contact assembly

Abstract

A contact assembly for an electrical circuit breaker, a circuit maker or an electrical switch, the contact assembly comprising a first contact member electrically connected to a first electrical terminal, a second contact member electrically connected to a second electrical terminal (5), and a third contact member movable to contact and disengage from the second contact member. A fourth contact member elastically deformable ensures electrical contact between the first contact member and the second contact member, and the contact assembly is configured such that when the third contact member is moved along towards the second contact member, the fourth contact member is progressively compressed between the first contact member and a respective abutment surface of the third contact member, thereby elastically deforming the fourth contact member. Furthermore, an electrical circuit breaker and an electrical switch, respectively comprising such a contact assembly. Furthermore, a vacuum interrupter comprising such an electrical circuit breaker.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a contact assembly for an electrical circuit breaker or electrical switch. BACKGROUND

[0002] Electrical circuit breakers, such as vacuum circuit breakers, generally comprise electrical contacts, at least one of which is movable relative to the other to open and close a gap, thereby making or breaking an electrical contact. Each movable electrical contact is typically electrically connected to a respective electrical terminal fixed to a frame or housing of the electrical circuit breaker, and the electrical connection between the movable electrical contact and the fixed terminal is enabled using a flexible cable terminated with a cable lug fixed to the electrical terminal or frame using a nut, washer and / or bolt. The use of such a cable introduces a number of components required for the electrical circuit breaker. Furthermore, over time, the cable tends to wear and break, resulting in contamination of surrounding electrical components, ultimately leading to failure of the electrical circuit breaker.

[0003] US4052577 relates to a magnetically driven ring arc runner for a circuit interrupter. This device is complex.

[0004] It is therefore an object of the present disclosure to provide an improved contact assembly for an electrical switch or electrical circuit breaker, enabling a compact design with fewer components, reduced wear and tear and lower risk of failure. SUMMARY

[0005] According to a first aspect of the present disclosure, the object and other objects are achieved by a contact assembly defined in the independent claim 1 below. Alternative embodiments are defined in the dependent claims.

[0006] The contact assembly comprises a first contact member electrically connected to a first electrical terminal by a cable, by the first contact member being integrally formed with the first electrical terminal, or by the first contact member being directly connected to the first electrical terminal. The contact assembly further comprises a second contact member electrically connected to a second electrical terminal. The contact assembly further comprises a third contact member guided to move along a first longitudinal axis at least between a first contact position, in which the third contact member physically contacts the second contact member, and a non-contact position, in which the third contact member is physically separated from the second contact member, the movement being achieved by the third contact member moving a first predetermined distance along the first longitudinal axis away from the first contact position. The contact assembly further comprises a fourth contact member, which is elastically deformable and electrically conductive, the fourth contact member being arranged between a first abutment surface of the first contact member and a second abutment surface of the third contact member.

[0007] The first and second abutment surfaces are configured such that the distance between the first and second abutment surfaces increases when the third contact member is moved in a direction along the first longitudinal axis away from the second contact member and such that the distance between the first and second abutment surfaces decreases when the third contact member is moved in a direction towards the second contact member. Further, the fourth contact member is configured such that it physically contacts the first and second abutment surfaces at least when the third contact member is in the first contact position.

[0008] The second and third contact members are movable relative to each other to make or break electrical contact between each other depending on their relative position. The relative movement between the second and third contact members is achieved by the movability of the third contact member along the first longitudinal axis. The electrical contact between the first electrical terminal and the third contact member is established by the first and fourth contact members. By configuring the first abutment surface of the first contact member and the second abutment surface of the third contact member such that the distance between them changes with movement of the third contact member, the electrical contact between the first and second abutment surfaces can be established by different degrees of compression of the elastically deformable fourth contact member, substantially without the need for a sliding movement between the fourth contact member and the respective abutment surface. By mitigating the sliding between the fourth contact member and the abutment surfaces, the wear of the contact assembly is reduced. Further, the dimensions of the contact members can be reduced to only fill the gap required between the first and second abutment surfaces, thereby enabling electrical isolation between the second and third contact members when the third contact member is in its non-contact position. This enables a compact design of the contact assembly, thereby enabling a compact design of a circuit breaker or switch using the contact assembly.

[0009] The third contact member can comprise a protrusion surrounded by a circumferential shelf forming the second abutment surface, wherein the fourth contact member is a ring arranged around the protrusion.

[0010] When the ring is biased between the first and third contact members, the ring rests on the circumferential shelf and the fourth contact member provided in the form of a ring around the protrusion provides for an improved positioning of the fourth contact member as well as a uniform loading and deformation of the contact members when the third contact member is moved relative to the first contact member.

[0011] The ring can be a closed ring.

[0012] Although the ring can be formed with a gap, i.e. not be a closed ring, it is advantageous to provide a closed ring as it improves the distribution of forces around the ring when the ring is compressed and facilitates a uniform deformation of the ring, thereby correspondingly reducing the tendency for sliding between the ring and the first and second abutment surfaces as the closed ring has no free end.

[0013] The ring can comprise a helical spring. Providing the ring in the form of a helical spring correspondingly provides a large number of contact points or contact areas between the ring and the first and second abutment surfaces. Providing more contact points / contact areas reduces the risk of poor electrical contact and reduces the risk of local electrical arcing, thereby reducing wear and contamination of the contact assembly.

[0014] Although helical springs are widely used to provide elasticity along the longitudinal extent of the helical spring, it should be understood that the "helical spring" referred to herein is designed to be compressible transverse to the longitudinal extent of the helical spring. In fact, the term "helical spring" can also be replaced by the term "resilient member comprising a wire that is wound to form a plurality of coils around a central path of the resilient member". The wire is wound similarly to the helical coils of a standard helical spring, but the cross-sectional shape of each coil can vary, for example as Fig. 6-9 indicated.

[0015] The helical spring can comprise a wire that is wound into coils such that the cross-section of the helical spring has a first ridge facing the first abutment surface and a second ridge facing the second abutment surface. The first ridge is radially offset from the second ridge with respect to the first longitudinal axis. The radial offset between the first ridge and the second ridge position makes it easier for the fourth contact member to deform due to the increase in momentum on each coil caused by the radial offset.

[0016] The helical spring can comprise a wire that is wound into coils such that the helical spring comprises a generally diamond-shaped cross-sectional shape with rounded corners. The diamond-shaped cross-sectional shape provides a substantially straight portion of the wire of each coil. The substantially straight portion enables a greater contact surface between the abutment surfaces, thus reducing the risk of poor electrical contact and reducing the risk of local electrical arcing, thereby reducing wear and contamination of the contact assembly. The diamond-shaped cross-sectional shape makes it easier for the fourth contact member to deform.

[0017] Each coil can comprise two substantially straight parallel first wire portions and two substantially straight parallel second wire portions that are inclined with respect to the first wire portions, respectively, the first wire portions facing the first and second abutment surfaces.

[0018] The contact assembly can further comprise a fifth contact member electrically connected to a third electrical terminal. The third contact member is movable along the first longitudinal axis from a first contact position through a non-contact position a second predetermined distance to a second contact position, at which the third contact member physically contacts the fifth contact member. The fourth contact member is biased between the first and third contact members throughout the range of movement from the first contact position to the second contact position.

[0019] The first contact member can comprise a cylinder having a central through-hole. Further, the third contact member can comprise a protrusion extending through the central through-hole of the first contact member.

[0020] According to a second aspect of the present disclosure, it is proposed to provide an electrical circuit breaker comprising the above-mentioned contact assembly.

[0021] According to a third aspect of the present disclosure, it is proposed to provide an electrical circuit maker comprising the above-mentioned contact assembly.

[0022] According to a fourth aspect of the present disclosure, it is proposed to provide an electrical switch comprising the above-mentioned contact assembly, the above-mentioned contact assembly comprising a fifth contact member.

[0023] According to a fifth aspect, it is proposed to provide a vacuum interrupter comprising the above-mentioned electrical circuit breaker.

[0024] As will be apparent to any person skilled in the art, the above-mentioned aspects, the following claims and / or examples disclosed in the foregoing and hereinafter can be suitably combined with each other. BRIEF DESCRIPTION OF DRAWINGS

[0025] Fig. 1-3 A cross-sectional schematic view of a first embodiment of a contact assembly according to the present disclosure is shown. In Fig. 1 the contact assembly is in a first contact position having electrical contact between the first electrical terminal and the second electrical terminal. In Fig. 2 the contact assembly is in a non-contact position having no electrical contact between the first electrical terminal and the second electrical terminal. In Fig. 3 the contact assembly is in a second contact position having electrical contact between the first electrical terminal and the third electrical terminal. Thus, Fig. 1-3 An embodiment of a contact assembly useful in an electrical switch is shown. In other embodiments, the third electrical terminal and the fifth contact member can alternatively be omitted, wherein the contact assembly would be useful in an electrical circuit breaker.

[0026] Fig. 4 A cross-sectional schematic view of an alternative embodiment of the contact assembly shown in Fig. 1-3 is shown. This contact assembly is substantially axis-symmetric about the first longitudinal axis, but otherwise corresponds to the contact assembly in Fig. 1-3 .

[0027] Fig. 5 A vacuum interrupter comprising an embodiment of an electrical circuit breaker similar to the electrical circuit breaker portion of the contact assembly in Fig. 2 indicated by the dashed line with reference number 20 in Fig. 1-4 is shown. However, the contact assembly 1 in the vacuum interrupter uses a different third contact member 3 than the contact assembly in Fig. 10The shown embodiment corresponds to a further embodiment of the fourth switching device.

[0028] Fig. 6-9 Schematic drawings showing four different embodiments of the cross-sectional shape of the ring serving as fourth contact member.

[0029] Fig. 10 Particularly shown is a ring having a cross-sectional shape similar to Fig. 8 Different views of a ring having a cross-sectional shape similar to the shown cross-sectional shape. DETAILED DESCRIPTION

[0030] With reference to the appended drawings, below follows a more detailed description of embodiments of the disclosure cited as examples.

[0031] As mentioned above, it is an object of the present disclosure to provide an improved contact assembly 1 for an electrical switch or an electrical circuit breaker, thereby achieving a compact design with fewer components, reduced wear and tear and lower risk of failure.

[0032] This and other objects are achieved by a contact assembly 1 according to the exemplary embodiments described below, and as Fig. 1-3 shown.

[0033] The contact assembly 1 comprises a first contact member 2 electrically connected to a first electrical terminal 3 by a cable, by the first contact member 2 being integrally formed with the first electrical terminal 3, or by the first contact member 2 being directly connected to the first electrical terminal 3. The contact assembly 1 further comprises a second contact member 4 electrically connected to a second electrical terminal 5. The contact assembly 1 further comprises a third contact member 6 guided to move along a first longitudinal axis 7 between at least a first contact position CP1, in which the third contact member 6 physically contacts the second contact member 4, and a non-contact position NCP, in which the third contact member 6 is physically spaced apart from the second contact member 4, by the third contact member 6 moving a first predetermined distance D1 along the first longitudinal axis 7 away from the first contact position CP1. The first predetermined distance D1 should be chosen large enough to provide electrical insulation when the third contact member is in the non-contact position NCP. The contact assembly 1 further comprises a fourth contact member 8 elastically deformable and electrically conductive, which is arranged between a first abutment surface 9 of the first contact member 2 and a second abutment surface 10 of the third contact member 6.

[0034] The first abutment surface 9 and the second abutment surface 10 are configured such that the distance between the first abutment surface 9 and the second abutment surface 10 increases when the third contact member 6 is moved in a direction along the first longitudinal axis 7 away from the second contact member 4 and such that the distance between the first abutment surface 9 and the second abutment surface 10 decreases when the third contact member 6 is moved in a direction towards the second contact member 4. Further, the fourth contact member 8 is configured such that it physically contacts both the first abutment surface 9 and the second abutment surface 10 at least when the third contact member 6 is in the first contact position CP1. The second contact member 4 and the third contact member 6 are movable relative to each other to make or break electrical contact between each other depending on their relative position. The relative movement between the second contact member 4 and the third contact member 6 is enabled by the movability of the third contact member 6 along the first longitudinal axis 7, but in this embodiment the second contact member 4 is stationary. The electrical contact between the first electrical terminal 3 and the third contact member 6 is established by the first contact member 2 and the fourth contact member 8. By configuring the first abutment surface 9 of the first contact member 2 and the second abutment surface 10 of the third contact member 6 such that the distance between them varies with the movement of the third contact member 6, it is possible to establish electrical contact between the first abutment surface 9 and the second abutment surface 10 by means of different degrees of compression of the elastically deformable fourth contact member 8, and substantially without the need for sliding movement between the fourth contact member 8 and the respective abutment surfaces. By reducing the sliding between the fourth contact member 8 and the abutment surfaces, the wear of the contact assembly 1 is reduced. Further, the dimensions of the contact members can be reduced to only fill the gap needed between the first abutment surface 9 and the second abutment surface 10, such that the second contact member 4 and the third contact member 6 can be electrically isolated from each other when the third contact member 6 is in its non-contact position NCP. This makes it possible to design the contact assembly 1 compactly, and thus the circuit breaker or switch in which the contact assembly 1 is used.

[0035] Any suitable electrically conductive material can be used for the fourth contact member 8. Further, any suitable design can be used for the fourth contact member 8, as long as the design provides the required flexibility and elasticity to enable the contact pressure on the first abutment surface 9 and on the second abutment surface 10 to be sufficient to provide good electrical contact between the fourth contact member 8 and the first contact member 2 and the third contact member 6, respectively, while enabling the third contact member 6 to travel at least the first predetermined distance D1. Such a material can be steel, copper or some suitable metal alloy.

[0036] Although the illustrated embodiments also include a fifth contact member 15 and a third terminal 19, enabling the use of the contact assembly in an electrical switch, the fifth contact member 15 and the third electrical terminal 19 can alternatively be omitted in other embodiments discussed herein, if the contact assembly 1 is only used as an electrical circuit breaker.

[0037] The first and second abutment surfaces 9, 10 can have any suitable shape, e.g. planar or curved, as long as the distance D between the first and second abutment surfaces 9, 10 varies as described above. Although the illustrated embodiments have first and second abutment surfaces 9, 10 which are planar and oriented perpendicular to the first longitudinal direction 7, it is understood that the orientation of the first and second abutment surfaces 9, 10 can be varied. For example, the first and second abutment surfaces 9, 10 can be arranged obliquely with respect to the longitudinal axis. However, the abutment surfaces 9, 10 should not be parallel to the first longitudinal axis, as such sliding between the contact member 8 and the respective abutment surface 9, 10 should be avoided in order to mitigate wear of the fourth contact member 8 and the respective abutment surface 9, 10, which would result in contamination by wear particles.

[0038] In some embodiments, e.g. Fig. 4 and Fig. 5 The illustrated embodiments, the third contact member 6 comprises a protrusion 11 surrounded by a circumferential shelf 12 forming the second abutment surface 10, wherein the fourth contact member 8 is a ring arranged around the protrusion 11. Other features of these embodiments are similar to the features of the embodiments of Fig. 1-3 .

[0039] When biased between the first and third contact members 2, 6, the ring rests on the circumferential shelf 12, and the provision of the fourth contact member 8 in the form of a ring around the protrusion 11 provides for improved positioning of the fourth contact member 8 as well as uniform loading and deformation of the contact members when the third contact member 6 is moved relative to the first contact member 2.

[0040] The ring is a closed ring, but can alternatively be replaced by an open ring, i.e. a ring having two free ends and a gap between the free ends, in other embodiments.

[0041] Although the ring can be formed with a gap, i.e. not be a closed ring, it is advantageous to provide a closed ring, as it improves the distribution of forces around the ring when the ring is compressed, and facilitates uniform deformation of the ring, thereby correspondingly reducing the tendency of the ring to slide between the first and second abutment surfaces 10, as the closed ring has no free ends.

[0042] The ring comprises a helical spring.

[0043] Providing the ring in the form of a helical spring accordingly provides a number of contact points or contact areas between the ring and the first and second abutment surfaces 10. Providing more contact points / contact areas reduces the risk of poor electrical contact and reduces the risk of local electrical arcing, thereby reducing wear and contamination of the contact assembly 1.

[0044] The helical spring comprises a wire formed into a coil, such that the helical spring comprises a cross-section having a cross-sectional shape.

[0045] The hollow interior space of the helical spring allows the helical spring to be compressed in a direction normal to a central path along which the helical spring is wound when manufacturing the helical spring. Fig. 10

[0046] The cross-sectional shape of the helical spring can be any suitable shape, and some alternative shapes are shown in Fig. 6-9

[0047] As shown in Fig. 7-10 the cross-sectional shape of the embodiments provides the helical spring with a first ridge 16 facing the first abutment surface 9 and a second ridge 17 facing the second abutment surface.

[0048] The first ridge 16 is radially offset from the aforementioned second ridge 17 with respect to the first longitudinal axis 7.

[0049] The radial offset between the first ridge 16 and the second ridge position makes it easier for the fourth contact member 8 to deform, due to the increased momentum on each coil caused by the radial offset.

[0050] In other words, the helical spring can comprise a wire formed into a coil, such that the helical spring comprises a cross-sectional shape having a substantially rhombic shape with rounded corners. The rhombic cross-sectional shape provides a substantially straight portion of the wire of each coil. The substantially straight portion enables a greater contact surface between the abutment surfaces, thus reducing the risk of poor electrical contact and reducing the risk of local electrical arcing, thereby reducing wear and contamination of the contact assembly 1. The rhombic cross-sectional shape enables the fourth contact member 8 to deform more easily.

[0051] As shown in Fig. 7 each coil can thus comprise two substantially straight parallel first wire portions 13a, 13b, respectively, and two substantially straight parallel second wire portions 14a, 14b, which are inclined with respect to the first wire portions 13a, 13b, the aforementioned first wire portions 13, 13b facing the first abutment surface 9 and the second abutment surface 10.

[0052] ​​If the contact assembly is to be used as an electrical switch 21, the contact assembly 1 can further comprise a fifth contact member 15 electrically connected to the third electrical terminal 19 (see Fig. 1-4 The third contact member 6 is movable along the first longitudinal axis 7 away from the first contact position CP1 by a second predetermined distance D2, past a non-contact position NCP to a second contact position CP2 in which the third contact member 6 physically contacts the fifth contact member 15. The fourth contact member 8 is biased between the first contact member 2 and the third contact member 6 throughout the entire range of movement from the first contact position CP1 to the second contact position CP2.

[0053] As shown in Fig. 4 and Fig. 5 the first contact member 2 can comprise a cylinder having a central through hole 18. As also shown in Fig. 4 and Fig. 5 the third contact member 6 can comprise a protrusion 11 extending through the central through hole 18 of the first contact member 2.

[0054] It is proposed to provide an electrical circuit breaker comprising the above-described contact assembly 1.

[0055] Further, it is proposed to provide an electrical circuit maker comprising the above-described contact assembly 1. Further, it is proposed to provide an electrical switch comprising the above-described contact assembly 1 comprising a fifth contact member 15.

[0056] Further, it is proposed to provide a vacuum interrupter 22 comprising an electrical circuit breaker 20 according to the above-described embodiments of the contact assembly 1. In Fig. 5An exemplary embodiment of such a vacuum interrupter 22 is schematically illustrated in Fig. 1. The vacuum interrupter 22 comprises a housing 24 and the third contact member 6 comprises a portion that extends through an opening of the housing. The vacuum interrupter comprises sealing means (not shown) for a gas-tight seal between the housing 24 and the third contact member 6 such that the vacuum inside the housing 24 can be maintained over time while allowing for movement of the third contact member 6 along the first longitudinal axis 7 to be controlled by an actuator 23 attached to the housing 24 outside of the housing 24. In other embodiments, the actuator can alternatively be provided within the housing 24, wherein the third contact member would not need to extend through an opening of the housing. In another embodiment, the actuator 23 can be omitted, wherein the third contact member 6 is instead manually operated. The first and second electrical terminals 3, 5 are configured such that they are accessible from outside of the housing 24. The first electrical terminal 3 is electrically connected to the first contact member 2 by a cable, but any other means for providing electrical contact between the first contact member 2 and the first electrical terminal 3 can also be used. For example, the first electrical terminal 3 can be integrally formed with or directly attached to the first contact member 2. The first and second contact members 2, 4 are fixed to the housing 24. As discussed above, the fourth member 8 comprises Fig. 10 A helical spring is shown. The helical spring has a cross-sectional shape that provides a first ridge 16 facing the first abutment surface 9 and a second ridge 17 facing the second abutment surface 10. The first ridge 16 is radially offset from the second ridge 17 with respect to the first longitudinal axis 7.

[0057] Legend of the figures

[0058] 1 Contact assembly 2 First contact member 3 First electrical terminal 4 Second contact member 5 Second electrical terminal 6 Third contact member 7 First longitudinal axis 8 Fourth contact member 9 First abutment surface 10 Second abutment surface 11 Protrusion 12 Circumferential shelf 13a, 13b First wire portion 14a, 14b Second wire portion 15 Fifth contact member 16 First ridge 17 Second ridge 18 Central through hole 19 Third electrical terminal 20 Electrical circuit breaker 21 Electrical switch 22 Vacuum circuit breaker 23 Actuator 24 Housing CP1 First contact position CP2 Second contact position D1 First predetermined distance D2 Second predetermined distance NCP Non-contact position

Claims

1. A contact assembly (1) for an electrical circuit breaker, a circuit maker or an electrical switch, the contact assembly (1) comprising: a first contact member (2) electrically connected to a first electrical terminal (3) by a cable, by being integrally formed with the first electrical terminal (3) or by being directly connected to the first electrical terminal (3), a second contact member (4) electrically connected to a second electrical terminal (5), a third contact member (6) guided to move along a first longitudinal axis (7) between at least a first contact position (CP1) in which the third contact member (6) physically contacts the second contact member (4) and a non-contact position (NCP) in which the third contact member (6) is physically separated from the second contact member (4), the movement being achieved by the third contact member (6) moving a first predetermined distance (D1) along the first longitudinal axis (7) away from the first contact position (CP1), the contact assembly (1) further comprising a fourth contact member (8) that is elastically deformable and electrically conductive, the fourth contact member (8) being arranged between a first abutment surface (9) of the first contact member (2) and a second abutment surface (10) of the third contact member (6), wherein the first abutment surface (9) and the second abutment surface (10) are configured such that the distance (D) between the first abutment surface (9) and the second abutment surface (10) increases when the third contact member (6) moves away from the second contact member (4) in a direction along the first longitudinal axis (7) and such that the distance (D) between the first abutment surface (9) and the second abutment surface (10) decreases when the third contact member (6) moves in a direction towards the second contact member (4), and wherein the fourth contact member (8) is configured such that it physically contacts the first abutment surface (9) and the second abutment surface (10) at least when the third contact member (6) is in the first contact position (CP1).

2. The contact assembly (1) according to claim 1, wherein the third contact member (6) comprises a protrusion (11) surrounded by a circumferential shelf (12) forming the second abutment surface (10), wherein the fourth contact member (8) is a ring arranged around the protrusion (11).

3. The contact assembly (1) according to claim 2, wherein the ring is a closed ring.

4. The contact assembly (1) according to any one of claims 2 and 3, wherein, the ring comprises a helical spring.

5. The contact assembly (1) according to claim 4, wherein the helical spring comprises a wire formed into a coil such that a cross-section of the helical spring has a first ridge (16) facing the first abutment surface (9) and a second ridge (17) facing the second abutment surface (10), the first ridge (16) being radially offset from the second ridge (17) with respect to the first longitudinal axis (7).

6. The contact assembly (1) according to claim 4, wherein The helical spring comprises a wire formed being wound into coils such that the helical spring comprises a substantially rhombic cross-sectional shape with rounded corners.

7. The contact assembly (1) according to claim 4, wherein The helical spring comprises a wire formed being wound into coils, and wherein each coil comprises two substantially straight parallel first wire portions (13a, 13b) and two substantially straight parallel second wire portions (14a, 14b) inclined with respect to the first wire portions (13a, 13b), the first wire portions (13a, 13b) facing the first abutment surface (9) and the second abutment surface (10), respectively.

8. The contact assembly (1) according to any one of claims 1 to 3, further comprising a fifth contact member (15) electrically connected to a third electrical terminal (19), wherein, The third contact member (6) is movable along the first longitudinal axis (7) from the first contact position (CP1), through the non-contact position (NCP) a second predetermined distance (D2) to a second contact position (CP2) in which the third contact member (6) physically contacts the fifth contact member (15), The fourth contact member (8) is biased between the first contact member (2) and the third contact member (6) throughout the range of movement from the first contact position (CP1) to the second contact position (CP2).

9. The contact assembly (1) according to claim 8, wherein The first contact member (2) comprises a cylinder with a central through hole (18), and wherein the third contact member (6) comprises a protrusion (11) extending through the central through hole (18) of the first contact member (2).

10. An electric appliance switch (20) comprising the contact assembly (1) according to claim 8 or 9.

11. An electrical circuit breaker (21) comprising the contact assembly (1) according to any one of claims 1 to 9.

12. An electrical circuit maker comprising the contact assembly (1) according to any one of claims 1 to 9.

13. A vacuum interrupter comprising the electrical circuit breaker according to claim 11.

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