IE51163B1 - Electrical switch with several selectors - Google Patents

Description

This invention relates to an electrical switch, and particularly to an electrical switch suitable for use as a coding device by providing a coded output signal from steady voltages applied thereto.

There is a need in many electrical installations for a coding device which functions to render the installation responsive to only a particular individual input signal.

An example of such an installation is an automatic garage door opening installation operated by signals transmitted by an authorised person.

A switch for such use should be of cheap and simple construction, and should be capable of being set simply to give a required coded output.

In Patent Specification FR - A-2,275,868 there is 15 described an electrical switch comprising a body of electrically insulating material carrying contacts which can be interconnected by means of a plurality of selector members movable relative to the body, there being a plurality of bus contacts and a plurality of individual contacts, the selector members being respectively associated with the individual contacts and each being operable selectively to connect the associated individual contact with any one of the bus contacts.

In this known switch each individual contact is of - 3 undulating form thereby to determine the necessary positions of the associated selector member relative to the bus contacts, and each selector member includes a contact having a pair of resilient arms one of which rides over the undulations in the associated contact while the other contacts the bus contacts as necessary.

This known switch suffers from the disadvantages that the individual contacts are of relatively complex form, this making production relatively difficult and expensive, and that the contact force provided by the contact of each selector member on the associated individual contact and the bus contacts derives solely from the resilience of a resilient contact arm and is thus relatively low and may even by broken by chattering of the resilient contact arm caused by vibration of the switch.

The present invention provides an electrical switch comprising a body of electrically insulating material carrying contacts which can be interconnected by means of a plurality of selector members movable relative to the body, there being a plurality of bus contacts and a plurality of individual contacts, the selector members being respectively associated with the individual contacts and each being operable selectively to connect the associated individual contact with any one of the bus - 4 contacts, wherein each selector member comprises a housing of electrically insulating material carrying a substantially C-shaped resilient contact having its free ends within the housing and formed on its bight with two projections arranged one to contact the associated individual contact at all times and the other to contact either a first or a second or no bus contact, the selector members being held in the required positions over the respectively associated individual contact by a cover secured over the body and having a plurality of slots in one face through each of which an operating member of a respective selector member housing projects, the free ends of the contact of each selector member engaging a projection in the associated housing thereby to maintain the contact in resilient engagement with the body and the associated individual contact and bus contacts carried thereby, and each side wall of each selector member housing being formed with a projection which engages in a row of three recesses formed in the adjacent wall of a cavity in the cover receiving the selector member thereby to determine the three necessary positions of the selector member relative to the cover and thus to the body.

The switch of this invention has the advantages that all the individual and bus contacts can be of single - 5 strip form, and that due to the form of the contact of each selector member and the manner in which the contact is held against the associated individual and bus contacts, reliable high force contact is provided at all times.

An electrical switch according to this invention will now be described by way of example with reference to the drawings, in which:Figure 1 Ib an exploded perspective view of parts of the switch; Figure 2 is a plan view of part of the switch; Figure 3 is a transverse sectional view through the switch of Figure 1 in the assembled state; Figure 4 is a sectional view on the line IV-IV in Figure 3; and Figure 5 is a sectional view on the line V-V in Figure 3.

The switch shown in the drawing comprises an elongate substantially rectangulold body 1 moulded from electrically insulating plastics material, and carrying first and second axially extending bus contacts 2 and 3, and a plurality of individual contacts 4. The first bus contact 2 extends along one longitudinal edge of the body 1, the individual contacts 4 are arranged in a row in spaced relationship along the other longitudinal edge of of the body 1, and the second bus contact 3 extends parallel to the first bus contact 2 and between the first bus contact 2 and the rov; of individual contacts 4. The body 1 has been moulded about the contacts 2, 3 and 4 such that the contact surfaces of the contacts 2, 3 and 4 are flush with a major surface of the body 1, as shown in Figure 3. Each of the contacts 2, 3 and 4 has a depending leg 5 for receipt in a hole in a substrate (not shown) all the legs 5 extending in the same direction from the body 1.

The body 1 is also formed with a plurality of transverse ribs 6 extending across the body 1 between adjacent individual contacts 4 and over the bus contacts 2 and 3, as clearly shown in Figure 2, there being a rib 6 at each end of the body 1. 33 Associated with each individual contact 4 is a respective selector member 7 comprising a housing 8 moulded from electrically insulating plastics material, and carrying a substantially C-shaped resilient metal contact 9 having its free ends 10 within the housing 8 (see Figure 3) and being formed on its substantially straight bight with two projections 11 arranged to contact the individual and bus contacts 2, 3 and 4 as will be described below.

The switch is completed by a cover 12 adapted to engage over the body 1 and be secured thereto, and having a plurality of slots 13 in one face through each - 7 51163 of which an operating member 14 of a respective selector member housing 8 projects for manual actuation, the cover 12 serving to hold the selector members 7 in the required positions over the respectively associated individual contacts 4.

As shown in Figure 3 the free ends 10 of the contact 9 engage a projection 15 in the associated housing 8 thereby to maintain the contact 9 in resilient engagement with the body 1 and the contacts 2, 3 and 4 carried thereby.

Each side wall of each selector member housing 8 is formed with a rounded projection 16 which engages in a row of three recesses 17 formed in the adjacent wall of a cavity 18 in the cover 12 receiving the selector member 7, thereby to determine three positions of the selector member 7 relative to the cover 12 and thus to the body 1.

As clearly shown in Figure 3, the length of each individual contact 4 and the positioning and width of the bus contacts 2 and 3 is such that with the selector member 7 in one end position (shown in Figure 3) relative to the cover 12 and body 1, the projections 11 on the contact 9 engage the individual contact 4 and the bus contact 2 respectively; in the middle position of the selector member 7 the projections 11 engage the individual contact 4 and the insulating surface of the body 1 between the bus - 8 contacts 2 and 3; and in the other end position of the selector member 7 the projections 11 engage the individual contact 4 and the other bus contact 3.

Thus, the complete switch can be used to provide 5 a coded output at the individual contacts 4 from two different voltages applied to the bus contacts 2 and 3, each individual contact 4 providing the voltage from either the bus contact 2 or the bus contact 3 (selector member 7 in either end position) or zero volts (selector member 7 in middle position). The switch shown in the drawings has nine selector members 7 and thus can provide any one of three to the power nine possible coded output signals from two voltages applied to the bus contacts 2 and 3 respectively.

Claims (2)

1. An electrical switch comprising a body of electrically insulating material carrying contacts which can be interconnected by means of a plurality of selector 5 members movable relative to the body, there being a plurality of bus contacts and a plurality of individual contacts, the selector members being respectively associated with the individual contacts and each being operable selectively to connect the associated individual 10 contact with any one of the bus contacts, wherein each selector member comprises a housing of electrically insulating material carrying a substantially C-shaped resilient contact having its free ends within the housing and formed on its bight with two projections arranged one 15 to contact the associated individual contact at all times and the other to contact either a first or a second or no bus contact, the selector members being held in the required positions over the respectively associated individual contacts by a cover secured over the body and 20 having a plurality of slots in one face through each of which an operating member of a respective selector member housing projects, the free ends of the contact of each selector member engaging a projection in the associated housing thereby to maintain the contact in resilient 25 engagement with the body and the associated individual - 10 contact and bus contacts carried thereby, and each side wall of each selector member housing being formed with a projection which engages in a row of three recesses formed in the adjacent wall of a cavity in the cover 5 receiving the selector member thereby to determine the three necessary positions of the selector member relative to the cover and thus to the body.

2. An electrical switch substantially as described with reference to and as shown in the accompanying drawings