Patent Publication Number: US-2023160030-A1

Title: Method of manufacturing blind rivet

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a method of manufacturing rivets, especially to a method of manufacturing blind rivets by which the blind rivet manufactured provides excellent support strength during riveting and fixation of workpieces for secure and reliable fastening of the workpieces. Thereby the workpieces are securely fastened without easy loosening and the blind rivet is more convenient to use. 
     Description of Related Art 
     For permanent connection of workpieces such as sheet metal, mechanical structure, etc., blind rivets are used. Once the workpieces are fixed by the blind rivet, they are hard to separate from each other. 
     A blind rivet mainly includes a sleeve, a mounting flange projecting from one end of the sleeve, and a mandrel inserted through the sleeve and provided with an against portion on one end thereof. Thus the mandrel is abutting against an outer side of one end of the sleeve, opposite to the end of the sleeve with the flange by the against portion. While in use, insert the sleeve into a mating hole formed in workpieces and then the mounting flange is abutting against one end of the mating hole. Then the mandrel is pulled by a hand tool so that the against portion of the mandrel presses the sleeve toward the mounting flange. Thus the workpieces are clamped and fastened between a deformed part of the sleeve caused by squeezing of the against portion of the mandrel and the mounting flange. At the same time, the mandrel is drawn by the hand tool and broken. Thereby the fastening is complete. 
     Although the blind rivet mentioned above shows expected results, the above blind rivet provides limited support strength after the workpieces being riveted by the blind rivet and the workpieces still get loose. This cause inconvenience in use. 
     Thus there is room for improvement and there is a need to provide a method of manufacturing blind rivets, which address issues of rivets produced by the methods available now. 
     SUMMARY OF THE INVENTION 
     Therefore, it is a primary object of the present invention to provide a method of manufacturing blind rivets by which the blind rivet manufactured provides excellent support strength during riveting and fixation of workpiece for secure and reliable fastening of the workpiece. Thereby the workpiece is tightly fastened without easy loosening and the blind rivet is more convenient to use. 
     In order to achieve the above object, a method of manufacturing blind rivets according to the present invention includes the following steps while the blind rivet manufactured includes a threaded rod and an outer tube. 
     First cut a steel wire rod according to a length required to get a rod and form a head portion at one end of the rod. Then perform threading on an outer surface of the rod to form outer threads and carry out heat treatment including quenching and tempering at 380° C.±50° C. to get the threaded rod. 
     Next cut a steel wire rod according to a length required to get a tube and form a through hole axially penetrating the tube and corresponding to the threaded rod. Then form a mounting portion at an outer edge of one end of the tube, carry out optical heat treatment at 1100° C.±100° C. with a moveable heat source, and perform electroplating to get the outer tube. 
     Lastly, the threaded rod is inserted into the through hole of the outer tube and the head portion of the threaded rod is exposed outside and abutting against an end of the outer tube opposite to the end of the outer tube with the mounting portion. 
     A protruding locking portion which is corresponding to the mounting portion is formed on an inner surface of the through hole of the outer tube. 
     The optical heat treatment carried out on the outer tube is laser heat treatment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein: 
         FIG.  1    is a block diagram of a manufacturing process of an embodiment according to the present invention; 
         FIG.  2    is a schematic drawing showing an embodiment in use according to the present invention; 
         FIG.  3    is another schematic drawing showing a rivet manufactured by an embodiment in use according to the present invention; 
         FIG.  4    is a further schematic drawing showing a rivet manufactured by an embodiment in use according to the present invention; 
         FIG.  5    is a further schematic drawing showing a rivet manufactured by an embodiment in use according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In order to learn technical content, purposes and functions of the present invention more clearly and completely, please refer to the following detailed descriptions, figures and reference signs. 
     Refer to  FIG.  1    and  FIG.  2   , a blind rivet produced by the present method mainly includes a threaded rod  1  and an outer tube  2 . A method of manufacturing blind rivets includes the following steps. 
     First cut a steel wire rod according to a length required to get a rod and form a head portion  11  at one end of the rod. Then perform threading on an outer surface of the rod to form outer threads  12 , and carry out heat treatment including quenching and tempering at 380° C.±50° C. to get the threaded rod  1 . 
     In the beginning, cut a steel wire rod according to a length required to get a tube and form a through hole  21  which is axially penetrating (a center/central axis of) the tube and corresponding to the threaded rod  1 . Then form a mounting portion  22  at an outer edge of one end of the tube and a protruding locking portion  23  on an inner surface of the through hole  21  of the tube while the protruding locking portion  23  is corresponding to the mounting portion  22 . Next carry out optical heat treatment such as laser heat treatment at 1100° C.±100° C. with a moveable heat source and then perform electroplating to get the outer tube  2 . 
     While in use, the threaded rod  1  is inserted into the through hole  21  of the outer tube  2  and the head portion  11  of the threaded rod  1  is exposed outside and abutting against an end of the outer tube  2  opposite to the end of the outer tube  2  with the mounting portion  22 . Then the outer tube  2  is inserted through a fixing hole  31  formed in workpiece  3  and the mounting portion  22  is abutting against an outer side at one end of the fixing hole  31 , as shown in  FIG.  2   . A rivet tool  4  is used to pull the threaded rod  1  so that the head portion  11  of the threaded rod  1  presses the outer tube  2  toward the mounting portion  22 , as shown in  FIG.  3   . The protruding locking portion  23  which is located on an inner surface of the through hole  21  of the outer tube  2  and corresponding to the mounting portion  22  is also locked and fixed on a periphery of the threaded rod  1 . Along with squeezing and deformation of the outer tube  2  caused by the head portion  11 , a deformed part of the outer tube  2  is also abutting against the workpiece  3 , as shown in  FIG.  4   . Lastly the threaded rod  1  is broken due to pulling of the rivet tool  4  and the workpiece  3  is clamped and fixed between the mounting portion  22  and the deformed part of the outer tube  2  caused by squeezing of the head portion  11  of the threaded rod  1 . At the same time, the threaded rod  1  is also locked and fixed by the protruding locking portion  23  in the through hole  21  of the outer tube  2 , without coming off, as shown in  FIG.  5   . 
     Under the same specification, the blind rivet produced by the present method has much higher tensile strength than the blind rivet available now so that the blind rivet manufactured by the present method is more convenient to use. 
     In summary, the blind rivet produced by the present method provides excellent support strength during riveting and fixation of the workpiece for secure and reliable fastening of the workpiece. Thereby the workpiece is securely fastened without easy loosening and the blind rivet is more convenient to use. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalent.