Barrel assembly for a rivet gun

Abstract

A barrel assembly for a rivet gun has a tube body, a vising piston and a rear valve. The tube body has an assembling hole and a bypass hole. The vising piston is mounted slidably in the assembling hole of the tube body and has a piston head mounted slidably in the assembling hole of the tube body and having two O-rings mounted around the piston head at an interval, and a shaft formed on the piston head. The rear valve mounted on the rear opening of the assembling hole of the tube body. When the vi sing piston moves backward adjacent to the rear opening of the assembling hole of the tube body, the bypass hole of the tube body is located at the interval between the O-rings and is sealed by the 0-rings without consuming high pressure air from a pneumatic cylinder.

What is claimed is: 
     
         1 . A barrel assembly for a rivet gun comprising:
 tube body having
 an assembling hole defined longitudinally through the tube body and h a front opening and a rear opening; and 
 a bypass hole defined transversely through the tube body and communicating with the assembling hole; 
   a vising piston mounted slidably in the assembling hole of the tube body and having
 a piston head mounted slidably in the assembling hole of the tube body, hermitically contacting an inner surface of the assembling hole and having two O-rings mounted around the piston head at an interval and hermetically contacting the inner surface of the assembling hole; and 
 a shaft formed on and protruding longitudinally from a front end of the piston head; 
   a rear valve mounted on the rear opening of the assembling hole of the tube body;   wherein when the vising piston moves backward adjacent to the rear opening of the assembling hole of the tube body, the bypass hole of the tube body is located at the interval between the O-rings and is sealed by the  0 -rings without communicating with the front opening or the rear opening of the tube body.   
     
     
         2 . The barrel assembly as claimed in  claim 1 , wherein a spring is mounted in the assembling hole of the tube body and has a front end pressing against the piston head and a rear end pressing against the rear valve. 
     
     
         3 . The barrel assembly as claimed in  claim 2 , wherein a tool head is mounted on the front opening of the assembling hole of the tube body and has a vise assembly mounted in the tool head and connected to the vising piston. 
     
     
         4 . The barrel assembly as claimed in  claim 3 , wherein a connecting tube is mounted securely on a rear end of the piston head. 
     
     
         5 . The barrel assembly as claimed in  claim 4 , wherein
 the vising piston further has a through hole defined longitudinally through the piston head and the shaft; and   the connecting tube has a central hole defined longitudinally through the connecting tube and communicating with the through hole of the vising piston.