Abstract:
A hand-held power performs three operations, selectively. A first operation corrects the setting of an improperly set self-piercing rivet. A second operation removes a self-piercing rivet from workpieces. A third operation sets a solid rivet, which may replace a removed self-piercing rivet. For performing these operations, three interchangeable sets of components are provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
         [0001]    This application claims the benefit of Japanese patent application No. 2003-160438 filed Jun. 5, 2003, incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention is concerned with an apparatus capable of selectively performing several operations relating to rivets, more particularly, a first operation in which improper setting of a self-piercing rivet is corrected, a second operation in which a self-piercing rivet is removed from workpieces, and a third operation in which a solid rivet is set, in place of a removed self-piercing rivet, for example.  
           [0003]    A self-piercing rivet comprises a large-diameter head and a hollow shaft extending from the head. Riveting apparatus for joining workpieces by means of self-piercing rivets includes a punch and a cooperable die. The punch engages the head of the rivet and presses the shaft of the rivet through workpieces toward the die, which spreads the shaft to set the rivet.  
           [0004]    Self-piercing rivets are used in the automotive industry, for example, to join pieces of sheet material. When properly set, the head of a rivet is pressed into a first workpiece, almost flush with a surface thereof, and leg portions of the shaft of the rivet pierce a second workpiece and are spread apart while remaining therein. Because no rivet penetration hole is formed in an exposed surface of the latter workpiece, there is no appearance impairment and no opening through which water or sound, for example, can penetrate.  
           [0005]    There are occasions in which a self-piercing rivet is improperly set and in which it is desired to correct the setting. There are other occasions in which it is desired to remove a self-piercing rivet and to replace it with a solid rivet. There are prior art apparatuses for performing some of these functions, but not for performing all of these functions conveniently in a single apparatus. See, for example, Laid-open Utility Model Application No. S62-6943/1987 Gazette (Published Utility Model No. H3-31466/1991 Gazette) and Laid-open Utility Model Application No. H5-93639/1993 Gazette (Published Utility Model No. H7-47161/1995 Gazette) disclosing tools for removing solid rivets set in workpieces; U.S. Pat. No. 4,365,401 disclosing a tool capable of removing solid rivets set in workpieces, and also capable of setting solid rivets in workpieces; and Published Japanese Translation of Patent, No. H9-500059/1997 Gazette (corresponding to U.S. Pat. No. 5,722,144) disclosing a tool capable of removing self-piercing rivets set in workpieces and also capable of setting solid rivets in workpieces after self-piercing rivets have been removed.  
         BRIEF DESCRIPTION OF THE INVENTION  
         [0006]    The present invention provides a simple apparatus capable, selectively, of correcting the setting of an improperly set self-piercing rivet, of removing a set self-piercing rivet, and of setting a solid rivet in place of a removed self-piercing rivet.  
           [0007]    In a preferred embodiment, an apparatus for use in correcting the setting of self-piercing rivets improperly set in workpieces, for use in removing self-piercing rivets from workpieces, and for use in setting solid rivets in workpieces, comprises a frame having a pair of arms with portions spaced apart to provide a gap for receiving workpieces between opposed positions of the arms, a die support at one of said positions and a punch support at the other of said positions, the punch support being reciprocative with respect to the die support, and three exchangeable sets of punch-and-die components, each set having components constructed for mounting at said die support and at said punch support, respectively, wherein a first of said sets of components is constructed to correct the setting of an improperly set self-piercing rivet, a second of said sets of said components is constructed to remove a set self-piercing rivet, and a third of said sets of components is constructed to set a solid rivet. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The invention will be further described in conjunction with the accompanying drawings, which illustrate a preferred (best mode) embodiment of the invention, and wherein:  
         [0009]    [0009]FIG. 1(A) is a sectional view showing a self-piercing rivet that has been insufficiently pressed into workpieces;  
         [0010]    [0010]FIG. 1(B) is a sectional view showing a self-piercing rivet that has been excessively pressed into workpieces;  
         [0011]    [0011]FIG. 2 is a side elevation view of a hand-held power tool utilizing the invention;  
         [0012]    [0012]FIGS. 3-5 are perspective views of sets of components used with a tool of FIG. 2, for example, to perform different operations with regard to rivets;  
         [0013]    FIGS.  6 (A) and  6 (B) are sectional views showing use of apparatus in accordance with the invention for correcting the setting of an improperly set self-piercing rivet;  
         [0014]    FIGS.  7 (A) and  7 (B) are sectional views showing use of apparatus in accordance with the invention for removing a self-piercing rivet from workpieces; and  
         [0015]    FIGS.  8 (A) and  8 (B) are perspective views showing the setting of a solid rivet in workpieces. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    As mentioned earlier, there are occurrences in which a self-piercing rivet has been improperly set. For example, as shown in FIG. 1(A), the head  5  of a rivet  1  has not been sufficiently pressed into a workpiece  3  to be joined to a workpiece  2 , and in FIG. 1(B), a rivet has been excessively pressed into the workpieces. As later described, the rivet  1  shown in FIG. 1(A) can be re-set by apparatus of the invention by pressing the rivet further into the workpieces. In the occurrence shown in FIG. 1(B), the apparatus of the invention can be used to expel the rivet from the workpieces, as later described. A further example of improper setting of a self-piercing rivet involves a rivet that becomes tilted when it is pressed into workpieces. Using the invention, it may be possible to correct such improper setting by resetting the rivet, but if necessary, the rivet can be expelled from the workpieces.  
         [0017]    [0017]FIG. 2 shows a hand-held power tool  10  for performing various operations in accordance with the invention. In the form shown, the tool comprises a C-frame  15  having a pair of arms with portions spaced apart to provide a gap for receiving workpieces between opposed positions near the tips of the arms. One of these positions has a die support  17 , and the other has a punch support  18  which can be reciprocated with respect to the die support  17  as indicated by arrow  26 . The die support  17  has a hole  19  (preferably cylindrical) for accommodating and holding a die. The punch support  18  comprises a rod the tip of which has a hole  21  (preferably cylindrical) for accommodating and holding a punch.  
         [0018]    The tool  10  has a body or housing  22  with a motor  27  for moving the punch support  18  reciprocatively with respect to the die support  19 . The motor may be an electric motor powered by a battery  29  (preferably rechargeable). The electric motor may be a linear motor or a rotary motor provided with a mechanism for converting rotary motion to linear motion. Instead of the battery  29 , a power cord may be provided for supplying the motor from an electrical outlet.  
         [0019]    Instead of an electric motor and battery, the motor may comprise an air pressure piston/cylinder device supplied with compressed air from a remote air compressor (not shown). A hydraulic motor with a piston/cylinder device may also be used, with hydraulic fluid being supplied from an internal or external pump, for example. The power tool  10  has a handle  23 , by which an operator holds the tool, and the handle has a trigger  25  for controlling the actuation of the motor, which drives the punch support  18  in a conventional manner. Various conventional devices (not shown) may be provided for selecting movement of the punch support  18  toward or away from the die support  17 , or the drive mechanism which moves the punch support  18  may be designed to advance the punch support toward the die support when the trigger  25  is pressed and to retract the punch support to its original rest position when the trigger  25  is released.  
         [0020]    [0020]FIGS. 3-5 show interchangeable sets of components used in the performance of different operations relating to riveting.  
         [0021]    [0021]FIG. 3 shows a set of components  11  used for resetting an improperly set self-piercing rivet. These components include a cylindrical die base  33  which fits in the die receiving hole  19  of the die support  17 , a die  30  comprising a cylindrical main die portion  34  having a shaft  37  the diameter of which matches a support hole  35  formed in the die base  33 , and a punch  31  with a head  41  and a cylindrical base  42  which fits in the punch receiving hole  21  of the punch support  18 . The base  42  is detachably secured in the punch receiving hole  21  by a set screw  43  as shown in FIG. 2. The die  30  can be selected from among the different types of dies currently used for setting self-piercing rivets, depending on the size of the rivet, for example, and can be detachably secured in the die base  33  by means of a set screw  38  threaded into the die base and engaging the shaft  37 . The die base  33  is detachably secured in the die receiving hole  19  by a set screw  39  as shown in FIG. 2.  
         [0022]    [0022]FIG. 4 shows a set of components  13  used in removing (punching out) a self-piercing rivet from workpieces. These components include a cylindrical punching out die  45  detachably secured to the die support  17  as disclosed with regard to die base  33  of FIG. 3, and a punch  46  detachably secured to the punch support  18  as disclosed with regard to the punch  31  of FIG. 3. The punch  46  has a head  47  and a base  49 . The die  45  has a passage  70  through which a rivet can be expelled by the punch  46 .  
         [0023]    [0023]FIG. 5 shows a set of components  14  used for setting a solid rivet  54  having a head  45  and a solid shaft  57 . These components include a die base  58  detachably secured in the die receiving hole  19  by set screw  39  (like die base  33 ) with a hole  61  for receiving a shaft  62  extending from a main die portion  60  of a die  51 , and detachably secured in hole  61  by a set screw  63 . The main die portion  60  has a concavity  59  for receiving the head  55  of the rivet  54 . A punch  53  is detachably secured in the punch receiving hole  21  by the set screw  43 .  
         [0024]    FIGS.  6 (A) and  6 (B) show an operation in which the punch  31  and die  30  of FIG. 3 are used to correct the setting of an improperly set self-piercing rivet  65 . To perform this operation, the components  11  are mounted on the tool  10  in the manner previously described, and the workpieces  66  and  67  are placed in the gap between the arms of the C-frame  15  with the rivet  65  aligned with the die  30  and the punch  31 . Then, as shown in FIG. 6(A), when the trigger  25  is pressed to advance the punch toward the die, the punch  31  presses on the head of the rivet  65 , which has been insufficiently set into the workpiece  67 , to reset the rivet as shown in FIG. 6(B) for properly joining the workpieces  66  and  67 .  
         [0025]    FIGS.  7 (A) and  7 (B) show an operation in which a self-piercing rivet is removed from workpieces  66  and  67  by the apparatus of the invention. To perform this operation, the punch  46  and the die  45  are mounted on the arms of the C-frame  15 , as previously described, and the workpieces  66  and  67  are placed in the gap between the arms with the rivet  69  aligned between the punch and the die. In the example shown, the self-piercing rivet  69  has been excessively pressed into the workpieces. To remove the rivet  69  from the workpieces, the trigger  25  of the tool  10  is pressed to engage the head  47  of the punch with the head of the rivet  69 , as shown in FIG. 7(A), and the punch is advanced into the hole  70  of the die  45  to expel the rivet from the workpieces. As shown in FIG. 7(B), the diameter of the head  47  of the punch is substantially the same as the diameter of the head of the rivet  69  but is slightly smaller than the diameter of the hole  70 .  
         [0026]    FIGS.  8 (A) and  8 (B) show an operation in which a solid rivet  54  is set in workpieces  66  and  67  having a hole  71  formed by the punch  46  during expulsion of a self-piercing rivet. To perform this operation, the components  14  shown in FIG. 5 are mounted on the arms of the C-frame  15 , with the head  55  of the rivet  44  received in the concavity  59  of the die  51 , and the workpieces  66  and  67  are placed in the gap between the arms, with the hole  71  receiving the shaft  57  of the rivet  54 . When the trigger  25  is pressed to advance the punch  53  toward the die, the end of the solid shaft  54  of the rivet is flattened and expanded as shown in FIG. 8(B).  
         [0027]    While a preferred embodiment of the invention has been shown and described, it will be apparent that changes can be made without departing from the principles and the spirit of the invention, the scope of which is defined in the accompanying claims. For example, the invention may be used in clinching.