MULTI-WAY SWITCH

Abstract: A microswitch assembly comprises a circuit board (1) having at least one microswitch element (e.g. 2) mounted on it, the or each microswitch element comprising a movable element (7) arranged for snap-action movement between a rest position and an operative position in which electrical contact is completed between respective portions of electrical circuits on the board (1). The assembly may comprise a joystick assembly having a control shaft extending through an aperture (18) in the circuit board, there being four switch elements (2, 3, 4, 5) mounted to the board (1) and arranged symmetrically around the aperture, so that the control shaft serves to actuate the switch elements selectively.

Description: Multi-wa Switch The present invention is concerned with multi-way switches and particularly, but not exclusively, switches comprising four coplanar switch elements, which are suitable for use with joysticks. Joystick assemblies conventionally comprise a housing and a joystick lever extending through the top of the housing. In one form of joystick assembly, four microswitches are arranged within the housing, in a common plane, symmetrically around the shaft of the joystick lever. The microswitches are arranged to be actuated by the joystick shaft in response to manual manipulation thereof, so that horizontal and/or vertical movement of a cursor on the VDU screen can be thereby controlled by movement of the joystick away from its neutral position (perpendicular to the common plane of the microswitches) . While such a joystick assembly is very satisfactory in operation, the use of four separate microswitches, each in its own casing and each with its own electrical connections, places considerable demands upon the use of space within the housing of the joystick assembly. It is an object of the invention to provide a multi-way switch suitable, in some embodiments, for use in such a joystick assembly as a replacement for the previously used four microswitches. According to the present invention, there is provided a microswitch comprising a circuit board having at least one microswitch element mounted thereon, the or each microswitch element comprising a movable member arranged for snap-action movement between a first operative position and a second operative position in which electrical contact is completed between respective portions of electrical circuit on the circuit board. Ihe switch elements (which are- generally four in number) are preferably arranged symmetrically around an aperture in the circuit board. The electrical connection completed by movement of each of the movable members is preferably a separate track on the circuit board; all these tracks preferably terminate at one edge of the board. The present invention further comprises a joystick assembly which comprises a housing having therein a multi-way switch element as described above with four switch elements arranged symmetrically around an aperture in the circuit board thereof, and a joystick having an elongate shaft passing through said aperture and extending beyond said housing, said shaft being movable from an equilibrium position in which it is contact with actuators for each of said switch elements and a series of eight operative positions encircling said equilibrium position in which operative positions either a single actuator or two adjacent actuators are actuated. The switch elements are preferably such that they resiliently bias the joystick shaft to the neutral position which is perpendicular to the plane of the circuit board. The switch elements are typically of an over-.centre snap-action pivot arm type. Preferably the or each switch element comprises a conductor member which the movable member contacts in its second, operative position and these members are individually mounted to the circuit board (i.e. separately and independently of each other) . Thus the components of the switch element are not required to be assembled into a switch housing which must then be mounted to the circuit board. A preferred embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawing, which is a partially exploded perspective view of an exemplary multi-way switch according to the invention (in which the switch elements are the snap-action type mentioned above) . Referring to the drawing, the switch comprises a board 1 having four mutually perpendicular switch elements 2, 3, 4, 5 mounted thereon. Switch element 2 will now be described in more detail but it should be understood that switch elements 3, 4, 5 are all generally similar. Switch element 2 comprises a pivot arm 6, a switch wiper arm 7, a terminal post 8, which is spaced from (and normally out of electrical contact with) , a pivot post 9, a terminal rest post 10, a spring 11 and a spring mounting post 12. These components of the switch element are as shown individually mounted to the circuit board, avoiding the need for assembly of these into a housing which is then mounted to the circuit board. When arm 6 is biassed in the direction of arrow A by an actuator (not shown) , it is caused to pivot about its end which is retained by pivot post 9; the resilient biassing action of the spring 11 urges switch wiper arm 7 away from rest post 10 towards terminal post 8, to make electrical contact between respective projections 7a and 8a on the wiper arm 7 and on the terminal post 8. On removal of the bias by the actuator, the switch wiper arm 7 is caused to return to its rest position, in which it is in contact with the rest post 10, by the action of the spring 11. Each of the terminal post 8 and pivot post 9 are mounted in the board 1 in electrical contact with a conductive pattern in the board ; the connections from each of the switch elements 2, 3, 4, 5 all terminate at one edge 13 of the board in a manner such that they can mate with an appropriate interface connection. Edge 13 is provided with a series of slots 14 to assist such mating. A housing comprising a base 15 and a cover 16 is also provided; the base 15 and cover 16 are arranged to be clamped together with the board 1 and associated switch elements 2, 3, 4, 5 therebetween in the required spatial relationship. ' Cover 16 has a central aperture 17; board 1 has an aperture 18 in a corresponding position (as does base 15, although the aperture in the base cannot be seen in the drawing). In use, a joystick shaft (not shown) passes through the three apertures mentioned; appropriate movement of the joystick shaft can cause actuation of the respective one of the switch elements 2, 3, 4, 5, or any two adjacent ones thereof (that is, 2 and 3, 3 and 4, 4 and 5 or 5 and 2).

Claims: CLAIMS : 1. A microswitch comprising a circuit board having at least one microswitch element mounted thereon, the or each said microswitch element comprising a movable member arranged for snap-action movement between a first operative position and a second operative position in which electrical contact is completed between respective portions of electrical circuit on said board, 2. A microswitch according to claim 1, in which the electrical connection completed by movement of the or each movable member is a separate track of the circuit board. 3. A microswitch according to claim 1 or 2, in which substantially all of the tracks on said board terminate at one edge thereof. 4. A microswitch according to any of claims 1 to 3, in which the or each switch element comprises a conductor member which said movable member contacts in its second, operative position, the movable member and conductor member being individually mounted to the circuit board. 5. A microswitch according to any of claims 1 to 4, in which a plurality of said switch elements are arranged symmetrically around an aperture in said circuit board. 6. A microswitch according to claim 5, in which the number of said switch elements arranged around said aperture is four. 7. A joystick assembly which comprises a housing having therein a microswitch according to claim 6 and a joystick having an elongate shaft passing through said aperture and extending beyond said housing, said shaft being movable from an equilibrium position in which it is in contact with actuators for each of said four switch elements and a series of eight operative positions encircling said equilibrium position in which operative positions either a single actuator or two adjacent actuators are actuated. δ. A joystick assembly according to claim 7, in which said switch elements are such that they resiliently bias the joystick shaft to said neutral position, in which position said shaft is substantially perpendicular to the plane of the circuit board.

Inventors: HOLLOWAY WYNFORD, HOLLOWAY, WYNFORD
Applicants: CREATIVE DEVICES RES LTD, CREATIVE DEVICES RESEARCH LIMITED
Application year: 1988
Main classification: H01H1
IPC codes: G05G9, H01H1, H01H25