US Patent 7762161 Ratchet screwdriver

A ratchet screwdriver includes a handle having a hole co-axially defined in the handle. A ratchet mechanism is co-axially received in the hole in the handle and comprises a ratchet wheel for driving the ratchet screwdriver with bi-directional operating and a selector for selectively determining the operational direction of the ratchet wheel. A driving shaft is relatively and co-axially mounted in the ratchet mechanism and ratchetly and bi-directionally driven by the ratchet wheel.