Patent Application
20060059965
The present invention relates to lock cylinders, and more particularly, to an improved rekeyable lock cylinder.
It is well known in the art to provide a door hardware assembly that is operable to maintain a door in a closed position by selectively securing the door to a doorframe. It is equally well known to provide a door hardware assembly that is capable of being locked to selectively prevent operation of the door hardware assembly. As can be appreciated, by preventing operation of the door hardware assembly, the door will remain closed and in a locked condition. Such conventional door hardware assemblies generally include a handle assembly, lock cylinder, and key, whereby the key is operable to selectively lock the lock cylinder to prevent operation of the door handle assembly and maintain the door in the closed and locked condition.
The lock cylinder includes a cylinder plug rotatably supported in a cylinder housing. A set of pins extend between the cylinder plug and the cylinder housing to selectively lock and unlock the lock cylinder. The lock cylinder is designed to matingly receive a key, whereby the key is operable to change the lock cylinder between a locked and unlocked condition. As can be appreciated, the key is specific to the particular lock cylinder so as to prevent unwanted operation of the door handle assembly.
The lock cylinder commonly includes a plurality of pin assemblies, whereby each pin assembly includes an upper pin slidably disposed within an upper bore formed in the cylinder housing and a lower pin slidably disposed within a lower bore formed in the cylinder plug. A shear line is defined between the cylinder plug and cylinder housing. The key is used to selectively lock and unlock the lock cylinder, whereby raised portions or bitings disposed on the key are operable to engage the upper and lower pins to properly align the pin interface with shear line to permit rotation of the cylinder plug within the cylinder housing. It may be desirable to “reset” or “rekey” the lock cylinder, without having to replace the entire mechanism. Rekeying of a conventional lock cylinder provides the lock cylinder with a new key that is operable to lock and unlock the re-configured lock cylinder, while concurrently prohibiting further use of the old key.
In a re-keying operation, the upper and lower pins are replaced to vary the relative heights of each of the upper and lower pins which corresponds to the new key. In this regard, a new key having raised portions or bitings commensurate with the new pin heights of each pin assembly, is required to properly align the pin interface within the shear line. Once the new pins are installed, the lock cylinder will no longer permit rotation of the door handle assembly if the old key is used in the lock cylinder. As can be appreciated, the old key is not commensurate with the new pin heights, and therefore will not properly align the first and second shear zones of the respective pin assemblies.
While conventional lock cylinders adequately provide for a re-keying operation of a lock cylinder, they suffer from the disadvantage of requiring at least partial disassembly of the lock cylinder and typically require a specialized technician, such as a locksmith, to perform the re-keying operation. Further, conventional lock cylinders suffer from the disadvantage of requiring multiple pin heights and combinations thereof to properly re-key the cylinder. Further yet, conventional re-keying kits require door hardware manufacturers to produce varying pin heights for each kit, thereby overproducing the required number of individual pins to simply re-key one lock cylinder.
Therefore, a lock cylinder that provides for a re-keying operation without requiring disassembly of the lock cylinder is desirable in the industry. Furthermore, a lock cylinder that is capable of being re-keyed without replacing the existing components is also desirable. Further yet, a lock cylinder that provides for a re-keying operation without requiring a plurality of additional pins with varying pin heights is also desirable.
In accordance with one aspect of the present invention, a lock cylinder is provided which includes a cylinder housing having a first bore formed along a first longitudinal axis, a cylinder plug rotatably disposed within the first bore, and a pin assembly disposed within the cylinder housing and the cylinder plug. The pin assembly is operable to selectively lock the inner cylinder relative to the outer cylinder. The pin assembly includes an upper pin disposed in a pin bore formed in the cylinder housing and a lower tumbler pin assembly having a pair of pins disposed and slidably supported within a pin bore formed in the cylinder plug. A coupling element is interposed between the pair of pins and selectively rotatable between a coupled position wherein the pair of pins are fixed with respect to one another and a free position wherein the pair of pins are positionable with respect to one another for varying a height of the tumbler pin assembly. A camming system is operably coupled between the cylinder housing and the tumbler pin assembly to enable selective rotation of the coupling elements between the coupled position and the free position.
In accordance with one aspect of the present invention, a method of rekeying a lock cylinder is provided in which a valid key is inserted into a keyway in a cylinder plug so that the cylinder plug can be rotated with respect to the cylinder housing from a home position to a learn position. A pin assembly within a pin bore formed in the cylinder plug is rotated from a fixed position to a free position such that a height defined by first and second pins of the pin assembly is adjusted. The valid key is extracted from the keyway and a replacement key is inserted into the keyway. The pin assembly is rotated within the pin bore to the coupled position to fix the height of the pin assembly. The cylinder plug is rotated to the home position and the replacement key is removed.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
With reference now to the drawings, lock cylinder assembly 10 includes a cylinder housing 12 having a cylindrical cavity 14 formed along a longitudinal axis thereof and a cylinder plug 16 having a keyway 18 formed along the longitudinal axis thereof which is rotatably supported within the interior cavity 14 of the cylinder housing 12. A chimney 20 extends upwardly from cylinder body 22. A set of pin bores 24 extend through chimney 20 and terminate at interior cavity 14. Likewise, a set of pin bores 26 are formed in cylinder plug 16 to extend between keyway 18 and an outer surface of the cylinder plug 16. As previously indicated the cylinder 16 is rotatably supported within the cylinder housing 12 such that pin bores 24 formed in chimney 20 are aligned with pin bores 26 when the cylinder plug 16 is in a home position.
Lock Cylinder assembly 10 further includes a set of tumbler pins 28 and a set of springs 30 disposed and slidably supported within pin bore 24 at cylinder housing 12. A cap 32 is disposed on top of chimney 20 for releasbly retaining pins 28 and springs 30 therein. Another set of tumbler pin assemblies 34 are disposed and slidably supported within pin bore 26. As best seen in
Spring 40 is interposed between adjacent faces of carrier body 42 and pin body 48. As presently preferred, spring 40 takes the form of a generally unshaped leaf spring adapted to a flex within the confines of blind bore 44. However, one skilled in the art will recognize that other spring elements which provide an opposed biasing force between pin carrier 36 and inner pin 38 may be suitably employed in the present invention.
Pin carrier 36 may be selectively rotatable with respect to inner pin 38 on pin body 48. A coupling element is interposed between the pin carrier 36 and the inner pin 38 which in a coupled position, the coupling element affixes the inner pin 38 with respect to the pin carrier 36 such that the overall height of the tumbler pin assembly 34 is fixed. Pin carrier 36 may be rotated relative to inner pin 38 to an uncoupled or free position. In the free position, the pin carrier 36 and the inner pin 38 may slide axially within pin bore 26 independent of one another, thereby allowing for adjustment of the pin height of pin tumbler assembly 34.
As presently preferred, the coupling element takes the form of an arcuate gear set. Specifically with reference to
Pin carrier 36 has a cam arm 60 extending from carrier body 42. A comb 62 having a set of fingers 64 extends through a set of apertures 66 formed in cylinder housing 22 and a set of apertures 68 formed in cylinder plug 16 so as to engage cam arm 60 as best seen in
Comb 72 is disposed on a side of housing body 22 opposite comb 62. Comb 72 has a set of fingers 74 extending therefrom which are adapted to be received through a set of apertures 76 formed in housing body 22 and a set of apertures 78 formed in cylinder plug 16. Fingers 74 extend through apertures 78 to impinge upon the pin carrier 36 and maintain the tumbler pin assembly 34 in a coupled position when the lock cylinder 10 and not the learn position (i.e., in the home position or the upright position).
With reference now to
To place the lock cylinder 10 into a learn mode, an authorized key K is inserted into the keyway 18 thereby permitting relative rotation of the cylinder plug 16 within cylinder housing 12 in a clockwise direction as shown in
The present invention has been described with reference to a preferred embodiment. However, one skilled in the art will recognize that the present invention may be modified without departing from the spirit and scope of the invention. For example, the preferred embodiment discloses a camming system for rotating the pin carrier with respect to the inner pin. However, other suitable mechanisms may be utilized which provide relative rotation of the pin carrier within the cylinder plug bore. By way of example, the comb 62 may be replaced by suitable gear rack which engages a set of gear teeth formed on the outer surface of the pin carrier for providing relative rotation. Similarly, since the present invention contemplates relative rotation between the pin carrier and the inner pin, other suitable mechanisms may be provided which rotate the inner pin with respect to the pin carrier. Likewise, the present invention has been illustrated as a five pin lock cylinder. However, one skilled in the art will readily recognize that the teachings of the present invention may be readily applied to provide any number of pin assemblies as dictated by the requirements of a given application.
Accordingly, the description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
