Switch for electric appliance and electric appliance including such switch

Abstract

The invention relates to an electrical switch (30) for an electric appliance (2), in particular an electric tool, the electrical switch having at least two switch contacts (34, 36) movable in conjunction, the switch contacts (34, 36) being movable between an off position (38), in which the switch contacts (34, 36) are not electrically connected to a mating contact (42) of the switch (30), and an on position (40), in which the switch contacts (34, 36) are electrically connected to the mating contact (42). The object of the invention is to maintain the contact resistance of the switch (30) at a substantially constant value over the entire service life. According to the invention, this object is achieved in that the switch contacts (34, 36) and / or the mating contacts (42) are arranged and / or designed so that, when the switch (30) is switched between an off position (38) and an on position (40), the switch contacts (34, 36) successively come into electrical contact with the mating contact (42) or successively break electrical contact.

Description

Technical Field

[0001] The present invention relates to an electrical switch for an electric appliance, in particular for an electric tool, the electrical switch having at least two switch contacts which can be moved in conjunction with each other, the switch contacts being movable between an off position and an on position, in which the switch contacts are not electrically connected to a mating contact of the switch, and in which the switch contacts are electrically connected to the mating contact.

[0002] Furthermore, the invention relates to an electric appliance, in particular an electric tool, having such a switch. Background Art

[0003] The switch is preferably designed as a sliding switch, wherein the switch has a sliding member having at least two switch contacts. The switch may have a regulator for regulating the current supply to the electrical load, in particular for regulating the rotational speed of the electric motor of the electrical appliance. In particular, the switch is preferably designed as a signal switch, which does not directly switch the supply current of the electric motor, but indirectly via the control electronics of the electrical appliance. The switch then only switches a lower signal current for controlling the control electronics, which in turn switches the relatively higher supply current of the electric motor depending on the signal current. The control electronics are used, for example, to control a brushless (collectorless) motor (so-called BLAC or BLDC motor).

[0004] When the switch switches an electrical load indirectly using control electronics, the signal current is in the range from about 0.1 mA to 20 mA. However, the control electronics may have a capacitor, in particular an electrolytic capacitor. When a plurality of consecutive switching cycles are switched on for the first time, the capacitor must first be charged. Depending on the size of the capacitor and how fast the load should respond after the switch is switched on, the charging current can reach values ​​of more than 1.0 A. However, high surge currents can cause contact corrosion (also called material migration) on the contact surface of the mating contact, in particular if the mating contact is formed as a relatively thin conductive track (typically with a layer thickness of between 35 μm and 70 μm) on the printed circuit board. Contact corrosion can lead to material transfer on the contact surface of the mating contact and extend the contact stroke. In addition, for known switches in which two switch contacts are switched simultaneously, the two switch contacts are equally contaminated, resulting in occasional contact uncertainty and higher contact resistance. All in all, the extension of the contact stroke and the stability of the contact resistance over the entire service life of the switch are problems with known switches.

[0005] Such a switch is known, for example, from EP 1 873 800 A1. In order to ensure safe contact between a slider with a switch contact and a mating contact designed as a conductive track on a printed circuit board, the known switch has several, in particular two, switch contacts (so-called double slider contacts). When establishing or interrupting the electrical contact between the slider and the conductive track in the switching point region, switching sparks, arcs and harmful electrical corrosion (e.g. contact corrosion) are generated, in particular when the current to be switched is relatively large (e.g. 1 A and higher). In the known switch, the two switch contacts in the switching point make or break contact simultaneously, i.e., switching sparks, arcs and electrical corrosion occur equally at the two switch contacts or at the matching contact areas of the rising contour of the conductive track. Contact corrosion can lead to a longer contact stroke in an undesirable manner. In addition, contact corrosion can lead to a shortened service life or a reduced switching capacity (number of switching cycles on the load) and to an increased contact resistance of the switch. Summary of the invention

[0006] Based on the described prior art, the invention solves the problem of improving the service life and switching capacity of a switch having several switching contacts and keeping the electrical properties of the switch, in particular the contact resistance and the switching travel, as constant as possible over the entire service life of the switch.

[0007] In order to solve this problem, it is recommended to start from a switch of the type mentioned above, arrange and / or design the switch contacts and / or mating contacts so that when the switch is switched between the off position and the on position at the switching point, the switch contacts successively enter into electrical contact with the mating contacts or successively break electrical contact.

[0008] The switch contacts of the switch are preferably part of the sliding member and are interconnected in an electrically conductive manner. Compared with the prior art, in which all the switch contacts of the switch are in electrical contact with the mating contact at the same time, in the present invention, the process is sequential or progressive. In this context, "successively" means that at the switching point, an electrical connection is first established between the first switch contact and the mating contact, thereby closing the switch. Only after the electrical connection is made and the switch is closed, the other switch contact is in contact with the mating contact. Therefore, sparks, arcs and electrical erosion can only occur between the matching contact areas of the first switch contact and the mating contact. When the other switch contact is in contact with the matching contact area of ​​the mating contact, the switch is already closed, that is, no sparks, arcs or discharges are generated at the matching contact areas of the other switch contact or the mating contact. Therefore, the additional switch contact can ensure that the closed switch has a constant contact resistance throughout its service life. Therefore, the switch contacts and / or the mating contacts of the switch are arranged and / or designed such that, during the expected service life of the switch, electrical corrosion occurs only at the mating contact regions of the first switch contact and the mating contact, and does not occur at any other switch contact. In this way, a long-term reliable function of the switch, in particular a constant contact resistance, can be ensured despite the occurrence of electrical corrosion at the mating contact region of the mating contact or at one of the switch contacts.

[0009] The invention can be implemented in many ways. For example, the arrangement of the switch contacts relative to the direction of movement of the switch when closing or opening the switch, the design of the switch contacts or the design of the switch surfaces with which they come into contact with the matching contact areas of the mating contacts, or the arrangement and / or design of the contact areas (or contact surfaces) of the mating contacts can be varied and matched to one another. In order to implement continuous contact of the switch contacts, the switch contacts and the mating contacts or their contact surfaces at the switching point cooperate with one another.

[0010] The switch is particularly suitable for use in electric appliances, in particular electric tools. The switch is designed as a signal switch, which interacts with the control electronics of the electric appliance and switches a relatively low signal current (e.g., less than 100 mA, in particular 0.1-20.0 mA) for the control electronics, which in turn switches a significantly higher supply current (e.g., greater than 2 A, in particular 4-10 A) for an electric load of the electric appliance, in particular an electric motor of the electric tool. In electric appliances, the implementation of a high switching capacity of the switch is particularly important, as this can increase the service life of the entire electric appliance. In addition, it is very important to maintain a constant contact resistance throughout the service life of the electric appliance, as this is the only way to ensure that the electric appliance operates under constant conditions.

[0011] According to a particularly preferred further development of the invention, the switch has a regulator for adjusting the current supply to the electrical load of the electric tool, in particular for adjusting the rotational speed of the electric motor of the electric tool. When the switch is switched on, the controller is used to set the power supply. The same actuating element of the switch is used to first switch on the electric tool and then to change the rotational speed of the motor. The actuating element is designed, for example, as a slider or a knob.

[0012] According to a preferred embodiment of the invention, it is proposed that the switch contacts are spaced apart in a first plane. The first plane extends, for example, parallel to the extension plane of the flat mating contact and parallel to the direction of movement of the switch (when traveling between the disconnected position and the connected position). In order to close the switch, the switch contact is pushed onto the surface of the mating contact across the rising surface in the direction of movement. The switch contacts are also aligned in a second plane, which is transverse or inclined to the direction of movement of the switch and perpendicular to the first plane. The mating contact has a rising profile on its end facing the disconnected position, which extends in a third plane transverse or inclined to the direction of movement of the switch and perpendicular to the first plane. The second plane extends obliquely to the third plane.

[0013] Since according to this design, the switch contact has a different orientation than the rising profile of the mating contact when viewed in the direction of movement of the switch, the switch contact successively makes contact with the rising profile or the mating contact. It is conceivable that, for example, in a first configuration, the second plane extends transversely to the direction of movement of the switch, in which the switch contacts are aligned. The third plane will then be arranged obliquely to the direction of movement of the switch, in which the rising profile of the mating contact is located. In order to close the switch, the first switch contact first makes contact with the inclined first contact area of ​​the rising profile that protrudes further in the direction of the open position of the switch, before the other switch contacts make contact with the other contact areas of the rising profile.

[0014] In a second exemplary embodiment, the second plane in which the switch contacts are aligned extends obliquely to the direction of movement of the switch. The third plane in which the rising contour of the mating contact is positioned is then arranged transversely to the direction of movement of the switch. To close the switch, the first switch contact protruding further in the direction of the mating contact will first come into contact with the first contact area of ​​the transverse rising contour before the other switch contacts come into contact with the other contact areas of the rising contour.

[0015] According to another preferred embodiment of the present invention, it is proposed that the switch contacts are spaced apart in a first plane. The first plane extends, for example, parallel to the extension plane of the flat mating contact and parallel to the direction of movement of the switch (when traveling between the disconnected position and the connected position). In order to close the switch, the switch contact is pushed onto the surface of the mating contact across the rising surface in the direction of movement. The switch contact is also oriented in a second plane, which extends transversely or obliquely to the direction of movement of the switch and perpendicular to the first plane. The mating contact has a stepped rising profile relative to the second plane on its end facing the disconnected position. Preferably, one step in each stepped rising profile is assigned to each switch contact. In order to close the switch, the first switch contact first contacts the contact area in the region of the first step of the rising profile that further protrudes in the direction of the disconnected position of the switch before the other switch contacts contact the other contact areas in the region of the other rearwardly arranged steps of the rising profile.

[0016] The concept according to the invention can in principle be applied to switches, in particular sliding switches, with punched metal contacts, which are for example fixed or attached to a plastic substrate. However, particularly preferably, the switch is implemented on a printed circuit board (so-called PCB), wherein the mating contact is designed as a conductive track on the circuit board, preferably the conductive track has a thickness of the conductive material (for example copper) of less than 100 μm, in particular in the range from 35 μm to 70 μm. Even for such thin mating contacts, the invention can be used to ensure a constant contact resistance over the entire service life of the switch.

[0017] Furthermore, the switch is advantageously designed as a toggle switch and has mating contacts on both sides of the disconnect position in the direction of movement of the switch. One of the mating contacts forms a so-called normally open (NO) contact, while the other mating contact forms a so-called normally closed (NC) contact. That is, the switch has two switching points, an ON switching point on the normally open contact and an OFF switching point on the normally closed contact. Such switches are typically used in electrical appliances, in particular in electric tools. The normally closed contact can be used to generate a "safe disconnect" signal for the control electronics or to initiate braking of a controlled electric motor. Therefore, such a switch has two valid positions, namely, an effective ON position and an effective OFF position.

[0018] In the case where one or more mating contacts of the switch are formed as conductive tracks on an electrical printed circuit board (PCB), according to a preferred embodiment of the invention, it is proposed that the PCB has a notch or slot in the area corresponding to the disconnected position of the switch. In switches designed as toggle switches, the slot is formed in particular between two mating contacts. During the operation of the switch, particles, wear or corrosion (e.g., material transfer on the mating contacts due to electrical corrosion or mechanical material wear of the switch contacts) can form and deposit between the mating contacts, thereby impairing the function of the switch, for example because they cause leakage currents. These particles and microparticles can be removed from the area of ​​the disconnected position by means of notches or slits provided on the circuit board. In this way, the isolation properties of the switch can be improved and leakage currents can be prevented.

[0019] In order to improve the service life and switching performance of the switch, it is proposed to provide the rising contour of the mating contact with an additional coating of an electrically conductive material, in particular copper, silver, gold or the like, at least in the contact region where the first switching contact first makes electrical contact with the mating contact. Preferably, the additional coating has a thickness of more than 100 μm, in particular up to 1 mm, preferably about 0.2 mm. The additional coating can be designed, for example, as a welded or soldered contact plate. Such a switch is also suitable for long-term and frequent switching of higher currents and powers, which may occur, for example, when charging electrolytic capacitors for control electronics (about 1.0 A). In the case of a typical copper thickness of about 35 μm applied as a conductive track on a printed circuit board for the mating contact, contact corrosion causes a copper loss of the dimension X on the copper thickness of 35 μm each time the switch is switched in the direction of movement of the switch, resulting in an undesirable extension of the switch-on stroke. For an additional coating of about 0.2 mm thickness, the amount of copper available at the switching point increases by a factor of 5.7. That is, for conventional copper thicknesses, the switch-on travel is extended by only about 20% of the original value X. For a coating thickness of 0.2 mm, a reduction in the switch-on travel extension of about 80% can be achieved in this way. In this way, very tightly defined switch-on and switch-off travel tolerances (e.g., a tolerance of + / - 0.2 mm for a switch travel of 1.8 mm) can be maintained over a large number of switching cycles of 500,000 at currents of 0.1 to 20 mA, briefly up to more than 1 A.

[0020] For example, the switch according to the present invention can be designed as a rotary sliding switch, wherein the mating contact is shaped like an arc, and the switch contact can move around a rotation axis that passes through the center point of the mating contact shaped like an arc. Alternatively, the switch can also be designed as a linear sliding switch, wherein the mating contact is linear, and the switch contact can move on a sliding axis extending parallel to the longitudinal direction of the mating contact.

[0021] A switch designed as a slide switch or a slide of the switch preferably has exactly two switch contacts. This provides a good compromise between achieving a constant contact resistance on the one hand and high stability and robustness of the switch on the other hand. All in all, the result is a switch with significantly improved switching performance and service life.

[0022] The present invention also relates to an electric appliance, in particular an electric tool, which has a switch of the above type for connecting or disconnecting an electric device or an electric load, in particular an electric motor of the electric appliance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features and advantages of the present invention are explained in more detail below with reference to the accompanying drawings. In the drawings:

[0024] Figure 1 An exemplary embodiment of an electrical device in the form of a power tool is shown;

[0025] Figure 2 A schematic diagram of a switch known in the prior art is shown;

[0026] Figure 3 shows a schematic diagram of a first exemplary embodiment of a switch according to the present invention;

[0027] Figure 4 Shows Figure 3 An enlarged view of a cross section of a switch;

[0028] Figure 5 shows an enlarged schematic view of a cross section of a second exemplary embodiment of a switch according to the invention;

[0029] Figure 6 Shows Figure 5 The cross section of the switch;

[0030] Figure 7 shows an enlarged schematic view of a cross section of a third exemplary embodiment of a switch according to the invention;

[0031] Figure 8 shows an enlarged schematic view of a cross section of a fourth exemplary embodiment of a switch according to the invention;

[0032] Figures 9a to 9f shows a switch according to the invention in the form of a rotary switch; and

[0033] Figures 10a to 10f The switch according to the invention is shown in the form of a linear switch. DETAILED DESCRIPTION

[0034] exist Figure 1In the figure, the electric appliance according to the invention is partially shown in a cross-sectional view and is indicated as a whole by the reference numeral 2. In this example, the electric appliance 2 is designed as an electric tool, in particular as a random trajectory polisher or a random trajectory sander. The electric appliance 2 has a housing 4, which is made of plastic, for example. An electric motor 6 is located in the housing 4, and the electric motor is supplied with current by an electrical control unit (ECU) 8 via one or more lines 10. A cable 12 is used to supply current to the electric appliance 2 for supplying the motor 6, the control unit 8 and possible other electrical components of the electric appliance 2, and the cable is introduced into the rear part of the housing 4. The strands 14 of the cable 12 are connected to the control unit 8. The control unit 8, for example, includes an electrical control circuit for commutating the brushless electric motor 6.

[0035] When current is supplied to the motor 6 via line 10, it rotates the motor shaft 16, which rotational motion is transmitted to the backing pad 20 via the bevel gear 18. A reduction gear 22 may be disposed between the motor 6 and the bevel gear 18 to reduce the rotational speed and increase the torque. An eccentric 24 may be disposed between the bevel gear 18 and the backing pad 20 to implement an eccentric motion (e.g., random trajectory, rotational trajectory, or gear drive) of the backing pad 20. A polishing medium (e.g., a foam sponge, microfiber or wool pad) or an abrasive (e.g., sandpaper, textile abrasive) may be removably attached to the flat bottom side 26 of the backing pad 20, for example, by hook and loop fasteners.

[0036] The electric appliance 2 has a switch 30 according to the invention, which is arranged so that the user of the electric appliance 2 is at least indirectly accessible from the outside of the housing 4. The switch 30 can be used to switch on (the line 10 supplies energy to the motor 6) and disconnect (the power supply to the motor 6 is interrupted) the electric appliance 2. On the other hand, if the switch 30 also has a controller, the controller can be used to change the current supplied to the electric motor 6 via the line 10 using a potentiometer, thereby setting the rotation speed of the electric motor 6. The control unit 8 preferably has a circuit board (PCB) 32, on which the switch 30 is mounted and electrically contacted. The printed circuit board 32 is made of an electrically insulating material and is provided with conductive tracks and, in addition to the switch 30, is generally provided with other electrical components (e.g., plugs, capacitors, coils, diodes, transistors, thyristors, potentiometers). Of course, the electric appliance 2 can also be designed as any other electric appliance having an electrical load switched by the switch 30 according to the invention.

[0037] Figure 2A switch 30 known from the prior art is shown, which is currently used in an electric appliance 2, such as an electric tool. The switch 30 is designed as a sliding switch and has two switch contacts 34, 36 (so-called double slider contacts), which can be moved jointly at least between an off (neutral) position 38 and an on (effective) position 40. In the off position 38, the switch contacts 34, 36 are not electrically connected to a mating contact 42 of the switch 30. In the on position 40, the two switch contacts 34, 36 are electrically connected to the mating contact 42. The transition between the off position 38 and the on position 40 is also referred to as the ON switching point.

[0038] In the example shown, the switch 30 is designed as a toggle switch and has mating contacts 42, 46 on both sides to the disconnection position 38 in the direction of movement 44 of the switch 30. One mating contact 42 forms a so-called NO contact. The other mating contact 46 forms a so-called NC contact. Therefore, the switch 30 shown has two switching points, an ON switching point at the mating contact 42 and an OFF switching point at the mating contact 46. Such a switch 30 with a normally open contact 42 and a normally closed contact 46 is usually used in electric appliances, in particular in electric tools, so that once the switch contacts 34, 36 are electrically connected to the NC contact 46, a signal can be transmitted to the control unit 8 and the switch 30 can thus be safely disconnected. Therefore, from the disconnection position 38, the switch contacts 34, 36 can not only be moved to the connection position 40 against the normally open contact 42, but also can be moved to another (valid) position 48 in the direction of the normally closed contact 46.

[0039] The two switch contacts 34, 36 are interconnected in an electrically conductive manner and are part of a slider, the opposite end 50 of which is electrically connected to a slider track 52. The switch 30 thus makes contact between the slider track 52 and the normally open contact 42 (in position 40) or the normally closed contact 46 (in position 48) or breaks the contact (in position 38).

[0040] Figure 2 The known switch 30 shown in FIG. 3 has a problem in that when the electrical contact between the slider (switch contacts 34, 36) and one of the mating contacts 42, 46, in particular the normally open contact 42, is made or broken, since the current to be switched is relatively large, switching sparks, arcs and harmful electrical corrosion (e.g., contact corrosion) are generated at the switching point, which increases the contact resistance in an unfavorable manner and prolongs the switch-on stroke of the switch 3. In the known switch 30, the two switch contacts 34, 36 are made or broken at the same time, that is, contact corrosion occurs equally at the matching areas of the rising profiles 58, 60 of the two switch contacts 34, 36 or the mating contacts 42, 46. This leads to a change in the contact resistance and a relatively short life or low switching capacity of the switch 30.

[0041] In order to keep the contact resistance of the switch 30 as constant as possible throughout the service life of the switch and to extend the service life of the switch 30, the invention proposes that one or both of the switch contacts 34, 36 and / or the mating contacts 42, 46 are arranged and / or formed in such a way that during the transition between the disconnected (inactive) position 38 and one of the active positions 40, 48, the switch contacts 34, 36 successively enter into electrical contact with the matching mating contact 42 or 46 at the switching point of the switch 30, or successively break electrical contact. The following explanations on the design of the mating contact 42 at the ON switching point also apply in the same way to the design of the mating contact 46 at the OFF switching point, even if not explicitly mentioned. In the case of a toggle switch, the switch 30 is preferably designed so that the same switch contact 34 first contacts the rising contour 58 of the first mating contact 42 from the disconnected position 38 for connection and then contacts the rising contour 60 of the other mating contact 46 for disconnection.

[0042] The present invention can be implemented in a variety of ways. For example, the switch contacts 34, 36 are arranged in a direction of movement 44 of the switch 30 (see Figure 7 and Figure 8 ) can be changed to achieve a sequential or gradual contact of the switch contacts 34, 36 relative to the rising profiles 58, 60 of the mating contacts 42, 46. The design of the switch contacts 34, 36 or their switching surfaces can also be changed relative to the matching contact areas 62, 64, 66, 68 of the mating contacts 42 or 46, and the switching surfaces of the switch contacts 34, 36 are in contact with the matching contact areas 62, 64, 66, 68 of the mating contacts 42 or 46. In addition, the arrangement and / or design of the contact areas 62, 64, 66, 68 (or the rising profiles 58, 60) of the mating contacts 42 or 46 can be changed or adjusted relative to the switch contacts 34, 36 or their switching surfaces (see Figures 3 to 6 ).

[0043] The switch 30 according to the invention preferably has a regulator (not shown) for regulating the current supply to the electrical load, in particular for regulating the rotation speed of the electric motor 6 of the electric appliance 2. The switch 30 has a slider, which includes switch contacts 34, 36 designed as sliding contacts. The slider can be moved between a disconnect position 38 and an effective position 40, 48, in which the switch contacts 34, 36 are not electrically connected to the mating contacts 42, 46, and in which the switch contacts 34, 36 are electrically connected to the mating contacts 42 or the mating contacts 46. The switch contacts 34, 36 and / or the mating contacts 42, 46 are arranged and / or designed so that, at an ON switching point where the switch contacts 34, 36 transition between the disconnect position 38 and the connected position 40, the switch contacts 34, 36 are successively connected to the mating contact 42 or 46 to form electrical contact (when the switch 30 is moved to one of the effective positions 40, 48), or at an OFF switching point where the switch contacts 34, 36 transition between the disconnect position 38 and the effective disconnect position 48, the electrical contact is successively disconnected (when the switch is moved to the disconnect position 38).

[0044] The mating contacts 42, 46 and the slider track 52 are preferably applied as conductive tracks on the surface of a printed circuit board, for example the printed circuit board 32 of the control unit 8. The conductive material of the conductive tracks, for example copper, preferably has a thickness of less than 100 μm, in particular in the range of from 35 to 70 μm. Figures 3 to 8 In the drawing plane (first plane), the surfaces of the slider track 52 and the mating contacts 42, 46 extend parallel to the surface of the PCB 32. The movement direction 44 of the switch 30 extends in the drawing plane or parallel to the drawing plane. Figure 3 and Figure 4 In the example of the invention, it is suggested that the switch contacts 34, 36 are spaced apart in a first plane. The switch contacts 34, 36 are also aligned in a second plane 54, which is transverse to the movement direction 44 of the switch 30 and perpendicular to the first plane. The mating contacts 42 and 46 have, on their ends facing the disconnection position 38 of the switch 30, respectively, a rising contour 58 and 60 in a third plane 56, which is inclined to the movement direction 44 of the switch 30 and extends perpendicular to the first plane. The second plane 54 and the third plane 56 extend obliquely to each other.

[0045] Based on the rotary switch Figures 9a to 9f And based on the linear switch Figures 10a to 10f The movement of the switch 30 from the effective OFF switch position to the ON position is explained in more detail below. Figure 9a and Fig.10aIn both cases, the switch 30 is in the effective OFF switch position. If the switch 30 or the slide with the switch contacts 34, 36 is moved in the marked actuation direction 44 by about 1 mm (see Figure 9b and Fig.10b ), then reaches the end of the NC mating contact 46. When the switch contact 36 is just disconnected from the NC mating contact 46, the first switch contact 34 is still just connected to the NC mating contact 46. This position corresponds to Figures 2 to 8 If the switch 30 or the slide with the switch contacts 34, 36 is moved a further 1.1 mm from the effective OFF switch position (see Fig.9c and Fig.10c ), that is, a total movement of about 2.1 mm, then the beginning of the NO contact 42 is reached. When the other switch contact 36 has not yet been connected to the NO matching contact 42, the first switch contact 34 has been connected to the NO matching contact 42. This position corresponds to Figures 2 to 8 The switch 30 in the example thus has an ON travel of 2.1 mm. If the switch 30 or the slide with the switch contacts 34, 36 is moved a further 0.6 mm from the effective OFF switch position (see Figure 9d and Fig.10d ), i.e. a total movement of about 2.7 mm, the switch 30 is in the ON state. From this point on, the controller (potentiometer) of the switch 30 begins to adjust the rotation speed (minimum speed) of the motor 6. If the switch 30 or the slide with the switch contacts 34, 36 moves a further 4.8 mm from the effective OFF switch position (see Fig.9e and Fig.10e ), i.e. a total movement of about 7.5 mm, the switch 30 is still in the ON state. At this point, the control range of the controller of the switch 30 ends and the rotation speed of the motor 6 is set to its maximum value (maximum speed). Therefore, this 4.8 mm is the control range within which the rotation speed of the motor 6 can vary between the minimum and maximum values. If the switch 30 or the slider with the switch contacts 34, 36 moves another 0.8 mm or 1.0 mm from the effective OFF switch position (see Figure 9f and Fig.10f ), that is, a total movement of about 8.3 mm or 8.5 mm, the switch 30 is at the end of its travel. Because the rising contours 58, 60 of the mating contacts 42, 46 are inclined relative to the actuation direction 44, the switch contacts 34, 36 successively make contact with or disconnect the electrical connection with the mating contacts 42, 46.

[0046] Figure 4It is clearly shown that when the switch 30 is closed at the ON switching point 40, the first switch contact 34 first contacts the first contact area 62 of the inclined rising profile 58, which protrudes further in the direction of the open position 38 of the switch 30, before the other switch contact 36 contacts the other contact area 66 of the rising profile 58. Thus, at the OFF switching point 48, the first switch contact 34 first contacts the first contact area 64 of the inclined rising profile 60, which protrudes further in the direction of the open position 38 of the switch 30, before the other switch contact 36 contacts the other contact area 68 of the rising profile 60. When the second switch contact 36 contacts the mating contact 42; 46, the electrical connection between the slider track 52 and the matching mating contact 42; 46 is already established, so that no arc and discharge can occur at the other switch contact 36.

[0047] Of course, it is also conceivable that the second plane 54 is inclined with respect to the movement direction 44 of the switch 30 and extends perpendicularly to the first plane (see Figure 7 and Figure 8 ). The third plane 56 in which the rising contours 58, 60 of the mating contacts 42, 46 are located can then extend transversely or obliquely to the movement direction 44 of the switch 30 and perpendicularly to the first plane. Here, the second plane 54 and the third plane 56 also extend obliquely to each other. Figure 7 and Figure 8 In the example of FIG. 4 , the slide is designed with an asymmetrical shape, wherein one of the switch contacts 34 , 36 projects further in the direction of the mating contact 42 in the direction of movement 44 and is therefore designed to be longer or more advanced in this direction. The rising contour 58 at the ON switching point 40 and the rising contour 60 at the OFF switching point 48 are straight. Figure 7 In a variant of the present invention, the first switch contact 34 first makes contact with the NO contact 42, while the other switch contact 36 first makes contact with the NC contact 46. For this design, the process of establishing contact at the switching points 40, 48 is also sequential.

[0048] exist Figure 8 In the variant shown in , the rising contour 60 of the mating contact 46 is stepped so that the upper step with the contact area 64 protrudes further in the direction of the slide or the mating contact 42. Despite the asymmetry of the slide, this ensures that the first switching contact 34 first contacts the mating contact 42 not only at the ON switching point 40, but also at the OFF switching point 48 with the mating contact 46.

[0049] exist Figure 5 and Figure 6In the example of , the switch contacts 34, 36 are spaced apart in a first plane (drawing plane) and aligned in a second plane 54, which extends transversely to the movement direction 44 of the switch 30 and perpendicularly to the first plane. Relative to the second plane 54, the mating contacts 42, 46 have a stepped rising contour 58, 60 at their ends facing the disconnection position 38. In particular, one contact area 62, 64 assigned to the first switch contact 34 protrudes further in the direction of the slide than the other contact areas 66, 68 assigned to the other switch contact 36. The second plane 54 can also extend obliquely to the movement direction 44 of the switch 30 (see Figure 8 ), the switch contacts 34, 36 are aligned in the second plane 54. Preferably, each switch contact 34, 36 is assigned one step of each stepped rising profile 58, 60.

[0050] When the switch 30 is moved to the effective ON switching point, the first switch contact 34 first comes into contact with the contact area 62 of the first step of the rising profile 58, which protrudes further toward the disconnected position 38 of the switch 30, before the further switch contact 36 comes into contact with the further contact area 66 of the further step of the rising profile 58. Correspondingly, when the switch 30 is moved to the effective OFF switching point, the first switch contact 34 first comes into contact with the contact area 64 of the first step of the rising profile 60, which protrudes further toward the disconnected position 38 of the switch 30, before the further switch contact 36 comes into contact with the further contact area 68 of the further step of the rising profile 60.

[0051] Preferably, the printed circuit board (for example the printed circuit board 32 of the control unit 8 of the electric appliance 2) has a recess or groove 70 between the two mating contacts 42, 46 in the area corresponding to the disconnected position 38 of the switch 30 (see Figure 6 ), the mating contacts 42, 46 and the slider track 52 are applied as conductive tracks to the printed circuit board. During operation of the switch 30, particles and wear (e.g., material transfer due to electrical corrosion or mechanical material wear) can form inside the switch 30, which can cause leakage currents. These particles and wear can be removed from the area of ​​the disconnection position 38 by the grooves 70 provided in the circuit board 32. This increases the isolation value of the switch 30.

[0052] In order to further extend the service life of the switch 30 and improve the switching capacity of the switch 30, it is advantageous that at least the first contact area 62 (see FIG. 1 ) where the first switch contact 34 first makes electrical contact with the mating contact 42 Figure 4 , Figure 5 and Figures 10a-10f), the rising profile 58 of the mating contact 42 is provided with an additional coating of an electrically conductive material, in particular copper. In the same way, at least in the first contact region 64 in which the first switch contact 34 first makes electrical contact with the mating contact 46, the rising profile 60 of the mating contact 46 can also be provided with an additional coating of an electrically conductive material, in particular copper. Preferably, the additional coating has a thickness of more than 100 μm, in particular of at most 1 mm, preferably of about 0.2 mm. The additional coating can be designed, for example, as a welded or soldered contact plate. Such a switch 30 is also suitable for higher currents and powers, which occur temporarily, for example, when the capacitor of the control unit 8 must be charged during the first switch-on process of a series of switching cycles.

[0053] The switch 30 according to the present invention can be designed as a linear slide switch (see Figures 10a to 10f ), wherein the mating contacts 42, 46 are linear and the sliding axes of the switch contacts 34, 36 extend parallel to the longitudinal extension of the mating contacts 42, 46. Alternatively, the switch 30 can also be designed as a rotary slide switch (see Figures 9a to 9f ), wherein the mating contacts 42, 46 are arranged on a circular arc and the rotation axis of the switching contacts 34, 36 passes through the center point of the circular arc.

Claims

1. A switch (30), which is an electrical switch for an electric appliance (2), comprising at least two switch contacts (34, 36) that can be moved together, wherein the switch contacts (34, 36) can be moved between an off position (38) and an on position (40), wherein in the off position (38), the switch contacts (34, 36) are not electrically connected to a first mating contact (42) of the switch (30), and in the on position (40), the switch contacts (34, 36) are electrically connected to the first mating contact (42); in, The switch contacts (34, 36) and / or the first mating contact (42) are arranged and / or designed so that when the switch (30) is switched between the disconnected position (38) and the connected position (40), the switch contacts (34, 36) successively enter into electrical contact with the first mating contact (42) or successively break electrical contact. Features: The switch (30) is designed as a toggle switch and has a first mating contact (42) and a second mating contact (46) on both sides of an off position (38) along a movement direction (44) of the switch (30), and The printed circuit board (32) has a notch or groove (70) in an area corresponding to the open position (38) of the switch (30).

2. The switch (30) according to claim 1, characterized in that: The switch (30) is designed as a signal switch which interacts with the control electronics of the electric device (2) and switches a signal current for the control electronics, which in turn switches an electrical load of the electric device (2).

3. The switch (30) according to claim 1 or 2, characterized in that: The switch (30) has a regulator for regulating the current supply to the electric load of the electric appliance (2).

4. The switch (30) according to claim 1 or 2, characterized in that: The switch contacts (34, 36) are arranged spaced apart in a first plane, which extends parallel to an extension plane of the first mating contact (42) and parallel to a movement direction (44) of the switch (30); The switch contacts (34, 36) are aligned in a second plane (54) that is transverse or oblique to the direction of movement (44) of the switch (30) and perpendicular to the first plane; and The first mating contact (42) has a rising contour (58) at its end facing the disconnection position (38), which extends in a third plane (56) transversely or obliquely to the movement direction (44) of the switch (30) and perpendicular to the first plane, The second plane (54) and the third plane (56) extend obliquely to each other.

5. The switch (30) according to claim 1 or 2, characterized in that: The switch contacts (34, 36) are arranged spaced apart in a first plane, which extends parallel to an extension plane of the first mating contact (42) and parallel to a movement direction (44) of the switch (30); The switch contacts (34, 36) are aligned in a second plane (54) that is transverse or oblique to the direction of movement (44) of the switch (30) and perpendicular to the first plane; and The first mating contact (42) has a stepped rising contour (58) at its end facing the disconnection position (38) relative to the second plane (54).

6. The switch (30) according to claim 5, characterized in that: Each switching contact (34, 36) is assigned one step of each stepped rising profile.

7. The switch (30) according to claim 1 or 2, characterized in that: The first mating contact (42) or the first mating contact (42) and the second mating contact (46) are both formed as conductive tracks on the printed circuit board (32).

8. The switch (30) according to claim 1 or 2, characterized in that: At least in a contact region (62) where the first switching contact (34) first makes electrical contact with the first mating contact (42), the rising contour (58) of the first mating contact (42) is provided with an additional coating of an electrically conductive material.

9. The switch (30) according to claim 8, characterized in that: The additional coating has a thickness greater than 100 μm and less than 1 mm.

10. The switch (30) according to claim 1 or 2, characterized in that: The first mating contact (42) is shaped like a circular arc, wherein the switching contacts (34, 36) are movable about a rotation axis which passes through the center of the first mating contact (42) in the circular arc shape.

11. The switch (30) according to claim 1 or 2, characterized in that: The first mating contact (42) is linear, wherein the switching contacts (34, 36) are movable on a sliding axis which extends parallel to the longitudinal extension of the first mating contact (42).

12. The switch (30) according to claim 1 or 2, characterized in that: The switch (30) has two switch contacts (34, 36).

13. The switch (30) according to claim 1, characterized in that: The electric appliance (2) is an electric tool.

14. The switch (30) according to claim 2, characterized in that: The electric load of the electric device (2) is an electric motor (6) of an electric tool.

15. The switch (30) according to claim 3, characterized in that: The regulator is used to adjust the rotation speed of an electric motor (6) of an electric tool.

16. The switch (30) according to claim 7, characterized in that: The conductive tracks on the printed circuit board (32) have a thickness of the conductive material of the conductive tracks that is less than 100 μm.

17. The switch (30) according to claim 16, characterized in that: The conductive tracks on the printed circuit board (32) have a thickness of the conductive material of the conductive tracks in the range from 35 to 70 μm.

18. The switch (30) according to claim 8, characterized in that: The conductive material is copper, silver or gold.

19. The switch (30) according to claim 9, characterized in that: The additional coating had a thickness of 0.2 mm.

20. An electric device (2) having a switch (30) for switching the electric device (2) on and off, The switch (30) has a slide having at least two switch contacts (34, 36) that are switched together, the slide being movable between an off position (38) and an on position (40), wherein in the off position (38) the slide is not electrically connected to a first mating contact (42) of the switch (30), and in the on position (40) the slide is electrically connected to the first mating contact (42), Features: The switch (30) is a switch according to any one of the preceding claims.

21. The electric device (2) according to claim 20, characterized in that: The electric appliance (2) is an electric tool.

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