Abstract:
A worktable apparatus for a machine tool, such as a CNC punch press, a laser equipped machine tool or plasma torch equipped machine tool, which processes a metal sheet or plate workpiece. The worktable apparatus serves a dual function as (a) a worktable that supports a workpiece during processing by a machine tool and as (b) an unloading station for unloading a workpiece or a skeletal remnant produced by the machine tool. The machine tool has a set of workclamps, which move under CNC control along at least one of the numerically controlled axes, grip the workpiece and carry it through the machine for processing. Located on one side of the machine tool, the worktable apparatus has a surface adapted to allow the workpiece to ride smoothly under the motive power of the workclamps. In one embodiment, the worktable apparatus is made up of two roller sets supported such that one long edge of each is fixed to a frame, and the other edge is normally supported in horizontal orientation creating a gap between the roller sets. When a workpiece or a skeletal remnant is rolled into position on the worktable apparatus and the CNC initiates the worktable apparatus to open, controlled actuators, such as cylinders, cause the center edges of the two roller sets to drop away, allowing the workpiece or skeletal remnant to fall freely from its supported position on the worktable apparatus to an unloaded position below.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]    This patent application claims the benefit of U. S. provisional patent application No. 60/283,312 , filed Apr. 12, 2001. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates generally to machine tools, and more particularly to a worktable apparatus that serves a dual function as (a) a worktable that supports a workpiece during processing by a machine tool and as (b) an unloading station for unloading a workpiece or skeletal remnant produced by the machine tool.  
         BACKGROUND OF THE INVENTION  
         [0003]    There is a continuing effort within the metal fabrication industry to automate and improve CNC punch presses to reduce manufacturing cost, improve productivity, and to reduce the setup time and general workload of the operator of the machine. CNC punch presses have been developed with automatic loading and unloading systems. Some CNC punch presses are equipped with a plasma torch or a laser cutting attachment. Such machines process nests of parts. The plasma torch or laser cutting attachment is used to cut large holes that exceed the maximum punch size available or exceed the punching capacity of the press and to cut the outer boundary of parts. Some embodiments of plasma cutting machines and laser cutting machines, not having a punching apparatus, also process nested parts.  
           [0004]    A nest is a group of parts of a common material type and thickness, grouped in a common sheet or plate. Processing parts in this manner makes it possible to use a common sheet size for production, reduces setup time, and reduces scrap. Software for nesting parts and creating part programs of nests for controlling laser equipped or plasma torch equipped CNC punch presses has been commercially available for several years.  
           [0005]    Processing nested parts on a CNC punch press having a plasma torch or a laser cutting attachment typically produces a skeletal remnant that is scrap material. Various means have been employed to automatically remove the remnant from the CNC punch press. All means that the inventors are aware of have employed a transfer apparatus to grip the remnant in some manner and pull it off the machine or transfer it to a separate device for stacking on a pallet or on the floor. Several embodiments of such apparatus employ a dedicated transfer mechanism that pulls the remnant from the machine tool worktable. Another form employs a robotic loading/unloading device to grip the skeletal remnant with dedicated clamps that swing into position from a load platen and transfer it to a separate scrap table for stacking. While such devices have been functional, they have inherent disadvantages.  
           [0006]    The cost of a dedicated transfer mechanism is a disadvantage. A dedicated transfer mechanism takes up valuable floor space. In some cases there is limited floor space available. A separated scrap table for stacking remnants also requires floor space. There can be “lost time” associated with transferring the remnant. Skeletal remnants by nature are inherently weak and can be difficult to handle.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    It is an objective of the invention to quickly remove skeletal remnants from a CNC machine tool and to minimize the cost of equipment to do so.  
           [0008]    It is another objective to minimize dedicated floor space for stacking skeletal remnants at the machine tool.  
           [0009]    It is a further objective to remove a skeletal remnant from a CNC machine tool worktable without employment of a dedicated transfer mechanism.  
           [0010]    It is another objective of the invention to provide a worktable that supports a workpiece during processing thereof by a machine tool and that stacks the remaining skeletal remnant thereof proximate to the floor.  
           [0011]    It is a further objective of the invention to provide a worktable that can be adapted with different workpiece supporting means that supports a workpiece during processing thereof by a machine tool and that can quickly unload the remaining skeletal remnant thereof.  
           [0012]    It is yet a further objective of the of the invention to provide a worktable that can reside on the machine loading side of a machine tool, can support a workpiece during the loading function, can support the workpiece during processing of the workpiece by the machine tool, and can quickly unload the remaining skeletal remnant thereof from the machine tool.  
           [0013]    Finally, it is another objective of the invention to provide a worktable that can reside on the side opposite of the machine loading side of a machine tool, that can support a workpiece during processing of the workpiece by the machine tool, and can quickly unload the remaining skeletal remnant thereof from the machine tool.  
           [0014]    Other features and advantages of the invention will be readily apparent from the following description of a preferred embodiment thereof, taken in conjunction with the accompanying drawings, although variation and modifications may be effected without departing from the scope and spirit of the novel concepts of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:  
         [0016]    [0016]FIG. 1 is a plan view of a CNC punch press employing a preferred embodiment of the invention.  
         [0017]    [0017]FIG. 2 is a cross sectional view, generally taken through  2 - 2  of FIG. 1, and showing open workclamps, a remnant on the worktable and the worktable in a workpiece supporting position.  
         [0018]    [0018]FIG. 3 is the view of FIG. 2 except the worktable is shown in a remnant unloading position with a remnant shown falling to a stack of remnants.  
         [0019]    [0019]FIG. 4 is a front elevation view of the worktable of FIG. 1.  
         [0020]    [0020]FIG. 5 is an end view, taken generally from  5 - 5  of FIG. 1, showing an alternate embodiment of the invention in which remnants can be removed through the end of the worktable.  
         [0021]    [0021]FIG. 6 is a plan view of a CNC punch press having an alternate embodiment of the invention.  
         [0022]    [0022]FIG. 7 is cross sectional view of a barrel roller than can be adapted to the worktable.  
         [0023]    [0023]FIG. 8 is a plan view of an omni-wheel that can be adapted to the worktable.  
         [0024]    [0024]FIG. 9 is a plan view of a CNC punch adapted with a preferred embodiment of the invention and adapted with a workpiece loader that is also capable of unloading large parts. 
     
    
       [0025]    While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    [0026]FIG. 1 is a plan view of a CNC punch press illustrating a preferred embodiment of the invention. FIG. 1 shows a machine tool  1 , a CNC punch press having a loading apparatus  2 . A stack of material  3  is staged proximate to the loading apparatus  2 . The stack of material  3  is preferably flat, rectangular metal sheets and/or plates. The loading apparatus  2  is adapted to lift a single sheet  3 ′ from the stack of material  3 . The single sheet  3 ′ is transferred over a worktable  4 , lowered to the surface of worktable  4  then moved against registration surfaces  5  and  5 ′ of workclamps  6  and  6 ′. The worktable  4  is adapted with a plurality of ball transfers  7  such that the single sheet  3 ′ can be rolled on the worktable  4  by the loading apparatus  2  to load the sheet into the workclamps  6  and  6 ′. The loaded single sheet  3 ′ is called a workpiece.  
         [0027]    Alternate embodiments of the machine tool  1  can be a CNC punching machine without a thermal cutting attachment or can be a thermal cutting machine such as a plasma torch or a laser not having a punching tool. The reference to the machine tool  1  is intended to apply inclusively to such machines unless the context clearly indicates otherwise.  
         [0028]    In the preferred embodiment of the invention, movement of the workpiece is in only one direction, along the X-axis. Movement of the workhead effects movement in the Y-axis. There are many machine configurations in which the workclamps move in both the X and Y directions and the workhead remains stationary. Some configurations have stationary worktables adapted with spring loaded ball transfer bearings or brushes and an X-axis carrying rail translatable in the Y-axis to move the workpiece over the stationary worktables. The workclamps are mounted on a small table translatable in the X-axis that is carried on the translatable X-axis carrying rail. The invention is fully applicable to such machines. As will be apparent to one skilled in the art, after reading the following disclosure, the workclamps can be brought to a Y coordinate associated with “unload” then indexed in the X direction to carry the skeleton remnant over the drop leaf table before releasing it.  
         [0029]    Alternate embodiments of machine tool  1  can be adapted with the thermal cutting attachment on the side opposite that shown or with the loading apparatus on the side opposite that shown. The invention is intended to apply inclusively to such embodiments unless the context clearly indicates otherwise.  
         [0030]    The worktable apparatus is also adaptable to CNC punching machine configurations that are not adapted with an automatic loader. In such form, the worktable apparatus provides an inexpensive means to quickly remove a skeletal remnant from the machine tool. In rare instances the part produced by such a machine tool constitutes the entire workpiece  3 ′. In such instances the worktable apparatus can be utilized to unload and stack the part.  
         [0031]    CNC punch press  1  has an X-axis  8  defined by a X rail  8 ′, supported by a bracket  9  and pedestals  10  and  10 ′, and carrying a translatable table  11 . The translatable table  11  is driven by a servomotor and a ballscrew that are not shown and carries workclamps  6  and  6 ′, for gripping the workpiece  3 ′, and a plurality of punching tool sets  12 . A press frame  13  carrying a translatable workhead  14  that is adapted for punching and is mounted to a mounting plate  15  defines the Y-axis. A translatable die support, not shown, is located below mounting plate  15 . The workhead  14  is positioned along the Y-axis by a servomotor  16  connected by a coupling  17  to a ballscrew  18 .  
         [0032]    Proximate in front of the workhead  14  are two reposition cylinders  19  mounted on the bottom surface of the mounting plate  15 . The function of the reposition cylinders  19  is to clamp the workpiece  3 ′ processed by machine tool  1  during workclamp reposition cycles. The workpiece is clamped by reposition cylinders  19  such that it will not move when workclamps  6  and  6 ′ are opened and repositioned relative to the workpiece  3 ′.  
         [0033]    Connected to the left side the mounting plate  15  is a plasma torch  20  for cutting large holes and the outer boundary of parts from workpiece  3 ′. Below and to the immediate left of torch  20  is a drop leaf table apparatus  21  for removal of small parts after they have been cut from workpiece  3 ′. The drop leaf table apparatus  21  is adapted with ball transfers  7  for supporting workpiece  3 ′ as it is processed.  
         [0034]    An electrical cabinet  22  houses the CNC and electrical controls and a operator station  23  provides the man/machine interface for machine tool  1 .  
         [0035]    During operation of machine tool  1 , the workpiece  3 ′ is gripped by the workclamps  6  and  6 ′ and moved and positioned under CNC control along the X-axis  8  while the workhead  14  and the die support are moved and positioned under CNC control along the Y-axis. The workpiece  3 ′ is positioned and tools are selected according to a part program processed by the CNC. At commanded positions the CNC cycles the workhead  14  to punch a hole in the workpiece  3 ′. After all holes have been punched, the CNC in like manner positions the plasma torch  20  to commanded positions, lowers the plasma torch  20  to the workpiece  3 ′, ignites the plasma torch  20  then coordinates the velocity and motion of the X and Y axes to move the plasma torch  20  along a described path to create a hole or to cut a part from workpiece  3 ′. Small parts cut from the workpiece  3 ′ are unloaded via the drop leaf table  21 . Large parts are removed manually or with the assist of a hoist or crane. When all parts have been removed from the workpiece  3 ′, the CNC via the workclamps  6  and  6 ′, positions the skeletal remnant on a worktable  24  to be unloaded.  
         [0036]    The worktable  24 , on the right side of the frame  13 , is adapted with two sets of conveyor rollers  27  forming two drop leaf tables  33  which support the workpiece  3 ′ while it is processed by the CNC punch press  1 . The conveyor rollers are a workpiece supporting means. The roller sets  27  are separated by a gap large enough that the roller sets  27  may be controllably dropped (opened) to create a large opening through which a skeletal remnant can fall. FIG. 1 shows a relatively wide gap  27 ′ almost as wide as the roller sets  27 . This arrangement provides adequate support for the workpiece  3 ′ and a space  150 , FIG. 3, adequate for stacking remnants without causing interference with motion of the drop leaf tables  33 . Other gap configurations may be used as long as the roller sets are capable of adequately supporting the workpiece  3 ′ and of moving between the closed workpiece supporting position and the open unloading position without interference.  
         [0037]    The worktable  24 , also called a worktable apparatus, a scrap table or a scrap table apparatus, is shown in a preferred form and is adapted to unload skeletal remnants  36  from machine tool  1  such that they fall through the scrap table  24  and are stacked on blocks  28  resting on or proximate the floor. Scrap table  24  can be adapted such that a stack of unloaded skeletal remnants  37  can be removed through the front side, shown by arrow  29  or through the end, shown by arrow  30 . Scrap table  24  is adaptable to other CNC punching machine configurations. In such adaptations, the scrap table  24  can be configured such that unloaded remnants are removed from below the scrap table  24  through any side or end of the scrap table  24  that is not obstructed by the machine tool  1  or an associated apparatus.  
         [0038]    The worktable  24  has a frame  31  carrying cylinders  32  adapted to pivot drop leaf tables  33  via pivot shafts  34  about bearings  35  between positions horizontal, FIG. 2, such that drop leaf tables can support a workpiece  3 ′ or a skeletal remnant  36  and vertical, FIG. 3, such that the skeletal remnant  36  is dropped through the worktable  24  to stack  37  on blocks  28  resting on the floor. In a preferred form, drop leaf tables  33  are adapted as roller conveyors having side rails  38  supporting conveyor rollers  27 . The cylinders  32  can be air, hydraulic, electric cylinders having a motor driven ballscrew apparatus, or any other suitable driving apparatus.  
         [0039]    [0039]FIG. 2 is a sectional view, taken generally through  2 - 2  of FIG. 1, except that the workclamps  6  and  6 ′ are translated along the X-rail  8 ′ to carry the workpiece  3 ′ or the skeletal remnant  36  over the drop leaf tables  33 . FIG. 2 shows an open workclamp  6 ′, a skeletal remnant  36  on the drop leaf tables  33  and the cylinders  32  in closed position. Elements common with FIG. 1 are labeled with same numbers as in FIG. 1. As best seen in FIG. 2, the side rails  38  are stiffened by a bar  39 . The side rails  38  and the bars  39  of each conveyor are connected by cross ties  40 .  
         [0040]    As best seen in FIG. 5, the side rails  38  are attached with screws  41  to a pivot bracket  42 . Pivot shafts  34  and pins  43  are attached to the pivot brackets  42 . The cap ends of cylinders  32  are clevis mounted by pins  43 ′ to clevis brackets  44 , which are attached by screws  45  to plates  46  welded to the frame  31 . Cylinder rods  47  are attached to rod eyes  48  pivotally connected to pins  43 . Switches  32 ′ mounted on cylinders  32 , FIG. 2, detect the position of the cylinder piston when cylinder rods  47  are extended providing indication that drop leaf table  33  is in closed horizontal position.  
         [0041]    As best seen in FIGS. 2 and 5, when all parts have been removed from the workpiece  3 ′, the CNC via the workclamps  6  and  6 ′, positions the skeletal remnant  36  on worktable  24  to be unloaded. The CNC commands workclamps  6  and  6 ′ to open. As best seen in FIG. 3, the CNC commands cylinders  32  to retract causing drop leaf tables  33  to pivot from a closed horizontal position to an open vertical position causing skeletal remnant  36  to pull forward, free of workclamps  6  and  6 ′, and fall through scrap table  24  to the stack  37  resting on the blocks  28  laying on the floor  49 . Best seen in FIG. 4 are the formed bars  50  at each end of the frame  31  which guide the skeletal remnant  36  as it falls to the stack  37 .  
         [0042]    The frame  31  fabricated primarily from steel angles, is supported proximate four corners by leveling screws  51  on pads  52  and bolted to floor  49  by anchor bolts  53 .  
         [0043]    [0043]FIG. 4 is a front elevation view of the worktable  24  of FIG. 1. A cable carrier  54  attached lower right side of the press frame  13  and a press frame leveling jack  55  restrict how close the worktable  24  can be mounted relative to the frame  13 . A cantilevered frame  56 , supported by a brace  57  holds two conveyor rollers  26  and comprises an extension to the worktable  24 , for supporting a workpiece, such that the worktable  24  can be mounted clear of obstructions. A valve  58  and a cabinet  59  are mounted on a plate  60  supported by a vertical frame member  61 . The valve  58  controls the cylinders  32  in response to signals from the CNC of machine tool  1 . The cabinet  59  provides means to electrically connect the valve  58  and the switches  32 ′ to the CNC.  
         [0044]    A guard  62 , FIG. 4, resides between the cantilevered frame  56  and the drop leaf tables  33  to guide the end of a workpiece  3 ′ over the connection of the rod eye  48  to the pin  43 . A deflector  63 , proximate the left end of the scrap table  24  is attached to the pivot bracket  42  to guide the workpiece  3 ′ over pivot bracket  42 . The deflector  63 , proximate the right end of the scrap table  24 , is attached to the pivot bracket  42  to guide the skeletal remnant  36  over the pivot bracket  42  in the event that the right end of the skeletal remnant  36  is inadvertently positioned beyond the pivot bracket  42 .  
         [0045]    In FIGS.  1 - 4  it is intended that the skeletal remnants stacked on blocks  28  be removed from worktable  24  through the front side, shown by arrow  29 . Referring to FIG.  4 , it is noted that the front side of frame  31  is open proximate the floor  49 . Blocks  28  are arrayed parallel to the skeletal remnant removal direction  29 . The skeletal remnant may also be referred to as unloaded material. The unloaded material could be a finished part or a skeletal remnant which would be the scrap portion of a workpiece  3 ′. The blocks  28  space the stack  37  above the floor  49  for insertion of lift truck forks to remove the stack  37 .  
         [0046]    Referring to FIGS. 2 &amp; 3, it is noted that a horizontal frame member  64  is welded between legs  65  and  65 ′. FIG. 5 is an end view, taken generally from  5 - 5  of FIG. 1, of an alternate form of the invention such that remnants can be removed through the end of the worktable  24 , as shown by reference arrow  30 , FIG. 1. It is noted in FIG. 5 that the horizontal frame member  64  is cut away between  66  and  66 ′ for removal of the remnant stack  37 . It is also noted that blocks  28  are arrayed parallel to the removal direction  30 .  
         [0047]    [0047]FIG. 6 is a plan view of a CNC punch press illustrating an alternate embodiment of the invention. Elements common with FIG. 1 are labeled with the same numbers as in FIG. 1. To avoid redundancy and for clarity, several elements common with FIG. 1 are not numbered. The loading apparatus  2  is located on the right side of the press frame  13  proximate the right end of a worktable  124  and loads a workpiece  3 ′ onto the worktable  124  and into the workclamps  6  and  6 ′. Drop leaf tables  133  and a cantilevered frame  156 , FIG. 6, are adapted with the ball transfer bearings  7  as a workpiece supporting means in lieu of conveyor rollers. The workpiece  3 ′ can be rolled on the worktable  124  by the loading apparatus  2  to load the workpiece  3 ′ into the workclamps  6  and  6 ′. Skeletal remnants  37  are removed from the worktable  124  through the front side as indicated by the arrow  29 .  
         [0048]    In a further alternate form, the drop leaf tables  133  and cantilevered extension  156  can be adapted with skate wheel conveyors as a workpiece supporting means.  
         [0049]    In another alternate form, the drop leaf tables  133  and the cantilevered extension  156  can be adapted with barrel rollers  67  as a workpiece supporting means. FIG. 7 is a sectional drawing of a single barrel roller  67  that can be adapted to the worktable  124 . The barrel roller  67  is supported by flanged bearings  68  on a shaft  69  within a housing  70 . The upper end of the housing  70  has a shoulder  71  for supporting sheet  72 , the upper surface of the drop leaf table  133  or cantilevered frame  156 . Housing  70  is sandwiched between sheet  72  and bottom plate  73  which are held together by fasteners not shown.  
         [0050]    In another alternate form, the drop leaf tables  133  and the cantilevered extension  156  can be adapted with omni-wheels  74  for a workpiece supporting means. FIG. 8 is a drawing of a single omni-wheel  74  that can be adapted to the scrap table  124  in place of the ball transfer bearings  7 . The omni-wheel  74  is adapted with eight barrel shaped rollers  75  supported by axles  76 , four on the near side of a frame  77  and four on the back side of the frame  77  indexed 45 degrees relative to the four barrel rollers  75  on the front side. The omni-wheels  74  can be mounted in a manner similar to that shown in FIG. 7.  
         [0051]    In another alternate form, the drop leaf tables  133  and the cantilevered extension  156  can be adapted with brushes in place of the ball transfer bearings  7 . Brushes are adapted such that the brush tuft is turned upward to support the workpiece being processed. Brush type material support is used to prevent scratching of the workpiece during processing.  
         [0052]    In alternate form, the worktables  24 ,  124  can be adapted with a pallet proximate the floor such that skeletal remnants are dropped through the worktable  24  or  124  to stack on a pallet. The pallet and stacked skeletal remnants are removable through a side or end of worktable  24 ,  124  for disposal of the skeletal remnants. In another alternate form, the worktable  24 ,  124  can be adapted with a conveyor proximate the floor, in place of blocks  28 , such that skeletal remnants are dropped through worktable  24 ,  124  to a conveyor that transports the skeletal remnants elsewhere for storage or disposal.  
         [0053]    [0053]FIG. 9 is a plan view of a machine tool  100  embodied with a preferred loader/unloader  101 . The loader/unloader  101  is described in a co-pending patent application of Michael A. Tomlinson, Sidney B. Schaaf, and Alfred J. Julian, application Ser. No. 09/______, descending from U.S. provisional patent application serial No. 60/283,300, filed Apr. 12, 2001, the teachings and disclosure of which are hereby incorporated in their entirety by reference thereto. Machine tool  100 , a CNC controlled punch press, is like machine tool  1  of FIG. 1 except that the punching tool sets  12  of FIG. 1 are not shown. Several items equivalent to those of FIG. 1 are identified with same numbers. Some items equivalent to those of FIG. 1 are not identified to eliminate excessive redundancy.  
         [0054]    Machine tool  100  is adapted to have punching tool sets distributed along a translatable X-axis table  11  held by holders  12 ′, also called pockets, in predetermined positions that are numbered, from left to right,  1  thru the total number of pockets on table  11 . Number tags that are too small to be seen in FIG. 9 identify the pocket positions. The pockets  12 ′ can hold either a workclamp or a punching tool set. A workclamp can be moved to a pocket previously occupied by a punching tool set and a punching tool set can be moved to a pocket previously occupied by a workclamp.  
         [0055]    Upon machine power up or after a change in machine setup the machine operator must run a machine setup program before the machine is used to produce parts. The setup program moves the X-axis table  11  carrying the workclamps  6  and  6 ′ and punching tool sets  12  such that the workclamps  6  and  6 ′ pass over a sensor that detects the pocket position numbers that hold a workclamp. The workclamp positions are stored for future use. Safety zones are then established for each workclamp to prevent collision of a workclamp with the workhead  15  or the plasma torch  20 .  
         [0056]    Proximate in front of the workhead  14  are two reposition cylinders  19  mounted on the bottom surface of mounting plate  15 . When the workclamps  6  and  6 ′ must be repositioned relative to the workpiece in process, cylinders  19  clamp the workpiece such that it will not move when the workclamps  6  and  6 ′ open.  
         [0057]    Behind the machine tool  100  is a plasma power pack  102  for operating the plasma torch  20 . A dust collector  103  collects smoke and dust from operation of the plasma torch  20 . To the immediate rear of the frame  13  is a hydraulic power unit  104  for powering the operation of features of machine tool  100 .  
         [0058]    Worktable  24  located to the right of frame  13 , FIG. 9 is a worktable  24  like that of FIGS.  1 - 4 .  
         [0059]    To the left of the machine tool  100  is a loader/unloader  101  that has a magnetic platen  105  that has a Programmable Logic Controller, PLC  106 . The CNC of machine tool  100  communicates to PLC  106  which of the magnets  107  are to be utilized and what magnetic field strength to employ. PLC  106  activates and deactivates the selected magnets and monitors their operation.  
         [0060]    To the left of the workclamp  6  is a bracket  108  attached to the stationary X-axis rail  8 ′. A photo switch  109  is mounted to the bracket  108 . The photo switch  109  is preferably the same type as a Cutler Hammer E58-30DP150-ELPB. Other similar photo switches may also be used. The function of the photo switch  109  is to find the left edge of a workpiece that has been loaded into the workclamps  6  and  6 ′. The description of how this is accomplished will follow later. The CNC has a “fixture offset” position associated with the position of the photo switch  109 . The CNC also has a “modifier” position associated with the position of the photo switch  109  such that the photo switch does not have to be installed exactly at the “fixture offset” position. The CNC adds the positive or negative “modifier” to the “fixture offset” position to determine exactly where the photo switch is installed relative to the X-axis “0”.  
         [0061]    A smart drive, not shown, such as a VLT 5000 series voltage vector control drive manufactured by Danfoss, that is programmed in statement language, positions the Z-axis of the loader/unloader  101  by operating a motor that cannot be seen. Other similar drives may also be used. The motor and associated components are named the Z-Axis because they raise and lower magnetic platen  105 . The smart drive closes the motor position loop accomplishing control of the axis independently from the CNC.  
         [0062]    The pivoting motion of the loader/unloader  101 , driven by a servomotor  110 , is named the W-axis. Preferably, the pivoting motion is controlled directly by the CNC of machine tool  100 . This control scheme is used because of availability within the CNC system of a control function allowing a commanded move to be terminated before reaching the commanded position and for the remainder of the move to be abandoned or skipped.  
         [0063]    To the left rear of the machine tool  100  is a material storage tower  111  for storage of various thickness of raw material to be processed. Material storage tower  111  has a loading side  112  and a material staging station  113 . The loading side  112  is equipped with an elevator apparatus to store and retrieve pallets of material from the storage tower. The material staging station  113  contains magnetic sheet fanners to assist separation of steel sheets. A pallet of material  3  is removed from the storage tower  111  by the elevator apparatus then moved by a pallet transfer apparatus to the material staging station  113  for loading by the loader/unloader  101  to worktable  4 , into workclamps  6  and  6 ′, against registration surfaces  5  and  5 ′, for processing by machine tool  100 .  
         [0064]    In its preferred form, the material storage tower  111  is controlled by a standalone PLC. Preferably, a smart drive, such as a VLT 5000 series voltage vector control drive manufactured by Danfoss, controls the elevator drive. Other similar drives may be used. Such a smart drive closes the motor position loop accomplishing control of the axis independently from the PLC. The PLC communicates with the smart drive. These communications request the elevator drive to position the material tower elevator to specified shelf locations. The material storage tower PLC controls the movement of pallets in and out of the shelves of the tower. The pallet transfer apparatus, which moves a pallet from the material tower elevator to the material staging position  113 , is also controlled by the PLC. The CNC of the machine tool  100  communicates with the material storage tower PLC requesting a specific action such as delivery of 0.5-inch thick material to the material staging position  113 . The PLC initiates the action and signals the CNC when that action has been accomplished.  
         [0065]    In alternate form, the CNC of the machine tool  100  controls the material storage tower  111  in place of the standalone PLC. In this embodiment the elevator drive for the material storage tower  111  remains a smart drive programmed in statement language. The CNC communicates with the smart drive. These communications cause the elevator drive to position the material tower elevator to a requested shelf. The CNC controls movement of pallets in and out of the shelves of the storage tower  111 . The pallet transfer apparatus, which moves a pallet from the material storage tower elevator to the material staging position  113  for loading, is also controlled by the CNC via input/output logic.  
         [0066]    After a pallet is positioned at the material staging position  113  the CNC communicates with the PLC  106  of the magnetic platen  105 . This communication informs PLC  106  which magnets to activate and what magnetic field strength to develop to ensure a single sheet of material is picked up. Once this transmission has been completed, the CNC initiates a load cycle. Following is a description of an example of that cycle.  
         [0067]    (1) The Z-axis of the loader/unloader  101  moves to a full up position such that magnets  107  will clear the top of X rail  8 ′.  
         [0068]    (2) The following dimensions, formulas, and parameters are given by example and not by limitation. The X-axis moves the workclamps  6  and  6 ′ to a calculated plate load position ((((“X”−1)*10.236)+7.244)+28.0) where “X” contains the tool pocket number of the second workclamp, 10.236 is the distance between tool pockets, 7.244 is the distance from the centerline of the first tool pocket to the centerline of the machine tool  100 , and 28.0 is an approximate minimum position required to assure the second workclamp, workclamp  6 ′, is in a position to clamp the workpiece  3 ′. The 28.0 position can be changed to suit installation conditions. Simultaneously, the Y-axis moves the workhead  14  and the plasma torch  20  to a safe location out of the way of the loading cycle. Simultaneously, the W axis moves over the material staging position  113  and all the magnets  107  are fully de-energized to have no attraction to metal.  
         [0069]    (3) The workclamps  6  and  6 ′ reach load position, then open.  
         [0070]    (4) The W-axis of the loader/unloader  101  reaches the staging position, and then the Z-axis of the loader/unloader  101  moves down until material  3  is contacted, then stops. A sensor apparatus  116  associated with the magnetic platen  105  indicates to the CNC “contact with material”.  
         [0071]    (5) Upon receipt of the “contact with material” signal, the CNC commands the PLC  106  to prepare to pick up a sheet of material. All other signals to the PLC  106  are off. The PLC  106  activates all previously selected magnets at specified magnetic field strength, and all other magnets to the off (fully deactivated magnetic field strength level). When the PLC  106  verifies that all magnets  107  are properly seated and energized to specified magnetic field strength, PLC  106  communicates an “ok to go” signal to the CNC.  
         [0072]    (6) Upon receipt of the “ok to go” signal, the CNC commands the smart drive of loader/unloader  101  to move the Z-axis up. At a pre-designated time, when the magnetic platen  105  is far enough away from the top of the material stack that switching all magnets to high power will not cause the magnetic platen  105  to pick up another sheet of material, the CNC commands PLC  106  to energize all magnets to fall magnetic field strength. Tentatively, the time is set to three seconds after the start of the up move. If the Z-axis reaches full up position before the magnets have been energized to full field strength, the CNC commands PLC  106  to energize all magnets to full magnetic field strength at full up position.  
         [0073]    (7) With the magnetic platen  105  at full up position, sensor apparatus  116  communicating that the sheet of material is held by the magnetic platen  105 , and PLC  106  communicating that all magnets are at full field strength, the CNC moves the loader W-axis to a position over the worktable  4  such that the rear edge of the sheet is forward of the workclamps  6  and  6 ′ then stops.  
         [0074]    (8) The CNC commands the smart drive of the loader  101  Z-axis to lower the magnetic platen  105 . Z-axis motion stops when the sensor apparatus  116  indicates the material has reached the surface of the worktable  4  or when the distance to the worktable  4  has been traveled.  
         [0075]    (9) The CNC releases locking apparatus  114  of loader  100  to allow the sheet of material to align with workclamps  6  and  6 ′ against the sensors  5  and  5 ′ and moves the loader/unloader  101  W-axis toward the open workclamps  6  and  6 ′.  
         [0076]    (10) When the sensors  5  and  5 ′ detect the sheet of material is against the registration surfaces of workclamps  6  and  6 ′, W-axis motion is halted and the workclamps are closed.  
         [0077]    (11) When the workclamps  6  and  6 ′ have closed the CNC commands PLC  106  to de-energize all magnets  107  to zero magnetic field strength to release the plate.  
         [0078]    (12) The PLC  106  communicates to the CNC that all the magnets  107  are at zero magnetic field strength then the CNC commands the smart drive of the loader/unloader  101  to move the Z-axis to the full up position. This full up position, above the worktable  4  is the standby position of the loader/unloader  101 .  
         [0079]    (13) The smart drive controlling the loader/unloader  101  Z-axis signals the CNC that the Z-axis is at the full up position, then the CNC commands the PLC  106  to energize all the magnets  107  to full strength to conserve power and the CNC initiates finding the leading edge of the workpiece  3 ′ loaded in the workclamps  6  and  6 ′.  
         [0080]    (14) The CNC moves an X-axis table  11  carrying the workclamps  6  and  6 ′ and the workpiece  3 ′ in a series of incremental moves such that the position of the left edge of the workpiece  3 ′ relative to X “0” is accurately determined by a photo sensor  109 . If the photo sensor  109  detects the workpiece  3 ′, the first of the series of moves is to the right, X minus, until the photo sensor  109  loses the workpiece  3 ′. If the photo sensor  109  does not detect the workpiece  3 ′, the first of the series of moves is to the left, X plus, until the photo sensor  109  detects the workpiece  3 ′. The CNC then reverses the direction of travel of the X-axis table  11 , reduces the move velocity and reduces the move increment to a smaller step such that the photo sensor  109  changes state. This process is repeated several times with direction changes and smaller increment steps until the location of the edge of the workpiece  3 ′ in the X-axis is accurately determined.  
         [0081]    (15) The CNC then calculates the position of the edge of the workpiece  3 ′ relative to the X-axis zero position. The CNC uses this calculated position to reposition the workclamps  6  and  6 ′ relative to the workpiece  3 ′.  
         [0082]    (16) The CNC moves the X and Y-axes to a position such that the reposition cylinders  19  can clamp the workpiece  3 ′ during repositioning of the workclamps  6  and  6 ′.  
         [0083]    (17) The CNC initiates the reposition cylinders  19  to clamp the workpiece  3 ′.  
         [0084]    (18) The CNC initiates opening workclamps  6  and  6 ′ thereby releasing the workpiece  3 ′.  
         [0085]    (19) The CNC moves the X-axis table  11  to reposition the workclamps  6  and  6 ′ such that when the workclamps  6  and  6 ′ are closed and the X-axis table  11  is moved to X “0”, the left edge of the workpiece  3 ′ will be positioned on the X centerline of the workhead  14 .  
         [0086]    (20) The CNC initiates closure of the workclamps  6  and  6 ′ to grip the workpiece  3 ′.  
         [0087]    (21) The CNC initiates the reposition cylinders  19  to retract to their full up position.  
         [0088]    (22) The workpiece  3 ′ is now fully gauged and ready for processing by the machine tool  100 .  
         [0089]    The machine tool  100  processes the workpiece  3 ′ such that all punching operations are performed; then any larger holes are cut with the plasma torch. Afterward, the plasma torch cuts individual parts from the workpiece  3 ′. Small parts are unloaded from the machine via a drop leaf table  21 . Parts too large for the drop leaf table  21  are unloaded by loader/unloader  101 .  
         [0090]    An unloading zone  115 , FIG. 9 outlines an area for unloading large parts. The unloading function of the loader/unloader  101  can stack parts on a table or on pallets or drop parts into containers located within the unloading zone  115 .  
         [0091]    When a part too large for the drop leaf table  21  is cut out by plasma torch, the CNC moves the W-axis of the loader/unloader  101  to position the magnetic platen  105  over the worktable  4  such that the magnets  107  are over the large part to be removed, then stops. The CNC commands the PLC  106  to reduce the magnetic field of all magnets to “0”. When the PLC  106  signals the CNC that all the magnets  107  are at “0” magnetic field strength, the CNC commands the smart drive of the loader/unloader  101  to move the Z-axis down until the sensor apparatus  116  indicates to the CNC that the workpiece  3 ′ has been contacted. The CNC instructs the PLC  106  which of the magnets  107  to energize and what magnetic field strength to employ. The PLC  106  energizes the specified magnets then sends an “ok to go” signal to the CNC. Upon receipt of the “ok to go” signal, the CNC commands the smart drive of loader/unloader  101  to move the Z-axis up. At a pre-designated time, when the magnetic platen  105  has been raised above the workpiece  3 ′ and if the magnetic fields are not already at full strength, the CNC commands the PLC  106  to energize the previously selected magnets to full magnetic field strength. Tentatively, the time is set to two seconds after the start of the up move. If the Z-axis reaches full up position before the magnets have been energized to full field strength, the CNC commands the PLC  106  to energize the previously selected magnets to full magnetic field strength at full up position. With the magnetic platen  105  at full up position, the sensor apparatus  116  communicating that the part is held by the platen, and the PLC  106  communicating that the selected magnets are at full field strength, the CNC moves the loader W-axis to a commanded position over the unloading zone  115  then stops. When the part has been moved horizontally clear of the worktable  4 , the CNC restarts processing the part program controlling machine tool  100 . The CNC will either drop the part into a container or stack the part on a table or a pallet.  
         [0092]    If the command is to drop the part, the CNC commands the PLC  106  to reduce the magnetic field strength of the selected magnets  107  to “0”. When the CNC receives a signal from the PLC  106  that the magnetic field strength is at “0” and receives confirmation from the sensor apparatus  116  that the magnets  107  no longer hold the part, the CNC commands the PLC  106  to energize all the magnets  107  to full strength, to conserve power, and moves the loader W-axis back to the standby position over the worktable  4 .  
         [0093]    If the command is to stack the part, the CNC commands the smart drive of the loader/unloader  101  Z-axis to lower the magnetic platen  105 . Z-axis motion stops when the sensor apparatus  116  indicates the workpiece  3 ′ has reached the surface of the pallet, table, or stack. Upon receipt of the contact signal, the CNC commands platen the PLC  106  to reduce the magnetic field strength of the selected magnets to “0”. When the CNC receives a signal from the PLC  106  that the magnetic field strength of all the magnets  107  is at “0”, the CNC commands the smart drive of the loader/unloader  101  Z-axis to move to the full up position. The smart drive of loader/unloader  101  Z-axis signals the CNC that the Z-axis is at the full up position then the CNC commands the PLC  106  to energize all the magnets  107  to full magnetic field strength to conserve power and moves the loader/unloader  101  W-axis back to the standby position over the worktable  4 .  
         [0094]    It can now be seen by one of ordinary skill in the art that the present invention provides a new and improved means to remove skeletal remnants from a plasma torch or laser equipped CNC punch press. The apparatus requires no extra space at the machine tool for storage of the removed skeletal remnants. No dedicated transfer device for the skeletal remnants is utilized, reducing manufacturing cost. In a preferred form, the scrap table  24  is adapted with conveyor rollers and functions to support the workpiece  3 ′ during operation of the machine tool  1  and to unload and stack a skeletal remnant. In alternate form the scrap table  124  can be adapted with ball transfer bearings such that it can reside proximate an automatic sheet loader and can support a workpiece during a load cycle, support the workpiece during operation of the machine tool  100  and unload and stack a skeletal remnant. In other alternate forms, the scrap tables  24 ,  124  can be adapted with skate wheel conveyors, barrel rollers, omni-wheels or brushes as best suits the application of the CNC punch press. Further, the scrap table  24  can be adapted with a pallet for stacking skeletal remnants on or a conveyor means for transporting skeletal remnants elsewhere for disposal or storage.  
         [0095]    All of the references cited herein, including patents, patent applications, and publications, are hereby incorporated in their entireties by reference.  
         [0096]    The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.