GB1292644A - Improvements in or relating to multi-contact data feeders - Google Patents

Abstract

1292644 Key-operated switches; plug-in units CHIELMETTI AG 4 Nov 1969 [7 Nov 1968] 54092/69 Headings H1N and H1R Plug-in switches for mounting in an array on circuit boards or cross-bar matrices comprise fixed contact pins 14, 15 Fig. 1 which may be plugged into the switch bases 13 or are mounted in the bases 13 (as shown) for plugging into the boards and are selectively engaged by spring contact blades 21 under the action of plugs 30 Fig. 3, having cam faces 36 associated with each blade 21 required to be actuated. The cam faces 36 may be broken away where not required and each plug 30 may carry a cover plate 32 with indicia to identify the preset arrangement of the cams 36. Projection 37 on each plug engages a corresponding recess in the switch casing 11 whereby each plug can only be inserted in one position. A single long pin 15 provides a common input to a conducting plate 22 to which the lower ends of four diodes 23 are soldered at 24, the upper ends being soldered as at 25 to the upper end 19 of the contact blades 21 associated with four output pins 14. In a modification the diodes may be replaced in the switch casing by simple connecting wires, the diodes being mounted on the circuit boards. All the switches in one array may be plugged through apertures in a plastic foil sheet (38), Fig. 2 (not shown), whereby a complete array may be removed as a whole for replacement by another preset array. In a modification in which the pins, as 14, 15, engage a pair of circuit boards (41, 43), Fig. 5 (not shown), mounted one above the other, the shorter pins 14(44) are soldered to the upper board (43) and are plugged into the switch body. The longer input pin 15 (42) is permanently attached to the notch body and soldered to the lower circuit board 41 so that only this pin has to be unsoldered to remove the switch,