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US 4,793,165 AGranted
Protective device for key-operated door locks
OwnerHenri Rochmaninventor
Life of this patent
Estimating the term…
Abstract
A protective device for key-operated door locks, comprises a housing mountable to the door over the keyhole of a lock mounted within the door; a guard plate movable to a blocking position to block access to the keyhole, or to an unblocking position to permit access to the keyhole; and a rotary knob rotatable to a plurality of positions and having markings thereon indicating its position. A transmission mechanism including a plurality of notched code discs is provided between the rotary knob and the guard plate for moving the guard plate from its locking position to its unlocking position when the code discs have been positioned to predetermined coded positions such that further rotation of the knob moves the guard plate from its blocking position to its unblocking position.
Claims16
A protective device for key-operated door locks, comprising:
- a housing mountable to the door over the keyhole of a lock mounted within the door;
- a guard plate movable to a blocking position to block access to said keyhole, or to an unblocking position to permit access to said keyhole;
- a rotary knob rotatable to a plurality of positions and having markings thereon indicating its position;
- a transmission mechanism between said rotary knob and said guard plate for moving said guard plate from its blocking position to its unblocking position;
- said transmission mechanism including at least a first and a second code disc coupleable to said rotary knob such that rotating the rotary knob in one direction positions said first code disc according to the end position of the knob, and then rotating the knob in the opposite direction positions the second code disc according to the end position of the knob;
- said code discs having notches which are aligned with each other when the discs are in their predetermined code positions;
- and coupling means comprising an interposer member coupled to said guard plate and having a drive pin receivable in said notches when aligned to couple to interposer member to the rotary knob so as to pivot the interposer member by the further rotation of the knob;
- said interposer including a second pin received within an opening in the guard plate to move said plate to its unblocking position when the interposer member is pivoted by said rotary knob.
5 more elements
A protective device for key-operated door locks, comprising:
- a housing mountable to the door over the keyhole of a lock mounted within the door;
- a guard plate movable to a blocking position to block access to said keyhole, or to an unblocking position to permit access to said keyhole;
- a rotary knob rotatable to a plurality of positions and having markings thereon indicating its position;
- and a transmission mechanism between said rotary knob and said guard plate for moving said guard plate from its blocking position to its unblocking position;
- said transmission mechanism including a plurality of code discs coupleable to said rotary knob such that rotating the rotary knob positions the code discs according to the end positions of the knob;
- said transmission mechanism further including an interposer member controlled by said code discs and having a drive pin effective to couple said rotary knob to said interposer to pivot same when the code discs have been positioned to predetermined coded positions, said interposer including a second pin received within an opening in the guard plate to move said guard plate to its unblocking position when the interposer member is pivoted by said rotary knob.
3 more elements
A protective device for key-operated door locks, comprising:
- a housing mountable to the door over the keyhole of a lock mounted within the door;
- a guard plate movable to a blocking position to block access to said keyhole, or to an unblocking position to permit access to said keyhole;
- a rotary knob rotatable to a plurality of positions and having markings thereon indicating its position;
- and a transmission mechanism between said rotary knob and said guard plate for moving said guard plate from its blocking position to its unblocking position;
- said transmission mechanism including at least a first and a second code disc coupleable to said rotary knob such that rotating the rotary knob in one direction positions said first code disc according to the end position of the knob, and then rotating the knob in the opposite direction positions the second code disc according to the end position of the knob;
- said transmission mechanism further including coupling means controlled by said code discs and effective to couple said guard plate to said rotary knob when the code discs have been positioned to predetermined coded positions such that further rotation of the knob moves said guard plate from its blocking position to its unblocking position;
- said housing including a front cover plate formed with an opening rotatably receiving said knob, and a rear cover plate carrying a spindle on which said code discs are rotatably mounted, said rear cover plate being removably attached to said front cover plate by fasteners to permit removal of said front cover plate and thereby to permit access to said code discs for changing the code thereof, said interposer member being formed with a slot at its lower end receiving said spindle, and being pivoted about said spindle when coupled to the rotary knob to move the guard plate to its unblocking position.
4 more elements
Dependencies are inferred from the claim text.