Patent ID: 6151994
Filing Date: 2000-11-28
Classification: B25B

Abstract:
A ratchet screwdriver comprising:a plurality of tool bits, each having an intermediate shank portion with a non-circular cross-section, and two bit portions at opposite ends of said shank portion and being designed to have different configurations for driving different types of workpieces;an elongated handle having front and rear parts opposite to each other in an axial direction and a juncture therebetween which define a juncture line radial to said axial direction, said front and rear parts cooperating with each other to define a ratchet shaft receiving hole therethrough;a drive shaft including a cylindrical shaft portion with two opposite ends, each of which is formed with an axially extending bit engaging hole of a non-circular cross-section to receive said intermediate shank portion of a respective one of said tool bits so as to expose said bit portion of said respective one of said tool bits outwardly of said bit engaging hole; anda ratchet assembly includinga cylindrical ratchet shaft disposed rotatably in said ratchet shaft receiving hole, and having a circumferential wall with opposite first and second end portions to permit extension of said drive shaft, thereby exposing said bit engaging hole of said drive shaft outwardly of said handle when said drive shaft is removably inserted into said circumferential wall via said first end portion, and a ratchet wheel mounted securely and integrally thereon between said first and second end portions;engaging means interposed between said ratchet shaft and said drive shaft for preventing axial displacement relative to each other and permitting co-rotation together;a ratchet housing including a coupling portion with a first outer circumferential wall of non-circular cross-section and sleeved on said ratchet shaft and coupled with at least one of said front and rear parts so as to be co-rotatable axially therewith, a wheel confining portion extending from said coupling portion and defining a cavity enclosing said ratchet wheel therein, and a mounting shoulder between said coupling portion and said wheel confining portion and abutting against a front side of said ratchet wheel, said wheel confining portion further being formed with an axially extending pawl retaining groove in communication with said cavity,a pawl member disposed in said pawl retention groove, and having a pivot portion pivotally mounted on said mounting shoulder and an engaging portion extending integrally and radially from said pivot portion into said cavity, anda biasing member biasing said pawl member and urging said engaging portion to mesh constantly with said ratchet wheel such that when said handle is driven in a counterclockwise direction, said ratchet shaft and said drive shaft correspondingly rotate in said counterclockwise direction,whereby, when said handle has been turned around said juncture line by 180 degrees to have the positions of said front and rear parts reversed, and said drive shaft is removed from said first end portion and subsequently inserted into said second end portion of said ratchet shaft, rotation of said handle in a clockwise direction will reverse the drive direction of said drive shaft.