Abstract:
A tooling fixture is disclosed that includes a weldment having spaced apart lateral members interconnected by opposing side members. Spaced apart trunnions support the side members for rotation about an axis, in one example. A locating pin is arranged between each side member and trunnions to enable quick and accurate location of the tooling fixture relative to the trunnions. The pins are at a right angle relative to the axis, in one example. Tooling plates are removable secured to each of the lateral members. Adjustable brackets are secured to the tooling plates and support tooling that cooperates with a workpiece supported on the tooling fixture. In one example, jack blocks, shims, squaring plates and stops are used to permit precise adjustment and repeatable relocation of the tooling in three directions.

Description:
BACKGROUND 
     This disclosure relates to a tooling fixture used, for example, in an automated welding operation. 
     Tooling fixtures are frequently used in automated assembly processes, such as welding, riveting and clinching, to hold a workpiece during the operation. In one example, one or more tooling fixtures are indexed between various stations, for example, by using a vertical rotary table that operates in a ferris-wheel fashion, a linear sliding assembly, or a rotary table that operates in a horizontal plane. Often a worker will load and unload the workpiece to and from a tooling fixture at one station, and a robot will perform various operations on the workpiece mounted on the tooling fixture at another station. Trunnions are sometimes used to rotate the tooling fixture to a desired position for the worker and/or robot. 
     Typically, various locators, clamps and sensors are used to hold the part and detect the presence of the part to ensure proper positioning prior to performing operations on the workpiece. Tooling fixtures used for welding operations may also include components that transmit welding current, such as the workpiece lead, or provide cooling water and/or electrical or pneumatic connections. 
     Typical prior art welding fixtures present several problems. First, typical welding fixtures are highly customized such that they require significant reworking when being updated for a new workpiece, or the welding fixture must be scrapped. Second, it is difficult to accurately locate the various tooling such as locators, clamps and sensors within the welding fixture. This increases down time when the welding fixture is reconfigured for a new workpiece. Third, it is difficult to locate the welding fixture relative to any support structure, such as trunnions. The welding fixture must be accurately located relative the trunnions to prevent binding as the welding fixture is rotated into the desired position. Fourth, large portions of the electric and pneumatic lines are left exposed, which subjects them to damage when performing operations on the workpiece, for example, from welding sparks. 
     What are needed are more modular welding fixtures enabling quick and accurate positioning of both the tooling relative to the welding fixture and the welding fixture relative to the trunnions. It is also desirable to provide a welding fixture that provides better protection for electrical and pneumatic lines, for example. 
     SUMMARY 
     A tooling fixture is disclosed that includes a weldment having spaced apart lateral members interconnected by opposing side members. Spaced apart trunnions support the side members for rotation about an axis, in one example. A locating pin is arranged between each side member and trunnions to enable quick and accurate location of the tooling fixture relative to the trunnions. The pins are at a right angle relative to the axis, in one example. 
     Tooling plates are removable secured to each of the lateral members. Adjustable brackets are secured to the tooling plates and support tooling that cooperates with a workpiece supported on the tooling fixture. In one example, jack blocks, shims, squaring plates and stops are used to permit precise adjustment and repeatable relocation of the tooling in three directions. 
     The various locating features enable the tooling fixture to be removed from the work area and taken to a remote location for rework. The tooling can be quickly repositioned and verified at the remote location, for example, by using a coordinate measurement machine. The reworked tooling fixture can then be accurately mounted on the trunnions. 
     These and other features of the disclosure can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example welding operation work area using an example welding fixture in a rotary table configuration. 
         FIG. 2  is a partially exploded perspective view of the welding fixture supported by trunnions. 
         FIG. 3  is a perspective view of example tooling mounted on opposing tooling plates, which are to be secured to the welding fixture. 
         FIG. 4  is a top elevational view of the tooling shown in  FIG. 3  with the tooling plates secured to the welding fixture. 
         FIG. 5  is an exploded perspective view of an example bracket assembly used to secure the tooling to the tooling plate. 
         FIG. 6  is a partially exploded perspective bottom view of the welding fixture shown in  FIG. 4  without the brackets or tooling. 
         FIG. 6A  is an enlarged partially broken view of a connection panel. 
     
    
    
     DETAILED DESCRIPTION 
     An example welding operation work area  10  is shown schematically in  FIG. 1 . A workpiece  14 , such as a vehicle bumper, is retained by a welding assembly  12 . A robot  16  performs various operations upon the workpiece  14 , such as spot welding. 
     The example welding assembly  12  includes a base  20  supporting a turntable  22 . A framework  24  supported on the turntable  22  and includes modular tooling fixture weldments, or tooling fixtures  26 , mounted on opposing sides of the framework  24 . During operation, a worker loads and/or unloads the workpiece  14  at one station on one of the tooling fixtures  26 , and the robot  16  welds the workpiece  14  with its tool  18  on the other tooling fixture  26  at another station. Although the example illustrates a rotary table having a pair of tooling fixtures, it should be understood that the modular tooling fixture  26  can be used in other welding assembly configurations. Furthermore, the example tooling fixture  26  can be used in operation other than welding. 
     In the example arrangement, a pair of arms  28  is secured to the framework  24  to support each of the tooling fixtures  26 . The arms  28  include trunnions  30  that rotate the tooling fixtures  26  about an axis A to move the workpiece  14  in a desired position relative to the robot  16  and/or worker. At least one of the trunnions  30  for each tooling fixture  26  includes a headstock  32  having a motor  34  that rotationally drives the tooling fixture  26  about the axis A. The other trunnion  30  rotationally supports the other side of the tooling fixture  26 . 
     Referring to  FIGS. 1 and 2 , the example modular tooling fixture  26  is a box-shaped structure that includes side members  36  welded to spaced apart lateral members  38 . In one example, the trunnions  30  include supports  40  having a pad  42 . The side members  36  are supported by the pad  42  and secured relative thereto. The side members  36  must be located precisely relative to the pads  42  so that the tooling fixture  26  does not bind as the motor  34  rotates the fixture assembly  26  about the axis A. To this end, the side members  36  include locating plates  44 , which includes various locating features that will be discussed in more detail below. 
     Referring to  FIGS. 2-4  and  6 , the lateral members  38  include tooling plate mounts  46  to which tooling plates  48  are secured. Brackets  58 , which support tooling  50 , are secured to the tooling plates  48  in desired positions. It is desirable to quickly and precisely locate the tooling  50  for a particular workpiece  14  to reduce maintenance time and cost as well as the cost associated with part changeovers. 
     Referring to  FIG. 3 , typical tooling  50  employed for retaining the workpiece  14  includes locators  56  and clamps  54 , which hold the workpiece  14  in a desired position to ensure that the tool  18  engages the workpiece  14  at the desired locations. Shaping cylinders  52  are also employed in one example to exert forces on the workpiece  14  during welding operations to prevent distortion of the workpiece  14  from heat during welding. 
     Referring to  FIGS. 4 and 5 , the example brackets  58  are multi-piece components that are adjustable relative to one another to enable quick and easy position adjustments of the tooling  50 . In one example, a first plate  60  is secured to and arranged generally horizontally relative to the tooling plate  48 . A second plate  62  extends from the first plate  60  at a right angle, for example. The tooling plate  48  includes multiple holes  70  for receiving fastener  64 , which are threaded bolts, for example, that extend through enlarged holes  68  in the first plate  60 . Washers  66  are arranged between the fastener  64  and the first plate  60 . In one example, the washers  66  are relatively thick to distribute the clamping load exerted by the fastener  64  on the first plate  60 . The enlarged holes  68  have a diameter that is substantially larger than the diameter of the fastener  64  to enable adjustment of the bracket  58  in a plane X-Y corresponding to the tooling plate  48 . 
     A jack block  72  is secured to the tooling plate  48  by fasteners  74  received by holes  75 . The fasteners  74  extend through enlarged holes  73  to permit adjustment of the jack block  72 . Fastener  76  extends through holes  77  in the jack block  72  to secure the first plate  60  to the jack block  72 . A shim  71  having notches  78 , which accommodate the fastener  76 , is arranged between the jack block  72  and the first plate  60 . In the example shown, shims  71  and jack blocks  72  are arranged on either side of the bracket  58 . The jack block  72  can be used to ensure that the first plate  60  can easily be secured in its previous location if removed for servicing, such as a tooling change. 
     In one example method of adjustment, the fasteners  64 ,  74  are loosened and the shims  71  are removed. The large clearance between the fasteners  64 ,  74  and the enlarged holes  68 ,  73  enables the bracket to be adjusted in both the first and second directions in the X-Y plane. Once the bracket  58  is in a desired position, the fasteners  64  are tightened to secure the bracket  58  to the tooling plate  48 . New shims  71 , if necessary, are machined to a desired thickness for placement between the jack blocks  72  and the first plate  60 . The fasteners  76  are tightened to secure the jack blocks  72  and first plate  60  to one another. The bracket  58  can then be removed by leaving the jack blocks  72  secured and by removing the fasteners  64 ,  76  and shims  71 . The jack blocks  72  and replacement of the fasteners  76  locate the bracket  58  in the same Y position, and replacing the shims  71  locates the bracket  58  in the same X position. In this manner, the bracket  58  can be removed and replaced quickly and accurately. 
     A tooling pad  86  supports the tooling  50  relative to the bracket  58  using fasteners  92  that extend through washers  66  and enlarged holes  88  to threaded holes  89 . Squaring plates  80  are used on either side of the tooling pad  86  to locate and square the tooling pad  86  relative to the second plate  62  and prevent adjustment of the tooling pad  86  in the Y direction. In the example, fasteners  82  extend through washers  84  and enlarged holes  81  and are received in holes  83  to secure the squaring plates  80  to the tooling pad  86 . One side of the squaring plate  80  is secured to the second plate  62  using fasteners (not shown) and does not provide adjustability of the squaring plate  80  relative to the second plate  62  in the example. The squaring plate  80  permits the tooling pad  86  to be slid and adjusted in the Z direction. 
     A jack block  72  and shim  71  may also be used adjacent to the tooling pad  86  to set the desired Z position. A stop  90  limits the adjustment of the tooling pad  86  in the Z direction and can be used to quickly relocate the tooling pad  86  relative to the bracket  58  subsequent to removal to obtain the desired Z position provided by the shim  71 , similar to the method described above. The fasteners  82 ,  92  are loosened to permit adjustment of the tooling pad in the Z direction. 
     The tooling  50  can be positioned at a remote location by placing the tooling fixture  26  on a coordinate measurement machine. The brackets  58  and their tooling  50  can be adjusted and verified before the tooling fixture is mounted onto the framework  24 . 
     Referring to  FIGS. 2 and 6 , the modular tooling fixture  26  includes locating features that facilitate precise alignment of the tooling fixture  26  relative to the pads  42  associated with the trunnions  30 . This ensures that the tooling fixture  26  can be quickly and precisely positioned relative to the trunnions  30  to prevent binding of the tooling fixture  26  as it rotates about the axis A. As a result, the tooling fixture  26  can be removed from the work area for more rapid or cost effective retooling or maintenance at a remote location. 
     A plate  94  is secured to each of the side members  36 , such as by welding. An insulating sheet  96  is arranged between the plate  94  and the locating plate  44  to prevent welding current from passing through the tooling fixture  26  and into the rest of the welding assembly  12 . Nuts  98  are captured in a backside of the locating plate  44 . The nuts  98  includes bosses  100  that extend through and are located relative to holes  101  in the locating plate  44 . Fasteners  99  extend through holes in the pads  42  and are received by the nuts  98  to secure the tooling fixture  26  to the pads  42 . 
     Insulating tubes  102  extend through holes in the locating plate  44 , insulating sheet  96  and plate  98  to precisely locate the locating plate  44  relative to the plate  94 . Fasteners  105  extend through the insulating tubes  102  secure the locating plate  44  relative to the plate  94 . Insulating washers  104  are arranged between the fasteners  105  and the locating plate  44 . 
     Bushings  106  are received by holes  107  in the locating plate  44  and support locating pins  110  ( FIG. 2 ) extending from each pad  42 . In one example, the bushings  106  are only received in the locating plate  44  and are isolated from the plate  94  by the insulating sheet  96 . This is desirable, for example, since the bushings  106  are subject to impact forces and wear when the tooling fixtures  26  are located and secured relative to the pads  42 . A locating pin  108  may also be provided on the plate  94  and received in a corresponding hole  109  in the pads  42 . 
     In the example tooling fixture  26 , the pins  108 ,  110  and their corresponding holes  109 ,  106  are arranged transverse to the axis A. The pins  108 ,  110  are arranged perpendicularly, for example, relative to a plane P provided by the tooling fixture  26 . In this manner, the tooling fixture  26  can be raised vertically off and lowered vertically on the pads  42  during dismounting and mounting. 
     Referring to  FIG. 6 , the tooling fixtures  26  includes enclosures  112  adjacent to the tooling plate  48  for protecting various tooling wires and lines from damage, for example, during workpiece loading and unloading and from welding sparks. Enclosure  112  includes walls  114  that provide a cavity  125  for housing the wires and lines. Access panels  116  are movable relative to the lateral members  38  about hinges  118  to an open position, providing access to the wires and lines within the cavity  125 . The access panels  116  are retained in a closed position by latches  120 . The side members  36  include access holes  122  that enable the wires and lines to be more easily routed through a passage  123  in the side members  36  between the lateral members  38  from an area exterior to the tooling fixture  26 . 
     Referring to  FIGS. 6 and 6A , the enclosure  112  includes a connection panel  128  that provides access between the tooling  50  and the cavity  125  provided by the enclosure  112 . The connection panel  124  includes knock-outs  126  that when removed provide holes  128 . A connector  130  can be mounted within each hole  128 , for example, or the wires/lines  132  can be passed through the holes  128  from the cavity  125  to an area exterior to the tooling fixture  26 . The connector  130  is a quick connect pneumatic fitting, in one example. 
     In one example, the tooling fixtures  26  include a valve enclosure  134 , shown in  FIG. 6 . The valve enclosure  134  at least partially encloses and protects valves  136  that are used to selectively actuate the cylinders  52  and clamps  54 , for example. 
     Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of the claims. For that reason, the following claims should be studied to determine their true scope and content.