Quick-acting switch

Abstract

The invention relates to a snap-action switch (100), comprising a housing (1) and an actuating lever (2) having two switching positions, having at least one contact bridge (31, 32) for electrically connecting at least one first contact pair (23, 24) in the switching position and snap-action springs (8, 9) which are supported in a pretensioned manner substantially symmetrically on an actuating element (3) and the actuating lever (2), the line of action of the snap spring can be moved by the actuating element (3) such that the actuating lever (2) can be quickly switched from a first switching position, in which the actuating lever (2) is substantially in the rest position, to a second switching position, in which the actuating lever (2) is substantially in the actuated position, and wherein the snap switch (100) further comprises a forced opening device by which the actuating lever (2) can be quickly switched from the first switching position to the second switching position, by which the actuating lever (2) is substantially in the actuated position, when a forced opening force is exceeded. The forcible actuation lever (3) is switched at least from a first switching position into a second switching position, the at least one contact bridge (31, 32) having at least two contact points (17, 18, 19, 20) at one end and at the other end for electrically contacting the first contact pair (23, 24) in parallel, each contact point (17, 18, 19, 20) being designed to completely switch the nominal electrical power of the snap-action switch (100).

Description

Technical Field

[0001] The invention relates to a snap-action switch according to the preamble of claim 1 . Background Art

[0002] Snap-action switches are generally known in the prior art and generally comprise a housing and a contact bridge with two switching positions, which can be switched by an actuating lever and serves to electrically connect fixed contacts, in particular to electrically connect at least one first contact pair in a first switching position and to electrically connect at least one second contact pair in a second switching position. Two snap-action springs are supported in a prestressed manner substantially symmetrically on the actuating element and the actuating lever, the lines of action of which can be moved by the actuating element so that the actuating lever can be switched rapidly from a first switching position, in which the actuating lever is substantially in the rest position, to a second switching position, in which the actuating lever is substantially in the actuated position.

[0003] A common feature of snap-action switches is that they employ a bistable snap-action spring arrangement which results in a rapid switching movement when a certain switching point is exceeded. This rapid switching movement is intended to minimize flashovers and thus damage to the contact elements. To provide this function, it is not important whether the spring arm is formed integrally with the contact bridge or is designed as a separate component.

[0004] Fig. 9 A snap action switch known in the prior art is shown.

[0005] The snap-action switch shown comprises a housing 1 of rectangular cross section for accommodating the various components of the snap-action switch. An actuating rod 2 is arranged in the center of the housing 1, which has a stop step inside the housing 1, which in the rest position of the actuating rod 2 abuts against the inside of the wall of the housing 1. A compression spring 4 presses the actuating rod 2 upwards into its rest position so that the stop step 3 makes reliable contact. In the region of the compression spring 4, the actuating rod 2 is guided in a sleeve-like accommodation, and at the end opposite to the compression spring 4, the actuating rod 2 is guided in a recess of the housing 1.

[0006] At approximately half the height of the longitudinal extension of the actuating rod 2 located in the housing 1, the actuating rod 2 has two diametrically opposed receiving recesses 7, i.e., in the exemplary embodiment, two mirror-opposite receiving recesses 7, each of which is designed to support on one side a V-shaped snap-action spring 8, 9. The contact carrier 10 is held on the actuating rod 2 in a prestressed manner by the snap-action springs 8, 9.

[0007] The other ends of the snap-action springs 8, 9 are received in receiving recesses 11, 12 of insulating spacers 13, 14, respectively. The spacers 13, 14 hold the upper contact arm 15 and the lower contact arm 16 so that they are aligned parallel to each other and spaced apart from each other. When viewed from above, the contact arms 15, 16 are approximately O-shaped. This holding is achieved by arranging the snap-action springs 8, 9 in a pre-tensioned manner between the actuating rod 2 and the spacers 13, 14 so that the spacers 13, 14 are pressed against the contact arms 15, 16 and thus fix the spacers 13, 14 in their position.

[0008] The contact arms 15, 16 have contact areas 17, 18, 19, 20 arranged on the end sides, wherein the contact areas 17, 18, 19, 20 arranged on the contact arms 15, 16 are respectively assigned relatively arranged fixed contacts 21, 22, 23, 24, so that one contact arm 15, 16 in the actuated position of the snap-action switch and the other contact arm 16, 15 in the rest position of the snap-action switch are in contact with the fixed contacts 21, 22, 23, 24 assigned to them and are connected to each other in an electrically conductive manner.

[0009] The first contact region 17 is assigned with a first fixed contact 21, and the second contact region 18 is assigned with a second fixed contact 22. Therefore, the first fixed contact 21 and the second fixed contact 22 can be electrically connected to each other through the upper contact bridge 15, and form a first contact pair. Similarly, the third contact region 19 is assigned with a third fixed contact 23, and the fourth contact region 20 is assigned with a fourth fixed contact 24, so that the third fixed contact 23 and the fourth fixed contact 24 can be electrically connected to each other through the lower contact bridge 16, and form a second contact pair.

[0010] Since in such snap-action switches, thermal overloading of the contact parts may lead to undesired welding of the contact area of ​​the contact arm to the contact of the contact pair (i.e. the fixed contact), lever elements for forced opening are provided in some applications. The DIN EN 60947-5-1 standard stipulates in Appendix K that standardized snap-action switches must have such a rigid, shape-locking forced opening device in addition to the snap-action spring mechanism, so that for safety reasons, the normally closed contact position can be reliably opened when the actuating element of the snap-action switch is operated. The forced opening device can open the contact parts welded due to overcurrent by applying appropriate force. These lever elements can usually be rotated by a switch rod, one end of which can be placed on the contact carrier or contact arm, and when sufficient force is applied to the switch rod, these lever elements cause the contact area to be pushed away from the contact pair and thus cause the switch position to be forced open. In order to realize one of the switch positions as a static position, such as Fig. 9As shown in the example of , an additional spring element can be integrated into the snap-action switch, so that the position of the contact carrier in the rest position is stabilized by the force of the spring element.

[0011] Known snap-action switches are already very reliable and can be used in safety-critical applications. However, a disadvantage is that known snap-action switches can fail electrically due to various factors, i.e. the contact arm cannot establish an electrically conductive connection between the fixed contacts or can only establish an insufficient electrically conductive connection. Causes of such failures can be excessive contact resistance due to dirt deposits or burn-in on the contacts, breakage of the snap-action spring or the contact bridge due to mechanical and / or thermal loads. Summary of the invention

[0012] It is therefore an object of the present invention to improve the known snap-action switches.

[0013] This object is achieved by a snap-action switch having the features of claim 1. Advantageous developments are the subject matter of the dependent claims and the following description.

[0014] The snap-action switch according to the present invention comprises a housing and an actuating rod having two switching positions, the actuating rod having at least one contact bridge for electrically connecting at least one first contact pair in the switching position and a snap-action spring supported on the actuating element and the actuating rod in a pre-tensioned manner and in a substantially symmetrical manner, the line of action of the snap-action spring being movable by the actuating element so that the actuating rod can be rapidly switched from a first switching position in which the actuating rod is substantially in a stationary position to a second switching position in which the actuating rod is substantially in an actuating position, wherein the snap-action switch further comprises a forced opening device, by which the actuating element is forced to switch at least from the first switching position to the second switching position when the forced opening force is exceeded, wherein at least one contact bridge has at least two contact points for electrically contacting the first contact pair in parallel at one end and the other end, respectively, wherein each contact point is designed to fully switch the rated electrical power of the snap-action switch.

[0015] An embodiment according to the invention provides electrical and mechanical redundancy, so that even in the event of a failure of up to two contact points, the snap-action switch is still available. The contact bridge can be realized by electrically and mechanically parallel electrical conductors, wherein, for example in the case of two parallel electrical conductors, an electrical or mechanical failure of one of the conductors can be compensated in this way, i.e. in this case an electrical or mechanical failure of both contact points assigned to the conductor can be compensated.

[0016] Snap-action switches can be designed as normally closed contacts or normally open contacts, wherein the idle position of the actuating lever determines whether the snap-action switch is a normally closed or normally open contact.

[0017] In an advantageous embodiment, the snap-action switch has two contact bridges for electrically connecting at least a first contact pair and at least a second contact pair, wherein the contact points of the second contact bridge are also designed to fully switch the rated electrical power of the snap-action switch.

[0018] By using two contact bridges, a double-pole normally closed contact or a double-pole normally open contact can be realized.

[0019] If the snap-action switch is designed such that a first contact pair is connected in a first switching position and a second contact pair is connected in a second switching position, the snap-action switch is implemented as a normally closed contact or a normally open contact depending on the fixed contact contacted from the outside.

[0020] In an advantageous embodiment, the snap-action switch comprises a housing and an actuating rod with two switching positions, the actuating rod having at least two contact bridges and a snap-action spring, the at least two contact bridges being used to electrically connect at least one first contact pair in a first switching position and to electrically connect at least one second contact pair in a second switching position, the snap-action spring being supported in a pre-tensioned manner on the actuating element and the actuating rod in a substantially symmetrical manner, the line of action of the snap-action spring being displaceable by the actuating element so that the switch rod can be quickly switched from a first switching position in which the actuating rod is substantially in a rest position to a second switching position in which the actuating rod is substantially in an actuated position, wherein the snap-action switch further comprises a forced opening device by means of which the actuating element is forced to switch at least from the first switching position to the second switching position when the forced opening force is exceeded, characterized in that the at least two contact bridges have at least two contact points at one end and at the other end, respectively, the at least two contact points being used to electrically connect the first contact pair in parallel in the first switching position and to electrically connect the second contact pair in parallel in the second switching position, wherein each contact point is designed to completely switch the rated electrical power of the snap-action switch.

[0021] The embodiment of the contact bridges with at least two contact points each has the advantage that in this way an electrical parallel contacting of the contact point pairs can be achieved. Thus, each switching bridge can compensate for the failure of one switching point of each contact part, which means that a contact part can fail at one end and at the other end of the contact bridge, for example due to contamination, burning or mechanical defects, but still maintain the function of the snap-action switch. Thus, additional redundancy is provided and the switching reliability is increased. The availability of the snap-action switch is increased.

[0022] In the embodiment with two contact points at each bridge end, the following contact options are available when the components of the contact bridge are cross-contacted, i.e. when the contact bridge is designed such that all contact points are electrically conductively connected to one another: Ideally, two contact points are contacted on both sides. If one of the contact points on the input side and / or the output side fails in any way, it is always the case that at least one contact point can function normally.

[0023] In this article, the term "contact point" is only used to distinguish different contact positions. Therefore, the contact point is not necessarily designed to be point-shaped, but can also be designed to be linear or flat.

[0024] The term "contact pair" is also used only for distinction. A contact pair is always a contact portion of an associated fixed contact arranged at opposite ends of a switching bridge. A contact pair comprises at least two contact portions, i.e. a pair of contact portions, but may also comprise a plurality of contact portions. Preferably, however, the fixed contacts at both ends of the contact bridge comprise the same number of contact portions.

[0025] In an improved example of a snap-action switch, each contact bridge is formed integrally. In this context, "integrally" means that the contact bridge is made entirely of the same material, which has both energy transfer properties and static load-bearing properties. Therefore, compared with the prior art, the contact bridge is characterized by a simple structure. For this purpose, the material of the contact bridge is preferably designed to be both conductive and load-bearing.

[0026] Metals or metal alloys with spring properties are particularly suitable for the design of the contact bridge. For example, spring steel can be used, while bronze, brass, nickel silver or copper alloys are preferred due to their higher electrical conductivity. Copper beryllium alloys are particularly preferred due to their particularly good electrical and thermal conductivity and mechanical properties. Copper nickel silicon alloys can also be used due to the good electrical and thermal conductivity that can be achieved and the good mechanical properties. This design makes it possible for the contact bridge to be mechanically stable with a small material cross section and to be of sufficient size for the current to be switched.

[0027] In a preferred embodiment, the contact bridge is designed in the form of a double H-bridge, wherein each H-bridge has two bridge arms on both sides of the actuating lever and at least one crosspiece.

[0028] In this case, "H-bridge" means that the contact bridge has an "H"-shaped structure. This structure provides two parallel contact paths for contacting a pair of fixed contacts, wherein a lateral contact can be simultaneously made from one arm of the H-bridge to the other arm of the H-bridge via a cross-piece.

[0029] The H-bridge design also has the advantage that the individual bridge arms of the H-bridge can be designed flexibly in the actuation direction, so that the height of the individual contact points at one end of the bridge can be compensated. For example, the H-bridge can be used to generate height differences caused by particles between the contact parts at one end of the H-bridge.

[0030] The contact bridge can also be designed so that on both sides of the actuating rod, one bridge arm is designed to be the leading one, while the other bridge arm is designed to be the trailing one. By this design, a contact bridge can be realized in which the contact points arranged on the leading bridge arm are mainly affected by the switching arc and the related burning loss.

[0031] In this context, "leading" means that the leading bridge arm of the switching bridge or the contact point arranged on the leading bridge arm first contacts the fixed contact in the closing direction of the contact bridge and establishes a conductive connection. Only when a conductive connection already exists via the leading bridge arm does the trailing contact point contact the fixed contact.

[0032] Conversely, when opening, this means that the trailing arm of the contact bridge is electrically disconnected first, followed by the leading arm. Since the leading contact switches a larger current than the trailing contact, it is ensured that the switching arc occurs only at the leading contact point and only the leading contact point has a tendency to weld to the fixed contact.

[0033] Therefore, in a preferred embodiment, the material of each contact point can be adapted to this. In particular, the contact point on the leading bridge arm can be designed to be more resistant to burning. Suitable materials for the contact point of the leading bridge arm are, for example, silver, gold, or a silver alloy or a gold alloy.

[0034] In contrast, the trailing bridge arm may have contacts made of a highly conductive but less wear-resistant material, such as gold.

[0035] In case of mixed loads, the leading contact switches the higher current and loads the load accordingly. When the contact resistance of the leading contact becomes too high at a lower current, the trailing contact switches. Since the trailing contact does not switch the high load, it can have a contact material that is more suitable for low loads.

[0036] In another embodiment, the contact bridge is designed to be spring-elastic. This allows manufacturing tolerances to be compensated and, for example, a reliable contact can be achieved by height compensation in the presence of particles. In addition, the spring-elastic design of the contact bridge can support the opening of the snap-action switch. The metals and metal alloys mentioned above for the design of the contact bridge are particularly suitable materials.

[0037] Reliable contacting can also be achieved if the contact bridges are designed in such a way, the contact points are arranged and the contact points are arranged relative to the contact pairs in such a way that the contacts are self-cleaning.

[0038] For example, self-cleaning of the contacts can be achieved by designing the contact points and the contact pairs and arranging them relative to one another in such a way that a lateral movement occurs between the contact points and the contact pairs at least when the contacts are closed.

[0039] This traverse movement can remove and clean deposits, for example caused by burn-off, during the traverse movement, thus ensuring reliable contact at all times.

[0040] For example, if the contact bridge is made of a spring-elastic material, then when an electrical connection already exists, i.e. when the contact point is already in contact with the contact pair, further movement of the contact bridge in the closing direction can lead to a lateral movement of the contact point and the contact pair relative to each other, thereby grinding off the deposits and simultaneously pushing them away from the contacts.

[0041] In one embodiment, at least two contact bridges can each be assigned a reinforcement device in the opening direction. The reinforcement device can make the contact bridge itself smaller in size, but still have sufficient stability. Such a reinforcement device can be useful in particular in the opening direction, because welds that may be caused by thermal loads must be loosened in this direction. At the same time, if the reinforcement device is used only in the opening direction, on the one hand, flexibility in the closing direction can be achieved, and on the other hand, sufficient stability in the opening direction can be ensured.

[0042] For example, such a reinforcement device can be arranged on the actuating lever, in particular formed integrally therewith.

[0043] Alternatively, a multi-component design is also conceivable, in which the reinforcement device is designed as a separate component.

[0044] By arranging the reinforcement device and in particular by forming the reinforcement device integrally with the actuating lever, an embodiment which is particularly space-saving and particularly easy to implement in terms of production technology can be achieved.

[0045] For example, the reinforcement device can be designed as a molded part extending from the actuating rod in the extension direction of the contact bridge, in particular in the form of a reinforcement arm. Such a molded part can be realized particularly easily during the production of the actuating rod, for example in plastic injection molding, and produced in the necessary dimensions.

[0046] Preferably, at least in the non-contacted state, the molded part supports at least 1 / 5 of the bridge arm in the region of the protruding actuating rod, preferably at least 1 / 4 of the bridge arm, more preferably at least half of the bridge arm, and particularly preferably at least 3 / 4 of the bridge arm. The larger the contact area of ​​the contact bridge arm on the molded part, the greater the supporting effect in the opening direction, so that it may also make sense to support more than 3 / 4. By increasing the contact surface, the excess (i.e. the length of the contact bridge protruding from the molded part) is reduced, thereby achieving a stronger supporting effect. As a result, the opening force acting on the actuating rod is transmitted to the contact bridge over a larger area, while the length of the contact bridge that protrudes freely is also reduced. The forces that resist the opening action (for example due to the welding of the contact part to the fixed contact) act through a smaller lever arm, so that the risk of bending of the contact bridge is reduced.

[0047] In a preferred embodiment, the shape of the molded parts is such that they can pre-tension the contact bridge. Therefore, a preferred embodiment is that the molded part on the actuating lever bends the contour of the contact bridge so that it advantageously has a defined pre-tension.

[0048] By prestressing the contact bridge, several advantages can be achieved. Since the contact bridge is brought into a defined position by the molding, manufacturing tolerances of the contact bridge can be compensated without reworking. In addition, the contact bridge can have a defined prestressing force, so that a greater force is immediately available in the opening direction to open the contacts.

[0049] In this context, the contour of a bridge arm refers in particular to the course of the bridge arm in a side view.

[0050] In particular, the contact bridge can be designed as a stamped and bent part. Stamped and bent parts can be produced cost-effectively and with high quality.

[0051] Alternatively, other manufacturing methods can also be used, especially for small batch production. For example, different cutting methods can be used, such as by water jet or laser, followed by a bending step.

[0052] In order to be able to reliably transmit the opening force specified for forcibly opening the rest position, the molded part is dimensioned so that an opening force of at least 10 N can be transmitted to the contact point of the bridge arm, preferably an opening force of 20 N can be transmitted to the contact point of the bridge arm, and more preferably an opening force of 30 N can be transmitted to the contact point of the bridge arm. In this way, it can be ensured that the snap-action switch according to the present application also complies with the DIN EN 60947-5-1 standard. However, the molded part can also transmit a higher forced opening force than the 20 N required by the standard, so that in particular a force transmission of more than 30 N can be achieved.

[0053] For example, the actuating lever can be designed in at least two parts, so that the contact bridge can be inserted between the two parts of the actuating lever and thus fixed there.

[0054] In an alternative embodiment, the contact bridge is injection-molded together with the actuating rod. This embodiment has the advantage that it can be realized particularly cost-effectively, reduces the number of components of the snap-action switch and provides particularly good fixing of the contact bridge since the contact bridge is fixed in the region of the actuating rod in a form-locking and force-locking manner.

[0055] All contacts on the contact bridge and in the fixed contact can be designed as cylindrical, flat or spherical / elliptical (contact rivets). In the case of spherical contacts, the contact surface is point-shaped, in the case of cylindrical contacts, the contact surface is linear, and in the case of double-sided contacts, the contact surface is flat.

[0056] The self-cleaning of the switch points can be designed to operate in a push or pull manner. Depending on the angle at which the contact points and the contact pairs intersect, a push or pull relative movement is performed between the contacts. Further details will be found in the exemplary embodiments described below.

[0057] Advantageous embodiments and variants of the invention are given in the dependent claims and in the following description. The features listed individually in the dependent claims can be combined with one another in any technically reasonable manner and can also be combined with the features explained in more detail in the following description and can represent further advantageous variants of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Hereinafter, the present invention will be described in detail based on exemplary embodiments with reference to the accompanying drawings.

[0059] Figure 1 A first exemplary embodiment of a snap-action switch according to the application is shown in a simplified diagram.

[0060] Figure 2 A schematic diagram of an actuating lever with a first contact bridge and associated fixed contacts is shown.

[0061] Figure 3 a) to c) show the Figure 2 The closing process of the contact bridge of the snap-action switch.

[0062] Figure 4 a) to c) show Figure 3 The opening process of the contact bridge.

[0063] Figure 5 a) and 4b) show the contact bridge in closed ( Figure 5 a)) and open ( Figure 5 b) Alternative embodiment.

[0064] Figure 6 A third exemplary embodiment of a contact bridge is shown.

[0065] Figure 7 A fourth exemplary embodiment of a contact bridge is shown.

[0066] Figure 8 a) and 8b) show contact bridges with leading and trailing bridge arms.

[0067] Fig. 9 A snap action switch according to the prior art is shown (illustrated). DETAILED DESCRIPTION

[0068] In the drawings, unless otherwise specified, the same reference numerals denote the same or corresponding components having the same functions.

[0069] Figure 1A first exemplary embodiment of a snap-action switch 100 according to the present application is shown.

[0070] In the illustrated figure, the snap-action switch 100 is simplified and shown as an open housing so that the functions of the various components located in the snap-action switch 100 can be more clearly seen. The basic function of the snap-action switch 100 is realized by an actuating lever 2 having at least two switching positions, wherein the actuating lever 2 can be actuated in a first switching position (e.g. Figure 1 The actuator rod 2 is switched between a first switch position and a second switch position, in which the actuator rod 2 is in a position that can move relative to the first switch position in the direction of the actuator element 3. The switch element 3 is connected to the actuator rod 2 via two snap-action springs 8 and 9 that are supported in parallel on the switch element 3 and the actuator rod 2. Therefore, operating the actuator element 3 changes the characteristic curves of the snap-action springs 8 and 9, so that the actuator rod 2 quickly switches from the first switch position to the second switch position. In this exemplary embodiment, the actuator element 3 is also acted upon by the compression spring 4, so that Figure 1 The first switching position shown is stabilized by the compression spring 4 .

[0071] Figure 1 The snap-action switch 100 shown also includes a forced opening device consisting of a first forced opening rod 5 and a second forced opening rod 6. One end of the forced opening rod 5, 6 is supported on the circumferential shaft ring of the actuating rod 2, and the other end thereof is slidably mounted in the housing of the snap-action switch 100. If a predetermined actuating force is applied by the actuating element 3, the actuating element 3 will contact the forced opening rod 5, 6, and by tilting the forced opening rod 5, 6, the actuating element 3 is indirectly mechanically coupled to the actuating rod 2 via the forced opening rod 5, 6, thereby achieving mechanical forced switching when the actuating rod 2 cannot be quickly switched from the first switch position to the second switch position.

[0072] As has already been shown with reference to the prior art, such a forced opening device may be required if the contacts of the snap-action switch 100 are welded together in the switching position (in the present embodiment, the first switching position), for example due to thermal load, and the snap-action springs 8, 9 are therefore unable to release the contacts and change the switching position.

[0073] exist Figure 1 In the snap-action switch 100 shown, the first contact bridge 31 and the second contact bridge 32 are arranged on the actuating rod 2, wherein Figure 1 In the first switching position of the actuating lever 2 shown, the first contact bridge 31 is not in contact with the fixed contacts 21, 22 assigned to it, and the second contact bridge 32 electrically connects the third fixed contact 23 and the fourth fixed contact 24 to one another. In order to make contact with the corresponding fixed contacts 21, 22, 23, 24, the contact bridges 31, 32 have contact points arranged on their end sides, which reinforce the contact bridges and make them wear-resistant.

[0074] Figure 2 The schematic diagram shows the actuating lever 2 with the first contact bridge 31 and the associated fixed contacts 21 , 22 in the second switching position.

[0075] The exemplary embodiments described below for the first contact bridge 31 also apply mutatis mutandis to the second contact bridge 32 .

[0076] Figure 2 The illustration in FIG. 1 is greatly simplified and is essentially intended to explain the functioning principle of the illustrated embodiment in more detail. On the actuating lever 2, the first contact bridge 31, which is now shown in detail, is held in a recess of the actuating lever 2. In the illustrated embodiment, the first contact bridge 31 is designed as a so-called H-bridge, wherein, when viewed from above, the contact bridge 31 resembles the letter "H" and has two parallel-running bridge arms 311, 312, which are connected by Figure 2 The transverse bridges 313 which are not visible in the figure are connected to each other. Reinforced contact points 314, 315, 316, 317 are arranged on the end sides of the bridge arms 311, 312, which strengthen the strength of the contact bridge 31 and make it more wear-resistant. In the embodiment shown here, the contact points 314-317 are designed as cylindrical shell-shaped reinforcement surfaces welded to the ends of the bridge arms 311, 312. Through the cylindrical shape extending transversely to the extension direction of the bridge arms 311, 312, linear contact surfaces through which current flows are formed between the fixed contacts 21, 22 (flat in this exemplary embodiment) and the contact points 314-317.

[0077] Compared to the prior art, the contact bridge 31 is not designed in the form of a contact carrier, i.e., in particular, is not designed to be rigid, but is designed as a concavely curved leaf spring, which is supported in the opening direction (i.e., when the closed electrical contacts between the contact points 314-317 and the fixed contacts 21, 22 are opened again) by a reinforcing device in the form of reinforcing arms 25, 26 arranged on the actuating rod 2. In the present exemplary embodiment, the reinforcing arms 25, 26 are integrally formed with the actuating rod 2 and are combined as described below. Figure 3 To be explained in more detail, the reinforcing arms 25 , 26 support the contact bridge 31 in the opening direction.

[0078] Figure 3 In the child Figure 3 a) to 3c) show in front views that when the contacts between the contact bridge 31 and the fixed contacts 21 , 22 are closed. Figure 2 Device in.

[0079] Figure 3 a) shows how the actuating lever 2 moves from a first switching position, in which the actuator 2 is moved to a second switching position (as in Figure 1In the second switching position, the first contact bridge 31 is in contact with the fixed contacts 21, 22. The movement direction of the actuating rod 2 is determined by Figure 3 In the first sub-figure, it can be clearly seen that the bridge arms 311, 312 extending on both sides of the actuating rod 2 (in this figure, the bridge arms 312 facing forward) abut against the reinforcing means in the form of reinforcing arms 25, 26. The shape of the first contact bridge 31 is such that the bridge arms 311, 312 first follow the contour of the reinforcing arms 25, 26 with a positive curvature, and then bend with a negative curvature in the direction of the horizontally extending fixed contacts 21, 22.

[0080] Figure 3 b) shows the point in time when the contact points 315-317 of the contact bridge 31 come into contact with the fixed contacts 21, 22. In principle, the movement of the actuating rod 2 can be stopped at this point in time, because at this point in time there is contact between the fixed contacts 21, 22 and the contact points 314-317, and thus a conductive path is established between the first fixed contact 21 and the second fixed contact 22. However, in order to further improve the reliability of the snap-action switch according to the present application, the contact portion formed by the contact points 314-317 and the fixed contacts 21, 22 is designed to be self-cleaning, which means that particles, deposits or deposits caused by material burnout located on the fixed contacts 21, 22 or the contact points 314-317 are mechanically loosened and pushed away. In the present exemplary embodiment, this is achieved by removing the contact points 314-317 from the fixed contacts 21, 22. Figure 3 b) The situation shown starts with further moving the actuating rod 2 in the direction shown, Figure 3 In the case shown in b), there is already contact between the contact points 314-317 and the fixed contacts 21, 22, whereby the spring-elastic contact bridge 31 is slightly bent, resulting in a lateral movement between the fixed contacts 21, 22 and the contact points 314-317. Through this lateral movement, the contact points 314-317 are guided along the fixed contacts 21, 22, so that the friction generated at the contact portion loosens the deposits and particles and pushes them outward. In this way, a continuously low contact resistance between the contact points 314-317 and the fixed contacts 21, 22 is ensured, thereby improving the reliability of the snap-action switch 100.

[0081] Furthermore, the contact bridges 31 , 32 formed from individual bridge arms 311 , 312 ensure that, when deposits and particles are present on one of the contact pieces, height compensation can be achieved (even between the individual bridge arms 311 , 312 for contacting the fixed contacts 21 , 22 ) due to the spring-elastic design of the contact bridge, thereby enabling more reliable closing of the electrical contacts.

[0082] Figure 4 a) to c) show Figure 3 The opening process of the contact bridge 31 in FIG.

[0083] Figure 4 a) shows Figure 3 After the contact bridge 31 in the Figure 3 c) is achieved. Figure 4 As indicated by the arrows in a) to c), the actuating rod 2 now moves downwards, i.e. away from the fixed contacts 21, 22, thereby again disconnecting the electrical connection between the fixed contacts 21, 22 and the contact points 314-317 of the contact bridge 31. In this case, it is assumed that the contact points 314-317 are welded to the fixed contacts 21, 22 due to the thermal load caused by the flowing current and therefore adhere to the fixed contacts 21, 22 and do not immediately release when the contact bridge 31 abuts against the reinforcing arms 25, 26.

[0084] Figure 4 b) shows the position of the actuating lever 2 in which the bridge arms 311, 312 of the contact bridge 31 rest against the reinforcing arms 25, 26 of the actuating lever 2, and then by further movement of the actuating lever 2 in the direction of the fixed contacts 21, 22, the contact points 314-317 are released from the fixed contacts 21, 22. By further movement of the actuating lever 2, the force in the direction of movement is transmitted to the contact bridge 31 via the reinforcing arms 25, 26. The reinforcing arms 25, 26 additionally reinforce and support the contact bridge 31 in this direction. In this way, in contrast to the spring-elastic design of the contact bridge 31, a greater opening force can be exerted on the welded contact part, so that it is reliably opened.

[0085] In this embodiment, the contact points 314 - 317 are pulled off from the fixed contacts 21 , 22 , ie, a pulling force acts in the contact bridge 31 .

[0086] Figure 5 a) and 5b) show the closure ( Figure 5 a)) and open ( Figure 5 b) is an alternative embodiment of the contact bridge 31 .

[0087] exist Figure 5 In the exemplary embodiment shown, the contact bridge 31 has a convex design overall, wherein the reinforcing arms 25, 26 arranged on the actuating lever 2 are also correspondingly configured to be inclined downward. The fixed contacts 21, 22 are also configured to be inclined relative to the horizontal plane according to the inclination of the contact bridge 31 in the region of the contact points 314-317, so that Figure 5 a), in the case of contact between the contact points 314-317 and the fixed contacts 21, 22, the self-cleaning will not occur as in accordance with Figure 3 The particles are pushed away as in the embodiment of FIG. 1 , but due to the change in the contact situation, the lateral movement between the contact points 314 - 317 and the fixed contacts 21 , 22 is a pulling movement directed toward the actuating rod 2 .

[0088] Depending on the contact situation, e.g. Figure 5 As shown in b), the contact points 314-317 are pushed away from the fixed contacts 21, 22 when opening, that is, the pressure separating the contact points 314-317 from the fixed contacts 21, 22 acts in the contact bridge.

[0089] and Figure 2-Figure 4 Compared to the embodiment shown in FIG. 314 - 317 , in FIG. Figure 5 In the embodiment of FIG. 3 , the contact points 314 - 317 are designed as flat contacts, while the fixed contacts 21 , 22 are designed as cylindrical contacts.

[0090] Figure 6 A further embodiment of a contact bridge 31 is shown in more detail, which can also be used according to Figure 1 device.

[0091] Figure 6 The contact bridge 31 shown is designed as an H-bridge having a first bridge arm 311 and a second bridge arm 312. The bridge arms 311, 312 are connected to one another in the center via a crosspiece 313 and each bridge arm 311, 312 is divided into two bridge arm parts 311a, 311b, 312a, 312b extending from the crosspiece 313.

[0092] In the present exemplary embodiment, the cross piece 313 is arranged in the center, so that the bridge arm parts 311a, 311b, 312a, 312b extend symmetrically from the cross piece 313 at right angles thereto. Figure 2 As described in the exemplary embodiment, the bridge arms 311, 312 are designed to extend first with a positive curvature and then with a negative curvature, so that the contact bridge 31 is designed to be concave in the central area and convex in the end areas of the bridge arms 311, 312. The contact points 314-317 are arranged on the end sides of the bridge arms 311, 312, wherein in this exemplary embodiment, the contact points 314-317 are designed as contact rivets. Compared with welded contacts, the advantage of contact rivets is that they can be produced using other manufacturing methods. This means that other material combinations are also possible. As the name "contact rivets" implies, the contact points 314-317 are attached to the corresponding bridge arm ends by rivets.

[0093] In the exemplary embodiment, the cross piece 313 is designed to extend linearly between the bridge arms 311, 312 and to be semicircular on both sides of the bridge arms 311, 312. This configuration can be used to align and center the contact bridge 31 in the actuating lever 2 and is therefore an assembly aid. Figure 7 A further exemplary embodiment of a contact bridge 31 is shown, wherein Figure 7 The contact bridge 31 shown has a completely convex profile. Figure 5As shown, the convex profile of the contact bridge 31 requires changes in the contact geometry and the self-cleaning behavior. Figure 7 In the exemplary embodiment of FIG. 5 , the contact points 314 - 317 are also designed as contact rivets.

[0094] Figure 8 a) and Figure 8 b) shows Figure 6 A modified embodiment of the contact bridge 31 in FIG.

[0095] and Figure 6 The embodiment of the contact bridge 31 shown is different. In this embodiment, the two bridge arms 311 and 312 are respectively designed to extend in parallel. Figure 8 The contact bridge 31 of a) is designed so that one bridge arm is in the leading position and the other bridge arm is in the trailing position.

[0096] In this context, "leading" means that when moving in the closing direction, the contact point arranged on the leading bridge arm contacts the assigned fixed contact before the trailing contact point in time, thereby establishing a conductive connection before the trailing contact point. Conversely, when opening the switch position, the trailing bridge arm or the contact point assigned to it is the first to break away from the corresponding fixed contact, while the leading bridge arm in the closing direction is the second to break the connection.

[0097] exist Figure 8 In the exemplary embodiment shown, the first bridge arm 311 and thus the contact points 314, 316 assigned thereto are configured as leading, while the second bridge arm 312 with the assigned contact points 315, 317 is configured as trailing. As a result of this embodiment, when the contacts are opened, the increased current density and the associated flashover and the resulting burnout substantially affect the contact points of the leading first bridge arm 311. By selecting suitable materials, for example, the leading bridge arm can be equipped with contact points made of a material that is more resistant to burnout, while the contact points of the trailing bridge arm can be provided with a material that is very conductive but has significantly more burnout due to flashover and is therefore provided with a more sensitive material.

[0098] Figure 8 b) shows Figure 8 a) is a partially enlarged view, which clearly shows how the leading bridge arm and the trailing bridge arm can be implemented. In this exemplary embodiment, the bridge arm is bent so that the first bridge arm portion 311b shown here is higher than the second bridge arm portion 312b by a height Δh in the closing direction, so that it is in the leading position in the closing direction.

[0099] In an alternative embodiment, the contact rivets used in each case can also have different heights, so that the bridge arms are bent in the same way, but the contact rivets for the leading contact point in each case have a greater height than the contact rivets for the trailing contact point. This embodiment can provide the leading contact point with a greater material thickness, which thus has an additional material thickness that can be worn away in addition to the material that is more resistant to burning.

[0100] Reference numerals list 1 Housing 2 Actuating lever 3 Actuating element 4 Compression spring 5 First forced opening lever 6 Second forced opening lever 8 First snap-action spring 9 Second snap-action spring 11, 12 Accommodating notches 13, 14 Spacers 15 Upper contact arm 16 Lower contact arm 17 First point of contact 18 Second contact point 19 Third contact point 20 Fourth contact point 21 First fixed contact 22 Second fixed contact 23 Third fixed contact 24 Fourth fixed contact 25, 26 reinforcement arm 31 First contact bridge 32 Second contact bridge 100 Snap Action Switches 311 First Bridge Arm 312 Second bridge arm 313 Transverse splice

Claims

1. A snap-action switch (100), comprising a housing (1) and an actuating rod (2) having two switching positions, the actuating rod having at least one contact bridge (31, 32) for electrically connecting at least one first contact pair (23, 24) in the switching position and a snap-action spring (8, 9) supported in a pre-tensioned manner substantially symmetrically on an actuating element (3) and the actuating rod (2), the action line of the snap-action spring being movable by the actuating element (3) so that the actuating rod (2) can be quickly switched from a first switching position in which the actuating rod (2) is substantially in a rest position to a second switching position in which the actuating rod (2) is substantially in an actuated position, wherein: The snap-action switch (100) further comprises a forced opening device, and when the forced opening force is exceeded, the forced opening device forces the actuating element (3) to switch at least from the first switch position to the second switch position. It is characterized in that The at least one contact bridge (31, 32) has at least two contact points (17, 18, 19, 20) at one end and at the other end for electrically contacting the first contact pair (23, 24) in parallel, wherein each of the contact points (17, 18, 19, 20) is designed to fully switch the rated electrical power of the snap-action switch (100).

2. The snap-action switch (100) according to claim 1, It is characterized in that The snap-action switch has two contact bridges (31, 32) for electrically connecting at least the first contact pair (23, 24) and at least one second contact pair (21, 22), wherein the contact points of the second contact bridge are also designed to fully switch the rated electrical power of the snap-action switch (100).

3. The snap-action switch (100) according to claim 2, It is characterized in that In the first switch position, the first contact pair is connected, and in the second switch position, the second contact pair (21, 22) is connected.

4. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that Each of the contact bridges (31, 32) is formed integrally.

5. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that The contact bridges (31, 32) are designed in the form of double H bridges, each of which has two bridge arms (311, 312) on both sides of the actuating rod (2) and at least one cross piece (313).

6. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that The contact bridges (31, 32) are designed such that, on both sides of the actuating rod (2), one bridge arm (311) is designed to be in the leading position, while the other bridge arm (312) is designed to be in the trailing position.

7. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that The contact bridges (31, 32) are designed to be spring-elastic.

8. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that The design of the contact bridges (31, 32), the arrangement of the contact points (17, 18, 19, 20) and the arrangement of the contact points relative to the contact pairs (21, 22, 23, 24) result in the contacts being self-cleaning.

9. The snap-action switch (100) according to claim 8, It is characterized in that The contact points (17, 18, 19, 20) and the contact pairs are designed and arranged relative to one another in such a way that, at least when the contacts are closed, a lateral movement occurs between the contact points (17, 18, 19, 20) and the contact pairs.

10. The snap-action switch (100) according to any one of the preceding claims, It is characterized in that At least two of the contact bridges (31, 32) are each assigned a reinforcement device in the opening direction.

11. The snap-action switch (100) according to claim 10, It is characterized in that The reinforcing device (25, 26) is arranged on the actuating rod (2).

12. The snap-action switch (100) according to claim 810 or 11, It is characterized in that The reinforcing device is formed integrally with the actuating rod (2).

13. The snap-action switch (100) according to any one of claims 8 to 10, It is characterized in that The reinforcement device is designed as a molded part extending from the actuating rod (2) in the extension direction of the contact bridges (31, 32), the molded part being in particular in the form of reinforcement arms (25, 26).

14. The snap-action switch (100) according to claim 13, It is characterized in that At least in the contact state, the molded part supports at least 1 / 5 of the bridge arm, preferably at least 1 / 4 of the bridge arm, more preferably at least half of the bridge arm, particularly preferably 3 / 4 of the bridge arm.

15. The snap-action switch (100) according to claim 13 or 14, It is characterized in that The molded part is designed in such a way that the contact bridge is prestressed.

16. The snap-action switch (100) according to any one of claims 13 to 15, It is characterized in that The molding is dimensioned so as to be able to transmit an opening force of at least 10N to the bridge arms (311, 312), preferably at least 20N, more preferably at least 30N.

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