GB2080035A

GB2080035A - Vacuum Switch

Info

Publication number: GB2080035A
Application number: GB8121110A
Authority: GB
Original assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Switzerland; BBC Brown Boveri France SA
Priority date: 1980-07-10
Filing date: 1981-07-08
Publication date: 1982-01-27
Also published as: DE3026197A1

Abstract

The contacts 18, 20 of a vacuum switch are mounted within a chamber 16 and connected to a supply line 10 and a return line 12 respectively and are bridgable by a contact bridge 22 movable by an actuating rod 52. The supply line 10 and return line 12 are surrounded by respectively insulating tubes 28, 30 and the contact bridge 22 is supported on a bellows 48 which surrounds the actuating rod 52. <IMAGE>

Description

SPECIFICATION Vaccum Switch The invention relates to a vaccum switch comprising two fixed contacts lying within a vaccum chamber and connected to a supply line and a return line respectively, said contacts being bridgeable by means of a contact bridge.

A vaccum switch is known comprising two contact points which can be connected by means of a contact bridge operable from the outside by an electromagnetic system. This arrangement presents problems in that the transmission of the magnetic force of the electromagnetic actuating system into the interior of the vaccum container is difficult on account of the insulating wall lying therebetween. Moreover, the arrangement is relatively large.

The invention seeks to provide a vaccum switch which is of more simple construction and can thus be manufactured more economically.

According to the present invention, the supply line and the return line are each surrounded by an insulating tube, and the contact bridge is supported on a bellows which surrounds the actuating rod.

By means of the arrangement according to the invention, all flexible current supply leads are dispensed with. The necessary contact force can be produced by correspondingly choosing the bellows diameter, so that counter springs for reducing the contact force can also be dispensed with. Because of the relatively small mobile contact bridge which is possible thereby, the mobile mass of the contact bridge is reduced, so that contact chatter on switching on can be distinctly reduced.

Preferred features of the invention are set out in the dependent claims.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which; Figure 1 is a diagrammatic illustration of a first embodiment of the invention, Figure 2 is a further embodiment of the invention, Figure 3 is a third embodiment of the invention.

Reference is made to Figure 1. Figure 1 shows a vaccum switch with a supply line 10 and return line 12, with respective fixed contacts 1 8 and 20 fixed to their ends which lie inside the vaccum chamber 14 which is under vaccum and is bounded by a container 1 6. A contact bridge 22 cooperates with the two fixed contacts 1 8 and 20, carries the mobile contacts 24 and 26 respectively.

The feed line and the return line are parallel to each other. Both the supply line and the return line are surrounded by insulating tubes 28 and 30 respectively, which, at that end facing away from the point of contact, are connected in a vaccumtight manner to the supply line 10 and return line 1 2 respectively, by means of fixing elements 32 and 34 respectively. To the ends of the insulating tubes 28 and 30 which face the contact point there are connected support tubes 36 and 38 respectively, which by means of further fixing elements 40 and rigidly connected to the front edge 42 of the container 1 6 which faces up in the drawing. The fixing element 40 can thus be considered as a cover provided with two openings in which the two support tubes 36 and 38 engage, and to which the two said support tubes 36 and 38 are connected (the openings have no reference numerals).Such an arrangement is known, and need therefore be described no further. The container 16 is in the form of two sections, a first section 44 with a larger diameter, in the region of which the two contact points lie, and a second section 46 of smaller diameter, the connection region being frusto conical. The second section 46, with the smaller diameter, encloses a bellows 48, and is firmly connected in a vaccum-tight manner thereto at its end which faces away from the contact points by means of a third fixing element 50.The end of the bellows neighbouring the contact points is firmly connected to the contact bridge, said contact bridge in this case consisting of two parts, namely an inner part 23 carrying the contacts 24 and 26, and an outer part 25 connected in a vaccum-tight manner to the bellows, The connection is made at a separation line 29 by means of a welding or soldering method or, in the present embodiment, by a screw connection 31.

The region of the outer part 25 which lies outside the vaccum is connected to an actuating rod 52, which is operated by means of an actuator, and transmits the actuation force by way of a pin 54 to the outer part 25 (such an arrangement is known). In the interior of the bellows there is also a spiral spring 53 which is guided by a guide 56, and acts against the base 55 of a cup-shaped holder 58, which is connected by means of screw-nut connections 60 to the region 36, or is fixed thereto. The force necessary for the contact pressure is then substantially applied by means of the air pressure plus the compression spring 53.

Screening plates, not shown, are provided in the arrangement of Figure 1 for better action on the metal ions which arise during switch manipulation.

This vaccum switch embodiment is relatively compact constructionally, and can be used in particular as a low voltage switching device.

The switch of Figure 2 has a different arrangement of the supply line 10 and return line 1 2. These lie exactly opposite each other, and their axes are aligned. The two opposing ends in the interior of the arcing chamber 14 carry the fixed contacts 1 8 and 20, which are bridged by means of the contact bridge 22. The supply line 10 and return line 12 are surrounded by insulating tubes 60, 62 respectively, those ends of the two insulating tubes 60 and 62 which face the contact points being firmly connected to the supply line and return line by fixing means 64, 66 respectively.The ends of the insulating tubes 60 and 62 which face away from the contact points have cylindrical extensions 68 and 70, the free ends of which are connected in a vaccum-tight manner by radial intermediate rings to an approximately cylindrical first part and a likewise approximately cylindrical second part respectively of the container 80 which forms the arcing chamber. The first and second parts 76 and 78 surround the insulating tubes 60, 62 respectively, and are aligned with each other and lie concentric to the axes of the supply line 1 0 and return line 12 respectively. The container 8 which completely bounds the arcing chamber has a third part 82 the three parts together forming a T and the part 82 being a cylindrical vessel with diametrically opposing openings in which the parts 76 and 78 are inserted in a vaccum-tight manner.The upper end of the container 80 is firmly connected to a cover 84, while there is fixed to the lower end of the container 80 a second cover 86 with a cylindrical rim 88 which externally surrounds the container 82.

One end of the bellows 48 is fixed to the inside of the part 82 by means 90 with an approximately L or Z-shaped cross section, whereas the other end of the bellows is fixed to a plate 92 to which that surface of the contact bridge 22 facing the contact points is fixed. A modification is shown in the right hand side of Figure 2, in which that part corresponding to the part 82 has the reference numeral 83 and possesses an inwardly extending flange 85, to the inner edge of which there is fixed a cylindrical part 87 which is connected to one end of the bellows 48. The bellows 48 contains the actuating rod 52, which is firmly connected to the plate 92 in a manner not shown.

It can be seen from Figure 2 that the spring 54 of Figure 1 has been dispensed with. The cohesion force arises exclusively from the resilient force of the bellows together with the surrounding atmosphere.

By virtue of the arrangement of the insulating pipes inside the two parts 76 and 78 which border the arcing chamber 14, a relatively small and compact structure is attained such that the already small structure of Figure 1 can be further reduced. Figure 3 shows a similar embodiment to that of Figure 1. In this case, the supply line and return line are disposed at an acute angle to each other in the direction of the actuation movement, with the result that the fixing element 40 must be modified such that the support tubes 36 and 38 are now fixed inclined into the plate 102 which upperly closes the container 100. With regard to the arrangement of the container and the fixing of the bellows, together with the mounting of the contact bridge on the bellows, these corresponds to the embodiment of Figure 2, nameiy that arrangement thereof which lies to the right of the centre line.

Claims

1. A vaccum switch comprising two fixed contacts lying within a vaccum chamber, and connected to a supply line and a return line respectively, said contacts being bridgeable by means of a contact bridge movable by means of an actuating rod wherein the supply line and return line are each surrounded by an insulating tube, and the contact bridge is supported on a bellows which surrounds the actuating rod.

2. A vaccum switch as claimed in Claim 1, wherein the ends of the insulating tubes which face away from the contact points are firmly connected to the supply line and return line, one end of a container defining the vaccum chamber is connected to the insulating tubes, the end of the bellows facing away from the contact points is connected in a vaccum-tight manner to the other end of the container.

3. A vaccum switch as claimed in Claim 2, wherein the bellows also surrounds a compression spring which acts on the bellows and contact bridge in a direction to close the switch.

4. A vaccum switch as claimed in any one of the preceding Claims, wherein the contact bridge comprises two parts firmly connected to each other, of which the first is connected to the bellows and to the actuator, and the second carries the contacts of the contact bridge.

5. A vaccum switch as claimed in Claim 4, in which the first part is in the form of a plate, connected to the bellows and in which the second part is secured to the inner surface of the plate.

6. A vaccum switch as claimed in any one of the preceding Claims, in which the supply line and return line lie parallel to each other, the vaccum chamber is defined by a substantially cylindrical container and the supply line and the return line are led into the container through the insulating tubes at the first end of the container, the other end of the container being connected to the bellows which projects into the container, such that the container covers both the contact points and the bellows.

7. A vaccum switch as claimed in any of Claims 1 to 5 in which the supply line and return line are aligned with each other, and the vaccum chamber is defined by a container which comprises three cylindrical regions of which two, surround the insulating tubes and are coaxial with one another and with the supply line and the return line and in which the third part extends with its axis perpendicular to the axes of the two first parts and surrounds the bellows, such that the container is of overall Form.

8. A vaccum switch as claimed in any preceding Claim, in which the insulating tubes are connected at their ends neighbouring the contact points to the supply line and return line, and the container is connected to those ends of the insulating tubes which face away from the contact points.

9. A vaccum switch as claimed in any one of Claims 1 to 5, in which the supply line and return line lie at an acute angle to one another.

1 0. A vaccum switch constructed substantially as herein described with reference to and as illustrated in Figure 1, Figure 2, or Figure 3 of the accompanying drawings.