Abstract:
A rivet machine is provided. The rivet machine employs a die including a die body that has an inner wall with a pair of retaining ribs or projections extending inwardly therefrom. In use, the rivet pushes a slug from a workpiece within which it is mounted and into an opening of the die. The projections engage and retain the slug within the inner wall. According to further aspects, the pair of retaining ribs are diametrically opposed around the inner wall. Each of the retaining ribs has two converging surfaces that form an angle of between 90 and 150 degrees. In yet another aspect, the projections can be discontinuous such that a first retaining rib is longitudinally offset on the inner wall from a second retaining rib.

Description:
FIELD 
       [0001]    This present invention relates generally to a fastener machine and more particularly to a die for a rivet machine. 
         [0002]    Rivet machines generally include a ram or punch that is configured to engage and drive a rivet through workpieces to join the workpieces together. In general, when the rivet is driven into the workpieces by the punch, the rivet will urge portions of the workpiece, or a slug, into an opening of the die to make room for the rivet. In some instances, the slug may unfavorably become attached or stuck to the workpiece and/or against the rivet. In such an event, the slug may be carried on the workpiece with the finished component and later fall off. In some examples, the slug may fall off of a workpiece that has been assembled into a completed product (such as a door of a vehicle) that could later cause mechanical problems and/or noise from rattling. 
         [0003]    In accordance with the present invention, a rivet machine is provided. The rivet machine employs a die including a die body that has an inner wall with a pair of retaining ribs or projections extending inwardly therefrom. In use, the rivet pushes a slug from a workpiece within which it is mounted and into an opening of the die. The projections engage and retain the slug within the inner wall. According to further aspects, the pair of retaining ribs are diametrically opposed around the inner wall. Each of the retaining ribs has two converging surfaces that form an angle of between 90 and 150 degrees. In yet another aspect, the projections can be discontinuous such that a first retaining rib is longitudinally offset on the inner wall from a second retaining rib. 
         [0004]    Further advantageous and areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       DRAWINGS 
         [0005]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0006]      FIG. 1  is a perspective view showing a rivet machine; 
           [0007]      FIG. 2  is a partial cross-sectional view taken through the rivet machine of  FIG. 1 ; 
           [0008]      FIG. 3  is a perspective view of a die of the rivet machine shown in  FIG. 1 ; 
           [0009]      FIG. 4  is a top plan view of the die of  FIG. 3 ; 
           [0010]      FIG. 5  is a longitudinal cross-sectional view of the die taken along line  5 - 5  of  FIG. 4 ; 
           [0011]      FIG. 6  is a detail view of an upper portion of the die of  FIG. 5 ; 
           [0012]      FIG. 7  is a first side view of the die of  FIG. 3 ; 
           [0013]      FIG. 8  is a second side view of the die of  FIG. 3 ; 
           [0014]      FIG. 9  is a third side view of the die of  FIG. 3 ; 
           [0015]      FIG. 10  is a bottom plan view of the die of  FIG. 3 ; 
           [0016]      FIGS. 11-15  illustrate an exemplary sequence for driving a rivet into first and second workpieces according to one example of the present teachings; 
           [0017]      FIG. 16  is a perspective view of a rivet shown driven into the first and second workpiece according to the present teachings; 
           [0018]      FIG. 17  is a prior art view of a slug that has remained attached to a newly introduced rivet; 
           [0019]      FIG. 18  is a cross-sectional view of a die button constructed in accordance to additional features of the present teachings; and 
           [0020]      FIG. 19  is a cross-sectional view of a die button constructed in accordance to other features of the present teachings. 
       
    
    
       [0021]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0022]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0023]    Referring to  FIG. 1 , a rivet setting machine  21  includes a C-frame  23  which is mounted to an articulated robotic arm  25  for automated movement between various operating positions within an industrial factory. An anvil section  27  of C-frame  23  has a die  29  mounted thereon. A ram assembly  31  is mounted to the opposite end of C-frame  23  and includes an air-over-oil fluid actuated cylinder  33 , a nose piece  35  and a linearly moving punch  37 . Alternately, cylinder  33  can be solely hydraulically, pneumatically, or less preferably, servo-motor actuated. A rivet feeding mechanism  41  is mounted to a generally middle segment of C-frame  23  and is elongated in a direction generally perpendicular to the movement direction of punch  37 . 
         [0024]    A vibratory bowl  43  supplies individualized fasteners, such as a self-piercing rivet  45 , to feeding mechanism  41  via a pneumatically pressurized and flexible hose  47 . When multiple workpiece sheets  49  are inserted between punch  37  and die  29 , punch  37  will thereafter push and set the rivet into the upper surface of the workpieces as they are being compressed against die  29 . Self-piercing rivet  45  is preferably a solid (e.g., not hollow) rivet which punches out a blank or slug ( 150 ,  FIG. 13 ) from the previously unpunched workpiece areas, whereafter the blanks are withdrawn through an aperture in die  29  as will be described in greater detail herein. The rivet ends are generally flush with the adjacent outside surfaces of workpieces  49 . One such self-piercing rivet is disclosed in U.S. Pat. No. 4,130,922 entitled “Headless Riveting System” which issued to Koett on Dec. 26, 1978, which is incorporated by reference herein. 
         [0025]    With particular reference now to  FIGS. 3-9 , the die  29  constructed in accordance to one example of the present teachings will be described in greater detail. The die  29  generally comprises a die body  50  having a main body portion  52  and a base portion  54 . A transition between the main body portion  52  and the base portion  54  is generally provided by a skirt  56 . The skirt  56  includes a relief  60  having a ledge  62 . According to one example, the ledge  62  can be engaged by a head of a fastener (not specifically shown) that mechanically secures the die body  50  to a die block  66  provided on the anvil section  27  (See  FIG. 2 ). The main body portion  52  generally includes flats  70  formed thereon. The main body portion  52  can further include a die button  71 . The die button  71  generally includes an end surface  72  and a raised collar  74  extending proud therefrom. 
         [0026]    The die body  50  defines an opening  78 . The opening  78  can be generally defined by a bore  79  having an inner wall  80  having a generally cylindrical shape and defining an axis  81 . The inner wall  80  of the die body  50  includes a plurality of retaining ribs or projections collectively identified at reference numeral  82 . The projections  82  extend generally inwardly from the inner wall  80  of the die body  50 . The projections  82  include a first pair of projections  84 , a second pair of projections  86 , and a third pair of projections  88 . In the specific example shown, the projections of the respective pairs of projections  84 ,  86 , and  88  are diametrically opposed on the inner wall  80 . According to one example, the projections  82  may be formed on the inner wall  80  of the die body  50  by a wire electrical discharge machining (EDM) process. 
         [0027]    With particular reference now to  FIG. 4 , one of the projections  84  of the projections  82  will be described in greater detail with the understanding that the other projections  86  and  88  of the projections  82  may be constructed similarly. The flute  84  generally comprises a first converging surface  90  and a second converging surface  92 . The first and second converging surfaces  90  and  92  generally cooperate to form a pie or triangular shape. In one example, the first converging surface  90  and the second converging surface  92  form an angle  98  of between 90 and 150 degrees, and more specifically, 120 degrees. The projections  82  generally initiate at the inner wall  80  that defines a first diameter  100  and terminate at a second diameter  102 . According to one example of the present teachings, the first diameter  100  can be substantially about 0.266 inches and the second diameter can be about 0.246 inches. In this regard, the second diameter  102  can be substantially between 90 and 95 percent of the first diameter  100 . As will be described more fully herein, the projections  82  can cooperate to retain a slug subsequent to insertion of a rivet into a workpiece. In this regard, the projections  82  of the die body  50  cooperate to inhibit a slug from unfavorably sticking to or otherwise be attached to the workpiece adjacent to a self-piercing rivet. 
         [0028]    Turning now to  FIGS. 5 and 6 , additional features of the die body  50  will be described. The die body  50  defines a die chute  110  therethrough. The die chute  110  generally extends the entire length of the die body  50  through the main body portion  52 , the skirt  56 , and the base portion  54 . The die chute  110  is generally coaxial with the opening  78 . As will become appreciated from the following discussion, the die chute  110  can be configured to generally accept slugs therethrough subsequent to a rivet installation. In one example, the die chute  110  can define an inner diameter  111 . The inner diameter  111  can be about 0.30 inches. The raised collar  74  includes surfaces  112  that generally converge at an angle  116 . In one example, the angle  116  can be about 20 degrees. The raised collar  74  can extend proud from the end surface  72  a distance  120 . The distance  120  can be about 0.025 inches. 
         [0029]    Turning now to  FIGS. 11-15 , an exemplary sequence for driving a rivet  45  into a first and second workpiece  142  and  144 , respectively will be described. The rivet  45  is a self-piercing rivet.  FIG. 11  generally illustrates a rivet  45  intermediate the nosepiece  35  (as well as the punch  37 ) and the die  29 .  FIG. 12  illustrates the first and second workpieces  142  and  144 , respectively being located generally between the die  29  and the nosepiece  35  (as well as the punch  37 ). In one example, the second workpiece  144  can be located against the raised collar  74 . As is generally known in the art, the self-piercing rivet  45  can be driven through the first and second workpieces  142  and  144  to join the first and second workpieces  142  and  144  together. 
         [0030]      FIG. 13  illustrates the punch  37  initially driving the rivet  45  through the first workpiece  142  and partially into the second workpiece  144 . The driving of the rivet  45  into the first and second workpieces  142  and  144  creates a slug generally identified at reference numeral  150 . The slug  150  generally comprises a first slug portion  152  and a second slug portion  154 . As can be appreciated, the first slug portion  152  includes material from the first workpiece  142  while the second slug portion  154  includes material from the second workpiece  144 . As shown in  FIG. 14 , the rivet  45  has been driven through the second workpiece  144  causing the slug  150  to be generally received into the opening  78  of the die body  50 . At this point, an outer surface of the slug  150  is engaged by the projections  82  extending from the inner wall  80  of the die body  50 . The projections  82  cooperate to generally retain the slug  150  within the opening  78 . In this regard, when the workpieces  142  and  144  are shifted away carrying the newly introduced rivet  45 , the slug  150  is specifically retained by the opening  78  in the die body  50  such that the slug  150  is inhibited from sticking to or otherwise being captured against the newly introduced rivet  45  (as illustrated in  FIG. 17 ). 
         [0031]    With reference to  FIG. 15 , a subsequent rivet  45 ′ is shown being introduced through the first and second workpieces  142  and  144 . In one example, the workpieces  142  and  144  may have been shifted away from alignment between the punch  37  and the die  29  carrying the previously introduced rivet  45 . The subsequent rivet, identified at reference numeral  45 ′ can drive a new slug identified at reference numeral  150 ′ into the opening  78  of the die body  50 . The new slug  150 ′ will tend to urge the previously retained slug  150  into the die chute  110 , where it may be collected with other slugs in the sequence. The process then repeats itself with each subsequent rivet introduction. In some examples, a vacuum may be attached to the die body  50  for drawing air through the die chute  110  in a direction generally from the opening  78  at the main body portion  52  in a direction toward the base portion  54 .  FIG. 16  illustrates the rivet  45  installed into the workpieces  142  and  144 . 
         [0032]      FIG. 18  illustrates a die  229  constructed according to additional features. The die  229  includes a die body  250  and die button  271 . The die button  271  has a raised collar  274 . An opening  278  is generally defined by a bore  279  having an inner wall  280 . Projections, collectively identified at  282  extend inwardly from the inner wall  280 . The projections  282  can include a first projection  284  that is discontinuous from a second projection  286 . The projections  282  can extend at an angle relative to an axis of the inner wall  280 . Projections  282 ′ having first projection portion  284 ′ and second projection portion  286 ′ are shown in a die  229 ′ configuration in  FIG. 19 . The projections  282 ′ are parallel to an axis of an inner wall  280 ′. 
         [0033]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.