Mechanism for preventing the simultaneous locking for use in a push button device

Claim 1

In a switch device including a plurality of push buttons movable inwardly to a latched state, a mechanism for preventing simultaneous latching of more than one push button, including a respective cam-engaging portion extending outwardly from each said push button, means including respective spring elements for each said push button urging said push buttons to the un-latched position, a common cam member located adjacent said push buttons and having a plurality of cam surfaces lying oppositely respective cam-engaging portions, means including at least one spring member urging said cam surfaces towards engagement with said cam-engaging portions to apply a force whereby inward movement of any push button towards its latched position can slide the cam-engaging portion associated therewith against the respective cam surface to move the cam member out of engagement with any previously latched push button and, after the cam-engaging portion has moved past the respective cam surface, urge said cam surface against the cam-engaging portion of the actuated push button with sufficient frictional resistance therebetween to hold the actuated push button in its latched position, said force being insufficient to hold two of said push buttons in their latched position against the resilient forces applied by the spring elements thereof.