The present invention relates to mechanical keyed lock cylinders and particularly to lock cylinders that can be master keyed. More particularly, it relates to mechanical keyed lock cylinders capable of having user keys and master keys rekeyed without disassembly of the lock cylinder.
When rekeying a cylinder using a traditional cylinder design, the user is required to remove the cylinder plug from the cylinder body and replace the appropriate pins so that a new key can be used to unlock the cylinder. This typically requires the user to remove the cylinder mechanism from the lockset and then disassemble the cylinder to some degree to remove the plug and replace the pins. This requires a working knowledge of the lockset and cylinder mechanism and is usually only performed by locksmiths or trained professionals. Additionally, the process usually employs special tools and requires the user to have access to pinning kits to interchange pins and replace components that can get lost or damaged in the rekeying process. Finally, professionals using appropriate tools can easily pick traditional cylinders.
The present invention overcomes these and other disadvantages of conventional lock cylinders. The lock cylinder of the present invention operates in a transparent way that presents the familiar experience of inserting a key and rotating the key in the lock cylinder, as with current cylinders. However, in the present invention, that same familiar experience is used to rekey the lock cylinder. Thus, the user does not require any special knowledge, training, or tools to rekey the lock cylinder of the present invention.
Managers of multi-unit complexes such as, for example, apartment buildings or hotels, find the use of rekeyable locks to be particularly advantageous. In the past, when a user's lease expired, the manager or landlord had to change the locks to protect the security of the subsequent tenant by preventing the previous user from reentering the property. Rekeyable locks allow the manager to rekey the lock, thereby rendering the previous user's key obsolete, without removing the lock, saving time and money.
Managers also need to have access to their property when the current user is not available or when the user's key is lost or stolen. Rather than carry a duplicate key for each unit, which could become very cumbersome in large complexes, managers employ master keying systems that use special locks capable of being operated by two different keys. Such master keying systems allow each user to have a unique key while, at the same time, allowing the manager to operate all of the locks in a complex with one, or at most a few, master keys.
Unfortunately, as with conventional locks, master keying system locks typically require the manager to remove the cylinder mechanism from the lockset and then disassemble the cylinder to some degree to remove the plug and replace the pins. Access to master key system locks that can be quickly and easily rekeyed would be very advantageous to property managers. Even greater advantage would be derived from a master key system that allows both the user key and master key to be rekeyed.
Smith, in U.S. Pat. No. 4,741,188, discloses a rekeyable master keying system with a pin and tumbler design that uses master shims or wafers positioned in between the pins of the lock cylinder to establish a shear line for the master key and user keys. In Smith's cylinder, each rekeying operation involves completely removing one of the wafers from the lock cylinder. Unfortunately, that means that only a limited number of rekeying operations are available. Once a particular key bitting has been used, it cannot be reused without disassembling the lock cylinder to reinstall the missing wafer(s) necessary for that particular bitting. Moreover, the user keys and master keys require different notches to be cut in the spine of the key to accommodate the wafers at different pin positions, which adds complexity.
The present invention overcomes these disadvantages and others by providing a mechanical keyed lock cylinder capable of rekeying the user and master keys without completely eliminating previously used key combinations, thereby providing increased usability. In addition, the user key and master key utilize separate internal parts, thereby providing increased security.
The present invention includes a method of rekeying a master keyable lock cylinder having a keyway and a longitudinal axis. The method includes the steps of providing a plurality of key followers and a first plurality of racks coupled to the plurality of key followers wherein the first plurality of racks has a first configuration that aligns the first plurality of racks along a common axis in response to the presence of a first key with a first bitting in the keyway. The method also includes the steps of providing a second plurality of racks coupled to the plurality of key followers, wherein the second plurality of racks has a second configuration that aligns the second plurality of racks along a common axis in response to the presence of a second key with a second bitting in the keyway. Another step includes reconfiguring the first plurality of racks to align along a common axis in response to insertion of a third key with a third bitting while maintaining the second configuration of the second plurality of racks.
The method further includes the step of coupling one rack of the first plurality of racks and one rack of the second plurality of racks to the same key follower. The step of reconfiguring includes the step of decoupling the first plurality of racks from the plurality of key followers, and the step of decoupling includes the step of moving the first plurality of racks parallel to the longitudinal axis relative to the key followers.
The above described method can be used with a rekeyable master keyable lock cylinder that includes a keyway, a plurality of key followers, a plurality of user racks coupled to the plurality of key followers and configured to unlock the lock in response to insertion of a valid user key in the keyway, and a plurality of master racks coupled to the plurality of key followers and configured to unlock the lock in response to insertion of a valid master key in the keyway, wherein the plurality of key followers, the plurality of user racks and the plurality of master racks cooperate to allow the user key to be rekeyed independently of the master key and to allow the master key to be rekeyed independently of the user key.
One embodiment of a rekeyable master keyable lock cylinder 10 according to the present invention is illustrated in
As illustrated in
As illustrated in
As illustrated in
The locking bar 28, as illustrated in
An exemplary pin or key follower 18 is illustrated in
An exemplary engagement of rack gear teeth 92 with the key follower gear teeth 106 is illustrated in
As the key is rotated, the locking bar 28 cams out of the 1st locking bar recess 38. As the locking bar 28 cams out of the recess 38, the V-shaped tabs 86 are pushed against the master rack guide channels 98M which, in turn, guide the V-shaped tabs 86 into the user rack receiving slot 102U. When the tabs 86 enter the user rack receiving slots 102U, the locking bar 28 clears the shear line 30, allowing the plug assembly 14 to rotate in the housing 12.
If a non-valid key is inserted, the racks 24U will be moved to a position wherein at least one of the receiving slots 102U will not align along the common axis. In that case, attempting to rotate the plug assembly 14 in the housing 12 will force the V-shaped tab 86 to engage the opposing guide channel of the misaligned rack 24U instead of the receiving slot 102U, thereby preventing the locking bar 28 from camming out of the first locking bar recess 38. With the locking bar 28 unable to cam out of the recess 38, the locking bar 28 remains disposed across the shear line 30, thereby preventing the plug assembly 14 from rotating in the housing 12.
The same functionality applies to the master key as well. When a valid master key is inserted, the master racks 24M are aligned to receive the V-shaped tabs 86 in the receiving slots 102M. Rotation of the plug assembly 14 in the housing 12 pushes the tabs 86 along the user rack guide channels 98 and into the master rack receiving slots 102M, thereby clearing the locking bar 28 from the shear line 30 and allowing the plug assembly 14 to rotate in the housing 12.
An invalid master key incurs the same blocking action of the V-shaped tabs 86 as the invalid user key, keeping the locking bar 28 disposed across the shear line 30.
Rekeying the lock cylinder 10 to accept a new user key is accomplished by disengaging the user racks 24U from the key followers 18 and replacing the original valid key with a new valid key having different bitting, and then reengaging the user racks 24U with the key followers 18. Disengaging the racks 24U from the key followers 18 allows the user racks 24U to move vertically to a new position relative to the key follower 18 based on the bitting of the new key.
When a user inserts a valid user key the user racks 24U align along a common axis, as previously discussed. The user can then rotate the plug assembly 14 to a predetermined position, the learn position. When the plug assembly 14 is in the learn position, the user inserts a rekeying tool 64 into the tool receiving aperture 54 and pushes against the carrier 26 toward the rear of the plug body 16, as illustrated in
When the carrier 26 is displaced longitudinally, the locking bar 28 also moves longitudinally toward the rear of the plug body 16, as illustrated in
With the boss 44 in the notch 84, the plug assembly 14 is held in the learning position and the carrier 28 is retained in the longitudinally displaced position. At this point, the master racks 24M are still engaged with the key followers 18, thereby retaining their respective keying positions to ensure that the valid master key will continue to operate the lock cylinder 10. When the first valid key is removed, the master racks 24M move up and down with the key followers 18 according to the key bitting. The user racks 24U, on the other hand, are disengaged from the key followers 18 and locked in position by the learning bullets 56. As such, they are unaffected by the movement of the key followers 18.
When second key is inserted and rotated back to the home position, the locking bar 28 cams out of the 2nd locking bar recess 42, disengaging the locking bar retaining boss 44 from the notch 84. The carrier spring 32 biases the carrier 28 back to its original position, thereby reengaging the user racks 24U with the key followers 18. Since the user racks 24U were aligned along the common axis when they reengaged the key followers 18, they automatically assume the appropriate position to operate with the second key. Thus the second key becomes the valid user key and the original valid key is no longer operable.
The same functionality applies to rekeying the master key. To rekey a master key, the plug assembly 14 is rotated to the learn position and a rekeying tool 64 is inserted into the slot 66 in the rear of the plug body 16. The carrier 26 moves toward the face 50 of the plug body 16, moving the master racks 24M out of engagement with the key followers 18. The second notch 84 on the locking bar 28 engages the boss 44 to retain the carrier and racks 24U, 24M in position. In all other respects, the master key rekeying process is the same as the user key rekeying process.
While the present invention has been described with particular reference to a preferred embodiment of a lockset mechanism, one skilled in the art will recognize that the present invention may be readily adapted to embodiments other than those described with reference to the preferred embodiments. Furthermore, those skilled in the art will readily recognize from the foregoing discussion and accompanying drawings and claims, that changes, modifications and variations can be made in the present invention without departing from the spirit and scope thereof as defined in the following claims.
The present invention claims priority to Provisional Patent Application Ser. No. 61/545,241, filed Oct. 10, 2011, titled “Master Keyable Rekeyable Smart Key”.
Number | Date | Country | |
---|---|---|---|
61545241 | Oct 2011 | US |