Means to prevent machine operation upon depression of plural keys

Claim 1

A KEY OPERATED MACHINE COMPRISING, IN COMBINATION: A PLURALITY OF KEYLEVERS; AN INTERPOSER ASSOCIATED WITH EACH OF SAID KEYLEVERS; A GROUP OF CODE TAPES; AND CORRESPONDING CHECK TAPES MOVABLE LONGITUDINALLY BETWEEN INOPERATIVE AND OPERATIVE POSITIONS; OPENINGS IN SAID CODE TAPES AND SAID CHECK TAPES IN ALIGNMENT WITH EACH OTHER AT POINTS OPPOSITE SAID INTERPOSERS WHEN SAID TAPES ARE IN THEIR INOPERATIVE POSITIONS, SAID OPENINGS ADAPTED TO RECEIVE SAID INTERPOSERS AND BEING OF SUCH LENGTH THAT EACH OF SAID TAPES IS EITHER HELD BY AN INTERPOSER AGAINST MOVEMENT OR IS PERMITTED TO MOVE TO ITS OPERATIVE POSITION, THE LENGTHS OF THE OPENINGS IN SAID CHECK TAPES BEING COMPLEMENTS OF THE OPENINGS IN THE CORRESPONDING CODE TAPES; MEANS YIELDING URGING SAID TAPES TOWARD THEIR OPERATIVE POSITIONS; MEANS RELEASABLY HOLDING SAID TAPES IN THEIR INOPERATIVE POSITIONS;