contact. The contact device includes a cap configured to fix the fixed core to the closure plate. The cap is secured to a surface of the closure plate opposed to the bottom of the arc protection member. Any one of the cap and the bottom of the arc protection member includes a protrusion for positioning with the other including a recess for positioning configured to receive the positioning protrusion.

0014In this preferred embodiment, the arc protection member can be easily assembled into the contact device.

0015In a more preferred embodiment, the contact device includes a plurality of the protrusions for positioning and a plurality of the recesses for positioning respectively corresponding to the plurality of the protrusions for positioning.

0016In this preferred embodiment, the arc protection member can be positioned while being prevented from rotating. Therefore, the arc protection member can be mounted yet without requiring adjusting a deviation caused by a rotation of the arc protection member. Thus, the contact device can be easily assembled. In addition, it is possible to reduce the production cost.

0017In a preferred embodiment, the drive unit includes a shaft, and an actuator including a fixed core penetrating through the closure plate, a movable core, and an electromagnet device. The shaft is disposed to penetrate through the movable contact, the bottom of the arc protection member, and the fixed core. The shaft is provided at its first end inside the sealed receptacle with a latch coming into contact with a fixed contact side surface of the movable contact. The shaft has its second end outside the sealed receptacle secured to the movable core. The electromagnet device is configured to generate a magnetic attraction between the fixed core and the movable core. The actuator is configured to control the electromagnet device to move the shaft along its axial direction between a position where the latch separates the movable contact from the fixed contact and a position where the latch allows the movable contact to come into contact with the fixed contact. The contact device includes a cap configured to fix the fixed core to the closure plate, the cap being secured to a surface of the closure plate opposed to the bottom of the arc protection member. The closure plate is provided with a first protrusion for positioning. The cap is provided with a second protrusion for positioning. The arc protection member is provided in its bottom with a first recess for positioning configured to receive the first protrusion and the second recess for positioning configured to receive a second protrusion.

0018In this situation, it is possible to position the arc protection member without rotating. Therefore, the arc protection member can be mounted yet without requiring adjusting a deviation caused by a rotation of the arc protection member. Thus, the contact device can be easily assembled. In addition, it is possible to reduce the production cost.

0019In a preferred embodiment, the bottom of the arc protection member has a positioning portion configured to surround the contact pressure provision member.

0020In this preferred embodiment, the contact pressure provision member can be easily attached to the arc protection member.

0021In a more preferred embodiment, the positioning portion has its inner surface inclined such that a distance between the inner surface and the contact pressure provision member increases as a distance from the bottom increases.

0022In this preferred embodiment, the inner surface of the positioning portion guides the contact pressure provision member to an inside of the positioning portion. Therefore, the contact pressure provision member can be more easily attached to the arc protection member.

0023In a preferred embodiment, the contact pressure provision member is a coil spring. The arc protection member is provided on its bottom with a positioning portion configured to intrude into the contact pressure provision member.

0024In this preferred embodiment, the contact pressure provision member can be easily attached to the arc protection member.

0025In a more preferred embodiment, the positioning portion has its outer surface inclined such that a distance between the outer surface and the contact pressure provision member increases as a distance from the bottom increases.

0026In this preferred embodiment, the outer surface of the positioning portion guides the contact pressure provision member to the inside of the positioning portion. Therefore, the contact pressure provision member can be more easily attached to the arc protection member.

Brief Description of Drawings

0027<ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">FIG. 1</figref> is a cross sectional view illustrating a primary part of a contact device of a first embodiment in accordance with the present invention,</li><li><figref idref="f0002">FIG. 2A</figref> is an exploded perspective view illustrating the above contact device,</li><li><figref idref="f0002">FIG. 2B</figref> is a perspective view illustrating a cover of the above contact device,</li><li><figref idref="f0003">FIG. 3A</figref> is a cross sectional view illustrating an arc protection member of the above contact device,</li><li><figref idref="f0003">FIG. 3B</figref> is a cross sectional view illustrating the arc protection member of the above contact device,</li><li><figref idref="f0003">FIG. 4</figref> is an explanatory view illustrating the arc protection member and a closure plate of the above contact device,</li><li><figref idref="f0004">FIG. 5</figref> is a perspective view illustrating a dust prevention member of the above contact device,</li><li><figref idref="f0004">FIG. 6A</figref> is a cross sectional view illustrating a shock absorber of the above contact device,</li><li><figref idref="f0004">FIG. 6B</figref> is a bottom view illustrating the shock absorber of the above contact device,</li><li><figref idref="f0005">FIG. 7A</figref> is an explanatory view illustrating a method of attaching the shock absorber to a fixed core of the above contact device,</li><li><figref idref="f0005">FIG. 7B</figref> is an explanatory view illustrating the method of attaching the shock absorber to the fixed core of the above contact device,</li><li><figref idref="f0005">FIG. 8A</figref> is a cross sectional view illustrating a modification of the arc protection member of the contact device,</li><li><figref idref="f0005">FIG. 8B</figref> is a cross sectional view illustrating the modification of the arc protection member of the contact device of <figref idref="f0005">FIG. 8A</figref>,</li><li><figref idref="f0006">FIG. 9A</figref> is a front view illustrating an extinguishing unit of the above contact device,</li><li><figref idref="f0006">FIG. 9B</figref> is a left side view illustrating the extinguishing unit of the above contact device,</li><li><figref idref="f0007">FIG. 10A</figref> is a top view illustrating a base of the above contact device,</li><li><figref idref="f0007">FIG. 10B</figref> is a cross sectional view of the base of the above contact device along the line A-A',</li><li><figref idref="f0008">FIG. 11</figref> is a right side view illustrating the base and a contacts mechanism unit of the above contact device,</li><li><figref idref="f0008">FIG. 12</figref> is an explanatory view illustrating a method of attaching the extinguishing unit to the base of the above contact device,</li><li><figref idref="f0009">FIG. 13A</figref> is a right side view illustrating the above contact device without the cover,</li><li><figref idref="f0009">FIG. 13B</figref> is a front view illustrating the above contact device without the cover,</li><li><figref idref="f0010">FIG. 14A</figref> is a cross sectional view illustrating a primary part of a modification of the above contact device,</li><li><figref idref="f0010">FIG. 14B</figref> is a cross sectional view illustrating the primary part of the modification of the above contact device of <figref idref="f0010">FIG. 14A</figref>,</li><li><figref idref="f0010">FIG. 14C</figref> is a cross sectional view illustrating a primary part of a modification of the above contact device,</li><li><figref idref="f0010">FIG. 14D</figref> is a cross sectional view illustrating the primary part of the modification of the above contact device of <figref idref="f0010">FIG. 14C</figref>,</li><li><figref idref="f0011">FIG. 15A</figref> is an explanatory view illustrating a modification of the above contact device,</li><li><figref idref="f0011">FIG. 15B</figref> is an explanatory view illustrating a modification of the above contact device,</li><li><figref idref="f0011">FIG. 15C</figref> is an explanatory view illustrating a modification of the above contact device,</li><li><figref idref="f0012">FIG. 16A</figref> is a rear view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0012">FIG. 16B</figref> is a perspective view illustrating the modification of the shock absorber of the above contact device of the <figref idref="f0012">FIG. 16A</figref>,</li><li><figref idref="f0012">FIG. 16C</figref> is a rear view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0012">FIG. 16D</figref> is a perspective view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0012">FIG. 16C</figref>,</li><li><figref idref="f0012">FIG. 16E</figref> is a rear view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0012">FIG. 16F</figref> is a perspective view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0012">FIG. 16E</figref>,</li><li><figref idref="f0013">FIG. 17A</figref> is a cross sectional view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0013">FIG. 17B</figref> is a front view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0013">FIG 17A</figref>,</li><li><figref idref="f0013">FIG. 17C</figref> is a rear view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0013">FIG. 17A</figref>,</li><li><figref idref="f0013">FIG. 17D</figref> is a cross sectional view illustrating a situation where the modification of the shock absorber of the above contact device of <figref idref="f0013">FIG. 17A</figref> is attached to the fixed core,</li><li><figref idref="f0014">FIG. 18A</figref> is a cross sectional view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0014">FIG. 18B</figref> is a front view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0014">FIG. 18A</figref>,</li><li><figref idref="f0014">FIG. 18C</figref> is a rear view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0014">FIG. 18A</figref>,</li><li><figref idref="f0015">FIG. 19A</figref> is a cross sectional view illustrating a modification of the shock absorber of the above contact device,</li><li><figref idref="f0015">FIG. 19B</figref> is a front view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0015">FIG. 19A</figref>,</li><li><figref idref="f0015">FIG. 19C</figref> is a rear view illustrating the modification of the shock absorber of the above contact device of <figref idref="f0015">FIG. 19A</figref>,</li><li><figref idref="f0015">FIG. 19D</figref> is a cross sectional view illustrating a situation where the modification of the shock absorber of the above contact device of <figref idref="f0015">FIG. 19A</figref> is attached to the fixed core,</li><li><figref idref="f0016">FIG. 20A</figref> is a schematic view illustrating a modification of the above contact device,</li><li><figref idref="f0016">FIG. 20B</figref> is an enlarged view illustrating the modification of the above contact device of <figref idref="f0016">FIG. 20A</figref>,</li><li><figref idref="f0016">FIG. 21A</figref> is an explanatory view illustrating a method of attaching an external connection terminal to a fixed terminal of the modification of the above contact device of <figref idref="f0016">FIG. 20A</figref>,</li><li><figref idref="f0016">FIG. 21B</figref> is an explanatory view illustrating the method of attaching the external connection terminal to the fixed terminal of the modification of the above contact device of <figref idref="f0016">FIG. 20A</figref>,</li><li><figref idref="f0017">FIG. 22A</figref> is an explanatory view illustrating a method of attaching the external connection terminal to the fixed terminal of a modification the above contact device,</li><li><figref idref="f0017">FIG. 22B</figref> is an explanatory view illustrating the method of attaching the external connection terminal to the fixed terminal of the modification the above contact device of <figref idref="f0017">FIG. 22A</figref>,</li><li><figref idref="f0017">FIG. 22C</figref> is an explanatory view illustrating the method of attaching the external connection terminal to the fixed terminal of the modification the above contact device of <figref idref="f0017">FIG. 22A</figref>,</li><li><figref idref="f0017">FIG. 22D</figref> is a perspective view illustrating a modification of the external connection terminal of the above contact device,</li><li><figref idref="f0018">FIG. 23A</figref> is a partial plan view illustrating a modification of the external connection terminal of the above contact device,</li><li><figref idref="f0018">FIG. 23B</figref> is a partial plan view illustrating a modification of the external connection terminal of the above contact device,</li><li><figref idref="f0018">FIG. 23C</figref> is a partial plan view illustrating a modification of the external connection terminal of the above contact device,</li><li><figref idref="f0018">FIG. 23D</figref> is a partial plan view illustrating a modification of the external connection terminal of the above contact device,</li><li><figref idref="f0019">FIG. 24A</figref> is an explanatory view illustrating a method of attaching the external connection terminal to the fixed terminal of a modification the above contact device,</li><li><figref idref="f0019">FIG. 24B</figref> is an explanatory view illustrating the method of attaching the external connection terminal to the fixed terminal of the modification the above contact device of <figref idref="f0019">FIG. 24A</figref>,</li><li><figref idref="f0019">FIG. 24C</figref> is a perspective view illustrating the modification of the external connection terminal of the above contact device of <figref idref="f0017">FIG. 22D</figref>,</li><li><figref idref="f0020">FIG. 25A</figref> is a cross sectional view illustrating a prior contact device, and</li><li><figref idref="f0020">FIG. 25B</figref> is a perspective view illustrating an arc protection member and pressing springs of the prior contact device.</li></ul>

Best Mode for Carrying Out the Invention

0028The contact device <b>10</b> of an embodiment in accordance with the present invention is so-called a sealed contact device (or so-called a silent contact device). As shown in <figref idref="f0002">FIGS. 2A and 2B</figref>, the contact device <b>10</b> includes a contacts mechanism unit <b>11,</b> an extinguishing unit <b>12,</b> and a housing <b>13</b> configured to house the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12.</b> In a following explanation, an upward direction in <figref idref="f0001">FIG. 1</figref> denotes a forward direction of the contact device <b>10,</b> and a downward direction in <figref idref="f0001">FIG. 1</figref> denotes a rearward direction of the contact device <b>10</b>, and a left direction in <figref idref="f0001">FIG. 1</figref> denotes a left direction of the contact device <b>10</b>, and a right direction in <figref idref="f0001">FIG. 1</figref> denotes a right direction of the contact device <b>10</b>. In addition, an upward direction in <figref idref="f0002">FIG. 2A</figref> denotes an upward direction of the contact device <b>10</b>, and a downward direction in <figref idref="f0002">FIG. 2A</figref> denotes a downward direction of the contact device <b>10</b>.

0029As shown in <figref idref="f0001">FIG. 1</figref>, the contacts mechanism unit <b>11</b> includes a sealed receptacle <b>20</b> configured to house a fixed contact <b>31</b>, a movable contact <b>40</b>, and an arc protection member <b>60</b>, and a drive unit <b>50.</b>

0030The drive unit <b>50</b> is configured to move the movable contact <b>40</b> between an on-position and an off-position. The on-position is defined as a position where the movable contact <b>40</b> is kept in contact with the fixed contact <b>31</b>. The off-position is defined as a position where the movable contact <b>40</b> is kept away from the fixed contact <b>31</b>. The aforementioned drive unit <b>50</b> includes a contact pressure provision spring (contact pressure provision member) <b>51</b>, a fixed core <b>52</b>, a shaft <b>53</b>, a movable core <b>54</b>, a return spring <b>55</b>, and an electromagnet device <b>56</b>. In this drive unit <b>50</b>, the fixed core <b>52</b>, the movable core <b>54</b>, and the electromagnet device <b>56</b> constitute an actuator configured to move the shaft <b>53</b> along its axial direction.

0031The sealed receptacle <b>20</b> includes a case (contact case) <b>21</b> made of dielectric materials, a cylindrical member <b>22</b> made of metals, and a closure plate <b>23</b>.

0032The case <b>21</b> is provided with an aperture <b>211</b> in its rear wall (first wall). The case <b>21</b> is provided with two through holes <b>212</b> for fixed terminals <b>30</b> in a right portion and left portion of its front wall (second wall opposed to the first wall). The dielectric material of the case <b>21</b> is preferred to be a ceramic having heat resistance.

0033The cylindrical member <b>22</b> is defined as a junction member for connecting the closure plate <b>23</b> to the case <b>21</b>. The cylindrical member <b>22</b> is shaped into a cylindrical shape. An axial center portion of the cylindrical member <b>22</b> is wholly bent to narrow its front aperture relative to its rear aperture.

0034The closure plate <b>23</b> is made of magnetic metals (e.g. irons) and is shaped to have a rectangular shape. The closure plate <b>23</b> has enough dimensions to cover the rear aperture of the cylindrical member <b>22</b>. The closure plate <b>23</b> is provided with a recess <b>231</b> in a center of its front surface. A through hole <b>232</b> for the fixed core <b>52</b> is formed in a center of a bottom of the recess <b>231</b>. Further, a cap <b>24</b> and a core case <b>25</b> are fixed to the closure plate <b>23</b>.

0035In respect to the sealed receptacle <b>20</b>, the cylindrical member <b>22</b> has its front end (first axial end) secured in an airtight manner to a periphery of the aperture <b>211</b> of the rear wall of the case <b>21</b>. The cylindrical member <b>22</b> further has its rear end (second axial end) secured in an airtight manner to the closure plate <b>23</b>. An extinguishing gas (e.g. hydrogen gas) is sealed in the sealed receptacle <b>20</b>.

0036The fixed terminals <b>30</b> are secured to the front wall of the sealed receptacle <b>20</b>. The fixed terminal <b>30</b> is made of metals (e.g. a copper material) and is shaped into a circular cylindrical shape. The fixed contact <b>31</b> is secured to a rear end (first end) of the fixed terminal <b>30</b>. The fixed contact <b>31</b> is attached to the front wall of the sealed receptacle <b>20</b> through the fixed terminal <b>30</b>. The fixed terminal <b>30</b> is provided with a flange <b>32</b> at its front end (second end) and is provided with a screw hole <b>33</b> in its front end. In the present embodiment, the fixed terminal <b>30</b> and the fixed contact <b>31</b> are provided as separate parts. However, a part of the fixed terminal <b>30</b> may be defined as the fixed contact <b>31</b>.

0037The front end of the fixed terminal <b>30</b> extends out through the through hole <b>212</b> from the sealed receptacle <b>20</b>. In other words, the fixed terminal <b>30</b> is attached to the sealed receptacle <b>20</b> to place its rear end inside the sealed receptacle <b>20</b> and to place its front end outside the sealed receptacle <b>20</b>. In this situation, the flange <b>32</b> of the fixed terminal <b>30</b> is fixed in an airtight manner to the front wall of the case <b>21</b>, by use of a brazing method or the like. The screw hole <b>33</b> of the fixed terminal <b>30</b> is used for fixing an external connection terminal <b>34</b> (see <figref idref="f0002">FIG. 2</figref>) to the fixed terminal <b>30</b> by use of a screw. The external connection terminal <b>34</b> is used for connection of the fixed contact <b>31</b> and an external circuit (e.g. an electrical circuit of a mounted board on which the contact device <b>10</b> is mounted).

0038The movable contact <b>40</b> is made of metals (e.g. a copper material) and is shaped into a rectangular plate shape. The movable contact <b>40</b> has enough dimensions to come into contact with both the right and left fixed contacts <b>31</b>. In the present embodiment, right and left portions of the movable contact <b>40</b> are respectively defined as a contact portion <b>41</b> for the fixed contact <b>31</b>. The movable contact <b>40</b> further has a through hole <b>42</b> for a shaft. The through hole <b>42</b> penetrates through a center of the movable contact <b>40</b> along a thickness direction of the movable contact <b>40</b>. In the present embodiment, a part of the movable contact <b>40</b> is used as the contact portion <b>41</b>. However, the contact portion <b>41</b> may be provided as a separate part from the movable contact <b>40</b>.

0039As shown in <figref idref="f0003">FIGS. 3A and 3B</figref>, the arc protection member <b>60</b> includes a cylindrical peripheral wall <b>61</b> and a bottom <b>62</b>. The peripheral wall <b>61</b> is configured to conceal a junction between the case <b>21</b> and the cylindrical member <b>22</b> from the fixed contacts <b>31</b> and the movable contact <b>40</b>. The bottom <b>62</b> is configured to cover a rear aperture of the peripheral wall <b>61</b>. The bottom <b>62</b> is interposed between the movable contact 40 and the closure plate <b>23</b>. The bottom <b>62</b> is provided in its center with a through hole <b>63</b> for a shaft <b>53</b>.

0040The contact pressure provision spring (hereinafter abbreviated as "spring") <b>51</b> is a coil spring. The spring <b>51</b> is interposed between the bottom <b>62</b> of the arc protection member <b>60</b> and the movable contact <b>40</b>. The spring <b>51</b> has its natural length to be always compressed irrespective of a position of the movable contact <b>40</b>. That is, the spring <b>51</b> is interposed between the movable contact <b>40</b> and the bottom <b>62</b> of the arc protection member <b>60</b> so as to come into resilient contact with both the movable contact <b>40</b> and the bottom <b>62</b> of the arc protection member <b>60</b> irrespective of a position of the movable contact <b>40</b>. The spring <b>51</b> is not limited to a coil spring and may be a plate spring. An elastic member (e.g. a rubber) can be adopted as the contact pressure provision member instead of the spring <b>51</b>.

0041By the way, as shown in <figref idref="f0003">FIG. 4</figref>, the bottom <b>62</b> is provided with a recess <b>64</b> for positioning in its rear surface (surface of the bottom <b>62</b> opposed to the closure plate <b>23</b>). The recess <b>64</b> is formed in the rear surface of the bottom <b>62</b> so as to receive a nipper portion <b>241</b> of an after-mentioned cap <b>24</b> when the arc protection member <b>60</b> is placed in a predetermined position relative to the closure plate <b>23</b>.

0042Meanwhile, the bottom <b>62</b> is provided in its front surface (surface of the bottom <b>62</b> opposed to the movable contact <b>40</b>) with a positioning portion <b>65</b> for the spring <b>51</b>. The positioning portion <b>65</b> is shaped into a circular cylindrical shape to surround a rear end (end of the spring <b>51</b> which comes into contact with the bottom 6<b>2</b>) of the spring <b>51</b>. The positioning portion <b>65</b> further has its inner surface inclined such that a distance between the inner surface and the spring <b>51</b> increases as a distance from the bottom <b>62</b> increases (the distance between the inner surface and the spring <b>51</b> is made greater towards a front end of the positioning portion <b>65</b> than at a rear end of the positioning portion <b>65</b>). In other words, the positioning portion <b>65</b> has a tapered shape to guide the rear end of the spring <b>51</b> to an inside of the positioning portion <b>65</b>. The positioning portion <b>65</b> is not always required to have a cylindrical shape. The positioning portion <b>65</b> may be defined by a plurality of protrusions arranged to surround the rear end of the spring <b>51</b>.

0043A dust prevention member <b>26</b> is located inside the positioning portion <b>65</b>. The dust prevention member <b>26</b> is configured to cover a clearance between the shaft <b>53</b> and a periphery of the through hole <b>63</b> of the arc protection member <b>60</b>. The dust prevention member <b>26</b> is made of an elastic material (e.g. an elastomer such as a silicone rubber). As shown in <figref idref="f0004">FIG. 5</figref>, the dust prevention member <b>26</b> has a cylindrical portion <b>261</b> shaped into a circular cylindrical shape. The cylindrical portion <b>261</b> has its inner diameter greater than an inner diameter of the through hole 63<b>.</b> The dust prevention member <b>26</b> has a front wall portion <b>262</b> covering a front aperture of the cylindrical portion <b>261</b>. The front wall portion <b>262</b> is provided in its center with a hole <b>263</b>. The hole <b>263</b> has its inner diameter slightly smaller than an outer diameter of the shaft <b>53</b>. Consequently, an inner periphery of the hole <b>263</b> comes into close contact with an outer periphery of the shaft <b>53</b>. The front wall portion <b>262</b> is formed to have its peripheral portion of the hole <b>263</b> thicker than its outer edge portion. Accordingly, it is possible to improve contact of the inner periphery of the hole <b>263</b> and the outer periphery of the shaft <b>53</b>. The dust prevention member <b>26</b> further has a flange portion <b>264</b>. The flange portion <b>264</b> extends out from the rear end of the cylindrical portion <b>261</b>. As shown in <figref idref="f0003">FIG. 3B</figref>, the flange portion <b>264</b> is interposed between the rear end of the spring <b>51</b> and the bottom <b>62</b>. That is, the flange portion <b>264</b> of the dust prevention member <b>26</b> is held by the spring <b>51</b> and the bottom <b>62</b> between the spring <b>51</b> and the bottom <b>62</b>. Thereby, the dust prevention member <b>26</b> is fixed to the arc protection member <b>60</b>.

0044The fixed core <b>52</b> is made of a magnetic material and is shaped into a cylindrical shape (e.g. a circular cylindrical shape). The fixed core <b>52</b> is provided at its front end with a flange <b>521</b> configured to be hooked over a periphery of the through hole <b>232</b> of the closure plate <b>23</b>.

0045The aforementioned cap <b>24</b> is used for fixing the fixed core <b>52</b> to the closure plate <b>23</b>. The cap <b>24</b> includes the nipper portion <b>241</b> being in the form of a rectangular plate shape and configured to hold the flange <b>521</b> of the fixed core <b>52</b> in association with the closure plate <b>23</b>. The nipper portion <b>241</b> is defined as a protrusion for positioning corresponding to the recess <b>64</b> of the arc protection member <b>60</b>. Fixing portions <b>242</b> are provided to right and left ends of a rear surface of the nipper portion <b>241</b>, respectively. The cap <b>24</b> is fixed to the closure plate <b>23</b> by bonding rear surfaces of the fixing portions <b>242</b> to the front surface of the closure plate <b>23</b>. The nipper portion <b>241</b> is further provided with a through hole <b>243</b> for the shaft <b>53</b>. The through hole <b>243</b> has its inner diameter smaller than an inner diameter of the fixed core <b>52</b>.

0046The front end of the fixed core <b>52</b> is covered with a shock absorber <b>58</b>. The shock absorber <b>58</b> is made of an elastic material (e.g. an elastomer such as a silicone rubber). As shown in <figref idref="f0004">FIGS. 6A and 6B</figref>, the shock absorber <b>58</b> includes a first resilient portion <b>581</b> and a second resilient portion <b>582</b>. The first resilient portion <b>581</b> is interposed between the flange <b>521</b> of the fixed core <b>52</b> and the nipper portion <b>241</b> of the cap <b>24</b>. The second resilient portion <b>582</b> is interposed between the flange <b>521</b> of the fixed core <b>52</b> and the closure plate <b>23</b>. Both the first resilient portion <b>581</b> and the second resilient portion <b>582</b> are in the form of a circular disk shape. The first resilient portion <b>581</b> is provided in its center with a through hole <b>583</b> for the shaft <b>53</b>. The second resilient portion <b>582</b> is provided in its center with a through hole <b>584</b> for the fixed core <b>52</b>.

0047Additionally, the shock absorber <b>58</b> includes a connection portion <b>585</b> configured to integrally connect an outer edge of the first resilient portion <b>581</b> to an outer edge of the second resilient portion <b>582</b>. It is noted that a distance between a rear surface of the first resilient portion <b>581</b> and a front surface of the second resilient portion <b>582</b> is identical to a thickness of the flange <b>521</b> of the fixed core <b>52</b>.

0048The shock absorber <b>58</b> is attached to the fixed core <b>52</b> as follows. As shown in <figref idref="f0005">FIGS. 7A and 7B</figref>, the flange <b>521</b> of the fixed core <b>52</b> is inserted into the shock absorber <b>58</b> via the through hole <b>584</b>. In order to attach the shock absorber <b>58</b> to the fixed core <b>52</b>, the second resilient portion <b>582</b> is elastically deformed such that the inner diameter of the through hole <b>584</b> becomes greater than the outer diameter of the flange <b>521</b>.

0049In the prior contact device, the shock absorber <b>58</b> includes the first resilient portion <b>581</b> and the second resilient portion <b>582</b>. However, in the prior contact device, the first resilient portion <b>581</b> is separated from the second resilient portion <b>582</b>. Therefore, in order to attach the shock absorber <b>58</b> to the fixed core <b>52</b>, it is necessary to attach the first resilient portion <b>581</b> to the front surface side of the flange <b>521</b> and also to attach the second resilient portion <b>582</b> to the rear surface side of the flange <b>522</b>. Additionally, it is difficult to manipulate the first resilient portion <b>581</b> and the second resilient portion <b>582</b> individually. Therefore, the shock absorber <b>58</b> can not be easily attached to the fixed core <b>52</b>.

0050However, in the contact device <b>10</b> of the present embodiment, the shock absorber <b>58</b> includes the connection portion <b>585</b> configured to integrally connect the first resilient portion <b>581</b> to the second resilient portion <b>582</b>. Therefore, it is unnecessary to attach individually the first resilient portion <b>581</b> and the second resilient portion <b>582</b> to the fixed core <b>52</b>. In addition, it is easy to manipulate the shock absorber <b>58</b>. Thus, the shock absorber <b>58</b> can be easily attached to the fixed core <b>52</b>.

0051The core case <b>25</b> is configured to house the fixed core <b>52</b> in its front end side and the movable core <b>54</b> in its rear end side. The core case <b>25</b> includes a side wall portion <b>251</b> shaped into a circular cylindrical shape. The side wall portion <b>251</b> has its inner diameter approximately identical to the inner diameter of the through hole <b>232</b> of the closure plate <b>23</b>. In addition, the core case <b>25</b> includes a bottom wall portion <b>252</b> configured to cover a rear aperture of the side wall portion <b>251</b>. Further, the core case <b>25</b> includes a flange portion <b>253</b> shaped into a circular shape and formed at a front end side of the side wall portion <b>251</b>. The core case <b>25</b> is attached to the closure plate <b>23</b> by bonding in an airtight manner a front surface of the flange portion <b>253</b> to a rear surface of the closure plate <b>23</b>. It is noted that a center of the side wall portion <b>251</b> of the core case <b>25</b> is aligned with a center of the through hole <b>232</b> of the closure plate <b>23</b>.

0052The shaft <b>53</b> is shaped into a round bar shape. The shaft <b>53</b> is inserted into the through hole <b>42</b> of the movable contact <b>40</b>, the through hole <b>63</b> of the arc protection member <b>60</b>, and an inside of the fixed core <b>52</b>. That is, the shaft <b>53</b> is disposed so as to penetrate through the movable contact 4<b>0</b>, the arc protection member <b>60</b>, and the fixed core <b>52</b>. The shaft <b>53</b> has its front end (first end) placed inside the sealed receptacle <b>20</b> and its rear end (second end) placed outside the sealed receptacle <b>20</b>.

0053The shaft <b>53</b> is provided at its front end with a latch <b>531</b> being in the form of a circular disk shape. The latch <b>531</b> has its outer diameter greater than the inner diameter of the through hole <b>42</b> of the movable contact <b>40</b>. Therefore, the latch <b>531</b> comes into contact with the front surface (fixed contact <b>31</b> side surface of the movable contact <b>40</b>) of the movable contact <b>40</b>. Therefore, the movable contact <b>40</b> moves rearward together with the shaft <b>53</b> when the shaft <b>53</b> moves rearward. The latch <b>531</b> locks the movable contact <b>40</b> in order to prevent the movable contact <b>40</b> from moving toward the fixed contact <b>31</b> by a spring force of the spring <b>51</b>.

0054The movable core <b>54</b> is made of a magnetic material and is shaped into a circular cylindrical shape. The movable core <b>54</b> has a hole <b>541</b> which penetrates through the movable core <b>54</b> along an axial direction of the movable core <b>54</b>. The rear end of the shaft <b>53</b> is inserted into the hole <b>541</b>. Thereby, the movable core <b>54</b> is coupled to the rear end of the shaft <b>53</b>. The movable core <b>54</b> is housed between a rear end surface of the fixed core <b>52</b> and the bottom wall portion <b>252</b> of the core case <b>25</b>. A distance between the rear end surface of the fixed core <b>52</b> and the bottom wall portion of the core case <b>25</b> is selected in consideration of a distance (contact gap) between the fixed contact <b>31</b> and the contact portion <b>41</b>.

0055A buffer member <b>571</b> is interposed between the movable core <b>54</b> and the fixed core <b>52</b>. The buffer member <b>571</b> is configured to absorb impact caused when the movable core <b>54</b> comes into contact with the fixed core <b>52</b>. Likewise, a buffer member <b>572</b> is interposed between the movable core <b>54</b> and the core case <b>25</b>. The buffer member <b>572</b> is configured to absorb impact caused when the movable core <b>54</b> comes into contact with the bottom wall portion <b>252</b>. The buffer members <b>571</b> and <b>572</b> are made of an elastic material (e.g. an elastomer such as a rubber) and are shaped into a circular annular shape.

0056The return spring (hereinafter abbreviated as "spring") <b>55</b> is a coil spring. The spring <b>55</b> is interposed between the cap <b>24</b> and the movable core <b>54</b>. The spring <b>55</b> is greater in a spring constant than the spring <b>51</b>. Therefore, the spring <b>55</b> keeps the movable core <b>54</b> away from the fixed core <b>52</b>. In other words, the spring <b>55</b> presses the movable core <b>54</b> against the bottom wall portion <b>252</b>. In this situation, the shaft <b>53</b> keeps the movable contact <b>40</b> away from the fixed contacts <b>31</b>. That is, the movable contact <b>40</b> is placed in the off-position.

0057The electric magnet device <b>56</b> includes a coil <b>561</b>, a coil bobbin <b>562</b>, and a yoke <b>563</b>. The coil bobbin <b>562</b> is configured to carry the coil <b>561</b>. The coil bobbin <b>562</b> is shaped into a circular cylindrical shape. The coil bobbin <b>562</b> has its inner diameter greater than an outer diameter of the side wall portion <b>251</b> of the core case <b>25</b>. The yoke <b>563</b> is made of a magnetic material, and is shaped into an approximately U-shape in order to cover a rear side, a right side, and a left side of the coil bobbin <b>562</b>. The electric magnet device <b>56</b> is attached to the rear surface side of the closure plate <b>23</b> while the core case <b>25</b> is inserted into the coil bobbin <b>562</b>. In the contact device <b>10</b>, the fixed core <b>52</b>, the movable core <b>54</b>, the yoke <b>563</b>, and the closure plate <b>23</b> constitute a magnetic circuit. In addition, as shown in <figref idref="f0008">FIG. 11</figref>, the coil <b>561</b> has its opposite ends respectively electrically connected to coil terminals <b>564</b>.

0058When the coil <b>561</b> is energized, a magnetic attraction is generated between the fixed core <b>52</b> and the movable core <b>54</b>. Thereby, the movable core <b>54</b> is moved toward the fixed core <b>52</b> against the spring force of the spring <b>55</b>. That is, the electromagnet device <b>56</b> is configured to generate the magnetic attraction between the fixed core <b>52</b> and the movable core <b>54</b>, thereby moving the movable core <b>54</b> toward the fixed core <b>52</b>. When the movable core <b>54</b> moves towards the fixed core <b>52</b>, the shaft <b>53</b> also moves forward. As a result, the latch <b>531</b> moves forward past the fixed contacts <b>31</b>. In this situation, the spring force of the spring <b>51</b> allows the movable contact <b>40</b> to come into contact with the fixed contacts <b>31</b> at the predetermined contact pressure.

0059In the contact device <b>10</b>, the spring <b>55</b> keeps the movable contact <b>40</b> in the off-position while the coil <b>561</b> is not energized. Meanwhile, the electric magnet device <b>56</b> keeps the movable contact <b>40</b> in the on-position while the coil <b>561</b> is energized. The spring <b>51</b> is interposed between the movable contact <b>40</b> and the bottom <b>62</b> so as to come into resilient contact with both the movable contact <b>40</b> and the bottom <b>62</b> irrespective of a position of the movable contact <b>40</b>.

0060Therefore, in the contact device <b>10</b> of the present embodiment, the spring <b>51</b> holds the arc protection member <b>60</b>. In other words, the spring <b>51</b> which makes the movable contact <b>40</b> come into contact with the fixed contact is used as a holding member for the arc protection member <b>60</b>. Thus, according to the contact device <b>10</b>, the pressing springs <b>1150</b> shown in <figref idref="f0020">FIG. <b>25</b></figref> are unnecessary. As a result, it is possible to reduce the number of parts necessitated for holding the arc protection member <b>60</b> and to reduce the production cost.

0061In addition, the nipper portion <b>241</b> of the cap <b>24</b> is fitted into the recess <b>63</b> of the arc protection member <b>60</b>. Therefore, the arc protection member <b>60</b> is positioned relative to the closure plate <b>23</b>. Thus, according to the contact device <b>10</b>, the arc protection member <b>60</b> can be easily assembled into the contact device <b>10</b>.

0062Further, as described in the above, the contact device <b>10</b> includes the dust prevention member <b>26</b>. Therefore, according to the contact device <b>10</b>, it is possible to prevent dust from intruding into the core case <b>57</b> through the through hole <b>63</b>. Thus, the dust does not prevent the movable core <b>54</b> from moving forward/rearward. For example, the aforementioned dust is dissipation particles generated by contact of the movable contact <b>40</b> with the fixed contact <b>31</b> or by separation of the movable contact <b>40</b> from the fixed contact <b>31</b>. Moreover, according to the contact device <b>10</b>, the dust prevention member <b>26</b> is fixed to the arc protection member <b>60</b> by use of the spring <b>51</b>. Therefore, it is unnecessary to add special parts for holding the dust prevention member.

0063Additionally, the arc protection member <b>60</b> is provided on its bottom <b>62</b> with the positioning portion <b>65</b>. Therefore, according to the contact device <b>10</b>, the spring <b>51</b> can be easily attached to the arc protection member <b>60</b>. Especially, the positioning portion <b>65</b> has its inner surface inclined such that the distance between the inner surface of the positioning portion <b>65</b> and the spring <b>51</b> increases as the distance from the bottom <b>62</b> increases. Therefore, the inner surface of the positioning portion <b>65</b> guides the rear end of the spring <b>51</b> to the inside of the positioning portion <b>65</b>. Thus, the spring <b>51</b> can be more easily attached to the arc protection member <b>60</b>. However, the positioning portion <b>65</b> does not need to have its inner surface inclined in an aforementioned manner. For example, as shown in <figref idref="f0005">FIGS. 8A and 8B</figref>, the inner surface of the positioning portion <b>65</b> may not be inclined.

0064As described in the above, the contact device <b>10</b> of the present embodiment includes the extinguishing unit <b>12</b>. As shown in <figref idref="f0006">FIGS. 9A and 9B</figref>, the extinguishing unit <b>12</b> includes a pair of permanent magnets <b>121</b> and a yoke <b>122</b>. The yoke <b>122</b> is configured to carry the pair of the permanent magnets <b>121</b>. The yoke <b>122</b> is made of a magnetic metal material (e.g. an iron) and is shaped into a U-shape. The yoke <b>122</b> includes a pair of side pieces <b>123</b> which extend across the upper and lower sides of the case <b>21</b> to hold the same therebetween. The yoke <b>122</b> further includes a connection piece configured to integrally connect first ends (right ends) of the side pieces <b>123</b> in the pair. As described in the above, the side pieces <b>123</b> in the pair are connected to each other at their first ends. Therefore, the sealed receptacle <b>20</b> can be mounted inside of the yoke <b>122</b> by a manipulation of sliding the yoke <b>122</b> from right to left of the sealed receptacle <b>20</b>. The permanent magnets <b>121</b> are fixed to surfaces of the side pieces <b>123</b> opposed to the sealed receptacle <b>20</b>, respectively. Therefore, the permanent magnets <b>121</b> in the pair are arranged on opposite sides of the sealed receptacle <b>20</b> with respect to a direction (upward/downward direction) crossing with (perpendicular to, in the illustrated instance) a direction (lateral direction in <figref idref="f0002">FIG. 2A</figref>) along which the movable contact <b>40</b> moves toward and away from the fixed contact <b>31</b>. The extinguishing unit <b>12</b> generates a magnetic field along the upward/downward direction. Therefore, the extinguishing unit <b>12</b> can extends an arc developed between the fixed contact <b>31</b> and the contact portion <b>41</b>, thereby extinguishing the same at a short time.

0065As shown in <figref idref="f0002">FIG. 2A and 2B</figref>, the housing <b>13</b> includes a base <b>70</b> and a cover <b>80</b>.

0066The cover <b>80</b> is shaped into a box shape having its rear surface opened. The cover <b>80</b> is attached to the base <b>70</b> to house the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12</b> between the cover <b>80</b> and the base <b>70</b>. As shown in <figref idref="f0002">FIG. 2B</figref>, the cover <b>80</b> is provided on its inner surface with a pair of holding pieces <b>81</b> configured to hold the connection piece <b>124</b> of the extinguishing unit <b>12</b> therebetween.

0067The contacts mechanism unit <b>11</b> is mounted on the base <b>70</b>. As shown in <figref idref="f0007">FIGS. 10A and 10B</figref>, the base <b>70</b> is shaped into a rectangular plate shape having enough dimensions to cover a rear surface side opening of the cover <b>80</b>. The base <b>70</b> includes two insertion holes <b>71</b> for the external connection terminals <b>34</b>. The respective insertion holes <b>71</b> penetrate through a front end portion of the base <b>70</b>. The base <b>70</b> includes two insertion holes <b>72</b> for the coil terminals <b>564</b>. The respective insertion holes <b>72</b> penetrate through a rear end portion of the base <b>70</b>.

0068In addition, two click pieces <b>125</b> and <b>126</b> are formed on the lower side piece <b>123</b> of the yoke <b>122</b> (side piece <b>123</b> adjacent to the base <b>70</b>). The respective click pieces <b>125</b> and <b>126</b> extend downward from the side piece <b>123</b>. The respective click pieces <b>125</b> and <b>126</b> are shaped into a rectangular plate shape. Moreover, the click pieces <b>125</b> and <b>126</b> are arranged along a longitudinal direction (lateral direction) of the side piece <b>123</b> and are spaced from each other at a predetermined distance.

0069The base <b>70</b> is provided on its upper surface with a pair of wall portions <b>73</b> which are parallel to each other. The wall portion <b>73</b> has its longitudinal direction parallel to the lateral direction. A clearance between the wall portions <b>73</b> defines a groove <b>74</b>. The groove <b>74</b> is defined as an attachment recess into which the respective click pieces <b>125</b> and <b>126</b> are inserted. When the click pieces <b>125</b> and <b>126</b> of the extinguishing unit <b>12</b> are inserted into the groove <b>74</b>, the wall portions <b>73</b> hold the respective click pieces <b>125</b> and <b>126</b> therebetween in the forward/rearward direction. The groove <b>74</b> and the click pieces <b>125</b> and <b>126</b> constitute an attachment unit configured to attach the extinguishing unit <b>12</b> to the base <b>70</b>. It is noted that the attachment unit may be constituted by an attachment protrusion provided to any one of the yoke <b>122</b> and the base <b>70</b> and an attachment recess provided to the other.

0070Herein, the groove <b>74</b> has its right end opened. Therefore, when the extinguishing unit <b>12</b> is attached to the base <b>70</b>, the click pieces <b>125</b> and <b>126</b> can be inserted into the groove <b>74</b> from a lateral side (right side) instead of an upper side. In brief, the extinguishing unit <b>12</b> can be attached to the base <b>70</b> by sliding the extinguishing unit <b>12</b> from right to left of the base <b>70</b>. Further, as described in the above, the sealed receptacle <b>20</b> can be mounted inside the yoke <b>122</b> by sliding the yoke <b>122</b> from right to left of the sealed receptacle <b>20</b>. Accordingly, the extinguishing unit <b>12</b> can be attached to the base after the contacts mechanism unit <b>11</b> is mounted on the base <b>70</b>, as shown in <figref idref="f0008">FIG. 11</figref>.

0071Additionally, a latching protrusion <b>75</b> for preventing detachment of the extinguishing unit <b>12</b> is formed on a bottom of the groove <b>74</b>. The latching protrusion <b>75</b> is configured such that a left side surface of the latching protrusion <b>75</b> comes into contact with a right side surface of the click piece <b>126</b> when the extinguishing unit <b>12</b> is placed in a predetermined position relative to the base <b>70</b>. In other words, the latching protrusion <b>75</b> locks the click piece <b>126</b> such that the extinguishing unit <b>12</b> is kept placed in the predetermined position. Therefore, the extinguishing unit <b>12</b> is not allowed to move towards a direction (direction where the extinguishing unit <b>12</b> is detached from the base <b>70</b>) opposed to a direction where the extinguishing unit <b>12</b> is attached to the base <b>70</b> after being placed in the predetermined position.

0072In the following, an explanation is made to a process of housing the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12</b> in the housing <b>13</b>. First, as shown in <figref idref="f0008">FIG. 11</figref>, the contacts mechanism unit <b>11</b> is mounted on the base <b>70</b>. In this situation, the external connection terminals <b>34</b> and the coil terminals <b>564</b> are pressed into the insertion holes <b>71</b> and <b>72</b> of the base <b>70</b>, respectively. Next, as shown in <figref idref="f0008">FIG. 12</figref>, the click pieces <b>125</b> and <b>126</b> are inserted into the groove <b>74</b> from one end side (right end side) of the base <b>70</b> by sliding the extinguishing unit <b>12</b> along a width direction of the base <b>70</b>. Thereby, the extinguishing unit <b>12</b> is attached to the base <b>70</b>. In this process, the click piece <b>126</b> rides over the latching protrusion <b>75</b> to be locked by the latching protrusion <b>75</b>. Subsequently, after the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12</b> are attached to the base <b>70</b> as shown in <figref idref="f0009">FIGS. 13A and 13B</figref>, the cover <b>80</b> is attached to the base <b>70</b> so as to cover the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12</b>.

0073By the way, the prior contact device is assembled by attaching the contacts mechanism unit to the base and subsequently attaching the cover to the base. In this situation, the extinguishing unit is not still attached to the base. Therefore, it is difficult to insert the connection piece of the yoke of the extinguishing unit between the holding pieces in the pair when attaching the cover to the base. Thus, the extinguishing unit can not be easily assembled into the housing.

0074By contrast, in the contact device <b>10</b> of the present embodiment, the extinguishing unit <b>12</b> can be attached to the base <b>70</b> by inserting the click pieces <b>125</b> and <b>126</b> into the groove <b>74</b> of the base <b>70</b>. Therefore, the extinguishing unit <b>12</b> is positioned relative to the base <b>70</b> before the cover <b>80</b> is attached to the base <b>70</b>. Thus, it is possible to easily inert the connection piece <b>124</b> of the extinguishing unit <b>12</b> between the holding pieces <b>81</b> of the pair of the cover <b>80</b>. Consequently, the extinguishing unit <b>12</b> can be easily assembled into the housing <b>13</b>. In the aforementioned instance, the yoke <b>122</b> is provided with the click pieces <b>125</b> and <b>126</b> as the attachment protrusions. Such the attachment protrusions may be provided to the base <b>70</b>. With this arrangement, the groove <b>74</b> as the attachment recess is provided to the base <b>70</b>, rather than the yoke <b>122</b>. In other words, any one of the yoke <b>122</b> and the base <b>70</b> may include the attachment protrusion and the other may include the attachment recess configured to receive the attachment protrusion.

0075By the way, the latching protrusion <b>75</b> is provided at its front end with an inclined surface <b>76</b>. The inclined surface <b>76</b> is inclined so as to lower its right end relative to its left end. In addition, the click piece <b>126</b> is provided at its front end with an inclined surface <b>127</b>. The inclined surface <b>127</b> is inclined so as to raise its left end relative to its right end. The inclined surface <b>76</b> of the latching protrusion <b>75</b> and the inclined surface <b>127</b> of the click piece <b>126</b> are arranged to come into contact with each other when the extinguishing unit <b>12</b> is attached to the base <b>70</b> (the inclined surface <b>76</b> of the latching protrusion <b>75</b> and the inclined surface <b>127</b> of the click piece <b>126</b> are opposed to each other in a slide direction of the extinguishing unit <b>12</b>). Therefore, the click piece <b>126</b> can easily ride over the latching protrusion <b>75</b> when the extinguishing unit <b>12</b> is slid to be attached to the base <b>70</b>. Thus, the extinguishing unit <b>12</b> can be easily attached to the base <b>70</b>.

0076As mentioned in the above, the latching protrusion <b>75</b> is provided with the inclined surface <b>76</b> at a portion which is opposed to the click piece <b>126</b> in the slide direction of the extinguishing unit <b>12</b>. The inclined surface <b>76</b> guides the click piece <b>126</b> such that the click piece <b>126</b> rides over the latching protrusion <b>75</b>. Therefore, the click piece <b>126</b> can easily ride over the latching protrusion <b>75</b> when the extinguishing unit <b>12</b> is attached to the base <b>70</b>. Thus, the extinguishing unit <b>12</b> can be easily housed in the housing <b>13</b>.

0077Moreover, the click piece <b>126</b> is provided with the inclined surface <b>127</b> at a portion which is opposed to the latching protrusion <b>75</b> in the slide direction of the extinguishing unit <b>12</b>. The inclined surface <b>127</b> guides the latching protrusion <b>75</b> such that the click piece <b>126</b> rides over the latching protrusion <b>75</b>. Therefore, the click piece <b>126</b> can easily ride over the latching protrusion <b>75</b> when the extinguishing unit <b>12</b> is attached to the base <b>70</b>.

0078If the inclined surface <b>127</b> is provided to the click piece <b>126</b>, it is unnecessary to provide the inclined surface <b>76</b> to the latching protrusion 7<b>5</b>. Likewise, if the inclined surface <b>76</b> is provided to the latching protrusion <b>75</b>, it is unnecessary to provide the inclined surface <b>127</b> to the click piece <b>126</b>.

0079In addition, guide surfaces <b>77</b> are formed at right ends of both inner surfaces of the groove <b>74</b>, respectively. The guide surface <b>77</b> is configured to guide the click piece <b>126</b> into the groove <b>74</b>. The guide surface <b>77</b> is an inclined surface which is inclined such that a width of the groove <b>74</b> is made greater towards one end (right end) of the groove <b>74</b> than at the other end. The guide surface <b>77</b> allows the click piece <b>126</b> to be easily inserted into the groove <b>74</b>. Therefore, according to the contact device 10, the extinguishing unit <b>12</b> can be easily housed in the housing <b>13</b>.

0080Respective <figref idref="f0010">FIGS 14A and 14B</figref> show a modification of the contact device <b>10</b> of the present embodiment. In <figref idref="f0010">FIGS. 14A and 14B</figref>, the positioning portion <b>65</b> is shaped into a cylindrical shape (circular cylindrical shape, in the illustrated instance) having enough dimensions to be inserted into the inside of the spring <b>51</b>. Also in this modification, the spring <b>51</b> can be easily attached to the arc protection member <b>60</b>. In addition, as shown in <figref idref="f0010">FIGS. 14C and 14D</figref>, the positioning portion <b>65</b> is preferred to have its outer surface inclined such that a distance between the outer surface and the spring <b>51</b> increases as a distance from the bottom <b>62</b> of the arc protection member <b>60</b> increases. In other words, the positioning portion <b>65</b> is preferred to be shaped to have a tapered shape. In this situation, the outer surface of the positioning portion <b>65</b> guides the spring <b>51</b> to the inside of the positioning portion <b>65</b>. Therefore, the spring <b>51</b> can be more easily attached to the arc protection member <b>60</b>. The positioning portion <b>65</b> is not always required to have a cylindrical shape. The positioning portion <b>65</b> may be defined by a plurality of protrusions configured to be inserted into the inside of the spring <b>51</b>.

0081Besides, in the contact device <b>10</b>, the nipper portion <b>241</b> of the cap <b>24</b> is shaped into a rectangular shape. Therefore, according to the contact device <b>10</b>, it is possible to position the arc protection member <b>60</b> without rotating. Meanwhile, in the prior contact device <b>1000</b>, the peripheral wall <b>1141</b> of the arc protection member <b>1140</b> is only pressed against an inner surface of the contact case <b>1110</b>. Therefore, according to the prior contact device <b>1000</b>, it is necessary to house the arc protection member <b>1140</b> in the sealed receptacle <b>1100</b> while adjusting a deviation caused by rotation of the arc protection member <b>1140</b>. According to the contact device <b>10</b> of the present embodiment, it is unnecessary to house the arc protection member <b>60</b> in the sealed receptacle <b>20</b> while adjusting a deviation caused by rotation of the arc protection member <b>60</b>. Thus, the contact device <b>10</b> can be easily assembled. As a result, it is possible to reduce the production cost of the contact device <b>10</b>.

0082Respective <figref idref="f0011">FIGS. 15A to 15C</figref> show a modification of the contact device <b>10</b> of the present embodiment. In <figref idref="f0011">FIGS. 15A to 15C</figref>, the cap <b>24A</b> is shaped into a circular disk shape.

0083In the modification shown in <figref idref="f0011">FIG. 15A</figref>, a protrusion <b>233</b> for positioning is formed on the front surface of the closure plate <b>23</b>. The protrusion <b>233</b> is shaped to be fitted into the recess <b>64</b>. The protrusion <b>233</b> is formed through a process of striking a center portion of the closure plate <b>23</b> to protrude it forwardly, for example. In the modification shown in <figref idref="f0011">FIG. 15A</figref>, the cap <b>24A</b> is provided to a front surface of the protrusion <b>233</b>. Also in this situation, the arc protection member <b>60</b> can be unrotatably positioned relative to the closure plate <b>23</b> by engagement of the protrusion <b>233</b> into the recess <b>64</b>.

0084In the modification shown in <figref idref="f0011">FIG. 15B</figref>, two circular protrusions <b>244</b> and <b>245</b> for positioning extends from the front surface of the cap <b>24A</b>. Meanwhile, two recesses <b>641</b> and <b>642</b> for positioning are formed in the rear surface of the bottom <b>62</b> of the arc protection member <b>60</b>. The recesses <b>641</b> and <b>642</b> are corresponding to the protrusions <b>244</b> and <b>245</b>, respectively. Therefore, in the modification shown in <figref idref="f0011">FIG. 15B</figref>, the arc protection member <b>60</b> is positioned relative to the closure plate <b>23</b> by engagement of the protrusion <b>244</b> and the recess <b>641</b> together with engagement of the protrusion <b>245</b> and the recess <b>642</b>. Although each of the protrusions <b>244</b> and <b>245</b> has a circular shape, a plurality of the protrusions <b>244</b> and <b>245</b> can prevent rotation of the arc protection member <b>60</b>. Besides, a plurality of the protrusions for positioning may be formed on the cap <b>24</b> instead of the closure plate <b>23</b>.

0085In the modification shown in <figref idref="f0011">FIG. 15C</figref>, the closure plate <b>23</b> is provided on its front surface with a protrusion (first protrusion for positioning) <b>234</b> for positioning. The bottom <b>62</b> of the arc protection member <b>60</b> is provided in its rear surface with a recess (first recess for positioning recess) <b>643</b> for positioning configured to receive the protrusion <b>234</b>. Additionally, in the modification shown in <figref idref="f0011">FIG. 15C</figref>, the cap <b>24A</b> is defined as the second protrusion for positioning. The bottom <b>62</b> is provided in its rear surface with a recess (second recess for positioning) <b>644</b> for positioning configured to receive the cap <b>24A</b>. Therefore, in the modification shown in <figref idref="f0011">FIG. 15C</figref>, the arc protection member <b>60</b> is positioned relative to the closure plate <b>23</b> by engagement of the protrusion <b>234</b> and the recess <b>643</b> together with engagement of the cap <b>24A</b> and the recess <b>644</b>. Although each of the cap <b>24A</b> and the protrusion <b>234</b> has a circular shape, a plurality of the cap <b>24A</b> and the protrusion <b>234</b> can prevent rotation of the arc protection member <b>60</b>.

0086Moreover, in contrast to the aforementioned instance, the arc protection member <b>60</b> may include a protrusion for positioning, and the closure plate <b>23</b> or the cap <b>24</b> may include a recess for positioning into which the protrusion for positioning of the arc protection member <b>60</b> is fitted. The closure plate <b>23</b> may include plural protrusions for positioning or plural recesses for positioning.

0087Respective <figref idref="f0012 f0013 f0014 f0015">FIGS. 16 to 19</figref> show a modification of the shock absorber <b>58</b>. In the shock absorber <b>58</b> shown in <figref idref="f0012">FIGS. 16A and 16B</figref>, the second resilient portion <b>582</b> includes a cutout <b>586</b> communicating with the through hole <b>584</b>. The cutout <b>586</b> is of a semielliptical shape having its width decreasing as an increase of a distance from the center of the second resilient portion <b>582</b>. According to the shock absorber <b>58</b> shown in <figref idref="f0012">FIGS. 16A and 16B</figref>, the through hole <b>584</b> can easily expand due to resilient deformability given to the second resilient portion <b>582</b>. Therefore, the shock absorber <b>58</b> can be more easily attached to the fixed core <b>52</b>. In addition, a used amount of a material for the shock absorber <b>58</b> can be reduced by an amount of material corresponding to the cutout <b>586</b>. Thus, the production cost can be reduced. Besides, a shape of the cutout <b>586</b> is not limited to the aforementioned instance. For example, as the shock absorber <b>58</b> shown in <figref idref="f0012">FIGS. 16C and 16D</figref>, the cutout <b>586</b> may extend to the outer edge of the second resilient portion <b>582</b>. Alternately, as the shock absorber <b>58</b> shown in <figref idref="f0012">FIGS. 16E and 16F</figref>, the first resilient portion <b>581</b> also may be provided with a cutout <b>587</b> in a similar manner as the second resilient portion <b>582</b>. With this arrangement, the cutout <b>587</b> of the first resilient portion <b>581</b> communicates with the cutout <b>586</b> of the second resilient portion <b>582</b>.

0088In brief, it is sufficient that at least one of the first resilient portion <b>581</b> and the second resilient portion <b>582</b> is provided with a cutout communicating with the through holes <b>583</b> and <b>584</b> thereof.

0089In the shock absorber <b>58</b> shown in <figref idref="f0013">FIG. 17</figref>, the first resilient portion <b>581</b> is provided on its front surface with four protruded portions <b>588A</b>. The protruded portions <b>588A</b> are each shaped into a circular shape, and are arranged at regular intervals along a circumferential direction of the first resilient portion <b>581</b>. In addition, the second resilient portion <b>582</b> is provided on its rear surface with four protruded portions <b>588B</b>. The protruded portions <b>588B</b> are each shaped into a circular shape, and are arranged at regular intervals along a circumferential direction of the first resilient portion <b>582</b>. Besides, the number of the protruded portions <b>588A</b> and the number of the protruded portions <b>588B</b> are not limited to four. For example, the number of the protruded portions <b>588A</b> and the number of the protruded portions <b>588B</b> may be one to three, or more than four.

0090According to the shock absorber <b>58</b> shown in <figref idref="f0013">FIG. 17</figref>, the protruded portions <b>588A</b> decrease a contact area of the first resilient portion <b>581</b> and the cap <b>24</b> relative to that of the shock absorber <b>58</b> shown in <figref idref="f0012">FIG. 16</figref>, and the protruded portions <b>588B</b> decrease a contact area of the second resilient portion <b>582</b> and the closure plate <b>23</b> relative to that of the shock absorber <b>58</b> shown in <figref idref="f0012">FIG. 16</figref>. Therefore, a vibration caused by contact of the movable core <b>54</b> with the fixed core <b>52</b> is restrained from being transmitted to the cap <b>24</b> and the closure plate <b>23</b>. Consequently, according to the contact device <b>10</b> having the shock absorber <b>58</b> shown in <figref idref="f0013">FIG. 17</figref>, it is possible to more reduce an operation noise of the contact device <b>10</b> by reducing the vibration transmitted outside.

0091In the shock absorber <b>58</b> shown in <figref idref="f0014">FIG. 18</figref>, the first resilient portion <b>581</b> is provided in its front surface with four recessed portions <b>589A</b>. The recessed portions <b>589A</b> are arranged at regular intervals along a circumferential direction of the first resilient portion <b>581</b>. In addition, the second resilient portion <b>582</b> is provided in its rear surface with four recessed portions <b>589B</b>. The recessed portions <b>589B</b> are arranged at regular intervals along a circumferential direction of the second resilient portion <b>582</b>. Besides, the number of the recessed portions <b>589A</b> and the number of the recessed portions <b>589B</b> are not limited to four. For example, the number of the recessed portions <b>589A</b> and the number of the recessed portions <b>589B</b> may be one to three, or more than four.

0092Also according to the shock absorber <b>58</b> shown in <figref idref="f0014">FIG. 18</figref>, the recessed portions <b>589A</b> decrease the contact area of the first resilient portion <b>581</b> and the cap <b>24</b> relative to that of the shock absorber <b>58</b> shown in <figref idref="f0012">FIG. 16</figref>, and the recessed portions <b>589B</b> decrease the contact area of the second resilient portion <b>582</b> and the closure plate <b>23</b> relative to that of the shock absorber <b>58</b> shown in <figref idref="f0012">FIG. 16</figref>. Therefore, according to the contact device <b>10</b> having the shock absorber <b>58</b> shown in <figref idref="f0014">FIG. 18</figref>, it is possible to more reduce the operation noise of the contact device <b>10</b>.

0093In brief, it is sufficient that the protruded portions <b>588A</b> or the recessed portions <b>589A</b> are provided to a surface of the first resilient portion <b>581</b> opposed to the cap <b>24</b> and that the protruded portions <b>588B</b> or the recessed portions <b>589B</b> are provided to a surface of the second resilient portion <b>582</b> opposed to the closure plate <b>23</b>.

0094In the shock absorber <b>58</b> shown in <figref idref="f0015">FIG. 19</figref>, the first resilient portion <b>581</b> is provided on its front surface (surface opposed to the cap <b>24</b>) with a protruded portion <b>588C</b>, and the second resilient portion <b>582</b> is provided on its rear surface (surface opposed to the closure plate <b>23</b>) with a protruded portion <b>588D</b>. The protruded portion <b>588C</b>, being of an annular shape, extends around an inner periphery of the first resilient portion <b>581</b>. This protruded portion <b>588C</b> is defined as a periphery wall surrounding the through hole <b>583</b>. The protruded portion <b>588D</b>, being of an annular shape, extends around an inner periphery of the second resilient portion <b>582</b>. This protruded portion <b>588D</b> is defined as a periphery wall surrounding the through hole <b>584</b>.

0095In brief, it is sufficient that the first resilient portion <b>581</b> includes a periphery wall surrounding the through hole <b>583</b> and that the second resilient portion <b>582</b> includes a periphery wall surrounding the through hole <b>584</b>.

0096In the shock absorber <b>58</b> shown in <figref idref="f0015">FIG. 19</figref>, the protruded portion <b>588C</b> comes into contact with the cap <b>24</b> and the protruded portion <b>588D</b> comes into contact with the closure plate <b>23</b>.

0097Therefore, it is possible to prevent a dust <b>2000</b> from coming into the inside of the core case <b>25</b> (especially, a clearance between the fixed core <b>52</b> and the movable core <b>54</b>) via the through holes <b>583</b> and <b>584</b>. Thus, it is possible to improve reliability of an on-off operation of the contact device <b>10</b>. For example, the dust <b>2000</b> is dissipation particles generated by contact of the contact portion <b>41</b> with the fixed contact <b>31</b> or by separation of the contact portion <b>41</b> from the fixed contact <b>31</b>.

0098By the way, in the contact device <b>10</b> of the present embodiment, the screw hole <b>33</b> is provided to the fixed terminal <b>30</b> in order to fix the external connection terminal <b>34</b> to the fixed terminal <b>30</b>. Therefore, a process of forming the screw hole <b>33</b> in the fixed terminal <b>30</b> is necessary. Generally, since the process of forming the screw hole <b>33</b> costs time, the production cost increases. Additionally, the fixed terminal <b>30</b> needs to be designed to have its diameter greater than a diameter of screw hole <b>33</b> (diameter of the fixed screw). Therefore, the fixed terminal <b>30</b> sees reduced design flexibility

0099Consequently, in a modification of the contact device <b>10</b> shown in <figref idref="f0016">FIG. 20</figref>, the fixed terminal <b>30</b> has its front end with a deformation portion <b>35</b> instead of the screw hole <b>33</b>. Meanwhile, the external connection terminal <b>34</b> is provided with an insertion hole <b>341</b> having a circular shape. Prior to attaching the external connection terminal <b>34</b> to the fixed terminal <b>30</b>, the deformation portion <b>35</b> keeps its original columnar shape with its outer diameter being smaller than an inner diameter of the insertion hole <b>341</b>.

0100When the external connection terminal <b>34</b> is attached to the fixed terminal <b>30</b>, first, the deformation portion <b>35</b> is inserted into the insertion hole <b>341</b> of the external connection terminal <b>34</b> as shown in <figref idref="f0016">FIG. 21A</figref>. Next, as shown in <figref idref="f0016">FIG. 21B</figref>, the deformation portion <b>35</b> is plastically deformed to come into close contact with an inner periphery of the insertion hole <b>341</b>. In other words, the deformation portion <b>35</b> and the insertion hole <b>341</b> are used for riveting (e.g. spin riveting and radial riveting). In a situation shown in <figref idref="f0016">FIG. 21B</figref>, a most part of the deformation portion <b>35</b> is plastically deformed. However, a part of the deformation portion <b>35</b> which comes into contact with inner periphery of the insertion hole <b>341</b> is elastically deformed, rather than is plastically deformed. Therefore, the deformation portion <b>35</b> comes into strongly close contact with the inner periphery of the insertion hole <b>341</b>. Thus, the external connection terminal <b>34</b> is fixed successfully to the fixed terminal <b>30</b>. Additionally, conduction between the external connection terminal <b>34</b> and the fixed terminal <b>30</b> is successfully made because contact resistance between the external connection terminal <b>34</b> and the fixed terminal <b>30</b> decreases.

0101As mentioned in the above, in the modification shown in <figref idref="f0016">FIG. 20</figref>, the fixed terminal <b>30</b> is provided with the deformation portion <b>35</b> at its front end. The deformation portion <b>35</b> is plastically deformed to fix the external connection terminal <b>34</b> to the fixed terminal <b>30</b>. That is, the fixed terminal <b>30</b> is secured to the external connection terminal <b>34</b> by plastically and elastically deforming a part of the fixed terminal <b>30</b>. Therefore, the external connection terminal <b>34</b> is not necessitated to be screwed to the fixed terminal <b>30</b>. According to the modification shown in <figref idref="f0016">FIG. 20</figref>, the process of forming the screw hole <b>33</b> in the fixed terminal <b>30</b> can be eliminated, and therefore the production cost can be reduced. Additionally, it is possible to improve the flexibility of the design of the fixed terminal <b>30</b> because the diameter of the fixed terminal <b>30</b> is independent from the diameter of the screw hole <b>33</b>.

0102Especially, the deformation portion <b>35</b> is a protrusion extending from the fixed terminal <b>30</b> toward the external connection terminal <b>34</b>. The insertion hole <b>341</b> defined as an insertion portion into which the deformation portion <b>35</b> is inserted is formed in the external connection terminal <b>34</b>. Therefore, the external connection terminal <b>34</b> can be riveted to the fixed terminal <b>30</b> with the deformation portion <b>35</b> being inserted into the insertion hole <b>341</b> followed by being plastically deformed. Consequently, the external connection terminal <b>34</b> can be easily fixed to the fixed terminal <b>30</b>.

0103In addition, a tapered surface <b>342</b> is formed in a periphery of the insertion hole <b>341</b>. The tapered surface <b>342</b> expands the insertion hole <b>341</b> to be greater towards its front side (side opposed to the fixed core <b>52</b>) than at its rear end. Therefore, when the deformation portion <b>35</b> is plastically deformed, the deformation portion <b>35</b> is deformed to come into close contact with the tapered surface <b>342</b>. A contact area between the external connection terminal <b>34</b> and the deformation portion <b>35</b> can be increased by forming the tapered surface <b>342</b>. Consequently, it is possible to prevent the external connection terminal <b>34</b> from rotating around the deformation portion <b>35</b>. Further, the contact resistance between the external connection terminal <b>34</b> and the fixed terminal <b>30</b> can be more decreased. It is noted that the tapered surface <b>342</b> does not need to be formed in the external connection terminal <b>34</b> (see <figref idref="f0017">FIGS. 22A to 22C</figref>). However, in view of the above merits, the tapered surface <b>342</b> is preferred to be formed.

0104In an instance shown in <figref idref="f0018">FIG. 23D</figref>, a junction between the fixed terminal <b>30</b> and the external connection terminal <b>34</b> has poor resistance to a stress applied along a circumference direction of the insertion hole <b>341</b>. This is caused by the inner peripheral shape of the insertion hole <b>341</b> of the external connection terminal <b>34</b> being a precise circular shape. In the instance shown in <figref idref="f0018">FIG. 23D</figref>, when stress is applied along the circumference direction of the insertion hole <b>341</b> to the external connection terminal <b>34</b>, the external connection terminal <b>34</b> is likely to rotate around the fixed terminal <b>30</b>.

0105In view of the above, as shown in <figref idref="f0018">FIG. 23A</figref>, the insertion hole <b>341</b> may have its inner peripheral shape being an elliptical shape. With this arrangement, the junction between the fixed terminal <b>30</b> and the external connection terminal <b>34</b> has excellent resistance to a moment developed about an central axis of the fixed terminal <b>30</b> (i.e., the stress applied along the circumference direction of the insertion hole <b>341</b>). Therefore, it is possible to prevent the external connection terminal <b>34</b> from rotating around the fixed terminal <b>30</b>.

0106Shapes of the insertion hole <b>341</b> and the deformation portion <b>35</b> are not limited in the aforementioned instance. For example, as shown in <figref idref="f0018">FIG. 23B</figref>, the insertion hole <b>341</b> may have its inner periphery of a rectangular shape (regular tetragon shape, in the illustrated instance). Alternately, as shown in <figref idref="f0018">FIG. 23C</figref>, plural (four, in the illustrated instance) cutouts <b>344</b> may be formed in the inner periphery of the insertion hole <b>341</b> having a precise circular inner periphery, and may be arranged at regular intervals along the circumference direction of the insertion hole <b>341</b>. In brief, when the inner peripheral shape of the insertion hole <b>341</b> is selected from any one of shapes but the precise circular shape, it is possible to prevent the external connection terminal <b>34</b> from rotating relative to the fixed terminal <b>30</b>.

0107By the way, as shown in <figref idref="f0017">FIG. 22D</figref>, instead of the insertion hole <b>341</b>, a cutout <b>343</b> may be formed in the external connection terminal <b>34</b>. The cutout <b>343</b> communicates with an outside of the external connection terminal <b>34</b> at one width end of the external connection terminal <b>34</b>. Also in this situation, the external connection terminal <b>34</b> can be fixed to the fixed terminal <b>30</b> by use of the deformation portion <b>35</b> and the cutout <b>343</b>. Especially, it is possible to improve workability of the riveting process, because the deformation portion <b>35</b> can easily pass through the cutout <b>343</b> rather than the insertion hole <b>341</b>.

0108In a modification shown in <figref idref="f0019">FIGS. 24A and 24B</figref>, the fixed terminal <b>30</b> is provided at its front end with two deformation portions <b>35</b>. Additionally, the external connection terminal <b>34</b> includes two insertion holes <b>341</b> respectively corresponding to the two deformation portions <b>35</b>.

0109With this arrangement, it is possible to prevent the external connection terminal <b>34</b> from rotating around the fixed terminal <b>30</b>. Besides, as shown in <figref idref="f0019">FIG. 24C</figref>, the cutout <b>343</b> may be formed instead of the two insertion holes <b>341</b>. Also with this arrangement, the external connection terminal <b>34</b> is fixed to the fixed terminal <b>30</b> by use of the two deformation portions <b>35</b> and the cutout <b>343</b>. Especially, it is possible to improve workability of the riveting process, because the deformation portion <b>35</b> can easily pass through the cutout <b>343</b> rather than the insertion hole <b>341</b>. Besides, the number of the deformation portions <b>35</b> and the number of the insertion holes <b>341</b> may be three or more.

0110In another respect, the aforementioned contact device <b>10</b> of the present embodiment is defined as follows. That is, the contact device <b>10</b> includes the sealed receptacle <b>20</b> configured to house the fixed contact <b>31</b> and the movable contact <b>40</b>, and the drive unit <b>50</b> configured to move the movable contact <b>40</b> between the on-position where the movable contact <b>40</b> is kept in contact with the fixed contact <b>31</b> and the off-position where the movable contact <b>40</b> is kept away from the fixed contact <b>31</b>. The sealed receptacle <b>20</b> includes the case <b>21</b> made of dielectric materials and the closure plate <b>23</b>. The case <b>21</b> is provided with the aperture <b>211</b> in its rear wall (first wall). The closure plate <b>23</b> is secured in an airtight manner to the periphery of the aperture <b>211</b> of the case <b>21</b>. The fixed contact <b>31</b> is fixed to the front wall (second wall) of the case <b>21</b> which is opposed to the rear wall of the case 2<b>1</b>. The movable contact <b>40</b> is interposed between the fixed contact <b>31</b> and the closure plate <b>23</b>. The drive unit <b>50</b> includes the shaft <b>53</b>, and the actuator including the fixed core <b>52</b> penetrating through the closure plate <b>23</b>, the movable core <b>54</b>, and the electromagnet device <b>56</b>. The shaft <b>53</b> is disposed to penetrate through the movable contact <b>40</b> and the fixed core <b>52</b>. The shaft <b>53</b> is provided at its front end (first end) inside the sealed receptacle <b>20</b> with the latch <b>531</b> coming into contact with the fixed contact <b>31</b> side surface of the movable contact <b>40</b>. The shaft <b>53</b> has its rear end (second end) outside the sealed receptacle <b>20</b> coupled (secured) to the movable core <b>54</b>. The electromagnet device <b>56</b> is configured to generate a magnetic attraction between the fixed core <b>52</b> and the movable core <b>54</b>. The aforementioned actuator is configured to control the electromagnet device <b>56</b> to move the shaft <b>53</b> along its axial direction between the position where the latch <b>531</b> separates the movable contact <b>40</b> from the fixed contact <b>31</b> and the position where the latch <b>531</b> allows the movable contact <b>40</b> to come into contact with the fixed contact <b>31</b>. The fixed core <b>52</b> is provided with the flange <b>521</b> configured to be hooked over the periphery of the through hole <b>232</b> of the closure plate <b>23</b> through which the fixed core <b>52</b> penetrates. The contact device <b>10</b> includes the cap <b>24</b> secured to the closure plate <b>23</b> such that the flange <b>521</b> of the fixed core <b>52</b> is held between the cap <b>24</b> and the closure plate <b>23</b>. The contact device <b>10</b> further includes the shock absorber <b>58</b>. The shock absorber <b>58</b> includes the first resilient portion <b>581</b>, the second resilient portion <b>582</b>, and the connection portion <b>585</b>. The first resilient portion <b>581</b> is interposed between the flange <b>521</b> of the fixed core <b>52</b> and the cap <b>24</b>. The second resilient portion <b>582</b> is interposed between the flange <b>521</b> of the fixed core <b>52</b> and the closure plate <b>23</b>. The connection portion <b>585</b> is configured to integrally connect the outer edge of the first resilient portion <b>581</b> to the outer edge of the second resilient portion <b>582</b>.

0111Therefore, according to the contact device <b>10</b>, it is unnecessary to attach individually the first resilient portion <b>581</b> and the second resilient portion <b>582</b> to the fixed core <b>52</b>. Thus, the shock absorber <b>58</b> can be easily attached to the fixed core <b>52</b>. Moreover, since the first resilient portion <b>581</b> and the second resilient portion <b>582</b> which each have poor manipulability are integrally connected to each other through the connection portion, it is easy to manipulate the shock absorber <b>58</b>.

0112In another respect, the aforementioned contact device <b>10</b> of the present embodiment is defined as follows. That is, the contact device <b>10</b> includes the contacts mechanism unit <b>11</b>, the extinguishing unit <b>12</b>, and the housing <b>13</b>. The contacts mechanism unit <b>11</b> includes the sealed receptacle <b>20</b> and the drive unit <b>50</b>. The sealed receptacle <b>20</b> is configured to house the fixed contact <b>31</b> and the movable contact <b>40</b>. The drive unit <b>50</b> is configured to move the movable contact <b>40</b> between the on-position where the movable contact <b>40</b> is kept in contact with the fixed contact <b>31</b> and the off-position where the movable contact <b>40</b> is kept away from the fixed contact <b>31</b>. The extinguishing unit <b>12</b> includes the pair of the permanent magnets <b>121</b> and the yoke <b>122</b> configured to hold the pair of the permanent magnets <b>121</b>. The permanent magnets <b>121</b> in the pair are arranged on opposite sides of the sealed receptacle <b>20</b> with respect to the direction crossing with the direction along which the movable contact <b>40</b> moves toward and away from the fixed contact <b>31</b>. The housing <b>13</b> includes the base <b>70</b> on which the contacts mechanism unit <b>11</b> is mounted, and the cover <b>80</b> configured to be attached to the base <b>70</b> such that the contacts mechanism unit <b>11</b> and the extinguishing unit <b>12</b> are housed between the base <b>70</b> and the cover <b>80</b>. The any one of the yoke <b>122</b> and the base <b>70</b> is provided with the attachment protrusion with the other being provided with the attachment recess configured to receive the attachment protrusion.

0113According to this configuration, the contact device <b>10</b> can be easily assembled.

0114In another respect, the contact device <b>10</b> shown in <figref idref="f0016">FIG. 20</figref> is defined as follows. That is, the contact device <b>10</b> includes a sealed unit and the drive unit <b>50</b>. The sealed unit includes the fixed contact <b>31</b>, the movable contact <b>40</b>, and the sealed receptacle <b>20</b> configured to house the fixed contact <b>31</b> and the movable contact <b>40</b>. The drive unit <b>50</b> is configured to move the movable contact <b>40</b> between the on-position where the movable contact <b>40</b> is kept in contact with the fixed contact <b>31</b> and the off-position where the movable contact <b>40</b> is kept away from the fixed contact <b>31</b>. The sealed unit includes the fixed terminal <b>30</b> penetrating through the wall (front wall) of the sealed receptacle <b>20</b>, and the external connection terminal <b>34</b> adapted to be connected to an external circuit. The fixed terminal <b>30</b> is provided with the fixed contact <b>31</b> at its rear end (first end) inside the sealed receptacle <b>20</b>. In addition, the fixed terminal <b>30</b> is provided with the deformation portion <b>35</b> at its front end (second end) outside the sealed receptacle <b>20</b>. The deformation portion <b>35</b> is adapted to be plastically deformed to connect the external connection terminal <b>34</b> to the fixed terminal <b>30</b>.

0115Therefore, according to the contact device <b>10</b> shown in <figref idref="f0016">FIG. 20</figref>, the external connection terminal <b>34</b> is not necessitated to be screwed to the fixed terminal <b>30</b>. Thus, the process of forming the screw hole <b>33</b> in the fixed terminal <b>30</b> can be eliminated, and therefore the production cost can be reduced. Additionally, it is possible to improve the flexibility of the design of the fixed terminal <b>30</b> because the diameter of the fixed terminal <b>30</b> is independent from the diameter of the screw hole <b>33</b>.