Ganged Push-Button Switch

The present invention relates to a construction of ganged push-button switch and, more particularly, to a less expensive ganged push-button switch having a simple construction which permits repair or renewal of switch blocks from the operation side, i.e. front side, of the ganged push-button switch.

As will be explained in detail later with reference to attached FIG. 1, a conventional ganged push-button switch requires a special jig for bending fixing claws used to fix respective switch blocks to a frame. Thus, for assembling different ganged push-button switches having different pitches of mounting of switch blocks, it is necessary to use different jigs suited for different pitches. In addition, if one or more of the switch blocks have failed, it is necessary to bend back the fixing claws using a special jig for demounting the switch blocks. Then, the repaired switch blocks or new switch blocks are mounted and fixed again by bending the fixing claws again. This mounting and demounting operation has to be made with greatest care, for otherwise the claws may be broken due to repeated bending and stretching. The ganged push-button switch as a whole becomes unusable, even by a breaking of only one of the fixing claws.

Accordingly, an object of the invention is to provide a novel ganged push-button switch free from the above-described problems of the prior art.

To this end, according to the invention, there is provided a ganged push-button switch assembly having a plurality of push-button switches each of which having an operation rod movably inwardly of the switch to the inner side of a latchable position, the assembly having an interlocking plate common for said switches, each of the switches having a casing fitted in an opening formed in a metallic frame common to the switches and a cover member in which the operation rod is slidable, wherein the improvement comprises that the casing has a pair of resilient arms adapted for engagement with the opening of the frame, and that the cover member has a pair of retainers engageable with the casing and is provided at its portion projected forwardly from the frame with a groove which receives an engaging portion projected from the interlocking plate.

The above and other objects, as well as advantageous features of the invention will become clear from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of a conventional ganged push-button switch assembly;

FIG. 2 is an exploded perspective view of a ganged push-button switch assembly constructed in accordance with an embodiment of the invention;

FIGS. 3(a) and 3(b) are front elevational views of the ganged push-button switch assembly as shown in FIG. 2; and

FIG. 4 is a side elevational view of the ganged push-button switch assembly as shown in FIG. 2.

Before turning to the detailed description of the preferred embodiment, an explanation will be made as to a typical conventional ganged push-button switch assembly, in order to facilitate the understanding of the problems of the prior art and, hence, the advantage of the present invention.

Referring to FIG. 1, a typical conventional ganged push-button switch has a substantially U-shaped frame 21 made of a metallic plate and provided with a multiplicity of recesses 21a each receiving a switch block 22. An interlocking cam plate 23 is disposed in relation to each switch block 22. Each recess 21a is provided with fixing claws 21c which are plastically bent to fix the associated switch block in the recess 21a of the frame 21.

Thus, in assembling this conventional ganged push-button switch, it is necessary to use a special jig for bending the claws 21b, for fixing the switch blocks 22 in the U-shaped frame 21. For assembling a plurality of ganged push-button switch assemblies having different mounting pitches of the switch blocks, it is necessary to prepare a plurality of jigs suited for these pitches. In the event of a failure in one or more switch blocks of the switch assembly, it is necessary to demount the failed switch block or blocks and to mount the repaired switch blocks or new switch blocks on the frame again. To this end, it is necessary to straighten or stretch the fixing claws employing a special jig to permit the demounting of the switch blocks and to bend the fixing claws again after the mounting of the repaired or new switch blocks. This work has to be done with greatest care, for otherwise the fixing claws may be broken due to repeated bending and straightening. The ganged push-button switch assembly as a whole becomes unusable even by a breaking of only one of the fixing claws.

This problem is completely overcome by the present invention, as will be understood from the following description of a preferred embodiment taken in conjunction with FIGS. 2 to 4. Referring to these Figures, a reference numeral 1 denotes an operation rod made of a synthetic resin and provided with a projection portion 1a for engaging an interlocking plate 2. Also, upper and lower recesses 1b, are formed in the operation rod 1 so as to receive movable contacts 3,3. A reference numeral 4 designates a casing also made from a synthetic resin and provided with an opening 4a for receiving the operation rod 1. A pair of resilient arms 4b,4b are formed on opposing walls of the casing 4. Also, on another pair of opposing walls of the casing 4, are formed a pair of projections 4c and 4c. Each resilient arm 4b is provided with an abutment 4d and a tab 4e.

A cover member 5 made of a synthetic resin has an opening 5a for receiving the operation rod 1, a groove 5b for receiving an engaging portion 2a of the interlocking plate 2, a recess 5c for receiving a coiled spring, spaced retainers 5d, 5d and a flange 5f provided with a cut-out portion 5e in which the tab 4e of the resilient arm 4e is placed. Each retainer 5d is provided with an engaging opening 5g. A reference numeral 6 designates a resetting coiled spring, 7 denotes a fixed contact provided on the bottom of the switch case 4, and 8 denotes a coiled spring for biasing the interlocking plate in one direction. A metallic frame 9 is formed by punching a blank from a metal sheet and then suitably bending the punched blank, and is provided with rectangular opening 9a for receiving respective switch blocks.

The ganged push-button switch assembly of this embodiment is assembled in the following procedure. After fixing the fixed terminals 7 in the casing 4, the resetting coiled spring 6 is inserted into the casing 4 and, thereafter, the operation rod 1 with the movable contacts 3,3 fitted in the recesses 1b,1b thereof is inserted in the casing. Thereafter, the cover member 5 is fitted to the casing 4. Then, after insertion of the operation rod into the opening 5a in the cover member 5, the retainers 5d,5d are brought into engagement with the projections 4c,4c of the casing 4, thus completing the assembling of one switch block. The switch block is then fitted in the corresponding rectangular opening 9a of the frame 9, so that the switch block is fixed by the engagement between the resilient arms 4b,4b of the casing 4 and the flange 5f of the cover case 5.

Subsequently, the interlocking plate 2 is secured to the frame 9 mounting the switch blocks. As will be seen from FIG. 3(a), the interlocking plate 2 is fitted from the front side of the frame 9 such that the engaging portion 2a of the interlocking plate 2 is positioned in the groove 5b of the cover case 5, with the coiled spring 8 disposed between the engaging portion 2a and the recess 5c of the cover member 5 as shown in FIG. 3(b).

In this state, the engaging portion 2a of the interlocking plate 2 can be brought into and out of engagement with the projection portion 1a of the operation rod 1. The assembling of the ganged push-button switch is thus completed.

The demounting of the switch block, if necessary for repair or renewal, can be made in a manner explained hereinunder. First of all, the coiled spring 8 urging the interlocking plate 2 is detached and the latter is moved to the position shown in FIG. 3(a). In this state, the interlocking plate 2 can be detached from the assembly. Thereafter, the tabs 4e,4e on the resilient arms 4b,4b of the switch case 4 positioned in the cut-out portion 5e are deflected inwardly to disengage the abutments 4d,4d of the resilient arms 4b,4b from the frame 9. In this state, the switch block can be drawn out simply by being pulled forwardly.

As has been described, according to the invention, there is provided a ganged push-button switch assembly which permits an easy mounting and dismounting to and from the frame and in which the interlocking plate is mounted at the front side to facilitate the mounting and demounting thereof. In this ganged push-button switch assembly, therefore, the mounting and demounting for repair or renewal of the switch blocks can easily be made from the front side of the mounting panel or the like. In addition, this ganged push-button switch assembly having simple construction can be produced at a reduced cost of production.