Abstract:
A blind rivet is provided that is operable for insertion into a workpiece. The blind rivet can include a body portion having a first end and second end. The body portion can include a radial flange formed at the first end and can define a bore extending through the body portion. The rivet can include a mandrel with a mandrel head operable to engage the second end of the body portion. The mandrel head can be larger than the bore and can be coupled to a stem. The stem can be configured to pass through the bore and the flange to enable the body portion to engage the workpiece. The radial flange can also include a plurality of bearing surfaces adapted to be coupled to at least one tool for receipt of a predetermined torsional load at the radial flange to cause failure of the body portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application No. 60/652,027, filed on Feb. 11, 2005. The disclosure of the above application is incorporated herein by reference. 

   FIELD 
   The present disclosure relates to fastening system and more particularly to a frangible blind rivet. 
   BACKGROUND 
   The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
   Generally blind rivets include a mandrel and a tubular shell. The mandrel typically has a pulling stem with a radially enlarged head attached at one end. An axial bore may be formed through the length of the shank and the flange. Part of the pulling stem of the mandrel may be located within the bore, with the enlarged head abutting against the end of the shank remote from the flange. The rest of the pulling stem can extend beyond the flange away from the tubular shell. The tubular shell can generally have a cylindrical shaped shank with a radial flange formed at one end of the shank for engaging a face of the workpiece. A portion of the shell can be of a reduced cross-section or form a breakneck on the part of the stem that is located within the shank. 
   Typically, in order to set the blind rivet, the flange can be held stationary whilst the exposed part of the pulling stem is pulled axially away from the flange so that the enlarged head is forced to pass through the bore. Because the diameter of the enlarged head is substantially larger than the bore, it can cause the shank to plastically deform to form an annular bulge or fold, which can project radially outwardly from the shank. Thus the radially outward bulge forms the blind head and can secure the opposite side of the workpiece to that of the flange. Once the pulling force on the stem exceeds a predetermined amount, the breakneck can break to leave the rivet set. The rest of the stem can then be removed and discarded. 
   In many situations, the rivet may need to be removed from the workpiece in order to repair or replace the workpiece. Typically, in order to remove the blind rivet from the workpiece, the breakneck section is drilled out using a suitable piece of equipment and then the rivet may be tapped out of the workpiece, using such equipment as a mallet. However, in situations where the rivet may not be easily accessible with a drill or a mallet, the workpiece may have to be damaged in order to access the rivet to remove it, or the workpiece may have to be scrapped. Accordingly, it is desirable to provide a blind rivet that can be more easily removed from a workpiece. 
   SUMMARY 
   The present invention provides a blind rivet that is operable for insertion into a workpiece. The blind rivet includes a body portion including a radial flange formed at a first end and a bore extending through the body portion. The rivet includes a mandrel including a mandrel head operable to engage a second end of the body portion. The mandrel head is larger than the bore and is coupled to a stem. The stem is operable to pass through the bore and the flange to cause the mandrel head to deform onto the workpiece. The radial flange also includes a plurality of bearing surfaces operable to engage at least one tool in order to remove the rivet from the workpiece. 
   Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 

   
     DRAWINGS 
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       FIG. 1  is a perspective side view of a blind rivet according to the principles of the present invention; 
       FIG. 2  is a second perspective side view of the blind rivet of  FIG. 1 ; 
       FIG. 3  is a top view of the rivet of  FIG. 1 ; 
       FIG. 4  is a side view of the rivet of  FIG. 1 ; 
       FIG. 5  is a perspective side view of a blind rivet according to a second embodiment of the present invention; 
       FIG. 6  is a top view of the rivet of  FIG. 5 ; 
       FIG. 7  is a side view of the rivet of  FIG. 5 ; 
       FIG. 8  is a perspective side view of a blind rivet according to a third embodiment of the present invention; 
       FIG. 9  is a top view of the rivet of  FIG. 8 ; 
       FIG. 10  is a side view of the rivet of  FIG. 8 ; 
       FIG. 11  is an environmental view of the rivet of  FIG. 1  prior to insertion into the workpiece; 
       FIG. 12  is an environmental view of the rivet of  FIG. 1  in a first position prior to deformation; 
       FIG. 13  is an environmental view of the rivet of  FIG. 1  in a second position after deformation of the rivet into a locked position; 
       FIG. 14  is an environmental view of the rivet of  FIG. 1  in preparation to be removed from a workpiece; and 
       FIG. 15  is an environmental view of the rivet of  FIG. 1  upon removal of the rivet from the workpiece. 
   

   DETAILED DESCRIPTION 
   The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. Although the following description details the configuration of a rivet that is capable of removal from a workpiece by a wrench, it will be understood that various other instruments could be employed to remove the rivet, and the rivet may contain the appropriate features to engage these instruments. 
   With reference now to  FIGS. 1 through 12 , a rivet  10  is shown. The rivet  10  can include a body  12  and a mandrel  14 . The body  12  can be generally cylindrical and can be comprised of any material that is capable of plastically deforming in tension and failing in shear, such as aluminum or steel. The body  12  can have a generally uniform exterior  18 ; however, the exterior  18  can include a plurality of serrations  20 , as shown in  FIGS. 5 ,  6  and  7 , to enable the body  12  to further engage a workpiece (not specifically shown). 
   The body  12  can further include a first end  22 , a second end  24  and a central bore  26  ( FIG. 13 ). The first end  22  can be operable to interface with the mandrel  14  and plastically deform to secure a workpiece, as will be discussed in greater detail herein. The second end  24  of the body  12  can include a radial flange  28  ( FIGS. 1 ,  5  and  8 ), which can generally be formed onto the second end  24 ; however, any suitable post processing step could be used to couple the radial flange  28  to the second end  24  of the body  12 , such as welding or adhesives. The radial flange  28  may comprise a plurality of flat portions  30  to form a generally hexagonal head, or in the alternative, as shown in  FIGS. 8 ,  9  and  10 , the radial flange  28  may be oval in shape. The shape of the radial flange  28  can generally be such that a first tool  32  (shown in  FIG. 17 ) can engage the radial flange  28 . The first tool  32  can be any suitable tool including a jaw  67  capable of grasping the radial flange  28 , such as a wrench, channel locks, socket wrench or the like. Thus, the radial flange  28  may be of any shape operable to engage the jaw  67  of the first tool  32 , as will be discussed in greater detail herein. 
   The second end  24  of the body  12  can further include an annular groove  34 . The annular groove  34  can generally be formed on the exterior  18  of the body  12 , typically adjacent to the radial flange  28 ; however, the annular groove  34  can generally be formed at any desired position on the body  12  (for example, the annular groove  34  could be formed at any location 25% to 75% along the body  12  from the first end  22 ). Although the groove  34  is described herein as being annular, it will be understood that the actual shape of the groove  34  could be any shape that corresponds with the shape of the body  12 . In addition, it will be understood that the annular groove  34  may be located at any desired position on the body  12 , and can alternatively be formed on an interior surface of the body  12  (not shown). The annular groove  34  can have a rectangular cross-section as shown in  FIGS. 12 and 13 , but any other cross-section, such as pointed or rounded, could be employed. The annular groove  34  has a width W and a depth X (as best shown in  FIG. 12 ) configured to enable the radial flange  28  to separate from the second end  24  of the body  12  during the application of a torsional force, as will be described in greater detail herein. Further, it will be understand that although only one annular groove  34  is illustrated herein, multiple annular grooves  34  could be employed. The central bore  26  can extend from the first end  22  to the second end  24  of the body  12  and can be operable to receive the mandrel  14 , as best shown in  FIG. 12 . 
   The mandrel  14  can include a mandrel head  36  coupled to a stem  38 , as best shown in  FIG. 12 . With continuing reference to  FIG. 12  and additional reference to  FIGS. 1 through 14 , the mandrel head  36  can generally include a conical portion  40  coupled to a cylindrical base  42 . The cylindrical base  42  can have a diameter D 1 , which can generally be greater than a diameter D 2  of the central bore  26  such that the mandrel head  36  can be unable to pass through the central bore  26 . It will be understood, however, that any appropriate shape could be employed for the mandrel head  36 , as long as the diameter D 1  of the mandrel head  36  is greater than the diameter D 2  of the central bore  26 . The mandrel head  36  can typically be formed onto the stem  38 . 
   The stem  38  can include a first end  44  coupled to the mandrel head  36  and a second end  46 . The stem  38  can be generally cylindrical with a diameter D 3 , which can be at least slightly less than the diameter D 2  of the central bore  26 ; however, any suitable shape and diameter could be employed. The first end  44  of the stem  38  can include a breakneck section  48 , which can be operable to enable the stem  38  to separate from the mandrel head  36 . The breakneck section  48  can generally include a first tapered portion  50 , which can meet a second tapered portion  52  at a point  54 . The thickness T 2  of the point  54  is such that the first end  44  of the stem  38  can be severed from the second end  46  of the stem  38  upon the application of a pre-determined tensile force, as will be discussed in greater detail herein. 
   The second end  46  of the stem  38  can include a tapered section  56 , which can terminate in a generally square portion  58 . The portion  58  is shown as having a generally square cross-section; however, the portion  58  may be sized in any appropriate shape to interface with a pulling tool (not shown). The pulling tool can be operable to apply a tensile force T to the stem  38  of the mandrel  14  via the portion  58  to set the rivet  10 . 
   With additional reference to  FIGS. 12 ,  13 ,  14  and  15 , in order to set the rivet, the body  12  can be first slid onto the mandrel  14 , such that the mandrel head  36  can abut the first end  22  of the body  12 . Next, the assembled rivet  10  can be placed into a hole  60  formed in a workpiece  62  ( FIG. 12 ). Then, the pulling tool (not shown) may be coupled to the portion  58  of the stem  38  of the mandrel  14 , to begin the application of the tensile force T to the mandrel  14 . The application of the tensile force T can cause the mandrel head  36  to apply a compression force to the first end  22  of the body  12 . The compressive loading of the first end  22  of the body  12  can cause the first end of the body to  12  expand outward. In particular, as the diameter D 1  of the mandrel head  36  is greater than the diameter D 2  of the central bore  26 , the size of the mandrel head  36  coupled with the tensile force T can cause the first end  22  of the body  12  to plastically deform into an annular bulge  64  as shown in  FIG. 13 . 
   Once the first end  22  of the body  12  has plastically deformed to a pre-determined amount, the continued application of the tensile force T can cause the breakneck portion  48  to fracture, severing the second end  46  of the stem  38  from the first end  44  of the stem  38 . After the second end  46  of the stem  38  has detached from the breakneck portion  48 , the rivet  10  can be firmly secured to the workpiece  62 . 
   With additional reference to  FIG. 14 , in order to remove the rivet  10  from the workpiece  62 , a second tool  66  can be coupled to the first end  22  of the body  12 , around the annular bulge  64 . The second tool  66  can be any suitable tool including a jaw  67  that is capable of grasping the annular bulge  64 , such as a wrench, channel locks, socket wrench or the like. Next, the first tool  32  can be coupled to the second end  24  of the body  12 , around the radial flange  28 . Then, the first tool  32  can be rotated while the second tool  66  is held fast, to create a torsional load that is transmitted along the radial flange  28 . However, it should be noted that when the tubular body includes the plurality of serrations  20  as illustrated in  FIG. 5 , it may not be necessary to use the second tool  66  as the serrations  20  can serve to firmly hold the body  12  within the workpiece  62 . 
   Once the torsional load reaches a pre-determined amount, the body  12  of the rivet  10  will fail at the annular groove  34 , as shown in  FIG. 15 . In particular, the torsional force from the first tool  32  will cause the body  12  of the rivet  10  to fail in shear. After the radial flange  28  is separated from the rivet  10 , the remaining body  12  of the rivet  10  can then be pulled out of the workpiece  62  by the first tool  32  or tapped out of the workpiece  62  using a mallet and chisel, for example (not shown).