Patent ID: 6578396
Filing Date: 2003-06-17
Classification: E05B,Y10T

Abstract:
A lock, comprising:a shell having tumbler pins and a substantially cylindrical borehole; a substantially cylindrical core plug received coaxially within said borehole of said shell, said core plug being rotatable in said shell and having tumbler pins which engage tumbler pins of said shell, said core plug further having a keyway; a shell housing for removably receiving said shell and said core plug, said housing having a slot; and a retainer ring which secures said core plug and said shell within said housing, said retainer ring comprising a lug and a sleeve formed integral with each other, said sleeve coaxially engaging said core plug, said lug securing said core plug and shell axially within said housing by engaging said slot, said lug being moveable into and out of engagement with said slot by rotation of said sleeve; an upper control pin engageable with said retainer ring to selectively prevent rotation of said retainer ring relative to said shell when said upper control pin is in a first position; an intermediate control pin engageable with said upper control pin to selectively move said upper control pin between said first position and a second position in which said retainer ring is rotatable relative to said shell, said intermediate control pin including a positioning groove cooperating with a positioning lug formed in said retainer ring, such that when said intermediate control pin is in a first position, said intermediate control pin is prevented by virtue of said positioning lug abutting against an end of said positioning groove from entering said keyway when said core plug is rotated relative to said shell during normal lock operation; a lower control pin engageable with a control key inserted into said keyway and with said intermediate control pin, such that when said control key is inserted into said keyway, said lower control pin moves said intermediate control pin to a second position; wherein the insertion and rotation of said control key in said keyway of said core plug moves said lower control pin to thereby move said retainer ring between a secure position in which said retainer lug engages said housing slot, and an install position in which said retainer lug is retracted from said housing slot thereby enabling said shell and core plug to be removed from said housing.