Patent ID: 8146395

Claim:
An anti-theft lock comprising a lock ( 1 ), a lock core ( 2 ) and a lock cover ( 9 ), and characterized in that the lock ( 1 ) includes two axial grooves ( 18 ) which are disposed at diametrically opposite locations on an inner wall of the lock ( 1 ) and an annular groove ( 10 ) which has a rectangular cross section and is provided on the inner wall of the lock ( 1 ) adjacent an end proximal to a key slot; the lock core ( 2 ) includes multiple rectangular tumbler holes ( 19 ) divided by baffles ( 6 ), each tumbler hole ( 19 ) has a spring hole ( 22 ) defined in one end of the tumbler hole ( 19 ), a round controlling plate ( 8 ), of which the diameter is the same as that of the core ( 2 ), is disposed between the lock cover ( 9 ) and the lock core ( 2 ), a key slot ( 15 ) is provided in the round controlling plate ( 8 ) and two V-shaped grooves ( 16 ) are provided in an inner sidewall of the round controlling plate ( 8 ) and correspond to two ends of the key slot ( 15 ); the lock core ( 20 ) has two swallowtail grooves ( 20 ) which are disposed at diametrically opposite locations on an outer wall of the lock core ( 20 ), a brake shaft ( 4 ) is mounted slidably in one of the swallowtail grooves ( 20 ), the brake shaft ( 4 ) has an inner end abutting with a spring ( 3 ), an outer end provided with a boss ( 13 ) corresponding to one of the V-shaped grooves ( 16 ) in the round controlling plate ( 8 ), a brake block ( 7 ) provided on a curved wall of the brake shaft ( 4 ) adjacent to the outer end and corresponding to one of the axial grooves ( 18 ) and the annular groove ( 10 ) and multiple brake position teeth ( 14 ) provided symmetrically on two inner walls of the brake shaft ( 4 ), wherein each adjacent brake position teeth ( 14 ) has a distance from each other equal to a thickness of a plate tumbler ( 5 ); the round controlling plate ( 8 ) has a side corresponding to an inner end of the lock cover ( 9 ) and an outer edge corresponding to an inner wall of the lock ( 1 ); the plate tumbler ( 5 ) has a rectangular hole ( 24 ) corresponding to a key slot ( 21 ) in the lock core, a pressing bar ( 12 ) provided on one side of the plate tumbler ( 5 ) and abutting with a spring ( 23 ) mounted in one of the spring holes ( 22 ) and multiple tooth grooves ( 17 ) provided on two outer sides of two ends of the plate tumbler ( 5 ) and corresponding to the brake position teeth ( 14 ); the key slot ( 21 ) in the lock core ( 2 ) has a width wider than that of the key slot ( 15 ) in the round controlling plate ( 8 ).