Electric switch

Description

FIELD OF THE INVENTION

The present invention relates to an electric switch, and in particular, to a switch for manually operated electric hand tools and devices.

BACKGROUND OF THE INVENTION

[0002] Generally, electrical switches of this type for manually operated electric tools and devices such as electric drills, cordless screwdrivers, hammer hammers, kitchen mixers or the like, include, in addition to an electrical circuit, that can be switched by an actuator that is actuated. from the outside, controlling and regulating the speed or torque of the engine. Generally, rotary or sliding potentiometers are used for this purpose. Besides controlling the speed of rotation, it is also desirable to set the direction of rotation, for example by means of a mechanical switching device. This requires a large number of contact arrangements, leading to a complex switch structure. A compact electrical switch is known from DE 10 1009 009 965 A1. In this case, the electrical components are placed on both sides of the printed circuit board as is known in the art. However, it is not preferred that the entire circuit board has to rotate in the housing to switch the direction of rotation. This imposes additional challenges on the sealing system in particular. Switches having sliding contact arrangements to produce compact electrical switches are known, for example, from EP1873800, US2006 / 243775 and US4100383.

[0003] US2006 / 0243775 A1 discloses an electrical switch for a manually operated electrical appliance according to the preamble of claim 1.

SUMMARY OF THE INVENTION

[0004] For this reason, there is a need for a compact electrical switch which at least alleviates the above drawbacks.

[0005] Accordingly, in one aspect, the present invention provides an electrical switch according to claim 1.

Advantageously, the shoe can be moved linearly along the contact surfaces in straight lines or it can be moved by a rotational movement along the contact surfaces arranged as circular shapes, the pin is linearly movable with the shoe and the protrusion provided on the pin prevents the contact system from being switched in position. turned off.

[0007] Preferably, the switch comprises a switching device for changing the direction of rotation of the electric motor and the conductive tracks are provided on the underside of the circuit board and interact with the switching device to actuate the electric motor in a selected direction of rotation.

[0008] Preferably, the switching device comprises a position encoder which can be adapted to switch between clockwise and counterclockwise rotation by means of a shifting movement or a rotation movement.

[0009] Alternatively, the switching device comprises a position encoder which is operable from the outside and a switch lever movably positioned inside the switch housing.

PZ / 5480 / JDN

Parallel to the circuit board, the switch lever is connected on one side to a position encoder and is attached on the other side by a support arm to the circuit board, the support arm forming the axis of rotation of the switch lever.

Preferably, two contact tabs are provided on the side of the switch lever facing the circuit board, the two contact tabs, in line with the axial position of the switch lever, selectively connect the conductive tracks provided on the underside of the circuit board for clockwise rotation of the electric motor or connect conductive paths for counterclockwise rotation of the electric motor.

[0011] Preferably, the switch lever is a two-arm lever having a short arm and a long arm, and the switch lever is connected at the free end of the short arm of the lever to the support arm and at the free end of the long arm of the lever to a position encoder.

[0012] Preferably, the switch housing comprises an upper cover and a lower cover which, in the collapsed position, define a common opening on the side of the switch housing wall for the plunger.

[0013] Preferably, the two covers are connected to each other by a clamping connection.

[0014] Preferably, a one-piece peripheral seal is provided between two covers of the switch housing, which seal is ring-shaped in the area of ​​the switch housing opening.

[0015] Preferably, the bottom cover has a recess for the position encoder of the switching device and the cable connection, both of which are provided with seals.

[0016] Preferably, the sealing ring is inserted into the groove of the annular recess and the multi-layer sealing package is introduced into the line connection.

Preferably, the position encoder is formed as a dial and the dial is rotatably mounted in a recess in the switch housing, a rotary actuator is provided on the outside of the dial, and the dial is torque transmitting on the inside to the switch lever.

Preferably, a tactile element is provided between the inner side of the dial and the switch lever, which tactile element interacts with the outer contour of the switch housing recess.

[0019] Preferably, a return spring installed in the switch housing engages the spindle and the spring force of said return spring acts towards the off position.

[0020] Preferably, the fixed contact is a pin attached to a printed circuit board, and the switch contact includes a pin attached to the circuit board, an arm that is a spring arm of an associated torsion spring, wherein in the engaged position, due to the spring force of a torsion spring, said spring laterally connects the contact fixed with spring arm and in which in disengaged position, a protrusion on the plunger keeps the arm of the torsion spring away from the fixed contact and prevents contact.

PZ / 5480 / JDN

EP 2 996 128 B1

INDUSTRIAL APPLICATION

[0021] The operation of the preferred embodiments will now be described to aid an understanding of the invention. The electrical switch should be used for electrical appliances, in particular for manually operated electric tools and appliances with an electric motor. These types of switches are usually referred to as trip switches and have a switch housing. Projecting from this switch housing is a pin which is connected to an actuator for manual operation of the electrical device. Actuating the actuator causes the plunger to move, namely from an initial position in which the electrical device is turned off to an on position, in which the electrical device is turned on, when this movement of the pin switches at least one contact of the contact system arranged in the switch housing. The printed circuit board is mounted fixed in the switch housing and has, in addition to two contacts of the aforementioned contact arrangement, moreover contact surfaces in the form of potentiometric circuits. According to the present invention, the contact surfaces and the two contacts of the contact array are arranged on one side of the printed circuit board, for example on the top side. The contact surfaces formed as potentiometric circuits interact with the sliding contacts which are provided on the underside of the shoe connected to the pin, such that the shoe with its sliding contacts is moved by the movement of the pin. By moving the shoe, the rotational speed or torque of the electric motor connected to the switch can be adjusted. The movement of the plunger and the slider associated therewith may be linear movement in a plane parallel to the circuit board and along contact surfaces in straight lines. Rotation is, however, also possible if the contact surfaces are arranged in circular shapes on the circuit board. By moving the pin, the contact system is also opened or closed; in this case, the working direction of the contacts similarly runs in a plane parallel to the circuit board as does the movement of the pin.

Additionally, the electric switch preferably comprises a switching device for changing the direction of rotation of the electric motor, i.e. clockwise to counterclockwise. Corresponding conductive tracks are provided on the printed circuit board for this purpose. The switching device interacts in this case with the other side of the printed circuit board, for example the bottom side, on which the corresponding conductive tracks are provided.

[0023] In an embodiment of the invention, by actuating the pin, it is moved from its off position to its on position, and thus a connection is established between the switch contact and the fixed contact of the contact array provided in the switch housing. In the pin off position, the protrusion provided on the pin prevents the contact system from connecting. In an embodiment of this type, the contact arrangement consists of a pin attached to the circuit board as a fixed contact and a pin similarly attached to the circuit board, however, in this case with an associated torsion spring as the switch contact. In the off position, the protrusion on the plunger prevents the free arm of the switch contact torsion spring from making contact with the fixed contact. The spindle protrusion keeps the arm of the switch contact torsion spring away from the fixed contact. On the contrary, in the engaged position, due to the preferably linear movement of the plunger, its projection is also displaced from the contact of the switch and the arm of the torsion spring is released and may, due to

PZ / 5480 / JDN

The spring force of the torsion spring moves towards and contacts the fixed contact, preferably laterally. The torsion spring arm in this case moves in a plane parallel to the circuit board.

Additionally, the movement of the plunger also controls the rotational speed or torque of the electric motor, since the sliding contacts provided on the plunger shoe interact with PCB contact surfaces formed as potentiometric circuits and because the resistance changes due to changes in the adjustment distance of the sliding contact on the plunger. of the contact surface, for example, the rotational speed of the electric motor can be regulated in this way. Thus, on the one hand, the pin causes contact to activate the electric motor and at the same time to adjust the speed of rotation. This is possible due to the special design of the pin with the projection and the slider, with the arrangement of the contacts of the contact system and the contact surface provided on one side, for example on the top side, of the printed circuit board in the form of potentiometric circuits.

[0025] The other side of the printed circuit board is in contact with the switch device. This switching device also has an externally accessible actuator for setting a clockwise or counterclockwise rotation of the electric motor. This setting may be performed by linear sliding movement of the actuator or by rotational movement. The actuator is preferably a position encoder which allows external operation and is adjustable by rotation, and which is connected to an actuating lever arranged inside the switch housing. The position encoder is mounted in a recess in the housing. In a preferred embodiment, the outer part of the position encoder is shaped as a disc and the disc is rotatably mounted in a circular recess in the switch housing in which a pusher is provided for rotational actuation on the outside of the disc, which pusher interacts with, for example, a manually operated direction switch. electrical appliance. When actuating the rotating disc of the position encoder, torque is transmitted to the shift lever provided inside the switch housing, which switch lever is connected on one side to the position encoder and on the other side to a support arm attached to the circuit board and installed with the support arm. to the circuit board. This support arm thus forms the axis of rotation of the shift lever. The shift lever is arranged parallel to the circuit board and can be moved in this plane by axial movement into at least two positions. According to the axial position of the shift lever, the contact tabs which are provided on the shift lever connect either circuit paths of the circuit board for clockwise rotation of the electric motor, or alternatively the contact tabs establish bridge contact for the circuit path for counterclockwise rotation. the electric motor rotation clock.

[0026] In a particularly preferred embodiment, the position encoder also comprises a tactile element. The tactile element interacts with the circumferential contour of the recess of the switch housing, which contour has engagement positions corresponding to different positions of the shift lever.

[0027] The previously described electrical switch has been designed very compactly as both sides of the printed circuit board are accessible for the various functions of the switch and the printed circuit board is housed fixed in the housing. This makes it easier to seal an electrical switch of this type. In an embodiment of the invention, the switch housing consists of two covers

PZ / 5480 / JDN

EP 2 996 128 B1 for easier assembly, namely top cover and bottom cover. These covers are preferably connected to each other by means of a clamping connection. In the collapsed position, both covers define the boundary of a common pin hole on the side wall. To seal the switch housing, a one-piece peripheral seal is provided between the covers of the switch housing, which seal is formed as a ring in the spindle bore region. Additional openings in the switch housing may likewise be sealed in a simple manner, thus, for example, an annular groove may be provided in a recess for a disc-shaped position encoder into which groove the sealing ring will be inserted. For the necessary wire connection in the switch housing, i.e. for the electric wire that leads to the electric motor, a multi-layer sealing package, for example, can be used.

[0028] The switches of the invention are particularly used for use with electrical appliances using electrically commutated motors such as brushless direct current motors (BLDC) and brushless alternating current motors (BLAC).

BRIEF DESCRIPTION OF THE DRAWING

[0029] A preferred embodiment of the invention will now be described by means of examples only with reference to the figures of the accompanying drawing. In the figures, identical structures, elements or parts which appear in more than one figure are generally designated with the same reference number in all figures in which they appear. The dimensions of the components and features shown in the figures are generally selected for convenience and clarity of presentation and need not be shown to scale. The figures are listed below.

Figure 1 is a perspective view of an electrical switch according to a preferred embodiment of the present invention;

Figure 2 is a perspective view of the switch of Figure 1 in another aspect with the top cover raised;

Figure 3 is a partial exploded view of the switch;

Figure 4 shows the circuit board of the switch;

Figure 5 is a plan view of the printed circuit board of Figure 4;

Figure 6 is a perspective view of the circuit board in another aspect;

Figure 7 is a view of the underside of the printed circuit board of Figure 4;

Figure 8 shows the toggle device of the switch in a position for anticlockwise rotation of the motor;

Figure 9 shows the toggle device of the switch in a position for clockwise rotation of the motor;

Figure 10 is a perspective view of part of the switch of Figure 1 in an engaged position; and

Figure 11 is a view similar to Figure 10 with the switch in the off position.

PZ / 5480 / JDN

EP 2 996 128 B1

DETAILED DESCRIPTION OF PREFERRED EXAMPLES

[0030] The drawing shows a preferred embodiment of an electric switch 1 according to the invention, which can be applied to hand-operated electric tools and appliances with an electric motor, for example electric drills, cordless screwdrivers, hammer hammers, kitchen mixers and the like. To this end, this electric switch 1 is integrated into the tool housing and the pin 13 is connected, for example, to a manually actuated actuator by means of connection 2. In addition to the switch 1 at the line connection 17, a corresponding electric cable (not shown in the drawing) extends. ) for connection to an electric motor. The switching device 40, which is installed in the switch housing 10 of the electric switch 1, is externally movable by a pusher 47, determines the direction of rotation of the electric motor, and operates together, for example, with a corresponding shift lever in the electric tool. The shift lever is movable from the outside. For manually operated electrical devices where there is no need to provide a different direction of rotation of the electric motor, the switching device 40 may be omitted.

[0031] The switch housing 10 of the electric switch 1 shown in Figure 1 includes two covers, namely a first or top cover 11 and a second or bottom cover 12. This should be understood from Figure 2 and Figure 3, in which the electric switch 1 is shown from two sides, in any case with the switch casing open 10. A good sealing of the switch 1 can be understood from these figures. Thus, a one-piece peripheral seal 50 is provided between the covers 11 and 12 and extends over the edges of the covers 11 and 12 and includes a ring 51 in the area of ​​the opening 19. The opening 19 is formed by two covers 11 and 12. An opening 19 is provided for the pin 13. which protrudes from the housing 10 of the switch housing 10 of the switch 1 as shown in Figure 1. Inside the switch housing 10, pin 13 is connected to a shoe 15 which is arranged to be movable, in this case by a linear translational movement, over a printed circuit board 30 positioned secured in the switch housing 10. The pin 13 can be actuated by an actuator. which is moved to the switch housing 10. With this sliding movement of the pin 13, the shoe 15 connected to the pin 13 is moved and, during this movement, interacts with its sliding contact 16 on the contact surfaces 33, 34 on the top side 31 of the circuit board 30. The sliding contact 16 can be better understood from 4 and 5, as the printed circuit board 30 is shown on the one hand in perspective and without housing, and on the other hand as a top side view 31 of the printed circuit board 30. Sliding contact 16 is provided on the side of the slider 15 facing the printed circuit board (not shown in Figures 4 and 5). The ends of the contacts 16a, 16b come into contact with the contact surfaces 33, 34 on the upper side 31 of the circuit board 30. Due to the resilient U-shape of the sliding contact 16, sufficient contact pressure is ensured. During the movement of the pin 13, the slider 15 moves along the printed circuit board 30, i.e. along the surfaces of contacts 33, 34 formed as potentiometric circuits. The resistance, and thus the rotational speed or torque of the electric motor connected to the switch 1, changes with the displacement path of the sliding contact 16.

The contact arrangement 20 is also provided adjacent the contact surfaces 33, 34 on the upper side 31 of the printed circuit board 30. It includes, as can be seen in Figure 4, a fixed contact 21, shaped as a pin and secured to the printed circuit board 30, and switch contact 22. Contact

PZ / 5480 / JDN

The switch 22 similarly includes a pin attached to the circuit board 30 and a torsion spring 23. If, for example, the direction of rotation for the electric motor has been set by the position encoder 45 and pin 13 has been moved by the actuator from its off position, shown in Figure 11, to its attached position shown in Figure 10, i.e. displaced into the housing of the switch 10, the protrusion 14 provided on the pin 13 is also displaced by this movement. This protrusion 14 abuts, in the disengaged position as shown in Figure 11, against the end of arm 24 of the torsion spring 23 of the contact switch 22 and keeps said arm at a distance from the fixed contact 21. If the protrusion 14 is now also moved away from the arm 24 by the displacement of the pin 13, said arm can now press against the fixed contact 21 laterally due to the elastic force of the torsion spring 23, thereby activating the electric motor. The movement of the arm 24 of the torsion spring 23, and thus the operating direction for opening and closing of the contact system 20, is in a plane parallel to and above the circuit board 30. In this case, the pin 13 is spring loaded, in this example. The return spring 60 acts to automatically return the spindle 13 to the off position as soon as no pressure is exerted on the spindle 13 by an actuator (not shown).

[0033] On the opposite side, the lower side 32 of the PCB 30, the conductive tracks 35, 36 provided on the PCB 30 are in operative connection with the switch lever 42 of the switching device 40. The switch lever 42 extends in a plane parallel to the PCB. 30 as can be seen in Figure 6. The shift lever 42 is rotatable in this parallel plane about a pivot axis formed by the support arm 41 beneath the circuit board 30. The support arm 41 is connected to the circuit board 30 and supports the switch lever 42. On the lower side of the switch lever 42, contact tabs 43, 44 are provided which either bridge contact for conductive path 35 for counterclockwise rotation of the electric motor, or alternatively bridge contact for conductive path 36 for clockwise rotation. rotation of the electric motor. To change the direction of rotation, the switch lever 42 is turned. To this end, the switch lever 42 is connected to the position encoder 45 of the switching device 40, as can be better seen in Figures 8 and 9. In this embodiment, the switch lever 42 is formed as a double-arm lever. The short arm of the lever 42a is fixed at its free end on the support arm 41 and the free end of the long arm 42b of the switch lever 42 is connected to the position encoder 45. In this case, the switch lever 42 is connected by a connecting piece 49 (see Figure 9) to the touch element 48 of the position encoder 45. Disc 46 of the position encoder 45 is disposed outside the switch housing, said disc being fitted together with the touch element 48 in the recess 18. switch housing 10, as may be understood from Figure 3. A pusher 47 is provided on the outer side of disc 46, which pusher extends directly from the electrical appliance housing, or is preferably connected to an externally adjustable switch lever. To switch the direction of rotation of the electric motor, i.e. to set a clockwise or counterclockwise rotation of the electric motor, the follower 47 is moved. The disc 46 performs, together with the touch element 48 in the recess 18, a rotational movement. In this way, the touch element 48 interacts with the circumferential contour 18a of the recess 18. The touch element 48 is in this case connected by a pivoting attachment to the disc 46, e.g.

PZ / 5480 / JDN

An indentation shaped to the head of the touch element 48 engages a recess with a shape corresponding to the head of the touch element 48 on the lower side of the dial 46, engaging a recess with a shape, e.g. a square recess. side of the touch element 48 laterally from the touch element and engages the outer contour 18a of the recess 18. If, for example, the follower 47 is moved, so that the disc 46 rotates and the tactile 48, due to the pivotally mounted connection, is also moved, the laterally spring-loaded ball is pressed against the tactile 48 up to a certain rotating path. the ball will again find space in a corresponding recess in outer contour 18a. The outer contour 18a of the recess 18 is particularly shaped such that it takes place at two switch positions of the switch lever 42. The touch element 48 preferably has on two opposite sides a ball, respectively, extending laterally from the touch element 48, which balls are pressed outwardly by the joint. spring. This enhances the tactile sensation. Two different positions of the switch of the switch lever 42, i.e. two different positions of the position encoder 45 are shown in Figures 8 and 9. The potential direction of movement of the position encoder 45 is indicated by an arrow.

Access to the position encoder 45 in the switch housing 10 is sealed by a sealing ring 52, which is preferably seated in the groove of the annular recess 18. The wire connection 17 is provided in the switch housing 10, namely in the lower cover 12 of the switch housing 10, as adjacent. with a position encoder 45, the wire connection leading all wires (not shown) together from the switch housing 10. For sealing, a sealing packet 53 is provided, shown in Figure 3, which surrounds the conduit with multiple layers of sealing.

[0035] In the description and claims of the present application, each of the verbs "comprises", "comprises", "has" and "has" and their conjugates, is used inclusively to specify the presence of said object or feature, but not to exclude the presence of said object or feature. additional objects or features.

[0036] It should be noted that certain features of the invention which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Rather, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

[0037] The embodiments described above are provided by way of example only and various different modifications will be apparent to those skilled in the art without departing from the scope of the invention as defined by the appended claims.

PZ / 5480 / JDN

EP 2 996 128 B1