Patent Document

REFERENCE TO RELATED APPLICATION 
   The application claims priority to U.S. Provisional Application No. 60/617,969 that was filed on Oct. 12, 2004. 

   BACKGROUND OF THE INVENTION 
   This invention generally relates to a tool mounting system for a workpiece transfer system. More particularly, this invention relates to a tool mounting system mountable to a workpiece transfer system. 
   A workpiece transfer system includes a bar that moves a workpiece between desired locations. Often the workpiece transfer system will move body panels between stamping stations. Tools such as grippers or vacuum cups are attached to the bar and grasp a workpiece at one location and release the workpiece at another location. The tools often utilize pressurized air for actuation and therefore need numerous pneumatic couplings and conduits that are attached to the bar. 
   In many applications of workpiece transfer systems, the clearance between the bar and the stamping station is limited. Accordingly, each part must fit within certain defined space restrictions. This includes the pneumatic and electrical wires that supply and control actuation of the gripper and vacuum tools. 
   Further, it is often the case with many transfer systems that multiple workpiece configurations are fabricated within the same line. The stamping dies are changed over along with the tooling required to move the workpieces between stations. Rigidly attached tooling makes change over difficult and time consuming. 
   Accordingly, it is desirable to design a transfer system that provides for switching of tooling while remaining within the space limitations of the transfer system. 
   SUMMARY OF THE INVENTION 
   An example tool mount assembly according to this invention includes drop down connections to aid in mounting of a tool to an adaptor plate and a fail-safe tool mounting system for preventing installation of a tool in an undesired or incorrect manner. 
   The example tool mount assembly includes an adaptor that is mounted to a bar of a part transfer machine. A plurality of tool mount arms are received within the adaptor and are specifically tailored to provide proper placement of tools such as grippers or vacuum cups relative to a specific panel or part configuration. The adaptor includes several mounting locations to receive a plurality of arms. 
   Each mounting location of each arm includes a fail-safe mounting allowing only the specified tooling to be installed. In this manner, it is not possible to properly install a tool in an incorrect location. The fail-safe mounting is provided by a specified desired distance between a base quick lock connection and a second connection. Each of the second connections includes a lug that is dropped down into a lug mount. The drop down feature provided by the lug and lug mount ease mounting of the tool to speed tool change over. 
   These and other features of the present invention 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 bar tool mounting system according to this invention. 
       FIG. 2  is another perspective view of the example bar tool mounting system with a rail removed. 
       FIG. 3  is a schematic view of an example lug mount according to this invention. 
       FIG. 4  is a top schematic view of example drop down lug mounts according to this invention. 
       FIG. 5  is a cross-sectional view of the example tool mounting system. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , the workpiece transfer system  10  includes a bar  12  that moves a workpiece  20  between workstations (not shown). An adaptor  14  is attached to the bar  12  and supports the tools  18 . The tools  18  extend from removable rails  16  attached to the adaptor  14 . The tools  18  illustrated are pneumatically actuated suction cups. However, other tools as are known would also benefit from the disclosures of this invention, for example mechanical grippers and part present sensing devices. 
   The rail  16  is part of a rail assembly. There are four rail assemblies  42 ,  44 ,  46  and  48  illustrated. The tools  18  are mounted to arms  22  that are in turn mounted to the rail  16  of each rail assembly  42 ,  44 ,  46  and  48 . The position of the tools  18  along the rail  16  is infinitely adjustable such that the configuration and placement of the tools  18  can be tailored to the requirements of a specific application and workpiece  20 . 
   Each of the rail assemblies  42 ,  44 ,  46  and  48  include a mount plug  25  that is attachable to selectively releasable mount connector  24  attached to the adaptor  14 . The mount plug  25  is affixed to a first end of the rail  16  for each of the rail assemblies  42 ,  44 ,  46  and  48 . The mount plug  25  interfaces with the mount connector  24  to communicate pressurized air and provide an electrical connection for any electrical devices mounted to the rail  16 . The mount connector  24  includes a locking device  27  movable between a released position where the rail  16  may be removed and a secured position where the rail  16  is rigidly held into the mount connector  24 , and the desired electrical and pneumatic connections are completed. 
   The example rail assembly  42  includes a sensor  38  for detecting the presence of the workpiece  20 . The sensor  38  is electrically attached through the interface between the mount plug  25  and the mount connector  24 . The mount connector  24  is in turn in communication with a source of electrical energy and pressurized air. Further, the mount connector  24  is adaptable for providing communication of control signals to the tools  18  mounted to the rail  16 . 
   The mount connector  24  also provides support of an end of the rail  16 . The second end  28  of the rail  16  is supported by a lug  32  that fits within a lug mount  30 . The lug  32  on the rail  16  is first placed within the lug mount  30  and slid axially into full engagement with the mount connector  24 . The lug mount  30  receives the lug  32  within a slot  35  that includes a vertical portion  37  and horizontal portion  39 . The lug  32  drops within the vertical portion  37  of the slot  35  and is slid axially within the horizontal portion  39  of the slot to facilitate axial engagement and securement of the mount plug  25  within the mount connector  24 . Although a mount connector  24  and mount plug  25  are illustrated, it is within the contemplation of this invention to utilize other mounting devices that are known in the art. 
   The rail assemblies  42 ,  44 ,  46  and  48  are installed to the adaptor  14  in a specific location. Each of the rail assemblies  42 ,  44 ,  46  and  48  are adapted to fit only one location to assure a desired orientation of the rail assemblies  42 ,  44 ,  46  and  48  to comply with application specific requirements. Each of the rail assemblies  42 ,  44 ,  46  and  48  are identified by a color code. The color of the lug  32  corresponds to a color on the lug mount  30  to provide a determination of the correct position for mounting of the rail assembly. 
   The color code in the illustrated example is green for the rail assembly  42  and is indicated schematically by shading  17 B on the the rail assembly  42  and shading  17 A on the lug mount  30 . The rail assembly  46  includes a gold color code schematically indicated at  19 A on the rail  16  and a matching gold color indicated at  19 B on the lug mount  30 . The rail assembly  44  includes a silver color code (not shown) and the rail assembly  46  includes a black color code (not shown). The color-codes  17 A and  19 A disposed on the rail  16  of each rail assembly  42 ,  46  comprise a colored tape. The color-codes  17 B and  19 B on the lug mounts  30  are provided by a desired plating color. As appreciated, other colors and method of adhering that color to the lug mount and the rail may be utilized to identify each position on the adaptor  14  with the corresponding one of the rail assemblies  42 ,  44 ,  46  and  48 . The different color codes provide for easy identification of the proper location for the rail assembly. 
   Referring to  FIG. 2 , the rail assembly  42  is illustrated removed from the rail adaptor  14 . The rail assembly  42 , like the other rail assemblies  44 ,  46  and  48  includes a length  50  between the lug  32  and a portion of the mount plug  25 . The length  50  for each of the rail assemblies is unique such that one rail assembly cannot be assembled into the place of another rail assembly. In the example illustrated in  FIG. 2 , the rail assembly  46  includes a length  54  that is different than the length  50  such that the rail assembly  46  cannot be assembled in place of the rail assembly  42 . The length  50  between the lug  32  and the end of the mount plug  25  corresponds to a length  52  between the mount connector  24  and the lug mount  30 . The length  52  is measured from a stop of the mount connector  24  and a position within the horizontal portion  39  of the slot  35  within the lug mount  30 . 
   The length  50  between the lug  32  and the end of the mount plug  25  is a dimension that is fabricated within desired tolerances to provide the desired fit once mounted. As appreciated, some prior art tool mounting devices include multiple critical dimensions that must be closely controlled to provide the desired fit, or event to allow assembly. The instant tool mounting system includes only a single closely held dimension, thereby simplifying assembly, and fabrication. 
   The rail assembly  42  is easily removable by unlocking the mount plug  25  from the mount connector  24  and moving the entire rail axially away from the mount plug  25  until the lug  32  is free to move vertically within the slot  35  of the lug mount  30 . Another rail assembly including tooling for a differently shaped and configured workpiece can then be installed to provide a relatively quick and easy tooling change over. 
   In operation, several sets of rail assemblies will be provided that correspond to various and differently configured workpieces. Change over is conducted by removing one set of color-coded rail assemblies and installing another set in the proper color coded locations. Rail assemblies can only be properly installed into corresponding locations due to the different lengths  50  and  54  between the mount connector  24  and the lug mount  30 . 
   Referring to  FIG. 3 , the lug mount  30  is shown without the rail and adaptor for clarity. The lug mount  30  includes the slot  35  having the vertical portion  37  and the horizontal portion  39 . The drop down feature provided by the lug  32  being received in the slot  35  facilitates quick assembly of a rail assembly. The lug  32  includes a bushing  33  that supports the tool and prevents twisting during installation. The drop down feature thereby prevents twisting of the rail assembly during assembly, thereby substantially eliminating the need for an assembler to support the rail assembly during the entire assembly process. 
   Referring to  FIG. 4 , the lug mount  30  is shown schematically that correspond to mounting arrangements for the rail assembly  42  and the rail assembly  46 . The slot  35  includes a width  58  for the lug  32 . The lug  32  includes the bushing  33  supported on a shaft  31 . The shaft  31  includes a diameter  60  that corresponds with the width  58  that provides for assembly of the lug  32  within the slot  35 . The width  58  is tailored to each of the rail assemblies  42 ,  44 ,  46  and  48  such that each of the rail assemblies  42 ,  44 ,  46  and  48  includes a tailored width  58  unique to that particular rail assembly. 
   Accordingly, the rail assembly  46  is partially shown with the lug  32  having a shaft  31  of a diameter  64  different than the diameter  60  for the rail assembly  42 . The lug mount  30  for the rail assembly  46  includes a width  62  of the slot  35 ′ that prevents another rail assembly, such as for example the rail assembly  42  from being installed within the lug mount  30  instead of the rail assembly  46 . Accordingly, the different diameters for each shaft  31  of each of the rail assemblies  42 ,  44 ,  46  and  48  substantially prevent assembly of a rail assembly in a non-desired orientation. 
   Referring to  FIG. 5 , a cross-section of the transfer system  10  is shown with the adaptor  14  attached to the bar  12 . As appreciated, the transfer system  10  operates within a space-restricted environment. In some applications, it is desired to limit or eliminate mounting of devices or objects to the top of the bar  12 . Such applications may not allow the mounting of electrical wire harnesses and airlines to the top surface of the bar  12 . In such applications, the instant adaptor  14  provides the necessary mounting and communication of air and electric to the tooling without extending substantially beyond the top surface of the bar  12 . The addition of the adaptor  14  adds only the minimal thickness of the adaptor  14  to the overall height of the bar  12 . 
   Accordingly, the inventive workpiece transfer system  10  includes several features that assure proper configuration of the several rail assemblies  42 ,  44 ,  46  and  48  that expedite and facilitate quick tool changeover. Different lengths between mounting points for each rail assembly and tailored diameters of shafts for each lug accompanied by color-coded parts provides for fail safe and efficient tool change over. Further, the drop down mounting provided by the lug and lug mount tool mount configuration eases mounting by eliminating awkward and difficult maneuvering of the rail assemblies during the mounting process. 
   Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.

Technology Category: 4