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US 7,406,846 B2Granted
Electromechanical lock employing shape memory metal wire
AssigneeNanotechnology, Inc.
InventorJohn Wun-Sing Chu
Life of this patent
Estimating the term…
Abstract
An electronic lock incorporating one or more shape memory metal wire segment as its electromechanical transducer. An electronic control circuit injects electrical current into the shape memory metal wire, causing it to heat up and contract. A gate is positioned by the action of the shape memory metal wire(s) to either allow or block the movement of a locking bolt that affect locking or unlocking. Millions of operational cycles are achieved by limiting the stretching of the shape memory metal wire at low temperature to small percentages of its total length. The design lends itself to miniaturization, with commensurate reduction in power consumption, that is useful to the evolution of future electronic locks.
Claims16
An electronic lock comprising:
- a shell having a bore therein;
- a plug disposed in said bore of said shell;
- a groove in either said shell or said plug;
- a gate connected to said plug or said shell wherein when said gate enters said groove in a locked position, it limits movement of said plug relative to said shell;
- a mechanism biasing said gate into the locked position;
- a first shape memory metal wire segment with a transition temperature that moves said gate from the locked position to an unlocked position away from the groove in response to an electrical current therein;
- an electronic control circuit for injecting electrical current into said first shape memory metal wire segment to unlock the lock;
- a second shape memory metal wire segment with said transition temperature arranged to contract concurrently with opposite force to that caused by contraction of said first shape memory metal wire segment when ambient temperature rises above said transition temperature of said shape memory metal wires so that said gate is retained in the locked position by said mechanism.
5 more elements
An electronic lock comprising:
- a shell having a bore therein;
- a plug disposed in said bore of said shell;
- a groove in either said shell or said plug;
- a gating mechanism having a member connected to said plug or said shell,
- wherein when said member enters said groove in a locked position, it limits movement of said plug relative to said shell;
- a first device biasing said gating mechanism so that the member is in the locked position;
- at least one first shape memory metal wire segment with a transition temperature in non-elastic connection with said plug or said shell, said at least one first shape memory metal wire segment moving said gating mechanism or a component thereof from a first locking position to a second unlocking position in response to an electrical current in the at least one first shape memory metal wire segment and causing the member to be withdrawn from the locked position in the groove;
- and
- an electronic control circuit for injecting electrical current into said at least one first shape memory metal wire segment to unlock the lock;
- and
- said gating mechanism is connected to a second share memory metal wire segment that contracts concurrently with substantially equal but opposite force to that caused by contraction of said first shape memory metal wire segment when ambient temperature rises above said transition temperature of said shape memory metal wire segments so that said member is retained in the locked position by said first device.
8 more elements
An electronic lock comprising:
- a shell having a bore therein;
- a plug disposed in said bore of said shell;
- a groove in either said shell or said plug;
- a gating mechanism having a member connected to said plug or said shell,
- wherein when said member enters said groove in a locked position, it limits movement of said plug relative to said shell;
- a first device biasing said gating mechanism;
- at least one first shape memory metal wire segment with a transition temperature moving said gating mechanism, so that said member is moved from the locked position to an unlocked position in response to an electrical current in the at least one first shape memory metal wire segment;
- and
- an electronic control circuit for injecting electrical current into said at least one first shape memory metal wire segment to unlock the lock, wherein the at least one first shape memory metal wire segment is stretched by not more than 6% between the locked and the unlocked positions;
- and
- said gating mechanism is connected to a second shape memory metal wire segment that contracts concurrently with substantially equal but opposite force to that caused by contraction of said first share memory metal wire segment when ambient temperature rises above said transition temperature of said share memory metal wire segments so that said member is retained in the locked position by said first device.
8 more elements
A method of electronically locking and unlocking, comprising:
- (a) providing an electronic lock comprising:
- a shell having a bore therein;
- a plug disposed in said bore of said shell;
- a groove in either said shell or said plug;
- a gating mechanism having a member connected to said plug or said shell, wherein when said member enters said groove in a locked position, it limits movement of said plug relative to said shell;
- a first device biasing said gating mechanism;
- and
- at least one first shape memory metal wire segment with a transition temperature moving said gating mechanism, so that said member is moved from the locked position to an unlocked position in response to an electrical current in at least one first shape memory metal wire segment;
- and
- a second shape memory metal wire segment connected to said gating mechanism so that said second shape memory metal wire segment contracts concurrently with substantially equal but opposite force to that caused by contraction of said first shape memory metal wire segment when ambient temperature rises above said transition temperature of said shape memory metal wire segments so that said member is retained in the locked position by said first device;
- and
- (b) injecting electrical current into said at least one first shape memory metal wire segment to unlock the lock, wherein the at least one first shape memory metal wire segment is stretched by not more than 6% between the locked and unlocked positions.
9 more elements
A method of electronically locking and unlocking, comprising:
- (a) providing an electronic lock comprising:
- a shell having a bore therein;
- a plug disposed in said bore of said shell;
- a groove in either said shell or said plug;
- a gating mechanism having a member connected to said plug or said shell, wherein when said member enters said groove in a locked position, it limits movement of said plug relative to said shell;
- a first device biasing said gating mechanism;
- and
- at least one first shape memory metal wire segment with a transition temperature moving said gating mechanism from the locked position to an unlocked position in response to an electrical current in the at least one first shape memory metal wire segment;
- and
- a second shape memory metal wire segment connected to said gating mechanism so that said second shape memory metal wire segment contracts concurrently with substantially equal but opposite force to that caused by contraction of said first shape memory metal wire segment when ambient temperature rises above said transition temperature of said shape memory metal wire segments so that said gating mechanism is retained in the locked position by said first device;
- and
- (b) injecting electrical current into said at least one first shape memory metal wire segment to unlock the lock, wherein said providing includes connecting said at least one first shape memory metal wire segment non-elastically directly or indirectly with said plug or said shell.
9 more elements
Dependencies are inferred from the claim text.