Electric blind rivet setting device

Abstract

The present invention provides a small electric blind rivet setting device that is capable of being driven by a battery and that does not require a pathway for recovering the broken mandrels to be provided in the motor shaft. A recovery container 10 is provided in a tool housing 27 forward of an electric motor 13 in the axial direction, and a spindle 14, which rotates because of the rotation of a drive shaft 18 connected to the electric motor circumventing the recovery container, is connected so as to move a pulling head ( 30 ) in the axial direction. The positive rotation, stopping of rotation and reverse rotation of the electric motor are controlled by a pulling operation on a trigger and detecting the position of the pulling head in the axial direction.

What is claimed is: 
     
       1. An electric blind rivet setting device comprising
 a hollow nose that accepts a mandrel of a blind rivet comprising a mandrel and rivet body, a tool housing disposed in the axial direction behind said nose, jaws that are disposed inside said nose for gripping the mandrel, a pulling head that is inside said nose for pulling said jaws backward in the axial direction from a home position and returns said jaws to said home position, an electric motor that forms a drive power source for moving said pulling head in the axial direction and a drive force transfer gear train to pull said pulling head from said home position backward in the axial direction and return said pulling head forward in the axial direction to said home position from a back position by the rotation of said electric motor;   said housing including a handle and a trigger switch for operating said electric motor to set the rivet when the rivet body is expanded by the mandrel of a blind rivet gripped in said jaws being pulled backward in the axial direction from said home position by said pulling head,   said housing including a recovery container for receiving a part of the broken mandrel shaft from said pulling head when said rivet body is set in members being riveted, said container being located in said housing between said motor and said pulling head on a front side of said electric motor in the axial direction,   said electric motor being at the back end of said tool housing and disposed on a rear side in the axial direction of said recovery container, said drive force transfer gear train being provided in a part of said tool housing below said recovery container, circumventing said recovery container, said drive force transfer gear train being connected to said electric motor on the rear side of said recovery container so that said drive force transfer gear train rotates with said electric motor, said gear train including a drive shaft that extends forward in the axial direction from a back end and is mounted for rotation about its own axis, and a spindle that is connected to an end part of said drive shaft at the front side of said recovery container so that said spindle is rotated by the rotation of said drive shaft, said spindle being connected to said pulling head so that said pulling head is moved backward in the axial direction or forward in the axial direction by the rotation of said spindle and   a control circuit including said trigger switch and two position sensors for controlling said electric motor forward rotation, stopping of rotation and reverse rotation by detecting pulling operations of said trigger and the position of said pulling head in the axial direction due to the rotation of said drive shaft.   
     
     
       2. The setting device according to  claim 1  wherein
 said drive shaft is disposed so as to be able to rotate around its own axis in the space below said recovery container by a rear gear coupled to a motor gear connected to said electric motor, said drive shaft also being coupled to a front gear that is mated to a spindle gear connected to said spindle, said drive shaft having external threads formed in the outer circumferential surface of said drive shaft between said rear gear and said front gear, 
 said drive shaft having a first collar and a second collar, said collars having internal threads coupled to said drive shaft threads to move the collars in the axial direction upon rotation of said drive shaft, a first one of said sensors being positioned in said tool housing adjacent to said first collar and a second one of said sensors positioned in said tool housing adjacent to said second collar, a control circuit that receives a signal from said first sensor, a signal from said second sensor and a signal from the pulling operation of said trigger, said control circuit operating so that, when said pulling head is in the state of being in said home position, said electric motor is rotated positively to move the pulling head to the rear in the axial direction when the operation of pulling said trigger is carried out and when said pulling head has been pulled back to the back position in the axial direction, the rotation of said electric motor is stopped and with the release of said trigger pulling operation, said electric motor reverses rotation and said pulling head is returned to said home position. 
 
     
     
       3. The setting device according to  claim 2 , wherein said first sensor is a first microswitch that is turned on and off by the movement of said first collar on said drive shaft in the axial direction, and said second sensor is a second microswitch that is turned on and off by the movement of said second collar on said drive shaft in the axial direction. 
     
     
       4. The setting device according to  claim 3 , wherein, when said pulling head is in the home position, an off signal is sent to the control circuit from said trigger switch as long as the trigger is not pulled, said first collar energizes said first microswitch and an on signal is sent to the control circuit by said first microswitch, an off signal is sent to the control circuit by the second microswitch as long as the second microswitch is not energized by said second collar, and said control circuit maintains the pulling head in the home position,
 in the home position, said control circuit rotates said electric motor positively when said trigger is operated by pulling and an on signal is sent to the control circuit by said trigger, said drive shaft is rotated, said spindle is rotated, said pulling head pulls a mandrel of a blind rivet gripped in said jaws a prescribed length rearward in the axial direction and breaks the mandrel shaft part gripped in said jaws along with setting the blind rivet in members being riveted, said first collar also moves a prescribed length in said first direction because of the rotation of said drive shaft and separates from the position that energizes said first microswitch, the positive rotation of said electric motor is stopped by an off signal sent by said first microswitch, and an on signal output by said second microswitch when said second collar moves a prescribed length in said first direction to a position that energizes said second microswitch and an on signal is sent from said trigger switch,   when the pulling operation of said trigger switch is released after stopping the positive rotation of said electric motor, an off signal is received from said trigger switch, an off signal is received from said first microswitch and an on signal is received from said second microswitch, and said electric motor is rotated in reverse, said drive shaft is rotated, said spindle is rotated in reverse, said pulling head is returned forward in the axial direction and returns to said home position with said jaws, said first collar also moves a prescribed length in a second direction opposite to said first direction because of the rotation of said drive shaft and returns to the position that energizes said first microswitch, an on signal is sent by said first microswitch, said second collar moves a prescribed length in said second direction and separates from the position that energizes said second microswitch, an off signal is sent by said second microswitch and said home position state is maintained by the off signal from said trigger switch, the on signal from said first microswitch and the off signal from said second microswitch.   
     
     
       5. A blind rivet setting tool comprising
 an elongated housing having an axis and a handle;   said housing having a nosepiece aligned with said axis containing a receptacle for receiving a blind rivet that is to be set;   a pulling head having pulling jaws for gripping the mandrel of a rivet and pulling the mandrel in the direction of the axis to set the rivet;   a mandrel container for receiving broken mandrels, said container being located at a discharge end of the pulling head;   an electric motor located in said housing at an opposite end of said tool from said nosepiece, said motor having a rotary output shaft, said shaft driving a power transfer mechanism comprising a rotary gear on said shaft, a drive shaft parallel to the axis of the housing, said shaft being coupled to rotate with said gear, a pair of collars coupled to said shaft by threads on the shaft and the collars so that the collars move axially of the tool as the shaft rotates, said collars being coupled to said pulling head to grip and pull the mandrel and set the rivet;   a control circuit mounted in said tool for controlling the operation of the tool, said circuit comprising a trigger switch controlled by the operator and a pair of position-sensitive switches positioned adjacent said collars to locate the position of the pulling head and continue a setting operation or return the mechanism to a home position.   
     
     
       6. An electric blind rivet setting device comprising a hollow nose that accepts a mandrel of a blind rivet comprising a mandrel and rivet body, a tool housing disposed in an axial direction behind said nose, jaws disposed inside said nose for gripping the mandrel, a pulling head inside said nose for pulling said jaws backward in the axial direction from a home position and returns said jaws to said home position, an electric motor disposed in the housing for moving said pulling head in the axial direction and a drive force transfer gear train to pull said pulling head from said home position backward in the axial direction and return it forward in the axial direction to said home position by the rotation of said electric motor; said housing including a handle and a trigger switch for operating said electric motor to set the rivet when the rivet body is expanded by the mandrel of a blind rivet gripped in said jaws being pulled backward in the axial direction from said home position by said pulling head, said housing including a recovery container for receiving a part of the broken mandrel shaft from said pulling head, said container being located in said housing between said motor and said pulling head, said drive force transfer gear train being provided in said tool housing, circumventing said recovery container.  
     
     
       7. The electric blind rivet setting tool device of claim 6, wherein said drive force gear train which includes a drive shaft that extends forward in the axial direction from a back side of said recovery container and is mounted for rotation about its own axis, and a spindle that is connected to the end part of said drive shaft at a front side of said recovery container so that said spindle is rotated by the rotation of said drive shaft, said spindle being connected to said pulling head so that said pulling head is moved backward in the axial direction or forward in the axial direction by the rotation of said spindle.  
     
     
       8. The electric blind rivet setting tool device of claim 7, wherein said drive force transfer gear train is connected to said electric motor on the rear side of said recovery container so that it rotates with said electric motor.  
     
     
       9. The electric blind rivet setting tool device of claim 6, further including a control circuit including a position sensor and said trigger switch for controlling said electric motor forward rotation, stopping of rotation and reverse rotation by detecting pulling operations of said trigger and the position of said pulling head in the axial direction due to the rotation of said drive shaft.  
     
     
       10. An electric blind rivet setting device comprising a hollow nose that accepts a mandrel of a blind rivet comprising a mandrel and rivet body, a tool housing disposed in an axial direction behind said nose, jaws disposed inside said nose for gripping the mandrel, a pulling head inside said nose for pulling said jaws backward in the axial direction from a home position and returns said jaws to said home position, an electric motor disposed in the housing for moving said pulling head in the axial direction and a drive force transfer gear train to pull said pulling head from said home position backward in the axial direction and return it forward in the axial direction to said home position by the rotation of said electric motor; said housing including a handle and a trigger switch for operating said electric motor to set the rivet when the rivet body is expanded by the mandrel of a blind rivet gripped in said jaws being pulled backward in the axial direction from said home position by said pulling head, said housing including a recovery container for receiving a part of the broken mandrel shaft from said pulling head, said container being located in said housing between said motor and said pulling head.