Key changing lock for safe deposit boxes

Claim 2

A changeable combination key lock for safe deposit boxes and the like, comprising a lock case, a locking bolt movable between projected and retracted bolt positions, a plurality of pivoted guard key tumblers having gating recesses for accommodating retraction of said bolt, a plurality of pivoted segmented tumblers having body segments and gated segments releasibly coupled therewith at variable positions, said tumblers normally occupying positions barring retraction of the bolt from projected position, a first rotatable key plug for insertion of a guard key therein to aline the guard key tumblers for retraction of the bolt, a second rotatable key plug for insertion of a renter''s key therein engaging said segmented tumblers and adjusting them to aline their gating recesses for retraction of the bolt and including means for moving the bolt between said positions upon rotation thereof, said tumbler body segments having cam follower surfaces, and a cam rotatably supported in the lock case adjacent said cam follower surfaces to be rotated between couple and release positions by a combination change key inserted in said first key plug, the cam having cam surfaces engageable with said cam follower surfaces upon rotation of the cam for decoupling the body segments from their companion gated segments to free the body segments to assume new positions corresponding to a new renter''s key selectively positioned in said second key plug.

Claim 3

A changeable combination key lock for safe deposit boxes and the like, comprising a lock case, a locking bolt movable between projected and retracted bolt positions, a plurality of pivoted guard key tumblers having gating recesses for accommodating retraction of said bolt, a plurality of pivoted segmented tumblers having body segments and gated segments releasibly coupled therewith at variable positions, said tumblers normally occupying positions barring retraction of the bolt from projected position, a first rotatable key plug for insertion of a guard key therein to aline the guard key tumblers for retraction of the bolt, a second rotatable key plug for insertion of a renter''s kay therein engaging said segmented tumblers and adjusting them to aline their gating recesses for retraction of the bolt and including means for moving the bolt between said positions upon rotation thereof, and a cam to be rotated between couple and release positions by a combination change key inserted in said first key plug for decoupling the body segments from their companion gated segments to free the Body segments to assume new positions corresponding to a new renter''s key selectively positioned in said second key plug, said gated segments having copuling teeth, said tumbler body segments including teeth on a first end thereof releasibly intermeshed with the teeth of said gated segments and including integral extensions at the opposite end thereof defining cam follower surfaces and said cam having a cam surface thereon for concurrently engaging said cam follower surfaces of said body segments upon rotation of the cam and retracting said body segments from intermeshed relation with the gated segments by movement in a direction corresponding to bolt retracting movement.

Claim 4

A changeable combination key lock for safe deposit boxes and the like, comprising a lock case, a locking bolt movable between projected and retracted bolt positions, a plurality of pivoted guard key tumblers having gating recesses for accommodating retraction of said bolt, a plurality of pivoted segmented tumblers having body segments and gated segments releasibly coupled therewith at variable positions, said tumblers normally occupying positions barring retraction of the bolt from projected position, a first rotatable key plug for insertion of a guard key therein to aline the guard key tumblers for retraction of the bolt, a second rotatable key plug for insertion of a renter''s kay therein engaging said segmented tumblers and adjusting them to aline their gating recesses for retraction of the bolt and including means for moving the bolt between said positions upon rotation thereof, and a cam to be rotated between couple and release positions by a combination change key inserted in said first key plug for decoupling the body segments from their companion gated segments to free the Body segments to assume new positions corresponding to a new renter''s key selectively positioned in said second key plug, said gated segments having copuling teeth, said tumbler body segments including teeth on a first end thereof releasibly intermeshed with the teeth of said gated segments and including integral extensions at the opposite end thereof defining cam follower surfaces and said cam having a cam surface thereon for concurrently engaging said cam follower surfaces of said body segments upon rotation of the cam and retracting said body segments from intermeshed relation with the gated segments by movement in a direction corresponding to bolt retracting movement.

Claim 5

A changeable combination key lock as defined in claim 1, wherein said guard key tumblers and segmented tumblers are pivotally mounted on a common tumbler post, said body segments having elongated slots receiving said post and accommodating decoupling retracting movement of the body segments codirectional to retracting movement of the bolt, the body segments having curved follower surfaces remote from the gated segments forming said cam follower surfaces partially encircling the axis of rotation of said cam at diametrically opposite zones about said axis, and said cam having a surface moveable into contact with said follower surfaces to a first position for retracting said body segments to a decoupled position relative to their companion gated segments and to a second position for returning the body segments to coupled relation with the gated segments.

Claim 6

A changeable combination key lock as defined in claim 1, wherein said segmented tumblers are arranged in side-by-side stacked relation collectively defining a tumbler stack, said cam member having an arm transversely spanning the whole stack of tumblers eccentric to the axis of rotation of the cam to concurrently engage portions of said body segments upon rotation of the cam to decoupling and recoupling positions.

Claim 7

A changeable combination key lock as defined in claim 2, wherein said segmented tumblers are arranged in side-by-side stacked relation collectively defining a tumbler stack, said cam member having an arm defining said cam surface transversely spanning the whole stack of tumblers eccentric to the axis of rotation of the cam to concurrently engage the cam follow surfaces of said body segments upon rotation of the cam to decoupling and recoupling positions.

Claim 8

A changeable combination lock key as defined in claim 1, wherein said segmented tumblers are arranged in side-by-side stacked relation with said guard key tumblers interleaved in alternation between each successive pair of segmented tumblers collectively defining a tumbler stack, said cam member having an arm transversely spanning the whole stack of tumblers eccentric to the axis of rotation of the cam to concurrently engage portions of said body segments upon rotation of the cam to decoupling and recoupling positions.

Claim 9

A changeable combination key lock as defined in claim 2, wherein said segmented tumblers are arranged in side-by-side stacked relation with said guard key tumblers interleaved in alternation between each successive pair of segmented tumblers collectively defining a tumbler stack, said cam member having an arm defining said cam surface transversely spanning the whole stack of tumblers eccentric to the axis of rotation of the cam to concurrently engage the cam follow surfaces of said body segments upon rotation of the cam to decoupling and recoupling positions.

Claim 10

A changeable combination key lock as defined in claim 1, wherein said bolt and cam have confronting shoulder portions restraining said cam against movement from said couple position when said bolt occupies said projected position and freeing said cam for movement to its release position only when the bolt is retracted.

Claim 11

A changeable combination key lock as defined in claim 2, wherein said bolt and cam have confronting shoulder portions restraining said cam against movement from said couplE position when said bolt occupies said projected position and freeing said cam for movement to its release position only when the bolt is retracted.

Claim 12

A changeable combination key lock as defined in claim 1, wherein said bolt includes an elongated bolt plate portion spanning the major portion of said lock case and having an opening therein accommodating said cam, said cam having peripheral interruptions defining oppositely facing shoulders, and said bolt plate portion having stop formations substantially abutting said shoulders when the bolt occupies said projected position to prevent rotation of the cam from said couple position, said stop formations being displaced from adjacent the cam when the bolt reaches retracted position to free the cam for rotation to release position.

Claim 13

A changeable combination key lock as defined in claim 2, wherein said bolt includes an elongated bolt plate portion spanning the major portion of said lock case and having an opening therein accommodating said cam, said cam having peripheral interruptions defining oppositely facing shoulders, and said bolt plate portion having stop formations substantially abutting said shoulders when the bolt occupies said projected position to prevent rotation of the cam from said couple position, said stop formations being displaced from adjacent the cam when the bolt reaches retracted position to free the cam for rotation to release position.