GB2562866A

GB2562866A - Contact system and relay having the same

Info

Publication number: GB2562866A
Application number: GB1804939.5A
Authority: GB
Inventors: Herrmann Marcus; Herzog Erik
Original assignee: Johnson Electric SA
Current assignee: Johnson Electric SA
Priority date: 2017-03-29
Filing date: 2018-03-27
Publication date: 2018-11-28
Also published as: DE102017106773B4; FR3064814A1; DE102017106773A1; GB201804939D0; BR102018006280A2; CN108695114A

Abstract

A contact system 1 includes at least one contact pair 5, 6 and a flexible contact support 2. The contact pair includes a fixed contact piece 5 connected to a first conductor rail 7 and a moveable contact piece 6. The flexible contact support includes first and second spring limbs 3.1, 3.2 connected to each other via a connection 4. An end of the first spring limb connected to a second conductor rail 8 and the moveable contact piece attached on the second spring limb. The opposing first and second spring limbs 3.1, 3.2 extending from the connection form a sharp angle V-shaped configuration. The contact support may be formed of a single piece or of a multi-piece design. The contact support may, in the connection area, be formed of two spring limbs arranged in parallel above one another and connected to each other (see fig. 1B).

Description

(71) Applicant(s):

Johnson Electric S.A.

Freiburgstrasse 33, Murten CH-3280, Switzerland (72) Inventor(s):

Marcus Herrmann

Erik Herzog (74) Agent and/or Address for Service:

Albright IP Limited

County House, Bayshill Road, CHELTENHAM, Gloucestershire, GL50 3BA, United Kingdom (51) INT CL:

H01H 1/26 (2006.01) (56) Documents Cited:

GB 2511569 A

GB 1202251 A

SU 001372410 A1

US 6246306 B1

US 3211874 A

H01H 50/56 (2006.01)

GB 1571589 A EP 0837482 A2

US 6252478 B1

US 3376526 A (58) Field of Search:

INT CL H01H

Other: EPODOC, WPI, Patent Fulltext (54) Title ofthe Invention: Contact system and relay having the same Abstract Title: Contact system having a V-shaped flexible contact support (57) A contact system 1 includes at least one contact pair 5, 6 and a flexible contact support 2. The contact pair includes a fixed contact piece 5 connected to a first conductor rail 7 and a moveable contact piece 6. The flexible contact support includes first and second spring limbs 3.1, 3.2 connected to each other via a connection 4. An end ofthe first spring limb connected to a second conductor rail 8 and the moveable contact piece attached on the second spring limb. The opposing first and second spring limbs 3.1,3.2 extending from the connection form a sharp angle V-shaped configuration. The contact support may be formed of a single piece or of a multi-piece design. The contact support may, in the connection area, be formed of two spring limbs arranged in parallel above one another and connected to each other (see fig. 1B).

FIG. 1A

1/11

FIG. ΙΑ

2/11

FIG. IB

3/11

FIG. IC

4/} j

5/11

FIG. 2A

6/11

FIG. 2B

7/11

FIG. 2C

8/11

«G. 2D

9/11

FIG. 3A

10/11

FIG. 3B

11/11

FIG. 3C

CONTACT SYSTEM AND RELAY HAVING THE SAME

TECHNICAL FIELD [0001] The present disclosure relates to a contact system and a relay having the same; in particular to a contact system for a switching function in a cut-off relay.

BACKGROUND [0002] Flexible contact supports are particular used in relays for electricity meters (SmartMeter). Cut-off relays comprise one or more contact pairs in which, in each case, one contact is arranged fixed in the relay housing and the other contact is arranged so as to be moveable, for a switching function. Each contact pair is pressed together with a contact force achieved in part through the prestressing of the flexible contact support relative to the relay housing.

[0003] In particular for switching large currents, since the contacts do not touch each other across their whole surface, the current does not flow uniformly across the contact surface but rather must flow through a narrow section at a particular point. As a result of the opposing current directions, i.e. towards the narrow section on one contact and away from the narrow section on the other contact, repulsive magnetic fields are generated. If the electric current is large enough, then there may be a spontaneous lifting of the contacts, igniting an electric arc. As a result, the material heats up intensely at the points of high current density, and depending on the current strength and the duration of the effect there may be contact welding and thereby an unwanted substance-to-substance bond.

[0004] The present invention aims to provide a contact system for a switching function in a cut-off relay which is easy to produce and with which the contact welding can be even more heavily reduced compared with known contact systems.

BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1A illustrates a contact system in accordance with some embodiments, with one-piece and multi-layer contact support.

[0006] FIG. IB illustrates a contact system in accordance with some embodiments, with

-1two-piece and multi-layer contact support.

[0007] FIG. 1C illustrates a contact system in accordance with some embodiments, with one-piece, single-layer contact support.

[0008] FIG. ID illustrates a contact system in accordance with some embodiments, with one-piece, single-layer contact support with a hollow cylindrical connection.

[0009] FIG. 2A-2D illustrate a contact system in accordance with some embodiments, with two one-piece, multi-layer contact supports with a stiffening element.

[0010] FIG. 3A-3C illustrate a contact system in accordance with some embodiments, with two one-piece, multi-layer contact supports with an alternative stiffening element.

[0011] The following implementations are used for the description of the present disclosure in conjunction with above FIGs.

DETAILED DESCRIPTION OF THE EMBODIMENTS [0012] Hereinafter technical solutions in embodiments of the present disclosure are described clearly and completely in conjunction with the drawings in embodiments of the present disclosure. Apparently, the described embodiments are only some rather than all of the embodiments of the present disclosure. Any other embodiments obtained based on the embodiments of the present disclosure by those skilled in the art without any creative work fall within the scope of protection of the present disclosure. It is understood that, the drawings are only intended to provide reference and illustration, and not to limit the present disclosure. The connections in the drawings are only intended for the clearance of description, and not to limit the type of connections.

[0013] It should be noted that, if a component is described to be connected to another component, it may be connected to another component directly, or there may be an intervening component simultaneously. All the technical and scientific terms in the present disclosure have the same definitions as the general understanding of those skilled in the art, unless otherwise defined. Herein the terms in the present disclosure are only intended to describe embodiments, and not to limit the present disclosure.

[0014] FIG. 1A shows a contact system 1 of a relay, the contact system 1 uses a

-2configuration of an essentially V-shaped contact support 2. In at least one embodiment, the relay may be a switch-off relay. The V-shaped contact support 2 comprises two spring limbs

3.1, 3.2 arranged on top of one another and connected to each other, a first, upper spring limb 3.1 and a second, lower spring limb 3.2. The two spring limbs 3.1, 3.2 are connected to one another by a rounded connection 4.

[0015] The contact system 1 switches a contact between a first, stationary, fixed contact piece 5 and a second, moveable contact piece 6. Underneath the second, lower spring limb

3.2, the moveable contact piece 6 is arranged on it in an area of the spring limb end 3.2a. For counterpart, the fixed contact piece 5 is connected to a first component 7 fixed in relation to the relay housing in a conductive manner. The moveable contact piece 6 acts together with the fixed contact piece 5 in such a way that the contact system 1 can be used for switching an electrical circuit. In at least one embodiment, the relay comprises an armature and at least one energizing coil, the energizing coil brings a force owing to the magnetic field generated by it, the armature is configured to act on the contact system for switching upon the force generated by the energizing coil.

[0016] In at least one embodiment, the contact pieces 5, 6 are configured for the electrical circuit between the two components 7, 8 fixed in relation to the relay housing, which are also termed the lower and upper conductor rails, to be interrupted or closed. The two conductor rails 7, 8 are installed fixed in relation to the relay housing in the cut-off relay. On the upper side of the upper conductor rail 8, the contact support 2 is firmly attached with a spring limb end 3.1a of the upper spring limb 3.1 to the upper conductor rail 8 and connected to this in a conductive manner. The fixed contact piece 5 is arranged directly on the upper side of the lower conductor rail 7 and connected to this in a conductive manner.

[0017] In at least one embodiment, the contact support 2 of the contact system 1 is designed as one piece. A sharp angle is formed between the spring limbs 3.1, 3.2. The position of the spring limbs 3.1, 3.2 in relation to one another is V-shaped. As a result, the distance between the spring limbs 3.1, 3.2 near to the rounded connection 4 is very small. This small distance ensures that certain electromagnetic effects have a strong influence. In the event of a flow of current through the contact support 2 to the moveable contact 6 and then to the fixed contact 5, current flows in opposing directions in the two spring limbs 3.1, 3.2. The resulting magnetic field causes, between the two spring limbs 3.1, 3.2, a repulsive force that is

-3dependent on distance. The smaller the distance of the spring limbs 3.1, 3.2 from one another, the larger the repulsive force.

[0018] Since the upper spring limb 3.1 is firmly connected to the upper conductor rail 8, the moveable spring limb 3.2 is repulsed by the first spring limb 3.1 and pressed downwards. This results in a force effect on the moveable contact piece 6, which additionally presses the moveable contact piece 6 onto the fixed contact piece 5. This force effect is stronger in the event of a larger current flowing through the contact support 2. Because of this, this force, particularly in the case of failure, where in the event of a short circuit currents of over 4 kA can flow, is crucial and therefore makes an advantageous contribution to the moveable contact piece 6 not lifting away from the fixed contact piece 5 due to the lifting force. The flexible contact support 2, with the V-shaped alignment of the spring limbs 3.1; 3.2, is designed in such a way that the sum of the contact force from the spring prestress and the magnetic repulsive force from the contact support 2 is greater than the lifting force.

[0019] In at least one embodiment, the contact support 2 shown here has a multi-layer design. The multi-layer design opens up the possibility of using different materials for the various parallel layers, as a result of which an impact on the mechanical and electrical properties of the contact support 2 can be achieved. Through the use of certain materials, the springiness properties can be optimally set. In addition, it is possible to vary the conductivity according to different materials selected. Furthermore, the distances present between the individual layers of the contact support 2 are beneficial for efficient heat dissipation.

[0020] Fig. fB shows a multi-piece, multi-layer embodiment of the contact support 2 of the contact system 1. In at least one embodiment, the contact support 2 is designed as two individual parts in multiple pieces. The first part comprises the upper spring limb 3.1, which is attached with its spring limb end 3.1a to the lower side of the upper conductor rail 8. At the other end, the lower spring limb 3.2 is arranged underneath the upper spring limb 3.1. This forms the second part of the multi-piece contact support 2. In connection 4‘, the two spring limbs 3.1, 3.2 are arranged in parallel above one another and connected to each other in a conductive manner. Here the two areas of the spring limbs 3.1; 3.2, aligned in a V-shape in relation to one another, meet one another in the connection 4‘ in the vertex forming the sharp angle. The connection 4‘ is not rounded at this vertex. Beneath the second, lower spring

-4limb 3.2, the moveable contact piece 6 is arranged on the area of the spring limb end 3.2a. Its counterpart, the fixed contact piece 5, is connected to the first component 7, fixed in relation to the relay housing, of the lower conductor rail 7.

[0021] Further embodiments of the contact supports 2 for contact systems 1 of the cut-off relay are designed as one piece and formed only by a single layer are shown in Fig. IC and Fig. ID.

[0022] The contact support 2 in accordance with Fig. IC is arranged beneath the upper conductor rail 8. The connection 4 of the spring limbs 3.1, 3.2 is designed rounded in this variant.

[0023] In the alternative variant of the contact system 1, which is shown in Fig. ID, the connection 4“ of the contact support 2 has an essentially hollow cylindrical design with a circular base. In at least one embodiment, a small opening of the circle or on the wall of the essentially hollow cylindrical connection area 4“ forms the smallest distance between the opposing spring limbs 3.1; 3.2. In this embodiment, the flexible contact support 2 therefore contains a short area in which the value of the distance between opposing inner walls of the contact support 4, namely the diameter of the hollow cylindrical connection 4“ is not less than the value of the maximum distance between the spring limb ends 3.1a, 3.2a. The distance between the spring limb ends 3.1a, 3.2a refers to the distance between a point on the position of the moveable contact piece 6 on the spring limb 3.2 and a point on the position of the spring limb end 3.1a of the spring limb 3.1 on the second fixed component 8. Wherein the two points each have the same distance from the opening in the wall of the hollow cylindrical connection 4“.

[0024] In Figures 2A, 2B, 2C and 2D and also in Figures 3A, 3B and 3C, two different embodiments of a stiffening element 9 in conjunction with two parallel one-piece contact supports 2 are shown in different views. The contact system f is in each case shown without the fixed first component and the fixed contact piece. In this embodiment, the stiffening element 9 is made of diamagnetic or paramagnetic material arranged on the two parallel one-piece contact supports 2 with a multi-layer design. Here the stiffening element 9 surrounds at least one of the two spring limbs 3.1, 3.2 at least partially. The stiffening element 9 surrounds the spring limbs 3.1, 3.2 in a form-fit manner, whereby a certain clearance S exists between the spring limb 3.1, 3.2 and the stiffening element 9. The range

-5of motion for the deflection of the spring limb 3.1, 3.2 is limited by the amount of the clearance S and hence the increase in distance between the spring limbs 3.1, 3.2 is restricted.

[0025] The amount of clearance S is designed such that the spring constant of the flexible contact support 2 is not influenced during the opening or closing of the contacts during normal operation. In the case of electrical failure, the deflection caused by the residual current and hence the maximum distance between the spring limbs 3.1, 3.2 is limited. As a result, in the event of a deflection of the spring limb 3.1, 3.2, the spring constant increases to greater than the amount of the clearance S. Thus, in the case of small spring constants, large forces can be transferred under the conditions stated.

[0026] The embodiment of the stiffening element 9 which is shown in Figures 2A, 2B, 2C and 2D is shaped in such a way that it can connect two parallel one-piece contact supports 2 arranged next to one another, which are designed as one-piece and multi-layer and on each of which is arranged a moveable contact piece 6, if it is pushed onto the two contact supports 2. This stiffening element 9 mainly comprises a plate, which is bordered on two opposing edges by curved sections. The two opposing sides are designed curved in such a way that the stiffening element 9, when pushed onto the contact supports 2, surrounds those two sides of the contact support 2 which face away from the other respective contact support 2.

[0027] In at least one embodiment, the two contact supports 2 comprise, in each case, a first and a second spring limb 3.1, 3.2 which are connected via a U-shaped connection 4. The second spring limb 3.2 is connected to the second component 8 fixed in relation to the relay housing. The stiffening element 9 is pushed over both the two spring limbs 3.2 of the contact support 2 and hence the deflection of the second spring limbs 3.2 is limited in such a way that the maximum distance between the first spring limbs 3.1 and the second spring limbs 3.2 is limited. In addition, in at least one embodiment, the stiffening element 9 has several openings 10 with curved hooks 11 arranged therein for fixing the stiffening element 9 on the sides of the two contact supports 2 that are facing each other.

[0028] In Fig. 2A, the two moveable contact pieces 6 and the stiffening element 9 are shown, unmounted, in the form of an exploded drawing, next to the two parallel contact supports 2 with, in at least one embodiment, a passage opening 12 in the end area of the two spring limbs 3.2. In Fig. 2B the stiffening element 9 has been pushed onto the two parallel contact supports 2 and the two moveable contact pieces 6 have been fixed in the passage

-6openings 12 of the contact supports 2 shown in Fig. 2A. Fig. 2C shows the contact supports 2 with mounted stiffening element 9 and mounted moveable contact pieces 6 from a sideways perspective. The stiffening element 9 is attached to the second spring limb 3.2, on which the moveable contact piece 6 is also arranged. The second spring limb 3.2 is connected via a rounded connection 4 to the first spring limb 3.1 which is attached to the upper conductor rail

8.

[0029] The section plane A-A labelled therein is shown in Fig. 2D. Fig. 2D shows that the outer ends of the stiffening element 9 surround the second spring limbs 3.2 of the two parallel contact supports 2. Furthermore, the stiffening element 9 is fixed to the contact supports 2 by means of the curved hooks 11. The hooks 11 are shaped in such a way that they enclose the sides of the second spring limbs 3.2 that are facing each other and hence stabilise the system composed of stiffening element 9 and the two contact supports 2. Beneath the plate of the stiffening element 9 and above the contact supports 2 a certain clearance S is present. Beneath the stiffening element 9, the first spring limbs 3.1 of the two contact supports 2 are depicted in this view.

[0030] An alternative variant of a stiffening element 9 is shown in Figures 3A, 3B and 3C. The bar-shaped stiffening element 9 is also suitable for connecting and stiffening two parallel one-piece contact supports 2, so that the deflection of the spring limbs and hence the distance between the first and second spring limbs is limited. In this variant, a certain clearance S also remains between the stiffening element 9 and the contact support 2. Fig. 3 A shows both contact supports 2, each of which have a first and a second spring limb 3.1; 3.2, alongside the moveable contact pieces 6 and the stiffening element 9. The second spring limbs 3.2 each have a passage opening 12, to which the moveable contact pieces 6 can be attached. The stiffening element 9 comprises two parallel, plate-shaped elements which are connected via a central strip continuous along the length of the two plate-shaped elements. The stiffening element 9 is pushed between the two parallel second spring limbs 3.2 for the stiffening of the contact supports 2.

[0031] The mounted state is shown in Fig. 3B. The ends of the first spring limbs 3.1 of the contact supports 2 are connected to a second current-carrying component 8 fixed in relation to the relay housing and the ends of the second spring limbs 3.2 are connected to each other via the bar-shaped stiffening element 9 in such a way that the deflection of the second spring

-7limbs 3.2 is limited. Above the second spring limbs 3.2 the upper plate-shaped element 13 of the stiffening element 9 is depicted and on the longitudinal end, moreover, the strip 15 for the connection of the upper plate-shaped element 13 with the lower plate-shaped element (not shown here). In the view from the side, as depicted in Fig. 3C, above the second spring limbs 3.2 of the contact supports 2 the upper plate-shaped element 13 is shown and below the lower plate-shaped element 14 is shown. Between the upper plate-shaped element 13 and the upper side of the second spring limb 3.2, a distance S is shown which corresponds to the clearance S between the stiffening element 9 and the contact support 2.

[0032] Usually, the relationship between the residual current and the lifting force of the contacts can, as below, be described by Equation I: f^

[0033] Wherein FA is the lifting force, R the radius of a circular contact piece, r the radius of the narrow section, FK the contact force, H the hardness of the contact material and ξ the coefficient of the surface finish. In general, it is true for cut-off relays that the contact force resulting from the spring prestress is smaller than the lifting force.

[0034] According to the invention, the flexible contact support with the V-shaped alignment of the spring limbs is designed in such a way that the sum of the contact force from the spring prestress and the magnetic repulsive force from the contact support is larger than the lifting force. As a result, the lifting of the moveable second contact piece from the contact support attached to the first, fixed, current-carrying component is prevented and the contact welding massively reduced compared with the prior art, since the surface pressure in the contact point, known as Hertzian stress, and the electrical cross sectional area available in the contact point increase, whilst the local current density decreases, which massively reduces the heating-up of the contact material in the contact point beyond the latter’s melting point. Herztian stress should be generally understood to mean the greatest mechanical tension prevailing in the centre of the contact area between two elastic bodies.

[0035] The repulsive force, as already mentioned, results from the interaction between the contact support and the magnetic field surrounding the contact support which is generated by the residual current. The general relationship between repulsive force, residual current (here Ii=l2=residual current) and distance r of the conductor nieces standardised to length L can, as i- !-E; Εύ_ί-, N 1 /}/·;

below, be described with Equation II: 7 - ..... ~p·’¹¹ ’ ””F | [0036] Over and above this, a general relationship exists between contact force and

-8Hertzian stress which can be described with Equation III, where F is the force between the bodies, E is the modulus of elasticity of the materials, El the modulus of elasticity of the first body, E2 the modulus of elasticity of the second body and v the Poisson’s ratio.

[0037]

Equation III: « ~..A.

[0038] [0039]

The following is valid for r and E, as shown in Equations IV and V: ? 'F, i

Equations IV:

[0040]

Equations V: £

[0041] The maximum distance of the spring limbs from one another preferably lies in the area of the ends of the spring limbs, more precisely between the position of the moveable contact piece on the second spring limb and the position of the second fixed component on the first spring limb. The distance between the spring limbs refers to the length between two points arranged on the opposing spring limbs which have the same distance from the connection point or vertex of the two spring limbs on the connection area of the V-shaped contact support. In accordance with a particularly preferred embodiment of the invention, the maximum distance between the spring limbs when the contact support is installed within the cut-off relay corresponds to the distance between the opened contact pieces in an opened state.

[0042] The contact support may be designed as one piece. This means that both spring limbs are formed by the same part. Alternatively, the contact support may also be designed as several parts. This means that the two opposing spring limbs are not formed by the same but by different parts.

[0043] The spring limbs of the contact support may have both a single-layer construction,

i.e. consisting of only one layer, and a multi-layer construction, i.e. each consisting of several parallel layers.

[0044] In other embodiment, the contact support may also be shell-like in shape, with surface elements curved once and/or twice, or be constructed in the manner of a solid body.

[0045] In accordance with a further embodiment of the invention, the contact support is designed in such a way that its geometrical moment of inertia varies along the length of the contact support.

[0046] In accordance with a further advantageous embodiment, the flexible contact support contains, compared with the total length of the contact support, short areas of up to a fifth of the total length of the contact support, in which the value of the distance between opposing inner walls of the contact support exceeds the value of the distance between the spring limb ends.

[0047] In accordance with a further embodiment of the invention, a stiffening element with diamagnetic or paramagnetic material properties is provided which at least partially surrounds at least one of the spring limbs of the flexible contact support in such a way that the range of motion for the deflection of the spring limb and hence the maximum distance between the spring limbs is limited. Through such a diamagnetic or paramagnetic stiffening element for limitation of the maximum distance between the spring limbs, an increase in the repulsive forces between the spring limbs can be achieved. Since there is a certain clearance between the spring limbs and the stiffening element, the spring constant of the flexible contact support is, advantageously, not influenced during the opening and closing of the contacts during normal operation. In the case of electrical failure, the deflection caused by the residual current and hence the maximum distance between the spring limbs is limited, however. As a result, the spring constant increases in the case of a deflection of the spring limb that is so large that it is greater than the clearance. Thus, with small spring constants, large forces can be transferred under the conditions stated.

[0048] A further aspect of the invention relates to a cut-off relay which comprises the contact system according to the invention.

[0049] In a preferred variant, the cut-off relay has an armature in addition to the contact system which is mechanically linked to the moveable contact support in such a way that a movement of the armature is transferred to the contact support. Hence the contact is switched by means of a mechanical movement of the moveable or flexible contact support, whereby the moveable contact piece is moved away from the fixed contact piece or towards the fixed contact piece. The movement of the armature hence switches the contact between the two current-carrying components of the contact system. The armature is a component of an actuator assembly, which comprises at least one exciter coil. Owing to a magnetic field generated by the exciter coil, a force is exerted on a magnetic component which is mechanically linked to the armature in such a way that the force generated on the basis of the

-10magnetic field leads directly to a movement of the armature and hence to a movement of the flexible contact support, which directly gives rise to the switching of the contact between the current-carrying components by means of the contact piece pair.

[0050] Described above are preferable embodiments of the present disclosure, which are 5 not intended to limit the present disclosure. All the modifications, equivalent replacements and improvements in the scope of the spirit and principles of the present disclosure are in the protection scope of the present disclosure.

Claims

1. A contact system, comprising:

at least one contact pair, the contact pair comprising a fixed contact piece connected to a first conductor rail and a moveable contact piece together with the fixed contact piece for switching function; and a flexible contact support comprising a first and a second spring limbs connected to each other via a connection, an end of the first spring limb connected to a second conductor rail and the moveable contact piece attached on the second spring limb;

wherein the opposing first and second spring limbs extending from the connection form a sharp angle V-shaped configuration.

2. The contact system of claim 1, wherein the maximum distance of the spring limbs from one another lies in the area of ends of the spring limbs.

3. The contact system of claim 1, wherein the contact support is designed as comprising at least one one-piece.

4. The contact system of claim 1, wherein the contact support is formed by a multi-piece design.

5. The contact system of claim 4, wherein in the connection area, the two spring limbs are arranged in parallel above one another and connected to each other conductively.

6. The contact system of claim 1, wherein the spring limbs of the contact support are each constructed from several parallel layers.

7. The contact system of claim 6, wherein the contact support is designed by different materials for the various parallel layers to impact on the mechanical and electrical properties of the contact support.

8. The contact system of claim 1, wherein the spring limbs of the contact support are each constructed from only one layer.

9. The contact system of claim 1, wherein the connection is designed as a rounded shape.

10. The contact system of claim 1, wherein the connection is designed as an essentially hollow cylindrical shape.

11. The contact system of claim 10, wherein an opening of the essentially hollow cylindrical connection forms the smallest distance between the opposing spring limbs.

12. The contact system of claim 1, further comprising a stiffening element in conjunction with two parallel one-piece contact supports, wherein the stiffening element is configured to limit of the deflection caused by the residual current and maximum distance between the spring limbs.

f3. The contact system of claim 12, wherein the stiffening element is made of diamagnetic or paramagnetic material arranged on the two parallel one-piece contact supports.

f4. The contact system of claim 12, wherein the stiffening element is surrounds at least one of the two spring limbs at least partially and a certain clearance exists between the spring limb and the stiffening element.

f5. The contact system of claim 12, wherein the stiffening element mainly comprises a plate, which is bordered on two opposing edges by curved sections.

f6. The contact system of claim 12, wherein the stiffening element comprises two parallel, plate-shaped elements which are connected via a central strip continuous along the length of the two plate-shaped elements.

17. A relay, comprising the contact system according to any one of claims 1 to 16.

18. The relay of claim 17, wherein the relay is a switch-off relay.

19. The relay of claim 17, wherein the first and the second conductor rails are fixed in relation to the relay housing.

20. The relay of claim 17, further comprising an armature and at least one energizing coil, wherein the armature is configured to act on the contact system for switching by a force generated by the energizing coil.

-1314

Intellectual

Property

Office

Application No: GB1804939.5