Snap-action switch

Abstract

The present invention relates to a snap-action switch (100) comprising a housing (1), an actuation plunger (2) with two switching positions and with at least one contact bridge (31, 32) for electrically connecting at least one first pair of fixed contacts (23, 24) in a switching position and with snap-action springs (8, 9), which are preloaded and are supported substantially symmetrically on an actuation element (3) and the actuation plunger (2) and which have lines of action that can be shifted by the actuation element (3) in such a way that the actuation plunger (2) can be snapped from a first switching position, in which the actuation plunger (2) is substantially in a resting position, into a second switching position, in which the actuation plunger (2) is substantially in the actuation position, wherein the snap-action switch (100) also has a forced-opening assembly with which a switching at least from the first into the second switching position is imposed on the actuation element (3) when a forced-opening force is exceeded, wherein the at least one contact bridge (31, 32) has two respective contact points (17, 18, 19, 20) at one end and the other end for the electrically parallel contacting of the first pair of fixed contacts (23, 24), wherein each of the contact points (17, 18, 19, 20) is designed in such a way as to entirely switch an electrical rated power of the snap-action switch (100), and the actuation plunger (2), at least in the first direction of closing of the first pair of fixed contacts (23, 24), has at least one first stop (41) (where in Figure 3), which interacts with a first counter-stop (51) to limit a movement of the actuation plunger (2) in the direction of closing of the first pair of fixed contacts (23, 24).

Description

[0001] Snap switch

[0002] The present invention relates to a snap switch according to the preamble of claim 1.

[0003] Snap-action switches are generally known from the prior art and typically comprise a housing and a contact bridge having two switching positions that can be switched via an actuating plunger for electrically connecting fixed contacts, in particular at least a first pair of fixed contacts in the first switching position and at least a second pair of fixed contacts in the second switching position. Two snap springs are supported essentially symmetrically under pretension on an actuating element and the actuating plunger, the lines of action of which can be displaced by the actuating element such that the actuating plunger can be snapped from the first switching position, in which the actuating plunger is essentially in the rest position, to the second switching position, in which the actuating plunger is essentially in the actuated position.

[0004] Snap-action switches have in common that they operate with 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 arcing and thus damage to the contact elements. To provide this function, it is irrelevant whether the spring arms are formed integrally with the contact bridge or designed as separate components.

[0005] A snap switch known from the prior art is shown in Figure 9.

[0006] The snap-action switch shown has a housing 1 with a rectangular cross-section, which serves to accommodate the individual components of the snap-action switch. An actuating plunger 2 is arranged centrally in the housing 1. The actuating plunger 2 has a stop step inside the housing 1, which, when the actuating plunger 2 is in its rest position, rests against the inside of a wall of the housing 1. The actuating plunger 2 is pressed upwards into its rest position by a compression spring 4, so that the stop step 3 comes into secure contact. The actuating plunger 2 is guided in a sleeve-like receptacle in the area of ​​the compression spring 4 and, at an end opposite the compression spring 4, in a recess in the housing 1.

[0007] Approximately at the level of half of a longitudinal extension of the actuating plunger 2 located within the housing 1, the plunger has two diametrically opposed, i.e., in the present embodiment, mirror-image, receiving notches 7, each of which is designed to support a V-shaped snap spring 8, 9 on one side. A contact carrier 10 is held under prestress on the actuating plunger 2 by means of the snap springs 8, 9.

[0008] The other end of the snap springs 8, 9 is each received in a receiving notch 11, 12 of an insulating spacer 13, 14. The spacers 13, 14 hold an upper contact arm 15 and a lower contact arm 16 parallel to each other and spaced apart from each other. The contact arms 15, 16 are approximately O-shaped when viewed from above. They are held in place by the snap springs 8, 9 being arranged under pretension between the actuating plunger 2 and the spacers 13, 14, so that the spacers 13, 14 are pressed against the contact arms 15, 16, thus securing them in their position.

[0009] The contact arms 15, 16 have contact points 17, 18, 19, 20 arranged at the ends, wherein the contact points 17, 18, 19, 20 arranged on the contact arms 15, 16 are each assigned opposite fixed contacts 21, 22, 23, 24, so that in each case one contact arm 15, 16 in the actuating position and the other contact arm 16, 15 in the rest position of the snap switch contacts the fixed contacts 21, 22, 23, 24 assigned to it and connects them to one another in an electrically conductive manner.

[0010] A first fixed contact 21 is assigned to a first contact point 17, and a second fixed contact 22 is assigned to a second contact point 18. The first fixed contact 21 and the second fixed contact 22 are thus electrically connected to one another by the upper contact bridge 15 and form a first contact pair. Similarly, a third fixed contact 23 is assigned to a third contact point 19, and a fourth fixed contact 24 is assigned to a fourth contact point 20, so that the third fixed contact 23 and the fourth fixed contact 24 are electrically connected to one another by the lower contact bridge 16 and form a second contact pair.

[0011] Since thermal overload of the contact points can lead to unwanted welding of the contact arms to the contacts of the contact pairs, i.e., the fixed contacts, in such snap-action switches, lever elements are provided for positive opening in some applications. Appendix K of the DIN EN 60947-5-1 standard specifies such a rigid, positive opening mechanism in addition to the snap-action spring mechanism for standard snap-action switches. This ensures that, for safety reasons, the normally closed contact position is reliably opened when the actuating element of the snap-action switch is actuated. This positive opening mechanism is capable of opening contact points welded together by excess current by applying appropriate force.These lever elements are usually pivotable over the switching plunger and can be placed at one end against the contact carrier or contact arms. When sufficient force is applied to the switching plunger, they force the contact points away from the fixed contacts, thus forcing the switching position to open. To configure one of the switching positions as the rest position, an additional spring element can be integrated into the snap-action switch, as shown in the example in Figure 9, so that the position of the contact carrier in the rest position is stabilized by the force of the spring element.

[0012] The familiar snap-action switches are already very reliable and can be used for safety-critical applications. However, it is considered a disadvantage that they can fail electrically due to various effects, i.e., the contact arms fail to establish a conductive connection between the fixed contacts or only do so inadequately. Reasons for such failure can include excessive contact resistance due to deposits of dirt or burn-off on the contacts, breakage of the snap springs or the contact bridge due to mechanical and / or thermal stress.

[0013] One reason for this degradation of contact points 17 - 19 is the so-called bouncing of the contact bridge when it is transferred from one switching position to the other. Bounce in this context describes a mechanically triggered disturbance effect when the snap switch is switched. Instead of an immediate and continuous electrical contact, the high-speed switching of the contact bridge and the impact of the contact bridge on the fixed contacts briefly causes the electrical connection to close and open multiple times. The reason for this is an elastic rebound of the contact bridge from the fixed contacts. This repeated closing and opening of the electrical connection causes an electric arc at voltages above 16 V and up to several hundred amperes, which acts on contact points 17 - 20 at temperatures of 10,000 °C to 15,000 °C and thus causes increased burn-off.The burn-off results in corresponding contamination of the contact points and thus in increased contact resistance and a reduced service life of the contact points 17 - 20.

[0014] It is therefore the object of the present invention to improve a known snap-action switch in such a way that it has an increased service life and an increased availability or increased reliability when contacting the contact points with the fixed contacts.

[0015] This object is achieved by a snap-action switch having the features of patent claim 1. Advantageous further developments are the subject of dependent claims and the following description.

[0016] A snap-action switch according to the invention comprises a housing, an actuating plunger having two switching positions with at least one contact bridge for electrically connecting at least a first pair of fixed contacts in a switching position, and snap-action springs supported substantially symmetrically under prestress on an actuating element and the actuating plunger, the lines of action of which are displaceable by the actuating element such that the actuating plunger can be snapped from a first switching position, in which the actuating plunger is substantially in the rest position, to a second switching position, in which the actuating plunger is substantially in the actuated position, wherein the snap-action switch further comprises a positive opening arrangement, by means of which a switching at least from the first to the second switching position is forced upon exceeding a positive opening force on the actuating element,wherein the actuating plunger has at least one first stop, at least in the closing direction of the first pair of fixed contacts, which, in cooperation with a first counter-stop, limits a movement of the actuating plunger in the closing direction of the first pair of fixed contacts.

[0017] The first stop and the first counter-stop create an arrangement in which the movement of the actuating plunger is decelerated not only by the contact bridge, but also by the stop. The material and structure of the first stop and / or the first counter-stop absorbs kinetic energy from the movement of the actuating plunger and dissipates it via the housing. By absorbing and dissipating this energy, the kinetic energy of the actuating plunger is reduced and not transferred back to it. This ensures that the actuating plunger and the contact bridges arranged on it bounce less, which increases the overall service life of the contact points and the contact bridges, and thus of the snap-action switch as a whole.

[0018] Reducing bounce increases the service life of the contact points, as they close and reopen less frequently, thus creating fewer arcs and reducing contact point wear. The impact and reduction in bounce also increases the service life of the contact bridge, as the contact bridge is bent less severely when the stop contacts the counter-stop, and fewer bounces reduce the number of alternating bending loads acting on the contact bridge.

[0019] The constantly reversing stress conditions in the rhythm of the alternating bending loads, in particular the respective tensile stresses, can lead to notches and cracks on the surfaces of the contact bridge, which ultimately lead to the component breaking during the alternating bending load. The time of break depends on the one hand on the magnitude of the bending force and the resulting extent of the alternating elastic deflection of the component, and on the other hand on the number of consecutive alternating loads. By reducing the bouncing of the contact bridge, the stability of the contact bridge is increased by the same amount. For example, the number of bouncing events can be reduced from 5 to 2, preferably to 1 and ideally to 0, so that the stability increases by the same amount, i.e. it is tripled, quadrupled or quintupled.

[0020] Because part of the kinetic energy of the actuating plunger is absorbed and partially dissipated by the stop, it is possible to make the contact bridge less massive than with the state of the art, thus reducing its mass. The lower mass of the contact bridge also reduces bounce.

[0021] The snap switch can be designed as an opener or a closer, whereby the rest position of the actuating plunger defines whether it is a normally closed contact, i.e. an opener, or a normally open contact and thus a closer.

[0022] In an advantageous embodiment, the snap-action switch has two contact bridges for electrically connecting at least the first pair of fixed contacts and at least a second pair of fixed contacts, wherein the actuating plunger has a second stop in the closing direction of the second pair of fixed contacts, which, in cooperation with a second counter-stop, limits a movement of the actuating plunger in the closing direction of the second pair of fixed contacts.

[0023] By using two contact bridges with opposite closing directions, an arrangement is created in which when the electrical contact of the first pair of fixed contacts is opened, the electrical contact of the second pair of fixed contacts is closed, and vice versa. This makes it possible to switch two different electrical contacts, whereby when one contact is closed, the other contact is opened. If the snap-action switch is designed so that the first pair of fixed contacts is connected in the first switching position and the second pair of fixed contacts is connected in the second switching position, the snap-action switch is implemented as an opener or a makeer, depending on which fixed contacts are contacted from the outside.

[0024] By providing a stop in both closing directions, the bouncing of the actuating plunger is reduced in both directions, achieving the positive effects described above for both contact bridges. Two contact bridges with identical closing directions can be used to create a double break or double make contact. Similarly, two contact bridges per closing direction can create a double break and double make contact simultaneously.

[0025] In the context of the present disclosure, the term closing direction is to be understood as referring to the direction of movement of the actuating plunger in relation to a pair of fixed contacts in such a way that an electrical contact of the respective pair of fixed contacts is established by the contact bridge.

[0026] The term "contact point" should be understood to encompass not only point-like contacts, but also linear or surface-like contacts. It is obvious to those skilled in the art that a purely point-like contact is not possible, but always involves at least a small area.

[0027] Preferably, the at least one contact bridge has at least two contact points at one end and at the other end for electrically contacting the first pair of fixed contacts in parallel, wherein each of the contact points is designed to completely switch an electrical rated power of the snap switch.

[0028] This design creates electrical and mechanical redundancy, ensuring that the snap-action switch remains available even if up to two contact points fail. The contact bridge can be implemented using electrically and mechanically parallel electrical conductors. In this way, with two parallel electrical conductors, for example, the electrical or mechanical failure of one of the conductors—in this case, the failure of the two contact points assigned to that conductor—can be compensated.

[0029] In an advantageous embodiment, the snap-action switch comprises a housing, an actuating plunger having two switching positions with at least two contact bridges for electrically connecting at least a first pair of fixed contacts in the first switching position and at least a second pair of fixed contacts in the second switching position, and with snap-action springs supported substantially symmetrically under pretension on an actuating element and the actuating plunger, the lines of action of which are displaceable by the actuating element in such a way that the actuating plunger can be snapped from the first switching position, in which the actuating plunger is substantially in the rest position, into the second switching position, in which the actuating plunger is substantially in the actuated position, wherein the snap-action switch further comprises a positive opening arrangement,by means of which switching from the first to the second switching position is forced upon exceeding a positive opening force on the actuating element, is characterized in that the at least two contact bridges each have at least two contact points at one end and the other end for electrically parallel contacting of the first contact pair in the first switching position and the second contact pair in the second switching position, wherein each of the contact points is designed to completely switch a rated electrical power of the snap-action switch, wherein the actuating plunger has a stop both in the closing direction of the first pair of fixed contacts and in the closing direction of the second pair of fixed contacts and a counter-stop cooperating with the respective stop, which limits movement of the actuating plunger in the closing direction of the respective pair of fixed contacts.

[0030] Designing the contact bridges with at least two contact points each has the advantage of enabling electrically parallel contact between the fixed contacts. This compensates for the failure of one switching point per contact point per switching bridge. This means that a contact point at either end of the contact bridge can fail, for example, due to contamination, burn-off, or a mechanical defect, and the functionality of the snap-action switch is still maintained. This creates additional redundancy and increases switching reliability. The availability of the snap-action switch increases.

[0031] In a design with two contact points per bridge end, the following contacting options are possible with cross-connection of the contact bridge parts, i.e., if the contact bridge is designed so that all contact points are electrically connected to one another: Ideally, both contact points on both sides make contact. In the event of any failure of one of the contact points, either on the input side and / or the output side, a situation exists in which at least one contact point is functional.

[0032] The term "contact point" is used here only to distinguish between the different positions of the contacts. Contact points are therefore not necessarily point-shaped, but can also be linear or flat.

[0033] In this application, the term "contact pair" is also used. Contact pairs are always the contact points of the associated fixed contacts arranged at opposite ends of a switching bridge. These comprise at least two contact points, i.e., a pair, but can also comprise multiple contact points. Preferably, however, the fixed contacts at both ends of the contact bridge comprise an identical number of contact points.

[0034] In an advantageous development of the snap-action switch, the contact bridges are each formed as a single piece. "Single piece" in this context means that the contact bridges are made entirely of the same material, which provides both the energy transfer and the static load-bearing properties. In contrast to the prior art, the contact bridges are thus characterized by a simple structure. The material of the contact bridges is therefore preferably both conductive and load-bearing.

[0035] A metal or metal alloy with springy properties is particularly suitable for the design of the contact bridge. Spring steel, for example, can be used, although bronze, brass, nickel silver, or copper alloys are preferred due to their higher conductivity. A copper-beryllium alloy is particularly preferred because it combines particularly good electrical and thermal conductivity with mechanical properties. Copper-nickel-silicon alloys can also be used because of the good electrical and thermal conductivity achievable with these alloys, combined with good mechanical properties. This type of design ensures that the contact bridge is mechanically stable despite its small material cross-section and is sufficiently dimensioned for the currents to be switched.

[0036] The spring properties of the contact bridge can be selected and the contact bridge dimensioned in such a way that the movement of the actuating plunger is dampened even before the stop hits the counter-stop.

[0037] In a preferred embodiment, the contact bridges are designed in the form of a double H-bridge, each with an H-bridge with two bridge legs on either side of the actuating plunger and at least one transverse web.

[0038] The term H-bridge refers to the design of the contact bridge in the shape of an "H". This design provides two parallel contact paths for contacting the opposite fixed contacts, whereby at the same time a cross contact can be made from one leg of the H-bridge to the other leg of the H-bridge via the crossbar.

[0039] The H-bridge design also offers the advantage that the individual legs of the H-bridge can be designed to be flexible in the closing direction, allowing height compensation of the individual contact points at one end of the bridge. For example, the H-bridge can compensate for a height difference caused by a particle between the contact points at one end of the H-bridge.

[0040] The contact bridge can also be designed such that on either side of the actuating plunger, one bridge leg is designed to be leading and the other bridge leg to be lagging. With such a design, a contact bridge can be realized in which the contact point located on the leading bridge leg is primarily exposed to switching arcs and the associated burn-off.

[0041] In this context, "leading" means that the leading leg of the contact bridge, or the contact point located on the leading leg, comes into contact with the fixed contacts first in the closing direction of the contact bridge, establishing an electrically conductive connection. The lagging contact point only contacts the fixed contact once a conductive connection has already been established via the leading leg.

[0042] Conversely, when opening, this means that the lagging leg of the contact bridge first breaks the electrical connection, followed by the leading leg. This ensures that a switching arc is created exclusively at the leading contact point, and only the leading contact point is prone to welding to the fixed contact, as this contact switches higher currents than the lagging contact.

[0043] In a preferred embodiment, the material of the respective contact point can be adapted accordingly. In particular, the contact points on the leading legs can be designed to be more resistant to erosion. Suitable materials for the contact points of the leading leg include silver, gold, or silver or gold alloys.

[0044] Conversely, the trailing leg can have contact points made of a highly conductive but less resistant material, e.g. gold.

[0045] With mixed loads, the leading contact point switches the high currents and is loaded accordingly. The lagging contact point switches when the contact resistance of the leading contact point becomes too high at lower currents. The lagging contact can have a contact material more suitable for lower loads because it does not switch high loads.

[0046] In a further embodiment, the contact bridges are designed to be spring-elastic. This allows for compensation of manufacturing tolerances and reliable contact, for example, through height compensation of particles, to be achieved. Furthermore, a spring-elastic design of the contact bridges can assist in the opening of the snap-action switch. The metals and metal alloys already mentioned above for the design of the contact bridges are particularly suitable materials. A spring-elastic design of the contact bridges also ensures reliable contact between the contact points and the fixed contacts. The position of the switching positions of the actuating plunger is preferably coordinated with the dimensions of the contact bridges so that the stop is not in contact with the respective counter-stop when the actuating plunger is in the rest position.The contact bridge is dimensioned in terms of its geometric dimensions and spring constant so that in the rest position, a force acting through the contact bridge against the closing direction is greater than a force acting through the snap springs in the closing direction.

[0047] The rest position of the actuating plunger refers to the static position of the actuating plunger in a switching position. This means the stable position that occurs when the switching process is complete and a force equilibrium is established.

[0048] Reliable contacting can also be supported if the contact bridges are designed in such a way and the contact points are arranged in such a way, and arranged relative to the fixed contacts, that the contacts are self-cleaning.

[0049] Self-cleaning of the contacts can be achieved, for example, by designing and arranging the contact points and the fixed contacts relative to each other in such a way that a lateral movement is caused between the contact point and the fixed contact, at least when the contacts are closed.

[0050] Such a lateral movement removes and removes deposits caused by burn-off, for example, during the lateral movement, thus ensuring reliable contact at all times.

[0051] If, for example, the contact bridge is made of a spring-elastic material, then when an electrical connection already exists, ie when the contact points are already in contact with the fixed contacts, a further movement of the contact bridge in the closing direction can cause a lateral movement of the contact points and the fixed contacts relative to each other, whereby deposits are rubbed off and simultaneously pushed away from the contacts.

[0052] In one embodiment, a reinforcement arrangement can be assigned to the at least one contact bridge in the opening direction. This reinforcement arrangement allows the at least one contact bridge itself to be dimensioned more weakly while still maintaining sufficient stability. Such a reinforcement arrangement can be particularly useful in the opening direction, since welds caused by thermal stress may have to be removed in this direction. At the same time, if the reinforcement arrangement acts exclusively in the opening direction, it can ensure flexibility in the closing direction on the one hand, while also ensuring sufficient stability in the opening direction on the other.

[0053] Such a reinforcement arrangement can, for example, be arranged on the actuating plunger, in particular be formed integrally with the actuating plunger.

[0054] Alternatively, a multi-part design is also conceivable, in which the reinforcement arrangement is designed as a separate component.

[0055] By arranging the reinforcement arrangement, and in particular by forming the reinforcement arrangement in one piece with the actuating plunger, a particularly space-saving and, in particular, easily implemented realization can be achieved in terms of production technology.

[0056] The actuating plunger can, for example, be designed in such a way that the contact bridge is inserted as a component into a receptacle of the actuating plunger and is fixed therein by a second part of the actuating plunger.

[0057] The reinforcement arrangement can, for example, be designed as a molded portion extending from the actuating plunger in the direction of extension of the contact bridge. The molded portions and the receptacle are preferably configured such that the contact bridge is held prestressed counter to the closing direction when inserted into the actuating plunger. In a side view, the contact bridge is in contact with the actuating plunger and the molded portions in the inserted state, preferably at three points. A bearing with three supports achieves a statically determined situation and ensures that there is no static overdetermination of the bearing of the contact bridge. Furthermore, a defined prestress of the contact bridge can be achieved by three supports. The contact bridge preferably rests on the support arrangement on both sides of the actuating plunger and is prestressed within the actuating plunger by a third support.For this purpose, the supports formed by the support arrangement act on one side surface of the contact bridge and the support formed within the actuating plunger acts on an opposite side surface of the contact bridge.

[0058] Preloading the contact bridge offers various advantages. Manufacturing tolerances of the contact bridge can be compensated for without the need for rework, as the contact bridge is positioned in a defined position by the moldings. Furthermore, it is possible to apply a defined preload to the contact bridge, thus providing an immediate increase in force in the opening direction to open the contacts.

[0059] The moldings can be implemented particularly easily during the production of the actuating plunger, e.g. in plastic injection molding, and can be created in the necessary dimensions.

[0060] It is preferred if the supports formed by the molded-on portions are designed symmetrically to the actuating plunger and support the contact bridge in the uncontacted state at a distance of at least 1 / 5, preferably at least 1 / 4, more preferably at least half, particularly preferably at least 3 / 4 of a projection of the contact bridge onto a line extending perpendicular to a longitudinal axis of the actuating plunger and parallel to a longitudinal extension of the contact bridge.

[0061] To determine the distance, the contact bridge is projected perpendicularly onto a line that is perpendicular to the longitudinal axis of the actuating plunger and runs parallel to a longitudinal extension of the contact bridge.

[0062] The further outwards on the contact bridge the support is located, the shorter the portion of the contact bridge projecting beyond the support is, which can deform elastically when the contact is opened, and the greater the force that can be transmitted in the opening direction. It has proven useful to arrange the supports in the opening direction in a range between 3 / 4 and 4 / 5 of a distance perpendicular to a longitudinal axis of the actuating plunger, whereby the distance perpendicular to a longitudinal axis of the actuating plunger is determined and the end of the contact bridge is assumed to be the point at which the contact bridge rests on the fixed contact when in contact. The supports are preferably designed as linear supports. The bearings are preferably loose bearings.

[0063] An opening force acting on the actuating plunger is thus transmitted to the contact bridge closer to the contact points, while simultaneously reducing the contact bridge's free cantilever length. A force acting against the opening, e.g., due to welding of the contact point to the fixed contact, acts via a reduced lever arm, reducing the risk of the contact bridge bending.

[0064] To prevent the contact bridge from slipping relative to the actuating plunger, it can be secured in the holder by a fixed bearing. It has been found that securing it in place can be achieved particularly easily by molding on the contact bridge into correspondingly shaped recesses in the holder.

[0065] The contact bridge can be designed, in particular, as a stamped and bent part. Stamped and bent parts can be manufactured cost-effectively and with high quality.

[0066] Alternatively, other manufacturing methods can be used, especially for smaller quantities. For example, various cutting processes, such as using a waterjet or laser, can be used, followed by a bending step.

[0067] In order to reliably transmit a prescribed opening force for positive opening of the rest position, the support arrangement is dimensioned such that an opening force of at least 10 N, preferably 20 N, more preferably 30 N can be transmitted to the contact points of the contact bridge. In this way, it can be ensured that the snap-action switches according to the present application also comply with the standard DIN EN 60947-5-1. However, the molded-on features also make it possible to transmit higher positive opening forces than the 20 N required by the standard, so that in particular a transmission of 30 N and more can be achieved. The actuating plunger can, for example, be designed in at least two parts such that the contact bridge can be inserted between two parts of the actuating plunger and thus fixed.

[0068] In an alternative design, the contact bridge is overmolded with the actuating plunger. This design has the advantage of being particularly cost-effective, reducing the number of components of the snap-action switch, and providing particularly good fastening of the contact bridge, as the contact bridge is fixed in the area of ​​the actuating plunger with a positive and non-positive fit.

[0069] In one embodiment, a first distance between a contact point and an associated fixed contact is smaller than a second distance between the stop and the associated counter-stop. This means that the contact points and the fixed contacts already establish electrical contact during the closing process, before the stop comes into contact with the counter-stop. The fact that the actuating plunger essentially breaks through during closing ensures self-cleaning of the contacts, as the additional axial movement of the actuating plunger causes a lateral movement of the contact points of the contact bridge.

[0070] It has been shown that a difference between the first and second distances, for example, between 0.1 mm and 0.3 mm, achieves particularly good results in terms of the cleaning effect and the reduction of contact point bounce. Because the actuating plunger initially penetrates and rebounds off the counter-stop, the contact bridge can compensate for part of the distance traveled during the rebound thanks to its resilient properties. This means that the bounce is reduced not only by dissipating the kinetic energy, but also because the contact bridge compensates for part of the movement during the counter-movement of the plunger through elastic rebound.

[0071] By optimizing the design, the number of bounces can be drastically reduced, thus maximizing the service life of the snap-action switch. In a preferred embodiment, the snap springs for actuating the actuating plunger, a spring force of the contact bridge, and the differential travel are coordinated to minimize the number of bounces, particularly to 1 or zero.

[0072] In the case of point switches designed as snap-action switches, the number of bouncers can be reduced to one or two due to the larger snap springs compared to other snap-action switches. A further reduction is currently not possible due to the significantly increased kinetic energy required when switching the actuating plunger due to the stronger snap springs.

[0073] All contacts, both on the contact bridge and the fixed contacts, can be cylindrical, flat, or spherical / oval (contact rivet). The contact surface of spherical contacts is point-shaped, cylindrical contacts are linear, and double-surface contacts are flat.

[0074] The phrase "two elements are associated with one another" is used in the present application for elements that interact with one another, in particular that interact electrically or mechanically. In this sense, two elements that establish an electrical connection through mechanical contact are associated with one another. For example, these can be a contact point and a fixed contact that make electrical contact with one another when the actuating plunger is in a switching position. Likewise, two mechanical elements that interact mechanically, for example, that meet or support one another, are associated with one another. For example, these can be a stop and the counter-stop that is arranged such that the stop hits when the actuating plunger is switched from one switching position to the other. Likewise, a reinforcement arrangement is associated with the contact arm of the contact bridge, for which this reinforcement arrangement forms a support.

[0075] The self-cleaning of the switching points can be designed as a pushing or pulling action. Depending on the angle at which the contact points and the fixed contacts meet, a pushing or pulling relative movement is performed between the contacts. Further details can be found in the exemplary embodiments described below. Advantageous embodiments and variants of the invention can be found in the subclaims and the following description. The features listed individually in the subclaims can be combined with each other in any technically expedient manner, as well as with the features explained in more detail in the following description, and represent other advantageous embodiments of the invention.

[0076] The present invention will be explained in detail below using exemplary embodiments with reference to the accompanying figures. They show:

[0077] Figure 1 shows a first embodiment of a snap switch according to the present application in a simplified representation,

[0078] Figure 2 shows a schematic diagram of the actuating plunger with the first

[0079] Contact bridge and associated fixed contacts,

[0080] Figures 3a) to d) show a closing process of a contact bridge of the snap switch according to Figure 2,

[0081] Figures 4a) to c) show an opening process of the contact bridge from Figure 3,

[0082] Figure 5 shows an embodiment of an actuating plunger as shown in Figures 3 and 4, in a sectional view,

[0083] Figure 6 shows a third embodiment of a contact bridge,

[0084] Figure 7 shows a fourth embodiment of a contact bridge,

[0085] Figures 8a) and 8b show a contact bridge with a leading and a trailing bridge leg and

[0086] Figure 9 shows a snap switch according to the prior art

[0087] (already discussed). In the figures, unless otherwise indicated, identical reference numerals designate identical or corresponding components with the same function.

[0088] Figure 1 shows a first embodiment of a snap switch 100 according to the present application.

[0089] The snap-action switch 100 is simplified in the illustration shown and shown with the housing 1 open, so that the functionality of the components located in the snap-action switch 100 is more clearly visible. The essential function of the snap-action switch 100 is accomplished by an actuating plunger 2 having at least two switching positions, wherein the actuating plunger 2 can be switched by means of an actuating element 3 between a first switching position, as shown in Figure 1, and a second switching position, in which the actuating plunger 2 is in a position displaced relative to the first switching position in the direction of the actuating element 3.The switching element 3 is connected to the actuating plunger 2 via two snap springs 8, 9 supported in parallel on the switching element 3 and the actuating plunger 2, so that actuation of the actuating element 3 shifts the characteristics of the snap springs 8, 9 such that the actuating plunger 2 is snapped from the first switching position to the second switching position. In the present embodiment, the actuating element 3 is further actuated by a compression spring 4, so that the first switching position shown in Figure 1 is stabilized by the compression spring 4.

[0090] The snap-action switch 100 shown in Figure 1 further comprises a positive opening arrangement consisting of a first positive opening lever 5 and a second positive opening lever 6. The positive opening levers 5, 6 are supported at one end on a circumferential collar of the actuating plunger 2 and at the other end are slidably mounted in the housing 1 of the snap-action switch 100. If a predetermined actuating force is applied via the actuating element 3, this comes into contact with the positive opening levers 5, 6 and, by tilting the positive opening levers 5, 6, effects an indirect mechanical coupling of the actuating element 3 via the positive opening levers 5, 6 to the actuating plunger 2, so that, in the event that a snap-action switchover of the actuating plunger 2 from the first switching position to the second switching position could not be effected, a mechanically forced switchover occurs.As already explained with reference to the prior art, such a positive opening may be necessary if, for example, due to thermal stress, contacts of the snap-action switch 100 are welded together in a switching position (in this case the first switching position) and as a result the snap-action springs 8, 9 are not able to release the contacts and switch the switching position.

[0091] In the snap-action switch 100 shown in Figure 1, a first contact bridge 31 and a second contact bridge 32 are arranged on the actuating plunger 2. In the first switching position of the actuating plunger 2 shown in Figure 1, the first contact bridge 31 is not in contact with its associated fixed contacts 21, 22, and the second contact bridge 32 electrically connects a third fixed contact 23 and a fourth fixed contact 24. To contact the respective fixed contacts 21, 22, 23, 24, the contact bridges 31, 32 have contact points 17, 18, 19, 20 arranged on their ends, which reinforce the contact bridges 31, 32 and thus make them wear-resistant.

[0092] Reinforcing arms 25, 26 are integrally formed on the actuating plunger 2 to support the contact bridge 31, 32 in the opening direction. The reinforcing arms 25, 26 extend away from the actuating plunger 2 on both sides. On a side facing the contact bridge 31, 32, the reinforcing arms 25, 26 have a pitch selected such that the contact bridge 31, 32 only rests against the reinforcing arms 25, 26 at the ends. A side of the reinforcing arms 25, 26 facing away from the contact bridge 31, 32 is oriented perpendicular to a longitudinal axis and direction of movement of the actuating plunger 2 and, in the present embodiment, serves as a stop 41, 42 to limit movement of the actuating plunger 2 in the closing direction.

[0093] By designing the stop 41, 42, the closing movement of the actuating plunger 2 is limited in the closing direction by abutting a counter-stop 51, 52 formed in the housing 1. By abutting the stop 41, 42 against the counter-stop 51, 52, part of the kinetic energy of the actuating plunger 2 is absorbed, thus reducing bouncing of the actuating plunger 2 itself. It is clear from Figure 1 that a first distance sl between the contact points 17, 18, 19, 20 on the contact bridge 31, 32 and the respectively associated fixed contacts 21, 22, 23, 24 is smaller than a second distance s2 between the stop 41, 42 and the respectively associated counter-stop 51, 52. This configuration has the consequence that an electrical contact is already established before the stop 41, 42 meets the counter-stop 51, 52.This ensures, on the one hand, that part of the kinetic energy is absorbed by the spring-loaded contact bridges 31, 32 before the stop 41, 42 hits the counter-stop 51, 52 and, on the other hand, that the actuating plunger 2 moves even further in the closing direction after the contact points 17, 18, 19, 20 hit the fixed contacts 21, 22, 23, 24, the contact points 17, 18, 19, 20 execute a lateral movement relative to the fixed contacts 21, 22, 23, 24, which causes the contact points to self-clean.

[0094] The stop 41, 42 also reduces the mechanical load on the contact bridges 31, 32, since the kinetic energy of the actuating plunger 2 does not have to be absorbed exclusively by the contact bridges 31, 32, but is essentially dissipated by the impact of the stop 41, 42 on the counter-stop 51, 52. This makes it possible to design the contact bridge 31, 32 with a less massive design compared to the prior art as shown in Figure 9, so that the mass of the contact bridge 31, 32 can be reduced. Because the contact bridge 31, 32 has a lower mass, bouncing is also reduced.

[0095] Because the contact bridge 31, 32 elastically compresses after the electrical contact between the contact points 17, 18, 19, 20 and the associated fixed contacts 21, 22, 23, 24 until the stop 41, 42 hits the counter-stop 51, 52 over the difference distance As between the first distance sl and the second distance s2, it is achieved that even if the actuating plunger 2 bounces back for the difference, the mechanical and electrical contact initially remains.

[0096] Figure 2 shows a schematic diagram of the actuating plunger 2 with the first contact bridge 31 and the associated fixed contacts 21, 22 in the second switching position. The explanations given in the following figures regarding the second pair of fixed contacts 21, 22 and the first contract bridge 31, as well as the associated first stop 41 and the first counter-stop 51, are exemplary and apply mutatis mutandis to the opposite direction of movement and the corresponding pair of fixed contacts 23, 24, the second contact bridge 32, as well as the second stop 42 and second counter-stop 52 formed in this direction of movement.

[0097] The illustration in Figure 2 is highly simplified and is essentially intended to explain the operating principle of the illustrated embodiments in more detail. The first contact bridge 31, now shown in detail, is held in a recess of the actuating plunger 2. In the illustrated embodiment, the first contact bridge 31 is designed as a so-called H-bridge, wherein the contact bridge 31 resembles the letter "H" in a top view and has two parallel bridge legs 311, 312, which are connected to one another by means of a crosspiece 313 (not visible in Figure 2). Reinforced contact points 314, 315, 316, 317 are arranged at the ends of the bridge legs 311, 312, which reinforce the contact bridge 31 and thus make it wear-resistant.In the present embodiment, the contact points 314-317 are designed as cylindrical shell-shaped reinforcing surfaces welded to the ends of the bridge legs 311, 312. The cylindrical shape extending transversely to the direction of extension of the bridge legs 311, 312 creates a linear contact surface between the fixed contacts 21, 22, which are flat in the present embodiment, and the contact points 314-317, over which electrical current flows.

[0098] The contact bridge 31 is designed as a concavely curved leaf spring which is supported in the opening direction, i.e. when an electrical contact closed between the contact points 314-317 and the fixed contacts 21, 22 is opened again, by a reinforcing arrangement in the form of reinforcing arms 25, 26 arranged on the actuating plunger 2. In the present exemplary embodiment, the reinforcing arms 25, 26 are formed as integral parts with the actuating plunger 2 and support the contact bridge 31 in the opening direction, as will be explained in more detail below in connection with Figure 3. In the present exemplary embodiment, the reinforcing arms 25, 26 are simultaneously designed as a first stop 41, with which the actuating plunger 2 strikes in the closing direction against a first counter-stop 51, which in the present case is identical to the fixed contacts 21, 22.The illustrated design is particularly easy to manufacture, since an additional counter-stop 51 does not need to be designed separately. At the same time, however, the fixed contacts 21, 22 must be significantly more solid so that they can dissipate the transmitted kinetic energy.

[0099] Figure 3 shows in the sub-figures 3a) to 3d) an arrangement similar to the arrangement in Figure 2 in a plan view from the front when closing the contact between the first contact bridge 31 and the first pair of fixed contacts 21, 22. The illustrated arrangement differs from the design of Figure 2 in that the first counter-stop 51 is formed separately from the fixed contacts 21, 22.

[0100] Figure 3a) shows how the actuating plunger 2 moves from the first switching position, in which - as shown in Figure 1 - the second contact bridge 32 contacts the fixed contacts 23, 24, to the second switching position in which contact is established between the first contact bridge 31 and the fixed contacts 21, 22. The direction of movement of the actuating plunger 2 is indicated by the arrow in Figure 3a). In the first partial figure, it can be clearly seen that the bridge legs 311, 312 extending on both sides of the actuating plunger 2 - in the present illustration this is the forward-facing bridge leg 312 - rest against the reinforcement arrangement in the form of the reinforcement arms 25, 26. The first contact bridge 31 is shaped such that the bridge legs 311, 312 rest only on the end of the reinforcement arms 25, 26.Because the first contact bridge 31 is designed such that it is only clamped centrally and rests on the end of the reinforcing arms 25, 26, a statically determined design with a defined prestress of the first contact bridge 31 is created.

[0101] Figure 3b) shows the point in time at which the contact points 315-317 of the first contact bridge 31 come into contact with the fixed contacts 21, 22. In principle, movement of the actuating plunger 2 could stop at this point in time, since at this point in time there is contact between the second pair of fixed contacts 21, 22 and the contact points 314-317, thus establishing an electrically conductive path between the first fixed contact 21 and the second fixed contact 22. However, to further increase the reliability of the snap-action switch according to the present application, the contact points formed by the contact points 314-317 and the fixed contacts 21, 22 are designed to be self-cleaning. This means that particles, deposits, or deposits caused by the burning of the materials 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 moving the actuating plunger 2 further in the direction shown, starting from the situation shown in Figure 3b), in which contact already exists between the contact points 314-317 and the fixed contacts 21, 22, whereby the spring-elastic contact bridge 31 is slightly bent open, resulting in a lateral movement between the fixed contacts 21, 22 and the contact points 314-317. This lateral movement guides the contact points 314-317 along the fixed contacts 21, 22, so that the friction generated at the contact points loosens deposits and particles and pushes them outwards. In this way, a permanently low contact resistance between the contact points 314-317 and the fixed contacts 21, 22 is ensured, thus increasing the reliability of the snap-action switch 100.

[0102] In addition, the contact bridges 31, 32 formed with individual bridge legs 311, 312 ensure that in the event of deposits and particles on one of the contact partners, height compensation can take place due to the spring-elastic design of the contact bridge - also between the individual legs 311, 312 for contacting a fixed contact 21, 22 - whereby an electrical contact is closed even more reliably.

[0103] In Figure 3d), the end of the movement of the actuating plunger 2 is indicated; in the position shown, the actuating plunger 2 has moved into a stable position due to the rebound from the first counter-stop 51 and due to the spring force of the first contact bridge 31 after reaching the first counter-stop 51, which position will only be left again by switching.

[0104] Figures 4a) to c) show an opening process of the first contact bridge 31 from Figure 3. Figure 4a) shows the situation reached in Figure 3d) after the first contact bridge 31 from Figure 3 has been completely closed. As indicated by the arrows in Figures 4a) to c), the actuating plunger 2 now moves downwards, i.e. away from the fixed contacts 21, 22, so that an electrical connection between the fixed contacts 21, 22 and the contact points 314-317 of the contact bridge 31 is released again. It is assumed here that the contact points 314-317 are welded to the fixed contacts 21, 22 due to thermal stress from the flowing currents and therefore adhere to them and do not detach immediately when the contact bridge 31 rests against the reinforcing arms 25, 26.

[0105] Figure 4b) shows the position of the actuating plunger 2 in which the bridge legs 311, 312 of the contact bridge 31 rest against the reinforcing arms 25, 26 of the actuating plunger 2 and then, by further movement of the actuating plunger 2 in the direction away from the fixed contacts 21, 22, the contact points 314-317 are released from the fixed contacts 21, 22. By further movement of the actuating plunger 2, the force in the direction of movement is introduced into the contact bridge 31 via the reinforcing arms 25, 26. The reinforcing arms 25, 26 additionally reinforce and stiffen the contact bridge 31 in this direction. In this way, as shown in Figure 4c), it is possible to apply an increased opening force to the welded contact point, contrary to the spring-elastic design of the contact bridge 31, so that it is reliably opened.

[0106] In this embodiment, the contact points 314-317 are deducted from the fixed contacts 21, 22, ie a tensile force acts in the contact bridge 31.

[0107] Figure 5 shows an alternative design of the actuating plunger 2 in a longitudinal section.

[0108] In the illustration shown in Figure 5, the prestressing of the first contact bridge 31 is realized by means of three supports 61, 62, 63. On the one hand, the first contact bridge 31 rests on the reinforcing arms 25, 26 extending on both sides of the actuating plunger 2, which form a first support 61 and a second support 62. The first support 61 and the second support 62 act on a surface of the first contact bridge 31 facing the reinforcing arms 25, 26 and located at the front in the closing direction. On the other hand, the first contact bridge 31 rests centrally on a third support 63, which acts on an opposite side of the first contact bridge 31 and prestresses the concavely curved first contact bridge 31.To achieve a defined prestressing and preloading of the first contact bridge 31, an abutment is arranged opposite the third support 63, so that the first contact bridge 31 is clamped between the third support 63 and the abutment in the position shown. The abutment ensures that the contact bridge 31 has a defined prestress in the desired position.

[0109] The second contact bridge 32 is arranged mirrored to the first contact bridge 31 on a mirror plane that is perpendicular to a direction of movement of the actuating plunger 2 and runs centrally through the actuating plunger 2, and is held and prestressed in the same way.

[0110] Contact rivets are arranged at the ends of the contact bridges 31, 32 of the embodiment shown in Figure 5, which serve to reinforce the contact points 17, 18, 19, 20 and make them more resistant to burn-off and mechanical stress.

[0111] Figure 6 shows in a more detailed representation a further embodiment of the contact bridge 31, as it can be used in an arrangement as in Figures 1 to 5.

[0112] The contact bridge 31 shown in Figure 6 is designed as an H-bridge with a first bridge leg 311 and a second bridge leg 312. The bridge legs 311, 312 are centrally connected to one another by the crosspiece 313 and are each divided into two bridge leg sections 311a, 311b, 312a, 312b extending from the crosspiece 313.

[0113] In the present embodiment, the crosspiece 313 is arranged centrally, so that the bridge leg sections 311a, 311b, 312a, 312b each extend symmetrically from the crosspiece 313 and at right angles to it. The bridge legs 311, 312 are initially designed with a positive curvature and then extend with a negative curvature, so that the contact bridge 31 is concave in a central region and convex in the end regions of the bridge legs 311, 312. The contact points 314-317 are arranged at the ends of the bridge legs 311, 312; in the present embodiment, these are designed as contact rivets. Compared to soldered contacts, contact rivets have the advantage that they can be produced using different manufacturing processes. This means that other material combinations are possible.As the name "contact rivets" suggests, the contact points 314-317 are attached to the respective bridge leg end with a rivet or are themselves designed as a rivet.

[0114] In the present embodiment, the crosspiece 313 is designed to extend linearly between the bridge legs 311, 312 with a semicircular shape on both sides of the bridge legs 311, 312. This shape can be used to align and center the contact bridge 31 within the actuating plunger 2 and thus represents an assembly aid.

[0115] Figure 7 shows a further embodiment of a contact bridge 31, wherein the contact bridge 31 shown in Figure 7 has a completely convex profile.

[0116] Figures 8a) and 8b) show a modified embodiment of the contact bridge 31 from Figure 6.

[0117] In contrast to the embodiment of the first contact bridge 31 shown in Figure 6, in which both bridge legs 311, 312 are designed to run parallel, the embodiment of the first contact bridge 31 according to Figure 8a) is designed such that one bridge leg 311 is designed to lead and the other bridge leg 312 is designed to lag.

[0118] In this context, "leading" means that the contact point 314, 316 arranged on the leading bridge leg 311 contacts the associated fixed contact during a movement in the closing direction before the contact point 315, 317 arranged on the trailing bridge leg, thus establishing an electrically conductive connection before the latter. Conversely, the trailing bridge leg 312 or its associated contact points 315, 317 are the first to lift off the associated fixed contact when the switch position is opened, and the bridge leg 311 leading in the closing direction is the second to break the connection.

[0119] In the embodiment shown in Figure 8, the first bridge leg 311 and thus also the contact points 314, 316 assigned to it are designed to be leading, and the second bridge leg 312 with the assigned contact points 315, 317 are designed to be lagging in the closing direction. Figure 8a) shows the entire contact bridge. This design has the consequence that when the contacts open, increased current densities and the associated arcing and the resulting erosion essentially affect the contact points 314, 316 of the leading, first bridge leg 311. By a suitable choice of material, the leading bridge leg 311 can thus, for example, be equipped with contact points made of a material more resistant to erosion, whereas the lagging bridge leg 312 can be provided with contact points 315, 317 made of a very well-conducting material, but with significantly more erosion and thus a more sensitive material to arcing.

[0120] Figure 8b) shows an enlarged detail from Figure 8a), which clearly shows how a leading and a trailing bridge leg 311 can be realized. In the present exemplary embodiment, the bridge legs 311, 312 are bent in such a way that the first bridge leg section 311b, shown here as an example, projects beyond the second bridge leg section 312b in the closing direction by a height Ah and is thus leading in the closing direction.

[0121] In an alternative embodiment, the contact rivets used could also have different heights, so that the bridge legs 311, 312 are bent equally, but the contact rivets used for the leading contact point 314, 316 have a greater height than the contact rivets for the trailing contact point 315, 317. Such a configuration can provide a greater material thickness for the leading contact point 314, 316, so that in addition to a material more resistant to burn-off, it also has an additional material thickness that can be worn away.

[0122] Housing

[0123] Actuating plunger Actuating element Compression spring First positive opening lever Second positive opening lever First snap spring Second snap spring , 12 Receiving notch , 14 Spacer Upper contact arm Lower contact arm First contact point Second contact point Third contact point Fourth contact point First fixed contact Second fixed contact Third fixed contact Fourth fixed contact , 26 Reinforcing arm First contact bridge Second contact bridge First stop Second stop First counter stop Second counter stop 61 First support

[0124] 62 second support

[0125] 63 third support

[0126] 100 snap switches

[0127] 311 first bridge leg

[0128] 311a, 311b bridge leg sections

[0129] 312 second bridge leg

[0130] 312a, 312b bridge leg sections

[0131] 313 Crossbar

[0132] 314-317 contact points

[0133] 324-327 contact points

[0134] Ah height sl first distance s2 second distance

[0135] AS differential section

Claims

Patent claims 1. Snap-action switch (100) with a housing (1), an actuating plunger (2) having two switching positions, with at least one contact bridge (31, 32) with contact points (314-317) arranged at one end and the other end on the contact bridge (31, 32) for electrically connecting at least a first pair of fixed contacts (23, 24) in a switching position, and with snap-action springs (8, 9) which are supported essentially symmetrically under pretension on an actuating element (3) and the actuating plunger (2), the lines of action of which are displaceable by the actuating element (3) in such a way that the actuating plunger (2) can be snapped over from a first switching position, in which the actuating plunger (2) is essentially in the rest position, into a second switching position, in which the actuating plunger (2) is essentially in the actuated position, wherein the snap-action switch (100) further comprises a positive opening arrangement (5, 6),by means of which a switching at least from the first to the second switching position is forced upon exceeding a positive opening force on the actuating element (3), characterized in that the actuating plunger (2) has at least one first stop (41) at least in the closing direction of the first pair of fixed contacts (23, 24), which, in cooperation with a first counter-stop (51), limits a movement of the actuating plunger (2) in the closing direction of the first pair of fixed contacts (23, 24).

2. Snap-action switch (100) according to claim 1, characterized in that the snap-action switch (100) has two contact bridges (31, 32) for electrically connecting at least the first pair of fixed contacts (23, 24) and at least a second pair of fixed contacts (21, 22), wherein in the first switching position the first pair of fixed contacts (23, 24) and in the second switching position the second pair of fixed contacts (21, 22) are connected and wherein the actuating plunger (2) has a second stop (42) in the closing direction of the second pair of fixed contacts (21, 22), which in cooperation with a second counter-stop (52) limits a movement of the actuating plunger (2) in the closing direction of the second pair of fixed contacts (21, 22).

3. Snap-action switch (100) according to one of the preceding claims, characterized in that the contact bridges (31, 32) are spring-elastic.

4. Snap-action switch (100) according to one of the preceding claims, characterized in that the contact bridges (31, 32) are designed in such a way and the contact points (17, 18, 19, 20) are arranged in such a way, and arranged relative to the fixed contacts (21, 22, 23, 24), that the contacts are self-cleaning.

5. Snap-action switch (100) according to claim 4, characterized in that the contact points (17, 18, 19, 20) and the fixed contacts (21, 22, 23, 24) are designed and arranged relative to one another in such a way that, at least when the contacts are closed, a lateral movement is brought about between the contact point (17, 18, 19, 20) and the fixed contact (21, 22, 23, 24).

6. Snap-action switch (100) according to one of the preceding claims, characterized in that a reinforcement arrangement (25, 26) is assigned to at least one of the contact bridges (31, 32) at least in the opening direction.

7. Snap-action switch (100) according to claim 6, characterized in that the reinforcement arrangement (25, 26) is arranged on the actuating plunger (2).

8. Snap-action switch (100) according to one of claims 6 or 7, characterized in that the reinforcement arrangement (25, 26) is integral with the actuating plunger (2) is trained.

9. Snap-action switch (100) according to one of claims 6 to 8, characterized in that the reinforcing arrangement (25, 26) is designed as a molded-on portion extending from the actuating plunger (2) in the direction of an extension direction of the contact bridge (31, 32), in particular in the form of reinforcing arms (25, 26).

10. Snap-action switch (100) according to claim 9, characterized in that the contact bridge (31, 32) is arranged in a receptacle of the actuating plunger (2) and the formed portions are designed such that the contact bridge (31, 32) is held in a prestressed manner.

11. Snap-action switch (100) according to claim 9 or 10, characterized in that the projections each form a support (61, 62) which supports the contact bridge (31, 32), at least in the contacted state, at a distance of at least 1 / 5, preferably at least 1 / 4, more preferably at least half, particularly preferably between 3 / 4 and 4 / 5 of a projection of the contact bridge (31, 32) onto a line extending perpendicular to a longitudinal axis of the actuating plunger (2) and parallel to a longitudinal extent of the contact bridge (31, 32).

12. Snap-action switch (100) according to one of claims 7 to 11, characterized in that the reinforcement arrangement (25, 26) is dimensioned such that an opening force of at least 10 N, preferably at least 20 N, more preferably at least 30 N can be transferred to the contact points of the contact bridge.

13. Snap-action switch according to one of the preceding claims, characterized in that in the rest position of the actuating plunger (2) a first distance (sl) between a contact point (17, 18, 19, 20) and an associated Fixed contact (21, 22, 23, 24) is less than a second distance (s2) between the stop (41, 42) and the associated counter-stop (51, 52).

14. Snap-action switch according to one of the preceding claims, characterized in that a differential distance (As) between the first distance (sl) and the second distance (s2) is between 0.1 mm and 0.3 mm.

Images