Mains-powered hand tool

Abstract

Mains-operated hand tool (10) with a tool housing (12) in which an electric drive motor (28) for driving an associated tool (40) is arranged, wherein a slide switch (24) coupled to a sliding element (30, 106, 204, 504, 604) for switching the drive motor (28) on and off is arranged at least longitudinally displaceable on the tool housing (12), characterized in that a protective device (100, 200, 500, 600) with an electromechanical relay (104, 300, 400, 502, 602) is provided, which is designed to prevent an uncontrolled restart of the drive motor (28) after an interruption of the corresponding power supply to the drive motor (28) by means of the electromechanical relay (104, 300, 400, 502, 602). to prevent the self-holding of the relay (104, 300, 400, 502, 602) from being released, whereby a working contact of the relay (104, 300, 400, 502,602) opens and the working contact of the electrical switch is open or the normally closed contact of the electrical switch is closed, wherein the slide switch (24) is tiltably mounted on the slide member (30, 106, 204, 504, 604) and can be locked to the tool housing (12) in an operating position when the drive motor (28) is switched on, wherein the protective device (100, 200) has an electrical switch (102, 202) with a working contact (112, 212) and a normally closed contact (114, 214), wherein the working contact (112) and the normally closed contact (114) can be actuated by means of a lever (130) tiltably mounted on the plunger (108), wherein the lever is guided circumferentially in a cam track (132) with an approximately square plan and the cam track (132) has at least one diagonally extending track section (136) shows.

Description

State of the art

[0001] The present invention relates to a mains-operated handheld power tool with a tool housing in which an electric drive motor is arranged for driving an associated insert tool. A slide switch coupled to a slide member for switching the drive motor on and off is arranged on the tool housing in an at least longitudinally displaceable manner. Starting from the operating position, the slide switch can be moved into a blocking position, in which it is mechanically locked to the tool housing, thus eliminating the need for the user to continuously hold or hold the slide switch during operation of the handheld power tool.

[0002] Such hand tools are already known from the documents DE 60 2004 013 191 T2, DE 26 16 554 C2, US 6 469 268 B1, US 5 525 948 A, US 5 401928 A and US 4 401 958 A.

[0003] A disadvantage of the state of the art is that the locking mechanism of the slide switch on the tool housing of such a handheld power tool is purely mechanical. This can lead to an uncontrolled, automatic restart of the drive motor after a malfunction occurs during operation of the handheld power tool—for example, after a brief power interruption—and thus, for example, to injury to the user or damage to an associated tool. Disclosure of the invention

[0004] An object of the invention is therefore to provide a new mains-operated hand-held power tool in which a restart of an associated drive motor after an interruption of an associated power supply can be excluded in a structurally particularly simple, reliable and cost-effective manner.

[0005] This problem is solved by a mains-operated hand-held power tool with a tool housing in which an electric drive motor is arranged for driving an associated insert tool, wherein a slide switch, coupled to a slide member, for switching the drive motor on and off is arranged on the tool housing in an at least longitudinally displaceable manner. A protective device with an electromechanical relay is provided, which is designed to prevent, by means of the electromechanical relay, an uncontrolled restart of the drive motor after an interruption of a corresponding power supply to the drive motor by canceling a self-holding of the relay.

[0006] The invention thus enables the provision of a mains-operated or mains-fed handheld power tool in which restarting of the drive motor after a power failure is impossible, even when the slide switch is locked to the tool housing. This significantly reduces the risk of accidents for a user and prevents damage to an associated tool.

[0007] According to the invention, the slide switch is tiltably mounted on the sliding member and can be locked to the tool housing in an operating position when the drive motor is switched on.

[0008] This provides additional mechanical positioning security for the slide switch when the drive motor is switched on by axially moving the slide switch. Preferably, the slide switch is mounted on the sliding element with a spring-loaded tilt mechanism.

[0009] In a first and second embodiment, the protective device each has an electrical switch with a make contact and a break contact.

[0010] This enables simple and reliable electrical control of the relay.

[0011] Preferably, the electrical switch has a plunger pre-tensioned by a compression spring, which is axially displaceable by means of the sliding member against a spring force applied by the compression spring.

[0012] This allows the mechanically unloaded plunger to automatically return to its rest position.

[0013] According to the invention, the working contact and the rest contact can be actuated by means of a lever which is tiltably mounted on the plunger, wherein the lever is guided in a sliding track with an approximately square outline and the sliding track has at least one diagonally running track section.

[0014] This allows a simple and uncomplicated connection to be created between the mechanical slide switch and the electrical switch coupled to it for switching the drive motor on and off via the relay, while also ensuring that the working contact of the electrical switch is always actuated before its rest contact.

[0015] Preferably, the working contact can be closed at least briefly by axially actuating the plunger from a rest position in order to put the relay into self-locking mode and to switch on the drive motor, wherein the plunger remains in a depressed position.

[0016] As a result, the motor current flows primarily via a working contact of the relay and only briefly via the working contact of the switch.

[0017] Preferably, the break contact can be opened by a further axial actuation of the plunger to switch off the drive motor in order to cancel the self-holding of the relay, wherein the plunger is urged back into its rest position by means of the spring force of the compression spring.

[0018] This means that even a brief activation of the normally closed contact by means of the plunger, which is mechanically coupled to the slide switch via the sliding element, is sufficient to permanently deactivate the drive motor by the user. Even in the event of a power interruption, the self-locking function is canceled, as the normally open contact of the relay opens due to the coil then also being de-energized, and the normally open contact of the electrical switch is open or the normally closed contact of the electrical switch is closed, reliably preventing the drive motor from restarting, even with the slide switch usually locked in this configuration.

[0019] In the case of the second embodiment, the electrical switch has a plunger prestressed by a compression spring with an actuating hook, wherein the plunger is axially displaceable by means of the sliding member against a spring force applied by the compression spring.

[0020] The actuating hook ensures reliable actuation of the normally open and normally closed contacts within the electrical switch.

[0021] Preferably, the actuating hook is arranged in the area between the working contact and the resting contact of the electrical switch in order to enable alternating actuation of the working contact and the resting contact.

[0022] This prevents the simultaneous operation of the normally open and normally closed contacts within the electrical switch.

[0023] Preferably, the make contact is open in a latched operating state of the slide switch and the break contact is closed, whereby the drive motor is switched on by the self-holding of the relay.

[0024] This means that even a brief closure of the make contact is sufficient to permanently switch on the drive motor. In the event of a power failure, the relay's self-locking function is canceled, shutting off the drive motor. Uncontrolled restart of the drive motor is impossible when the power is restored, even if the slide switch is mechanically locked to the tool housing, because the make contact of the electrical switch is open and the break contact of the electrical switch is closed.

[0025] In the case of a third and fourth embodiment of the protective device, the sliding member is pre-tensioned by means of a compression spring supported on the tool housing.

[0026] This can replace the effect of the compression spring otherwise provided in the electrical switch.

[0027] Preferably, by means of the sliding member, a contact slide within the relay can be displaced with play parallel to the sliding member in order to energize a coil of the relay by forced mechanical closing of a working contact of the relay.

[0028] In this way, the relay takes over at least part of the function of the otherwise necessary electrical switch.

[0029] Preferably, the relay for self-holding has an angled armature which is mounted tiltably within the relay and has a first and a second leg, wherein by energizing the coil, the first leg is magnetically attracted to it in such a way that, in the energized state of the coil, the working contact of the relay can be mechanically held in the closed switching state by means of the second leg.

[0030] This allows the relay to be latched and the power tool's drive motor to be switched on with just one relay contact. The armature acts as a mechanical holding element for the relay's contact when closed.

[0031] According to the fourth embodiment, the relay has a coil and a plate-shaped armature which can be magnetically attracted by the coil, and a working contact of the relay can be actuated by means of the armature.

[0032] This results in a simplified design of the relay's armature, which eliminates the need for its mechanical holding function and a pivoting bearing on the relay coil.

[0033] Preferably, a plunger protruding from the relay for actuating the armature can be displaced with play parallel to the sliding member by means of the sliding member.

[0034] This ensures reliable actuation of the armature for mechanically forced closing of the relay's working contact while maintaining the traditional movement sequence of the sliding element.

[0035] Preferably, the plunger is sealed from a housing of the relay by means of a sealing element.

[0036] This prevents the penetration of foreign particles into the relay housing, resulting in perfect electrical function of the relay's working contact without a significant increase in the actuating forces, even under problematic environmental conditions.

[0037] Preferably, by mechanically forced actuation of the plunger by means of the sliding member, a working contact of the relay can be closed and the coil of the relay can be energized in order to switch on the drive motor and to put the relay into self-holding mode.

[0038] This ensures that the drive motor is switched on permanently by simply pressing the slide switch once, while at the same time the relay's self-holding function provides restart protection in the event of a power failure.

[0039] Preferably, the relay is identical in terms of its external geometry to a standard electrical switch for switching the drive motor of the hand-held power tool on and off.

[0040] This means that the relay can be easily replaced with the standard switch otherwise used in large-scale production of the hand-held power tool, largely at no cost and without any tool modifications. Short description of the drawings

[0041] The invention is explained in more detail in the following description using exemplary embodiments illustrated in the drawings. They show: Fig. 1 a perspective view of a hand-held power tool with a slide switch for switching an associated drive motor on and off, Fig. 2 a perspective view of the slide switch of Fig. 1 with an associated sliding element and with a first embodiment of a protective device comprising a relay and an electrical switch according to a first embodiment, Fig. 3 an electrical diagram of the protective device of Fig. 2, Fig. 4A is a perspective, at least partially transparent view of the electrical switch of the protective device of Fig. 2, Fig. 4B-4E Views of four different electrical switching states of the electrical switch of Fig. 4A, Fig. 5A is a plan view of a protective device according to a second embodiment, with an electrical switch according to a second embodiment, Fig. 5B-5E Side views of the protective device of Fig. 5A with four different electrical switching states of the electrical switch of Fig. 5A, Fig. 6, Fig. 7 two circuit diagrams of a third and fourth embodiment of a protective device, Fig. 8A is a side view of the third embodiment of a protective device, Fig. 8B-8F Side views of the third embodiment of the protective device of Fig. 8A with four different electrical switching states of an associated relay, Fig. 9A is a side view of the fourth embodiment of a protective device, and Fig. 9B-9F Side views of the fourth embodiment of the protective device of Fig. 9A with four different electrical switching states of an associated relay. Description of the embodiments

[0042] Fig. 1 shows an exemplary mains-operated or mains-fed handheld power tool 10, the power supply of which is preferably via a power cable 26. The handheld power tool 10 has an illustratively at least approximately cylindrical tool housing 12, which preferably forms at least in section a handle 14, on which, for example, a rubberized gripping surface 16 is provided, and further preferably forms at least one further gripping area 18. On a housing side 20 of the handle 14, which illustratively has a longitudinal axis 22, a mechanically acting slide switch 24 is provided, which is longitudinally displaceable in the direction of the longitudinal axis 22. By actuating the slide switch 24, a user can switch an electric drive motor 28 of the handheld power tool 10, arranged in the tool housing 12, on and off.By means of a protective device 32 which is mechanically coupled to the slide switch 24 via a sliding element 30, in addition to the switching on and off functionality for the drive motor 28, an uncontrolled restart of the drive motor 28 after an interruption of the power supply is also realized, regardless of the actuation state of the slide switch 24.

[0043] The hand-held power tool 10 is illustrated here in the manner of a hand-held reciprocating or pendulum reciprocating saw 34, wherein the drive motor 28 can be any desired motor type, e.g., an electronically commutated motor or a DC motor. The drive motor 28 serves to drive an output shaft 36, on which, for example, a tool holder 38 is arranged and which serves to hold an insert tool 40 that can be driven in a reciprocating manner, e.g., a saw blade 42. This insert tool 40 is arranged, for example, at least approximately perpendicular to a base plate 44 fastened to the tool housing 12 and, for example, extends through a recess 46 provided in the base plate 44. In addition, an optional suction device 48, which is connected to a suction hose 50, is arranged on the base plate 44, for example. It should be noted, however, that the function and structure of a suitable drive motor 28 ora suitable reciprocating or pendulum reciprocating saw 34 are sufficiently known to the person skilled in the art from the prior art. Therefore, for the sake of simplicity and conciseness, a more detailed description of this is omitted here. The invention can also be applied to a variety of mains-operated handheld power tools that have a slide switch, preferably operated by means of the thumb, for switching an associated drive motor on and off, such as angle grinders, polishing machines, milling machines, rod saws, etc.

[0044] Fig. Figure 2 illustrates a protective device 100 according to a first embodiment, with which the protective device 32 of Fig. 1, and which has an electrical switch 102 and a relay 104. The electrical switch 102 is mounted on the tool housing (12 of Fig. 1) and the slide switch 24 associated therewith of Fig. 1 can be operated by a user. The slide switch 24 is mounted on the sliding member 106 in a spring-loaded manner and is in an “operating position” when the drive motor (28) is switched on. Fig. 1) can be mechanically locked to the tool housing.

[0045] Mechanical actuation of the electrical switch 102 is effected via a plunger 108, which is mechanically fixed to the sliding member 106. The power supply of the protective device 100 and the drive motor of the hand-held power tool is effected via the power cable 26 from Fig. 1. The necessary electrical connection between the electrical switch 102, the relay 104 and the power cable 26 is made with several, preferably flexible electrical cables 110, in particular with stranded wires or the like.

[0046] Fig. 3 illustrates an electrical structure of the protective device 100 of Fig. 2 with the electrical switch 102 and the relay 104 controlled by it, whereby the drive motor 28 is Fig. 1 is in the off state. The electrical switch 102 comprises a normally open contact and a normally closed contact 112, 114, which are connected by means of the plunger 108 Fig. 2 are mechanically actuated, while relay 104 only has a (relay) working contact 116, which can be electromagnetically activated by means of a coil 118. The power supply is provided via the power cable 26, for example, from a (low-voltage) supply network with a voltage of 230 V at a frequency of approximately 50 Hz.

[0047] Starting from the switching state shown, in order to switch on the drive motor 28, the working contact 112 of the electrical switch 102 is moved by correspondingly moving the slide switch 24 from Fig. 2 is closed into an "operating position" at least briefly, whereby the working contact 116 of the relay 104 closes and this is placed in a self-holding mode, so that the drive motor 28 remains permanently switched on via the closed working contact 116 regardless of the switching state of the working contact 112. Due to the self-holding of the relay 104, the slide switch 24 can be Fig. 2 while working with the hand tool 10 of Fig. 1 must be released by the user. Due to the preferably additional mechanical locking of the slide switch in its “operating position” with the tool housing 12 of Fig. 1 provides haptic feedback when the slide switch has reached its "operating position," and its position is also clearly defined by the latching mechanism. If necessary, the additional mechanical latching mechanism of the slide switch 24 can be used due to the plunger 108 automatically engaging when fully pressed in. Fig. 2 are omitted.

[0048] If an interruption in the power supply occurs, the self-holding of relay 104 is canceled, since the coil 118 is de-energized and the make contact 116 thus opens. An uncontrolled restart of the drive motor 28 is also excluded upon a return of the power supply 120, since due to the then opened make contact 112 of the electrical switch 102, the relay 104 cannot pick up and go into self-holding and the drive motor 28 remains switched off. During a regular switch-off process, the slide switch 24 is Fig. 2 is moved by the user from the locked "operating position" back into a "switched-off position", whereby the break contact 114 of the electrical switch 102 is briefly opened and the self-holding of the relay 104 is canceled and the drive motor 28 is de-energized.

[0049] The reference numbers 200, 202, 212, 214 in Fig. 3 refer to a second embodiment of an electrical switch 202, which is used in the context of the second embodiment of the protective device 200 according to the Fig. 5A to Fig. 5D is explained below. The electrical functionality of switches 102, 202 is identical, whereas their mechanical design differs.

[0050] Fig. 4A shows the electrical switch 102 of Fig. 2 and Fig. 3 with the electrical make and break contacts 112, 114, which are actuated by means of the plunger 108, wherein a lever 130, which is articulated on the plunger 108, is guided in an approximately rectangular guide track 132, preferably in a circular manner, and the plunger 108 is mechanically prestressed by a compression spring 134 in the axial direction, i.e., in a direction away from the contacts 112, 114 of the switch 102. A cross-sectional geometry of the guide track 132 itself is preferably at least approximately rectangular.

[0051] The Fig. 4B to Fig. 4E - to which reference will also be made in the further course of the description - show four different electrical switching states of the electrical switch 102 of Fig. 4A to explain its electrical and mechanical operation. A region of the circumferential, self-contained guide track 132 facing the plunger 108 is designed as a diagonally extending track section 136. In the Fig. 4B - which is identical to the position shown in Fig. 4A - the plunger 108 is in a fully disengaged rest position, with the make contact 112 open and the break contact 114 closed and the drive motor 28 of the hand-held power tool 10 Fig. 1 is switched off. By moving or pushing the plunger 108 in the direction of an arrow 138, as shown in Fig. 4C, the working contact 112 is closed at least briefly, so that the relay 104 of Fig. 2 and Fig. 3 is set to self-locking and the drive motor is permanently switched on. Subsequently, the plunger 108 reaches the Fig. 4D a fully depressed position and remains in this position, with the make contact 112 open and the break contact 114 still closed.

[0052] By actuating the plunger 108 again or by slightly pushing it past its dead center in the direction of the contacts 112, 114, the plunger 108 moves as shown in Fig. 4E due to the force effect of the compression spring 134 in the direction of an arrow 140 out of the electrical switch 102, whereby the break contact 114 is opened at least briefly by means of the lever 130, the self-holding of the relay is canceled and the drive motor 28 is Fig. 1 is switched off. After passing through the Fig. 4E shown position of the plunger 108, the lever 130 is returned within the guide track 132 to its initial position according to Fig. 4B, in which the plunger 108 is in the fully disengaged rest position. A movement of the lever 130 in the opposite direction from the position shown in Fig. 4B shown position to the position of Fig. 4E is excluded due to a slight vertical offset 142 within the slide track 132.

[0053] It should be noted that the positively guided lever 130 rotates circularly within the guide track 132 due to the force of the compression spring 134 during the compression and extension of the plunger 108, and therefore takes a different path or branch through the guide track 132 during compression and extension. As a result, the normally open contact 112 and the normally closed contact 114 of the switch 102 are always actuated one after the other and only briefly.

[0054] Fig. 5A shows a protective device 200 according to a second embodiment, with which the protective device 32 of Fig. 1. This comprises an electrical switch 202 and the relay 104 of Fig. 2 and Fig. 3. The electrical switch 202 is preferably mounted on the tool housing 12 by means of a longitudinally displaceable Fig. 1 accommodated sliding member 204 can be actuated by a user, wherein on the sliding member 204 the slide switch 24 of Fig. 1 is mounted spring-loaded and tiltable. The slide switch 24 is in the “operating position” when the drive motor 28 is switched on. Fig. 1 can be mechanically locked to the tool housing 12.

[0055] The mechanical actuation of the electrical switch 202 is effected via an axially displaceable plunger 206, which has an actuating hook 208 at its end. The plunger 206 is connected to the sliding member 204 in a sliding-lock manner and is mechanically preloaded by a compression spring 210 such that the plunger 206 can be pressed into the electrical switch 202 against the force of the compression spring 210.

[0056] The electrical switch 202 preferably has a normally open contact 212 and a normally closed contact 214, between which the actuating hook 208 of the plunger 206 is arranged, whereby an alternating actuation of the two contacts 212, 212 is always ensured by moving the actuating hook 208 of the plunger 206. In the position of the electrical switch 202 shown, the normally open contact 212 is open and the normally closed contact 214 is closed. The electrical function and wiring of the protective device 200 correspond to the electrical wiring of the protective device 100 of Fig. 3, so that at this point a more detailed description is omitted and the explanations of the circuit diagram of Fig. 3 can be referred to.

[0057] The Fig. 5B to Fig. 5E - to which reference will also be made in the further course of the description - each show side views of the protective device 200 of Fig. 5A with four different electrical switching states of the electrical switch 202 of Fig. 5A, to explain its electrical and mechanical operation. In the Fig. In the position of the plunger 206 illustrated in Figure 5B, due to the force of the compression spring 210, the plunger is in its position in which it is pulled out of the electrical switch 202 to the maximum, so that the working contact 212 and the rest contact 214 are equally open, the self-holding of the relay 104 of Fig. 5A is lifted, the drive motor 28 of Fig. 1 is switched off and the slide switch 24 is in its "off position". The break contact 214 is pulled into its open switching state by means of the actuating hook 208 of the plunger 206 and is held in this state by the force of the compression spring 210. Accordingly, the slide switch 24 and the slide member 204 have their maximum retracted position relative to the tool housing 12 of Fig. 5A and a locking lug 216 formed on the underside of the slide switch 24 is disengaged from a recess 218 of the tool housing 12.

[0058] By moving the slide switch 24 from its position in Fig. 5B in the direction of an arrow 220 - ie in the direction of the "operating position" of the slide switch 24 - by a user is as shown in Fig. 5C, the normally closed contact 214 of the electrical switch 202 is initially closed and in this way the self-holding of the relay 104 of Fig. 5A prepared.

[0059] The working contact 212, however, remains in the open state while maintaining its contact distance 222.

[0060] By further pushing the slide switch 24 in the direction of the arrow 220, the Fig. 5D - also the working contact 212, the relay 104 of Fig. 5A goes into self-holding mode and the drive motor 28 of Fig. 1 is switched on. During this process, the slide switch 24 overruns as shown in Fig. 5D, however, briefly moves its mechanically locked "operating position" by a length 224 until a maximum "end position" of the slide switch 24 is reached. The overrun length 224 corresponds to the distance between the locking lug 216 and the recess 218 of the tool housing 12 in the position of the slide switch 24 according to Fig. 5D and is preferably at least 1 mm. Furthermore, the length 224 approximately corresponds to the contact spacing 222 of the non-actuated working contact 212 of the electrical switch 202, so that after the slide switch 24 is released by the user, the slide switch 24 automatically moves from the "end position" into the "operating position" according to FIG. 1 due to a force effect of the compression spring 210 directed opposite to an arrow 220. Fig. 5E is retracted, whereby the locking lug 216 engages the recess 218 of the tool housing 12, so that the slide switch 24 is mechanically locked to the tool housing 12 in the then reached "operating position." Since the length 224 approximately corresponds to the contact spacing 222, the normally open contact 212 is opened again in the engaged "operating position," whereby the drive motor remains switched on due to the self-locking relay. The normally closed contact 214 of the electrical switch 202 remains closed.

[0061] For user-side switching off of the drive motor 28 from Fig. 1, the slide switch 24 is moved from its “operating position” according to. Fig. 5E from the tool housing 12. As a result, the plunger 206 with its actuating hook 208 moves back due to the force of the compression spring 210 until the Fig. 5B is reached, in which the normally open contact 212 and the normally closed contact 214 are open. This releases the self-holding of the relay 104 from Fig. 5A is cancelled and the drive motor is permanently switched off. However, if an unexpected power interruption occurs in the "operating position" of the slide switch 24 according to the Fig. 5E, the relay's self-locking function is immediately canceled, and the drive motor is immediately switched off by the relay's normally open contact. After the power supply is restored, an uncontrolled restart of the drive motor is prevented because the normally open contact 212 of the electrical switch 202 remains in the engaged "operating position" of the slide switch 24, as shown in Fig. 5E is open. In order to switch the drive motor back on in a controlled manner after a power failure, the user must first move the slide switch 24 from its engaged “operating position” back to its “off position” as shown. Fig. 5B and then switches the drive motor on according to the sequence of switching positions of the electrical switch 202 according to the Fig. 5B to Fig. 5E switches on again.

[0062] Fig. 6 and Fig. 7 - to which reference will also be made in the further course of the description - show two circuit diagrams of a third and fourth embodiment of a protective device. In contrast to the two embodiments described above, in the protective device of Fig. 6 and Fig. 7 the relay also performs the function of the otherwise necessary electrical switch.

[0063] As in Fig. 6, a relay 300 is provided, the coil 302 of which is connected in parallel to the drive motor 28 of Fig. 1. Thus, the drive motor 28 can be connected to a power supply (e.g. the power supply 120 of Fig. 3) and switched on. Coil 302 and make contact 304 are illustratively integrated into a housing 306 of relay 300. As a result of an exemplary parallel connection of coil 302 and drive motor 28, relay 300 is latched when drive motor 28 is sufficiently energized, so that drive motor 28 runs continuously. If a power interruption occurs, the latching of relay 300 is canceled, make contact 304 opens, and drive motor 28 can only be switched on again in a controlled manner by mechanically forcing make contact 304.

[0064] Fig. 7 shows in contrast to Fig. 6 a relay 400 with a coil 402, by means of which a first and a second working contact 404, 406 can be actuated, wherein activation of the coil 402 does not take place by means of the voltage which, when the drive motor 28 is switched on, Fig. 1 across it, but through the second working contact 406 and thus independent of a drive motor current that flows exclusively through the first working contact 404. As a result, a coil current of the relay 400 is thereby independent of the drive motor current that flows through the switched-on drive motor 28. Both working contacts 404, 406 are mechanically synchronously actuated, i.e. closed, at least when the coil 402 is energized. By, for example, mechanically forced closing of the working contact 406 by a user, the relay 400 goes into self-holding, whereby the working contact 404 is closed and the drive motor 28 is switched on. In the further course of the description, however, it is assumed that the third and fourth embodiments of the protective device have the electrical connection of Fig. 6 is the basis.

[0065] Fig. Fig. 8A illustrates a protective device 500 according to the third embodiment, which has a relay 502 which is mechanically connected to a longitudinally displaceable on the tool housing 12 of the hand-held power tool 10 of Fig. 1 is coupled to the sliding member 504. As with the sliding member 204 of Fig. 5B, the slide switch 24 is resiliently tilted, the underside of which can be engaged in the recess 218 of the tool housing 12. The sliding member 504 is mechanically preloaded by means of a compression spring 506 supported on the tool housing 12.

[0066] Relay 502 has a coil 508 and a normally open contact 510, which has a fixed contact arm 512 and a flexible contact arm 514. An angular armature 516 of relay 502 has a first and a second leg 518, 520 and is preferably mounted in the region of armature 516 so as to be at least slightly tiltable.

[0067] A preferably play-related mechanical coupling between the sliding member 504 and the relay 502 is achieved by a contact slide 524 which is accommodated in a longitudinally displaceable manner within a housing 522 of the relay 502. This contact slide 524 has, on an upper side facing the sliding member 504, a cuboid-shaped projection 526 which is positioned between a first and a second transverse rib 528, 530 which are spaced apart from one another and are formed on the underside of the sliding member 504. An axial play 532 remains between the projection 526 and the transverse ribs 528, 530 of the contact slide 524. An internal distance between the two transverse ribs 528, 530 corresponds at least approximately to the axial play 532 plus a width of the projection 526. On an underside of the contact slide 524 facing the coil 508, a fork 534 is formed for articulately receiving one end of the elastic contact arm 514 of the working contact 510.

[0068] A corresponding electrical connection of the protective device 500 is preferably carried out in a similar way to Fig. 6. Alternatively, a connection according to Fig. 7 can be used, in which the relay has an additional working contact for electrically decoupling the (relay) coil current from the drive motor current.

[0069] The Fig. 8B to Fig. 8F - to which reference will also be made in the further course of the description - each show side views of the third embodiment of the protective device of Fig. 8A with four different electrical and mechanical states of a corresponding relay to explain the electrical and mechanical functioning. In a Fig. 8B, the slide switch 24 is in its “off position”, in which the locking lug 216 is disengaged from the recess 218 of the tool housing 12 and in which the relay 502 of the protective device 500 is de-energized and the working contact 510 is open, so that the drive motor 28 of Fig. 1 is switched off and the self-holding of relay 502 is canceled. Due to the force of compression spring 506, the first transverse rib 528 rests against projection 526 of contact slide 524, which in turn strikes the inside of the housing 522 of relay 502, which acts as a travel limiter.

[0070] By moving the slide switch 24 in the direction of an arrow 536 and against the force of the compression spring 506, the slide switch 24 reaches a Fig. 8C. Here, the flexible contact arm 514 is mechanically forced by the contact slide 524 to bend towards the fixed contact arm 512 until the working contact 510 of the relay 502 closes and the drive motor 28 is Fig. 1 and the coil 508 are energized, whereby the relay 502 begins to enter the self-holding state. In this "end position" of the slide switch 24, the locking lug 216 has overrun the recess 218 in the tool housing 12 by a small length 538, which is preferably at least 1 mm. The projection 526 of the contact slide 524 rests against the second (rear) transverse rib 530 of the sliding member 504. As a result, the coil 508 can be actuated as in Fig. 8D, the first leg 518 of the armature 516 is pulled, causing the second leg 520 of the angular armature 516 to engage the elastic contact arm 514, and the relay 502 to be in the pulled-in state. This simultaneously holds the elastic contact arm 514 in its reached position, so that the relay 502 is self-locking. The horizontal position of the slide switch 24, the slide member 504, and the contact slide 524 remain unchanged.

[0071] If a corresponding user now moves the slide switch 24 from the end position of Fig. 8D, it moves together with the sliding member 504 due to the force of the compression spring 506 back towards the relay 502, so that the locking lug 216 - as can be seen from Fig. 8E - engages in the recess 218 of the tool housing 12 and, in addition to the electromechanical self-locking of the relay 502, a mechanical position securing of the slide switch 24 and the sliding member 504 is provided in a then reached, engaged "operating position" of the slide switch 24.

[0072] The electrical switching state of the relay 502 remains unchanged due to its self-holding, so that the working contact 510 of the relay 502 remains closed and the drive motor 28 is Fig. 1 remains permanently switched on. In this position, there is a horizontal distance 542 between the second (rear) rib 530 of the sliding member 504 and the projection 526 of the contact slide 524, which approximately corresponds to the length 538 (cf. Fig. 8D). Due to the distance 542, in the engaged state of the slide switch 24, the absolutely necessary axial play is created between the sliding member 504 and the contact slide 524, which enables the opening of the working contact 510 when the coil 508 of the relay 502 is de-energized and, as a result, the armature 516 or the first leg 518 drops off the coil 508.

[0073] If an unexpected interruption in the power supply occurs, the coil 508 of the relay 502 is de-energized, causing the first leg 518 of the armature 516 - as shown in Fig. 8F - falls off the coil 508 and the second leg 520 of the angular armature 516 is forced back into its rest position by the spring action of the elastic contact arm 514, in which it rests against the coil 508. This results in the make contact 510 opening and the self-holding of the relay 502 being immediately canceled and thus the drive motor 28 from Fig. 1 is switched off. In the event of a return of the power supply, the drive motor will not restart, as the working contact 510 of the relay 502 remains in the open position. To switch the drive motor on again, the user must first disengage the slide switch 24 from the recess 218 of the tool housing 12, whereby the slide switch 24 immediately returns to its Fig. 8B. The drive motor is then switched on again by actuating the slide switch 24 again, as in Fig. 8B to Fig. 8E, until the “operating position” of the slide switch 24, which is mechanically locked to the tool housing 12, is reached again and the drive motor of the hand-held power tool 10 is Fig. 1 is switched on and the self-holding of relay 502 is activated.

[0074] Fig. Figure 9A shows a protection device 600 according to the fourth embodiment, which has a relay 602 which, like the relay 502 of Fig. 8A is mechanically coupled to a sliding member 604 mounted on the tool housing 12 of the hand-held power tool in a longitudinally displaceable manner. As with the sliding member 204 of Fig. 5B, the slide switch 24 is resiliently tilted, on the underside of which the locking lug 216 is formed, which can be locked into the recess 218 in the tool housing 12 to provide a user with haptic, intuitive feedback about reaching the "operating position" of the slide switch 24 and, moreover, to mechanically fix its position in this position. The slide member 604 is mechanically preloaded in the axial direction by means of a compression spring 606 supported on the tool housing 12 and connected to the slide member 604.

[0075] Relay 602 has a coil 608 and a normally open contact 610. The normally open contact 610 is configured with an angled, preferably stationary contact arm 612 and a preferably movable contact arm 614. The stationary contact arm 612 is attached internally to a housing 616 of relay 602, while the movable contact arm 612 is attached at its end to an illustratively plate-shaped armature 618, which is pivotably connected internally to the housing 616 of relay 602, for example, by means of a film joint. The armature 618 is magnetically attracted to the coil 608 when energized, thereby closing the normally open contact 610 of relay 602. Furthermore, a capacitor 620 for radio interference suppression is integrated into the housing 616.An external geometry of the housing 616 is preferably identical to the external dimensions of electrical switches without restart protection commonly used in mains-operated hand-held power tools, so that replacement is possible without modifications to series production.

[0076] A mechanically forced actuation of the armature 618 is preferably achieved by means of a substantially cylindrical plunger 622, which has a bearing section 624 with, for example, a fork-shaped receptacle 626 for articulating the movable contact arm 614 or the armature 618. Adjoining the bearing section 624 is a coupling section 628, which, for example, has a reduced cross-section compared to the bearing section 624 and which serves for mechanical coupling to an angled leg 630 of the sliding member 604. Through its bearing section 624, the plunger 622 is axially displaceably received in the housing 616 of the relay 602. An optional sealing member 632 in the form of an elastic bellows made of an elastomer or the like is attached to the housing 616 as well as to the bearing portion 624 of the plunger 622 to prevent foreign particles from entering the housing 616 of the relay 602.For the functionally necessary, play-related axial coupling between the plunger 622 and the sliding member 604, a bore 634 is provided in the leg 630 for the passage of the coupling section 628. To prevent the plunger 622 from sliding off the leg 630 of the sliding member 604, a disc-shaped or mushroom-shaped stop 636 is provided at the end of the coupling section 628 of the plunger 622, the outer diameter of which is at least slightly larger than an inner diameter of the bore 634. A further end stop for the leg 630 is formed by a shoulder 638 between the bearing section 624 and the coupling section 628 of the plunger 622. Between the shoulder 638 and the stop 636 formed at a distance therefrom on the plunger 622, an axial play 640 thus results, which has the result that the leg 630 of the sliding member 604 and the plunger 622 can be displaced relative to one another by the axial play 640.

[0077] The Fig. 9B to Fig. 9F - to which reference will also be made in the further course of the description - each show side views of the fourth embodiment of the protective device of Fig. 9A with four different electrical and mechanical states of a corresponding relay to explain the electrical and mechanical functioning. In Fig. 9B, the locking lug 216 of the slide switch 24 is disengaged from the recess 218 in the tool housing 12, and the slide switch 24, together with the sliding member 604, is moved into a "switch-off position" shown due to the force of the compression spring 606, in which the plunger 622 simultaneously assumes a position in which it protrudes or is pulled out of the housing 616 of the relay 602 to its maximum extent. The receptacle 626 of the plunger 622 for the movable contact arm 614 abuts the inside of the housing 616 of the relay 602, thereby forming a necessary axial travel limit for the plunger 622.

[0078] In the “off position” the working contact 610 of the relay 602 is open, the drive motor 28 of the hand tool 10 is Fig. 1 is switched off and the self-holding of relay 602 is cancelled (see in particular Fig. 6). As in Fig. 9C, to switch on the drive motor, the slide switch 24 is pushed forward by the user in the direction of an arrow 642 against the force of the compression spring 606 until the slide switch 24 and the sliding member 604 have a Fig. 9C. In this "end position," the locking lug 216 of the slide switch 24 has overrun the recess 218 in the tool housing 12 by a small length 644, wherein this length 644 is preferably at least 1 mm. Due to this circumstance, the slide switch 24 does not yet lock into the housing 12 of the handheld power tool in the "end position" shown.

[0079] The plunger 622 is carried along by means of its shoulder 638 during this movement by the leg 630 of the sliding member 604, which moves in the direction of the arrow 642. As a result, the movable contact arm 614 is brought into contact with the stationary contact arm 612 by the receptacle 626 of the plunger 622 and, as a result, the working contact 610 of the relay 602 is forced closed. This in turn results in the drive motor 28 being driven by Fig. 1 is switched on and the coil 608 of the relay 602 is energized, whereby the armature 618 is magnetically attracted to the coil 608 and the relay 602 goes into self-holding mode. In the position of the slide switch 24 of Fig. 9C, the compression spring 606 has preferably reached its most compressed state.

[0080] As in Fig. As shown in Figure 9D, the slide switch 24 has Fig. 9C, as a result of the release of the slide switch 24 by the user and the return force of the compression spring 606, a mechanically locked “operating position” is assumed in which the drive motor 28 of Fig. 1 remains permanently switched on regardless of continued actuation of the slide switch 24 by the user due to the self-holding of the relay 602. During the transition from the “end position” to the “operating position”, the slide switch 24 slides back by the length 644 into its mechanically latched position. In the mechanically latched state, the locking lug 216 of the slide switch 24 is at least partially received in the recess 218 of the tool housing 12 in a form-fitting manner. The relay 602 remains in the energized state when the coil 608 is energized, so that the make contact 610 remains permanently closed when the armature 618 is energized. Starting from its axial position according to Fig. 9C, the leg 630 of the sliding member 604 has lifted off the shoulder 638 of the plunger 622 by a length 646. The length 646 corresponds approximately to the length 644 (cf. Fig. 9C).

[0081] To switch the drive motor 28 of the hand tool 10 from Fig. 1 off again, it is necessary for the user to move the slide switch 24 starting from the position shown in Fig. 9D shown, mechanically locked "operating position" in the direction of an arrow 648 with the support of the force exerted by the compression spring 606 until an "off position" of the slide switch 24 according to. Fig. 9E is reached and the locking lug 216 is again released from the recess 218 of the tool housing 12.

[0082] With the support of the force of the compression spring 606, during this user-initiated, mechanical switching-off process, the plunger 622 is pulled out of the housing 616 of the relay 602 by the leg 630 of the sliding member 604 until the Fig. 9E shown "off position" of the slide switch 24 is reached again. As a result, the movable contact arm 614 is mechanically lifted from the fixed contact arm 612 of the relay 602 against the magnetic attraction force of the coil 608 still acting on the armature 618, whereby the make contact 610 of the relay 602 opens and the coil 608 is de-energized. This suspends the self-holding of the relay 602 and the drive motor 28 from Fig. 1 is switched off. Between the leg 630 of the sliding member 604 and the shoulder 638 of the plunger 622, the axial play 640 exists in the shown position of the slide switch 24 (see also Fig. 9A). The capacitor 620 serves only to suppress radio interference of the working contact 610 when the movable contact 614 lifts off the fixed contact 612.

[0083] Starting from the mechanically locked “operating position” of the slide switch 24 according to Fig. 9D, however, unexpectedly a power interruption occurs, the self-holding of the relay 602 breaks down immediately due to the then occurring currentlessness of the coil 608 of the relay 602 and the working contact 610 of the relay 602 takes its in Fig. 9F. During this process, the movable contact 614, which springs back under its own power or automatically, takes the plunger 622 with the aid of the fork-shaped receptacle 626 in the direction of an arrow 650 - independently of the slide switch 24, which is still mechanically locked to the housing 12, and the slide member 604 connected thereto. This is possible because the plunger 622, starting from its position according to Fig. 9D, when the coil 608 is de-energized, can be displaced back independently of the sliding member 604 by the length 646 within the bore 634 of the leg 630. The length 646 is greater than or equal to a contact distance 652 between the fixed contact arm 612 and the movable contact arm 614 in the open state of the normally open contact 610 in order to achieve reliable electrical separation.

[0084] In case of a return of the power supply, the drive motor 28 can be Fig. 1 cannot start up again because the normally open contact 610 of the relay 602 remains open, so that neither the drive motor nor the coil 608 of the relay 602 can be energized again.

[0085] To move the drive motor 28 from Fig. 1 starting from the Fig. 9F, it is first necessary for the user to mechanically unlock the slide switch 24 and move it to the position shown in Fig. 9A and Fig. 9B shown "off position" in relation to the tool housing 12. The drive motor can then be switched on again by moving the slide switch 24 starting from the "off position" as shown in FIG. Fig. 9A and Fig. 9B until the “operating position” is reached in accordance with. Fig. 9D can be started again without compromising work safety.

Claims

[1] Mains-operated hand-held power tool (10) with a tool housing (12) in which an electric drive motor (28) for driving an associated insert tool (40) is arranged, wherein a slide switch (24) coupled to a slide member (30, 106, 204, 504, 604) for switching the drive motor (28) on and off is arranged at least longitudinally displaceably on the tool housing (12), characterized bythat a protective device (100, 200, 500, 600) with an electromechanical relay (104, 300, 400, 502, 602) is provided, which is designed to prevent, by means of the electromechanical relay (104, 300, 400, 502, 602), an uncontrolled restart of the drive motor (28) after an interruption of a corresponding power supply to the drive motor (28) by canceling a self-holding of the relay (104, 300, 400, 502, 602), wherein a working contact of the relay (104, 300, 400, 502, 602) opens and the working contact of the electrical switch is open orthe break contact of the electrical switch is closed, wherein the sliding switch (24) is tiltably received on the sliding member (30, 106, 204, 504, 604) and can be locked to the tool housing (12) in an operating position when the drive motor (28) is switched on, wherein the protective device (100, 200) has an electrical switch (102, 202) with a make contact (112, 212) and a break contact (114, 214), wherein the make contact (112) and the break contact (114) can be actuated by means of a lever (130) tiltably received on the plunger (108), wherein the lever is guided circumferentially in a guide track (132) with an approximately quadrangular outline and the guide track (132) has at least one diagonally running track section (136). [2] Hand tool according to claim 1, characterized bythat the electrical switch (102) has a plunger (108) prestressed by means of a compression spring (134) which is axially displaceable by means of the sliding member (106) against a spring force applied by the compression spring (134). [3] Hand tool according to claim 1, characterized by that the working contact (112) can be closed at least briefly by axial actuation of the plunger (108) from a rest position in order to put the relay (104) into self-locking and to switch on the drive motor (28), wherein the plunger (108) remains in a depressed position. [4] Hand tool according to claim 3, characterized by that the rest contact (114) can be opened by a further axial actuation of the plunger (108) to switch off the drive motor (28) in order to cancel the self-holding of the relay (104), wherein the plunger (108) is urged back into its rest position by means of the spring force of the compression spring (134). [5] Hand tool according to claim 1, characterized by that the electrical switch (202) has a plunger (206) prestressed by means of a compression spring (210) with an actuating hook (208), wherein the plunger (206) is axially displaceable by means of the sliding member (204) against a spring force applied by the compression spring (210). [6] Hand tool according to claim 5, characterized by that the actuating hook (208) is arranged in the area between the working contact (212) and the rest contact (214) of the electrical switch (202) in order to enable alternating actuation of the working contact (212) and the rest contact (214). [7] Hand tool according to claim 5 or 6, characterized by that the working contact (212) is open and the rest contact (214) is closed in a latched operating state of the slide switch (24), the drive motor (28) being switched on by the self-holding of the relay (104). [8] Hand tool according to claim 1, characterized by that the sliding member (504) is pre-tensioned by means of a compression spring (506) supported on the tool housing (12). [9] Hand tool according to claim 8, characterized by that by means of the sliding member (504) a contact slide (524) can be displaced with play within the relay (502) parallel to the sliding member (504) in order to energize a coil (508) of the relay (502) by forced mechanical closing of a working contact (510) of the relay (502). [10] Hand tool according to claim 9, characterized byin that the relay (502) has an angled armature (516) which is tiltably mounted within the relay (502) and has a first and a second leg (518, 520) for self-holding, wherein by energizing the coil (508) the first leg (518) is magnetically attracted to it in such a way that when the coil (508) is energized the working contact (510) of the relay (502) can be held mechanically in the closed switching state by means of the second leg (520). [11] Hand tool according to claim 8, characterized by that the relay (602) has a coil (608) and a plate-shaped armature (618) which can be magnetically attracted by the coil (608), and by means of the armature (618) a working contact (610) of the relay (602) can be actuated. [12] Hand tool according to claim 11, characterized bythat by means of the sliding member (604) a plunger (622) projecting from the relay (602) for actuating the armature (618) can be displaced with play parallel to the sliding member (604). [13] Hand tool according to claim 12, characterized by that the plunger (622) is sealed against a housing (616) of the relay (602) by means of a sealing member (632). [14] Hand tool according to claim 12 or 13, characterized by that by mechanically forced actuation of the plunger (622) by means of the sliding member (604), a working contact (610) of the relay (602) can be closed and the coil (608) of the relay (602) can be energized in order to switch on the drive motor (28) and to put the relay (602) into self-holding. [15] Hand tool according to one of claims 11 to 14, characterized bythat the relay (602) is identical in terms of its external geometry to a standard electrical switch for switching the drive motor (28) of the hand-held power tool (10) on and off.

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