Abstract:
A robot cell comprises a support having a top surface within a plane and configured to rotate about a central axis substantially normal to the plane and a plurality of welding tables including a first welding table and a second welding table. The first welding table is operably connected to the support and configured to rotate about a first axis substantially parallel to the plane and about a second axis substantially normal to the plane. The first welding table is configured such that the second axis remains substantially normal to the plane while the first welding table rotates about the first axis. The second welding table is operably connected to the support and configured to rotate about a third axis substantially parallel to the plane and about a fourth axis substantially normal to the plane. The second welding table is configured such that the fourth axis remains substantially&#39; normal to the plane while the second welding table rotates about the third axis.

Description:
[0001]    This application is a continuation of U.S. patent application Ser. No. 11/401,039 filed on Apr. 10, 2006, which is hereby incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Robots have been used in welding operations for some time. An example of such is disclosed in U.S. Pat. No. 6,772,932, which is incorporated by reference. Typically, a robot arm having a welding torch at a distal end welds a work piece positioned on a work table, which can also be referred to as a welding table. The work table is located in a welding cell and the robot is programmed to weld along a desired path. 
         [0003]    In known welding cells, work tables have limited movement with respect to the robot arm. For the robot arm to weld along the desired path, it is the robot arm that moves with respect to the work table, as opposed to the work table being able to move with respect to the robot arm. Greater flexibility with regard to the welding path could be achieved if the work table was able to move. 
       SUMMARY OF THE INVENTION 
       [0004]    A robotic welding cell includes a frame, a robot arm connected to the frame, a welding gun affixed to the robot arm, a welding table connected to the welding frame, and means to move the welding table in or about at least two mutually perpendicular axes. The means to move can comprise a motor operatively connected to the welding table. 
         [0005]    A welding table assembly for use in a robotic welding cell is also disclosed. The welding table assembly includes a welding table, a first powered drive assembly operatively connected to the welding table, and a second powered drive assembly operatively connected to the welding table. The first drive assembly rotates the welding table about a first axis. The second drive assembly rotates the welding table about a second axis. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a welding cell unit. 
           [0007]      FIG. 2  is a top plan view of the welding cell unit of  FIG. 1 . 
           [0008]      FIG. 3  is a view taken along line  3 - 3  of  FIG. 2 . 
           [0009]      FIG. 4  is a top plan view similar to the view of  FIG. 2  where a platform that is disposed in the welding cell unit has rotated from the position shown in  FIG. 2 . 
           [0010]      FIG. 5  is a close-up perspective view of a welding table assembly for the unit disclosed in  FIG. 1 . 
           [0011]      FIG. 6  is a top plan view of the assembly depicted in  FIG. 5 . 
           [0012]      FIG. 7  is a first side elevation view of the assembly depicted in  FIG. 5 . 
           [0013]      FIG. 8  is a second side elevation view of the assembly depicted in  FIG. 5  taken 90° from the view show in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    With reference to  FIG. 1 , a welding cell unit  10  generally includes a frame  12 , a robot  14  disposed within the frame, and first and second welding tables  16  and  18 , respectively, also disposed of within the frame. The robot welding unit  10  is useful for welding work pieces  22  and  24  in a manner that will be described in more detail below. 
         [0015]    In the depicted embodiment, the frame  12  includes a plurality of side walls and doors to enclose the robot  14  and the welding tables  16  and  18 . Even though a substantially rectangular configuration in plan view is shown, the frame  12 , and the unit  10 , can take numerous configurations. 
         [0016]    A front access door  26  mounts to the frame  12  to provide access to the interior of the frame. As more clearly seen in  FIG. 2 , the front access door  26  can take a bi-fold configuration where the door includes two hinge sets: a first hinge set attaching the door  26  to the frame  12  and a second hinge set attaching one panel of the door to another panel. Nevertheless, the front access door  26  can take other configurations such as a sliding door or a swinging door. Similarly, a rear access door  28  also mounts to the frame  12 . The rear access door  28  in the depicted embodiment also takes a hi-fold configuration; however, the rear access door can take other configurations such as those discussed with reference to the front access door  26 . Windows  32  can be provided on either door (only depicted on front door  26 ). The windows can include a tinted safety screen, which is known in the art. 
         [0017]    A control panel  40  is provided on the frame  12  adjacent the front door  26 . Control knobs and/or switches provided on the control panel  40  communicate with controls housed in a controls enclosure  42  that is also mounted to the frame  12 . The controls on the control panel  40  can be used to control operations performed in the unit  10  in a similar manner to controls used with known welding cell units. 
         [0018]    With reference to  FIG. 3 , the robot  14  mounts on a pedestal  50  that mounts on a support  52 . The robot  14  used in the depicted embodiment can be an ARC MATE® 100iBe robot available from FANUC Robotics America, Inc. Other similar robots can also be used. The robot  14  in the depicted embodiment is centered with respect to the welding tables  16  and  18  and includes eleven axes of movement. If desired, the pedestal  50  can rotate with respect to the support  52  similar to a turret. Accordingly, some sort of drive mechanism, e.g. a motor and transmission (not shown), can be housed in the pedestal  50  and/or the support  52  for rotating the robot  14 . 
         [0019]    With continued reference to the embodiment depicted in  FIG. 3 , a welding gun  60  attaches to a distal end of the robot arm  14 . The welding gun  60  can be similar to those that are known in the art. A flexible tube or conduit  62  attaches to the welding gun  60 . As more clearly seen in  FIG. 2 , consumable welding electrode wire  64 , which can be stored in a container  66 , is delivered to the welding gun  60  through the conduit  62 . A wire feeder  68 , which can be a PF 10 F-11 wire feeder available from The Lincoln Electric Company, attaches to the frame  12  to facilitate the delivery of welding wire  64  to the welding gun  60 . 
         [0020]    Even though the robot  14  is shown mounted to a base or lower portion of the frame  12 , if desired, the robot  14  can mount in a similar manner as the robot disclosed in U.S. Pat. No. 6,772,932. That is, the robot can mount to an upper structure of the frame and depend downwardly into the cell unit  10 . 
         [0021]    With reference back to the embodiment depicted in the figures, a power source  72  for the welding operation mounts to and rests on a platform  74  that is connected to and can be a part of the frame  12 . The power source  72  in the depicted embodiment is a PW 455 M (non STT) available from The Lincoln Electric Company; however, other suitable power sources can be used for the welding operation. A robot controller  76 , which controls the robot  14 , also rests and mounts on the platform  74 . The robot controller typically accompanies the robot  14 . 
         [0022]    Fork lift supports  80  defining fork lift receptacles  82  connect to a lower end of the frame  12 . As more clearly seen in  FIG. 3 , the fork lift supports  80  in the depicted embodiment are centered underneath the robot support  52  and thus the robot  14  to facilitate easy movement of the welding unit  10 . Even though the cell unit  10  is depicted with only two-way forklift access, the unit  10  can be easily modified to include four-way forklift access. 
         [0023]    With reference to  FIG. 5 , the connection between the first welding table  16  and a support  90  (also visible in  FIG. 2 ), to which both welding tables  16  and  18  attach, will be described. The connection between the second welding table  18  and the support  90  is the same as the first welding table; therefore, for the sake of brevity only the connection between the first welding table  16  and the support  90  will be described in detail. 
         [0024]    The welding table  16  is moveable with respect to the support  90  and with respect to the robot  14 . In the embodiment depicted in  FIG. 5 , the welding table  16  is movable about a first axis  92  and a second axis  94 , the first axis being perpendicular to the second axis. The first axis  92  is also parallel to (and in the depicted embodiment spaced above) a plane in which the support  90  resides. The second axis  94  is normal to a plane in which the welding table  16  resides. In the depicted embodiment, the second axis  94  is also spaced from an outermost edge of the support  90 . The welding table  16  can move in or about these two axes via motors that will be described in more detail below. Other assemblies and devices can also be provided for moving the welding tables, including pistons for linear movement (in either axis), gearing and transmissions for both linear (e.g. along rails) and rotational movement, as well as other known devices. 
         [0025]    In the embodiment depicted in  FIG. 5-8 , a first motor  100  is provided so that the welding table  16  can rotate about the first axis  92 . The first motor  100  connects to a power supply (not shown) for the unit  10  via a power cord  102 . The first motor  100  mounts to a motor mount  104  and the motor mount connects to the support  90  via bolts  106 . In the depicted embodiment, the motor mount  104  includes a base portion  108  and an upright portion  112  that is disposed normally to the base portion. Web portions  114  (two are shown in  FIG. 6 ) are spaced from one another and interconnect the base portion  108  and the support portion  112 . The web portions  114  are spaced from one another an adequate distance so that the first motor  100  can be received between the base portions. The support portion  112  of the bracket  104  includes an opening to receive an output shaft (not visible) of the first motor  100 . The output shaft of the first motor connects to a support plate  120  such that the support plate can rotate in or about the first axis  92 . 
         [0026]    A second motor mount  124  that has the same configuration as the first motor mount  104  connects to the support plate  120  so that it can also rotate in or about the first axis  92 . As more clearly seen in  FIG. 8 , the second motor mount  124  attaches to the support plate  120  via bolts (or other conventional fasteners)  126 . The second motor mount  124  includes a base portion  128  through which the bolts  126  extend. The second motor mount  124  also includes a support (similar to the upright portion  112  of the first motor mount  124 )  132  that extends normally from the base  128 . A pair of webs  134  interconnect the support  132  to the base  128 . The webs  134  are spaced from one another such that a second motor  140  is receive between the webs  134 . The support  132  of the motor mount  124  includes an opening through which an output shaft (not visible) of the second motor  140  is received to operatively connect the second motor  140  to the welding table  16 . Power is delivered to the second motor  140  via a power cord  142  that connects to a power source (not shown) for the unit  10 . 
         [0027]    Accordingly, the welding table  16  rotates about the first axis  92  via the first motor  100  and rotates about the second axis  94  via the second motor  140 . As mentioned above, the first axis  92  is parallel to and spaced above a plane in which the support  90  resides. The second axis  94  is spaced from an outer edge of the support  90  as measured along the first axis  92 . Movement in the first axis  92  can be limited to prevent damage to the second motor  140  and the welding table  16 . The first motor  100  is operatively connected to the welding table  16  via first motor mount  104  and the second motor mount  124 . 
         [0028]    As more clearly seen in  FIG. 3 , the first welding table  16  and the second welding table  18  are spaced from one another and aligned along first axis  92 , in that they both reside the same radial distance from the first axis  92 . Also, the first and second welding tables  16  and  18  each rotate about an axis that is normal to the axis in which the welding table resides. Even though only two welding tables are depicted, a fewer or greater number of welding tables can be provided. 
         [0029]    As discussed above, the first and second welding tables  16  and  18  attach to the support  90 . As more clearly seen in  FIGS. 3 and 4 , the support  90  includes a central opening  150  through which the pedestal  50  extends (see  FIG. 3 ). As depicted in  FIG. 4 , the support  90  rotates about a central axis  152 , accordingly, rotation of the support  90  also results in movement of the welding table about at least one axis, i.e. axis  152 . In the depicted embodiments the welding tables  16  and  18  are spaced from one another equidistantly from the central axis  152 . The robot  152  can also rotate in or about the central axis  152 . A seen in  FIG. 3 , the support  50 , which can include or connect to a turret, is also centered on the central axis  152 . 
         [0030]    When the unit  10  is in use and with reference to  FIG. 2 , a part  24  can be loaded onto the second welding table  18  while a welding operation is being performed on the first part  22  located on the first welding table  16 . In the depicted embodiment, shields  160  are provided on the support  90  between the respective welding tables on opposite sides of the robot  14 . After the welding operation on the first welding table  16  has been completed, the support  90  can rotate in a manner such that the second welding table  18  now occupies the location or space that the first welding table  16  had occupied. The welding operation can then be performed on the second piece  24 . The process can then be repeated. 
         [0031]    A receptacle  168  for receiving torch conditioning devices, such as a reamer, is provided on the support  90  for cleaning of the welding gun  60  between welding procedures. A touch probe (not depicted) can also be provided on the frame and/or the support  90 . The touch probes serves as a tool point reference. The touch probe can be used on a datum to allow for reprogramming of the robot. Such torch conditioning and touch probe devices are known in the art. 
         [0032]    A welding cell unit and a welding table assembly have been described with reference to the above-mentioned embodiments and alternatives thereof. Many modifications and alterations to those embodiments disclosed readily suggest themselves to those skilled in the art upon reading and understanding the detailed description. For example, the welding table assembly can be used with other configurations of welding cell units, for example, the welding cell unit described in co-pending application Ser. No. 10/992,890, filed on Nov. 19, 2004, which is incorporated by reference herein. The invention is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims and the equivalents thereof.