Abstract:
An exemplary reconfigurable workpiece support fixture according to an embodiment of the present invention includes a base, and a plurality of spaced-apart plates are removably attachable to the base. Each plate defines a plurality of notches along an angular profile. A plurality of spaced-apart manifolds are receivable in the plurality of notches, and each manifold spans across the plurality of plates. A plurality of attachment devices are removably attachable to the plurality of manifolds.

Description:
[0001]    This application is a divisional of application Ser. No. 11/134,775, filed May 20, 2005, status allowed. 
     
    
     BACKGROUND 
       [0002]    During machining, polishing, grinding, or other fabrication processes performed on a workpiece, the workpiece is typically held securely in place on a support fixture. This secure placement on the support fixture is typically accomplished by holding devices, such as suction cups, that securely hold one side of the workpiece onto the workpiece support fixture. This arrangement permits end effectors, cutters, or other machining devices to act upon another side of the workpiece without interference by the holding devices. 
         [0003]    It is common for design of a part to be revised during the life cycle of the part, thereby entailing changes in the fabrication and processing of the part. It is generally more cost-effective to reconfigure the workpiece support fixture to accommodate several revised designs of a part than it is to procure a separate workpiece support fixture for each different revised part. It is also desirable to use a workpiece support fixture for fabrication of more than one part thereon, thereby increasing the return on investment in the workpiece support fixture. As a result, changes may be made to configuration of the workpiece support fixture to accommodate revisions to designs of parts fabricated thereon or to accommodate fabrication of different parts thereon. 
         [0004]    Therefore, it would be desirable to design workpiece support fixtures that are reconfigurable. One currently known reconfigurable workpiece support fixture provides a base with a number of stations. Each station includes a clamp block, and a frame element of predetermined profile may be clamped in the clamp block in either of two orientations. Each frame element includes a number of suction cups with plumbing internal to the frame element. Suction to the suction cups of each separate frame element is controlled by a separate valve for each frame element. The several valves are provided on the base, and each separate valve is connected to the internal plumbing of its associated frame element. The workpiece support may be configured for a symmetric component by unclamping and rotating the frame elements through 180 degrees. The workpiece support may also be reconfigured for different profiles by selecting a set of appropriate frame elements from a library of frame elements. 
         [0005]    Reconfiguring such a known workpiece support thus entails use of clamping blocks, complex frame elements with internal plumbing, a separate valve connected to the internal plumbing of each complex frame element, and a library of such complex frame elements. Fabricating such a complex workpiece support and a library of complex frame elements for different profiles is expensive. Moreover, reconfiguring such a known workpiece by unclamping and rotating frame elements, or retrieving a set of appropriate frame elements from a library of frame elements, and connecting internal plumbing of each frame element to its associated valve is time and labor intensive. Further, storage of a library of frame elements uses facility space for storage of unused fixture components, thereby preventing that facility space from being used for productive use. 
         [0006]    Moreover, advances in manufacturing technology such as determinant assembly still entail stabilizing a workpiece on a workpiece support fixture. Determinant assembly is a method of self-indexing of detail parts to each other to create an assembly. By using determinant assembly, parts can be assembled with a minimum number of tools. However, the tooling and machinery that are used to accomplish determinant assembly have been complex and capital intensive. 
         [0007]    The foregoing examples of related art and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
       SUMMARY 
       [0008]    The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the problems described above in the Background have been reduced or eliminated, while other embodiments are directed to other improvements. 
         [0009]    Embodiments of reconfigurable workpiece support fixtures are reconfigurable to support a variety of workpieces of different sizes and configurations during manufacturing, fabrication, assembly operations, or the like. Through use of modular concepts, reconfigurable workpiece support fixtures according to embodiments of the present invention advantageously may be built more simply, may be more flexible, and may be modified for different configurations more quickly than known fixtures. Moreover, embodiments of the present invention may be used to support determinant assembly operations, if desired. 
         [0010]    An exemplary reconfigurable workpiece support fixture according to an embodiment of the present invention includes a base, and a plurality of spaced-apart plates are removably attachable to the base. Each plate defines a plurality of notches along an angular profile. A plurality of spaced-apart manifolds are receivable in the plurality of notches, and each manifold spans across the plurality of plates. A plurality of attachment devices are removably attachable to the plurality of manifolds. 
         [0011]    According to an exemplary aspect, one dimension, such as length, of the workpiece support fixture may be reconfigured by changing the number of attachment devices that are removably attached to the plurality of manifolds. For example, each manifold may define a plurality of spaced-apart receptacles, and each receptacle is configured to receive any of the plurality of attachment devices therein. The receptacles that are within the edges of a workpiece may have the attachment devices removably received therein. The receptacles that are beyond the edges of the workpiece may each removably receive in sealing engagement therewith a receptacle cover. As a result, one dimension of the workpiece support fixture may be quickly and easily reconfigured by use of attachment devices within the edges of the workpiece and receptacle covers to seal the receptacles beyond the edges of the workpiece. Such a reconfiguration of this dimension of the workpiece support fixture is advantageous when the attachment devices include suction cups that are connected to a vacuum source. 
         [0012]    According to another exemplary aspect, another dimension, such as width, of the workpiece support fixture may be reconfigured by use of different headers that define different numbers of notches. Alternately, the dimension, such as width, of the workpiece support fixture may be reconfigured by changing the number of manifolds that are received in the notches. 
         [0013]    According to another exemplary aspect, angular profile along curved, upper surface of the headers contributes to controlling configuration of the workpiece support fixture. That is, different angular profiles can be defined along the curved, upper surface of different sets of headers. 
         [0014]    In other embodiments, the workpiece may be held in place with any suitable attraction force that is appropriate for the workpiece being worked upon. For example, the attraction force may be a magnetic force when the workpiece is made of a material that may be attracted to a magnetic force. In this embodiment, the attachment devices may include any suitable electromagnets. The electromagnets that extend beyond the end of the workpiece need not be removed. Instead, the electromagnets that extend beyond the end of the workpiece may simply remain in place. 
         [0015]    In addition to the exemplary embodiments and aspects described above, further embodiments and aspects will become apparent by reference to the drawings and by study of the following detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]    Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
           [0017]      FIG. 1  is a perspective view of an exemplary reconfigurable workpiece support fixture according to an embodiment of the invention; 
           [0018]      FIG. 2  is a perspective view of a workpiece supported by the reconfigurable workpiece support fixture of  FIG. 1 ; 
           [0019]      FIGS. 3 and 4  are perspective views of machining operations being performed on a workpiece supported by the reconfigurable workpiece support fixture of  FIG. 1 ; and 
           [0020]      FIG. 5  is a perspective view of an exemplary reconfigurable workpiece support fixture according to another embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0021]    Referring to  FIG. 1 , an exemplary embodiment of a reconfigurable workpiece support fixture  10 , given by way of non-limiting example, is reconfigurable to support a variety of workpieces (not shown) of different sizes and configurations during manufacturing, fabrication, assembly operations, or the like. Through use of modular concepts, the exemplary reconfigurable workpiece support fixture  10  advantageously may be built more simply, may be more flexible, and may be modified for different configurations more quickly than known fixtures. Moreover, the exemplary reconfigurable workpiece support fixture  10  may be used to support determinant assembly operations, if desired. 
         [0022]    By way of overview and still referring to  FIG. 1 , parallel headers  12  are attached to a base  14 . Each header  12  is a flat, substantially planar plate that defines notches  16  along an angular profile, such as an arc. A manifold  18  is received in each of the notches  16  such that the manifolds  18  are parallel to each other and perpendicular to the planes of the headers  12 . Each manifold  18  spans across the headers  12  and includes attachment devices  20 , such as removable suction cups. A workpiece (not shown) is placed on the suction cups  20  and vacuum is applied to each of the manifolds  18 . The workpiece and the manifolds  18  are drawn toward each other, and the manifolds  18  engage sides of the notches, thereby causing the manifolds  18  to be held in place. The configuration of the fixture  10  may be changed by use of different headers  12  that define different numbers of notches  16  and/or define different angular profiles, or by use of different numbers of suction cups  20  along the manifolds  18 , or by use of different numbers of manifolds  18  as desired. Details of construction and operation of the fixture  10  will be explained below. Other embodiments will also be explained. 
         [0023]    The base  14  includes blocks  22 , such as angle irons. The blocks  22  are spaced at intervals along sides of the base  14 . Each block  22  defines a substantially flat face. Each block  22  defines a female receptacle for receiving therein a fastener  24 , such as a pin. Similarly, each header  12  defines a hole that corresponds to location of the female receptacle defined in a corresponding block  22 . The header  12  is placed against the blocks  22  so the hole in the header  12  lines up with the female receptacles in the blocks  22 . The fastener  24  is placed in the female receptacles in the blocks  22  and through the hole in the header  12 , thereby pinning the header  12  to the base  14 . 
         [0024]    A vacuum distribution manifold  26  is attached to the base  14 . An inlet port  28  is provided for connecting the vacuum distribution manifold  26  to a vacuum source (not shown). Vacuum hoses  30  are connected at one end  32  to outlet ports (not shown) of the vacuum distribution manifold  26  and at another end  34  to the manifolds  18 . 
         [0025]    Each header  12  is a flat, substantially planar plate. The notches  16  are defined, such as by machining, along and normal to a curved, upper surface of each header  12 . The curved, upper surface of the header  12  defines an angular profile, such as an arc as shown in  FIG. 1 , that corresponds to a profile of a particular workpiece that is to be machined on the fixture  10 . It is the profile of the headers  12  that corresponds to the profile of the workpiece. That is, the headers  12  control configuration of the fixture  10  to correspond to the profile of the workpiece. In corresponding to the profile of the workpiece, the upper surface of the header  12  may have any shape as desired for a particular application. For example, a workpiece may have a built-up section, such as an edge that is thicker than other parts of the workpiece. In such a case, then a notch or other similar depression, such as clearance depression  13 , may be cut out of the part of the upper surface of the header  12  to provide relief to the corresponding built-up area of the workpiece. 
         [0026]    Width capacity of the fixture  10  to accommodate workpieces of different configurations is simply and easily changed by use of different headers  12  that define different numbers of notches  16 . In addition, the angular profile along the curved, upper surface of the headers  12  contributes to controlling configuration of the fixture  10 . That is, different angular profiles can be defined along the curved, upper surface of different sets of headers  12 . Each set of headers  12  with the same angular profile corresponds to a profile of a desired workpiece. By changing sets of headers  12  from one set of headers  12  with one angular profile to another set of headers  12  with another angular profile, configuration of the fixture  10  can be changed to accommodate different workpieces with different angular profiles. 
         [0027]    Alternately, if desired, width capacity of the fixture  10  to accommodate workpieces of configurations with different widths but with a same angular profile is simply and easily changed by merely using the number of the manifolds  18  as desired to fit within edges of a workpiece to be supported. The manifolds  18  may simply be placed in the corresponding notches  16  as desired for a particular workpiece. If the angular profile of the upper surface of the header  12  is substantially uniform, then the manifolds  18  may be placed in the notches  16  anywhere along the angular profile as desired. That is, in such a case, the manifolds  18  need not uniformly populate the notches  16  from a central notch  16  outwardly toward the notches  16  toward ends of the headers  12 . For example, in  FIG. 2 , an unpopulated notch  17  does not support a manifold  18 . However, in some other cases it may be desirable to uniformly populate the notches  16  from a central notch  16  outwardly toward the notches  16  toward ends of the headers  12 . Regardless, the manifolds  18  may simply be placed in the corresponding notches  16  as desired for a particular workpiece. 
         [0028]    The manifolds  18  communicate vacuum to the suction cups  20 . Each manifold  18  is a substantially rectangular box that spans across all of the headers  12 . Each manifold  18  is slid or placed freely in its corresponding notches  16  along the curved, upper surface of the headers  12 . One end of each manifold  18  defines an inlet port (not shown) that is connected to the end  34  of one of the vacuum hoses  30 . Another end of each manifold  18  is sealed shut (that is, vacuum-tight). As a result, the manifold  18  is placed in the notches  16  with the “inlet port” end of the manifold  18  placed toward the vacuum distribution manifold  26  for connection with the hoses  30 . 
         [0029]    A series of receptacles such as holes or pockets or the like (not shown in  FIG. 1 ) are defined along a top side of each manifold  18  between the ends of the manifold  18 . Each receptacle is lined with a seal, such as an O-ring (not shown). A suction cup  20  sits loosely on top of the receptacle in sealing engagement with the seal. Advantageously, the suction cups  20  may be any commercial, off-the-shelf (COTS) suction cup that is readily available, as desired. Given by way of nonlimiting example, a suitable suction cup is the “Flip-Pod”, Part No. 84408, available from Horst Witte Geratebau Barskamp of Bleckede, Germany. If the workpiece has a built-up area such as a thicker edge as described above, then the suction cups  20  on the manifolds  18  at the edge of the workpiece may be shorter than the rest of the suction cups  20 . The shortened suction cups  20  at the edge of the workpiece may be made simply by cutting down the same type of suction cup used for the remainder of the suction cups  20 . Alternately, an adjustable height suction cup may be used, such as the “Height Adjustable Flip-Pod”, Part No. 90860, available from Horst Witte Geratebau Barskamp of Bleckede, Germany. 
         [0030]    Length capacity of the fixture  10  is easily controlled by varying the number of the suction cups  20  that are placed on the manifolds  18 . That is, if holding a workpiece or part does not require suction along the full length of the manifolds  18 , then the suction cups  20  that extend beyond the end of the workpiece are removed and the receptacle is sealed with receptacle cover, such as a flat piece of material (such as plastic, sheet metal, or the like) that is placed in sealing engagement across the seal. As a result, configuration of the fixture  10  advantageously is controlled in part simply by use of COTS suction cups and receptacle covers such as flat pieces of plastic or metal. Advantageously and as a result, same-sized manifolds  18  can be used across several different configurations of the fixture  10  as desired for fabricating or machining any number of different workpieces, as desired. 
         [0031]    An advantageous feature of the fixture  10  is engagement of the manifolds  18  and the notches  16  for holding together the manifolds  18  and the headers  12 . As discussed above, the angular profile defined by the curved, upper surface of the header  12  corresponds to the profile of the particular workpiece that is to be machined on the fixture  10 . The manifolds  18  rest in the notches  16  that have been defined normal to the curved, upper surface of the headers  12 . The workpiece is placed on top of the suction cups  20 , and suction is applied to the suction cups  20  from the vacuum source via the vacuum distribution manifold  26 , the vacuum hoses  30 , and the manifolds  18 . Weight of the workpiece causes the workpiece to be gravitationally urged downwardly toward the manifolds  18 . In addition, suction causes the manifolds  18  to be urged upwardly toward the workpiece. 
         [0032]    Advantageously, as the manifolds  18  are urged upwardly toward the workpiece, the manifolds  18  engage sides of the notches  16  (except for the notch  16  at the center of the header  12  as described below) that are defined at an angle relative to the relative motion between the workpiece and the manifolds  18 , thereby holding the manifolds  18  to the headers  12 . As a result, a clamping force between the headers  12  and the manifolds  18  advantageously is created without use of any mechanical clamping or anchoring devices whatsoever. It will be noted that the notch  16  at the center of the header  12  is aligned with gravitational urging of the workpiece and a direction of attraction of the manifold  18  toward the workpiece due to suction. As a result, the manifold  18  travels upwardly in a direction aligned with sides of the notch  16  at the center of the header without engagement. 
         [0033]    Referring now to  FIG. 2 , a workpiece  40  is supported by the reconfigurable workpiece support fixture  10 . The reconfigurable workpiece support fixture  10  is seen from the opposite end as in  FIG. 1 . To that end,  FIG. 2  does not show the vacuum distribution manifold  26  and the vacuum hoses  30 . Given by way of non-limiting example, the workpiece  40  may be a fuselage skin for an aircraft. However, the workpiece  40  may be any workpiece as desired. For example, the workpiece  40  may be a wing skin for an aircraft; a vehicle panel such as a roof top, a trunk lid, a hood, a door, or the like; or any workpiece as desired for a particular application. 
         [0034]    In this non-limiting example, the workpiece  40  extends across all of the manifolds  18  but does not span all the receptacles (not shown) of the manifolds  18 . Therefore, receptacle covers  42  (described above) sealingly engage seals (not shown) and seal the receptacles that extend beyond the edge of the workpiece  40 . 
         [0035]    Referring now to  FIG. 3 , the workpiece  40  is supported by the reconfigurable workpiece support fixture  10 . An end  44  of the workpiece  40  is trimmed with a cutting device  46  having a blade  48 . The blade  48  trims the end  44  at a safe distance beyond the ends of the manifolds  18  (at the ends of the manifolds  18  that are not connected to the vacuum hoses  30 . 
         [0036]    Referring now to  FIG. 4 , the workpiece  40  is supported by the reconfigurable workpiece support device  10 . An edge  50  of the workpiece  40  is trimmed with the blade  48  of the cutting device  46 . The blade  48  trims the edge  50  at a safe distance beyond the ends of the headers  12 . Other types of “machining” operations suitably include drilling and edge profiling. Routing, grinding, and polishing can also be performed by using different types of “cutters” in the spindle of the machine. The workpiece support fixture  10  can be used to support work for either a conventional multi-axis machine or a manufacturing robot as desired for a specific application. The workpiece support fixture  10  can also support determinant assembly operatons. 
         [0037]    In other embodiments, the workpiece may be held in place with any suitable attraction force that is appropriate for the workpiece being worked upon. For example, the attraction force may be a magnetic force when the workpiece is made of a material that may be attracted to a magnetic force. Referring now to  FIG. 5 , an exemplary reconfigurable workpiece support fixture  200  according to another nonlimiting embodiment includes attachment devices  220 . The attachment devices  220  may include any suitable electromagnets. The electromagnets  220  are electrically connected to an electrical source (not shown) as desired to attach the workpiece to the reconfigurable workpiece support fixture  200 . In one non-limiting embodiment, an electrical junction box  226  is attached to the base  14 . An input jack  228  is provided for electrically connecting the electrical junction box  226  to the electrical source (not shown). Wires or cables  230  are electrically connected at one end  232  to output jacks (not shown) of the electrical junction box  226  and at another end  234  to manifolds  218 . The electromagnets  220  are electrically coupled to receive electrical power from the electrical connection between the end  234  of the wire or cable  230  and the manifold  218 . In this embodiment, the electromagnets  220  that extend beyond the end of the workpiece advantageously need not be removed. Instead, the electromagnets  220  that extend beyond the end of the workpiece may simply remain in place. All other details of construction and operation of the reconfigurable workpiece support fixture  200  are the same as those for the reconfigurable workpiece support fixture  10  ( FIG. 1 ) and need not be repeated. 
         [0038]    While a number of exemplary embodiments and aspects have been illustrated and discussed above, those of skill in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions, and sub-combinations as are within their true spirit and scope.