Abstract:
A fastener positioning device for a die block including a punch tube arranged to receive the fastener, at least one aperture extending radially out from the tube, at least one displaceable retainer disposed in the at least one aperture, and a resilient ring urging the at least one retainer towards an axis of the punch tube. In an example embodiment of the invention, the aperture includes a first diameter proximate the punch tube and a second, larger diameter radially outside of the first diameter. The retainer may be a ball, the resilient ring may be an O-ring, and the fastener may be a stud or nut.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/288,532, filed Dec. 21, 2009. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to a fastener positioning device, and more specifically to a fastener positioning device for a die block in a stamping press. 
       BACKGROUND OF THE INVENTION 
       [0003]    U.S. Pat. No. 6,021,562, assigned to Haeger, Inc., describes a fastener insertion module for a progressive die that uses a special bisected bushing. The bushing securely holds and positions each fastener in place prior to and during insertion. U.S. Pat. No. 3,452,418, assigned to Penn Engineering, describes a gate for an automatic fastener press. The gate includes a pilot spring extending to a hole of a fastening element such as a nut, for example. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    Example aspects of the present invention broadly comprise a fastener positioning device for a die block including a punch tube arranged to receive the fastener, at least one aperture extending radially out from the tube, at least one displaceable retainer disposed in the at least one aperture, and a resilient ring urging the at least one retainer towards an axis of the punch tube. In an example embodiment of the invention, the aperture includes a first diameter proximate the punch tube and a second, larger diameter radially outside of the first diameter. The retainer may be a ball, the resilient ring may be an O-ring, and the fastener may be a stud or nut. 
         [0005]    In some example embodiments of the invention, the fastener positioning device has a chute portion connected to the punch tube, and the chute portion is arranged to guide the fastener into the punch tube. The fastener may be gravity-fed through the chute portion into the punch tube. The device may also include a punch arranged to travel through the punch tube to install the fastener. In an example embodiment of the invention, the at least one retainer is arranged to be radially displaced by the fastener. 
         [0006]    In some example embodiments of the invention, in response to an axial force upon the fastener in an axial direction, the fastener is axially displaceable in the axial direction to radially outwardly displace the at least one retainer. The at least one retainer may be radially outwardly displaceable such that the fastener is displaceable past the at least one retainer in the axial direction. 
         [0007]    Other example aspects of the present invention broadly comprise a method of installing a fastener in a plate by radially contracting a plurality of retainers with a resilient ring, introducing the fastener through a chute portion, and axially positioning a radial surface of the fastener on the plurality of retainers. The method may include axially displacing the fastener with a punch, radially displacing the retainers with the fastener, and inserting the fastener into a hole in the plate. 
         [0008]    Other example aspects of the present invention broadly comprise a fastener positioning device for a die block including a punch tube arranged to receive a stud or nut, and a plurality of apertures extending radially out from the tube. The tube has an axis and each aperture has a first diameter, a second diameter less than the first diameter, and a respective lip proximate the tube. The fastener positioning device includes a plurality of balls disposed in the plurality of apertures and an O-ring urging the plurality of balls towards the axis. The plurality of balls is radially displaceable by axial displacement of the stud or nut. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention taken with the accompanying drawing figures, in which: 
           [0010]      FIG. 1A  is a perspective view of a cylindrical coordinate system demonstrating spatial terminology used in the present application; 
           [0011]      FIG. 1B  is a perspective view of an object in the cylindrical coordinate system of  FIG. 1A  demonstrating spatial terminology used in the present application; 
           [0012]      FIG. 2  is a cross-section view of a fastener positioning device for a die block, according to an example aspect of the invention; 
           [0013]      FIG. 3  is a detail view of encircled region  3  in  FIG. 2 ; 
           [0014]      FIG. 4  is a detail view of encircled region  3  in  FIG. 2  showing an alternative embodiment of the invention; and, 
           [0015]      FIG. 5  is a partial cross section view of a die block with a fastener positioning device, according to an example aspect of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    At the outset, it should be appreciated that like drawing numbers appearing in different drawing views identify identical, or functionally similar, structural elements. Furthermore, it is understood that this invention is not limited only to the particular embodiments, methodology, materials and modifications described herein, and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims. 
         [0017]    Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the following example methods, devices, and materials are now described. 
         [0018]      FIG. 1A  is a perspective view of cylindrical coordinate system  80  demonstrating spatial terminology used in the present application. The present invention is at least partially described within the context of a cylindrical coordinate system. System  80  has a longitudinal axis  81 , used as the reference for the directional and spatial terms that follow. The adjectives “axial,” “radial,” and “circumferential” are with respect to an orientation parallel to axis  81 , radius  82  (which is orthogonal to axis  81 ), and circumference  83 , respectively. The adjectives “axial,” “radial” and “circumferential” also are regarding orientation parallel to respective planes. To clarify the disposition of the various planes, objects  84 ,  85 , and  86  are used. Surface  87  of object  84  forms an axial plane. That is, axis  81  forms a line along the surface. Surface  88  of object  85  forms a radial plane. That is, radius  82  forms a line along the surface. Surface  89  of object  86  forms a circumferential plane. That is, circumference  83  forms a line along the surface. As a further example, axial movement or disposition is parallel to axis  81 , radial movement or disposition is parallel to radius  82 , and circumferential movement or disposition is parallel to circumference  83 . Rotation is with respect to axis  81 . 
         [0019]    The adverbs “axially,” “radially,” and “circumferentially” are with respect to an orientation parallel to axis  81 , radius  82 , or circumference  83 , respectively. The adverbs “axially,” “radially,” and “circumferentially” refer to an orientation parallel to respective planes. 
         [0020]      FIG. 1B  is a perspective view of object  90  in cylindrical coordinate system  80  of  FIG. 1A  demonstrating spatial terminology used in the present application. Cylindrical object  90  is representative of a cylindrical object in a cylindrical coordinate system and is not intended to limit the present invention in any manner. Object  90  includes axial surface  91 , radial surface  92 , and circumferential surface  93 . Surface  91  is part of an axial plane, surface  92  is part of a radial plane, and surface  93  is part of a circumferential plane. 
         [0021]    The following description is made with reference to  FIG. 2 .  FIG. 2  is a cross-section view of a fastener positioning device for a die block, according to an example aspect of the invention. Fastener positioning device  10  may be assembled in a die block (not shown) for a stamping press (not shown). Fastener positioning device  10  includes chute portion  12  attached to a fastener tube (not shown). The fastener tube works with a synchronizing mechanism that transmits individual fasteners through the tube as the press operates. In some example embodiments of the invention, the fastener tube transmits studs  13  or nuts (not shown). The synchronizing mechanism controls timing such that a single stud  13  is correctly oriented and introduced to the positioning device  10  between strokes of the stamping press. 
         [0022]    Stud  13  is positioned as described supra before being installed into a plate (not shown) by a die punch (not shown). Chute portion  12  includes stud tube connection portion  14 , retaining portion  16  held by pin  18  in block  20 , and angled section  22 . Angled section  22  is aligned with angled hole  24  in block  20 . Angled hole  24  connects angled section  22  to punch tube  26 , thereby guiding stud  13  into punch tube  26 . Punch tube  26  includes axis  28 . In an example embodiment of the invention, the fastener is gravity-fed through chute portion  12  into punch tube  26 . 
         [0023]    The following description is made with reference to  FIG. 3 .  FIG. 3  is a detail view of encircled region  3  in  FIG. 2 . Stud  13  is axially positioned in punch tube  26  by retainers  32  disposed in apertures  34 . In the embodiment shown, retainers  32  are balls, but other configurations of retainers  32  are possible. For example, retainers  32  may include a block with a tapered end. Apertures  34  extend radially out from tube  26 . 
         [0024]    Retainers  32  are located radially inward of groove  36 . In an example embodiment of the invention, diameter  35  of recesses  34  is not constant through block  20  and prevents balls  32  from falling into punch tube  26 . Aperture  34  comprises diameter  33  proximate punch tube  26  and diameter  35  radially outside of diameter  33 . Diameter  35  is larger than diameter  33 . In an example embodiment of the invention, aperture  34  tapers radially inward. In one embodiment, diameter  35  is constant up to edge  39  which has diameter  33 . 
         [0025]    Resilient ring  37  is positioned in groove  36 . Ring  37  may be an O-ring made of rubber or another elastic material, or a circularly-formed coil spring, for example. Ring  37  radially contracts balls  32  against edge  39  of recess  34  proximate stud shaft  38 . That is, ring  37  urges retainer  32  towards axis  28 . Edge  39  may be a rim or ledge for restricting motion of balls  32  towards axis  28 . Balls  32  are radially positioned on diameter  41  slightly larger than diameter  42  of stud shaft  38  so that stud  13  easily slides into position between balls  32 . Stud head  40  axially positions stud  13  in relation to balls  32  in punch tube  26 . That is, diameter  44  of stud head  40  is larger than diameter  41 , and contact between balls  32  and stud head  40  controls axial position of stud  13  in punch tube  26 . That is, a radial surface of stud head  40  rests on retainers  32 . 
         [0026]    The following description is made with reference to  FIG. 4 .  FIG. 4  is a detail view of encircled region  3  in  FIG. 2  showing an alternative embodiment of the invention. Nut  113  is axially positioned in punch tube  26  by retainers  32  disposed in apertures  34 . The configuration of retainers  32 , apertures  34  and ring  37  described supra applies to this embodiment as well. 
         [0027]    Balls  32  are radially positioned on diameter  41  slightly larger than diameter  142  of nut installation ring  138  so that nut  113  easily slides into position between balls  32 . Nut base  140  axially positions nut  113  in relation to balls  32  in punch tube  26 . That is, diameter  144  of nut base  140  is larger than diameter  41 , and contact between balls  32  and nut base  140  controls axial position of nut  113  in punch tube  26 . That is, nut base  140  rests on retainers  32 . 
         [0028]    The following description is made with reference to  FIG. 5 .  FIG. 5  is a partial cross section view of a die block with a fastener positioning device, according to an example aspect of the invention. Fastener positioning device  10  may include stud insertion punch  27 . Punch tube  26  is disposed perpendicular to plate  25  so that stud insertion punch  27  moves along punch tube axis  28 , parallel to stud axis  30 , when displaced in direction  29  by the stroke of the stamping press (not shown). Stud  13  is inserted into plate  25  by punch  27  traveling along punch tube axis  30 . When head  31  of punch  27  contacts head  40  of stud  13 , head  40  is pushed in direction  29  displacing retainers  32 . That is, axial force on head  40  radially displaces the retainers and resilient ring  37  so that stud  13  travels through tube  26  towards plate  25 . The tube aligns the stud with hole  23  in plate  25  so that additional force acting on punch  27  installs stud  13  into plate hole  23 . 
         [0029]    After installation of stud  13  into plate hole  23 , punch  27  is retracted in direction  46 , opposite direction  29 . Once punch  27  is retracted past retainers  32 , ring  37  urges retainers into contact with edge  39  as described supra. Once punch  27  is retracted past angled hole  24 , another stud  13  is introduced through chute portion  12  into positioning device  10 . Punch  27  is then moved in direction  29  to install new stud  13  into new plate  25 . 
         [0030]    Although fastener positioning device  10  is shown with a particular number of retainers  32 , device  10  may include other numbers of balls or retainers. Generally, at least three retainers are preferred to properly position stud  13  in the tube. 
         [0031]    Of course, changes and modifications to the above examples of the invention should be readily apparent to those having ordinary skill in the art, without departing from the spirit or scope of the invention as claimed. Although the invention is described by reference to specific preferred and/or example embodiments, it is clear that variations can be made without departing from the scope or spirit of the invention as claimed.