WO2004079134A1

WO2004079134A1 - Rekeyable lock cylinder assembly with adjustable pin lengths

Info

Publication number: WO2004079134A1
Application number: PCT/US2004/006320
Authority: WO
Inventors: Donald J. Segien
Original assignee: Newfrey Llc
Priority date: 2003-03-04
Filing date: 2004-03-03
Publication date: 2004-09-16
Also published as: MXPA05009388A; CA2517887A1; US7634931B2; BRPI0408088B1; CA2517887C; CN1774553A; CN1774553B; US20050172687A1; BRPI0408088A

Abstract

Certain exemplary embodiments of the present invention provide a rekeyable lock cylinder, comprising: a cylinder body having a longitudinal axis; and a plug assembly and disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said first plug pin portion from said second plug pin portion. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. This abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Description

REKEYABLE LOCK CYLINDER ASSEMBLY WITH ADJUSTABLE PIN LENGTHS

Brief Description of the Drawings

The invention and its wide variety of potential embodiments will be readily understood via the following detailed description of certain exemplary embodiments, with reference to the accompanying drawings in which:

FIG. 1 is a front perspective assembly view of an exemplary embodiment of a system of the present invention;

FIG. 2 is a perspective view of an exemplary embodiment of an adjustable length pin assembly of the present invention;

FIG. 3 is a perspective view of an exemplary embodiment of an adjustable length pin portion of the present invention;

FIG. 4 is a top view of an exemplary embodiment of a system of the present invention in a normal mode;

FIG. 5 is a top view of an exemplary embodiment of a system of the present invention in a learn mode;

FIG. 6 is a perspective view of an exemplary embodiment of a cylinder assembly of the present invention;

FIG. 7 is a side view of an exemplary embodiment of a key and an adjustable length pin assembly of the present invention;

FIG. 8 is a side view of an exemplary embodiment of an adjustable length pin assembly of the present invention; and

FIG. 9 is a flow chart of an exemplary embodiment of method of the present invention. Detailed Description

Certain exemplary embodiments of the present invention provide a rekeyable lock cylinder, comprising: a cylinder body having a longitudinal axis; and a plug assembly and disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said first plug pin portion from said second plug pin portion.

Certain exemplary embodiments of the present invention provide a method for keying a lock cylinder, comprising the activities of: for a lock cylinder comprising a cylinder body having a longitudinal axis, said lock cylinder further comprising a plug assembly disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said plurality of first plug pin portions from said plurality of second plug pin portions: while said plurality of first plug pin portions are not engaged with said plurality of second plug pin portions, inserting a first key into said plug assembly, said plurality of second plug pin portions relocated by said first key; and after inserting said first key into said plug assembly, engaging said plurality of first plug pin portions with said plurality of second plug pin portions.

Certain exemplary embodiments of the present invention provide a system comprising: a rekeyable lock cylinder coupleable to a door, said rekeyable lock cylinder comprising: a cylinder body having a longitudinal axis; and a plug assembly and disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said first plug pin portion from said second plug pin portion; and a backing rack releasing tool receiving aperture defined by said rekeyable lock cylinder; and a key adapted to operate said rekeyable lock cylinder.

FIG. 1 is a front perspective assembly view of an exemplary embodiment of a system 100 of the present invention. System 100 can comprise a valid key 110, a lock cylinder assembly 120 defining a longitudinal axis A-A, a plug assembly 140, and a plug clip 190 that can resist relative longitudinal movement between cylinder assembly 120 and plug assembly 140. Cylinder assembly 120 can comprise a cylinder body 122, a cylinder inner surface 124, and a longitudinally spaced, radially-aligned plurality of cylinder pin chambers (not shown) each at least partially containing a corresponding cylinder pin and spring (not shown). Plug assembly 140 can comprise a plug body 142 that at least partially defines a plurality of longitudinally spaced, radially aligned plug pin chambers 144, a plug clip retainer 148, a plug face 150, a keyway 152, and a plurality of adjustable length plug pin assemblies 180. Plug assembly 140 also can comprise a backing rack assembly 160 that can comprise a backing rack 162, a backing rack spring 164, a plug pin retainer 166, and a ramp contact surface 168. Plug assembly 140 can engage a latch mechanism (not shown) attached to a door (not shown).

As shown, plug body 142 can resemble an elongated shape having a longitudinal cross section resembling approximately three-quarters of a circle. Backing rack 162 can resemble an elongated shape having a longitudinal cross section resembling approximately one-quarter of a circle. Note that as long as plug body 142 and backing rack 162 cooperate to form approximately a completely circular longitudinal cross section, there is no particular requirement about what portion of the circle each provides.

Upon insertion of valid key 110 into keyway 152 of plug assembly 140, plug pin assemblies 180 can relocate to conform to the cut of the key, thereby relocating cylinder pins (not shown) located in cylinder 122 such that a shear line (not shown) can be established, allowing plug assembly 140 to rotate within cylinder assembly 120. System 100 can be installed in a door to lock the door to prevent opening unless a valid key is used to rotate plug assembly 140 from a lock position to an unlock position.

Upon rotation of plug assembly 140 within cylinder 122 to a learn position, the location of backing rack assembly 160 relative to the plug body 142 can change such that plug pin assemblies 180 can change length. While in the learn position, a new key (not shown) can be inserted.

As plug assembly 140 is rotated away from the learn position, one or more plug pin assemblies 180 can adjust in length to conform to differences in the cut of the new key versus the old key, and backing rack assembly can at least partially restrain the plug pin assemblies to the new plug pin lengths. Thereby, system 100 can learn the new key and be rekeyed to the new key without requiring disassembly, the use of any specialized rekeying tools, and possibly without the use of any rekeying tools whatsoever.

In an alternative embodiment, a moveable stop (not shown) coupled to either cylinder body 122 or plug body 142, can require actuation (such as via pressure applied using a paper clip inserted through an aperture (not shown) in cylinder assembly 120) to allow plug assembly 140 to rotate to the learn position.

FIG. 2 is a perspective view of an exemplary embodiment of a plug pin assembly 180 of the present invention. Plug pin assembly 180 can comprise an upper plug pin portion 182 and a lower plug pin portion 184 that can cooperate to form a plug pin having a longitudinal axis C-C. A plug pin spring 186 can be disposed to longitudinally increase a length L of plug pin assembly 180 and/or to separate upper plug pin portion 182 from lower plug pin portion 184 along direction B-B and/or along axis C-C. An upper guide surface 183 and/or a lower guide surface 185 can cooperate with an inner wall of plug pin chamber 144 (shown in FIG. 1) to prevent rotation of plug pin assembly 180, upper plug pin portion 182, and/or lower plug pin portion 184 about axis C-C. A cylinder pin engagement surface 187 can contact and/or cooperate with a cylinder pin (not shown) to form at least a portion of a shear line (not shown) that can allow plug assembly 140 (shown in FIG. 1 ) to rotate within cylinder assembly 120 (shown in FIG. 1 ).

FIG. 3 is a perspective view of an exemplary embodiment of an exemplary plug pin portion of the present invention, such as upper plug pin portion 182 or lower plug pin portion 184. The plug pin portion can comprise at least one row, and possibly two rows (as shown), containing a plurality of teeth 188, which can be spaced a distance S from peak-to-peak and/or from valley-to-valley. Spacing S can be equivalent to a key cut depth increment. A contour of each tooth 188 can be predetermined to optimize operation of pin assembly 180 (shown in FIG. 2).

FIG. 4 is a top view of an exemplary embodiment of a system 100 of the present invention in a normal mode, which can correspond to either a lock position or an unlock position. As shown, plug body 142 defines a plurality of plug pin chambers 144 that are shaped to cooperate with plug pin guide surfaces 183, 185 (shown in FIG. 2) to restrain movement of plug pin assemblies 180 to certain directions with respect to plug body 142. Backing rack assembly 160, which can comprise backing rack 162, backing rack spring 164, pin restrainers 165, and ramp contact surface 168, can, in cooperation with cylinder cap 125, further restrain movement of plug pin assemblies 180 with respect to plug body 142. Thus, referring to FIGS. 2 and 4, when system 100 is in a normal mode, pin restrainers 165 can resist relative movement of upper plug pin portion 182 with respect to lower plug pin portion 184 along direction B-B, thereby preventing a change in length L of plug pin assembly 180, and orienting plug pin assembly 180 perpendicular to an axis of the plug assembly. Thus, upper plug pin portion 182 and lower plug pin portion 184 can emulate a solid pin of a given length, having an axis C-C or parallel thereto.

FIG. 5 is a top view of an exemplary embodiment of a system 100 of the present invention in a learn mode, which can correspond to the learn position described previously. Backing ramp 126, which can be coupled to cylinder cap 125, can engage with ramp contact surface 168 of backing rack 162 function as a backing rack relocator that relocates backing rack 162 and compresses backing rack spring 164. In an unshown alternative embodiment, backing ramp 126 can be recessed into cylinder cap 125, such that backing rack 162 moves toward cylinder cap 125 as system 100 enters the learn mode. In another unshown alternative embodiment, backing rack 162 can remain stationary and plug body 142 can move axially (i.e., along, and/or parallel to, a longitudinal axis of cylinder body 122, in either direction (i.e., either inward or outward) with respect to backing rack 162, as system 100 enters the learn mode. In yet another unshown alternative embodiment, both backing rack 162 and plug body 142 can move axially, yet move relative to each other axially as well. Regardless of how the relative movement is generated between backing rack 162 and plug body 142 along and/or parallel to the longitudinal axis of cylinder body 122, referring to FIGS. 2 and 5, pin restrainers 165 of backing rack assembly 160 can be disposed to allow relative movement of upper plug pin portion 182 with respect to lower plug pin portion 184 along direction B-B, thus allowing a change in length L of plug pin assembly 180.

Considering further this relative pin portion movement, and referring to FIGS. 1 and 2, as pin spring 186 biases upper plug pin portion 182 apart from lower plug pin portion 184, upper plug pin portion 182 is constrained in its motion along axis C-C by cylinder inner surface 124, and lower plug pin portion 184 is constrained in its motion along axis C-C by the key. At this point, the key may be removed. As the key is removed, upper plug pin portion 182 can remain at least partially constrained in its motion along axis C-C by cylinder inner surface 124, and lower plug pin portion 184 cam be somewhat free, thereby allowing relative movement between and/or separation of upper plug pin portion 182 and lower plug pin portion 184. This relative movement can cause at least a partial disengagement of the teeth of upper plug pin portion 182 from the teeth of lower plug pin portion 184.

As the key is removed, each lower plug pin portion 184 can ride up and down the ramps of the key (see FIG. 7). Once the key is completely removed, each lower plug pin portion 184 can be constrained by features (not shown) within the plug body.

Referring to FIGS. 1 , 2, and 7, as a new key 110 is inserted into keyway 152, at least one lower plug pin portion 184 can ride up and down the ramps of the new key. When the new key is fully inserted, each plug pin assembly 180 can be compressed to the correct length for the new key to operate plug assembly 140 within cylinder assembly 120 (i.e., the lockset).

Referring to FIGS. 1-5, as the new key is turned to rotate the plug assembly in reverse and away from the learn position, ramp contact surface 168 rides down the backing rack ramp 126 causing the plug pin retainer 166 to relocate into a plug pin restraining position. At this point, the teeth of each plug pin assembly 180 are engaged and/or meshed, and the length of each plug pin assembly 180 is fixed. As the plug continues to turn away from the learn pos on, any movable stop (not shown) that was actuated can return to its neutral pos on, thereby resisting a rotation of plug assembly 140 toward the learn pos on.

FIG. 6 is a perspective view of an exemplary embodiment of a cylinder assembly 120 of the present invention. Cylinder assembly 120 can comprise a cylinder body 120, a cylinder inner surface 124 that can contain plug assembly 140 (shown in FIG. 1 ). Coupled to cylinder cap 125 can be a backing rack ramp 126 that can serve to relocate backing rack assembly 160 and/or backing rack 162 (shown in FIGS. 1 , 4, 5).

FIG. 7 is a side view of an exemplary embodiment of a key 110 and plug pin assembly 180 of the present invention. Adjustable length plug pin assembly 180 can cooperate with flats 112 of key 110, which can be separated by key ramps 114.

FIG. 8 is a side view of an exemplary embodiment of an alternative plug pin assembly of the present invention. Alternative adjustable length plug pin assembly 280 can include an upper plug pin portion 282, an upper plug pin cap 283, a lower plug pin portion 284, and a lower plug pin cap 285. Alternative plug pin assembly 280 can also include a plug pin spring 286 disposed around upper plug pin portion 282 and lower plug pin portion 284, and bearing against upper plug pin cap 283 and lower plug pin cap 285.

FIG. 9 is a flowchart of an exemplary embodiment of a method 200 of the present invention. At activity 310, a valid key is inserted into the plug assembly, thereby relocating plug pins and cylinder pins to establish and/or align with a shear line, and thereby allow rotation of the plug assembly within the cylinder assembly.

At activity 320, torsion is applied to the key to rotate the plug assembly within the cylinder body from a locked position to an unlocked position and/or to a rekeying position. The unlocked position can occur at any orientation with respect to the locked position, such as from approximately 10 degrees to approximately 250 degrees, including each number therebetween, such as approximately 30.05, 62, 90, 118.7, 150.03, 180, and/or 224 degrees, etc. The rekeying position can occur at any orientation with respect to the first locked position, such as from approximately 10 degrees to approximately 250 degrees, including each number therebetween, such as approximately 30.05, 62, 90, 118.7, 150.03, 180, and/or 224 degrees, etc.

At activity 330, as the plug assembly is rotated to the rekeying position, the backing rack ramp of the cylinder assembly can contact the ramp contact surface of the backing rack. Referring to FIGS. 4 and 5, this contact can cause the backing rack to move longitudinally, so that the plug pin retainers lose contact with the plug pins. Referring to FIG. 2, this loss of contact between the plug pin retainers and the plug pins can allow one or more plug pin springs to bias its respective upper plug pin portion and lower plug pin portion apart, along axis C-C and/or in direction B-B. Thus, the teeth of at least one upper plug pin portion can become disengaged from the corresponding teeth of the lower plug pin portion sufficiently to allow the plug pin assembly to lengthen along axis C-C. At activity 340, a new key having a different cut pattern can be inserted into the keyway of the plug assembly, thereby, at activity 350, changing the length of at least one adjustable length plug pin assembly.

At activity 360, the plug assembly can be rotated in reverse away from the rekeying position (learn mode). By doing so, the ramp contact surface of the backing rack can ride down the backing rack ramp of the cylinder assembly until eventually the ramp contact surface in contact with the cylinder cap. Referring to FIGS. 4 and 5, this loss of contact between the ramp contact surface of the backing rack can cause the backing rack to move longitudinally, so that the plug pin retainers again make contact with the plug pins. Referring to FIG. 2, this restoration of contact between the plug pin retainers and the plug pins can cause the plug pin portions to compress the plug pin spring and/or to move together along axis C-C and/or in direction B-B. Thus, the teeth of at least one upper plug pin portion can become engaged with the corresponding teeth of the lower plug pin portion sufficiently to fix and/or resist change of a length of plug pin assembly as measured along axis C-C, thus learning the pattern of the new key such that the new key is required to operate the plug assembly within the cylinder assembly.

The plug assembly can continue to be rotated until it in either the lock or unlock position. Note that the lock system can be rekeyed without removing the plug clip or removing the plug body from the cylinder body. Note also that because there is no need to remove the plug assembly from the cylinder assembly, no plug follower is required for rekeying. Note also that no specialized tools are necessarily required for rekeying.

Thus, embodiments of the present invention can provide a method for rapidly rekeying a lock cylinder without the need for a plug follower or for removing the plug assembly from the cylinder assembly. Moreover, in certain embodiments of the present invention, the rekeyer is not required to remove a cylinder chimney cover, cylinder pin springs, or cylinder pins. Although the invention has been described with reference to specific exemplary embodiments thereof, it will be understood that numerous variations, modifications and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the invention. Also, references specifically identified and discussed herein are incorporated by reference as if fully set forth herein. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive.

Claims

What is claimed is:

1. A rekeyable lock cylinder, comprising:

a cylinder body having a longitudinal axis; and

a plug assembly and disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said first plug pin portion from said second plug pin portion.

2. A rekeyable lock cylinder according to claim 1 , wherein said plurality of plug pin chambers is in one-to-one correspondence with a plurality of cylinder pin chambers.

3. A rekeyable lock cylinder according to claim 1 , wherein said cylinder body comprises a backing rack relocator.

4. A rekeyable lock cylinder according to claim 1 , full rotation of said plug body within said cylinder body about said longitudinal axis in a predetermined direction resisted by a stop.

5. A rekeyable lock cylinder according to claim 1 , full rotation of said plug body within said cylinder body about said longitudinal axis in a predetermined direction prevented by a fixed stop.

6. A rekeyable lock cylinder according to claim 1 , full rotation of said plug body within said cylinder body about said longitudinal axis in a predetermined direction resistible by a movable stop.

7. A rekeyable lock cylinder according to claim 1 , said plug body rotatable within said cylinder body about said longitudinal axis between a first position and a second position, said first position causing said plug body and said backing rack to cooperatively define said plurality of plug pin chambers, said second position causing said backing rack to engage with a backing rack relocator.

8. A rekeyable lock cylinder according to claim 1 , said plug body rotatable within said cylinder body about said longitudinal axis between a first position and a second position, said first position engaging said first plug pin portion with said second plug pin portion, said second position disengaging said first plug pin portion from said second plug pin portion.

9. A rekeyable lock cylinder according to claim 1 , said plug body rotatable within said cylinder body about said longitudinal axis between a first position and a second position, said first position causing said plug body and said backing rack to cooperatively define said plurality of plug pin chambers, said second position causing each of said plurality of plug pins to elongate.

10. A rekeyable lock cylinder according to claim 0, said first plug pin portion releaseably meshable with said second plug pin portion.

11. A rekeyable lock cylinder according to claim 1 , said backing rack axially movable to allow disengagement of teeth of said first plug pin portion from teeth of said second plug pin portion.

12. A rekeyable lock cylinder according to claim 1 , further comprising a backing rack spring biased to move said backing rack axially with respect to said plug body.

13. A rekeyable lock cylinder according to claim 1 , further comprising a plug clip releaseably disposed to limit axial movement of said plug assembly with respect to said cylinder body.

14. A rekeyable lock cylinder according to claim 1 , further comprising a plug clip disposed to prevent axial separation of said cylinder body and said plug assembly.

15. A rekeyable lock cylinder according to claim 1 , further comprising a plurality of plug pin springs, each of said plug pin springs biased to extend a length of a corresponding plug pin.

16. A rekeyable lock cylinder according to claim 1 , further comprising a plurality of plug pin springs, each of said plug pin springs disposed between said first plug pin portion and said second plug pin portion.

17. A rekeyable lock cylinder according to claim 1 , further comprising a plurality of plug pin springs, each of said plug pin springs surrounding a plurality of teeth of said first plug pin portion and a plurality of teeth of said second plug pin portion.

18. A rekeyable lock cylinder according to claim 1 , further comprising a plurality of plug pin springs, each of said plug pin springs disposed between a cap of said first plug pin portion and a cap of said second plug pin portion.

19. A rekeyable lock cylinder according to claim 1 , each of said first plug pin portions further comprising a plurality of first plug pin portion teeth.

20. A rekeyable lock cylinder according to claim 1 , each of said second plug pin portions further comprising a plurality of second plug pin portion teeth.

21. A rekeyable lock cylinder according to claim 1 , each of said first plug pin portions comprising a plurality of first plug pin portion teeth, and each of said second plug pin portions comprising a plurality of second plug pin portion teeth, said plurality of first plug pin portion teeth engageable with said plurality of second plug pin portion teeth.

22. A method for keying a lock cylinder, comprising the activities of:

for a lock cylinder comprising a cylinder body having a longitudinal axis, said lock cylinder further comprising a plug assembly disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said plurality of first plug pin portions from said plurality of second plug pin portions:

while said plurality of first plug pin portions are not engaged with said plurality of second plug pin portions, inserting a first key into said plug assembly, said plurality of second plug pin portions relocated by said first key; and

after inserting said first key into said plug assembly, engaging said plurality of first plug pin portions with said plurality of second plug pin portions.

23. The method for keying a lock cylinder of claim 22, further comprising the activity of:

inserting a second key into said plug assembly, said plurality of second plug pin portions relocated by said second key

24. The method for keying a lock cylinder of claim 22, further comprising the activity of:

rotating said plug body within said cylinder body about said longitudinal axis to a movable stop.

25. The method for keying a lock cylinder of claim 22, further comprising the activity of:

inserting a rekeying tool into an aperture in a face of said plug body.

26. The method for keying a lock cylinder of claim 22, further comprising the activity of:

depressing a movable stop adapted to resist rotation of said plug body within said cylinder body about said longitudinal axis.

27. The method for keying a lock cylinder of claim 22, further comprising the activity of:

rotating said plug body within said cylinder body about said longitudinal axis from a normal position to a learn position.

28. The method for keying a lock cylinder of claim 22, further comprising the activity of:

placing said lock cylinder in a learn mode.

29. The method for keying a lock cylinder of claim 22, further comprising the activity of:

moving said backing rack along a back rack ramp.

30. The method for keying a lock cylinder of claim 22, further comprising the activity of:

moving said backing rack parallel to said longitudinal axis.

31. The method for keying a lock cylinder of claim 22, further comprising the activity of:

allowing relative movement between said plurality of first plug pin portions and said plurality of second plug pin portions parallel to said longitudinal axis.

32. The method for keying a lock cylinder of claim 22, further comprising the activity of:

allowing relative movement between said plurality of first plug pin portions and said plurality of second plug pin portions perpendicular to said longitudinal axis.

33. The method for keying a lock cylinder of claim 22, further comprising the activity of:

removing a second key from said plug assembly.

34. The method for keying a lock cylinder of claim 22, further comprising the activity of:

unlearning a second key.

35. The method for keying a lock cylinder of claim 22, further comprising the activity of:

disengaging said plurality of first plug pin portions from said plurality of second plug pin portions.

36. The method for keying a lock cylinder of claim 22, further comprising the activity of:

unmeshing said plurality of first plug pin portions from said plurality of second plug pin portions.

37. The method for keying a lock cylinder of claim 22, further comprising the activity of:

causing each plug pin from said plurality of plug pins to elongate.

38. The method for keying a lock cylinder of claim 22, further comprising the activity of:

elongating each plug pin from said plurality of plug pins.

39. The method for keying a lock cylinder of claim 22, further comprising the activity of:

aligning said second pin portions to said first key.

40. The method for keying a lock cylinder of claim 22, further comprising the activity of:

compressing each plug pin from said plurality of plug pins.

41. The method for keying a lock cylinder of claim 22, further comprising the activity of: rotating said plug body within said cylinder body about said longitudinal axis from a learn position to a normal position.

42. The method for keying a lock cylinder of claim 22, further comprising the activity of:

placing said lock cylinder in a normal mode.

43. The method for keying a lock cylinder of claim 22, further comprising the activity of:

releasing a movable stop adapted to resist rotation of said plug body within said cylinder body about said longitudinal axis.

44. The method for keying a lock cylinder of claim 22, further comprising the activity of:

restricting relative movement between said plurality of first plug pin portions and said plurality of second plug pin portions parallel to said longitudinal axis.

45. The method for keying a lock cylinder of claim 22, further comprising the activity of:

learning said first key.

46. The method for keying a lock cylinder of claim 22, further comprising the activity of:

removing said first key from said plug assembly.

47. A system comprising:

a rekeyable lock cylinder coupleable to a door, said rekeyable lock cylinder comprising:

a cylinder body having a longitudinal axis; and

a plug assembly and disposed in said cylinder body, said plug assembly comprising a plug body and a backing rack combinable to cooperatively define a plurality of plug pin chambers, each of said plug pin chambers housing a corresponding plug pin comprising a first plug pin portion releaseably engageable with a second plug pin portion, said backing rack relatively movable with respect to said plug body parallel to said longitudinal axis to allow disengagement of said first plug pin portion from said second plug pin portion; and

a backing rack releasing tool receiving aperture defined by said rekeyable lock cylinder; and

a key adapted to operate said rekeyable lock cylinder.