Continuously shooting pneumatic grease gun structure

Abstract

Continuously shooting pneumatic grease gun structure including an air chamber housing defining therein an elongated air chamber. A push hole extends from the air chamber through one end of the housing to outer side thereof. A piston is reciprocally axially movably disposed in the air chamber between a start position and an end position. When in the end position, the piston permits the air in the air chamber to pass through the piston and escape from an outlet passage of the housing. A grease push rod is coaxially fitted in the push hole and synchronously movable along with the piston. A restoring spring is compressed between the end of the housing and the piston to resiliently keep the piston in the start position. A controlling valve is movably disposed on the housing between an open position and a close position. When in the close position, the controlling valve blocks an inlet passage of the housing to hinder external high pressure air from entering the air chamber, while when in the open position, the controlling valve unblocks the inlet passage, permitting external high pressure air to enter the air chamber. A shift air passage is formed in the body section for such conducting the air in the air chamber as to move the controlling valve from the open position to the close the position.

What is claimed is:  
     
         1 . Continuously shooting pneumatic grease gun structure comprising: 
 an air chamber housing including a body section defining therein an elongated air chamber, an inlet passage formed on the body section for communicating one end of the air chamber with outer side of the air chamber housing, an outlet passage formed on the body section for communicating another end of the air chamber with the outer side of the air chamber housing, a push hole extending to outer side of the air chamber housing through a section of the body section corresponding to the other end of the air chamber;    a piston disposed in the air chamber, the piston being reciprocally axially movable within the air chamber between a start position and an end position, whereby when in the end position, the piston permits the air in the air chamber to pass through the piston and escape through the outlet passage to outer side of the air chamber housing;    a grease push rod coaxially fitted in the push hole and synchronously movable along with the piston; and    a restoring spring compressed between the other end of the air chamber and a face of the piston opposite to the other end, the restoring spring serving to provide resilient force to keep the piston in the start position, said pneumatic grease gun structure being characterized in that the pneumatic grease gun structure further comprising: 
 a controlling valve disposed on the body section and movable between an open position and a close position, whereby when in the close position, the controlling valve blocks the inlet passage to hinder external high pressure air from entering the air chamber, while when in the open position, the controlling valve unblocks the inlet passage, permitting external high pressure air to pass through the inlet passage into the air chamber; and  
 a shift air passage formed in the body section for such conducting the air in the air chamber as to move the controlling valve from the open position to the close the position, when the piston is positioned in the start position, the controlling valve being positioned in the open position.  
   
     
     
         2 . Continuously shooting pneumatic grease gun structure as claimed in  claim 1 , wherein the controlling valve has a cylindrical body, an annular inlet groove being formed on a circumference of the cylindrical body, whereby when the controlling valve is positioned in the open position, the inlet groove communicates with the inlet passage.  
     
     
         3 . Continuously shooting pneumatic grease gun structure as claimed in  claim 2 , wherein the air chamber housing is formed with a cavity, the cavity inward extending from a section of the body section corresponding to the end of the air chamber and passing through the inlet passage, the controlling valve being accommodated in the cavity.  
     
     
         4 . Continuously shooting pneumatic grease gun structure as claimed in  claim 1 , wherein an opening of one end of the shift air passage communicates with the air chamber in a position corresponding to the end position of the piston, while the opening of the other end of the shift air passage is formed on a portion of the body section corresponding to the open position of the controlling valve, whereby when the piston is driven by the high pressure air to move from the start position to the end position, the high pressure air flows through the shift air passage to one end of the controlling valve to forcedly move the controlling valve from the open position to the close position.  
     
     
         5 . Continuously shooting pneumatic grease gun structure as claimed in  claim 1 , wherein: 
 the piston has a circular piston body coaxially disposed in the air chamber, a shaft hole extending through the piston body along a curvature center thereof, several escape channels being axially formed on a wall of the shaft hole; and    the grease push rod coaxially passes through the shaft hole and is movable between an escape position and a sealing position, whereby when in the escape position, the openings of the escape channels formed on two faces of the piston respectively communicate with different spaces of the air chamber on two sides of the piston, permitting the entire air chamber to communicate with the outlet passage, while when in the sealing position, the spaces of the air chamber on two sides of the piston are hindered from communicating with each other.    
     
     
         6 . Continuously shooting pneumatic grease gun structure as claimed in  claim 5 , further comprising a restricting spring which provides resilient force to keep the grease push rod in the escape position.  
     
     
         7 . Continuously shooting pneumatic grease gun structure as claimed in  claim 6 , wherein the restricting spring is fitted around the grease push rod between the push hole and the piston, one end of the restricting spring abutting against a projecting abutting section formed on the grease push rod.  
     
     
         8 . Continuously shooting pneumatic grease gun structure as claimed in  claim 5 , wherein the grease push rod has a rod body coaxially fitted in the shaft hole, one end of the rod body extending into the push hole, the grease push rod further having a closing body disposed at the other end of the rod body for sealing the openings of the escape channels.  
     
     
         9 . Continuously shooting pneumatic grease gun structure as claimed in  claim 8 , wherein the restricting spring is fitted around the rod body between the closing body and a face of the piston facing the closing body.