Patent ID: 8584495

Claim:
An exchangeable cylinder lock that can be mounted removably in a lock housing, comprising: an outer shell having a plug shell defining a cylindrical hole, and a pin chest connected to said plug shell, said pin chest including a first pin hole and a second pin hole, both of which extend along a radial direction of said cylindrical hole; a plug disposed inside said cylindrical hole, and having a third pin hole that can be aligned with said second pin hole; first and second tumbler pins respectively disposed in said second and third pin holes; a cover plate disposed on said pin chest to cover said first and second pin holes, said cover plate having an aperture aligned with said first pin hole; a locking pin disposed in said first pin hole and biased to protrude out of said aperture for engaging the lock housing, said locking pin being depressable to retract for disengaging from the lock housing; and a locking ring disposed around said plug proximate to said first pin hole and rotatable together with said plug, said locking ring having an inner periphery engaging said plug, and an outer periphery capable of abutting against said locking pin, said outer periphery having at least one indentation; wherein, when said plug is rotated using a right key, said locking ring can be moved to a non-blocking position, in which said indentation is aligned with said locking pin to permit depression of said locking pin, or to a blocking position, in which said indentation is moved away from said locking pin to prevent depression of said locking pin.