Combination lock with self-canceling mechanism
AssigneeC L Industries, Inc.
InventorClaude Legault
Life of this patent
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Abstract
A combination door lock having a self-canceling combination mechanism which is secured inside the lock housing and is provided with spring-biased hook engaging fingers which engage one or more of the combination discs when these discs are aligned at a predetermined position where a retracting cam engages a bolt-retracting lever. Once the bolt is retracted by the lever these hook fingers engage with an associated combination disc and move it out of its predetermined position to a random position thereby scrambling or self-canceling the combination or the placement of the discs. Accordingly, it is not possible to predict the precise position of the combination discs after the bolt has been retracted and the door opened.
Claims12
In a combination door lock having a lock housing, a spring-biased bolt having a locking free end, said bolt being spring-biased for sliding movement so that said free end is normally biased extending out of said housing, a manually operable combination element outside said housing, said combination element displacing one or more combination discs rotatable upon a common axis, each said one or more discs having a notch formed in an outer periphery thereof, a bolt retracting cam displaceable about said common axis, a bolt retracting lever pivotally connected to said bolt, said retracting lever having a retracting cam engaging means and a support pin supported on the outer periphery of said discs, said bolt retracting cam having means to engage said retracting cam engaging means, said one or more combination discs when positioned at a predetermined position by said combination element causing said notch(es) to align and said support pin to enter said notch(es) of said one or more discs and causing said retracting cam engaging means to engage said bolt retracting cam whereby upon further rotation of said combination element said bolt will be retracted by said bolt retracting lever, the improvement comprising self-cancelling combination means secured inside said housing and having disc engaging means for engaging one or more of said one or more combination discs when said one or more combination discs are positioned at said predetermined position, said disc engaging means being a spring-biased hook finger engaging in said notch of its associated combination disc for displacing its associated engaged disc out of position when said support pin moves out of said notch of said one or more discs prior to full retraction of said bolt by said retracting cam.
Dependencies are inferred from the claim text.