GB2183913A

GB2183913A - Electrical rocker switch

Info

Publication number: GB2183913A
Application number: GB08530104A
Authority: GB
Inventors: Arthur Bates
Original assignee: BSR
Current assignee: BSR
Priority date: 1985-12-06
Filing date: 1985-12-06
Publication date: 1987-06-10
Also published as: GB8530104D0; GB2183913B

Abstract

An electrical rocker switch has a base (17) apertured to receive cable 47 receiving members (21A) held in the base of the cover (30) which supports a pivoted rocker (43) held in place by a retainer (45). The rocker carries a spring loaded plunger (44) passing through an aperture (41) in the cover. The cable receiving members (21A) support opposing fixed contacts (23, 24) and a pivot (22) for the moving contact (25). The latter is mounted in a channel of a plastics support (27) received in grooves (29) of the base so that longitudinal movement of contact and support is prevented. The support (27) is pivoted by the plunger (44) or, on contact welding, by rocker portions (51). A second set of contacts can be provided in a second base portion (18), and plural rocker switches mounted in a common support. <IMAGE>

Description

SPECIFICATION Electrical switch This invention relates to an electrical switch of the rocker type more particularly but not exclusively, to sucn a switch intended to be used in a so-called grid range system in which a number of switches which may be of different ratings and different circuit functions, are mounted on a mounting grid which is housed within a box, the box being provided with a suitably apertured cover.

A conventional form of rocker switch has a moving contact which is formed from strip material which locates upon a pivot edge defined on a connecting member and forms an electrical connection therewith. The strip material forming the contact is provided with lateral ears which locate in grooves formed in an insulating support, or is provided with recesses in which locate guide portions which act to provide endwise location of the contact. Both forms of construction require that the contact is formed from strip material which has an overall width which is wider than is required to carry the rated current of the switch.Moreover, the contacts are usually formed from a length of stock strip which is cut transversely to its length, to form the individual strips and it is convenient to weld contact material in the form of a longitudinal bead along one edge of the stock strip before it is cut to form the individual strips. Where the strips forming the individual contacts are of a substantial overall width there is firstly a substantial waste of base material and of course corresponding waste of the expensive contact material. So far as the contact material is concerned it has therefore been the practice to provide individual contacts which process whilst saving on contact material does cost more to effect.Furthermore, in order to satisfy the requirement that the electrical circuit through the switch can be broken even in the event that the spring in the actuating mechanism breaks or becomes ineffective, it is necessary to provide further ears or projections on the contact which can be engaged by a manually actuated part of the actuating mechanism, to enable the contact to be moved. The provision of such further ears or projections if not requiring additional material, increases the cost of manufacture of the contact.

A further problem occurs during the assembly of the switch. The usual form of switch includes a base which defines a number of shaped recesses to receive and locate connecting members and the associated cable receiving members, and a cover for the base which is provided with an aperture through which extends a part of the actuating mecha nism. The conventional method of assemoly is to locate the base in a jig with the open ends of the recesses uppermost, to position the coacting members and cable receiving members in the respective recesses together with the moving contact, to locate the actuating mechanism in position and then to locate the cover. Following the location of the cover the assembled switch is turned over to allow retaining screws or rivets to be inserted to secure the base to the cover.The need to turn the assembled switch over to allow the retaining screws or rivets to be fitted has to be carefully carried out otherwise parts of the switch may become displaced and moreover, it is not easy to automate such an operation.

The object of tne invention is to provide an electrical rocker switch in a simple and convenient form.

According to one aspect of the invention an electrical rocker switch includes a moving contact formed from strip conductive material, a support for said contact, said support being formed from a plastics material and defining a channel to receive said contact, means defined by the support and contact to locate the support and contact against relative movement in the direction of the length of the contact, and further interengaging means defined by the support and a switch base, to provide location of the support relative to the base in said direction.

According to a further aspect of the invention an electrical rocker switch includes a base defining recesses for the reception of connecting members and associated cable receiving members, a pivotal moving contact, a cover for said base, said cover being engageable with said base to retain said connecting members and cable receiving members within the respective recessess, means for securing said cover to said base, and an actuating mechanism for said moving contact, said actuating mechanism passing through an aperture in said cover into engagement with said contact and a retaining member engageable with said actuating mechanism and said cover to retain the actuating mechanism relative to the cover.

In the accompanying drawings: Figure 1 is a perspective view of a switch in accordance with the invention mounted in a mounting grid, Figure 2 is an exploded view of one example of tne switch, and Figure 3 is a view to an enlarged scale of part of the switch seen in Figure 2.

Referring to Figure 1 of the drawings the switch generally indicated at 10, is shown to be mounted between a pair of spaced longitudinal members 11 of a mounting grid generally indicated at 12 and which in use, is adapted to be mounted in a box along with further grids, the box having a cover with apertures therein through which access can be gained to the actuating member 13 of the switch. It will be appreciated tnat the mounting grid may support a plurality of identical switches or the switches may be of different ratings and of different electrical configurations. It is also possible to mount other forms of electrical device such for example as indicator lamps.The switch is located by means of aligned cut-outs 14 in the members 11 and is secured to the members 11 by means of retaining members 15 which have angularly movable heads which can be passed through apertures 16 respectively. It will also be noted that the outer longitudinal edges of the longitudinal members are turned through substantially 90" to provide further location for the switch.

Turning now to Figures 2 and 3 the switch comprises a base 17 which is formed from electrically insulating material and within which is formed in the paticular example, a pair of elongated recesses 18 which are separated by an intervening wall 19. At the opposite ends of each recess there is defined a circular recess 20 the axis of which extends substantially normal to the general plane of the base.

The recesses 20 have communicating channels 21 which extend to the end walls of the base.

The recesses 20 serve to accommodate cable receiving members 21A which are of hoilow tubular form and which are provided with threaded side entries for the reception of cable securing screws in known manner. Each cable receiving member has associated therewith a connector member and these are of different shape depending on the duty which they are to perform. The example of switch is a two-way switch and the so-called common cable receiving member is provided with a strip which extends into the adjacent elongated recess 18 and is shaped to define a pivot 22 which is positioned substantially midway between the ends of the respective elongated recess.The recess 20 which is at the end of the elongated recess in which the pivot 22 is located carries a cable receiving member 21A to which is secured a connecting member 23 which extends over the adjacent end of the elongated recess and is spaced from the base wall thereof. The adjacent cylindrical recess 20 is occupied by a further cable receiving member 21A which carries a connecting member 24 of a more complex shape which extends transversely through an opening in the wall 19 into the recess 18 occupied by the pivot 22 and lies under the connecting member 23 adjacent the base wall of the recess. The connecting members 23 and 24 are provided with contacts formed from special contact material such for example as silver.

The other elongated recess is, in the particular example, not occupied but if for example the switch were a double pole single way switch both of the elongated recesses would be utilised.

The switch further includes a moving contact 25 which, as more clearly seen in Figure 3, is of elongated form and has aligned ears 26 extending laterally from the longer sides thereof. The contact 25 is carried by a support 27 which is formed from thermoplastics material having a high softening temperature.

One side of the support is of channel form to accommodate the contact 25, the ears 26 being located within recesses formed in the side walls of the channel. The ears 26 and the recesses form interengaging means to locate the contact 25 relative to the support against relative endwise movement. If desired however the contact could be provided with recesses which engage with projections on the support.

The side walls of the support are provided with projections 28 respectively which locate in corresponding grooves 29 formed in the intervening wall 19 of the base and the respective outer wall. The projections 28 and the grooves 29 form further interengaging means which act to locate the support relative to the base against endwise movement thereof. When the contact and support are located in position, the contact is supported by the pivot 22 and one end of the contact extends beyond the support and is provided with contact material for engagement with one or the other of the contacts carried by the connector members 23, 24.

The assembly of the parts of the switch thus far described, can be carried out very simply with the base located for example on a jig, the various items simply being placed in position. The parts are retained in position within the base by means of a cover 30 which can be located on the upper surface of the base. Conveniently the intervening wall of the base defines a projection 3 1 which locates within a complementary recess in the underside of the cover and the cover has a projection (not shown) which extends downwardly and engages with the portion of the contact 24 which passes through the intervening wall 19. Moreover, the cover is provided with prosections which locate in the channels 21 respectively so that once it is correctly located on the base there is no chance of relative movement once retaining members 32 have been located in position. The retaining members 32 are of cylindrical form and define a pair of spaced flanges 33, 34, the flange 33 locating against a recessed ledge 35 formed in the end face of the cover and the flange 34 engaging with a recessed ledge 36 formed in the end face of the base. The cover and base are provided with open ended slots to allow the passage of the intermediate portion of the retaining member and conveniently the flanges are an interference fit with the complementarily slotted portions of the cover and base to assure retention of the retaining members. At their lower ends the retaining members are of bulbous form to enable a plate-like member 37 to be engaged therewith, the plate-like member 37 having apertures 38 aligned with the cable receiving members 21.Moreover, at their upper ends the retaining members are extended to define rectangular shaped heads 39 which can be passed through the complementarily shaped apertures 16 in the longitudinal members 11 of the mounting grid. The heads can then be rotated through 90" to retain the switch mechamism in position.

The cover 30 in its face remote from the base, defines a generally rectangular recess 40 in the base wall of which is formed two apertures 41 which are aligned with the elongated recesses 18 but which are of a substantially smaller length. The apertures 41 are so positioned as to allow part of the switch actuating mechanism shown generally at 42, to pass therethrough and to engage the upper surface of the carrier 27. The actuating mechanism comprises a pivotal rocker 43 in which is mounted a spring loaded plunger 44, the plunger extending through the respective aperture 41 to engage the upper surface of the carrier. The rocker is retained in position by means of a retaining member 45 which is of generally open rectangular form with its internal side walls defining surfaces for engagement by complementary pivot surfaces 46 formed on the rocker 43.The retaining member 45 locates within the recess 40 and is secured therein by retaining elements 47, the elements 47 being integrally formed with the retaining member and passing through complementary apertures 48 in the base wall of the cover, the retaining elements 47 being sufficiently resilient to allow them to snap into an interference relationship with surfaces conveniently defined in the thickness of the material forming the cover 30.

The continued assembly of the switch once the retainer members 32 have been placed in position, is extremely simple and can be effected without having to remove the base from the jig or other locating device. The switch as described therefore is readily capable of automatic assembly and even if it is assembled by hand, the assemoly process is greatly facilitated over the conventional arrangement of switch.

It will be noted that the carrier 27 is provided, on its upper surface, with projecting portions 49, the purpose of these being to permit the switch to be operated at least to break the electrical circuit through the switch, in the event that the spring loading the plunger 44 breaks or becomes inoperative. The projections 49 would be engaged by faces 51 of rocker 43 to cause pivotal movement of the support.

The contact 25 as illustrated, is provided with contact material 50 on the opposite faces of its projecting portion, the material be ing applied as a bead to the stock strip from which the individual contacts are formed. The projections 26 are very small so that in the production of the individual contacts 25 very little of the stock material is lost to waste and consequently also very little of the expensive contact forming material.

The construction as described can be used in the production of an electrical switch of the domestic type. In this case the so-called cover 30 would be formed in the fashion of a substantially square face plate and provided with apertures for the reception of screws to secure the face plate to a wall box. The face plate would have at least a pair of further apertures to receive screws to secure the face plate to the base 17. Moreover, the retaining member 45 would be shaped to cover the further apertures.

Claims

1. An electrical rocker switch comprising a base defining recesses for the reception of connecting members and associated cable receiving members, a pivotal moving contact, a cover for said base, said cover being engageable with said base to retain said connecting members and cable receiving members within the respective recesses, means for securing said cover to said base, an actuating mechanism for said moving contact, said actuating mechanism passing through an aperture in said cover into engagement with said contact and a retaining member engageable with said actuating mechanism and said cover to retain the actuating mechanism relative to the cover.

2. A switch according to Claim 1 in which the means for securing the cover to the base comprises a pair of retaining members engageable with the base and cover either through the cover or by lateral movement relative to the assembled base and cover.

3. A switch according to Claim 2 in which said retaining members comprise screws or cylindrical members having spaced flanges for engagement with recessed ledges formed on the cover and base.

4. A switch according to Claim 1 in which said actuating mechanism comprises a pivotal rocker and a spring loaded plunger carried by said rocker and engageable with said contact, said retaining member defining surfaces for engagement by complementary pivot surfaces on said rocker.

5. A switch according to Claim 4 in which said moving contact is formed from flat strip material and is mounted on a pivotal support formed from plastics material, one of said connecting members being shaped for engagement by said moving contact, and said plunger engaging said pivotal support.

6. A switch according to Claim 5 in which said pivotal support and said pivotal rocker define interengageable elements whereby pivotal movement of the rocker will impart pivotal movement to the support in the event of failure of said spring.

7. A switch according to Claim 6 in which said pivotal support defines a channel to ac commodate said strip material, the side walls of the channel and the longer sides of the strip defining interengageable means to locate the strip in the channel against movement in the direction of the length of the strip.

8. A switch according to Claim 7 in which said pivotal support defines outwardly extending projections which locate in slots formed in side walls defined by the base, said slots extending generally at right angles to the plane of the strip.

9. A switch according to Claim 5 in which said strip is provided with a bead or beads of contact material for co-operation with a contact or contacts carried by the other connecting member or members.

10. An electrical rocker switch comprising a moving contact formed from strip conductive material, a support for said contact, said support being formed from a plastics material and defining a channel to receive said contact, means defined by the support and contact to locate the support and contact against relative movement in the direction of the length of the contact, and further interengaging means defined by the support and a switch base, to provide location of the support relative to the base in said direction.

11. A switch according to Claim 10 in which said means comprises interengaging projections and recesses on the longer sides of the moving contact and the side walls of the channel.

12. A switch according to Claim 10 or Claim 11 in which said interengaging means comprises outwardly extending projections on the side walls of the support, and grooves formed in spaced walls defined by the base.

13. An electrical rocker switch comprising the combination and arrangement of parts substantially as hereinbefore described with reference to the accompanying drawings.