Mechanism for preventing simultaneous locking of multi-column switches

Claim 1

A mechanism for preventing simultaneous actuation of first and second switches in first and second columns, respectively, of a multicolumn switch assembly, the columns being arranged longitudinally and having a plurality of switches in each column, comprising: each switch having a slide portion which is depressable from a first position to a second position, said slide having on one side thereof a bearing surface; first and second slidable preventing members arranged longitudinally spaced apart in parallel with each other, each preventing member being disposed with respect to a respective one of said columns of switches and having a plurality of cutout portions each engageable with a bearing surface of a corresponding one of the switches in the respective column when the slide portion is depressed to the second position so as to slide the preventing member by a predetermined distance in one longitudinal direction of the assembly, said first and second preventing members being slidable in opposite longitudinal direction from the other when switches in the respective columns are depressed; said first and second preventing members having first and second bearing sections, respectively, which extend toward each other so as to be engageable with each other if said first and second preventing members are both moved at the same time in opposite longitudinal directions, said first and second bearing sections being initially spaced apart by a gap smaller than the sum of the predetermined distances the preventing members must move if switches in both columns are simultaneously depressed to the second position, whereby the bearing sections will compete for space in said gap so that only one of the two preventing members can slide the full length of its predetermined distance of longitudinal movement at a time.