Fastener and its setting method

Abstract

A fastener comprises a flange having an insertion hole, a plurality of circumferentially spaced clamping legs extending from the flange, and a nut connected integrally to ends of the clamping legs. The nut and the clamping legs are inserted into a mounting hole of a workpiece. Then the nut is pulled toward the flange to cause buckling of the clamping legs. The fastener is set to the workpiece by clamping the workpiece between the buckled clamping legs and the flange. Each of the clamping legs has a buckling portion, a nut-side leg portion and a flange-side leg portion. The buckling portion is thinner than the nut-side and flange-side leg portions. The nut-side leg portion has a higher strength than the flange-side leg portion. A region of the nut-side leg portion adjacent to the nut has a lower strength than that of the remaining region thereof.

What is claimed is:  
     
         1 . A fastener comprising: 
 a flange having an insertion hole for receiving a bolt therethrough, and a portion outside the insertion hole to be brought into juxtaposition with a workpiece;    a plurality of clamping legs extending from a region of the flange outside the insertion hole and being circumferentially spaced apart from each other; and    a nut connected integrally to ends of the clamping legs,    wherein the nut and the clamping legs are inserted into a mounting hole of the workpiece, and then the nut is pulled toward the flange to cause buckling of the clamping legs in such a manner that a buckling portion in each of the clamping legs at an intermediate region thereof is expanded radially outward to allow the fastener to be set to the workpiece by clamping the workpiece between the buckled clamping legs and the flange,    wherein the buckling portion in each of the clamping legs is thinner than the remaining portion of the clamping leg to allow a buckling beginning point to be located thereat, the remaining portion including a nut-side leg portion extending from the buckling portion to the nut, and a flange-side leg portion extending from the buckling portion to the flange; and    wherein the nut-side leg portion is relatively thick so as to have a higher strength than that of the flange-side leg portion, and a region of the nut-side leg portion adjacent to the nut is relatively thin so as to have a lower strength than the remaining region thereof.    
     
     
         2 . The fastener as defined in  Claim 1 , wherein the flange has a shape with at least two parallel linear sides in plan view, the shape being selected from a group including a quadrangle, a hexagon, and a pseudo-ellipse formed by cutting a circle shape with two parallel straight lines.  
     
     
         3 . A fastener comprising: 
 a flange having an insertion hole for receiving a bolt therethrough, and a portion outside the insertion hole and adapted to be brought into juxtaposition with a workpiece;    a plurality of clamping legs extending from a region of the flange outside the insertion hole and being circumferentially spaced apart from each other; and    a nut connected integrally to ends of the clamping legs,    wherein the nut and the clamping legs are inserted into a mounting hole of the workpiece, and then the nut is pulled toward the flange to cause buckling of the clamping legs in such a manner that a buckling portion in each of the clamping legs at an intermediate region thereof is expanded radially outward to allow the fastener to be set to the workpiece by clamping the workpiece between the buckled clamping legs and the flange, and    wherein the flange has a shape with at least two parallel linear sides in plan view, the shape being selected from a group including a quadrangle, a hexagon, and a pseudo-ellipse formed by cutting a circle shape with two parallel straight lines.    
     
     
         4 . A method for setting the fastener as defined in Claim  2  to a workpiece, comprising the steps of: 
 inserting a bolt through the insertion hole of the flange of the fastener to threadedly engage the bolt with the nut, and inserting the nut and the clamping legs of the fastener with the bolt into a mounting hole of the workpiece to bring the flange into juxtaposition with the workpiece;  
 engaging either a general-purpose tool or a portion of the workpiece with the at least two linear sides of the flange to prevent the fastener from being rotated upon the rotation of the bolt; and  
 rotating the bolt relative to the fastener to further screw the bolt into the nut so as to pull the nut toward the flange to cause buckling of the clamping legs in such a manner that the buckling portion in each of the clamping legs is expanded radially outward to allow the fastener to be set to the workpiece by clamping the workpiece between the buckled clamping legs and the flange.  
 
     
     
         5 . A method for setting the fastener as defined in  Claim 3  to a workpiece, comprising the steps of: 
 inserting a bolt through the insertion hole of the flange of the fastener to threadedly engage the bolt with the nut, and inserting the nut and the clamping legs of the fastener with the bolt into a mounting hole of the workpiece to bring the flange into juxtaposition with the workpiece;  
 engaging either a general-purpose tool or a portion of the workpiece with the at least two linear sides of the flange to prevent the fastener from being rotated upon the rotation of the bolt; and  
 rotating the bolt relative to the fastener to further screw the bolt into the nut so as to pull the nut toward the flange to cause buckling of the clamping legs in such a manner that the buckling portion in each of the clamping legs is expanded radially outward to allow the fastener to be set to the workpiece by clamping the workpiece between the buckled clamping legs and the flange.  
 
     
     
         6 . A fastener as defined in  Claim 3 , wherein the buckling portion in each of the clamping legs is thinner than the remaining portion of the clamping leg to allow a buckling beginning point to be located thereat, the remaining portion including a nut-side leg portion extending from the buckling portion to the nut, and a flange-side leg portion extending from the buckling portion to the flange.  
     
     
         7 . A fastener as defined in  Claim 6 , wherein the nut-side leg portion is relatively thick so as to have a higher strength than the flange-side leg portion, and a region of the nut-side leg portion adjacent to the nut is relatively thin so as to have a lower strength than the remaining region thereof.  
     
     
         8 . A fastener as defined in  Claim 7 , wherein the flange-side leg portion tapers from a wider width at the flange to a narrower width at the buckling portion.  
     
     
         9 . A fastener as defined in  Claim 8 , wherein the flange-side leg portion is longer than the nut-side leg portion.  
     
     
         10 . A fastener as defined in  Claim 6 , wherein the nut-side leg portion has reduced thickness portions at opposite ends thereof adjacent to the nut and to the flange-side leg portion, respectively.