Patent GB-1476630-A (GB)
Title: Multi-way electric switches
IPC: H01H19/56
Filed: 1974-09-13
Abstract: 1476630 Mechanical switches DEFENCE SECRETARY OF STATE FOR 13 Sept 1974 [14 Sept 1973 8 July 1974] 43377/73 and 30250/74 Heading H1N A multi-way commutator switch, i.e., a switch in which one-to-one connections between three or more inputs to an equal number of outputs can be changed according to a predetermined set of cyclic permutations by operation of the switch, includes two relatively movable members, wherein the first bears a first set of equispaced contacts, a second set of equispaced contacts, and a plurality of separate electrical interconnections each connecting one contact of the first set to one contact of the second set and disposed so that every pair of consecutive contacts in the first set is connected to a pair of contacts in the second set which are separated by a given number of spacings thereon, the separation being the same for every such pair; and wherein the second member bears a third set of contacts and a fourth set of contacts disposed so that they make simultaneous separate electrical connections to the contacts of the first set and the second set respectively when the members are suitably positioned relative to each other. As shown in Fig. 1, for example, the first contacts C1 to C7 on annular member M10 are connected to respective second contacts D1 to D7 separated by two spacings. The third and fourth sets of contacts B1 to B7 and E1 to E7 are carried on another member (not shown) and relative rotation of member M10 causes the connections from the third set of contacts to progress steadily around the fourth set; B1, for example, will be connected successively to E2, E3, E4 ... as M10 is stepped anti-clockwise from the position shown. The member carrying contacts C and D may be a disc (Fig. 2, not shown) wherein the interconnections are made without any cross-overs, or a drum (Fig. 3, not shown) with contacts C and D axially displaced, or by strapping in extra contacts (B1<SP>1</SP> to B7<SP>1</SP> and E1<SP>1</SP> to E7<SP>1</SP>, Fig. 4, not shown) a rectilinearly movable member (M13) may be utilized. In a second form of the invention the co-operating first and third set of contacts may be arranged to lie alternately on two tracks as T2 and T3 in Fig. 13, for example, wherein eight inputs and outputs require sixteen contacts in the third set B1 to B16. The eight contacts C5 to C12 of the first set need not be provided in practice; or contacts C1 to C16 may be strapped in pairs and half the brushes B1 to B16 omitted. A third form of the invention has the first and second sets of contacts interleaved and when mounted in a circular track their electrical interconnections may be geometrically parallel (Figs. 9 and 10, not shown). A switch with multiple slip-ring action may be provided by adding a fifth set of contacts (carried by the second member) and a co-operating sixth set of contacts (carried by the first member), consecutive contacts of the fourth set being connected to contacts of the fifth set which are consistently separated by an integral number of spacings. This maintains the electrical connections from fixed input contacts to respective movable output contacts effectively unchanged as the first and second members are moved relative to one another and may be applied to any of the three forms above, as exemplified, respectively, in Fig. 11 (not shown), Fig. 13 (contacts A1 to A8 added to second member S20, and contacts I1 to I8 added on part M20b which (with part M20a) forms the first member), and Fig. 12 (not shown). Switchable networks using the switch with multiple slip-ring action are provided by the addition of a seventh set of contacts on the first member co-operating with an eighth set on the second member, with electrical networks connected between the sixth and seventh sets of contacts (Figs. 1 to 4 with Provisional Specification 1,476,630, not shown). A practical form of the basic switch is shown in Fig. 5 with Provisional Specification 1,476,630. Inputs 40 are connected to outputs 41 by means of a rotor 43 comprising a flexible printed circuit board which is urged into engagement with a rigid printed circuit board stator 42 by axial movement of a rigid pressure plate 44 faced with foam rubber, after rotation to a chosen angular position. A toothed member 45 provides accurate registration of contacts by engagement in a circumferential rack member 46, and its tooth is skewed to give a slight rotation of the rotor during axial movement to ensure good electrical contact. Examples are given of the use of the various forms of the switch in direction finding systems to provide a sweeping lobe from a stationary circular array of aerials or receivers.