Locks – Operating mechanism – Key
Reexamination Certificate
1998-07-27
2001-03-06
Barrett, Suzanne Dino (Department: 3627)
Locks
Operating mechanism
Key
C070S33300A, C070S278100, C070S30300A
Reexamination Certificate
active
06196037
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to locks, especially electronic locks having motor-driven bolts. More specifically, the invention relates to locks in which it is desired that the bolt, once extended, cannot be forcibly pushed in but can only be withdrawn into the lock with entry of a proper combination or other authorization. The invention also relates to locks in which it is desired to respond to certain types of physical attack by rendering the bolt incapable of being withdrawn. The invention further relates to locks in which various security enhancements are provided.
2. Related Art
Numerous conventional lock designs have been provided in which a bolt may be extended or withdrawn in response to entry of a combination of other authorization. However, some of the designs have not provided a “dead bolt” feature, which involves physical blocking of the extended bolt so that, after the bolt has been extended into its “locked” position, the lock resists externally applied pressure that attempts to force the bolt back into the lock case.
Also, it is envisioned that locks are physically attacked in may ways, including drilling into the lock case. It is desired that a lock not merely physically resist such attacks, but also respond appropriately to such attacks by ensuring that the bolt cannot be withdrawn during or after the attack. In other words, it is desirable to prolong or perpetuate the “dead bolt” state so that in the event of physical attack, it becomes even harder for a perpetrator to gain entry into the protected area. Many known locks do not prolong or perpetuate a “dead bolt” state after the lock has been physically attacked, and thus do not provide adequate additional protection in that scenario.
Further, many known lock systems that involve “bolt works” require two separate actions to extend the blocking member from the door into the doorjamb, and to re-extend the bolt from the lock case. This is not merely inconvenient, but presents an additional security risk should the individual neglect to perform the second action. Additionally, it is desirable in such systems to provide a “bolt throw” (extent of movement of the bolt) that is adjustable so as to easily adapt a single lock to a variety of installations and different types of bolt works.
Moreover, many known lock systems possess minimal locking functions, and do not provide additional security enhancement features. Applicants have recognized that such security enhancements include detection and response to tampering with the keypad unit, remote enablement and disablement of the lock, detection and response to a user's attempting to open the lock while under duress, and the ability to store and later transmit a history of occurrences in the lock system.
It is to meet these and other goals that the present invention is directed. No known conventional lock is believed to have the features and advantages of the inventive locks that are described in the following specification.
SUMMARY OF THE INVENTION
The invention provides a dead bolt lock that automatically blocks the extended bolt so as to prevent externally-applied force from thrusting the bolt back into the lock case. Advantageously, the dead bolt feature does not require additional consumption of energy, but is invoked by the mere extension of the bolt into its “locked” position.
The invention further provides that, in the event of certain types of physical attack, the lock responds by prolonging or perpetuating the dead bolt blocking condition. This response is ensured by the physical relation of the lock elements, and requires no additional power or control operation on the part of the lock.
Advantageously, both the automatic dead bolting feature, and the attack response feature that prolongs or perpetuates the dead bolting state, are provided using essentially the same mechanical elements, thus reducing the number of parts required for construction of the lock and reducing its fabrication cost.
The invention also provides a “push-pull” lock with a bolt whose motion in both directions is stopped in response to detection of a rise in motor current above a certain level. A cushioning arrangement allows the current limiting feature to be implemented without risk of damage to the motor, gear teeth or other drive components.
A re-locker arrangement involves an angled flange that is part of a motor-supporting bracket. When the flange is pressed with a force high enough to allow a drill to begin to remove material from a hard protective plate, the flange breaks plastic pins to release a spring-biased re-locker wire to block the bolt from being withdrawn. Further, when the wire is in the dead bolting position, an extension of the re-locker wire engages a ridge in the lock's case to prevent the re-locker from being manipulated back to its original position.
The invention also provides a lock system in which a lock controls the position of a bolt works blocking element that selectively engages a lever-driven mechanism that blocks and unblocks the door from being opened. A sensor switch, preferably located within the bolt works mechanism, tells the lock when the mechanism has been moved into a secured position, so that the lock automatically re-locks the lock (extends the bolt and moves the bolt works blocking element to engage the lever-driven mechanism). In this manner, the user does not have to carry out a second step of manually extending the bolt.
Finally, the invention provides various security enhancement features, such as a novel keypad tampering detection and response system, a remote enable/disable unit, a duress detection and response unit, a low battery sensing arrangement, a bolt extension indicator, an easily adjustable bolt throw feature, and an audit trail feature.
These and other features and advantages of the invention will be apparent to those skilled in the art upon a reading of the accompanying Detailed Description with reference to the accompanying drawing figures.
REFERENCES:
patent: 4926664 (1990-05-01), Gartner et al.
patent: 5020345 (1991-06-01), Gartner et al.
patent: 5033282 (1991-07-01), Gartner et al.
patent: 5473922 (1995-12-01), Bair et al.
patent: 5640862 (1997-06-01), Remenicky
patent: 5709114 (1998-01-01), Dawson et al.
patent: 5845523 (1998-12-01), Butterweck et al.
Cuenot Cedric
Dexet Christophe
Urschel Ned
Wicht Jacques
Barrett Suzanne Dino
Jacobson Price Holman & Stern PLLC
Sargent & Greenleaf, Inc.
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