WO2009105915A1

WO2009105915A1 - Switch device, method of assembling or operating it

Info

Publication number: WO2009105915A1
Application number: PCT/CN2008/000413
Authority: WO
Inventors: Frank Kalvelage
Original assignee: Siemens Aktiengesellschaft
Priority date: 2008-02-29
Filing date: 2008-02-29
Publication date: 2009-09-03

Abstract

A switching device ( 10 ) comprises at least one first contact member ( 14 ) being moveable relative to at least one second contact member ( 16 ) to reversibly electrically contact the at least one second contact member ( 16 ), wherein the at least one first contact member ( 14 ) is connected with and moveable by at least one electromechanical actuating means ( 18 ). A method of assembling or operating such a switching device ( 10 ).

Description

Switching device, method of assembling or operating such switching device and electrical device comprising such switching device

The present invention relates to a switching device comprising at least one first contact member being moveable relative to at least one second contact member to reversibly contact the second contact member electrically conducting and to a method of operating such a switching device. Furthermore, the present invention relates to a method of operating such a switching device and to an electrical circuit and an electrical device comprising at least one such switching device.

Switching devices such as contactors or relays are generally known and are generally electromagnetically actuated or, in rarer cases, gas pressure actuated.

In electromagnetic relays, an electromagnetic actuator comprises an electromagnet and a corresponding armature or an electrifiable coil with a core, which is able to move in an electromagnetic field generated by the electrified coil, a so-called solenoid.

Known armatures are moveable in the electromagnetic field or are fixed relative to a moveable electromagnet and may themselves be a permanent magnet or an electromagnet .

Electromagnetic relays have been, in principle, known since 1926 and comprise a coil and iron core arrangement as electromagnet and a moveable armature, which is spaced apart from the electromagnet by a spring. An electromagnetic attractive force generated by the electromagnet, which is greater than a force generated by the spring -spring force-, moves the armature towards the electromagnet into an active position. A contact arm of the armature comprises a resiliently seated, moveable contact member. When the armature is in the active position, the moveable contact member contacts a corresponding fixed contact member electrically conducting, such that, via both contact members, a first electrical circuit is closed. The resilient seating of the moveable contact member provides an individual contact pressure .

The gap between the electromagnet and the armature causes an electromagnetic field loss, however, if the armature moves towards the electromagnet, the gap between the electromagnet and the armature decreases, such that the field loss is reduced. As a result, an accelerated movement of the armature towards the electromagnet is caused, and, as movement of the armature causes movement of the moveable contact member towards the fixed contact member, undesired bounce of the contact members is caused, depending on the kinetic energy of the moveable contact member.

If an electrical current supplying the electromagnet is switched off, the electromagnetic field begins to collapse, resulting in reduction of the electromagnetic attractive force. As soon as the electromagnetic force falls below the spring force, the armature begins to move towards an inactive position due to the spring force. As a result, the moveable contact member is also moved towards an open position, such that the first electrical circuit opens. However, normally the electromagnetic field is at least partially maintained for a certain span of time following the switch off of the electrical current, so that movement of the contact members into the open position, which results in opening of the first electrical circuit, is undesirably delayed or even impossible .

These relays are generally large, have a high energy consumption and their manufacture is cost intensive. In addition, the electromagnetic relays suffer from an undesired dissipation of heat, and the large dimensions of the electromagnetic actuators can result in undesired electromagnetic interference affecting electrical circuits and/or devices related with the relay.

A reduction of dimensions of the electromagnetic actuating means results in an undesired reduction of performance of the relay, particularly with respect to a current carrying capacity of the first electrical circuit and/or the contacts.

It is therefore desirable to have an alternative switching device which overcomes or at least reduces at least one of the above mentioned disadvantages, which is achieved by the present invention.

In a first aspect of the invention there is provided a switching device comprising at least one first and second contact member. The at least one first contact member is adapted to be moveable relative to the at least one second contact member by at least one electromechanical actuating means, to reversibly electrically contact the at least one second contact member. This advantageously reduces an energy consumption of the switching device and also reduces electromagnetic disturbance of electrical circuits and/or electrical devices related with the switching device. Furthermore, due to the electromechanical actuating means, the switching device has reduced dimensions compared with the electromagnetic relays as known in the art.

It will be appreciated that the term "electrically conducting contact" is to be understood as to relate to a contact having an ability to conduct an electrical current. The first and second contact members contact, e.g. abut, each other in a closed position and enclose a gap if they are in an open position. The first contact member can be a moveable contact member and the second contact member can be a fixed or a moveable contact member. In addition, the term "connected with" is used to describe a direct connection or an indirect connection via at least one intermediate part or element, whereas the terms "connected to" and "engage" are used to describe a direct connection and/or interaction. Furthermore, if hereinbefore or hereinafter the terms "a first (/second) contact member" or "the first (/second) contact member" are used, these terms relate to at least one contact member, e.g. one, two, three or a multiplicity of contact member ( s ) .

An electrical circuit may be establishable or de-establishable, e.g. may be closed or opened, by moving the first and second contact members in the closed or open position, respectively.

In a preferred embodiment, the electromechanical actuating means is controllable, e.g. actuatable, by at least one control circuit. An electrical current in the control circuit is transformed by the electromechanical actuating means into a mechanical force, which is transferred to the first contact member to move the latter, such that the first and second contact members electrically contact each other. Advantageously, the electrical circuit and the control circuit are electrically separated by the electromechanical actuating means, which prevents undesired electrical induction and/or leakage current.

In addition, a signal may be generated in relation to a trigger event, by which the control circuit can directly or indirectly be controlled to control the switching device. Advantageously, the electromechanical actuating means is adapted to disengage the first and second contact members by moving the first contact member into an open position if the control circuit is opened. If the control circuit is closed, e.g. in relation to the signal, the electromechanical actuating means may move the first contact member into the closed position.

Preferably, the electromechanical actuating means is or com- prises at least one motor. The motor may be an AC motor, a DC motor, a universal motor, an induction motor, a stepper motor, a linear motor or the like, or a combination thereof. Utilisation of a motor is an advantageous alternative to the electromagnetic relays known in the art . The electromechanical actuating means can easily be adapted to different applications and requirements . If the motor is a stepper motor, it can be precisely controlled and/or positioned, and if the motor is a linear motor, a high acceleration is advantageously provided. Furthermore, elec- tromagnetic interference resulting from any such electromechanical actuating means can more easily be shielded as opposed to any such provisions for electromagnets of conventional relays .

One electromechanical actuating means may be adapted to move the first electrical contact (s) of more than one switching device, for example a motor can be connected with intermediate parts adapted to transfer the mechanical force to a multitude of first electrical contacts . Two or more switching devices sharing one electromechanical actuating means involves the advantage of reduced electromagnetical interference, particularly if the electromechanical actuating means is mounted apart from the switching device (s) .

Preferably, the first contact member is directly or indirectly connectable with the electromechanical actuating means. For example, the first contact member is permanently or temporarily connected with the electromechanical actuating means by a connecting means, e.g. a transmission means, transmission assembly, intermediate means , lever, resilient means or the like, or a combination thereof. As will be appreciated, indirectly moving the first contact member advantageously provides a more flexible arrangement of components of the switching device and allows adaptation of the switching device, a housing of the latter et cetera, to different requirements regarding size and/or shape.

The electromechanical actuating means is adapted to exert at least one first force to move the first contact member. The first force is applied by the electromechanical actuating means directly or indirectly to the first contact member. In a preferred embodiment, the switching device further comprises at least one resilient means, for example a spring or the like, adapted to apply at least one second force to at least a part of the first contact member in a direction substantially opposite to the direction of the first force. As the second force is a counterforce to the first force, and the first contact member is moveable from the closed into the open position by the second force and from the open into the closed position by the first force, activation of the electromechanical actuating means is not essentially required for moving the first contact member into the open position. As a result, energy consumption and/or heat dissipation by the electromechanical actuation means is ad- vantageously reduced.

Advantageously, the electromechanical actuating means is or comprises at least one stored energy spring actuator, facilitating reduction of energy consumption and heat dissipation, and resulting in further reduced dimensions of the switching device .

In a second aspect of the invention there is provided a method of assembling the switching device, wherein the at least one first contact member and the at least one electromechanical actuating means may be connected with each other. The first contact member and the electromechanical actuating means are reversibly or irreversibly engaged or connected, i.e. connected with each other by at least one intermediate means. The intermediate means may be at least one transmission means, transmission assembly, lever, resilient means (e.g. a spring etc.) or the like, or a combination thereof .

Advantageously, the first contact member and/or the electrical circuit is electrically separated from the at least one electromechanical actuating means and/or control circuit. Thereby, electrical disturbance and detrimental influences between the electrical circuit and the control circuit are prevented or at least reduced.

In a third aspect of the invention there is provided a method of operating a switching device as hereinbefore and hereinafter described, wherein the at least one first contact member may be moved relative to the at least one second contact member by at least one such electromechanical actuating means , to reversibly electrically contact the second contact member. In a further aspect of the invention there is provided an electrical circuit comprising at least one switching device as hereinbefore and hereinafter described. In addition, the electrical circuit may comprise at least one electrical load.

In a still further aspect of the invention there is provided an electrical device comprising at least one switching device as hereinbefore and hereinafter described and/or comprising at least one electrical circuit comprising at least one such switching device.

An embodiment of the present invention will hereinafter be described with reference to the accompanying drawings by way of example only, wherein

FIG 1 shows a schematic representation of an embodiment of a switching device according to the present invention,

FIG 2 shows a schematic view of an electromagnetic relay ac- cording to the state of the art, and

FIG 3 shows a schematic view of a further embodiment of a switching device according to the present invention.

In FIG 1, a schematic representation of an embodiment of a switching device 10 according to the present invention is shown. The switching device 10, which is comprised by an assembly 12, has a first and second contact member 14, 16. The first contact member 14 is moveable relative to the second contact member 16 by an electromechanical actuating means 18. When the first contact member 14, which can reversibly electrically contact the second contact member 16, contacts the second contact member 16, an electrical circuit 20 is closed, and when the first and second contact members 14, 16 are spaced apart, i.e. enclose a gap, such that they are not connected electrically conducting, the electrical circuit 20 is opened.

A control circuit 22 is adapted to control the electromechanical actuating means 18. For example, the control circuit 22 may be controllable by a trigger event, such that the electromechanical actuating means 18 can be activated or deactivated, thereby resulting in subsequent engagement or disengagement of the first and second contact members 14. 16.

FIG 2 shows a schematic longitudinal cut view of the assembly 12 comprising an electromagnetic relay 24 according to the prior art. The relay 24 opens or closes the electrical circuit 20 (shown in FIG 1) , which is connected with the second contact member 16 via a first and second conductor 26, 28 of the assembly 12.

An electromagnetic actuator 29 of the relay 24 has a first part 30 and a corresponding second part 32. The first part 30, which comprises an electromagnet 34 with a coil 36 and a core 38, e.g. an iron core, is affixed to a base member 40 of a housing 42 of the assembly 12. The second part 32 is a moveable armature, which is spaced apart from the first part 30 by a resilient means 44, which is shown as a spring.

The first contact member 14, which is shown here as a contact bridge 46 comprising a first and second moveable contact 48, 50 located on opposing end portions of the contact bridge 46, is connected to a spring 52. The spring 52 is connected to a top portion 54 of a connecting means 56, which is connected with the second part 32. The second contact member 16 is shown here as a first and second fixed contact 58, 60 connected with the first and second conductor 26, 28, and the first fixed contact 58 corresponds with the first moveable contact 48 and a second fixed contact 60 corresponds with the second moveable contact 50. According to the present invention there is provided an electromechanical actuating means 18, which replaces the electromagnetic actuator 29 of the electromagnetic relay 24 as known in the art .

In FIG 3 , a schematic view of a further embodiment of the switching device 10 according to the present invention is shown. The switching device 10 is partially similar to the relay 24 as shown in PIG 2 and comprises first and second contact members 14, 16. The first contact member 14 is connected to a spring 52, which is connected to a top portion 54 of a connecting means 56. The electromechanical actuating means 18, which is shown here as a motor 70 and an intermediate means 72 (e.g. a transmission means or the like) , is adapted to move the first contact member 14 relative to the second contact member 16. The motor 70 is affixed to a base member 40 of a housing 42 of the assembly 10, however, it will be appreciated that it may be permanently or releasably affixed, e.g. glued, snap fixed, screwed, riveted, welded or the like, to any suitable part of the housing 42, switching means 10, assembly 12 or any suitable part related with the assembly 12, et cetera. The motor 52, which may be an AC motor, a DC motor, universal motor, induction motor, stepper motor, linear motor or the like, is connected with the connecting means 56 by the intermediate means 72. It will be appreciated that the motor 70 may be permanently or temporarily connected to the intermediate means, which may be permanently or temporarily connectable with the connecting means 56 or any suitable part of the switching device 10, which is able to facilitate movement of the first contact member 14. In addition, two or more intermediate means may be adapted to transmit a force exerted by the motor 70 directly or indirectly to the first contact member 14 (shown in PIG 1) in order to move the latter. The actuating means 18 is adapted to exert a first force, which can be applied directly or indirectly to the first contact member 14 to move the latter relative to the second contact member 16.

Additionally, the switching device 10 can further comprise at least one resilient means - second resilient means (not shown) similar to the resilient means 44 as shown in FIG 2, adapted to apply a second force directly or indirectly to the first contact member 14 in a direction substantially opposite to the direction of the first force. The second force, by which the first contact member 14 is moveable in a direction substantially opposite to the direction by which it can be moved by the first force, can therefore be regarded as a counterforce to the first force.

In an alternative embodiment the electromechanical actuating means 18 comprises a stored energy spring actuator (not shown) instead of the motor 70.

Operation of the electromechanical actuating means 18 is now briefly described with reference to FIG 1.

The actuating means 18 may be activated by, e.g. , a trigger event. In relation with the trigger event, an activation signal is generated, by which the control circuit 22 is directly or indirectly closed, such that the actuating means 18 is activated. By the activated actuating means 18, the first contact member 14 is moved from an open position, in which the electrical circuit 20 is open, towards a closed position, in which the first and second contact members 14, 16 contact each other electrically conducting, such that the electrical circuit 20 is closed. The conducting contact of the first and second contact members 14, 16 can be maintained by substantially permanent activation of the electromechanical actuating means 18. Alternatively, the electromechanical actuating means 18 can be "switched off" if the first and second contact members 14, 16 are brought into conducting contact, i.e. the control circuit 22 can be opened, and the first and second contact members 14, 16 are retained in conducting contact for a preset or variable amount of time. If the first and second contact members 14, 16 are in conducting contact, the contact can be opened by the actuating means 18, which moves the first contact member 14 from the closed towards the open position. Alternatively, a further element, e.g. a resilient means, can apply a second force to the first contact member 14 or to any suitable part, which is related with the movement of the first contact member 14 towards the open position, such that the electrical circuit 20 is opened. Under exertion of the second force, the actuating means 18 is reset, e.g. brought into a starting position, in which the actuating means 18 does not exert the first force.

It will be appreciated that various modifications may be made to the invention as hereinbefore and hereinafter described without departing from the scope thereof.

In essence, the present invention relates to switching device 10 comprising at least one first contact member 14 being moveable relative to at least one second contact member 16 to reversibly electrically contact the at least one second contact member 16, wherein the at least one first contact member 14 is moveable by at least one electromechanical actuating means 18 , to a method of assembling such a switching device 10, wherein the at least one first contact member 14 and the at least one electromechanical actuating means 18 are connected, to a method of operating such a switching device 10, wherein the at least one first contact member 14 is moved relative to at least one second contact member 16 by at least one electromechanical actuating means 18 to reversibly electrically contact the second contact member 16, to an electrical circuit comprising at least one such switching device 10 and to an electrical device comprising at least one such switching device 10 and/or at least one such electrical circuit. Reference signs

10 switching device

12 assembly 14 first contact member

16 second contact member

18 actuating means

20 electrical circuit

22 control circuit 24 electromagnetic relay

26 first conductor

28 second conductor

29 electromagnetic actuator

30 first part 32 second part

34 electromagnet

36 coil

38 core

40 base member 42 housing

44 resilient means

46 contact bridge

48 first moveable contact

50 second moveable contact 52 spring

54 top portion

56 connecting means

58 first fixed contact

60 second fixed contact 70 motor

72 intermediate means

Claims

1. A switching device (10) comprising at least one first contact member (14) being moveable relative to at least one second contact member (16) to reversibly electrically contact said at least one second contact member (16) , characterised in that the at least one first contact member (14) is moveable by at least one electromechanical actuating means (18) .

2. The switching device as claimed in Claim 1, wherein said electromechanical actuating means (18) is controllable by at least one control circuit (22) .

3. The switching device as claimed in Claim 1 or 2 , wherein said electromechanical actuating means (18) comprises at least one motor (70) .

4. The switching device as claimed in Claim 3 , wherein said motor (70) is at least one stepper motor.

5. The switching device as claimed in Claim 3, wherein said motor (70) is at least one linear motor.

6. The switching device as claimed in any one of Claims 3 to 5, wherein said first contact member (14) is connectable with said motor (70) .

7. The switching device as claimed in any one of Claims 1 to 6, wherein said electromechanical actuating means (18) is adapted to apply at least one first force to move the first contact member (14) , and wherein said switching device (10) further comprises at least one resilient means (44) adapted to apply at least one second force to the first contact member (14) in a direction substantially opposite to the first force.

8. The switching device as claimed in any one of Claims 1 to 7 , wherein said actuating means (18) comprises at least one stored energy spring actuator.

9. A method of assembling a switching device (10) as claimed in any one of Claims 1 to 8 wherein the at least one first contact member (14) and said at least one electromechanical actuating means (18) are connected.

10. A method of operating a switching device (10) as claimed in any one of Claims 1 to 8 , wherein the at least one first contact member (14) is moved relative to at least one second contact member (16) by at least one electromechanical actuating means (18) to reversibly electrically contact the second contact member (16) .

11. An electrical circuit comprising at least one switching device (10) as claimed in any one of Claims 1 to 8.

12. An electrical device comprising at least one switching device (10) as claimed in any one of Claims 1 to 8 and/or comprising an electrical circuit as claimed in Claim 11.