US Patent 7278338 Control device for ratchet wrench

A ratchet wrench includes a head having an engaging portion for mounting an object and a through hole which includes an engaging inner periphery and a smooth inner periphery, and is closed by a bottom plate with a central hole. A movable member is movably received in the second through hole and includes a driving section and a connection section. An operation portion includes a handle and a mounting portion which has a connection recess so as to be engaged with the connection section of the movable member. The driving section of the movable member is removably engaged with the engaging inner periphery. By moving the movable member relative to the mounting portion, the handle can be selectively rotated freely or co-rotated with the head.