Blind Rivet and Removal Method Thereof

Abstract

The invention relates to a blind rivet (R) of the type which is used to position at least two elements ( 100 and 200 ) alongside one another and to fasten same and which is installed using an installation tool. The invention is characterised in that it comprises a bushing ( 300 ) which is made from one single piece and which is preformed from a single tapered part ( 330 ) that is located between the two support surfaces ( 311 and 321 ), with the elements to be assembled being defined initially or by means of deformation by the bushing. The invention also relates to a method of removing said rivet.

1 . Blind rivet (R) of the type intended for the coupling and the tack riveting together of at least two elements ( 100  and  200 ), said rivet being positioned by a setting tool,
 the rivet (R) being an assembly comprising a deformable hollow sleeve ( 300 ) and a breakable mandrel ( 400 ) positioned within said sleeve,   the assembly being positioned and traversing two substantially coaxial openings ( 110  and  120 ) arranged in the elements ( 100  and  200 ) to be assembled,   the sleeve ( 300 ) comprising a body having two ends,   a first end ( 310 ) comprising a preformed head for defining a first support surface ( 311 ) on the external surface ( 120 ) of a first element ( 100 ), and a second end ( 320 ) which, under the action of a tension deformation (arrow F) on the mandrel ( 400 ), forms a bulb that defines a second support surface ( 321 ) on the external surface ( 220 ) of said second element ( 200 ),   the prolongation of the effort (arrow F) causing the two support surfaces ( 311  and  321 ) to be drawn nearer each other and consequently also drawing nearer together the two elements ( 100  and  200 ) to be assembled, and causing the crimping of the first end of the mandrel, characterised in that it comprises a sleeve ( 300 ) which, integrally formed of one and the same piece, is preformed from a single tapered portion ( 330 ) positioned between the two support surfaces ( 311  and  321 ), said tapered portion not interfering with the tension efforts, while facilitating the deformation of the sleeve and permitting the establishment of an installed tension.   
   
   
       2 . Rivet (R) according to  claim 1 , characterised in that the tapered portion ( 330 ) consists of a portion of the sleeve ( 300 ) having an exterior diameter less than the exterior diameter of the remainder of the sleeve ( 300 ). 
   
   
       3 . Rivet (R) according to  claim 1 , characterised in that the tapered portion ( 330 ) consists of a portion of the sleeve ( 300 ) having an interior diameter greater than the interior diameter of the remainder of the sleeve ( 300 ). 
   
   
       4 . Rivet (R) according to  claim 1 , characterised in that the length (l) of the tapered portion ( 330 ) is less than the smallest span (L) separating the external surfaces ( 120  and  220 ) of the elements ( 100  and  200 ) to be fastened/coupled. 
   
   
       5 . Rivet (R) according to  claim 1 , characterised in that the tapered portion ( 330 ) is separated from the support surface ( 311 ) defined by the head of the sleeve ( 300 ) by a portion having a greater thickness. 
   
   
       6 . Rivet (R) according to  claim 1 , characterised in that the head of the sleeve ( 300 ) is generally shaped like a hollow cylinder, traversed by the mandrel ( 400 ), having a radial bulge at the level of its upper end as well as at the level of the surface defining the leaning ( 311 ) with the element ( 100 ) to be assembled. 
   
   
       7 . Rivet (R) according to  claim 1 , characterised in that said mandrel ( 400 ) is preformed from a plurality of grooves with which the setting tool or removing tool engages. 
   
   
       8 . Rivet (R) according to  claim 1 , characterised in that said mandrel ( 400 ) is preformed from a breakneck groove dimensioned for breaking and positioned at a sufficient distance from the head of the sleeve ( 310 ) in order to permit the recovery of the mandrel ( 400 ) on the basis of the removal of the rivet. 
   
   
       9 . Method of removing a rivet (R) according to  claim 1 , characterised in that it consists of resuming the tensile force (arrow F′) which ensures a rupture of the sleeve ( 300 ) at the level of its bulb so as to permit removal, by way of the fastening openings ( 110  and  120 ), of the mandrel ( 400 ) and of a first portion of the sleeve ( 300 ′) as well as the falling away of the portion of the bulb ( 300 ″) remaining on the exterior.