ES352977A1 - Miniature crossbar multiswitch - Google Patents

Abstract

A cross-bar switch comprises a base-plate formed by a printed circuit board 1, Fig. 1, on which a number of resilient contact elements 5 are mounted, two rows only being shown, each contact element being anchored at one end to the board in electrical contact with a circuit on the board. The base is fixed to the lower surface of a frame 8 which accurately locates the lower ends of the contact elements and which carries on its upper surface the select and connect bars 12 and 13, only two of each being shown, which are movable by operation of the electromagnetic actuators 27 and 28. Mounted over the top of frame 8 is a contact support plate 38, the top surface of which is grooved, as at 41, to take stationary contact elements 40 in the form of springs, as described in Specification 1,100,875, which are held in place by ribs 44 on lid 39 which engage transverse grooves 98 in the support plate 38 and apply retaining pressure on the springs 40. The bottom surface of the support plate is grooved to provide an L-shaped guiding path for the free ends of the contact elements 5 between a position in which the elements 5 are out of contact with the fixed contact springs 40 and a position where they engage between adjacent turns of the spring. The select and connect bars are each resiliently biased in a direction away from the actuators 27 and 28 by spring- loaded tongue members in the walls 19 and 20 of the frame 8 and are displaced in the other direction when the actuators are energized. Each select bar 12 has a number of rectangular apertures through which respective movable contact elements pass and each connect bar has a number of rectangular apertures each having a tooth projecting into the interior thereof. Switch operation.-Normally, the movable contact elements, e.g. 57 and 58, Fig. 4, which shows only the active portions of the apertures in the select and connect bars, are biased by their own resilience into one corner of the bar apertures. To select a cross-point the connect bar is operated to the position shown in Fig. 5 then the select bar is operated as at 51 in Fig. 7, the connect bar is released, the tooth 56 carrying the movable contact to engage the fixed contact 59 and finally the select contact is released leaving the selected movable contact 58 still held, by the restoring spring action on the connect bar, in contact between adjacent turns of the fixed contact spring 59. To release the connection the connect bar is operated once again when the movable contact returns, by its own resilience, to its original position.