Rivet gun

Abstract

A rivet gun for setting a self-tapping rivet in one or more work pieces has a tool body having a handle for gripping, a rotation assembly having a motor attached to an axially adjustable shaft and a chuck to thereby impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet. A hydraulic assembly having a pull bushing is connected to a piston rod attached to a piston and a retraction assembly having a mandrel clamp and a mandrel clamp ring is connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip and retract the shank, set the self-tapping rivet in the work pieces and detach the shank from the self-tapping rivet.

1 . A rivet gun for setting a self-tapping rivet having a mandrel with a shank and a self-tapping head, a weakened area of reduced diameter and a hollow rivet body surrounding the mandrel for joining one or more work pieces, the rivet gun comprises:
 a tool body having a handle for gripping;   a rotation assembly having a motor attached to an axially adjustable shaft connected to a chuck to impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet;   a hydraulic assembly;   a retraction assembly adapted to grip the shank of the self-tapping rivet; and   the hydraulic assembly connected to the retraction assembly adapted to retract the shank to set the self-tapping rivet in the work pieces and detach the shank from the self-tapping head at the weakened area of reduced diameter.   
   
   
       2 . The rivet gun of  claim 1  further comprises a braking assembly having a brake disk extending radially outward from a drive shaft connected to the rotation assembly. 
   
   
       3 . The rivet gun of  claim 2  wherein the braking assembly further comprises a brake body with a brake pad biased toward a non-braking position by a brake spring and actuatably urged by a piston against the brake disk to thereby brake rotation of the rotation assembly. 
   
   
       4 . The rivet gun of  claim 1  further comprises a pair of triggers on the handle mechanically or pneumatically interlocked for operating the rivet gun and to prevent simultaneous operation of both triggers. 
   
   
       5 . The rivet gun of  claim 1  wherein the axially adjustable shaft further comprises a drive shaft and a drive shaft coupling having axially extending fingers adapted to mate within and slide relative to similarly shaped groves in the drive shaft. 
   
   
       6 . The rivet gun of  claim 1  wherein the retraction assembly further comprises a mandrel clamp and a mandrel clamp ring circumferentially positioned around the mandrel clamp and connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip the shank. 
   
   
       7 . The rivet gun of  claim 1  wherein the hydraulic assembly further comprises a piston connected to a piston rod attached to a pull bushing and being hydraulically actuated to retract the pull bushing rearward by communicating pressurized hydraulic fluid into a chamber between the piston and a seal body. 
   
   
       8 . The rivet gun of  claim 7  wherein the pull bushing is adapted to retract the mandrel clamp rearward. 
   
   
       9 . The rivet gun of  claim 1  further comprising a mandrel collector attached rearward of the tool body and in communication with a mandrel tube extending through the rotation assembly for collecting detached shanks. 
   
   
       10 . A rivet gun for setting a self-tapping rivet in one or more work pieces, the rivet gun comprises:
 a tool body having a handle for gripping;   a rotation assembly having a motor attached to an axially adjustable shaft and a chuck to thereby impart rotation to the chuck adapted to grip and rotate the shank of the self-tapping rivet;   a hydraulic assembly having a pull bushing connected to a piston rod attached to a piston, and   a retraction assembly having a mandrel clamp and a mandrel clamp ring connected to a spring guide biased toward the mandrel clamp by a spring to thereby compress the mandrel clamp to grip and retract the shank, set the self-tapping rivet in the work pieces and detach the shank from the self-tapping rivet.   
   
   
       11 . The rivet gun of  claim 10  wherein the axially adjustable shaft further comprises a drive shaft and a drive shaft coupling having axially extending fingers adapted to mate within and slide relative to similarly shaped groves in the drive shaft. 
   
   
       12 . The rivet gun of  claim 11  wherein the mandrel clamp is connected to the drive shaft. 
   
   
       13 . The rivet gun of  claim 12  wherein pressurized hydraulic fluid communicated into a chamber between the piston and a seal body causes rearward movement of the piston, the piston rod and the pull bushing which imparts rearward movement to the mandrel clamp. 
   
   
       14 . The rivet gun of  claim 10  wherein the motor is pneumatically or electrically driven. 
   
   
       15 . The rivet gun of  claim 10  wherein the chuck further comprises a plurality of clamp bodies adapted to move from a large cross-section to a smaller cross-section for gripping the shank upon rotation of the chuck and/or rotation assembly. 
   
   
       16 . The rivet gun of  claim 10  wherein the handle has an air input for communicating compressed air into the rivet gun. 
   
   
       17 . A method for setting a self-tapping rivet in one or more work pieces, the method comprising:
 taking a rivet gun having a motor for rotating a chuck;   inserting a shank of the self-tapping rivet into the chuck for gripping the shank;   rotating the chuck with an axially adjustable shaft attached to the motor for creating a hole through the work pieces with a self-tapping head of the self-tapping rivet;   moving a brake body with brake pads into contact with a brake disk attached to the axially adjustable shaft for braking rotation of the axially adjustable shaft;   retracting a piston rearward with a piston rod attached to a pull bushing; and   compressing a mandrel clamp with a mandrel clamp ring to grip the shank for setting the self-tapping rivet in the work pieces and detaching the shank from the self-tapping head.   
   
   
       18 . The method of  claim 17  further comprising the step of urging the mandrel clamp ring forward against the mandrel clamp with a spring guide biased toward the mandrel clamp by a spring. 
   
   
       19 . The method of  claim 17  further comprising the step of communicating pressurized hydraulic fluid into a chamber between a seal body and the piston for driving the piston rearward away from the seal body and imparting rearward movement to the pull bushing for retracting the mandrel clamp. 
   
   
       20 . The method of  claim 17  further comprising the step of sliding axially extending fingers of a drive shaft coupling within and relative to similarly shaped groves in the drive shaft when retracting the mandrel clamp. 
   
   
       21 . A method for setting a self-tapping rivet in one or more work pieces, the method comprising:
 taking a rivet gun having a rotation assembly with a motor for imparting rotation to a chuck, a braking assembly for braking rotation of the rotation assembly and a hydraulic assembly for imparting rearward movement to a retraction assembly;   inserting a shank of the self-tapping rivet into the chuck;   running the motor to rotate the chuck and tap a hole in the work pieces with the self-tapping rivet;   activating the braking assembly by moving a brake body with brake pads into contact with a brake disk of the braking assembly;   engaging the hydraulic assembly to move a piston with a piston rod attached to a pull bushing rearward for imparting rearward movement to the mandrel clamp; and   retracting the mandrel clamp for setting the self-tapping rivet in the work pieces and detaching the shank.   
   
   
       22 . The method of  claim 21  further comprising the step of pressing a first trigger for disengaging the brake assembly and activating the rotation assembly. 
   
   
       23 . The method of  claim 22  further comprising the step of pressing a second trigger for engaging the brake assembly and activating the hydraulic assembly and the retraction assembly. 
   
   
       24 . The method of  claim 23  further comprising the step of mechanically or pneumatically interlocking the first trigger and the second trigger to prevent simultaneous operation of both triggers. 
   
   
       25 . The method of  claim 21  further comprising the step of rotating the chuck one direction for gripping and rotating the shank with a plurality of clamp bodies and an opposite direction for releasing the plurality of clamp bodies from the shank. 
   
   
       26 . The method of  claim 21  further comprising the step of connecting an axially adjustable shaft to the mandrel clamp for retracting the mandrel clamp. 
   
   
       27 . The method of  claim 21  further comprising the step of ejecting detached shanks from the self-tapping rivet from the mandrel clamp through a mandrel tube into a mandrel collector behind the motor.