GB2098804A

GB2098804A - Electrical switch device

Info

Publication number: GB2098804A
Application number: GB8214334A
Authority: GB
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1981-05-15
Filing date: 1982-05-17
Publication date: 1982-11-24

Abstract

The electrical switch device (10) is for attachment to a printed circuit board (12) eg in a telephone, to enable a circuit therein to be made or broken. The device has a cup-shaped body (16) on which a carrier (18) is mounted for rotation relative thereto. The body (16) has hooked legs (24) which are snap- fitted into holes (26) in the board (12). An electrical connector element (20) fixed to the carrier (18) is resiliently urged into engagement with that surface of the board (12) carrying the conductor pattern so that by rotation of the carrier (18), an electrical circuit in the board (12) can be made or broken by the element (20). The carrier (18) can be rotated by engaging a screwdriver with a slot (42) in the carrier via an aperture (48) in the base (14) of the telephone. <IMAGE>

Description

SPECIFICATION Electrical switch device This invention relates to an electrical switch device, and is particularly intended for use in conjunction with a printed circuit board or like board upon which one or more electrical circuits are provided (hereinafter such a board will be referred to simply as "a circuit board").

Printed circuit boards at present used in telephones are currently provided with a number of predetermined circuits which are all wired up by means of upstanding pins which are electrically connected to various points on the circuit board. When the telephone is put into service, depending upon the function of the telephone, only a selected number of the circuits are required. Thus, it is necessary to remove wire links from those circuits which are not required. Currently, this removal operation is carried out by a telephone engineer who has to remove the base of the telephone and then remove the appropriate wire links which consist of short lengths of wire which have a socket on each end to connect with the upstanding pins.

Such an operation is obviously fairly laborious and means that, if once the links have been taken out in a particular telephone, it is not possible subsequently to bring the circuits into operation which have previously been taken out of operation, without removing at least the base of the telephone to do so.

It is an object of the present invention to provide an electrical switch device whereby the above mentioned disadvantages can be obviated or mitigated.

According to one aspect of the present invention, there is provided an electrical switch device comprising a body, a carrier mounted in or on the body for movement relative thereto, and an electric connector element mounted on the carrier, wherein the body is adapted to be mounted on a circuit board so that the electrical connector element is urged against the board, whereby, upon movement of the carrier relative to the body, at least one circuit on the board can be selectively made or broken or otherwise controlled by the connector element.

With such an arrangement, it is possible to provide printed circuit boards with any number of electrical switch devices according to the present invention and, upon installation of the printed circuit board in an electrical apparatus, for example a telephone, or upon installation of the apparatus itself, the appropriate circuit or circuits can be selectively made, broken or otherwise controlled by suitable movement of the carriers of the electrical switch devices.

In a preferred embodiment, the electrical connector element includes a pair of contact portions which are urged against the board when the body is mounted thereon.

Conveniently, the body is formed with support legs which are arranged to be snapengaged with the board, for example through apertures in the board.

In a particularly convenient embodiment, the electrical connector element is resilient and the body is formed with legs having hooked ends which are snap-fitted, in use, into holes in the circuit board so that the hooked ends engage with the opposite surface of the board to that against which the connector element engages, whereby the resilience of the connector element holds the hooked ends of the legs against the opposite surface of the board.

Conveniently, a portion of the carrier is exposed externally of the body and a formation is provided on or in said portion to enable a tool, such as a screwdriver, to be engaged therewith. With such a constructioii, it is envisaged that the apparatus fitted with a circuit board having one or more of the electrical switch devices thereon, could have a housing which is suitably apertured at the appropriate locations to enable access to be gained to said formation on each carrier without the need to remove the housing or a part thereof.

The body and the carrier may be so mutually arranged that they can be snap-engaged together whilst permitting rotation of the carrier relative to the body. Alternatively, the carrier may be provided with a flange which is disposed externally of the body, and a portion which extends through an aperture in a surface of the body and is engaged with the connector element, said connector element projecting laterally beyond the aperture so as to retain the carrier against disengagement from the body.

Conveniently, detent means are provided between the carrier and the body for releasably retaining the carrier in its set position relative to the body.

According to another aspect of the present invention, there is provided a combination of circuit board and at least one electrical switch device according to the present invention mounted on the circuit board so that the electrical connector element of the latter can be selectively moved to control at least one circuit on the board is completed.

According to a further aspect of the present invention, there is provided an apparatus, eg.

a telephone, having a housing and a combination of circuit board and at least one electrical switch device as defined in the last preceding paragraph mounted in the housing.

Most advantageously, the housing is provided with at least one aperture therein which is positioned so as to enable access to be gained to said at least one electrical switch device in order to move the carrier.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawing, in which Figure 1 is an axial section through one embodiment of electrical switch device according to the present invention fitted to a printed circuit board, Figure 2 is a plan view of the electrical switch device of Fig. 1, Figure 3 is an axial section through another embodiment of electrical switch device according to the present invention fitted to a printed circuit board, Figure 4 is a plan view of the electrical switch device of Fig. 3, Figure 5 is an underside plan view of a body forming part of an electrical switch device according to another embodiment of the present invention, Figure 6 is an axial section through the body of Fig. 5, Figure 7 is a side elevation of a carrier for use with the body of Figs. 5 and 6, Figure 8 is a side elevation of the carrier, perpendicular to the elevation of Fig. 7, Figure 9 is an underneath plan view of the carrier of Figs. 7 and 8, Figure 10 is an underneath plan view of a connector element for mounting on the carrier of Figs. 7 to 9, and Figure 11 is a side elevation of the connector element of Fig. 1 0.

Figure 12 is a view similar to Fig. 9 of a modified carrier, Figures 13 and 14 are views similar to Figs. 10 and 11, respectively, of a modified connector element, and Figure 15 is a view similar to Fig. 7 of the modified carrier of Fig. 1 2.

Referring now to Figs. 1 and 2, the electrical switch device is indicated by arrow 10 and is mounted on a printed circuit board 1 2 in a telephone having a base 14 forming part of a housing of the telephone. Only part of the base 14 is illustrated in Fig. 1.

The electrical switch device 10 comprises a cup-shaped synthetic resin body 1 6 which is of circular cross-section, a synthetic resin carrier 18 also of circular-cross section, and an electrical connector element 20. The body 1 6 is provided with a pair of diametrically opposed integral legs 22 having outwardly hooked ends 24 which are snap-fitted through respective holes 26 in the printed circuit board 1 2. The hooked ends 24 engage with an opposite side of the printed circuit board 1 2 to that on which the usual electrical conductor pattern is provided. The body 1 6 is also provided with a pair of integral, diametrically opposed location lugs 28 which are engaged in respective recesses (not shown) in the printed circuit board 1 2.

The carrier 1 8 includes a flange portion 30 which is disposed externally of the body 16, and a boss portion 32 of circular cross-section mounted for rotation in a circular aperture 34 in the body 1 6. At its end remote from the flange 30, the boss 32 is provided with a spigot 36 which has been passed through a non-circular aperture 38 in the connector element 20 and spread over in the manner of a rivet to engage the connector element 20 whereby the carrier 1 8 and the connector element 20 are retained together and in engagement with the body 1 6 but are rotatable relative to the latter.On its surface which is presented towards the body 16, the flange portion 30 is provided with four equi-angularly spaced recesses 39 (only one shown) which, together with a semi-spherical pip 40 on the body 1 6 define detent means between the carrier 1 8 and the body 1 6 to enable the carrier 1 8 to be releasably retained in a number of rotary positions relative to the body 16.

In an outer surface of the flange portion 30, ie in a surface which faces away from the body 16, the flange portion 30 is provided with a rectangular slot 42.

The connector element 20 basically comprises an annulus 44 stamped from a tinplated phosphor bronze sheet, the annulus 44 having a pair of peripherally extending arcuate portions 46 which are inclined so as to extend in the same direction out of the general plane of the annulus 44. These arcuate portions 46 define contacts which, when the electrical switch device 10 is mounted on the contact board 12, engage with a surface of the latter upon which a conductor pattern (not shown) is provided.Because of its shape and because of its material of construction, the connector element 20 not only acts as a bridging contact but also acts as a spring which retains the hooked ends 24 of the legs 22 in engagement with said opposite side of the printed circuit board 1 2 and also acts as a spring for permitting the necessary limited amount of axial movement of the carrier 1 8 relative to the body 1 6 which is necessary to enable engagement and disengagement of the recesses 39 with the pip 40 during rotation of the carrier 1 8.

It is to be appreciated that the conductor pattern on the printed circuit board 1 2 includes areas (not shown) which are to be connected together if a circuit in the circuit board 1 2 is to be completed. Such areas are engaged by the contact portions 46 in two of the four predetermined rotary positions of the carrier 1 8 which are set by the recesses 39 and the pip 40. In the other two of the four set positions, the contact portions 46 are not engaged with the contact areas and so the electrical circuit is not completed. Thus, the electrical circuit can be either made or broken simply by rotating the carrier 1 8 to the required angular position, this can easily be effected by means of a tool such as a screwdriver which is engaged in the slot 42.The base 14 of the telephone is provided with an aperture 48 therethrough to enable access to be gained to the slot 42 without removal of the base 14.

Thus, the required electrical circuitry on the printed circuit board 1 2 can be made or broken as required by the telephone engineer without the need to remove the base of the telephone and without the need to remove any wire links. Of course, if the intended use of the telephone is changed, previously open circuits can be closed simply by rotation of the appropriate carrier without the need to solder a new wire link in place. Additionally, assembly of the circuit board is facilitated because of the ease with which the electrical switch device can be snap-engaged therewith.

Referring now to the embodiment of Figs. 3 and 4, the electrical switch device illustrated therein is similar to that of Figs. 1 and 2 and similar parts are accorded the same reference numbers but prefixed by the numeral 1. In this embodiment, carrier 11 8 is engaged with body 1 16 in a snap-fit manner in view of the provision of boss portion 1 32 as a split part with outwardly directed hooked ends 1 50 engagable in a recess 1 52 surrounding circular opening 134 in the body 116. Flange portion 1 30 of the carrier 11 8 is disposed internally of the body 1 16 and is provided with a pair of integral posts 1 54 which pass through respective apertures in annular portion 144 of connector element 1 20.Pip 140 (see Fig. 4) is provided internally of the body 11 6 and is engagable in recesses 1 39 (only one shown) in that surface of the flange portion 1 30 which faces the inner surface of the body 116. Slot 142 for engagement by a tool such as a screwdriver is provided in an extension piece 1 56 which projects integrally from the flange 1 30 on the opposite side thereof to the boss 1 32. The extension piece 1 56 is of circular cross-section and passes with clearance through a circular hole 1 58 in the printed circuit board 1 2.

The electrical switch device of Figs. 3 and 4 operates in a similar way to that described with reference to Figs. 1 and 2.

Referring now to Figs. 5 to 11 of the drawings, the electrical switch device comprises a cup-shaped synthetic resin body 21 6 (Figs. 5 and 6), carrier 218 (Figs. 7 to 9), and connector element 220 (Figs. 10 and 11).

Parts of the electrical device of Figs. 5 to 11 which are similar to those of Figs. 3 and 4 are accorded the same reference numeral but in the 200 series rather than in the 100 series.

The body 21 6 is provided internally with a hexagonal recess 260 whose corners 239 define recesses for detent purposes. Formed on the lower surface of the base of the body 21 6 are first and second arcuate recesses 261 and 262, respectively. These recesses 261 and 262 have their generation centres coaxial with the axis of circular aperture 234.

Recess 261 subtends an angle of 120 degrees whilst recess 262 subtends an angle of 60 degrees. Carrier 218 can be mounted in either one of two positions in the body 216.

In one position, an integral lug 263 on flange 230 engages in recess 261 and, in the other position, the lug 263 engages in recess 262.

Thus, in the first position, the carrier 218 is movable through an angle of about 1 20 degrees relative to the body 216 whilst, in the other position, it is movable through an angle of about 60 degrees. In both cases, further angular movement of the carrier 218 relative to the body 216 is prevented because of engagement of the lug 263 with the appropriate end of the recess 261 or 262.

Flange portion 230 of carrier 218 is provided with large cut-outs 264 therein to define arcuate arms 265 on diametrically opposed portions on the circumference of the flange portion 230. Each arcuate portion 265 carries a respective integral pip 240. The dimension d (see Fig. 9) of the flange portion 230 in the region of the pips 240 is greater than the distance between the flats of the hexagonal recess 260 but less than the corner to corner dimension thereof. The arcuate portions 265 can be deformed inwardly because of the provision of the cut-outs 264. Thus, there is provided a detent mechanism defined by the recesses 239 and the pips 240.It will be manifest, therefore, that with suitable relative positioning between the recesses 261 and 262, the recesses 239, and the pips 240, two detent positions can be provided for the carrier 218 when the lug 263 is engaged in recess 262, whilst three detent positions are provided when the lug 263 is engaged in recess 261. Extension piece 256 is of noncircular section. Connector element 220 has a central aperture 267 of a corresponding shape and is an interference fit on the extension piece 256. In this embodiment, connector element 220 is formed from a sheet of phosphor bronze so as to be of circular outline.

Portions 268 of the element 220 are bent in the same direction out of the general plane of the sheet and are provided with spherical contact pips 270 formed by displacing a localised portion of the sheet. The above described electrical switch device is mounted on a printed circuit board in the manner described with reference to the embodiment of Figs. 3 and 4.

Referring now to Figs. 1 2 to 15, parts similar to those of Figs. 7 to 11 are accorded the same reference numerals but in the 300 series rather than the 200 series. Extension piece 356 of carrier 31 8 is of circular section rather than non-circular section and is provided with diametrically opposed, outwardly projecting ribs 372 thereon. Connector element 320 is arcuately curved with contact pips 370 disposed on the inside of the curve.

Central aperture 367 is of circular form with a pair of diametrically opposed, radially extending cut-outs 374. When the element 320 is mounted on the carrier 318, the ribs 372 engage in the respective cut-outs 374 to prevent relative rotation between the element 320 and the carrier 318. The opposite axial end portion 376 of the carrier 318 to extension 356 is not provided with hooked ends similar to hooked ends 250 illustrated in Fig.

7. Instead, said opposite axial end portion 376 is cylindrical with the same diameter as that of the extension piece 356 and is slotted at 378 in a like manner to slot 342. The outer periphery of the end portion 376 is provided with projecting pips 380 thereon which are spaced from flange portion 330 by a distance which is just greater than the axial length of circular aperture 234 (see Fig. 6).

The diameter of end portion 376 and the height of the pips 380 compared with the diameter of the aperture 234 are such that the end portion 376 can be pushed into the aperture 234 until the pips 380 have passed completely through the latter and then serve to hold the carrier 318 against disengagement from the body 216 in a similar manner to the hooked ends 250. The slot 378 provides an alternative location at which a screwdriver can be engaged with the carrier 31 8 to rotate the latter.

Instead of enabling at least one circuit on the board to be simply made or broken, any of the above-described switches may be arranged to control a component such as a variable resistor. In such a case, the connector element forms the movable contact of the variable resistor. The variable resistor may be of the type wherein the movable contact merely enables the resistance to be varied or it may be of the type including an on-off switch wherein movable contact is movable to a position in which it causes the variable resistor to be taken out of circuit.

Claims

1. An electrical switch device comprising a body, a carrier mounted in or on the body for movement relative thereto, and an electric connector element mounted on the carrier, wherein the body is adapted to be mounted on a circuit board so that the electrical connector element is urged against the board, whereby, upon movement of the carrier relative to the body, at least one circuit on the board can be controlled by the connector element.

2. An electrical switch as claimed in claim 1, wherein the body is hollow and has an opening therein in which the connector element is exposed.

3. An electrical switch as claimed in claim 1 or 2, wherein the electrical connector element includes a pair of contact portions which are urged against the board when the body is mounted thereon.

4. An electrical switch as claimed in claim 1, 2, or 3, wherein the body is formed with support legs which are arranged to be snapengaged with the board.

5. An electrical switch as claimed in claim 1, 2 or 3, wherein the electrical connector element is resilient and the body is formed with legs having hooked ends which are snapfitted, in use, into holes in the circuit board so that the hooked ends engage with the opposite surface of the board to that against which the connector element engages, whereby the resilience of the connector element holds the hooked ends of the legs against the opposite surface of the board.

6. An electrical switch as claimed in any preceding claim, wherein a portion of the carrier is exposed externally of the body and a formation is provided on or in said portion to enable a tool to be engaged therewith.

7. An electrical switch as claimed in any preceding claim, wherein the body and the carrier are so mutually arranged that they can be snap-engaged together whilst permitting rotation of the carrier relative to the body.

8. An electrical switch as claimed in any one of claims 1 to 6, wherein the carrier is provided with a flange which is disposed externally of the body, and a portion which extends through an aperture in a surface of the body and is engaged with the connector element, said connector element projecting laterally beyond the aperture so as to retain the carrier against disengagement from the body.

9. An electrical switch as claimed in any preceding claim, wherein detent means are provided between the carrier and the body for releasably retaining the carrier in a set position relative to the body.

10. An electrical switch as claimed in claim 9, wherein the detent means comprises at least one recess in the body and at least one projection disposed on a resilient portion of the carrier.

11. An electrical switch as claimed in claim 10, wherein the or each resilient portion comprises an arm defined by a cut-out in the carrier.

1 2. An electrical switch as claimed in any preceding claim, wherein the carrier is rotatable relative to the body and means are provided for limiting such rotation.

1 3. An electrical switch as claimed in any preceding claim, wherein the connector element is of generally concave form with the concavity facing outwardly of the body so as to face the circuit board when fitted thereto.

1 4. An electrical switch substantially as hereinbefore described with reference to Figs.

1 and 2, or Figs. 3 and 4, or Figs. 5 to 11 or Figs. 1 2 to 14 of the accompanying drawings.

1 5. A combination of circuit board and at least one electrical switch device as claimed in any preceding claim mounted on the circuit board so that the electrical connector element of the latter can be selectively moved to control at least one circuit on the board is completed.

1 6. An apparatus having a housing and a combination of circuit board and at least one electrical switch device as claimed in claim 1 5 mounted in the housing.

1 7. An apparatus as claimed in claim 16, wherein the housing is provided with at least one aperture therein which is positioned so as to enable access to be gained to said at least one electrical switch device in order to move the carrier.