AU633425B2

AU633425B2 - Switch mechanism for low-voltage switching devices

Info

Publication number: AU633425B2
Application number: AU76112/91A
Authority: AU
Inventors: Johannes Becker
Original assignee: Felten and Guilleaume Energietechnik AG
Current assignee: Felten and Guilleaume AG
Priority date: 1990-04-30
Filing date: 1991-04-29
Publication date: 1993-01-28
Anticipated expiration: 2011-04-29
Also published as: EP0454963B1; AU7611291A; DE4013840A1; EP0454963A1; ATE106159T1; DE59101700D1; JPH04230926A; CN1020521C; DE9004883U1; CN1056183A; ES2053222T3

Abstract

The aim exists to reduce the size of low-tension switchgears, but on the other hand it is intended to improve the switching power. New requirements now demand that the contacts of the low-tension switchgears close more quickly in order to achieve a small amount of contact erosion and hence a longer life of the low-tension switchgears. The invention indicates a means by which a switching mechanism is produced with only a few individual parts, a bell crank system 2, 3, 4 drives a contact shaft 6 via a switching lever 1, a locking device 9, 10, 11 initially locks the contacts 7, 8 shortly before touching, and, in the case of further operation of the switching lever 1, switches on suddenly, and a trip device 14, 16, 18 opens the contacts 7, 8 in the case of a fault current. Such a switching mechanism can be used in low-tension switchgears, preferably in fault-current protection switches. <IMAGE>

Description

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SPECIFICATION

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Form 633425 FOR OFFICE USE i I 4~ Short Title: Int Cl: Application Number; Lodged: Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Related Art: TO BE COMPLETED BY APPLICANT TO BE COMPLETED BY APPLICANT je Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: FELTEN GUILLEAUME ENERGIETECHNIK

AKTIENGESELLSCIAFT

Schanzenstrasse 24-30, D-5000 KOLN

GERMANY

Johannes Becker GRIFFITH HACK CO 71 YORK STREET SYDNEY NSW 2000 Complete Specification for the invention entitled: SWITCH MECHANISM FOR LOW-VOLTAGE SWITCHING DEVICES The following statement is a full description of this invention, including the best method of rforming it known to us:- GH&CO REP: 21507-B:CLC:RK *0 5337A:rk a JLIL, I 2 Description: Switch mechanism for low-voltage switching devices.

The invention concerns a switch mechanism for lowvoltage switching devices in accordance with the preamble of Claim i.

Such a switch mechanism for actuating the electrical contacts of a switching device is known (DEP 35 08 110). This known switch mechanism is described as 9 having a blocking element which serves as a means of temporarily holding back the switch contacts just tII. before they make contact with ono another. This pretensioned blocking element holds a switching pivot which transmits the retaining force to the switch contacts by way of a disc until such time as the preselectable force required to turn the switch knob to the making position is reached. As the force at the switch knob increases, energy is stored through elastic deformation of the switching elements between the switch knob and the switching pivot. Once the force at the switch knob is overcome, the pretensioned blocking element deflects and the disc of the switching pivot rolls out of its retaining position along the circular contour of the blocking element. Upon deflection of the pretensioned blocking element and its release of the disc, the switching pivot snaps into the making position, effecting an instantaneous contact between the switching contacts S. of the switching device. This type of switch mechanism is intended for use with conventional earth leakage circuit breakers. Developments in this field are such, however, that earth leakage circuit breakers are becoming smaller, which in turn means that less space is available for the switch mechanism.

3 The invention is based on the technical problem of developing, for an earth leakage circuit breaker, a switch mechanism which can be installed in a small given space and is nonetheless able to meet all requirements in respect of switching capacity, service life and suitability for use in any climate.

According to the present invention there is provided a switch mechanism for low-voltage switching devices comprising, a switch lever having a projection member, a spring element having a spring which is compressible and is connected at one end with the switch lever, a set of contacts comprising a stationary contact and a movable contact, a blocking device comprising a first lever having an abutment, and at one end pivotally connected with the switch lever through a first pivot pin, and a second lever pivotally connected at one end to the other end of the first lever through a second pivot pin and at the other end to a movable pivot which is located and is movable within a slot of the second lever, a toggle mechanism comprising the spring element and connected with the second lever through the movable pivot and a contact shaft interconnecting the toggle mechanism and set ,f contacts, wherein, in its uppermost position the second pivot pin defines a dead centre position, when the switch lever is in an OFF position, upon actuation of the switch lever, the spring element displaces the movable pivot from its position at the top of the slot to a position at the bottom of the slot, which causes the toggle mechanism to be activated to cause the contact shaft to move the movable contact towards the stationary .contact, upon further actuation of the switch lever, the spring is compressed until the projection member contacts III: the abutment and further actuation of the switch lever causes the second pivot pin to move from the dead centre position, resulting in the first and second levers snapping into an extended position, thereby unblocking the toggle mechanism and allowing the set of contacts to close instantaneously.

S:21507B/438/10.11.92 -4 The advantages achieved with the preferred embodiment of the invention consist in the fact that an extremely space-saving switch mechanism has been developed for use in various types of switches, and especially in earth leakage circuit breakers. Besides its reliability, special mention should also be made of its low-cost of manufacture.

For example, it is advantageous that, in the case of this switch mechanism, the force transmitted from the contacts to the tripping lever by way of the connecting plate, the link and the toggle is partially compensated by a corresponding, counteracting torque which is applied to the tripping lever by the torsion spring. The amount of force compensation can be rated in such a way that the residual, uncompensated force can serve to overcome the frictional forces of the individual component parts, ensuring a reliable tripping action. Thus it is possible to reduce the deflecting force acting on a pivoted resetting plate to a minimum, and a tripping relay with a relatively weak actuating force can bE! used.

After a circuit breaking operation has been performed by the tripping relay, the latter must be reset to its initial position. This resetting operation is performed with advantageous effect by a resetting plate which is pivot-mounted and, when the switch mechanism is in the off poDsition, is turned by the end of the connecting plate in a clockwise direction, whereby a lever belonging to the resetting plate presses against the pin of the tripping relay and resets it. The resetting plate is fabricated from resilient metal with :the effect that its levers function as leaf springs.

These leaf springs are so rated that they will deform plastically when subjected to a force which is greater othan, the required resetting force. To compensate any manufacturing tolerances, this resetting plate can be manufactured with a certain oversize; initial actuation and the resultant plastic deformation will adapt the resetting plate to the actual installation conditions.

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irmm. r~-aYca~fs~ -4A- This resetting plate serves to ensure that the tripping relay can be completely reset without subjecting it to excessive force.

A preferred embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings as follows: Fig. 1 A switch mechanism for an earth leakage circuit breaker in the OFF position, shown in side elevation Fig. 2 This same switch mechanism in the blocked position, shown in side elevation Fig. 3 This same switch mechanism in the ON position, shown in side elevation Fig. 4 This same switch mechanism in the OFF position, after being tripped by a leakage current, shown in side elevation.

According to Figs. 1 to 4, the earth leakage circuit breaker can be switched on and off manually by means of a switch lever 1. To this end the switch lever 1 is 20 connected to a toggle mechanism consisting 0 0 a 4 I o a~r 064t S:21507B/438/10.11.92 P- I~~Fllli of a spring element 2, a link 3 and a connecting plate 4. The toggle mechanism has a common pivot which is movable. The connecting plate 4 is connected to a contact shaft 6 on which is mounted a moving contact 7 which mates with a stationary contact 8.

Also connected to the switch lever 1 is a blocking device comprising a short lever 9 and a long lever Both levers have a common pivot 11. The short lever 9 is connected directly with the centre pivot of the switch lever i, whilst the free end of the long lever 10 corresponds with the common pivot 5 of the toggle mechanism and is provided at this point with a slot Provided for the circuit breaking operation are a tripping lever 16, a resetting plate 18 and a detent 22. As soon as the tripping relay 20 responds, the resetting plate 18 and the detent 22 rotate in a counterclockwise direction, whereby the tripping lever 16 is released and rotates likewise in a counterclockwise direction. The resetting plate 18 and the detent 22 rotate on a common pivot 19. The rotation of the tripping lever 16 also permits rotation of a toggle 14 which in turn causes the toggle mechanism to open the contacts 7 and 8. The tripping lever is provided with a torsion spring 17.

All components, including the tripping relay, but excluding the contact shaft 6 and the contacts 7 and 8, are housed in a switch lock mechanism 21.

The moce of operation of the switch mechanism is as S: follows: The switch lock mechanism 21 is provided with a quick circuit-making function and a displacement-dependent blocking device. In the OFF position shown in Fig.l, the levers 9 and 10 form, together with the pivot 11, a toggle mechanism positioned beyond dead-centre. In the blocking position shown in Fig.2, the toggle mechanism comprising the spring element 2, the link 3 and the connecting plate 4 is locked in a position in which contact has 4r still not been made. Furthey actuation of the switch lever 1 causes a compression spring in the telescopic spring element 2 to be compressed until the projection 12 of the switch lever 1 touches the projection 13 of the short lever and the lever system comprising levers 9 and continues to move until it reaches beyond the deadcentre position and snaps into its extended position and instantaneously unlocks the toggle mechanism 2, 3 and 4, whereby the contacts 7 and 8 likewise close instantaneously.

The circuit-breaking operation is performed by the tripping lever 16, the resetting plate 18 and the detent 22. When the tripping relay 20 responds, the resetting plate 18 and the detent 22 rotate in a counterclockwise direction, whereby the projection 23 of the detent 22 releases the tripping lever 16 which can now rotate in a counterclockwise direction and the toggle mechanism 2, 3 and 4 can, through clockwise rotation of the toggle 14, move to the left and the contact shaft 6 can move into the OFF position, as shown in Fig.4.

t4 6

Claims

1. A switch mechanism for low-voltage switching devices comprising, a switch lever having a projection member, a spring element having a spring which is compressible and is connected at one end with the switch lever, a set of contacts comprising a stationary contact and a movable contact, a blocking device comprising a first lever having an abutment, and at one end pivotally connected with the switch lever through a first pivot pin, and a second lever pivotally connected at one end to the other end of the first lever through a second pivot pin and at the other end to a movable pivot which is located and is movable within a slot of the second lever, a toggle mechanism comprising the spring element and connected with the second lever through the movable pivot and a contact shaft interconnecting the toggle mechanism and set of contacts, wherein, in its uppermost position the second pivot pin defines a dead centre position, when the switch lever is in an OFF position, upon actuation of the switch lever, the spring element displaces the movable pivot from its position at the top of tne slot to a position at the bottom of the slot, which causes the toggle mechanism to be activated to cause the contact shaft to move the movable contact towards the stationary 25 contact, upon further actuation of the switch lever, the spring is compressed until the projection member contacts the abutment and further actuation of the switch lever causes the second pivot pin to move from the dead centre position, resulting in the first and second levers snapping into an extended position, thereby unblocking the toggle mechanism and allowing the set of contacts to close instantaneously.

2. A switch mechanism as claimed in claim 1, wherein the slot extends along a central axis of the 35 second lever.

3. A switch mechanism as claimed in claim 1 or claim 2, wherein the spring is connected with the switch lever at one end and with the movable pivot at its other p: cc 5 cc cc to ar col co: 15 le- wh prc mer of res unl occ 25 whe mat whe: con 30 loc 0 o I *0 0 0 4 O I 0 O o a or-~ 0 Ot(*y 0 0 d ft 0 i S' 00 0( *400L O 0 O IOU., 0 0, tO '0 0 .14i *t40 whe2 trir 35 wher the wher S;21507B/10.11.! S:21507B/10.11.92 8 end.

4. A switch mechanism as claimed in any one of the preceding claims, wherein the toggle mechanism further comprises a connecting lever pivotally connected to the contact shaft, and a link connected with a toggle component.

A switch mechanism as claimed in claim 2, wherein the spring element comprises a spring link interconnecting the spring and switch lever.

6. A switch mechanism as claimed in claim 4, the toggle mechanism having a torsion spring which is arranged to apply a counteracting force to partially compensate for the force transmitted from the set of contacts to the tripping lever through the connecting lever, link and toggle component.

7. A switch mechanism as claimed in claim 6 or 4, wherein in the OFF position, a resetting plate which is provided with two lever arms can be turned on a pivot member by one end of the connecting lever, such that one of the lever arms depresses a pin of a tripping relay to reset the tripping relay, the tripping relay being for unlocking the toggle mechanism if a fault condition occurs.

8. A switch mechanism as claimed in claim 7, wherein the resetting plate is fabricated from resilient material.

9. A switch mechanism as claimed in claim 8, wherein the switch mechanism excluding the set of contacts and contact shaft are housed within a switch 30 lock mechanism.

A switch mechanism as claimed in claim 9, wherein the lock mechanism includes space for the tripping relay.

11. A switch mechanism as claimed in claim 4, wherein one end of the connecting lever, and one end of the link is connected with the movable pivot.

12. A switch mechanism as claimed in claim 11, wherein in the OFF position the second lever is 4 44 SI,r '4 4 4 S:21507B/10.1 1.92 r' i I:j 9 substantially vertically oriented with respect to the link and connecting lever, which are respectively arranged on opposite sides of the second lever.

13. A switch mechanism substantially as hereinbefore described with reference to the accompanying drawings. DATED this 10th day of November 1992 FELTEN GUILLEAUME ENERGIETECHNK AKTIENGESELLSCHAFT By their Patent Attorneys GRIFFITH AACK CO. I.

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