Patent ID: 6857297

Claim:
A lock for locking a door panel to a door frame, comprising: a knob assembly comprising a front protective housing and a rear knob frame adapted for being mounting on a front and a rear side of said door panel respectively so as to define a lock cavity between said front protective housing and said second knob frame; a door latch assembly comprising a latch actuation member transversely disposed within said lock cavity and a locking latch connected to said latch actuation member in a slidably movable manner; an actuation unit mounted to said knob assembly to actuate said locking latch to slidably move between a locked position and an unlocked position, wherein in said locked position, said locking latch is received in said lock cavity for allowing a pivotal movement of said door panel with respect to said door frame, wherein in said unlocked position, said locking latch is slidably and outwardly extended for engaging with said door frame so as to lock up with said door frame; and a lock enhancing device, which comprises: a reinforcing member for substantially mounting to said door panel between said front and said rear side thereof; and a latch guider integrally extended from said reinforcing member within said lock cavity to couple with an inner end portion of said latch actuation member so as to substantially retain said latch actuation member within said lock cavity in position, wherein said latch guider is engaged between said first protective housing and said second knob frame so as to block a rotational movement of each of said first protective housing and said second knob frame with respect to said actuation unit, wherein said latch guider of said lock enhancing device has a coupling slot, having a predetermined length, longitudinally formed on an inner side thereof wherein an inner end portion of said latch actuation member is movably coupled with said coupling slot in such a manner that a movement of said latch actuation member is substantially restricted by two ends of said coupling slot, so that said latch actuation member is retained in position in said lock cavity determined by a longitudinal length of said coupling slot, wherein said latch guider of said lock enhancing device has an inner surface of rectangular cross section, an outer convexly curved surface, and two side flat surfaces to define a semicircular cross sectional shape of said latch guider, wherein a radius of curvature of a said curved outer surface is substantially equal to that of a side boundary of the lock cavity, so that said latch guider is capable of being fittedly and securely engaged with the door panel.