Locks – Operating mechanism – Using a powered device
Reexamination Certificate
1998-07-13
2001-10-02
Gall, Lloyd A. (Department: 3627)
Locks
Operating mechanism
Using a powered device
C070S278100, C070S30300A, C070S322000
Reexamination Certificate
active
06295849
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to electronic dial combination locks having improved tamper resistance, and more specifically to such locks wherein a locking mechanism is opened by rotation of the dial.
2. Description of the Related Art
Electronic dial combination locks allow authorized personnel to access otherwise inaccessible security regions such as safes, lock boxes, storage rooms and the like. One such class of lock is the electronic dial combination lock which uses a dial having divisions to enter a combination code to gain entrance to the secured area. The lock has a spindle journaled within the lock for both rotational and axial movement to cause a push pin located on an internal cam wheel to engage one of a plurality of pressure-sensitive switches within the lock located in an evenly-spaced circular pattern centered on the shaft's axis, each switch being capable of making a discrete, unique electrical connection. A circuit contained in the secured region senses the electrical connections and detects when a given subset of connections has been made corresponding to the lock's combination and initiates an electrical signal within the secured region. The signal may be used, e.g., to operate a solenoid to permit a conventional fence lever to engage the cam wheel such that a bolt within the lock may be withdrawn, such as in a safe door. Such a lock is shown and described in U.S. Pat. No. 4,745,784. In the lock of that patent, when the correct combination is entered, the solenoid releases a fence lever so that a nose part formed thereon falls by gravity onto the circumferential surface of a cam wheel. The cam wheel is rotated by the combination dial until the nose part on the fence lever engages the slot in the circumference of the cam wheel to allow withdrawal of the bolt in the locking mechanism.
It has been recognized heretofore that it would be desirable to have a positive drive of the fence toward the tumbler wheel gates and the lever nose toward its cam wheel slot to ensure operation of the lever on entry of the combination. Generally these locks have employed a cam mechanism operated off of dial rotation to drive its fence lever toward the wheel once on each rotation of the dial. Such a lock is illustrated in U.S. Pat. No. 4,910,981. However, there is the possibility of learning something about the lock's internal parts from such regular impacting of the wheel by this fence or unauthorized manipulation of the lock by lock experts.
There is thus a need for a dial combination lock which does not allow an unauthorized user to obtain information about the characteristics of the gate tumbler wheels or the slotted cam wheel through manipulation of the combination dial and fence lever. Additionally, there is a need for a combination lock which prevents engagement of the fence lever with the tumbler wheels or the cam wheel until such time as the correct combination has been dialed into the lock mechanism and the nose part on the lever is aligned with the slot on the cam wheel. There is also a need for a combination lock which provides for positive movement of the lever into engagement with the slot in the cam wheel upon alignment through rotation of the combination dial.
SUMMARY OF THE INVENTION
The present invention provides a high security electronic dial combination lock which provides improved means for minimizing tampering, and for providing more predictable operation of the lock by positively engaging the fence lever with the cam wheel when the nose part on the fence lever and the slot in the cam wheel are properly aligned.
These and other objects of the present invention are accomplished preferably in an electronic combination lock which allows access to a closed or secure location wherein the lock includes a locking mechanism for operating between a locked condition and an unlocked condition. A rotatable cam wheel has a circumferential surface portion defining a slot such that rotation of the cam wheel moves the slot. A movable lever is coupled to the locking mechanism for changing the condition of the locking mechanism from the locked condition to the unlocked condition and is pivotably movable into and out of engagement with the cam wheel. The movable lever engages the cam wheel such that rotation of the cam wheel changes the condition of the locking mechanism. Means are included for releasably maintaining the pivotable lever in a position substantially disengaged from the cam wheel. Means are also included of removing the lever from its disengaged position for engaging the lever with the cam wheel so that rotation of the cam wheel changes the locking mechanism from the locked condition to the unlocked condition.
With the lock described herein, the lever is maintained in the disengaged position until the proper code is received by the lock. This serves the distinct purposes of ensuring that the lever does not engage the cam wheel until such time as the proper code has been entered and also that the lever is properly aligned with the cam wheel to allow proper engagement therebetween. Therefore, contact between the lever and the cam wheel cannot be used to obtain information about the characteristics of the cam wheel simply by rotating the combination dial. The means for moving the lever from its disengaged position to engage the cam wheel provides positive movement of the lever for engaging the cam wheel so that engagement between the fence lever and the can wheel is not dependent on the force of gravity.
In a preferred embodiment, a solenoid is activated upon entry of to proper combination code for moving a detent into position to be contacted by a boss on the cam wheel. Upon contact with the detent, further rotation of the cam wheel moves the entire solenoid housing which in turn moves a cantilevered portion of the lever so that a nose part on the lever properly engages the slot on the cam wheel. The combination of the boss on the cam wheel, the configuration of the solenoid housing and the cantilevered portion of the lever are such that the slot in the cam wheel and the nose part on the lever are properly aligned when the lever is moved into contact with the cam wheel.
A relock may be included to hold the lever in its disengaged position even after the solenoid or other parts of the lock are disabled or otherwise affected such as by tampering. In such a case, the locking mechanism thereafter cannot be moved into the unlocked condition.
Skilled practitioners will obtain a more complete understanding of the present invention from a review of the following detailed description of a preferred embodiment, in conjunction with the drawings, of which the following is a brief description.
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Cutter Larry I.
Gartner Klaus W.
Phillips Peter J.
Gall Lloyd A.
Masco Corporation
Oppenheimer Wolff & Donnelly LLP
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