Snap switch

Abstract

Snap switch (100) with a housing (1), an actuating plunger (2) having two switching positions and at least one contact bridge (31, 32) for electrically connecting at least one first contact pair (21, 22) in a switching position, and with snap springs (8, 9) which are supported symmetrically under preload on an actuating element (3) and the actuating plunger (2), the lines of action of which are displaceable by the actuating element (3) such that the actuating plunger (2) can snap from a first switching position, in which the actuating plunger (2) is in the rest position, to a second switching position, in which the actuating plunger (2) is in the actuated position, wherein the snap switch (100) further comprises a positive opening arrangement by means of which a switching from at least the first to the second switching position is forced when a positive opening force on the actuating element (3) is exceeded. the at least one contact bridge (31, 32) having at least two contact points (314, 315; 316, 317) at one end and at the other end for electrically parallel contacting of the first contact pair (21, 22), wherein each of the contact points (314, 315, 316, 317) is designed to completely switch a rated electrical power of the snap switch (100), the snap switch has two contact bridges (31, 32) for electrically connecting at least the first contact pair (21, 22) and at least a second contact pair (23, 24), wherein the contact points of the second contact bridge (32) are also designed to completely switch a rated electrical power of the snap switch (100), characterized in that Each of the at least two contact bridges (31, 32) is assigned a reinforcement arrangement (25, 26) in the opening direction, wherein the reinforcement arrangement (25, 26) is arranged on the actuating plunger (2) and the reinforcement arrangement is formed integrally with the actuating plunger (2).

Description

[0001] The present invention relates to a snap switch according to the preamble of claim 1.

[0002] Snap switches are generally known from the prior art and typically comprise a housing, a contact bridge with two switching positions, switchable via an actuating plunger for electrically connecting fixed contacts, in particular at least one first contact pair in the first switching position and at least one second contact pair in the second switching position. Two snap springs are supported, essentially symmetrically, under preload on an actuating element and the actuating plunger, the lines of action of which are displaceable from the actuating element such that the actuating plunger can snap from the first switching position, in which the actuating plunger is essentially in its rest position, to the second switching position, in which the actuating plunger is essentially in its actuated position.

[0003] Snap switches all share the characteristic of operating with a bistable snap spring arrangement, which results in a rapid switching movement when a specific switching point is exceeded. This rapid switching movement is intended to minimize arcing and thus damage to the contact elements. Whether the spring arms are integrated with the contact bridge or designed as separate components is irrelevant for providing this function.

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

[0005] 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. Inside the housing 1, the actuating plunger 2 has a stop step that, in the plunger's rest position, rests against an inner surface of a wall of the housing 1. The actuating plunger 2 is pressed upwards into its rest position by a compression spring 4, ensuring that the stop step 3 engages securely. The actuating plunger 2 is guided in a sleeve-like receptacle in the area of ​​the compression spring 4 and in a recess in the housing 1 at one end opposite the compression spring 4.

[0006] Approximately at the midpoint 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 designed to support a V-shaped snap spring 8, 9 on one side. A contact carrier 10 is held under preload on the actuating plunger 2 by the snap springs 8, 9.

[0007] The opposite end of each of the snap springs 8, 9 is 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 and spaced apart from each other. Viewed from above, the contact arms 15, 16 are approximately O-shaped. The contact arms are held in place by the snap springs 8, 9 being under preload between the actuating plunger 2 and the spacers 13, 14, so that the spacers 13, 14 are pressed against the contact arms 15, 16 and thus fix them in their position.

[0008] The contact arms 15, 16 have end-arranged contact areas 17, 18, 19, 20, wherein fixed contacts 21, 22, 23, 24 are arranged opposite each other on the contact areas 17, 18, 19, 20, so that 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 electrically.

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

[0010] Since thermal overload of the contact points in such snap-action switches can lead to undesirable welding of the contact areas of the contact arms to the contacts of the contact pairs (i.e., the fixed contacts), lever elements for positive opening are provided in some applications. The standard DIN EN 60947-5-1, in Annex K, specifies such a rigid, positive-locking positive opening mechanism for standard snap-action switches, in addition to the snap spring mechanism, to ensure that, for safety reasons, the normally closed contact position is reliably opened when the actuating element of the snap-action switch is pressed. This positive opening mechanism is capable of opening contact points welded together by overcurrent through the application of sufficient force.These lever elements are usually pivotable over the switching plunger and can be applied at one end to the contact carrier or contact arms. When sufficient force is applied to the switching plunger, they cause the contact areas to be pressed away from the contact pairs, thus forcibly opening the switching position. To implement one of the switching positions as a rest position, as in the example shown... Fig. 9 an additional spring element in the snap switch is integrated in such a way that the position of the contact carrier in the rest position is stabilized by the force of the spring element.

[0011] Further state of the art is known from DE 19 54 449 U, CN 2 08 460 581 U and the subsequently published DE 10 2021 105 359 A1.

[0012] The well-known snap-action switches are already very reliable and suitable for safety-critical applications. However, a disadvantage is that they can fail electrically due to various factors, meaning that a conductive connection between the fixed contacts is not established, or is only insufficiently established, by the contact arms. Reasons for such a failure can include excessively high contact resistance due to dirt deposits or erosion on the contacts, as well as breakage of the snap springs or the contact bridge due to mechanical and / or thermal stress.

[0013] It is therefore the object of the present invention to improve a known snap switch.

[0014] This problem is solved by a snap-action switch with the features of claim 1. Advantageous further developments are the subject of dependent claims and the following description.

[0015] A snap switch according to the invention comprises a housing, an actuating plunger having two switching positions and at least one contact bridge for electrically connecting at least one first contact pair in a switching position, and snap springs which are supported on an actuating element and the actuating plunger in a substantially symmetrical manner under preload, the lines of action of which are displaceable from 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 actuating position, wherein the snap switch further comprises a positive opening arrangement by means of which a switching from at least the first to the second switching position is forced when a positive opening force is exceeded on the actuating element.wherein the at least one contact bridge has at least two contact points at one end and at the other end for electrically parallel contacting of the first contact pair, wherein each of the contact points is designed to completely switch a rated electrical power of the snap switch.

[0016] The design according to the invention creates electrical and mechanical redundancy, so that even if up to two contact points fail, the snap switch remains available. The contact bridge can be implemented using electrically and mechanically parallel electrical conductors, whereby, for example, with two parallel electrical conductors, the electrical or mechanical failure of one of the conductors, i.e., in this case, the two contact points associated with that conductor, can be compensated.

[0017] The snap switch can be designed as a normally open or normally closed contact, whereby the rest position of the actuating plunger defines whether it is a normally closed contact, i.e., a normally open contact, or a normally open contact, i.e., a normally closed contact.

[0018] In an advantageous embodiment, the snap switch has two contact bridges for electrically connecting at least the first contact pair and at least a second contact pair, wherein the contact points of the second contact bridge are also designed to completely switch a rated electrical power of the snap switch.

[0019] A double opener or a double closer can be implemented using two contact bridges.

[0020] If the snap switch is designed such that in the first switching position the first contact pair is connected and in the second switching position the second contact pair is connected, then the snap switch is implemented as a normally open or a normally closed contact, depending on which fixed contacts are contacted from the outside.

[0021] In an advantageous embodiment, the snap switch comprises a housing, an actuating plunger having two switching positions and at least two contact bridges for electrically connecting at least one first contact pair in the first switching position and at least one second contact pair in the second switching position, and snap springs which are supported on an actuating element and the actuating plunger in a substantially symmetrical manner under preload, the lines of action of which are displaceable by the actuating element such that the switching plunger can be snapped from the first switching position, in which the actuating plunger is substantially in its rest position, to the second switching position, in which the actuating plunger is substantially in its actuating position, wherein the snap switch further comprises a positive opening arrangement.A device by which a switch from the first to the second switching position is forced upon exceeding a forced 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 capacity of the snap switch.

[0022] A contact bridge design with at least two contact points each offers the advantage of allowing for electrically parallel contacting of the contact pairs. This compensates for the failure of one switching point per contact bridge. This means that if one contact point fails at either end of the bridge, for example due to contamination, arcing, or a mechanical defect, the snap-action switch still retains its functionality. This creates additional redundancy and increases switching reliability. The availability of the snap-action switch is thus improved.

[0023] In a configuration with two contact points per bridge end, the following contact possibilities exist when the parts of the contact bridge are cross-connected, i.e., when the contact bridge is designed such that all contact points are in electrically conductive connection with each other: Ideally, both contact points on both sides make contact. If one of the contact points fails for any reason, either on the input side and / or on the output side, at least one contact point remains functional.

[0024] The term "contact point" is used here solely to distinguish the different positions of the contacts. Contact points are therefore not necessarily point-like, but can also be linear or planar.

[0025] The term "contact pair" is also used solely for differentiation purposes. 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 include more. Preferably, however, the fixed contacts at both ends of the contact bridge comprise an identical number of contact points.

[0026] In an advantageous further development of the snap-action switch, the contact bridges are each formed in one piece. In this context, "in one piece" means that the contact bridges are manufactured entirely from the same material, which possesses both energy transmission and load-bearing properties. In contrast to the prior art, these contact bridges are thus characterized by a simple design. The material of the contact bridges is preferably both conductive and load-bearing.

[0027] A metal or metal alloy with spring properties is particularly suitable for the contact bridge. For example, spring steel can be used, although bronze, brass, nickel silver, or copper alloys are preferred due to their higher conductivity. A copper-beryllium alloy is especially preferred because it combines particularly good electrical and thermal conductivity with good mechanical properties. Copper-nickel-silicon alloys can also be used due to the good electrical and thermal conductivity achievable with these alloys, combined with good mechanical properties. Such a design ensures that the contact bridge is mechanically stable despite a small material cross-section and is adequately dimensioned for the currents to be switched.

[0028] In a preferred embodiment, the contact bridges are designed in the form of a double H-bridge, with each H-bridge having two bridge legs on either side of the actuating plunger and at least one crossbar.

[0029] The term H-bridge refers to the "H" shape of the contact bridge. This design provides two parallel contact paths for connecting the contact pairs of the fixed contacts, while simultaneously allowing cross-contact from one leg of the H-bridge to the other leg via the crossbar.

[0030] The H-bridge design also offers the advantage that the individual legs of the H-bridge can be flexible in the direction of actuation, allowing for height compensation of the individual contact points at one end of the bridge. For example, a height difference caused by a particle between the contact points at one end of the H-bridge can be compensated for using the H-bridge.

[0031] The contact bridge can further be designed such that on both sides of the actuating plunger, one bridge leg is positioned ahead and the other is positioned behind. With such a design, a contact bridge can be realized in which the contact point located on the ahead bridge leg is primarily subjected to switching arcs and the associated arcing.

[0032] In this context, "leading" means that the leading leg of the switching 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 and establishes an electrically conductive connection. The lagging contact point only contacts the fixed contact once a conductive connection already exists via the leading leg.

[0033] Conversely, when opening, this means that the lagging leg of the contact bridge breaks the electrical connection first, and only then does the leading leg open. This ensures that a switching arc is generated exclusively at the leading contact point, and only the leading contact point tends to weld to the fixed contact, since it switches higher currents compared to the lagging contact.

[0034] In a preferred embodiment, the material of each contact point can be adapted accordingly. In particular, the contact points on the leading legs can be designed to be more resistant to abrasion. Suitable materials for the contact points of the leading leg include, for example, silver, gold, or silver or gold alloys.

[0035] Conversely, the lagging leg may have contact points made of a highly conductive but less resistant material, e.g., gold.

[0036] Under mixed loads, the leading contact point switches the high currents and is therefore subjected to a corresponding load. The lagging contact point switches when the contact resistance of the leading contact point becomes too high at lower currents. The lagging contact can use a contact material more suitable for lower loads, as it does not switch high loads.

[0037] In another embodiment, the contact bridges are spring-loaded. This allows manufacturing tolerances to be compensated for and ensures reliable contact, for example, by compensating for differences in particle height. Furthermore, a spring-loaded design of the contact bridges can facilitate the opening of the snap switch. The metals and metal alloys already mentioned above for the contact bridge design are particularly suitable materials.

[0038] Reliable contacting can also be achieved if the contact bridges are designed and the contact points are arranged in such a way, and relative to the contact pairs, that the contacts are self-cleaning.

[0039] Self-cleaning of the contacts can be achieved, for example, by designing the contact points and contact pairs in such a way and arranging them relative to each other that a lateral movement is caused between the contact point and the contact pair, at least when the contacts are closed.

[0040] Such lateral movement, for example, removes and clears away deposits caused by burning, thus ensuring reliable contact at all times.

[0041] For example, if the contact bridge is made of a spring-elastic material, then, with an existing electrical connection (i.e., when the contact points are already in contact with the contact pairs), a further movement of the contact bridge in the closing direction can cause a lateral movement of the contact points and the contact pairs relative to each other, thereby rubbing off deposits and simultaneously pushing them away from the contacts.

[0042] According to the invention, each of the at least two contact bridges is associated with a reinforcing arrangement in the opening direction. This reinforcing arrangement is located on the actuating plunger and is formed integrally with the plunger. The reinforcing arrangement allows the contact bridges themselves to be dimensioned less robustly while still maintaining sufficient stability. Such a reinforcing arrangement can be particularly advantageous in the opening direction, as welds potentially caused by thermal stresses may need to be released in this direction. Simultaneously, a reinforcing arrangement located solely in the opening direction ensures both flexibility in the closing direction and sufficient stability in the opening direction.

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

[0044] By arranging the reinforcement assembly, and in particular by forming the reinforcement assembly and the actuating plunger in one piece, a particularly space-saving and, in particular, manufacturing-technically simple implementation can be achieved.

[0045] The reinforcement arrangement can, for example, be designed as a molded-on feature extending from the actuating plunger in the direction of the contact bridge, particularly in the form of reinforcing arms. Such molded-on features can be implemented particularly easily during the manufacture of the actuating plunger, for example, using plastic injection molding, and can be produced in the necessary dimensions.

[0046] It is preferred that the shaped sections support the bridge legs, at least in the uncontacted state, for at least 1 / 5, preferably at least 1 / 4, more preferably at least half, and particularly preferably at least 3 / 4 of the area projecting beyond the actuating plunger. The larger the contact area of ​​the legs of the contact bridge on the shaped sections, the greater the support effect in the opening direction, so that support of more than 3 / 4 can also be advantageous. The increased support effect is achieved by reducing the overhang, i.e., the length by which the contact bridge projects beyond the shaped section, through a larger contact area. An opening force acting on the actuating plunger is thus transferred to the contact bridge over a larger area, and at the same time, the freely projecting length of the contact bridge is reduced. A force acting against the opening, e.g.,By welding the contact point to the fixed contact, a reduced lever arm is achieved, so that buckling of the contact bridge is less of a concern.

[0047] In a preferred embodiment, the projections are shaped such that they pre-tension the contact bridge. A preferred embodiment is one in which the projections on the actuating plunger bend a contour of the contact bridge, so that it advantageously has a defined pre-tension.

[0048] Pre-tensioning the contact bridge offers several advantages. Manufacturing tolerances of the contact bridge can be compensated for without the need for rework, as the molded features position the contact bridge precisely. Furthermore, this allows the contact bridge to have a defined pre-tension, thus providing an increased force for opening the contacts immediately in the opening direction.

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

[0050] The contact bridge can be designed, in particular, as a stamped and bent part. Stamped and bent parts can be manufactured cost-effectively and to a high standard.

[0051] Alternatively, especially for smaller production runs, other manufacturing methods can be used. For example, various cutting processes, such as water jet or laser cutting, followed by a bending step can be employed.

[0052] To reliably transmit a prescribed opening force for a forced opening of the rest position, the molded features are dimensioned such that an opening force of at least 10 N, preferably 20 N, and more preferably 30 N, can be transmitted to the contact points of the bridge legs. This ensures that the snap switches according to the present application also comply with the standard DIN EN 60947-5-1. The molded features also make it possible to transmit higher forced opening forces than the 20 N required by the standard, so that a transmission of 30 N and more can be achieved.

[0053] 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 thereby fixed.

[0054] In an alternative embodiment, the contact bridge is overmolded with the actuating plunger. This embodiment has the advantage of being particularly cost-effective, reducing the number of components of the snap-action switch, and offering particularly secure attachment of the contact bridge, as the contact bridge is positively and non-positively fixed in the area of ​​the actuating plunger.

[0055] All contacts, both on the contact bridge and the fixed contacts, can be cylindrical, flat, or spherical / oval (contact rivet). With spherical contacts, the contact surface is point-like; with cylindrical contacts, it is linear; and with two-surface contacts, it is flat.

[0056] The self-cleaning mechanism of the switching points can be designed to be either sliding or pulling. Depending on the angle at which the contact points and contact pairs meet, a sliding or pulling relative movement is performed between the contacts. Further details can be found in the exemplary embodiments described below.

[0057] Advantageous embodiments and variants of the invention are described in the dependent claims and the following description. The features listed individually in the dependent claims can be combined with each other and with the features explained in more detail in the following description in any technically sensible manner, and represent other advantageous embodiments of the invention.

[0058] The present invention is explained in detail below with reference to exemplary embodiments and the accompanying figures. These show: Fig. 1 a first embodiment of a snap-action switch according to the present application in simplified representation, Fig. 2 a schematic diagram of the actuating plunger with the first contact bridge and associated fixed contacts, Fig. 3a) to c) a closing operation of a contact bridge of the snap switch according to Fig. 2, Fig. 4a) to c) an opening process of the contact bridge Fig. 3, Fig. 5a) and Fig. 4b) an alternative design form of a contact bridge when closing ( Fig. 5a)) and opening ( Fig. 5b)), Fig. 6 a third design form of a contact bridge, Fig. 7 a fourth embodiment of a contact bridge, Fig. 8a) and Fig. 7b a contact bridge with a leading and a lagging bridge leg and Fig. 9 a snap-action switch in accordance with the state of the art (already discussed).

[0059] In the figures, unless otherwise indicated, identical reference symbols denote identical or corresponding components with the same function.

[0060] Fig. Figure 1 shows a first embodiment of a snap switch 100 according to the present application.

[0061] The snap-action switch 100 is simplified in the illustration and shown with its housing open, so that the functionality of the components located in the snap-action switch 100 becomes clearer. 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 is moved by means of an actuating element 3 between a first switching position, as described in Fig. 1 is shown and can be switched to a second switching position in which the actuating plunger 2 is in a position shifted 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 which are supported parallel to each other on the switching element 3 and the actuating plunger 2, so that actuation of the actuating element 3 shifts the characteristic curves of the snap springs 8, 9 such that the actuating plunger 2 snaps 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 Fig. The first switching position shown in Figure 1 is stabilized by the compression spring 4.

[0062] The in Fig. The snap-action switch 100 shown in Figure 1 further comprises a positive opening mechanism consisting of a first positive opening lever 5 and a second positive opening lever 6. The positive opening levers 5 and 6 are supported at one end by a circumferential collar of the actuating plunger 2 and are slidably mounted at the other end in the housing of the snap-action switch 100. When a predetermined actuating force is applied via the actuating element 3, it comes into contact with the positive opening levers 5 and 6 and, by tilting the positive opening levers 5 and 6, indirectly mechanically couples the actuating element 3 to the actuating plunger 2 via the positive opening levers 5 and 6. This ensures that, if the actuating plunger 2 fails to snap from the first switching position to the second switching position, a mechanically forced switching occurs.

[0063] As already described in relation to the prior art, such a forced opening may be necessary if, for example, due to thermal stresses, the contacts of the snap switch 100 are welded together in a switching position (in this case, the first switching position) and the snap springs 8, 9 are therefore unable to release the contacts and change the switching position.

[0064] In the present case in Fig. In the snap-action switches 100 shown in Figure 1, a first contact bridge 31 and a second contact bridge 32 are arranged on the actuating plunger 2, wherein in the Fig. In the first switching position of the actuating plunger 2 shown in Figure 1, the first contact bridge 31 with its associated fixed contacts 21, 22 is not in contact, and the second contact bridge 32 electrically connects a third fixed contact 23 and a fourth fixed contact 24. For contacting the respective fixed contacts 21, 22, 23, 24, the contact bridges 31, 32 have contact points arranged at their ends, which reinforce the contact bridges and thus make them wear-resistant.

[0065] Fig. Figure 2 shows a schematic diagram of the actuating plunger 2 with the first contact bridge 31 and the fixed contacts 21, 22 associated with it in the second switching position.

[0066] The following statements regarding the first contact bridge 31 also apply mutatis mutandis to the second contact bridge 32.

[0067] The representation in Fig. Figure 2 is greatly simplified and is intended primarily to explain the operating principle of the depicted embodiments. The first contact bridge 31, now shown in detail, is held in a recess of the actuating plunger 2. In the depicted embodiment, the first contact bridge 31 is designed as a so-called H-bridge, whereby the contact bridge 31, viewed from above, resembles the letter "H" and has two parallel bridge legs 311, 312, which are connected by means of a Fig. The two bridge legs 311 and 312 are connected to each other by a crossbar 313 that is not visible. Reinforced contact points 314, 315, 316, and 317 are arranged at the ends of the bridge legs 311 and 312, reinforcing the contact bridge 31 and thus making it wear-resistant. In the embodiment shown here, the contact points 314-317 are designed as cylindrical reinforcement surfaces welded onto the ends of the bridge legs 311 and 312. The cylindrical shape, which extends transversely to the direction of extension of the bridge legs 311 and 312, creates a linear contact surface between the fixed contacts 21 and 22 (which are flat in this embodiment) and the contact points 314-317, over which an electric current flows.

[0068] In contrast to the prior art, the contact bridge 31 is not designed in the form of a contact carrier, i.e., in particular, as a solidified structure, but rather as a concavely bent leaf spring which, in the opening direction (i.e., when an electrical contact closed between contact points 314-317 and the fixed contacts 21, 22 is reopened), is supported by a reinforcing arrangement in the form of reinforcing arms 25, 26 located on the actuating plunger 2. In the present embodiment, the reinforcing arms 25, 26 are integrally formed with the actuating plunger 2 and support the contact bridge 31 in the opening direction, as described below in conjunction with Fig. 3 will be explained in more detail.

[0069] Fig. 3 shows in the Fig. 3a) to 3c) the arrangement of Fig. 2 in a top view from the front when the contact between the contact bridge 31 and the fixed contacts 21, 22 is closed.

[0070] In Fig. 3a) shows how the actuating plunger 2 moves from the first switching position, in which - as in Fig. Figure 1 shows the second contact bridge 32 moving the fixed contacts 23, 24 into the second switching position, in which a 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 determined by the Fig. 3a) indicated by the arrow. In the first part of the figure, it is clearly visible that the bridge legs 311, 312 extending on both sides of the actuating plunger 2 (in this illustration, this is the forward-pointing bridge leg 312) bear 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 initially follow the contour of the reinforcement arms 25, 26 with a positive curvature and then bend with a negative curvature towards the horizontally extending fixed contacts 21, 22.

[0071] Fig. Figure 3b) shows the point in time at which the contact points 315-317 of the 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, since at this time there is contact between the 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 switch according to the present application, the contact points formed by the contact points 314-317 and fixed contacts 21, 22 are designed to be self-cleaning. This means that particles, deposits, or deposits caused by material abrasion on the fixed contacts 21, 22 or the contact points 314-317 are mechanically loosened and pushed away.In the present embodiment, this is achieved by the actuating plunger 2 starting from the in . Fig. 3b) In the situation shown, where contact already exists between contact points 314-317 and fixed contacts 21, 22, the contact bridge 31 is moved further in the direction shown, causing it to be slightly bent. This results in lateral movement between the fixed contacts 21, 22 and contact points 314-317. This lateral movement guides contact points 314-317 along the fixed contacts 21, 22, so that the friction generated at the contact points loosens deposits and particles, pushing them outwards. This ensures a permanently low contact resistance between contact points 314-317 and fixed contacts 21, 22, thus increasing the reliability of the snap-action switch 100.

[0072] In addition, the contact bridges 31, 32, which are designed with individual bridge legs 311, 312, ensure that in the event of deposits and particles on one of the contact partners, a 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 - thereby making an electrical contact even more reliable.

[0073] The Fig. Figures 4a) to c) show an opening process of the contact bridge 31. Fig. 3.

[0074] Fig. 4a) shows the in Fig. 3c) Situation achieved after the complete closure of the contact bridge 31 Fig. 3. As through the in the Fig. As indicated by the arrows shown in 4a) to c), the actuating plunger 2 now moves downwards, i.e., away from the fixed contacts 21, 22, so that the electrical connection between the fixed contacts 21, 22 and the contact points 314-317 of the contact bridge 31 is broken 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 immediately detach when the contact bridge 31 rests against the reinforcing arms 25, 26.

[0075] Fig. Figure 4b) shows the position of the actuating plunger 2 in which the bridge legs 311, 312 of the contact bridge 31 bear against the reinforcing arms 25, 26 of the actuating plunger 2. Subsequently, by a further movement of the actuating plunger 2 away from the fixed contacts 21, 22, the contact points 314-317 are released from the fixed contacts 21, 22. Through this further movement of the actuating plunger 2, the force is introduced into the contact bridge 31 in the direction of movement via the reinforcing arms 25, 26. The reinforcing arms 25, 26 further reinforce and stiffen the contact bridge 31 in this direction. In this way, it is possible, contrary to the spring-elastic design of the contact bridge 31, to apply an increased opening force to the welded contact point, so that it opens reliably.

[0076] In this configuration, contact points 314-317 are subtracted from fixed contacts 21, 22, i.e., a tensile force acts in contact bridge 31.

[0077] In the Fig. 5a) and Fig. 5b) is an alternative design form of a contact bridge 31 when closing ( Fig. 5a)) and opening ( Fig. 5b)) shown.

[0078] The contact bridge 31 points in the Fig. In the embodiment shown in Figure 5, the overall design is convex, with the reinforcing arms 25, 26 arranged on the actuating plunger 2 being inclined downwards. The fixed contacts 21, 22 are also inclined relative to the horizontal in accordance with the inclination of the contact bridge 31 in the area of ​​contact points 314-317, so that, as in Figure 5, the contact bridge 31 is inclined relative to the horizontal. Fig. 5a) shows self-cleaning in the case of contact between the contact points 314-317 and the fixed contacts 21, 22, unlike in the design according to Fig. 3 leads to the displacement of particles, but due to the changed contact situation this lateral movement between contact points 314-317 and the fixed contacts 21, 22 is a pulling movement directed towards the actuating plunger 2.

[0079] In accordance with the changed contact situation, contact points 314-317 will be replaced by fixed contacts 21, 22 as in Fig. 5b) shown when opening rather pressed down, i.e. a pressure force acts in the contact bridge here, which releases the contact points 314-317 from the fixed contacts 21, 22.

[0080] Unlike the one in the Fig. The design of contact points 314-317, as shown in 2-4, is in the design of the Fig. 5 the contact points 314-317 are designed as flat contacts and the fixed contacts 21, 22 as cylindrical contacts.

[0081] Fig. Figure 6 shows a more detailed representation of another embodiment of the contact bridge 31, as it is also arranged according to Fig. 1 can be used.

[0082] The in Fig. 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 and 312 are connected to each other centrally by the crossbar 313 and are each subdivided into two bridge leg sections 311a, 311b, 312a, and 312b extending from the crossbar 313.

[0083] In the present embodiment, the crossbeam 313 is arranged centrally, so that the bridge leg sections 311a, 311b, 312a, 312b each extend symmetrically from the crossbeam 313 at right angles to it. The bridge legs 311, 312 are, as already described with regard to the design of the Fig. As explained in Figure 2, the contact bridge 31 is initially formed with a positive curvature and subsequently extends with a negative curvature, such that the contact bridge 31 is concave in a central area and convex at 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, and in this 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 ends with a rivet.

[0084] In the present embodiment, the crossbar 313 is designed such that it extends linearly between the bridge legs 311, 312 with a semicircular projection on both sides of the bridge legs 311, 312. This projection can be used to align and center the contact bridge 31 within the actuating plunger 2 and thus provides an assembly aid. Fig. Figure 7 shows a further embodiment of a contact bridge 31, wherein the Fig. The contact bridge 31 shown in Figure 7 has a completely convex profile. The convex profile of the contact bridge 31 necessitates a modified contact geometry and self-cleaning, as is the case, for example, in Fig. 5 is shown. Also in the embodiment of the Fig. 7. Contact points 314-317 are designed as contact rivets.

[0085] The Fig. 8a) and Fig. Figure 8b) shows a modified embodiment of the contact bridge 31 from Fig. 6.

[0086] Unlike the one in Fig. In the embodiment of the contact bridge 31 shown in section 6, in which both bridge legs 311, 312 are designed to run parallel to each other, the contact bridge 31 is designed according to Fig. 8a) designed such that one bridge leg is leading and the other bridge leg is lagging.

[0087] In this context, "leading" means that the contact point located on the leading bridge leg, when moving in the closing direction, contacts the associated fixed contact before the lagging contact point, thus establishing an electrically conductive connection before it. Conversely, when the switch opens, the lagging bridge leg, or its associated contact points, first lifts off the respective fixed contact, and the leading bridge leg (in the closing direction) then breaks the connection.

[0088] In the Fig. In the embodiment shown in Figure 8, the first bridge leg 311, and thus also its associated contact points 314, 316, is leading, while the second bridge leg 312, with its associated contact points 315, 317, is lagging. This configuration results in increased current densities, and consequently, flashovers and resulting wear, primarily affecting the contact points of the leading, first bridge leg 311 when the contacts open. By selecting a suitable material, the leading bridge leg can, for example, be equipped with contact points made of a material more resistant to wear, whereas the lagging bridge leg can have contact points made of a highly conductive material, which, however, is more susceptible to flashovers and therefore more sensitive.

[0089] Fig. 8b) shows a close-up of a section from Fig.8a), from which it is particularly clear how a leading and a lagging bridge leg can be realized. In the present embodiment, the bridge legs are bent such 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 Δh and is thus leading in the closing direction.

[0090] In an alternative embodiment, the contact rivets used could also have different heights, so that while the bridge legs are curved identically, the contact rivets of the leading contact point are taller than those of the trailing contact point. Such a design can provide a greater material thickness for the leading contact point, giving it not only a more abrasion-resistant material but also additional material thickness that can be worn away. Reference symbol list 1 case 2 actuating plungers 3 Actuating element 4 compression springs 5 first forced opening lever 6 second forced opening lever 8 first snap spring 9 second snap spring 11, 12 recording notch 13, 14 spacer 15 upper contact arm 16 lower contact arm 17 first point of contact 18 second contact point 19 third contact point 20 fourth contact points 21 first firm 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 switches 311 first bridge leg 312 second bridge leg 313 Crossbeam 314-317 Contact points

Claims

[1] Snap switch (100) with a housing (1), an actuating plunger (2) having two switching positions and at least one contact bridge (31, 32) for electrically connecting at least one first contact pair (21, 22) in a switching position, and with snap springs (8, 9) which are supported symmetrically under preload on an actuating element (3) and the actuating plunger (2), the lines of action of which are displaceable from the actuating element (3) such that the actuating plunger (2) can be snapped from a first switching position, in which the actuating plunger (2) is in the rest position, to a second switching position, in which the actuating plunger (2) is in the actuating position, wherein the snap switch (100) further comprises a positive opening arrangement by means of which a switching from at least the first to the second switching position is forced when a positive opening force on the actuating element (3) is exceeded, the at least one contact bridge (31, 32) having at least two contact points (314, 315; 316, 317) at one end and at the other end for electrically parallel contacting of the first contact pair (21, 22), wherein each of the contact points (314, 315, 316, 317) is designed to completely switch a rated electrical power of the snap switch (100), the snap switch has two contact bridges (31, 32) for electrically connecting at least the first contact pair (21, 22) and at least a second contact pair (23, 24), wherein the contact points of the second contact bridge (32) are also designed to fully switch a rated electrical power of the snap switch (100), characterized by , that Each of the at least two contact bridges (31, 32) is assigned a reinforcement arrangement (25, 26) in the opening direction, wherein the reinforcement arrangement (25, 26) is arranged on the actuating plunger (2) and the reinforcement arrangement is formed integrally with the actuating plunger (2). [2] Snap switch (100) according to claim 1, characterized by , that in the first switching position the first contact pair (21, 22) is connected and in the second switching position the second contact pair (23, 24) is connected. [3] Snap switch (100) according to one of the preceding claims, characterized by , that the contact bridges (31, 32) are each formed in one piece. [4] Snap switch (100) according to one of the preceding claims, characterized by , that the contact bridges (31, 32) are designed in the form of a double H-bridge, with two bridge legs (311, 312) on either side of the actuating plunger (2) and at least one crossbar (313). [5] Snap switch (100) according to one of the preceding claims, characterized by , that the contact bridges (31, 32) are designed such that on both sides of the actuating plunger (2) one bridge leg (311) is designed to lead and the other bridge leg (312) is designed to lag. [6] Snap switch (100) according to one of the preceding claims, characterized by , that the contact bridges (31, 32) are designed to be spring-elastic. [7] Snap switch (100) according to one of the preceding claims, characterized by , that the contact bridges (31, 32) are designed and the contact points (314-317) are arranged and are arranged relative to the contact pairs (21, 22, 23, 24) in such a way that the contacts are self-cleaning. [8] Snap switch (100) according to claim 7, characterized by, that the contact points (314-317) and the contact pairs (21, 22, 23, 24) are designed and arranged relative to each other in such a way that at least when the contacts are closed a lateral movement is caused between the contact point (314-317) and the contact pair (21, 22, 23, 24). [9] Snap switch (100) according to one of the preceding claims, characterized by , that the reinforcement arrangement is designed as a shaping 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 reinforcement arms (25, 26). [10] Snap switch (100) according to claim 9, characterized by that the shaped sections support the bridge legs at least in the contacted state to at least 1 / 5, preferably at least 1 / 4, more preferably at least half, particularly preferably 3 / 4. [11] Snap switch (100) according to one of claims 9 or 10, characterized bythat the molded shapes are designed in such a way that the contact bridges are prestressed. [12] Snap switch (100) according to any one of claims 9 to 11, characterized by that the molded parts are 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 bridge legs (311, 312).

Images