Pneumatic tool having clockwise and counterclockwise rotation function

Abstract

A pneumatic tool includes a housing, an air cylinder disposed in the housing, a valve unit, and a controlling unit. The air cylinder has an outer surface formed with a valve seat. A rotary valve of the valve unit is rotatable to allow compressed air to flow into the air cylinder through a selected one of first and second passages to thereby produce clockwise or counterclockwise rotation of the tool. The controlling unit includes a movable pin operable to move in the housing to drive rotation of the rotary valve. Preferably, the valve unit is disposed on the housing in a manner that the space occupied thereby in the housing is reduced.

I claim: 
     
         1 . A pneumatic tool comprising:
 a housing having an intake passage adapted to be connected with a compressed air source;   an air cylinder disposed in said housing and including a cylinder wall centered at an X-axis and defining an air chamber, a valve seat centered at a Z-axis perpendicular to said X-axis and connected to said cylinder wall, a first passage, and a second passage, said first and second passages being formed in said cylinder wall and being in fluid communication with said air chamber and said valve seat;   a valve unit including a rotary valve that is disposed in said valve seat and that has an intermediate passage, said rotary valve being rotatable about said Z-axis between a first position whereat said intermediate passage is in fluid communication with said first passage in said air cylinder, and a second position whereat said intermediate passage is in fluid communication with said second passage in said air cylinder; and   a controlling unit including a movable pin disposed movably on said housing and operable to move in said housing along a Y-axis perpendicular to said X-axis and said Z-axis to thereby drive rotation of said rotary valve.   
     
     
         2 . The pneumatic tool as claimed in  claim 1 , wherein said valve unit further includes an air-guiding retainer disposed removably on said valve seat so as to confine said rotary valve in said valve seat. 
     
     
         3 . The pneumatic tool as claimed in  claim 2 , wherein said valve unit further includes an air-guiding tube connected to said air-guiding retainer and in fluid communication with said air-guiding retainer and said intake passage in said housing. 
     
     
         4 . The pneumatic tool as claimed in  claim 1 , wherein said valve seat has a first opening formed at a side thereof, and said rotary valve further has a plurality of teeth formed on an outer surface thereof and exposed in said first opening in said valve seat, said controlling unit further including a pushing member engaging said teeth of said rotary valve and connected to said movable pin. 
     
     
         5 . The pneumatic tool as claimed in  claim 4 , wherein said pushing member is disposed between said rotary valve and said movable pin along said X-axis, and is formed at an end thereof with a rack engaging said teeth of said rotary valve, and formed at an opposite end thereof with an engaging portion that is connected to said movable pin. 
     
     
         6 . The pneumatic tool as claimed in  claim 5 , wherein said air cylinder further includes a projection formed on said cylinder wall and adjacent to said seat valve, said projection obstructing said pushing member so as to maintain engagement between said rack and said teeth. 
     
     
         7 . The pneumatic tool as claimed in  claim 5 , wherein said controlling unit further includes a positioning member, said movable pin having a hole formed therethrough, said positioning member having an engaging portion and an intermediate portion extending through said hole in said movable pin, one of said engaging portions of said positioning member and said pushing member being inserted fittingly into the other of said engaging portions of said positioning member and said pushing member. 
     
     
         8 . The pneumatic tool as claimed in  claim 7 , wherein said housing further has a front seat and a rear seat connected to said front seat along said X-axis, said rear seat including a housing body for receiving said air cylinder, said valve unit, and said controlling unit, and a handle connected to said housing body and formed with said intake passage, said controlling unit further including a resilient member disposed between said positioning member and said front seat for biasing said engaging portion of said positioning member to engage said engaging portion of said pushing member. 
     
     
         9 . The pneumatic tool as claimed in  claim 8 , wherein said rear seat further includes an exhaust passage, said valve seat further having a second opening formed at an opposite side thereof and in fluid communication with said exhaust passage, said rotary valve further having a notch in fluid communication with said second opening, said notch being in fluid communication with said second passage in said air cylinder when said rotary valve is at said first position, and with said first passage in said air cylinder when said rotary valve is at said second position.