Patent Publication Number: US-8534653-B2

Title: Method and fixture for handling and processing die components

Description:
This is a divisional of application Ser. No. 11/222,461, filed Sep. 8, 2005. 
    
    
     BACKGROUND OF THE INVENTION 
     Dies utilized for fabricating sheet metal parts and the like typically include a die set having a pair of die shoes (e.g., flat metal plates) that are movably interconnected by posts and bushings that provide for movement of the die shoes towards and away from one another, and align and position the die shoes relative to one another. A variety of punches, die steels and the like are mounted to the die shoes for forming parts from sheet metal as it is fed into the die. A number of openings are typically machined into the die shoe for mounting of the die steel and other such components, and also to provide clearance for slugs that are punched from the sheet metal and pass through openings in the lower die shoe during the forming process. 
     Dies are often provided with parallels for mounting the die shoes to a press. In general, parallels are elongated heavy steel members with opposite edge surfaces that are machined to parallel so the parallel can position and provide support for the die in the press. The parallels typically include a plurality of threaded openings that receive threaded fasteners for securing the parallels to the die shoes. The die shoes may also include slots or openings at end portions of the parallels to provide for securing the parallel to the press. Depending upon the requirements of a particular die design, parallels may be positioned adjacent or across a slug clearance opening in the die shoe, such that clearance must be machined in the parallel to provide for proper exit of the slugs. Due to the wide variation in the size and configuration of dies, parallels are typically custom made for a particular die. Parallels are commonly rough cut from large plates of hot roll steel using a flame cutter. The rough cut parallels were then individually machined utilizing conventional manual workpiece setup and positioning methods. As a result of the time consuming manual setup and positioning, such machining methods can be costly due to the amount of labor and machine time used. 
     Accordingly, a way to reduce the setup and machining time would be desirable. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a method and fixture for handling and processing die components. One aspect of the present invention comprises use of a fixture for machine tools including a base member and first and second workpiece support units that are movably connected to the base member, the first and second workpiece units defining a space therebetween. The fixture further includes a drive assembly that is operably connected to the first and second workpiece support units. The drive assembly is operable to move the first and second workpiece support units towards one another and away from one another. The first and second workpiece support units each include a wedge member extending toward the space between the first and second workpiece support units. The wedge members include opposed engagement surfaces that taper towards one another for engagement of slots in a workpiece, i.e. a die component. The first and second workpiece support units further include a clamp having a pair of movable jaw members positioned adjacent the wedge member for clamping a workpiece as it engages the wedge members. 
     In another aspect of the invention, die component steel plates are provided with flame cut die processing features such as the aforesaid processing slots, notches and apertures, preferably at the time the component is flame cut from large plates of hot roll steel, which have nothing to do with the ultimate functionality of the die, but rather are made to facilitate handling, locating and/or holding the plate or items to be mounted on the plate during the process of die manufacture. By flame cutting such processing features into the hot roll steel plate when it is flame cut, the expense of tedious positioning, clamping and possibly even subsequent machining for processing purposes only is eliminated. 
     Another aspect of the present invention comprises use of a fixture for machine tools including a base member and first and second workpiece support units that are movably connected to the base member for movement towards and away from each other. Each workpiece support unit includes a unit base structure and a wedge member that is rotatably mounted to the unit base structure for rotating a workpiece supported on the wedge members between the first and second workpiece support units. The fixture further includes a drive assembly operably connected to the first and second workpiece support units and simultaneously moving the first and second workpiece support units towards and away from each other. 
     Another aspect of the present invention comprises use of a fixture for machine tools including a base member and first and second workpiece support units mounted to the base member. Each workpiece support unit includes a unit base structure and an attachment structure rotatably mounted to the base structure. Each attachment structure is configured to hold a workpiece for rotation in the fixture. Each workpiece support unit also includes an indexing device that selectively retains the attachment structure at a selected one of a plurality of predetermined angular positions relative to the unit base structure. The fixture further includes a mechanical drive assembly operably interconnecting the attachment structures. The mechanical drive assembly simultaneously moves the attachment structures towards and away from one another. 
     These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially schematic elevational view of a machine tool and fixture according to one aspect of the present invention; 
         FIG. 2  is a partially schematic perspective view of the machine tool and fixture of  FIG. 1 ; 
         FIG. 3  is a perspective view of a workpiece support unit of the fixture of  FIG. 1 ; and 
         FIG. 4  is a perspective view of a workpiece support unit of the fixture of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . However, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     With reference to  FIGS. 1 and 2 , a fixture  1  according to one aspect of the present invention may be mounted to a machine tool  2  to support a workpiece such as a parallel during machining operations. In the illustrated example, the machine tool  2  comprises a milling machine of a known type including a bed  5 , vertical structure  6 , and a head  7  to which a variety of cutters  4 , drill bits, reamers, or the like may be attached for machining operations. In the illustrated example, the machine tool  2  is a CNC machine having a computer control system to control the machining operations. 
     Fixture  1  includes first and second workpiece support units  12  and  13 , respectively, that securely hold and position a workpiece such as a parallel  3  during machining operations. As discussed in more detail below, workpiece support units  12  and  13  include wedge members  42  that engage slots or notches  90  that are pre-formed in the opposite ends  91 ,  92  of a rough-cut parallel  3 . Workpiece support units  12 ,  13  also include clamps  43  with jaws  44  that clamp onto opposite side surfaces  34  of parallel  3 . The workpiece support units  12  and  13  provide for rotation of the parallel  3  about a horizontal axis without disengaging wedge members  42  and clamps  43 , such that the position of parallel  3  relative to milling machine  2  remains known, and time-consuming manual setup and repositioning of parallel  3  is not required. 
     The fixture  1  includes a base  10  that is secured to the bed  5  utilizing a plurality of support blocks  11  and conventional “strap” clamps (not shown) or the like. In general, the fixture  1  may be secured to a machine tool in any suitable manner, depending upon the particular application. Also, it will be understood that the fixture  1  may be utilized with a wide variety of known machine tools. The CNC milling machine  2  is illustrated in a partially schematic manner to facilitate understanding of the use of fixture  1 , but the CNC milling machine  2  is not, per se, a novel part of the present invention. The fixture  1  includes a first workpiece support unit  12  and a second workpiece support unit  13 . The first and second workpiece support units  12  and  13 , respectively, are slidably mounted to the base  10  via linear guides  14  comprising a plurality of rails  15  that are secured to the base, and pillow or slide blocks  16 . A drive assembly  20  includes an elongated threaded member  21  extending between the first and second workpiece support units  12  and  13 , respectively. The workpiece support units  12  and  13  each include a threaded member  22  threadably engaging the elongated threaded member  21 . The threads on the elongated thread member  21  and threaded members  22  is configured such that rotation of elongated threaded member  21  in a given direction simultaneously moves the first and second support units  12  and  13 , respectively, towards and away from each other. A handle  23  is rotatably mounted to the fixture, and includes a gear mechanism (not shown) or the like of a known type that causes the elongated threaded member  21  to rotate upon rotation of handle  23 . Due to the simultaneous movement of workpiece support units  12  and  13 , a parallel  3  or other workpiece is automatically centered in fixture  1  when wedge members  42  are shifted into engagement with slots  90  upon rotation of handle  23  when parallel  3  is loaded into fixture  1 . 
     In addition to wedge members  42  and clamps  43 , fixture  1  also includes a plurality of brackets  31  that may be utilized to further support a parallel  3  in fixture  1 . Brackets  31  are movably mounted to the base  10  via guides such as transverse rails  32 . A handle  33  is rotatably mounted to the base  10 , and is operably connected to the brackets  31  by a drive assembly (not shown) of a known type that is similar to the drive assembly  20  described in more detail above. Rotation of handle  33  causes the brackets  31  to simultaneously move towards and away from each other. The brackets  31  can be clamped to the sides  34  of a workpiece  3  to provide additional support if necessary to prevent vibration or the like during the machining process. Each bracket  31  includes an upwardly extending bracket member  35  that is pivotably mounted to a base bracket member  36  via a pin  37 . The upper bracket member  35  can be pivoted to a lowered position L as shown in  FIGS. 1 and 2  to facilitate loading of a workpiece  3  in the fixture  1 . Also, the upper bracket members  35  may be positioned in the lower position L if extra support is not required during the machining of a particular workpiece. Alternately, the upper bracket members  31  may be pivoted to the upper position U and utilized to clamp a workpiece  3  as described above. 
     With further reference to  FIGS. 3 and 4 , the workpiece support units  12 ,  13  each include a unit base structure  40 , and a workpiece support accessory  30  including a wedge member  42  and clamp  43 . Workpiece support accessory  30  is rotatably mounted to the unit base structure  40  via a shaft  41  or the like. The workpiece support units  12  and  13  include a block  77  that is secured to a plate  17 , and pillow blocks  16  are, in turn, secured to the plate  17 . 
     Wedge members  42  include opposed tapered surfaces  45  and  46  that extend towards one another adjacent the end  47  of wedge members  42 . The jaws  44  of clamp  43  include outer ends  48  and clamping surfaces  49  adjacent the outer ends  48  that extend inwardly, forming a smooth radius. The radiused surface portions  49  ensure that the jaws  44  securely clamp a workpiece positioned in the workpiece support accessory, despite variations in the thicknesses of different workpieces. Inner ends  50  of jaws  44  are pivotably connected to plates  51  and  52  via carriage bolts  54 , pins or the like. A threaded rod  60  extends through clearance openings  61  in jaws  43 , and threadably engages pins  62 . Threaded rod  60  passes through a clearance opening or bushing  63  in wedge member  42 . In the illustrated example, the jaws  44  include a main jaw member  64  and a plate member  65  that closes off clearance openings  61  in main jaw members  64 . Threaded rod  60  includes an end  66  having flat surfaces or the like to thereby enable a user to rotate the threaded rod  60  to draw the jaws  44  towards and away from one another utilizing a wrench or the like. The plates  51  and  52  are secured to the shaft  41 , and the wedge member  42  is also secured to the shaft  41 , such that the clamp  43  and wedge member  42  can be simultaneously rotated together relative to the unit base structure  40  to rotate a parallel  3 . A retainer plate  55  includes a pair of elongated slots  56  that receive threaded fasteners  57 . The end portion  58  of retainer plate  55  can be positioned to overlap the plate  51 . The threaded fastener  57  can then be tightened, thereby locking the plate  51  in a horizontal position, with wedge member  42  in the position illustrated in  FIGS. 3 and 4 . The retainer plate  55  also retains the jaws  44  of clamp  43  in the position illustrated in  FIGS. 3 and 4 . 
     The first and second workpiece support units  12  and  13  also include an indexing mechanism  70  ( FIGS. 3 ,  4 ). The indexing mechanism  70  is utilized to selectively lock the workpiece support accessory  30  at a preselected one of a plurality of predetermined angular positions for machining angled clearance notches  98  ( FIG. 1 ) or the like in parallel  3 . Indexing mechanism  70  includes an index wheel  71  that is fixed to the shaft  41  via a key or the like (not shown) that engages key way  72  in shaft  41 , and a corresponding key way (not shown) in indexing wheel  71 . The end portion  73  of shaft  41  is threaded, and a threaded fastener  74  is threadably received on the shaft  41  to thereby retain the index wheel  71 . The indexing wheel  71  includes a plurality of openings  75  that extend around the indexing wheel  71  in a circular pattern. A pair of pins  76  are slidably mounted in a block  77  of unit base structure  40  adjacent opposite sides  88 ,  89  of block  77 . Pins  76  are operably connected to handles  78  that are received within L-shaped openings  79  on the opposite sides  88  and  89  of block  77 . Handles  78  can be shifted in the direction of the arrow “A” ( FIG. 3 ) to retract pins  76  from an opening  75  in index wheel  71 . Handles  78  and pins  76  are biased by a spring or the like (not shown) into the engaged position (i.e., the direction opposite arrow “A”). Handles  78  can be shifted in the direction of the arrow “B” into the end  80  of L-shaped slots  79  to thereby retain the pins  76  in the retracted position for rotation of index wheel  71  and the workpiece support accessory  30 . The openings  75  in index wheel  71  are preferably spaced at equal angular intervals to thereby position the workpiece support accessory  30  and the workpiece  3  at a known angular position. In the illustrated example, the openings  75  are positioned at 22.5° intervals relative to one another. As discussed above, retainer plate  55  may be utilized to retain the wedge member  42  and clamp  43  in the horizontal position. If the workpiece  3  is to be rotated in fixture  1 , the fasteners  57  are loosened, and the retainer plate  55  is shifted in the direction of the arrow “C” ( FIG. 3 ) such that the end portion  58  of plate  55  does not overlap plate  51 , thereby permitting rotation of wedge member  42  and clamp  43 . The indexing device  70  also includes a retaining clamp  81  having a base portion  82  and a pair of C-shaped arms  83  that extend upwardly around the outer peripheral surface  84  of index wheel  71 . A threaded fastener  85  extends through the end portions  86  of C-shaped arms  83 . The threaded fastener  85  can be loosened to permit rotation of index wheel  71  to the desired position. The pin  76  can then be engaged with the selected opening  75  utilizing handles  78 . The threaded fastener  85  can then be tightened to thereby clamp onto the indexing wheel  71 . The retaining clamp  81  is secured to the block  77  via threaded fasteners  87  or the like, such that the retaining clamp  81  prevents rotation of index wheel  71  relative to the block  77  when threaded fastener  85  is tightened. 
     With reference back to  FIG. 2 , in use a workpiece such as a parallel  3  is loaded into the fixture  1  prior to machining. The parallel  3  includes notches  90  at the opposite ends  91  and  92  of parallel  3 . The parallel  3  may be made from hot roll steel or the like, and the parallel  3  is initially rough cut with a flame cutter or the like from a large plate of steel. The notches  90  are cut into the parallel  3  at the time the parallel  3  is cut from a plate of steel, so the rough-cut parallel can be secured in fixture  1  without additional machining. The flame cutting process produces relatively rough and imprecise end surfaces  93 , and upper and lower surfaces  94  and  95 . Also, the surfaces forming notches  90  are also relatively rough and imprecise as a result of the flame cutting process. 
     The parallel  3  is initially positioned between the first and second workpiece support units  12  and  13 , respectively. The handle  23  is then rotated to draw the workpiece support units  12  and  13  towards one another. The parallel  3  is positioned with notches  90  in alignment with wedge members  42 , and wedge members  42  enter the notches  90  as the workpiece support units  12  and  13  are drawn together. The tapered surfaces  45  and  46  of wedge members  42  engage notches  90 , typically at corners  96 , to thereby support and center the parallel  3 . The clamps  30  are then tightened utilizing a wrench or the like to rotate the threaded members  60 . In this way, the parallel  3  is rigidly secured in the fixture  1 . Because workpiece support units  12  and  13  simultaneously move towards one another at the same rate, the parallel  3  is automatically centered relative to opposite ends  91  and  92  of parallel  3  in fixture  1  as wedge members  42  engage notches  90 . Also, jaws  44  contact opposite sides  34  of parallel  3  and thereby center parallel  3  in fixture  1  relative to sides  34 . 
     If required, the upper bracket members  35  may be positioned in the upright position “U”, and handle  33  may then be rotated to clamp onto the opposite sides  34  of parallel  3  to further support the parallel  3  in fixture  1 . The surface  94  of parallel  3  may then be machined flat, and a number of features such as threaded openings  97  may also be machined. The retainer plates  55  and clamp  81  may then be loosened, and handles  78  are also shifted to retract the retainer pins  76  from index wheels  71  to rotate the parallel  3  about axis “H” to a desired angular position. One or more clearance notches or ramps  98  may then be machined at an angle in the parallel  3  to provide for exit of slugs and the like, or to provide clearance for other components or the like. 
     As discussed above, the wedge members  42  and clamps  43  center the parallel  3  on the fixture  1 , such that the position and orientation of the various openings  97 , clearance notches  98 , and/or other machined features are precisely located relative to one another. After machining the upper surface  94 , the parallel  3  can be rotated 180° in fixture  1 , and the surface  95  may then be machined parallel to the surface  94 . If additional features need to be machined into surface  95 , such features can be accurately positioned relative to each other, and relative to the surface  94  and other machined features associated with surface  94 . 
     The fixture  1  does not require the time-consuming manual setup procedures associated with conventional machining operations. The wedges  42  and clamps  43  quickly center a workpiece in the fixture  1 , and securely hold the workpiece for machining. Because the workpiece does not move relative to the wedges  42  and clamps  43 , the workpiece can be rotated to provide for accurate machining on opposite sides of the workpiece without manually measuring and locating the workpiece. 
     In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.