US Patent 7100407 Handled lock set for a door

A lock set includes a hollow intermediate spindle connected to a door latch and to an inner handle assembly, a turning rod extending inside the intermediate spindle, a coupler connected to a key-operated lock of an outer handle assembly so as to be turned thereby and connected to the turning rod so as to actuate the turning rod, a first clutch plate fitted around the turning rod for rotation together with the turning rod, and a second clutch plate movably disposed around the turning rod for sliding away from or toward the first clutch plate. In a preferred embodiment, the coupler has a hole to receive a tail end of the key-operated lock. The tail end is rotatable limitedly within the hole of the coupler.