Setting tool for blind rivet

Abstract

A setting tool for a blind rivet, the setting tool including a shell as well as a drive unit, a pull unit, a clamping unit, and a nose part which are contained in the shell, wherein the clamping unit includes a plurality of clamping blocks angularly arrayed around a pulling direction in sequence; a plurality of clamping teeth are provided on an inner side, facing a mandrel of a blind rivet, of each clamping block; the clamping teeth at a front section of the clamping block are at least partially removed in advance to reduce or eliminate a concentrated stress or shear force acting on the front sections of the clamping blocks and generated due to unequal acting forces from the clamping sleeve and the blind rivet, wherein the unequal acting forces are caused by actual processing tolerance, design, or the fact that the mandrel of the blind rivet cannot be totally parallel to the axis R constantly during riveting.

What is claimed is: 
     
         1 - 10 . (canceled) 
     
     
         11 . A setting tool for a blind rivet, the setting tool comprising:
 a shell;   a drive unit;   a pull unit;   a clamping unit; and   a nose part, the drive unit, pull unit, clamping unit and nose part contained in the shell,   the clamping unit including a clamping sleeve connected to the pull unit, a plurality of clamping blocks angularly arrayed around a pulling direction, and a clamping spring;   the clamping sleeve having an enclosing wall and a clamping opening defined by the enclosing wall;   backs of the clamping blocks abutting against an inner wall of the enclosing wall;   the clamping blocks including a plurality of clamping teeth on an inner side, facing a mandrel of a blind rivet, to improve clamping of the clamping blocks to the mandrel of the blind rivet;   the clamping spring configured such that the clamping blocks are movable in the clamping sleeve between an initial position and a final position; when the clamping block is located at the final position, a front section of the clamping block protruding from the clamping opening, and a rear section of the clamping block being retained in the clamping sleeve; and   the clamping teeth located at the front section of the clamping block are at least partially removed in advance.   
     
     
         12 . The setting tool as recited in  claim 11  wherein the clamping teeth at the front section of the clamping block are all removed. 
     
     
         13 . The setting tool as recited in  claim 11  wherein the clamping teeth at the front section of the clamping block are partially removed and are lower than the clamping teeth at the rear section of the clamping block. 
     
     
         14 . The setting tool as recited in  claim 11  wherein, when the clamping blocks are located at the final position, the clamping teeth, closest to the clamping opening, at the front sections of the clamping blocks are all or at least partially removed. 
     
     
         15 . The setting tool as recited in  claim 11  wherein the clamping teeth are formed as convex ribs uniformly arrayed on the clamping block in the pulling direction; the convex rib including a top edge, a first side surface, and a second side surface, wherein the top edge is perpendicular to a central line of the mandrel; the first side surface faces the drive unit and extends from the top edge to a root of the corresponding clamping tooth at a first angle to the pulling direction; and the second side surface faces the nose part and extends from the top edge to the root of the clamping tooth at a second angle to the pulling direction. 
     
     
         16 . The setting tool as recited in  claim 15  wherein a rounded corner with a smooth transition portion is formed at the root of the clamping teeth by the first side surface and the second side surface. 
     
     
         17 . The setting tool as recited in  claim 15  wherein the first angle is larger than the second angle. 
     
     
         18 . The setting tool as recited in  claim 15  wherein the top edge of the clamping tooth at the rear section of the clamping block is at least partially in surface-to-surface contact with a peripheral surface of the mandrel. 
     
     
         19 . The setting tool as recited in  claim 15  wherein the clamping blocks are made from medium-carbon nickel-chromium-molybdenum alloy steel with a nickel content of about 1.6%-2.0%. 
     
     
         20 . The setting tool as recited in  claim 19  wherein, after the clamping blocks are subjected to heat treatment, the depth of a hardened layer ranges from 0.5 mm to 0.8 mm, and the surface hardness is not less than HV680. 
     
     
         21 . A setting tool for a blind rivet, the setting tool comprising:
 a shell;   a drive unit;   a pull unit;   a clamping unit; and   a nose part, the drive unit, pull unit, clamping unit and nose part contained in the shell,   the clamping unit including a clamping sleeve connected to the pull unit, a plurality of clamping blocks angularly arrayed around a pulling direction, and a clamping spring;   the clamping sleeve having an enclosing wall and a clamping opening defined by the enclosing wall;   backs of the clamping blocks abutting against an inner wall of the enclosing wall;   the clamping blocks including a plurality of clamping teeth on an inner side, facing a mandrel of a blind rivet, to improve clamping of the clamping blocks to the mandrel of the blind rivet;   the clamping spring configured such that the clamping blocks are movable in the clamping sleeve between an initial position and a final position; when the clamping block is located at the final position, a front section of the clamping block protruding from the clamping opening, and a rear section of the clamping block being retained in the clamping sleeve; and   the front section of the clamping block being at least partially free of the clamping teeth or being lower than the clamping teeth at the rear section of the clamping block.   
     
     
         22 . The setting tool as recited in  claim 21  wherein the front section of the clamping block is completely free of the clamping teeth. 
     
     
         23 . The setting tool as recited in  claim 21  wherein the clamping teeth at the front section of the clamping block are lower than the clamping teeth at the rear section of the clamping block. 
     
     
         24 . The setting tool as recited in  claim 21  wherein, when the clamping blocks are located at the final position, the clamping teeth, closest to the clamping opening, at the front sections of the clamping blocks are all or at least partially absent. 
     
     
         25 . The setting tool as recited in  claim 21  wherein the clamping teeth are formed as convex ribs uniformly arrayed on the clamping block in the pulling direction; the convex rib including a top edge, a first side surface, and a second side surface, wherein the top edge is perpendicular to a central line of the mandrel; the first side surface faces the drive unit and extends from the top edge to a root of the corresponding clamping tooth at a first angle to the pulling direction; and the second side surface faces the nose part and extends from the top edge to the root of the clamping tooth at a second angle to the pulling direction. 
     
     
         26 . The setting tool as recited in  claim 25  wherein a rounded corner with a smooth transition portion is formed at the root of the clamping teeth by the first side surface and the second side surface. 
     
     
         27 . The setting tool as recited in  claim 25  wherein the first angle is larger than the second angle. 
     
     
         28 . The setting tool as recited in  claim 25  wherein the top edge of the clamping tooth at the rear section of the clamping block is at least partially in surface-to-surface contact with a peripheral surface of the mandrel. 
     
     
         29 . The setting tool as recited in  claim 25  wherein the clamping blocks are made from medium-carbon nickel-chromium-molybdenum alloy steel with a nickel content of about 1.6%-2.0%. 
     
     
         30 . The setting tool as recited in  claim 29  wherein, after the clamping blocks are subjected to heat treatment, the depth of a hardened layer ranges from 0.5 mm to 0.8 mm, and the surface hardness is not less than HV680.