Contact unit for electromagnetic relays

To increase the contact reliability of the electromagnetic relay It is, for example, from DE-C-32 24 013., the contact spring by to provide a longitudinal slot with two resilient ends and each end be equipped with a contact piece with a corresponding counter contact piece together working on a common fixed contact. The probability that both contact pairs impurities as a result of failure by the smallest fibers, injection burrs or the like, is much lower than with single contacts.

In such "twin" -Kontaktfedern as similarly also known from DE-B-11 75 807, DE-U-94 04 775 and DE-C-972 072 are known, but there is a Difficulty that the spring arms formed by the longitudinal slot easier break than the undivided spring. In such a case, although the relay is se still functional, the broken arm but can unforeseen short circuits lead. Another problem of the known Twin-contact spring is that the individual spring arms much softer than the undivided spring, so that when a contact is welded the corresponding arm is not sufficiently stiff to the actuator hold in the closed contact position. For these reasons, is the use of the known twin contact springs with safety relay not permitted.

From DE-C-32 24 468, a contact arrangement is known in which the Contact spring two cooperating with separate fixed contacts contacts wearing. Apart from the fact that with such bridge contacts the total contact resistance is twice as high as with a single contact, not increase this arrangement, the security of the contact-making but the contact opening.

also so-called "crown contacts" are known, in which at least one of two interacting contact rivets a raised comprising edge so that, when a limited mutual displacement of the two rivets two contact points arise. Except that the thus formed Contact points are very small areas, the raised edge uses the Operating relatively rapidly, so that the intended double contact action quickly lost.

DE-A-32 24 468 shows an arrangement in which the contact points two fixed contacts with a common contact point of a bridge contact spring Collaborate.

A contact unit with the features specified in the preamble of claim 1 Features is known from DE-U-90 15 406..

The invention is based on the task, a contact unit provide that the reliability of the contact with safety relays, ie Relay with forcibly guided contacts, increased.

The inventive solution to this problem is characterized in claim. 1

When subsequently designed contact unit are on the contact spring two contact points are provided, transversely to the longitudinal extension of the contact spring are arranged with the same fixed contact or with this Collaborate provided counter-contact points, the two Contact points on the contact spring and / or the fixed contact in the form a common contact piece are formed. The fact that the Contact spring in at least one region is not only flexible, but has also increased about its longitudinal torsion, ensures that both contact pairs and then close when the contact pieces -bearing free end of the contact spring is not parallel to the counter-contacts carrying fixed contact extends.

In contrast to the above-mentioned twin-contact spring is in the inventive contact unit the contact spring continuously in their obtain one-piece mold so that spring breakage is less likely and possibly to a complete failure of the relay by interrupting leads.

Advantageous configurations of the region of enhanced torsional are given in claim 2nd

With the developments of the invention according to claims 3 to 6 can be a positive guidance of the contact spring by the operator, in particular when opening, reach.

The design of the contact spring leading actuator according to the Claims 7 and 8 is appropriate for the relay according to the invention for the typical torsional behavior of the contact spring effectively exploit.

In the development of the invention of claim 9 is the contact unit formed so that the contact spring against the fixed contact is inclined so that a first closing and last opening precontact and last closing and first opening the main contact occur. This design has the advantage of a softer contact is reduced Bounce behavior.

In the embodiment of the invention according to claims 10 to 12 the first closing and last opening contact pair with a Last Contact expedient features fitted, while the other Contact pair the qualities of a signal contact having.

An embodiment of the invention is described below with reference to the Drawings explained; shows it<dl tsize="7"><dt>figure 1</dt><dd>a schematic representation of a contact unit in Side View,</dd><dt>figure 2</dt><dd>an end view along the arrow II of Figure 1,</dd><dt>figure 3</dt><dd>a perspective view of a part of an electromagnetic Relay with a contact unit according to Figure 2,</dd><dt>figure 4</dt><dd>a similar to Figure 1 showing the check with the relay Figure 3 used Contact unit</dd><dt>figure 5</dt><dd>an end view of the actuator in the arrangement of Figure 3 with a contact spring,</dd><dt>figure 6</dt><dd>an enlarged view of a portion of Figure 5, and</dd><dt>figure 7</dt><dd>an embodiment of an inventive contact arrangement in Figure 2 corresponding schematic Representation.</dd></dl>

Figures 1 to 6 are illustrative; they do not show the invention Contact arrangements.

The contact unit shown in the figure 1 and 2 consists essentially from a contact spring <b>10,</b> with its one end to a carrier <b>11</b> fixed, approximately riveted, is a the free end of the contact spring<b>10</b> opposing fixed contact <b>12</b> and a on the contact spring<b>10</b> acting actuator <b>13,</b> the in the adopted here Embodiment with an indicated in Figure 2 relay armature <b>14</b>coupled.

That the fixed contact <b>12</b> opposing free end of the contact spring<b>10</b> is widened towards their body and carries two contact pieces<b>15, 16,</b> transversely to the longitudinal extension of the contact spring <b>10</b> side by side (In the drawing with each other) are arranged. Likewise, the hard Contact <b>12</b> with two contact pieces <b>17, 18</b> provided that the contact pieces<b>15, 16</b> of the contact spring <b>10</b> facing and each with these Collaborate.

As seen in Figure 2, is the free end of the contact spring <b>10</b>at an angle to the fixed contact <b>12,</b> so that the contact pieces<b>15, 16</b> of the contact spring <b>10</b> straight line connecting the contact pieces <b>17, 18</b> of the fixed contact <b>12</b> straight line connecting at an acute angle cuts. This inclination of the free end of the contact spring<b>10</b>arises from the fact that the contact spring in between her fixed and free end located torsion <b>19</b> about its longitudinal axis is vortordiert.

The actuator <b>13</b> is arranged and configured so that it on the contact spring<b>10</b> near the free end of attacks and opposite with two Surfaces of the contact spring <b>10</b> engageable. Here, the contact areas <b>20, 21</b> the actuator <b>13</b> in the direction of the respective surface of the contact spring <b>10</b> convex.

If during operation of the relay armature <b>14</b> in the direction of arrow A actuated, it moves the actuator <b>13</b> by in Figure 2 right. Figure 2 shows the moment in which the upper contact piece <b>15</b> of the contact spring <b>10</b> the contact piece <b>17</b> of the fixed contact <b>12</b> just touches. Upon further movement the actuator <b>13</b> right swings in Figure 2, the front end of the contact spring <b>10</b> to the point of contact between the contact pieces<b>15</b> and <b>17,</b> this pivoting movement by an adequately dimensioned Torsional flexibility of the torsion <b>19</b> is ensured, until the lower contacts <b>16, 18</b> touching each other. The subsequent further Movement of the operated <b>13</b> right up in Figure 2 to the end position armature <b>14</b> now causes the fixed contact <b>12</b> deflected and thereby the will contact force increases at the two contact pairs.

During the described pivotal movement of the contact pieces<b>15, 16</b> supporting the free end of the contact spring <b>10</b> deploying them to the convex contact area <b>20</b> the actuator <b>13</b> from.

To open the relay armature <b>14</b> moves in the direction of arrow B, so that now the opposite contact area <b>21</b> the actuator<b>13</b> with the other face of the contact spring <b>10</b> engages and causing the contact pieces <b>15, 16</b> of the contact spring <b>10</b> of the contact pieces<b>17, 18</b> of the fixed contact <b>12</b> be lifted. It opens first the lower contact pair <b>16, 18</b> and then the upper contact pair<b>15, 17th</b>

In the illustrated operation forms the upper contact pair <b>15, 17</b> a pre-contact and the lower contact pair <b>16, 18</b> a main contact. Since the first closing and last opening precontact a load contact forms and quickly wears out, is as shown in Figure 1, the contact piece<b>15</b> larger dimensions than to the main or signal contact associated contact piece <b>16th</b> Furthermore, the contacts are made <b>15, 17</b>the pre-contact of baser material as the contact pieces <b>16, 18</b>of the main contact. For example, the contact pieces<b>15, 17</b> out AgSnO and the contact pieces <b>16, 18</b> consist of a AuAg Alloy.

Instead of the above-mentioned Vortordierung of the torsion <b>19</b>to achieve the inclination illustrated in Figure 2 Free End of the contact spring <b>10</b> opposite the fixed contact <b>12</b> can be the same Operation by tilting the fixed contact <b>12</b> to accomplish or by tilting the carrier <b>11</b> together with the contact spring<b>10,</b> which in the rest position is precisely in this case.

This in the perspective view of Figure 3 (omitting the housing cap) comprises partially shown electromagnetic relay a base body <b>22,</b> from which a yoke leg <b>23</b> of a (not shown) coil passing through the yoke protrudes. The yoke leg<b>23</b> is between the two arms of this embodiment, generally H-shaped armature relay <b>14,</b> about a vertical center axis at one on the basic body <b>22</b> mounted trunnion <b>24</b> swiveling is mounted.

The one with the relay armature <b>14</b> coupled actuator <b>13</b> is of the basic body <b>22</b> formed guide columns <b>25</b> displaceable in its plane guided and engages, as illustrated in detail in FIG 4 to 6, the contact spring <b>10,</b> whose contact pieces <b>15, 16</b> with the fixed contact <b>12</b>mounted contact pieces <b>17, 18</b> Collaborate. In Figure 3, the Relay with two contact springs <b>10</b> shown assembled. pins<b>26</b> of the fixed contacts <b>12</b> protrude from the base body <b>22</b> after out below.

In the contact spring shown in more detail in Figure 4 <b>10</b> the torsion<b>19</b> realized by reducing the width of the spring. Alternatively or additionally, to the spring <b>10</b> in this area <b>19</b> also in its material thickness be reduced or treated in any other way, the torsional to increase.

As shown, there is the area <b>19</b> between the contact carrier<b>11</b> riveted fixed end of the contact spring <b>10</b> and the engagement area the actuator <b>. 13</b> The contact spring <b>10</b> has in this application area and at its fixed end their full width at the free end is further increased to between the contacts <b>15</b> and <b>16</b> enough to create distance. The actuator<b>13</b> engages the contact spring <b>10</b> in a stiffened area.

As shown in Figure 5 and the partial enlargement of Figure 6, extends the contact spring <b>10</b> between the two contact areas <b>20, 21</b>the actuator <b>13,</b> of which the area <b>20</b> designed convex or spherical is, when pressed to the contact spring <b>10</b> pivoting about its longitudinal center axis permit and thus making contact on both contact pairs<b>15, 17</b> and <b>16, 18</b> to ensure. In the opposite contact area<b>21,</b> of the contact spring <b>10</b> passes when opening in contact, is a convex or spherical design is not required. If the contact spring <b>10</b> is biased into the closed position, to the opening at their abutting surface <b>21</b> the actuator <b>13</b> be crowned.

In the inventive embodiment illustrated in Figure 7 are both on the fixed contact <b>12</b> situated contact points on a common contact piece <b>27</b> formed whose contact surface dimensioned so is that with the two separate contact pieces <b>15</b> and <b>16</b> of the can work together contact spring. To correct contact even when of twisted contact spring <b>10</b> or a tilted fixed contact <b>12</b>enable is the contact surface of the common contact piece <b>27</b>spherically shaped.

Instead of the embodiment shown in Figure 7, it is also possible, on the contact spring <b>10</b> provide a large common contact piece and with two separate contact pieces on the fixed contact <b>12</b> cooperate allow.

Another conceivable alternative is to both of the contact spring<b>10</b> and the fixed contact <b>12</b> a single continuous contact piece arranging and at least one of them with two projections to provide for the generation of two spatially separated points of contact.

As further shown in Figure 7, the contact spring <b>10</b> in the direction its longitudinal central axis with a bead <b>28</b> provided that the rigidity contact spring <b>10</b> in their longitudinal direction in the area between the contact pieces<b>15, 16</b> and the engagement area of ​​the actuator <b>13</b> enlarged.

Instead of the bead shown <b>28</b> can be a stiffening of the contact spring<b>10</b> by increasing its thickness in the area between the contact pieces<b>15, 16</b> and the engagement area of ​​the actuator <b>13</b> achieve.

If the reinforcement in the bead shown in Figure 7 <b>28,</b> so can this over the entire length of the contact spring <b>10</b> up to her on the contact carrier<b>10</b> go through the fixed end; in such a direction of the longitudinal center axis and thus in the neutral zone of the contact spring <b>10</b> extending Beading <b>28</b> Although resulting in a reduced flexibility in the area<b>19,</b> but affects the torsion in this area only slightly.

LIST OF REFERENCE NUMBERS

<dl tsize="6" compact="compact"><dt><b>10</b></dt><dd>contact spring</dd><dt><b>11</b></dt><dd>support for <b>10</b></dd><dt><b>12</b></dt><dd>hard Contact</dd><dt><b>13</b></dt><dd>actuator</dd><dt><b>14</b></dt><dd>relay armature</dd><dt><b>15, 16</b></dt><dd>Contacts at <b>10</b></dd><dt><b>17, 18</b></dt><dd>Contacts at <b>12</b></dd><dt><b>19</b></dt><dd>torsion of <b>10</b></dd><dt><b>20, 21</b></dt><dd>Contact regions in <b>13</b></dd><dt><b>22</b></dt><dd>basic body</dd><dt><b>23</b></dt><dd>yoke leg</dd><dt><b>24</b></dt><dd>pivot</dd><dt><b>25</b></dt><dd>guide columns</dd><dt><b>26</b></dt><dd>pins</dd><dt><b>27</b></dt><dd>common contact piece</dd><dt><b>28</b></dt><dd>Beading</dd></dl>