GB2371409A

GB2371409A - Rotary switch

Info

Publication number: GB2371409A
Application number: GB0129393A
Authority: GB
Inventors: Bogdan Zabrocki
Original assignee: Moeller GmbH
Current assignee: Eaton Industries GmbH
Priority date: 2000-12-09
Filing date: 2001-12-07
Publication date: 2002-07-24
Anticipated expiration: 2021-12-07
Also published as: DE10061394A1; FR2818003B1; GB2371409B; DE10061394B4; ITMI20012520A1; GB0129393D0; FR2818003A1

Abstract

A switch device for a low-voltage power switch comprises a pair of fixed contacts 26, 28 on current bars 30, 32 , and a floatingly mounted, double-break rotary contact 14 . Two contact pressure springs 42, 44 provide for symmetrical loading of the rotary contact 14 and the contact elements.

Description

IMPROVEMENTS IN AND RELATING TO SWITCHES

The invention relates to a switch device with floutingly mounted, doublebreak rotary contact, in particular for a multi-pole power switch, as set forth in the 5 classifying portion of the main claim.

A double-break switch device without the movable contact portion bemg mounted fixedly in relation to space, for example as disclosed in EP 314 540 B1, involves the problem of uniform distribution of the contact pressure to the two fixedly installed contacts. The position of the movable contact with respect to the fixedly 10 installed contacts can vary during the service life of the switch. The distribution of force and position of the co-operating switch elements must still be present after a large number of switching operations when the switch elements have suffered from wear. In the above-indicated switch device a respective contact pressure spring is arranged on a side of the movable contact portion and is intended to cause a self 15 centering action. However the torques of the contact pressure springs produce a laterally deflecting force on the contact portion. The lateral deflection is limited by the movable contact portion being guided in slots in partitioning walls which divide the housing into separate chambers for the arc extinguishing plates. The structure of the housing is made more complicated by virtue of the partitioning walls. With increasing 20 wear and accompanying tilting of the movable contact portion when switching movements are performed, contact can occur in the slots and therefore frictional losses can be produced in the slots.

An object of a preferred embodiment of the invention is to provide an improved double break rotary contact without mounting fixedly in relation to space for 25 the movable rotary contact portion so that asymmetrical tilting moments on the movable rotary contact portion do not occur.

According to the invention there is provided a switch device with floutingly mounted, double-break rotary contact, in particular for a multi-pole low-voltage power switch comprising an insulating housing, a switch drive which is associated with each 30 pole and which is mounted rotatably in mountings in the insulating housing about an axis perpendicularly to the longitudinal extent of the rotary contact, including: two stationary contact portions, a rotary contact in the form of a floutingly mounted, double-arm contact portion with end contacts which co-operate with the stationary

contact portions, two contact pressure springs which are supported on the contact portion and which respectively apply to the contact portion a torque directed in the closing direction of movement, wherein provided on each contact pressure spring on the one hand is an entrainment element cooperating with the switch drive and on the 5 other hand a support element acting on the contact portion, both contact pressure springs being arranged on a mounting pin on the contact portion and being such that they exert on each side of the contact portion a torque which symmetrically loads the stationary contact portions and the end contacts.

Advantageously a switch device according to the invention provides that both 10 contact pressure springs exert on each side of the rotary contact portion a torque which is as equal as possible for symmetrically loading the fixed contact portions and the end contacts. In that way it is possible to eliminate guide slots for the rotary contact portion and it is possible to omit partitioning walls in which the guide slots have to be 1 5 provided.

An excellent self-centering action for the rotary contact portion is preferably achieved by the particular configuration of the contact pressure springs, preferably in the form of torsion springs.

Assembly of the rotary contact can be simplified as the housing can be of a 20 simpler design configuration.

A switch device according to the present invention - without limiting the claimed subject-matter thereto - may comprise the following: the switch device is provided in particular for a multi-pole low-voltage power switch with an insulating housing, and includes a double-break rotary contact with a switch drive associated 25 with each pole, which is mounted rotatably in mountings in the insulating housing about an axis perpendicular to the longitudinal extent of the rotary contact. The actual switch comprises two stationary contact portions which are connected to current bars, a floutingly mounting rotatable contact portion which is of a double-arm configuration and which carries end contacts co-operating with the stationary contact portions. Two 30 contact pressure springs preferably in the form of torsion springs - are supported on a mounting pin against the rotary contact portion and respectively apply to the rotary contact portion a torque which is directed in the closing direction of movement. The contact pressure springs otherwise do not have any further support on or in the switch

f housing. Preferably the contact pressure springs on both sides of the rotary contact portion are of a symmetrical configuration in respect of shape and application of force, wherein one end of each contact pressure spring is in the form of an entrainment element co-operating with the switch drive and the other end of each contact pressure 5 spring is in the form of a support element acting on the rotary contact portion.

A further embodiment of the invention may have the following configuration.

The support element of each contact pressure spring is in the form of a leg which is disposed in parallel relationship with the axis of the torsion spring, and otherwise the contact pressure springs are of paired symmetrical relationship on both sides of the leg.

10 The leg may be disposed parallel to the axis of rotation and transversely with respect to the longitudinal direction of the switch portion.

The length of the leg of one of the contact pressure springs may be greater than the total length of the other contact pressure spring so that the other contact pressure spring can be inserted into the space spanned by the leg of the first contact pressure 15 spring.

The contact pressure springs may be in the form of torsion springs, on both sides of their legs. The partial springs suitably have mutually opposite winding directions. The mounting pin is preferably of a cylindrical round configuration and is 20 arranged perpendicularly to the longitudinal direction of the switch portion.

The present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an exploded view of a switch device according to an embodiment of the invention, 25 Figure 2 is a perspective view of a housing half with inserted components, Figure 3 shows the details comprising current bars, rotary contact portion, torsion springs and entrainment means, Figure 4 is a side view on to the opened housing (as shown in Figure 2), Figure 5 is a plan view on to the assembly with partially sectioned housing, and 30 Figure 6 shows both torsion springs.

Figure 1 is an exploded view of a low-voltage power switch 10. The current path of the contact passes through the housing 12 of injection- moulded insulated material. The current path is opened and closed by a double-break switch portion (in

the form of a rotary contact) 14. The switch portion 14 is movable about the axis of rotation 16 between a closed and an open position. The switch portion 14 is in the form of a double-arm lever with the lever arms 18, 20, whose ends (end contacts 22, 24) are coated with contact coatings of contact material. The end contacts 22, 24 respectively 5 co-operate with the two oppositely disposed contact coatings 26, 28 (fixed contacts) and form contact pairs. In Figure 1 the end contacts 22, 24 and the contact coatings 26, 28 are shown as still separate from the lever arms 18, 20 and the current bars 30, 32. In manufacture they are respectively soldered on to the corresponding supports.

The electrical connection of the current path is made at the current bars 30, 32 10 (in a manner not shown in the drawing) which issue at two opposite sides of the housing 12. The housing is made up of two halves and is preferably of mirror-image symmetrical configuration so that it can be assembled from two identical housing halves 12a, 12b.

Associated with each of the contact pairs 22, 28 and 24, 26 respectively is an 15 arc extinction chamber 36 and 38 respectively with a pack of extinction plates which are disposed on respective opposite sides in the housing 12.

In the switched-on position of the switch the rated current flows through the current path, in which respect it enters through one of the current bars, flows through the fixed contact 26, the switch portion 14 and the fixed contact 28, and leaves the 20 housing by way of the other current bar with connecting lug. By rotation of the movable switch portion 14 in the clockwise direction the two contact pairs 22, 28 and 24, 26 are separated and at the same time two arcs which are in series are formed. The current bars 30, 32 are preferably in the form of a current loop in order to utilise the electrodynamic effect for rapid switch opening.

25 The switch drive actuates the switch portion 14 by means of entrainment members 40a and 40b which are provided in coaxial relationship with the axis of rotation 16. The entrainment members are in the form of half-shell portions which are mounted rotatably in the bores 39 of the housing halves 12a, 12b. The bores 39 form for the switch drive a fixed axis transversely with respect to the longitudinal direction 30 of the switch portion. The two half-shell portions 40a, 40b extend around the rotary contact portion with the exception of recesses 50, 50' which are present at the inner edge and through which the lever arms 18, 20 project. The entrainment action on the

lever arms 18, 20 is achieved by abutments 48, 48', 49, 49' at the housing edge of the entrainment half-shell portions 40a, 40b.

The actuating mechanism by way of the switch cam is mechanically coupled to the entrainment members 40a, 40b in order to transmit the opening and closing S movements to the various current paths of the switch. The details of the actuating mechanism are not illustrated.

The rotatable switch portion 14 is held and guided by the torsion springs 42, M (see also Figure 6). The torsion springs are mounted on a mounting pin 21, which extends on both sides of the rotary contact portion 14 coaxially along the axis of 10 rotation 16. The mounting pin 21 can be pressed into a central bore in the double-arm rotary contact portion 14, during the assembly procedure. The mounting pin 21 does not have any mounting in the entrainment members 40a, 40b. Mounting of the switch portion 14 is effected floutingly in coaxial relationship with the axis of rotation 16. By virtue of the floating mounting of the switch portion and by virtue of the symmetrical IS loading of the two torsion springs 42, 44, the double-break rotary contact 14 is mounted in such a way as to ensure uniform distribution of the contact pressure of the end contacts 22, 24 to the corresponding fixed contacts 26, 28. In that way the movable switch portion 14 is elastically mounted and can compensate for manufacturing tolerances in the individual parts and the housing and contact wear 20 phenomena caused by switching operations. The axis of rotation 16 of the rotary contact portion 14 is a floating axis as it does not involve direct physical mounting.

Figure 2 shows assembly of the parts, corresponding to their position in Figure 1. Figure 3 shows the assembly of the individual parts consisting of current bars 25 30 and 32, rotary contact portion 14, torsion springs 42, 44 and entrainment members 40a, 40b in the two housing halves 12a, 12b.

A side view of the housing half 12a is shown in Figure 4. In particular the positions of the torsion springs 42, 44 are to be emphasised. The torsion springs are carried loosely on the mounting pin 21 so that the torsion springs 42, 44 do not clamp 30 the mounting pin, even in a condition of full tension, and in this respect there is no entrainment action between the mounting pin and the torsion springs.

Figure 5 is a plan view (perpendicular to the view of Figure 4) on to the assembly with partly sectioned housing and partly sectioned entrainment members

40a, 40b. The other parts can be identified in accordance with their references from Figure 1.

Figure 6 shows the contact pressure springs individually and in their position relative to each other and relative to the rotary contact portion. The torsion springs 42 5 and 44 hold and guide the rotary contact portion 14 within the entrainment members 40a, 40b. The contact pressure springs are in pairs on both sides of the rotary contact portion 14 and are symmetrically coaxial along the axis of rotation 16 and are arranged loosely on the mounting 21 (Figure 1). Both torsion springs 42, 44 are wound on both sides of the rotary contact portion 14 with four turns and are supported on the rotary 10 contact portion 14. As both torsion springs act on the rotary contact portion in the closing direction, the one torsion spring 42 engages the top side of the rotary contact portion 14 and the other torsion spring 44 engages the underside thereof.

The support element of each torsion spring relative to the rotary contact portion is in the form of a leg 43, 45. The legs are parallel to the axis of rotation 16 and 1 S transverse with respect to the longitudinal direction of the rotary contact portion.

The length L1' of the leg 43 of one of the contact pressure springs (first torsion spring 42), with the same diameter of the spring turns, is greater than the total length L1 of the other contact pressure spring 44 so that the other contact pressure spring can occupy the space spanned by the leg of the first contact pressure spring. The position 20 of the two torsion springs relative to each other can be clearly seen from Figure 5.

The ends of the torsion springs project beyond the diameter of the spring turn and are each bent over to form a respective entrainment hook 46, 47. The laterally projecting entrainment hooks respectively engage support portions 52, 52' on or in the entrainment half-shell portions, in which respect the support portion 52 (see Figure 1) 25 of the one torsion spring is present in the interior and the support portion 52' of the other torsion spring is present on the surface of the entrainment half- shell portions 40a, 40b. The entrainment hooks are disposed in opposite relationship axially with respect to the axis of rotation 16 of the switch drive.

Claims

l CLAIMS

1. A switch device with floutingly mounted, double-break rotary contact, in 5 particular for a multi-pole low-voltage power switch comprising an insulating housing, a switch drive which is associated with each pole and which is mounted rotatably in mountings in the insulating housing about an axis perpendicularly to the longitudinal extent of the rotary contact, including: - two stationary contact portions, 10 - a rotary contact in the Loran of a floutingly mounted, double-arm contact portion with end contacts which co-operate with the stationary contact portions, - two contact pressure springs which are supported on the contact portion and which respectively apply to the contact portion a torque directed in the closing direction of movement, 15 - wherein provided on each contact pressure spring on the one hand is an entrainment element co-operating with the switch drive and on the other hand a support element acting on the contact portion, both contact pressure springs being arranged on a mounting pin on the contact portion and being such that they exert on each side of the contact portion a torque 20 which symmetrically loads the stationary contact portions and the end contacts.

2. A switch device according to claim 1, wherein the contact pressure springs are in the form of torsion springs.

25

3. A switch device according to claim 2, wherein the torsion springs are provided in paired symmetrical relationship at both sides of the rotary contact portion.

4. A switch device according to claim 2 or claim 3, wherein the support element of each torsion spring is in the form of a leg disposed in parallel relationship 30 with the axis of the torsion spring.

5. A switch device according to claim 4, wherein the length of the leg of one of the torsion springs is greater than the total length of the other torsion spring so that the other torsion spring can fit into the space spanned by the leg of the first torsion spring.

5

6. A switch device according to one of the preceding claims, wherein the mounting pin is arranged perpendicularly to the longitudinal direction of the switch portion.

7. A switch device according to one of the preceding claims, wherein the 10 switch drive is in the form of two entrainment half-shell portions (40.1, 40.2) which extend around the rotary contact portion (14).

8. A switch substantially as described herein, with reference to the drawings hereof