GB2310084A - Electrical switches - Google Patents

Abstract

An illuminatable electrical switch comprises a body unit 17 and a lamp and switch unit 19. The lamp and switch unit has circuits for the lamp 77 and for the switch 89 which lead to a single connector 29. For ease of lamp insertion and removal, interengageable bayonet formations are provided on the body unit and on the lamp and switch unit. The body unit has a bezel 35 and a spring loaded plunger 65 which actuates the switch and which has a cap 71 that protrudes, or has a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, the protruding portion of the lens cap having a tapered external peripheral surface that seats against a tapered internal peripheral surface of the bezel to prevent removal of the lens cap through the bezel. To prevent removal of the bezel from the body unit, the bezel is provided with projections (61, Fig. 14) that fit into channels 51 of the body unit and have formations 53,63 that snap engage to hold the bezel in place. A cup 37 fits onto a threaded tail region 39 of the body unit and when held in place by a nut 41 traps a mounting panel between itself and the bezel 35 and also prevents movement of the projects 61.

Description

IMPROVEMENTS IN ELECTRICAL SWITCHES The present invention relates to illuminatable electrical switches and to wiring systems incorporating such switches.

A pushbutton assembly for a switch having a plunger which reciprocates in a cup-shaped cavity of a body is disclosed in US Patent No 4463237. The body has an externally threaded sleeve which can be passed through an aperture in a mounting panel and secured by tightening a retaining nut.

Illuminated push button switches whose major working parts, other than the electrical parts, are of moulded plastics material are widely used in, for example, gaming or amusement machines to enable a user to control operations of the machine, for example the rotation of a symbol-carrying wheel in the machine past a viewing window.

It is an object of the invention to provide an illuminated electrical switch which is easier and more rapidly fitted to its intended wiring, and/or which is more tamper-resistant.

It is a further object of the invention to provide an electrical switch having a plunger and a bezel which are tamper-resistant.

In one aspect the invention provides an illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the lamp and switch unit has circuits for the lamp and/or for the switch which lead to a single connector.

In another aspect the invention provides an electrical wiring system comprising a plurality of illuminatable electrical switches as aforesaid, a wiring loom, and branches leading from the loom to respective switches and terminating at a single connector which mates with the connector of the respective lamp and switch unit. For simplicity and speed of fitting, the wires of the loom branches are preferably connected to the respective single connectors by insulation displacement.

In a third aspect of the invention there is provided a kit of parts for forming an electrical wiring system comprising a plurality of illuminatable electrical switches as aforesaid, a wiring loom having branches for the switches terminating at single connectors, said single connectors being engageable with the connectors of the lamp and switch units to connect the lamp and the switch thereof to the loom.

The invention also provides an illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein interengageable bayonet formations on the body unit and on the lamp and switch unit removably position the lamp and switch unit on the body.

The switch is preferably operable by depression of a plunger in the body unit to actuate the switch of the lamp and switch unit, the lamp fitting within the plunger so that when it is illuminated, its light passes to the exterior through an end of the plunger.

The invention yet further provides an illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the body unit has a bezel and has a spring-loaded plunger which when depressed becomes displaced from a rest position and actuates a switch of the lamp and switch unit, the plunger having a cap that protrudes, or having a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, the protruding portion of the lens cap having a tapered external peripheral surface that seats against a tapered internal peripheral surface of the bezel to prevent removal of the lens cap through the bezel.

In a further aspect, the invention provides an illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the body unit has a bezel and has a spring-loaded plunger which when depressed becomes displaced from a rest position and actuates a switch of the lamp and switch unit, the lamp being arranged so that its light is viewed through the plunger, and the plunger having a cap that protrudes, or having a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, wherein the bezel is a separate component that clips to the body unit.

The invention also provides an electrical switch which comprises: (a) a body having a head portion defining a chamber which contains a reciprocable plunger and a tail portion which is externally threaded; (b) a bezel which attaches to the body by projections which extend along the outside of the head portion and which have formations which snap engage with formations on the head portion to hold the bezel in position on the body; (c) a cup which fits onto the tail portion of the body and surrounds the head portion of the body and impedes movement of the projections which would otherwise permit the formations to disengage; and (d) a nut which fits onto the threaded tail portion of the body to hold the cup in place.

In the switch as aforesaid, the head preferably has a sidewall formed with longitudinally directed channels into which the projections of the bezel fit.

For ease of cutting a panel opening for the switch, the projections do not protrude outwardly from the sidewall or sidewalls of the head. The bezel may be formed with three or four such projections, and the head may be of any desired outline, e.g. square, rectangular, triangular, oval or circular. The dimensions of the head and of a portion of the plunger that fits within the head are preferably such that the greater part of their length is behind the bezel. When the switch is mounted to a panel, these components are behind the panel for the greater part of their length.

Various embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a front view of part of an amusement machine showing a push switch mounting panel provided with illuminated push switches according to one embodiment of the invention; Figure 2 is a view from the interior of the machine showing the push switch mounting panel, the illuminated push switches and part of the associated electrical wiring; Figures 3 to 7 are respectively an isometric front view, a plan view, an isometric rear view, a partially exploded view and a view in partial section of a first form of illuminated push switch according to the invention, which when viewed from the front is rectangular and has a rectangular push button;; Figure 8 is a view in section of a body unit forming part of the illuminated push switch of Figures 3-7; Figures 9-11 are exploded views of a lamp and switch unit forming part of the illuminated push switch of Figures 3-7, the views being from the rear, in plan and from the front respectively; Figures 12 and 13 are alternative forms of circuit provided on a board forming part of the lamp and switch unit of Figures 8-10; Figure 14 is a view of a bezel and body which form part of the illuminated push switch of Figures 3 to Figures 15 and 16 are front and side views of a second embodiment of the illuminated push switch with a second form of lamp and switch unit and Figure 17 is a sectional view thereof; and Figure 18 is an isometric front view of a further form of the illuminated push switch in which a round push button is provided within a square bezel, Figure 19 is a rear isometric view of a bezel, and Figure 20 is a rear isometric view of a lens cap, both of which form part of the switch of Figure 18.

The present invention concerns illuminated push switches which are fitted, for example, to amusement machines, vending machines, arcade games machines, machines ridden by children, control panels for vehicles, industrial machines, telecommunications installations and the like to provide a control signal to the machine, vehicle or other installation. Thus Figure 1 is a front view of an amusement machine having a control panel 10 provided with a number of illuminated push switches 12. As seen in Figure 2, a wiring loom 14 of the machine has branches 16 leading to each switch 12, each branch having a pair of wires for carrying lamp current and either a second pair of wires for a simple switch or three wires in the case of a change-over switch.It is therefore necessary to establish four or five electrical connections to each switch during the manufacture of the machine, and possibly additional "daisy-chain" connections to other switches or to other devices such as sensors or indicating devices. In the present form of loom and switch these connections are labour-intensive to provide both during manufacture of the loom 14 and during connection of the loom 14 to the switches 12. One problem with which the present invention is concerned is to provide an arrangement which takes less time to assemble and fit.

The lamps within the switches 12 need replacement from time to time. A present form of illuminated switch has a lamp and switch unit which is a removable snap fit in a body of the switch. However, the resistance of the snap fits are sometimes difficult to overcome, especially if the switch is located in a crowded part of the machine or is awkward to get at, and it has been appreciated that it would be advantageous to provide a switch construction in which the lamp and switch unit is easier to remove and refit.

Illuminated switches of the present kind are worked by a plunger which carries a lens cap. In the present switches, the lens caps are easy to remove from outside the machine, and a third problem with which the invention is concerned is to provide a switch construction in which this is made more difficult.

Customers often require the shape or colour of the bezel and/or the plunger to vary, and a further problem with which the invention is concerned is to provide a simple and inexpensive way in which this may be achieved whilst maximising the use of common parts.

These problems are solved in the switch unit of Figures 5-14 which comprises a body unit 17 and a lamp and switch unit 19 which fit removably together by bayonet pins 21 on the unit 19 which fit into a socket 23 formed at the back of the body unit 17. The twist and pull movement required to remove the lamp and switch unit 19 is easier and safer to perform than having to apply force to the unit 19 sufficient to unsnap it from the unit 17. Furthermore the wiring branches 16 each terminate at a single plug connector 27 which is a push fit within a socket connector 29 forming part of the unit 19.As the parts 27, 29 are mated together, pins 31 in the socket connector 29 are received in sleeves of the plug connector 27 leading to the individual wires of the loom branch, so that the connections for the lamp and for the switch are all established in a single operation which is faster and less error-prone than present arrangements in which separate connections for the individual wires are provided. Furthermore the plug connector 27, which is preferably of the insulation displacement connector type, is simpler and faster to fit to the wires of loom branch 16 than individual receptacles.

As is apparent from Figures 6 and 7, the body unit 17 comprises a switch body 33 to which is fitted a bezel 35, a cup 37 which surrounds the switch body and which is formed with an apertured base through which a threaded lower portion or tail 39 of the switch body 33 protrudes, and a retaining nut 41 which can be screwed onto the lower portion 39. In order to fit the switch into an aperture in the control panel 10, the body 33 is inserted into the aperture, the cup 37 is placed onto the body so that the panel 10 becomes sandwiched between the bezel 35 and the cup 37, after which the retaining nut 41 is fitted onto the lower portion 39 and tightened.As will be explained below, the bezel 35 fits onto or can be removed from the body 33 by relatively light force when the cup 37 is not in place so that the switch is easy to assemble, but is not removable when the cup 37 is in position around the body.

As best seen in Figure 14, the switch body 33 comprises a head which in this instance is square, but which may be of other shapes dictated by user requirements, e.g. circular, rectangular or triangular, and is defined by a base wall 45 and side walls 47. An opposite pair of the walls 47 are formed with upstanding anti-ingress flanges 49 and on their outer faces with rebated channels 51 provided at their upper ends with latch tongues 53. The base wall 45 is formed with an aperture leading into the threaded lower portion or tail 39 of the body whose lower end is formed with an inturned portion 55 and a returned portion 57 which defines a lamp-receiving socket. The internal edge of the bezel 35 is of the same shape as the head and has on its blind face at one pair of sides depending anti-ingress flanges 59 and at the other pair of sides fixing tabs 61 formed with sockets 63.Thus the body 33 and the bezel 35 are formed as separate parts which can be snap fitted together by locating the tabs 61 in the channels 51 and pushing the parts together until the tongues 53 locate into the sockets 63. The tabs 61 slide over the exterior of the body during fitting of the body and bezel together, and fit into the channels 51 on the exterior of the body so that they do not protrude outwardly beyond the side wall or walls. The anti-ingress flanges 49, 59 locate the bezel 35 longitudinally relative to the switch body 33 and also serve to impede ingress of unwanted material into the interior of the switch, although in this embodiment they are not continuous about the periphery of the head.One advantage of providing the bezel 35 as a separate component is that there may be provided a range of bezels 35 of different colour that can be fitted to a common switch body 33 to give different appearance according to user requirements. Another advantage is that the bezel 35 is easy to fit onto or remove from the head region of the body 17, but after the switch is mounted in position the projections 61 are behind the panel 10 (which may be of chipboard instead of the relatively thin sheet panel illustrated) or covered by the cup 37 which prevents them moving outwardly and hence prevents the bezel 35 from unsnapping from the head. For this reason unauthorised removal of the bezel from outside a machine to which the switch is fitted is rendered difficult.

Within the body 33 there is provided a captive plunger 65 comprising a plunger body 67, a legend plate 69 and a lens cap 71. The plunger body has a base portion 72 which fits within and is slideably guided by the inner surface of the lower portion 39, an enlarged head portion 73 which in this embodiment conforms to and is spaced slightly from the side walls 47, and an intermediate portion 75 being angled to provide a reflector for light from lamp 77. The major portion of the length of the head part of the body 33 and of the plunger 65 is located behind the bezel 35 and hence behind the panel 10 when the switch is in place. A leg or legs 74 depend from the base portion 72 of the plunger and when the plunger is in position within the body 33 protrude from the lower end of the portion 39 as can be seen in Figure 6.A coil spring 78 fits around the returned portion 57 of the switch body 33 and is in compression between inturned portion 55 and a rib 79 on the inner face of the base portion 72, thereby urging the plunger upwardly as viewed in Figure 7. The leg or legs 74 serve firstly to prevent the plunger 65 when it is inserted in the body 33 from being pushed out by the resilience of spring 78 and secondly to operate the switch of the lamp and switch unit 19 when the plunger 65 is depressed. The legend plate 69 and the lens cap 71 are carried by the upper end of the plunger 65 to which they may be a push fit. To hold the plunger captive and prevent the lens cap from being removed, the lens cap should be dimensioned so that it cannot pass through the aperture in the bezel.For this purpose, the side walls of the lens cap 71 may be bevelled as shown so that when the plunger is not being depressed, the lens cap 71 protrudes through a tapered mouth of the bezel 35 but cannot pass fully through the mouth of the bezel.

Using the two-part bezel and housing, the spring 78 and the plunger 65 can be inserted into the switch body 33, and the bezel 35 can be fitted into place to give the sub-assembly of Figure 8, after which the plunger is retained within body unit 17, can be depressed against the resistance of coil spring 78 and can return.

Referring to Figures 9-11, the lamp and switch unit comprises a combined lamp holder and circuit board 81, a box-like housing 83 and a cover 85. The front face of the housing 83 is formed with an aperture leading to sleeve 87 which fits into the socket formed by return portion 55 of the switch body 33, and the lamp 77 protrudes from the sleeve into the interior of the plunger 65 as shown in Figure 7. The front face of the lamp holder and circuit board carries a switch element which in this embodiment is in the form of a diaphragm switch 89 whose plunger (Figure 7) 91 is depressed by leg 74 as the plunger 65 is depressed in order to actuate the switch, the movement of the leg being indicated by an arrow, and the front face of the housing 83 being formed with an aperture 86 to permit the end of the leg 74 to pass into it.In this embodiment, the reverse face of the circuit board 51 carries a six-way connector block having the pins 31, although the connector block and the lamp holder and switch can, if desired, all be on the same face of the circuit board.

The cover 85 is provided at the back of the housing 83, has a formation which receives the six-way connector block and defines the socket 29, and is a snap fit to the housing.

In order to reduce the electrical power drawn from the supply and to improve the life of the bulb 77, in gaming machines the current to the bulb 77 is often pulsed. In practice, a number of bulbs within different push switches on the machine may be operated in time multiplexed manner from the same supply (not shown).

Illumination of the bulb at unwanted periods can be prevented by means of a diode electrically in series with the bulb 77 and which will pass current only when the applied electrical bias is of the right polarity. In known push switches, such diodes are provided as separate components which require attachment to the switch element and/or lamp housing. However, in the present embodiment of the push switch, the need to provide a separate diooe-carrying circuit board can be avoided. By appropriate wiring of the six way connector to connect to either pin F or pin E, the diode 93 may be connected into or may remain separate from the circuit through lamp 77, and correspondingly by wiring of the connector to either pin A or pin C, the diode 95 may be connected to or may remain separate from the circuit through switch 89.The circuit of Figure 13 is identical to that of Figure 12 except that the diodes are connected in reverse polarity.

In Figures 15-17, there is shown a second form of the illuminated switch in which the body unit 17 is as previously described, but the lamp and switch unit 100 is conventional except that it fits by means of bayonet pins to the body unit. The unit 100 comprises a lamp 77 and lamp holder of conventional construction, and a microswitch 102 having a plunger 104 which is actuated by leg 74 when the plunger 65 is depressed. The microswitch and lamp are connected to the wiring by conventional terminal tags 105 In Figures 18-20 there is shown a third form of the illuminated switch in which the bezel 110 is formed with a lid 111 in which is formed an aperture 112 of circular outline through which there protrudes a circular lens portion 114. It is therefore possible to provide a body unit having a head of one outline, e.g.

square, but provided with a lens cap region 114 defining a push button which is of a second outline e.g.

circular.

All the major components of the above switches, other than the lamp 77 and electrical components, are of moulded plastics material. It will be appreciated that various modifications may be made to the embodiments described above without departing from the invention, whose scope is defined in the accompanying claims. For example although the main use envisaged for the invention is for illuminated push switches, the body unit could be designed for another type of switch, for example a rotary switch or a sliding switch.

Claims (29)

1. An illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the lamp and switch unit has circuits for the lamp and for the switch which lead to a single connector.

2. The switch of claim 1, wherein interengageable bayonet formations on the body unit and on the lamp and switch unit removably position the lamp and switch unit on the body.

3. The switch of claim 1 or 2, wherein the lamp and switch unit comprises a circuit board one face of which carries a support and electrical connectors for the lamp, and the other face of which carries a terminal block of the single connector.

4. The switch of any preceding claim wherein the circuit board has first terminals which provide direct electrical connection to the lamp and switch and second terminals which provide electrical connection to the lamp and switch through diodes.

5. The switch of any preceding claim, wherein the body unit has a spring-loaded plunger which when depressed from a normal or rest position actuates a switch of the lamp and switch unit.

6. The switch of any preceding claim, wherein the body unit has a bezel, the plunger has a cap that protrudes, or has a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, the protruding portion of the lens cap having a tapered external peripheral surface that seats against a tapered internal peripheral surface of the bezel to prevent removal of the lens cap through the bezel.

7. The switch of claim 6, wherein the aperture in the bezel and the protruding cap or lens part are of the same shape as the bezel.

8. The switch of claim 6, wherein the aperture in the bezel and the protruding cap or lens part are of different shape to the bezel.

9. The switch of any preceding claim, wherein the body unit is provided with means by which said unit may be mounted in an aperture in a panel.

10. The switch of any preceding claim, substantially as hereinbefore described with reference to, or as illustrated in, Figures 3-14 or Figures 15-17 or Figures 18-20 of the accompanying drawings.

11. An electrical wiring system comprising a plurality of illuminatable electrical switches as claimed in any of claims 1 to 10, a wiring loom, branches leading from the loom to respective switches and terminating at a single connector which mates with the connector of the respective lamp and switch unit.

12. An electrical wiring system as claimed in claim 11, wherein wires of the loom branches are connected to the respective single connectors by insulation displacement.

13. A kit of parts for forming an electrical wiring system comprising a plurality of illuminatable electrical switches as claimed in any of claims 1 to 10, a wiring loom, having branches for the switches terminating at a single connector, said connectors being engageable with the connectors of the lamp and switch units to connect the lamp and the switch thereof to the loom.

14. An illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein interengageable bayonet formations on the body unit and on the lamp and switch unit removably position the lamp and switch unit on the body.

15. An illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the body unit has a bezel and has a spring-loaded plunger which when depressed becomes displaced from a rest position and actuates a switch of the lamp and switch unit, the plunger having a cap that protrudes, or having a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, the protruding portion of the lens cap having a tapered external peripheral surface that seats against a tapered internal peripheral surface of the bezel to prevent removal of the lens cap through the bezel.

16. An illuminatable electrical switch comprising a body unit and a lamp and switch unit, wherein the body unit has a bezel and has a spring-loaded plunger which when depressed becomes displaced from a rest position and actuates a switch of the lamp and switch unit, the lamp being arranged so that its light is viewed through the plunger, and the plunger having a cap that protrudes, or having a lens part which protrudes, through an aperture in the bezel when the plunger is at its rest position, wherein the bezel is a separate component that clips to the body unit.

17. An electrical switch which comprises: (a) a body having a head portion defining a chamber which contains a reciprocable plunger and a tail portion which is externally threaded; (b) a bezel which attaches to the body by projections which extend along the outside of the head portion and which have formations which snap engage with formations on the head portion to hold the bezel in position on the body; (c) a cup which fits onto the tail portion of the body and surrounds the head portion of the body and impedes movement of the projections which would otherwise permit the formations to disengage; and (d) a nut which fits onto the threaded tail portion of the body to hold the cup in place.

18. The switch of claim 17, wherein the head has a sidewall or sidewalls formed with longitudinally directed channels into which the projections of the bezel fit.

19. The switch of claim 18, wherein the projections fit into the channels so as not to protrude outwardly from the sidewall or sidewalls of the head.

20. The switch of claim 17, 18 or claim 19, wherein the bezel has at least three projections.

21. The switch of claim 17, 18 or 19, wherein the bezel has four projections.

22. The switch of any of claims 17-21, wherein the head is circular in outline.

23. The switch of any of claims 17-21, wherein the head is square or rectangular in outline.

24. The switch of any of claims 17-21, wherein the head is triangular in outline.

25. The switch of any of claims 17 to 24, wherein the bezel has an aperture which gives access to the plunger, and the plunger is dimensioned so that it cannot pass through the aperture.

26. The switch of any of claims 17 to 25, wherein the dimensions of the head and of a portion of the plunger that fits within the head are such that the greater part of their length is behind the bezel.

27. The switch of any of claims 17 to 26, formed as a body unit and a lamp and switch unit, which fit demountably together.

28. The switch of claim 27, wherein the body unit and the lamp and switch unit fit together by bayonet formations.

29. The switch of claim 27 or 28, arranged so that light from a lamp of the lamp and switch unit is visible through the plunger.