GB2306676A

GB2306676A - Meter switches

Info

Publication number: GB2306676A
Application number: GB9522284A
Authority: GB
Inventors: Neil Rothwell
Original assignee: Siemens Measurements Ltd
Current assignee: Siemens Metering Ltd
Priority date: 1995-10-31
Filing date: 1995-10-31
Publication date: 1997-05-07
Anticipated expiration: 2015-10-31
Also published as: AU721585B2; EP0772050B1; AU7044796A; DE69627449T2; EP0772050A1; GB2306676B; IL119395A0; ZA968443B; GB9522284D0; DE69627449D1

Description

2306676 IMPROVEMENTS IN OR RELATING TO METER SWITCHES This invention

relates to electricity meter switches and to electricity meters which embody them.

More especially, but not exclusively, it relates to switches for modular electricity meters of a kind described in our copending British patent application numbers 9509304.3 (F21093), 9501772.9 (F21069), and 9424461.3 (F21667), which include a mains isolatine switch.

Modular meters of the kind described as aforesaid, comprise a basic meter module which includes a mains electricity isolating switch effective to isolate a consumer circuit from a supply circuit. The switch may be manually operated and/or it may be operated by an actuator in an 'add-on' module, fitted to the basic module to extends its functionality,. Thus, as explained in our co-pending patent applications, the basic module may include for example a manually operated switch and be converted to a prepayment meter by the addition of an 'add-on' module, which is arranged to receive electricity credit tokens and which includes a switch actuator operable automatically when credit is exhausted to cause the switch to disconnect a consumer frorn an electricity supply.

It is apparent that a switch for modular and other electricity meters should be robustly constructed and yet be simple and comparatively inexpensive to fabricate.

One object of this invention therefore is to satisfy these requirements.

0 According to the present invention a switch assembly for an electricity meter comprises two parts, one of which parts includes a fixed contact and a meter output terminal and the other of which parts includes a moving contact and a meter input terminal, the movine, contact being coupled to the input terminal via a conductive spring on which it is supported and which serves in use both to carry switch current and to bias the moving contact towards the fixed contact, and via a meter shunt adapted so as to receive in use, sensor conductors so that current supplied via the switch from the input terminal to a consumer via the output terminal can be sensed for measurement purposes.

The switch assembly may form a part of a single pole switch.

The shunt may comprise strip metal to which a strip metal input terminal and a strip metal spring, are electrically connected, in spaced apart relationship.

The spring may include between the movincr contact and the shunt a narrowed portion to facilitate spring flexure without fracture at a Junction with the shunt.

The output terminal rnay be formed from metal strip, one end of which is arranged to serve as the output terminal and the other end of which is adapted to define an electrical socket connector for receiving a complimentary plug of a meter 'add-on' module, the fixed contact being supported by the metal strip at a position intermediate between its ends.

The input and output terminals may be fabricated from flat copper strip material, the,hunt and the spring may be fabricated C from copper alloy strip material, not necessarily of the same composition, and the fixed and moving contacts may comprise silver alloy material.

The input and output terminals may be supported in spaced apart relationship within a meter housing, so that flat strip material of respective terminals lies co-planar, both terminals being bent orthogonally of this plane so that the moving contact aliens with the fixed contact to facilitate switch operation and with a switch actuator which in use is used to effect switch operation against the biasing force of the spi-inal.

0 C1 The flat sarip material of the output terminal may be formed so that the socket connector extends in planes generally parallel with the output terminal.

One embodiment of the invention will now be described by way of example only with reference to the accompanying drawin-s, in which, FIGURE 1 is a aenerally schematic perspective view of parts tn for a single pole electricity meter switch; FIGURE 2 is a perspective view of the parts shown in Figure 1 from a different angle; FIGURE 3 is a perspective view of the parts shown in Figures 1 and 2, assen-ibled in a ineter housine, and shaded for ease of identification, and FIGURE 4 is a perspective view of the parts shown in Figures 1, 2 and 3, assembled in a meter housing which includes a switch actuator.

Referrina now to the drawinas, wherein corresponding parts of the various Figures bear, as appropriate, the same numerical desianation, a contact assembly for a single pole meter switch comprises two parts 1 and 2. The part 1 includes a flat copper metal strip input terminal 3, which is bent orthogonally and which is electrically and mechanically connected by a means of brazing points 4 to a flat copper alloy shunt 5. Tile shunt 5 is connected by brazing points 6 to a copper alloy leaf spring 7 which supports a movin. switch contact 8. To facilitate brazing of the points 4 and 6, the parts may first be 'part pierced', so that they mutually locate. Although in this example, brazing points are used, to effect electrical connection, it will be appreciated that in alternative embodirnents the parts may be welded, hard soldered or screwed together so as to provide the necessary electrical connection, and mechanical strenath. The shunt 5 includes arooves 9 to which conductors are connected which couple the shunt to a measurement circuit (not shown). Grooves 10 are also provided in which conductors are soldered which serve to provide power for other part.,; of the electricitv meter.

In order to facilitate flexure of the spring 7, a narrowed 0 neck 11 is formed betvveen the shunt 5 and the moving contact 8.

0 The movine contact 8 is arranged to co-operate with a fixed contact 12. k, .,lilcli is supported on a copper strip output terminal 13 which is bent orthogonally so that the fixed and moving contacts 12 and 8 respectively align. Strip material from which the output terminal 13 formed is provided at an end thereof remote from the terminal 13, with a spring connector 14, as 0 shown in Ficure 2, which, as will hereinafter be explained, serves to provide electrical connection via a complimentary plue, part C1 (not shown) of an 'add-on' module (not shown).

As can be best be seen in Figure 3, the terminals 3 and 13 are arranged to lie flat in a housing body 15 so that they are mutually parallel and lie in substantially the same plane. In use of a meter of which the housing forms a part, input and output conductors are introduced through apertures 16 and 17 C> respectively in the housing 15 and clamped into position by C1 means of screws 18 against the input and output terminals 3 and 13 respectively. Apertures 19 and 19a in the housing are provided for input and output neutral conductors respectively, which are secured by means of clamping screws 20. Connection of the neutral conductors is not central to the present invention, since the rneter incorporates single pole switching only.

As shown in Ficure 4, a mechanical switch actuator 21 is provided which is arranged to effect switch operation so as to open or close the contacts 8 and 12 against the biasing force provided by, the leaf spring 7. Additionally the switch may be operated by an actuator (not shown), which is contained in an 1 add-on' niodule (not shown) fitted to the basic meter module to extend functionality,, as described in our co- pending patent applications.

The actuator (not shown) is arranged to operate in the direction of an aii-o, 22 so as to rnake contact with a switch operating rneniber 23 which operates through a lever 24 to effect c -- switch operation in a manner similar to operation as effected by the switch actuator 21.

Althou.h the 'add-on' module and parts associated 0 therewith are not described in detail, they are described in our co-pending patent applications to which attention is directed.

C1

Claims

CLAINIS

1. A switch assembly for an electricity meter comprising two parts, one of which parts includes a fixed contact and a meter output terminal and the other of which parts includes a moving contact and a meter input terminal, the moving contact being coupled to the input terminal via a conductive spring, on which it is supported and which serves in use both to carry switch current and to bias the moving contact towards the fixed contact, and via a meter shunt adapted so as to receive in use, sensor conductors so that current supplied via the switch from the input terminal to a consumer,ia the output terminal can be sensed for measurement purposes.

2. A switch assembly as claimed in Claim 1, which forms a part of a sin]c pole switch.

c

3. A switch a,,,,ei-nbly as claimed in any preceding Claim, wherein the slitint comprises strip rnetal to which a strip metal input terminal and a strip rnetal spring are electrically connected, spaced apart by the shunt.

4. A ssvItch assembly as claimed in any preceding Claim, Z> ",herein the spring includes between the moving contact and the C1 shunt a narrowed portion to facilitate spring flexure.

C1 A-

5. A switch assembl as claimed in any preceding Claim, y c wherein the output terminal is formed from a metal strip, one end of which is arranged to serve as an output terminal connector and the other end of which is adapted to define an electrical socket connector for receiving a complimentary plug of a meter 'add-on' module, tile fixed contact being supported by the metal strip at a position intermediate between its ends.

6. A switch assembly as claimed in any preceding, Claim, wherein the input and output terminals are fabricated from flat copper strip material; the shunt and the spring are fabricated 0 from copper alloy strip material and the fixed and moving contacts comprise silver alloy material.

7. An electricity rneter including a switch assembly as claimed in any, preceding Claim, \vherein the input and output terminals are supported in spaced apart relationship within a meter housing so that flat strip material of respective terminals lies co-planar, both terminals being bent orthogonally of this plane so that the rnovina contact aligns with the fixed contact to facilitate switch operation and all-ns ",Ith a switch actuator which in use is used to effect switch operation a-ainst the blasin. force of the spring c c C"

8. A switch assembly as hereinbefore described with reference to the accompanying di-as,,iii.s.

9. An electricity meter including c in any preceding Claim.

a switch assembly as claimed p