Power hand tool having power transmission clutch

Abstract

A power hand tool includes a housing for holding a motor therein, a transmission gear set coupled to an output shaft of the motor, a first power transmission member coupled to an output gear of the transmission gear set, a second power transmission member which is rotatably mounted in the housing and coupled to the first power transmission member for synchronous rotation when it is axially inwardly pressed, and a spring member for pushing the second power transmission member away from the first power transmission member for enabling the first power transmission member to run idle.

1 . A power hand tool comprising: 
 a housing;    a motor fixedly mounted inside said housing, said motor having an output shaft;    a transmission gear set mounted inside said housing, said transmission gear set having an input gear fixedly mounted on the output shaft of said motor, and an output gear rotatable by said input gear directly or indirectly;    a first power transmission member coupled to said output gear for rotation with said output gear, said first power transmission member having a coupling hole;    a second power transmission member rotatably mounted inside said housing and axially movable in said housing between a first position and a second position, said second power transmission member having a coupling portion disposed at a first end thereof and a coupling hole disposed at a second end thereof outside said housing for receiving a tool bit, said coupling portion of said second power transmission member being engaged into the coupling hole of said first power transmission member for allowing rotation of said second power transmission member with said first power transmission member when said second power transmission member is moved to said second position, said coupling portion of said second power transmission member being disengaged from the coupling hole of said first power transmission member for allowing said first transmission member to run idle during operation of said motor when said second power transmission member is moved to said first position; and    a spring member mounted in the coupling hole of said first power transmission member and stopped against said second power transmission member to support said second power transmission member in said first position.    
   
   
       2 . The power hand tool as claimed in  claim 1 , further comprising two shaft sleeves respectively sleeved onto said first power transmission member and said second power transmission member and fixedly mounted inside said housing.  
   
   
       3 . The power hand tool as claimed in  claim 1 , wherein the coupling hole of said first power transmission member is a hexagonal hole, and the coupling portion of said second power transmission member has a shape fitting the hexagonal coupling hole of said first power transmission member.