Locks – Operating mechanism – Using a powered device
Reexamination Certificate
1999-04-16
2001-05-29
Boucher, Darnell (Department: 3627)
Locks
Operating mechanism
Using a powered device
C070S406000, C070S395000, C070S278200
Reexamination Certificate
active
06237379
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electromechanical lock system. More particularly this invention concerns such a system having a motor that offers a power assist to the operation of the key.
BACKGROUND OF THE INVENTION
A standard motor-assist door latch is described in U.S. Pat. No. 5,394,718 of Hotzl as having a main lock housing, a bolt movable in the housing between a locked position projecting from the housing and an unlocked position largely recessed in the housing, a key-operable mechanism having an actuator movable by turning of an appropriately bitted key in the mechanism, and a linkage between the actuator and the bolt for displacing the bolt by means of the actuator. A secondary housing is provided adjacent the lock housing and an actuator element coupled and movable with the linkage extends from the lock housing to the secondary housing. The element moves in one direction relative to the secondary housing on movement of the bolt from the locked to the unlocked position and in the opposite direction on movement of the bolt from the unlocked to the locked position. An electric motor on the secondary housing connected to the element is energizable for displacing same in both directions and thereby also displacing the bolt between its positions. Switches on the secondary housing juxtaposed with the element and connected to the motor detect movement of the element in either direction when actuated through the linkage by the key and energize the motor to move the element in the same direction it is already moving in. Thus the motor gives the key a sort of power assist.
Such an assembly is typically used to operate a high-security multibolt door lock which presses bolts in several directions into the jamb. Thus the motor is normally needed to move the considerable amount of equipment that must be displaced to lock and unlock the door. Even if all the various bolts and linkages are finely machined and oiled, they nonetheless constitute quite some mass that would make turning the key a serious chore and, therefore, would militate against use of the lock.
The obvious problem with this type of motor-assisted lock is that if the power fails the door is locked and cannot be opened. It becomes necessary to provide some sort of auxiliary unlocking mechanism that not only unnecessarily augments the cost of the lock, but presents a weak point at which the lock can be attacked for unauthorized entry.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved motor-assist electromechanical lock system.
Another object is the provision of such an improved motor-assist electromechanical lock system which overcomes the above-given disadvantages, that is which can be operated mechanically if the power for its motor fails.
SUMMARY OF THE INVENTION
A lock system has according to the invention a housing, a barrel rotatable in the housing about an axis from a center position, tumblers radially displaceable in the barrel and housing between an unlocked position permitting the barrel to rotate in the housing out of the center position and a locked position blocking rotation of the barrel in the housing and retaining the barrel in the center position, and an actuating element rotatable in the housing about the axis and juxtaposed with an inner end of the barrel. Lock members are operable by the element and a switch in the housing is operable by the barrel on displacement out of the center position to energize an electric motor that can rotate the element and thereby mechanically operate the lock members. According to the invention a key fittable in the barrel is displaceable axially therein through an axial stroke between an outer position and an inner position. The key is formed with bit surfaces extending axially through a distance equal at least to the stroke and is engageable with the tumblers to hold the tumblers in the unlocked position in both the inner and outer key positions. The key has a tip projecting in the inner key position into the actuating element and rotationally coupling the actuating element to the barrel and standing clear of the element in the key outer position and decoupling the element from the barrel so that in the inner position the key can turn the element directly while in the outer position the element can only be turned by the motor.
Thus with this system when the key is in the outer position it serves merely to rotate the barrel and operate the switch, thereby functioning like a standard motor-assisted lock. If the electrical power supply for the motor fails, however, the key can be pushed into the inner position in which it will physically connect with the actuating element that it otherwise normally only operated by the motor, so that this actuating element can itself be operated by the key. Thus the lock has, in affect, a mechanical override that in no way compromise its security and that adds little to the cost of the system.
The key according to the invention is provided with an abutment displaceable between a blocking position engageable with the barrel and inhibiting axial displacement of the key into the inner position and a freeing position permitting axial displacement of the key into the inner position. This abutment, which can be formed by an elastically deflectable plate fixed on the key, therefore normally inhibits movement into the inner position for normal operation of the latch. Only in an emergency is it deflected out of the way so the key can assume the inner position.
In another system in accordance with the invention the abutment is electromagnetically normally urged into the blocking position and only moves into the freeing position when an electric power source for itself and the motor fails. Thus when power fails the user does not need to take any special steps and will merely find that his or her key does farther into the lock, then rotates through a larger angle and is somewhat harder to turn, as it is directly operating the mechanical elements of the lock, but otherwise use of the lock will be identical as in motor-assist mode.
REFERENCES:
patent: 3942347 (1976-03-01), Coleman
patent: 5202580 (1993-04-01), Janssen
patent: 5404737 (1995-04-01), Hötzl
patent: 5469727 (1995-11-01), Spahn et al.
patent: 5628217 (1997-05-01), Herrera
patent: 5629505 (1997-05-01), Cryer
patent: 5691711 (1997-11-01), Jorgensen
patent: 5791177 (1998-08-01), Bianco
patent: 5839305 (1998-11-01), Aston
patent: 5946956 (1999-09-01), Hötzl
patent: 92 07 789 U (1992-10-01), None
patent: 93 03 702 U (1994-08-01), None
patent: 0 779 404 (1997-06-01), None
patent: 2 176 531 (1986-12-01), None
Boucher Darnell
Dubno Herbert
Roto Frank Eisenwarenfabrik AG
Wilford Andrew
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