Abstract: A cylinder lock is provided having a sleeve rotatably receivable within the inner core of a sleeve. A cylinder retainer is slidably mounted within a cylinder retainer slot in the cylinder for radial movement therein. The cylinder retainer is movable between a first cylinder retaining position wherein the outer end of the cylinder retainer projects from the cylinder, a second retracted position wherein the outer end of the cylinder retainer is retracted within the cylinder. A slam resistance pad is mounted within the cylinder lock between the cylinder retainer and a stop surface in the sleeve such that if a thief attempts to remove the cylinder from the sleeve, the slam resistance pad is compressed between the cylinder retainer and the stop surface in the sleeve and dissipates the impact force on the cylinder retainer.

Abstract: A mechanical lock is provided which prevents forced rotation of the cylinder when a mated key is not present in the key slot. The lock includes a cylinder rotatably supported within a sleeve. The cylinder defines a longitudinal axis and a keyway disposed along the axis for slidably receiving a key therein. A cylinder head extends circumferentially about a first end of the cylinder and includes a frangible ring portion which fractures in response to a predetermined rotational force. A tab extends from the cylinder head and includes a frangible base which also fragments in response to a predetermined rotational force. The mechanical lock further includes a sidebar for preventing rotation of the cylinder when a mated key is not present therein. The sidebar includes a rib extending therefrom which prevents the longitudinal sliding of the sidebar out of the mechanical lock when the cylinder head has been broken away from the cylinder.