This invention concerns a switching contact for an electrical switching device having a leaf spring-shaped actuator section.

The invention further concerns an electrical switching device. Electrical switching contacts and switching devices of the aforementioned type are known from the prior art. The switching contacts perform switching functions in electrical switching devices such as relays or other electrical switching elements. The switching devices have drive systems that move at least one switching contact via actuators, in order to bring a counter contact into electrically conductive contact or remove it therefrom. The actuators thus move one or more switching contacts in one switching direction towards the counter contacts or, in a counter switching device, away from them, and maintain a circuit formed by the contacts and counter contacts arranged at the switching contacts in a closed or open state.

In switching devices such as protectors or relays, contact forces acting in the switching direction are applied by drive systems driving the actuator that brings the contacts into contact with the counter contacts. In order to ensure secure, uninterrupted contact between the switching contacts and the counter contacts, in particular in the event of vibrations or pulses that may act on the switching device, and thus on the switching contact, the drive system and the actuator may be designed, e.g., such that they move the switching contact with overtravel in the direction of the counter contact. A contact on the switching contact thus comes into contact with the counter contact before the actuator has reached its final position, i.e., the closed or closing position of the switching device. In other words, a switching path followed by the switching element on the switching contact to transfer it from an open position of the switching contact into the closed position, is shorter than an actuation path followed by the actuator acting on the switching contact when transitioning from the open to the closed position. In the closed state, the actuation section is thus subject to a tensioning force with which the contact of the switching contact is kept in contact with the counter contact.

To release the switching contact from the counter contact during the transition of the switching device from the closed to the open position, a resetting force must be generated acting against the switching direction, i.e., in the counter switching direction. This resetting force may also be generated by the actuator, as well as a spring section of the switching contact.

In particular in switching devices used for high currents, however, problems may arise during the transition from the closed into the open state, i.e., during opening, if the switching contact or its contact element is welded to the counter contact. This may occur in particular when, in the event of malfunctions of an apparatus containing the switching device, short circuit currents, e.g., of more than 3000 A, occur. In the worst-case scenario, the counter switching forces in the counter switching direction that are required for opening cannot be transferred via the actuation section to the switching contact to the degree necessary to release the switching contact from the counter contact.

Given the aforementioned problems of prior-art switching contacts and switching devices, the invention seeks to provide switching contacts and switching devices that can be reliably opened even under short circuit conditions. This problem is solved for the aforementioned switching contact in that the actuation section is less rigid in a switching direction than in a counter switching direction running counter to the switching direction.

In the aforementioned switching device, the problem is solved by using at least one switching contact according to the invention. This solution, which may, at first glance, appear simple, has the advantage that the forces required to release any welding of the switching contact or its contact element to the counter contact can be induced as quickly as possible into the contact area between the contact and the counter contact. Thus, a weld can be more easily broken. The increased rigidity also reduces the necessary travel of the actuator compared to prior-art switching devices in order to achieve the necessary distance between the contacts in the open state of the switching device. This allows the drive system and the actuator to be designed such that the actuator generates a greater speed than prior-art switching devices before acting on the contact, and is thus able to accelerate it like a higher pulse in order to break any welds between the contact and the counter contact. For example, the switching contact may have a contact section, on which the switching contact can be moved or elastically bent in the switching and counter switching directions, to receive at least one electrical contact as well as the actuation section extending away from the contact section. The actuation section is more rigid in the counter switching direction than the switching direction. In other words, the actuation section may be more elastic or have a higher elasticity than in the counter switching direction. Thus, a switching contact according to the invention has an actuation section with a direction-dependent rigidity or elasticity. Tensile forces, in particular in the counter switching directions, can thus be better transferred from the actuation to the contact section than compressive forces in the switching direction.

The solutions of the invention can be further improved by various embodiments, each of which is advantageous in itself, which can be combined with one another as desired.

The actuation section may have a brace structure. The brace structure allows the rigidity of the actuation section in the counter switching direction to be greater than the rigidity of the actuation section in the switching direction. The brace structure may advantageously be designed such that at least the actuation section of the switching contact can be produced as easily as possible, without any significant increase in materials used, despite the increased rigidity in the counter switching direction. Alternatively or additionally, the actuation section may have a weakening structure in order to influence the rigidity of the contact as desired.

The weakening structure may be configured as a bend in an edge area of the contact. The height of the bent section of the edge area allows the rigidity of the actuation section to be adjusted as desired. Alternatively, for example, rib structures or corrugations may be formed in the actuation section to contribute to the increased rigidity of the actuation section in the counter switching direction. The weakening structure, on the other hand, may be formed, e.g., as a recess, slit, or opening.

The actuation section may comprise a first spring element and at least one additional spring element, which run, at least in sections, substantially along a longitudinal extension of the actuation section, whereby the first spring element has a lower rigidity, substantially perpendicularly to the longitudinal extension, than the at least one other spring element. The first spring element may face in the switching direction, and the at least one other spring element may face in the counter switching direction. Both spring elements may be made of substantially the same material, or have substantially the same thickness or material strength. The spring elements may abut one another, and one of the spring elements, in particular the at least one additional spring element, may support another of the spring elements, in particular the first spring element, in the counter switching direction.

The at least one other spring element may be broader than the first spring element, at least in part perpendicularly to the switching direction. Thus, the at least one spring element may be more rigid than the first spring element simply due to its greater breadth than the first spring element.

The first spring element may protrude beyond the at least one other spring element in the area of the actuation section. Thus, the first spring element may be longer than the at least one additional spring element, and thus be less rigid over its entire length than the at least one additional spring element. The first spring element may form an actuator end of the switching contact. The actuator of the switching device may interact with the switching contact at the actuator end or move it in the switching direction and the counter switching direction. At least in the area of the actuator end, the first spring element may be designed so as to be able to bend away from the at least one additional spring element. For example, the first spring element may be designed so as to be able to bend away elastically from the at least one additional spring element up to the contact section of the switching contact. Thus, the first spring element may act as an overtravel spring that lifts away from the at least one additional spring element, substantially in the switching direction, once the closed position is reached, i.e., when the contact abuts the counter contact. During opening, the first spring element may be brought to bear on the at least one other spring element again, and thus be supported by it, in order to provide the desired increased rigidity of the actuation section in the counter switching direction.

At least one section of the at least one other spring element may run between the first spring element and an additional spring element. The additional spring element may serve to improve the spring properties of the switching contact. The additional spring element may extend substantially from one attachment end of the switching contact up to the actuation section. A spring section of the switching contact may extend at least from the attachment end to the contact section. The additional spring element may end at the contact section, or between the contact section and the actuation section. Thus, the additional spring element may be used, in particular, to improve the spring properties of the switching contact in the spring section, in particular with regard to the desired resetting forces, e.g., the hardness and thus the spring forces of the spring section.

In the aforementioned switching device, the solution according to the invention may be further improved, e.g., in that the first spring element faces in one switching direction in which an electrical contact of the switching contact is arranged so as to be able to be brought together with a counter contact of the switching device. The actuator may act on the first spring element, which allows the advantages referred to above with regard to the actuation end to be realised. The drive system and the actuator of the switching device may, accordingly, be configured and designed such that, on the one hand, the desired overtravel is possible and, on the other, the contact can be moved as quickly and as forcefully as possible from the closed to the open position in order to break any weld between the contact and the counter contact.

The invention is explained in greater detail below by way of example, by reference to possible embodiments and the related drawings. The combinations of characteristics shown in these embodiments are merely illustrative. Individual characteristics may be omitted depending on their aforementioned benefits if those benefits are of no importance to particular applications.

In the description of the embodiments, the same characteristics and elements are provided with the same reference numerals for the sake of simplicity. Characteristics and elements having the same, or at least a similar, function, generally have the same reference numeral or letter as is used to designate another embodiment, with one or more apostrophes.

The drawings show the following: Fig. 1 A schematic side view of a first embodiment of a switching device according to the invention with a first embodiment of a switching contact according to the invention in the open position;

Fig. 2 A schematic perspective view of the switching contact shown in fig. 1;

Fig. 3 The switching device shown in fig. 1 in a closed position;

Fig. 4 A schematic side view of a second embodiment of a switching device according to the invention with a second embodiment of switching contacts according to the invention in the open position;

Fig. 5 A schematic perspective view of a second embodiment of a switching contact according to the invention;

Fig. 6 A detailed schematic perspective view of the switching contact shown in fig. 5;

Fig. 7 A schematic perspective view of a third embodiment of a switching contact according to the invention;

Fig. 8 A detailed schematic perspective view of the switching contact shown in fig. 7; and

Fig. 9 A schematic perspective view of a fourth embodiment of a switching contact according to the invention;

Fig. 1 shows a schematic perspective view of a first embodiment of a switching device 1 according to the invention. The switching device 1 extends in a longitudinal direction X, a transverse direction Y perpendicular to the longitudinal direction X, and a height direction Z perpendicular to the longitudinal direction X and the transverse direction Y, forming together a Cartesian coordinate system. The switching device 1 comprises a switching contact assembly 2, a drive system 3, an actuation system 4, and a housing 5, containing the switching contact assembly 2, the drive system 3, and the actuation system 4.

The switching contact assembly 2 comprises an electrical switching contact 6 and a support 7. The switching contact 6 comprises a first spring element 6a and an additional spring element 6b, and extends from an attachment end 8 to an actuation end 9. In the area of the attachment end 8, the switching contact 6 has an attachment section 10, in which the switching contact 6 is attached to the support 7, e.g., by attaching the first spring element 6a and the additional spring element 6b close together on the support 7, as in this embodiment. For example, the first spring element 6a and the additional spring element 6b may be force- or form-fitting with the support 7. In this case, the attachment section 10 is riveted to the support 7.

A spring section 11 , in which the first spring element 6a and the additional spring element 6b run substantially parallel to one another, is attached to the attachment section 10. A contact section 12, followed by an actuation section 13, on which the attachment end 9 is formed, is attached to the spring section 11. In the spring section 11, the first spring element 6a has a bend 14 influencing the spring properties of the spring section 11. In the contact section 12, a contact 15 that forms a contact surface 16, configured in a switching direction S so as to be able to be brought together with a counter contact surface 18 that is formed by a counter contact 17, is arranged on the switching contact 6. In a counter switching direction S', the contact 15 can be separated from the counter contact 17. In an open position O of the switching device 1, shown in fig. 1, the contact surface 16 is kept at a distance from the counter contact surface 18 by means of a switching path W. An electrical connection 19 is formed on the support 7, which is thus conductively connected with the switching contact 6 and the contact 15 arranged thereon, and serves to connect electrical components to it outside of the switching device 1. An electrical counter connection 20, also leading outside the housing 5, is formed on a counter support 21 containing the counter contact 17.

The drive system 3 is configured, e.g., as an electromotive drive with an electrical coil, a magnetic core, and a yoke, and has three control connections 22a, 22b, and 22c, via which the drive system 3 can be supplied with electrical control, supply, or switching voltage. The supply connections 12 may, like the electrical connection 19 and the electrical counter connection 20, be designed as contact pins, solder tails, etc. The drive system 3 may act, e.g., on a hinged armature 23 of the actuation system.

The actuation system 4 comprises an actuator in the form of a slider 24, which is driven via the hinged armature 23 interacting with the drive system 3. The slider 24 is received on the body, and is movable substantially parallel to the mating direction S or the counter mating direction S', and has a make contact 25 and a break contact 26 as actuators, which are spaced apart substantially parallel to the switching direction S or the counter switching direction S' by an actuation distance d. The make contact 25 provides an actuation surface facing substantially in the switching direction S, designed so as to press the switching contact 6 in the area of the actuation end 9 in the switching direction S with a switching force F _s . The break contact 26 provides an actuation surface facing substantially against the switching direction S, i.e., in the counter switching direction S', and is designed to move the switching contact 6 in the area of the actuation end 9 with a counter switching force F _s' in the counter switching direction S', and to keep it in the open position, as shown in fig. 1. Together with a spring force F _f exercised by the spring section 11 of the switching contact 6, the switching force F _s and counter switching force F _s' are added to a counter resetting force F _R' in the switching direction S or a resetting force F _R acting in the counter switching direction S'.

A schematic perspective view of the switching contact 6 is shown in fig. 2. In the area of the actuation section 13, a free end 27 of the first spring element 6a protrudes beyond another free end 28 of the additional spring element 6b. Thus, the actuation end 9 formed by the first spring element 6a is free. From the additional free end 28 to a point at which the first spring element 6a and the additional spring element 6b are connected in the contact section 12, a brace structure 29 extends along the additional contact 6b. The brace structure 29 is formed as an on-bend of an edge area 30 of the additional spring element 6b facing substantially against the switching direction S'.

Additionally, the additional spring element 6b widens from the additional free end 28 to the actuation section 12; on the other hand, the spring element 6a is substantially linear in this area and narrower than the additional spring element 6b. Because the additional spring element 6b has the brace structure 29 and/or is wider than the first spring element 6a, the additional spring element 6b is more rigid than the first spring element 6a, at least in the actuation section 13.

In the contact section 12, for example, two of the contacts 17 are attached to the contact 6 with connection means 31. The connection means 31 may be, e.g., screws, rivets, etc. Thus, the first spring element 6a and the second spring element 6b may be force- and/or form-at least at one point in the contact section. From the contact section 12, the two spring elements 6a and 6b run in contact with one another and with substantially the same outer contour, apart from the area in which the bend 14 is arranged, up ot the attachment section 10. In the attachment section 10, the series of attachment openings 32 are formed, in which the switching contact 6 can be connected using form fitting elements, e.g., rivets, and simultaneously the first spring element 6a can be connected with the additional spring element 6b. Additionally, fig. 2 shows that the switching contact 6 forms a first switching unit 33a and a second, or at least one additional, switching unit 33b, which are connected in a bridgelike connection area 34 in the attachment section 10 and separated from one another by a slit 35 running along a central axis M extending parallel to the longitudinal extension L of the switching contact 6, and are thus each independently movable from the connection area up to the actuation end 9. The first switching unit 33a and the additional switching unit 33b thus each comprise an attachment section 10, a spring section 11, a contact section 12, and an actuation section 13.

Fig. 3 shows a schematic perspective view of the switching device 1 in the closed position C. The drive system 3 has turned the hinged armature 23 around its rotational axis R to such an extent that it has moved the slider 24 in the switching direction S up to the closed position C. The contact 16 has traversed the switching path W whilst abutting the make contact 25 and guided by it, and abuts the counter contact 17. Beyond the switching path W, the slider 24 has executed an overtravel U in the switching direction S from the open position, thus raising the actuation end 27 away from the additional free end 28. Thus, the contact surface 16 of the contact 15 is held on the counter contact surface 18 of the counter contact 17 under spring tension from the actuation section 13 of the first spring element 6a. The actuation section 13 of the first spring element 6a forms an overtravel spring.

By contrast, in the open position shown in fig. 1, the actuation section 13 of the first spring element 6a abuts the actuation section 13 of the additional spring element 6b. The additional spring element 6b thus forms a support section in the actuation section 6b, in which it supports the actuation section 13 of the first spring element 6a in the counter switching direction S' when the contacts 16 and 17 are opened or separated, i.e., during the transition of the switching contact 6 from the closed position C to the open position O. Thus, an overtravel can be generated in the switching direction S, and the increased rigidity can be used in the counter switching direction S' in order to reliably bring the contacts 15 and 16 together or to separate them, and to break open any welds between the contact surfaces 17 and 18.

Fig. 4 shows a schematic side view of a second embodiment of a switching device according to the invention. Unlike the switching device 1, the switching device has a first switching contact assembly 2a and an additional switching contact assembly 2b, which each comprise a switching contact 6' according to the invention, a support 7', and a counter support 21 with corresponding contacts 15' and 17' as well as corresponding electrical connections 19' and counter connections 20'.

A central drive unit 3' of the switching device drives a hinged armature 23' that moves a slider 24'. The slider 24' respectively has a make contact 25' and a break contact 26' for one of the two switching contact assemblies 2a and 2b. In the closed position shown in fig. 4, the slider 24', with the make contact 25', buts the actuation ends 9' of the switching contacts 6' of each of the switching contact assemblies 2' to move the switching contacts 6' in the switching direction S until the contacts 15' of the two switching contact assemblies 2a and 2b abut the corresponding counter contacts 17'.

Fig. 5 shows a schematic perspective view of a second embodiment of a switching device 6' according to the invention. Like the switching contact 6, the switching contact 6' comprises a first spring element 6a' and an additional spring element 6b', which each comprise an attachment section 10', a spring section 11 ', a contact section 12', and an actuation section 13', and, together, form a first switching unit 33a' and an additional switching unit 33b', which are connected via a connection area 34' in the attachment section 10'.

Unlike the switching contact 6, the first spring element 6a' and the second spring element 6b' of the switching contact 6' run on top of one another over substantially the same width as measured in the transverse direction Y. A brace structure 29' in the form of a bend of its edge area 30' running substantially parallel to the longitudinal extension L or central axis M is formed on the first spring element 6a'. In the actuation section 13', the first spring element 6a' is equipped with a weakening structure 36 in the form of a slit running along the actuation section 13' substantially up to the actuation end 9. The weakening structure 36 helps to reduce the rigidity of the first spring element 6a' in the actuation section 13 compared to the rigidity of the additional spring element 6b' in the actuation section 13' or to increase its elasticity.

Fig. 6 shows, in particular, a schematic perspective view of the contact section 12' and the actuation section 13', as well as part of the spring section 11 ' of the switching contact 6a shown in fig. 5. This shows that the two spring elements 6a' and 6b' can be stamped out of sheet metal with substantially the same thickness. When assembled, the spring elements 6a' and 6b' may be formed with the same outer contours and substantially cover one another up to the actuation section 13'. In the actuation section 13', on the other hand, the brace structure 29 or 29' and the weakening structure 36 may contribute to giving the first spring element 6'a less rigidity, at least in the switching direction S, than the additional spring element 6b'.

Fig. 7 shows a third embodiment of a switching contact 6" according to the invention. Like the switching contact 6', the switching contact 6" has an attachment section 10', a spring section 11 ", a contact section 12", an actuation section 13", and forms a first switching unit 33a" and a second switching unit 33b". Unlike the switching contacts 6 and 6', in addition to a first spring element 6a" and a second spring element 6b", the switching contact 6" also comprises an additional spring element 6c", extending from the attachment section 10" beyond the contact section 12" into the actuation section 13". The first spring element 6a" is sandwiched between the additional spring element 6b" and the additional spring element 6c" in this overlapping area. Thus, the spring section 11" of the switching contact 6" has a greater spring stiffness than the spring sections 11 ' and 11" of the switching contacts 6' and 6", as well as two bends 14", which are each formed on the first spring element 6a" and the additional spring element 6c".

Fig. 8 shows, in particular, a schematic perspective view of the actuation section 13" and the contact section 12", as well as part of the spring section 11" of the switching contact 6". This makes clear that the spring elements 6a", 6b", and 6c" may have substantially the same outer contour and cover each other from the attachment section 34" beyond the contact section 12" and into the actuation section 13". The additional spring element 6c" ends substantially slightly above or below the contact section 12" in the height direction Z, such that the first spring element 6a" and the additional spring element 6b" in the actuation section 13", together with the brace structure 29", the weakening structure 36", and the actuation end 9" formed thereon are substantially free. Fig. 9 shows a fourth embodiment of a switching contact 6"' according to the invention. Like the switching contact 6, the switching contact 6"' has an attachment section 10"', a spring section 11"', a contact section 12"', and an actuation section 13"', formed by a first switching spring element 6a'" and a second spring element 6b'". Unlike the switching contacts 6, 6', and 6", the switching contact 6"' has only one switching unit 33"', which holds one contact 17"'.

Deviations from the aforementioned embodiments are possible within the idea of the invention. Thus, a switching device 1, 1' according to the invention may have any number of the switching contact assemblies 2, 2', 2a, 2b, drive systems 3, 3', and actuation systems 4, 4' configured to meet the respective requirements. The housing 5, 5' may be configured to meet the respective requirements in order to contain the switching contact assemblies 2, 2', 2a, 2b, drive systems 3, 3', and actuation systems 4, 4'.

The switching contact assemblies 2, 2', 2a, 2b may have switching contacts 6, 6', 6", 6"' having any number of, e.g., leaf spring-like, spring elements 6a, 6a', 6b, 6b', 6c, 6a'", 6b'", as well as corresponding supports 7, and form attachment ends 8, 8', 8", 8"', actuation ends 9, 9 ^* , 9", 9 ^* ", attachment sections 10, 10 ^* , 10", 10 ^* ", spring sections 11, I T, 11", I T", contact sections 12, 12", 12", 12" ^* , actuation sections 13, 13', 13", 13"', bends 14, 14 ^* , 14", 14"', contacts 15, 15', 15", 15"', and contact surfaces 16, 16', 16", 16"', each configured to meet the respective requirements. Accordingly, the counter contacts 17, 17', 17", 17"' may form counter contact surfaces 18, 18', 18", 18"' meeting the respective requirements. Electrical connections 19, 19', 19", 19"' and counter contacts 20, 20', 20", 20"' may be configured or arranged to meet the respective requirements. Counter supports 21 may be configured according to the respective requirements in order to bear counter contacts 17, 17 ^* , 17", 17" ^* . Free ends 27, 27 ^* , 27", 27 ^*** , 28, 28 ^* , 28", 28 ^*** brace structures 29, 29 ^* , 29", 29"', edge areas 30, 30', 30", 30"', connection means 31, and attachment openings 32 may be present in any number and configured and arranged to meet the respective requirements.

Additionally, a switching contact 6, 6', 6", 6"' according o the invention may form any number of switching units 33a, 33a', 33a", 33b, 33b', 33b", 33"', which may be connected in a connection area 34, 34', 34" and separated by a slit 35, 35', 35". Weakening structures 36, 36', 36" and connection openings 37, 37', 37", 37"' may be configured or arranged to meet the respective requirements. Additionally, any number of hinged armatures 23, 23', sliders 24, 24', make contacts 25, 25', and break contacts 26, 26' may be configured and arranged to meet the respective requirements in order to move the switching device 1, 1' from the open position O into the closed position C and back by generating spring forces F _F , switching forces F _s , counter switching forces Fss resetting forces F _R , and counter resetting forces F _R' of a magnitude respectively meeting the respective requirements in the switching direction S or the counter switching direction S' and transferring them to the switching contact 6, 6', 6", 6"'.

Reference numerals

1, 1 ' Switching device (relay)

2, 2' Switching contact assembly

2a First switching contact assembly

2b Additional switching contact assembly

3, 3' Drive system

4, 4' Actuation system

5, 5' Housing

6, 6', 6" Switching contact

6a, 6a', 6a", 6a'" First spring element

6b, 6b', 6b", 6b' " Additional spring element

6c Additional spring element

7 Support

8, 8', 8", 8"' Attachment end

9, 9', 9", 9"' Actuation end

10, 10', 10", 10"' Attachment section

11, 11 ', 11 ", 11 "' Spring section

12, 12', 12", 12"' Contact section

13, 13', 13", 13"' Actuation section

14, 14', 14", 14"' Bend

15, 15', 15", 15"' Contact

16, 16', 16", 16"' Contact surface

17, 17', 17", 17"' Counter contact

18, 18', 18", 18"' Counter contact surface

19, 19', 19", 19"' Electrical connection

20, 20', 20", 20"' Electrical counter connection

21 Counter support

22a, 22b, 22c Control connections

23, 23' Hinged armature

24, 24' Slider/actuator

25, 25' Make contact

26, 26' Break contact

27, 27', 27", 27"' Free end

28, 28', 28", 28"' Additional free end

29, 29', 29", 29"' Brace structure

30, 30', 30", 30"' Edge area

31 Connection means

32 Attachment opening

33"' Switching unit

33a, 33a', 33a" First switching unit

33b, 33b', 33b" Additional switching unit

34, 34', 34" Connection area

35, 35', 35" Slit

36, 36', 36", 36"' Weakening structure

37, 37', 37", 37"' Connection opening 0 Open position

C Closed position

F _F Spring force

Fs Switching force

Fs- Counter switching force

F _R Resetting force

FR- Counter resetting force

L Longitudinal extension

R Rotational axis

S Switching direction

S' Counter switching direction u Overtravel

w Switching path

X Longitudinal direction

Y Transverse direction z Height direction