Abstract:
An automated system for adapting a gripper to conform to parts having various configurations is disclosed herein. The gripper includes clamp pads having clamp surfaces for clamping protrusions on the parts. The automated system includes an actuator coupled to the gripper, a transfer mechanism engaging the actuator and moveable in response to actuations by the actuator, and a clamp block coupled to and moveable with the transfer mechanism.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of U.S. Ser. No. 12/839,805, filed Jul. 20, 2010, which is hereby incorporated by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to robotic finishing systems and, more particularly, to direct clamp grippers and part adapter systems for grippers. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    Metalworking of cast metal articles such as prosthetic knee implants typically requires surface finishing such as buffing, polishing, deburring, grinding and satin finishing. Traditionally, these finishing steps were performed by hand. More recently, however, automated processing replaced most manual operations. As compared to manual finishing, automated finishing provides greater efficiency, precision, and safety. 
         [0005]    An important aspect of robotic finishing knee implants is the need to manipulate the implant to expose all surfaces to a finishing device such as a wheel or belt. To accomplish this, the implant must be held by the robot and maneuvered to various orientations relative to the finishing device. Importantly, the robot must hold the implant against the finishing device with pressure without marring the surface of the implant when picking it up or putting it down. 
         [0006]    One technique for enabling a knee implant to be picked up and manipulated by a robot in a finishing operation is to mount the knee implant to a metal support bar. In this technique, the knee implant is fixed to a central region of a metal bar through the use of fasteners such as screws. The bar laterally extends beyond the both outboard edges of the knee implant to provide two graspable handles for the robot. The robot may then use jaws to clamp onto one handle of the bar and manipulate the knee implant relative to the finishing device. The knee implant and bar assembly may then be set down while the robot repositions its jaws to the other graspable handle of the bar. The knee implant may then be further manipulated relative to the finishing device. Mounting a knee implant to a support bar is labor intensive and involves significant costs associated with the support bars. 
         [0007]    A second technique for enabling robotic manipulation of a knee implant is to secure a gripper to a robot having jaws. The gripper allows the robot to directly clamp the knee implant via actuation of the jaws. One type of a conventional gripper includes two opposing clamp bars that clamp onto two posts extending from an inner surface of the knee implant. The robot positions the clamp bars normal to the outboard edges of the knee implant on opposite sides of the two posts, and then brings the clamp bars together to clamp the posts. The robot closes its jaws to bring the clamp bars together and opens its jaws to move the clamp members apart. When clamping the posts, the clamp bars extend across a cruciate gap separating two condyles of the knee implant from which the two posts extend. Using a gripper such as the one described above for finishing knee implants requires manually finishing the cruciate gap obstructed by the clamp bars during automated finishing. 
         [0008]    Thus, there is a need for a finishing system that enables the direct clamping of knee implants while providing maximized part clearance. 
       SUMMARY 
       [0009]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0010]    An automated system for adapting a gripper to conform to parts having various configurations is disclosed herein. The gripper includes clamp pads having clamp surfaces for clamping protrusions on the parts. The automated system includes an actuator coupled to the gripper, a transfer mechanism engaging the actuator and moveable in response to actuations by the actuator, and a clamp block coupled to and moveable with the transfer mechanism. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0012]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0013]      FIG. 1  is a plan view of a robotic finishing system according to the principles of the present disclosure; 
           [0014]      FIG. 2  is a perspective view of a part staging fixture according to the principles of the present disclosure supporting a knee implant; 
           [0015]      FIG. 3  is a planar view of the part staging fixture of  FIG. 2  supporting a knee implant; 
           [0016]      FIG. 4  is a perspective view of a direct clamp gripper according to the principles of the present disclosure clamping a post of a knee implant; 
           [0017]      FIG. 5  is a perspective view of the direct clamp gripper of  FIG. 4  and a knee implant, with the gripper clamping a different post of the knee implant; 
           [0018]      FIG. 6  is an exploded perspective view of the direct clamp gripper of  FIG. 4 ; 
           [0019]      FIG. 7  is a sectional view of the direct clamp gripper of  FIG. 4  and a knee implant, with clamp pads of the gripper positioned to clamp the post; 
           [0020]      FIG. 8  is a sectional view of the direct clamp gripper of  FIG. 4  and a knee implant, with the clamp pads of the gripper positioned to release the post; 
           [0021]      FIG. 9  is a perspective view of a part regrip fixture according to the principles of the present disclosure clamping notches in a knee implant; 
           [0022]      FIG. 10  is a side view of a knee implant being transferred between the direct clamp gripper of  FIG. 4  and the part regrip fixture of  FIG. 9 ; 
           [0023]      FIG. 11  is a sectional view of the part regrip fixture of  FIG. 9  and a knee implant, with tabs of the regrip fixture positioned to engage the notches; 
           [0024]      FIG. 12  is a sectional view of the part regrip fixture of  FIG. 9  and a knee implant, with tabs of the regrip fixture positioned to release the notches; 
           [0025]      FIG. 13  is a perspective view of a direct clamp gripper according to the principles of the present disclosure clamping a post of a knee implant; 
           [0026]      FIG. 14  is a perspective view of a direct clamp gripper including a part adapter system according to the principles of the present disclosure, the gripper releasing a part adapter according to the principles of the present disclosure; 
           [0027]      FIG. 15  is a perspective view of the direct clamp gripper of  FIG. 14  clamping a part adapter according to the principles of the present disclosure; 
           [0028]      FIG. 16  is an exploded perspective view of the direct clamp gripper of  FIG. 14 ; 
           [0029]      FIG. 17  is a perspective view of a portion of the direct clamp gripper of  FIG. 14  clamping a post of a first knee implant and conforming to an inner surface of the first knee implant; 
           [0030]      FIG. 18  is a perspective view of a portion of the direct clamp gripper of  FIG. 14  clamping a post of a second knee implant and clamping a first part adapter, the first part adapter adapting the gripper to conform to an inner surface of the second knee implant; 
           [0031]      FIG. 19  is a perspective view of a portion of the direct clamp gripper of  FIG. 14  clamping a post of a third knee implant and clamping a second part adapter, the second part adapter adapting the gripper to conform to an inner surface of the third knee implant; 
           [0032]      FIG. 20  is a perspective view of an adapter nest supporting a plurality of part adapters according to the principles of the present disclosure; 
           [0033]      FIG. 21  is a perspective view of the direct clamp gripper of  FIG. 4  positioned above one of the part adapters supported by the adapter nest of  FIG. 20 ; 
           [0034]      FIG. 22  is a perspective view of a direct clamp gripper including a part adapter system according to the principles of the present disclosure; and 
           [0035]      FIG. 23  is a perspective view of an adapter nest engaging a plurality of part adapters according to the principles of the present disclosure. 
       
    
    
       [0036]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0037]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0038]    Referring now to  FIG. 1 , a robotic finishing system  10  used for finishing parts such as knee implants is illustrated. The system  10  includes a part staging fixture  12 , a robot  14 , a direct clamp gripper  16  coupled to the robot  14 , a wheel finishing device  18 , a belt finishing device  20 , and a part regrip fixture  22 . The robot  14  may be a FANUC M710iC 6-Axis robot with a 110-pound payload. The finishing devices  18 ,  20  may include 5 horsepower dual stacked buff heads or ultra-light front floating heads. The system  10  may include more or less finishing devices. 
         [0039]    In operation, the robot  14  picks up a knee implant from the part staging fixture  12  and manipulates the implant relative to the finishing devices  18 ,  20  to perform buffing, polishing, and the like. To expose all surfaces of the implant to the finishing devices  18 ,  20 , the robot  14  transfers the part to the regrip fixture  22  and regrips the part from an opposite side. Finishing operations are then continued. 
         [0040]    Referring now to  FIG. 2 , the staging fixture  12  may support a knee implant  24  both before and after the implant  24  is finished in the system  10 . Although a knee implant is used throughout this description as an example of the part to be finished, the present disclosure is not limited to tooling for finishing knee implants. 
         [0041]    The staging fixture  12  includes a mounting base block  26 , a support block  28 , a part nesting block  30 , and an actuator  32 . The mounting base block  26  includes holes  34  in which fasteners may be inserted to fix the staging fixture  12  to, for example, a bedplate. The blocks  26 ,  28  may include holes (not shown) in which fasteners may be inserted to fix the support block  28  to the mounting base block  26 . The support block  28  includes mounting surfaces  36  on which the part nesting block  30  and the actuator  32  are mounted. The mounting surfaces  36  may include holes (not shown) in which fasteners may be inserted to mount the part nesting block  30  and the actuator  32  to the support block  28 . 
         [0042]    The part nesting block  30  includes a mounting portion  38  and an engaging portion  40 . The mounting portion  38  has a rectangular shape and includes holes  42  in which fasteners may be inserted to mount the part nesting block  30  to the support block  28 . The engaging portion  40  has a hexagonal shape providing outer surfaces  43 . A clamp pad  44  is attached to an end of the engaging portion  40  via fasteners inserted through holes  45  in the clamp pad  44 . A proximity sensor  46  is attached to an outer surface  47  of the engaging portion  40  via a sensor bracket  48 . The actuator  32  may be a compact pneumatic cylinder that is single acting with a spring return or double acting with a compressed air return. 
         [0043]    The implant  24  includes fingers or condyles  50  and a cruciate gap  52  disposed between and separating the condyles  50 . The condyles  50  include inner surfaces  54 , extraction notches  56  located at outboard edges of the implant  24 , and one or more protrusions  58  extending from the inner surfaces  54  adjacent to the extraction notches  56 . The outer surfaces  43  of the part nesting block  30  are shaped to substantially conform to the inner surfaces  54  of the implant  24 . The protrusions  58  may be posts, as shown, that are integrally formed with the implant  24  or threaded into holes (not shown) provided in the implant  24 . Alternatively, the protrusions  58  may be a single rectangular box disposed between the condyles  50 . 
         [0044]    Referring now to  FIG. 3 , inner components of the staging fixture  12  will now be described. The inner components of the staging fixture  12  include a coupler or pushrod  60  and a clamp pad  62 . The pushrod  60  couples the clamp pad  62  to the actuator  32 . The pushrod  60  and the clamp pad  62  are slideable within a bore  63  extending through the support block  28  and the part nesting block  30 . The clamp pad  62  includes a clamp surface  64  opposing a clamp surface  66  on the clamp pad  44 . 
         [0045]    Referring to  FIGS. 2 and 3 , operation of the staging fixture  12  will now be described. The staging fixture  12  engages the inner surfaces  54  of the implant  24  to locate the implant  24 , and engages one of the protrusions  58  on the implant  24  to grip the implant  24 . The implant  24  may be loaded onto the staging fixture  12  and unloaded from the staging fixture  12  either manually or using a gantry crane (not shown). The outer surfaces  43  of the part nesting block  30  engage the inner surfaces  54  of the implant  24  to locate the implant  24  relative to the staging fixture  12 . 
         [0046]    The staging fixture  12  grips the implant  24  by actuating the pushrod  60  toward the clamp pad  44  to engage the clamp surfaces  64 ,  66  on the clamp pads  44 ,  62  with one of the protrusions  58  on the implant  24 . The staging fixture  12  may grip the implant  24  when the proximity sensor  46  detects the presence of the implant  24 . The staging fixture  12  releases the implant  24  by actuating the pushrod  60  away from the clamp pad  44  to disengage the clamp surfaces  64 ,  66  from one of the protrusions  58 . 
         [0047]    Gripping components and operation of the staging fixture  12  may be identical to those of the gripper  16  or similar to those of the gripper  16  with only minor differences such as sizing. The gripping components of the staging fixture  12  may be sized smaller than the gripping components of the gripper  16 , as the staging fixture  12  need not be able to withstand high loads exerted on the implant  24  during finishing. In view of the foregoing, the discussion below regarding the gripping components and operation of the gripper  16  also applies to the staging fixture  12 . 
         [0048]    Referring to  FIGS. 4 through 6 , the gripper  16  includes a first adapter  68 , an actuator  70 , a second adapter  72 , dowel pins  74 , a spacer block  76 , a support  78 , clamp pads  80 ,  82 , and cover plates  83 . The clamp pads  80 ,  82  include clamp surfaces  84 ,  86 , respectively, that are shaped to substantially conform to the contour of the protrusions  58  of the implant  24 . Minor differences between the clamp surfaces  84 ,  86  and the perimeter surfaces of the protrusions  58  may be allowed for ease of manufacture. For example, the perimeter surfaces of the protrusions  58  may taper inward toward the respective ends of the protrusions  58 , while the clamp surfaces  84 ,  86  may be straight. 
         [0049]    The first adapter  68  may be a cylindrical plate having a bore  87  extending through the first adapter  68  and may include holes  88 ,  90 , and  92  extending at least partially through the first adapter  68 . The holes  88 ,  90 , and  92  may be threaded, unthreaded, straight, countersunk, and/or counterbored depending on the fastener type to be inserted therein. Fasteners  94  are inserted into the holes  88  to couple the gripper  16  to the robot  14  of  FIG. 1 . The fasteners  94  may be socket head screws, as shown, and the holes  88  may be counterbored. 
         [0050]    The actuator  70  may be a single or double acting compact pneumatic cylinder having a rectangular block shape and including a piston  96  therein. The piston  96  includes a shaft  98  including a threaded hole  100  therein. The actuator  70  further includes a bore  102  extending partially through the actuator  70  and holes  104  for fixing the actuator  70 . The piston  96  is slideable within the bore  102 , and travel of the piston  96  may be limited by the housing of the actuator  70 . The holes  104  may be through holes. 
         [0051]    The second adapter  72  may be a rectangular plate including a bore  106  and holes  107 ,  108 ,  109 , and  110  extending at least partially through the second adapter  72 . Fasteners  112  are inserted into the holes  92 ,  104 , and  108  to couple the second adapter  72  and the actuator  70  to the first adapter  68 . The fasteners  112  may be socket head screws, as shown, and the holes  108  may be counterbored through holes receiving the socket head screws. Dowell pins  74  are inserted into holes  110  and  90 . 
         [0052]    The spacer block  76  includes a bore  114  and holes  116 ,  118  extending at least partially through the spacer block  76 . The holes  116  may be unthreaded. Dowell pins  120  are inserted into the holes  116  to align the bore  114  relative to the bores  102  and  106 . A coupler or pushrod  122  is slideable within the bore  114  and couples end clamping components of the gripper  16  to the piston  96 . The pushrod  122  includes a shaft  124  and a flat surface  126  including holes  128 ,  130  for receiving fasteners such as screws and pins. The shaft  124  of the pushrod  122  is threaded into the hole  100  of the piston  96 , and a nut  132  is threaded onto the pushrod  122  to prevent the shaft  124  from backing out of the hole  100 . The nut  132  may be a hex jam nut, as shown. 
         [0053]    The support  78  may include a mounting portion  133  including holes  134  and an engaging portion  135  including an opening  136 , holes  138 , holes  140 , and an enclosed end  139  including holes  140 , and outer surfaces  142 . The opening  136  exposes or provides access to the clamp surfaces  84 ,  86  of the clamp pads  80 ,  82 . The engaging portion  135  may have an octagonal shape providing the outer surfaces  142  of the engaging portion  135  such that the outer surfaces  142  are shaped to substantially conform to the inner surfaces of the implant  24 . The outer surfaces  142  may include a horizontal surface that is horizontal relative to ground, an angled surface that is oriented at a reflex angle relative to the horizontal surface, and a side surface that is oriented at a right angle relative to the horizontal surface. 
         [0054]    Fasteners  144 , such as screws, are inserted into holes  145  in the clamp pads  80  and into the holes  128  in the pushrod  122  to attach the clamp pads  80  to the pushrod  122 . When assembled, the surfaces of the clamp pads  80  receiving the fasteners  144  may be recessed relative to the outer surfaces  142  of the support  78  to avoid contacting the implant  24  as the clamp pads  80  are actuated within the opening  136 . Dowell pins  146  are inserted into holes  147  in the clamp pads  80  and into the holes  130  in the pushrod  122  to position the clamp pads  80  relative to the pushrod  122 . Fasteners  148 , such as screws, attach the cover plates  83  to the support  78 . The cover plates  83  may cover a portion of the opening  136  that does not need to be accessible after the clamp pads  80 ,  82  are assembled. 
         [0055]    Fasteners  150  are inserted into the holes  140  in the enclosed end  139  of the support  78  and into holes  153  in the clamp pads  82  to attach the clamp pads  82  to the support  78 . The fasteners  150  may be screws, as shown, the holes  140  may be unthreaded, and the holes  153  may be threaded. Fasteners  152  are inserted into the holes  109 ,  118 , and  134  to attach the spacer block  76  and the support  78  to the second adapter  72 . The fasteners  152  may be socket head screws, as shown, and may be used in conjunction with washers  154 . 
         [0056]    Referring now to  FIGS. 7 and 8 , inner detail of the gripper  16  is illustrated. The actuator  70  includes a cavity  156  to which the bore  102  extends. Travel of the piston  96  may be limited due to contact between the head of the piston  96  and the cavity  156 . The support  78  includes bores  158 ,  160  and a bushing  162 . The bore  158  may have a greater diameter than the bore  160  to accommodate the bushing  162 . The pushrod  122  slides within the bore  160  and the bushing  162 . 
         [0057]    Referring again to  FIGS. 4 through 8 , operation of the gripper  16  will now be discussed. The gripper  16  engages the inner surfaces  54  of the implant  24  and clamps one of the protrusions  58  on the implant  24  to hold the implant  24  during finishing. Engaging the inner surfaces  54  of the implant  24  locates the implant  24  relative to the gripper  16  and facilitates clamping only one of the protrusions  58  by reducing stress levels in the implant  24  during finishing. Clamping only one of the protrusions  58  avoids the need to extend the part nesting block  30  across the cruciate gap  52  of the implant  24  when the gripper  16  clamps the implant  24 , enabling automated finishing of the cruciate gap  52 . 
         [0058]    When gripping the implant  24 , the robot  14  of  FIG. 1  positions the clamp pads  80 ,  84  of gripper  16  on opposite sides of one of the protrusions  58  of the implant  24 . The portion of the gripper  16  that engages the implant  24 , including the outer surfaces  142  of the part nesting block  30 , are symmetric about a longitudinal mid-plane extending through the gripper  16 . This enables the gripper  16  to clamp either of the protrusions  58  on the implant  24 , as shown in  FIGS. 4 and 5 , without being rotated to engage the outer surfaces  142  of the part nesting block  30  with the inner surfaces  54  of the implant  24 . In turn, the robot  14  does not need the ability to rotate the gripper  16 , which may reduce costs associated with the robot  14 . 
         [0059]    When the clamp pads  80 ,  82  are positioned on opposite sides of one of the protrusions  58  on the implant  24 , the actuator  70  actuates the piston  96  to move the pushrod  122  and the clamp pad  80  toward the clamp pad  82 . Travel of the piston  96 , the pushrod  122 , and the clamp pad  80  in this direction is stopped when the clamp surfaces  84 ,  86  of the clamp pads  80 ,  82  engage the protrusions  58 , as shown in  FIG. 7 . The actuator  70  holds the clamp pad  80  in this position to hold the implant  24  in the gripper  16 . When the clamp pads  80 ,  82  are not positioned about an object, travel of the piston  96 , the pushrod  122 , and the clamp pad  80  in this direction is limited by contact between the clamp pads  80 ,  82 . 
         [0060]    When releasing the implant  24 , the actuator  70  actuates the piston  96  to move the pushrod  122  and the clamp pad  80  away from the clamp pad  82 . Travel of the piston  96 , the pushrod  122 , and the clamp pad  80  in this direction is limited by contact between the head of the piston  96  and the bottom of the cavity  156  in the actuator  70 , as shown in  FIG. 8 . However, the actuator  70  may stop travel in this direction prior to encountering this limit. 
         [0061]    The amount by which the clamp pads  80 ,  82  may be separated to accommodate various protrusions  58  on the implant  24  is governed by the travel limit in the releasing direction. However, the clamp pads  80 ,  82  may be shaped and sized to conform to the shapes and sizes of the protrusions  58  on the implant  24 . In addition, the depth to which the pushrod  122  is threaded in the piston  96  may be adjusted to accommodate protrusions having various shapes and sizes. 
         [0062]    Since the clamp pads  80 ,  82  may be detached from the pushrod  122 , the clamp pads  80 ,  82  may be replaced with clamp pads having different shapes or sizes to accommodate the protrusions  58  when gripping or releasing. In addition, the clamp pads  80 ,  82  may be replaced as the clamp surfaces  84 ,  86  on the clamp pads  80 ,  82  wear out. Replacing the clamp pads  80 ,  82  and/or varying the threaded depth of the pushrod  122  in the piston  96  to accommodate the protrusions  58  may save costs relative to other modifications to the gripper  16 . 
         [0063]    Referring to  FIG. 9 , the regrip fixture  22  includes a base block  164 , an actuator  166 , adapters  168 , and fingers  170 . The base block  164  may includes holes, such as those shown, in which fasteners may be inserted to fix the base block  164  to, for example, a bedplate. The actuator  166  includes slide tracks  172  to which the adapters  168  attach. The adapters  168  may be attached to the tracks  172  using fasteners, such as the socket head screws shown. The fingers  170  include tabs  174  and are attached to the adapters  168 . The fingers  170  may be attached to the adapters  168  using fasteners, such as socket head screws. The tabs  174  are shaped and sized to be inserted into and engage the notches  56  in the implant  24 . 
         [0064]    With additional reference to  FIGS. 10 through 12 , operation of the regrip fixture  22  will now be discussed. The regrip fixture  22  holds the implant  24  by the notches  56  in the implant  24  while the robot  14  switches from holding one of the protrusions  58  to holding another one of the protrusions  58 . To enable the regrip fixture  22  to grip the implant  24 , the robot  14  positions the notches  56  in the implant  24  adjacent to the tabs  174  of the fingers  170 , as shown in  FIG. 10 . 
         [0065]    When gripping the implant  24 , the regrip fixture  22  actuates the adapters  168  and the fingers  170  along the length of the track  172  to move the tabs  174  on the fingers  170  toward the notches  56  in the implant  24 . The regrip fixture  22  stops actuating the tabs  174  in this direction when the tabs  174  bottom out in the notches  56 , as shown in  FIG. 11 . In this position, the engagement between the tabs  174  on the fingers  170  and the notches  56  in the implant  24  holds the implant  24 . While the regrip fixture  22  holds the implant  24 , the robot  14  moves to the opposite side of the implant  24  to grab another one of the protrusions  58  on the implant  24 . 
         [0066]    When releasing the implant  24 , the regrip fixture  22  actuates the adapters  168  and the fingers  170  along the length of the track  172  to move the tabs  174  on the fingers  170  away from the notches  56  in the implant  24 . The regrip fixture  22  stops actuating the tabs  174  in this direction when the tabs  174  are removed from the notches  56 , as shown in  FIG. 12 . Travel in this direction is limited by the travel limits of the actuator  166 . However, the adapters  168  and/or the fingers  170  may be modified to accommodate various implant shapes and sizes. 
         [0067]    Referring now to  FIG. 13 , a direct clamp gripper  16 ′ is substantially similar to the direct clamp gripper  16  such that only differences between the grippers  16 ,  16 ′ will now be discussed. In contrast to the gripper  16 , the portion of the gripper  16 ′ that engages the implant  24  is not symmetric about a longitudinal mid-plane extending through the gripper  16 ′. Thus, the gripper  16 ′ must be rotated as the gripper  16 ′ transitions between clamping the protrusions  58  on the implant  24 . However, the gripper  16 ′ may require less material and less machining operations as compared to the gripper  16 , thereby saving costs associated with the gripper  16 ′. 
         [0068]    The gripper  16 ′ includes an engaging portion  175  including a flat surface  176 , an opening  177 , and an enclosed end  178 . The engaging portion  175  has a hexagonal shape rather than the octagonal shape of the engaging portion  135  of  FIG. 6 . The flat surface  176  extends between two of the surfaces  142 ′ shown as parallel and vertical in  FIG. 13 , and the flat surface  176  is opposite one of the surfaces  142 ′ shown as horizontal in  FIG. 13 . The flat surface  176  may be positioned in the vertical direction of  FIG. 13  such that the height of the two parallel surfaces  142 ′ is equal to the height of the two corresponding surfaces  142  of  FIG. 6 . The opening  177  extends only partially through the engaging portion  175 , as the opening  177  does not extend through the flat surface  176 . The enclosed end  178  includes holes  179  that are in different positions relative to the holes  140  in the enclosed end  139  of  FIG. 6 . This difference in the positions of the holes  140 ,  179  is due to the geometric differences between the engaging portions  135 ,  175 . 
         [0069]    Referring now to  FIGS. 14 and 15 , a direct clamp gripper  16 ″ is substantially similar to the direct clamp gripper  16  such that only differences between the grippers  16 ,  16 ″ will now be discussed. The gripper  16 ″ includes at least a portion of a part adapter system  180  for adapting the gripper  16 ″ to conform to parts, such as knee implants, having various shapes and sizes. The part adapter system  180  includes an actuator  182 , a lever  184 , a pushrod  186 , a clamp block  188 , and a part adapter  190 . The gripper  16 ″ may release the part adapter  190 , as shown in  FIG. 14 , and may clamp the part adapter  190 , as shown in  FIG. 15 . 
         [0070]    The actuator  182  includes a piston  192 . The actuator  182  may be a single acting pneumatic cylinder in which pressurized air translates the piston  192  in one direction, and a return mechanism, such as a spring, actuates the piston  192  in the opposite direction. Alternatively, actuator  182  may be a double acting pneumatic cylinder in which pressurized air actuates the piston  192  in two directions. The actuator  182  is sized to provide sufficient force to clamp the part adapter  190 . 
         [0071]    A clevis  194  couples the lever  184  to the piston  192  of the actuator  182 . The actuator  182  may be extended to rotate the lever  184  about a pivot  196  in a direction away from the pushrod  186 . The actuator  182  may be retracted to rotate the lever  184  about the pivot  196  in a direction toward the pushrod  186 . 
         [0072]    The lever  184  abuts the pushrod  186  and is uncoupled from the pushrod  186 . The lever  184  may abut a shaft collar  198  coupled to the pushrod  186 . The lever  184  pushes the pushrod  186  when the lever  184  is rotated about the pivot  196  in a direction toward the pushrod  186 . A biasing mechanism  199  maintains engagement between the lever  184  and the pushrod  186  when the lever  184  is rotated in a direction away from the pushrod  186 . The biasing mechanism  199  includes a spring  200  captured between the shaft collar  198  and a bearing  202 . 
         [0073]    The bearing  202  and a bearing  204  are fixed within a support  78 ″ of the gripper  16 ″. The pushrod  186  is supported by and translatable through the bearings  202 ,  204 . The clamp block  188  is coupled to the pushrod  186  adjacent the bearing  204 . The pushrod  186  moves the clamp block  188  when the pushrod  186  is translated through the bearings  202 ,  204 . 
         [0074]    The clamp block  188  includes an overhang  206  sized and shaped to substantially conform to a groove  208  in the part adapter  190 . The gripper  16 ″ releases the part adapter  190  when the overhang  206  of the clamp block  188  disengages the groove  208  in the part adapter  190 , as shown in  FIG. 14 . The gripper  16 ″ clamps the part adapter  190  when the overhang  206  of the clamp block  188  engages the groove  208  in the part adapter  190 , as shown in  FIG. 15 . The groove  208  has an open end  209  through which the clamp block  188  is received. 
         [0075]    The actuator  182  may be extended to release the part adapter  190 , as shown in  FIG. 14 . When the actuator  182  is extended, the lever  184  rotates about the pivot  196  in a direction away from the pushrod  186 . This allows the biasing mechanism  199  to translate the pushrod  186  in a direction away from the part adapter  190 , thereby moving the clamp block  188  out of engagement with the part adapter  190 . 
         [0076]    The actuator  182  may be retracted to clamp the part adapter  190 , as shown in  FIG. 15 . When the actuator  182  is retracted, the lever  184  rotates about the pivot  196  in a direction toward the pushrod  186 . This causes the lever  184  to push the pushrod  186  in a direction toward the part adapter  190 , thereby moving the clamp block  188  into engagement with the part adapter  190 . 
         [0077]    With additional reference to  FIG. 16 , the gripper  16 ″ will now be described in greater detail. The actuator  182  further includes a housing  210  having a rectangular block shape and holes  212  extending through the housing  210  along the length of the housing  210 . The piston  192  of the actuator  182  includes a hole  216  partially extending through the piston  192  along the length of the piston  192 . A shaft  218  threads into the hole  216 , and a nut  220  threads onto the shaft  218 . 
         [0078]    A second adapter  72 ″ of the gripper  16 ″ includes an extension block  222  to which the housing  210  of the actuator  182  is mounted. The extension block  222  includes a hole  224  and holes  226  that extend through the extension block  222 . The hole  224  receives the piston  192  of the actuator  182  and may be shaped similar to a key hole. The holes  226  receive fasteners  228 , such as screws, which fasten the actuator  182  to the extension block  222  of the second adapter  72 ″. 
         [0079]    The clevis  194  includes a threaded hole (not shown) extending at least partially through the cylindrical portion of the clevis  194  such that the clevis  194  can be threaded onto the shaft  218  after the nut  220  is threaded onto the shaft  218 . The nut  220  may be tightened against the clevis  194  such that the nut  220  acts as a lock nut by maintaining the position of the clevis  194  on the shaft  218 . The clevis  194  includes holes  230  extending through the U-bracket portion of the clevis  194 . 
         [0080]    The lever  184  includes a first end  232 , a second end  234 , a slot  236  adjacent to the first end  232 , a hole  238  between the first end  232  and the second end  234 , and a rounded surface  240  adjacent to the second end  234 . A fastener  242 , such as a pin, is inserted through the holes  230  in the clevis  194  and through the slot  236  in the lever  184  to couple the clevis  194  to the lever  184 . 
         [0081]    A bearing  244 , such as a hardened steel bearing, is pushed into the hole  238  in the lever  184 . The bearing  244  engages the pivot  196  about which the lever  184  rotates. The distance between the first end  232  of the lever  184  and the hole  238  in the lever  184  is greater than the distance between the hole  238  in the lever  184  and the second end  234  of the lever  184 . This creates a moment arm about the pivot  196 , amplifying the force transmitted from the first end  232  of the lever to the second end  234  of the lever  184 , thereby allowing the actuator  182  to be sized smaller. The rounded surface  240  of the lever  184  abuts the pushrod  186 . 
         [0082]    A spacer block  76 ″ of the gripper  16 ″ includes an extension block  246  and a hole  248 . The extension block  246  of the spacer block  76 ″ adjoins the extension block  222  of the second adapter  72 ″ and includes holes  250 . The hole  248  in the spacer block  76 ″ extends laterally through the extension block  246 . Sleeves  252  are inserted into the hole  248  to provide a slight clearance or line-to-line fit between the sleeves  252  and the bearing  244  in the hole  238  in the lever  184 . A fastener  254 , such as a pin, is inserted through the sleeves  252  and the bearing  244  to form the pivot  196  about which the lever  184  rotates. A retaining clip  256  retains the fastener  254  in the sleeves  252  and in the bearing  244 . Fasteners  258 , such a screws, are inserted into the holes  226 ,  250  to fasten the extension block  246  of the spacer block  76 ″ to the extension block  222  of the second adapter  72 ″. 
         [0083]    The shaft collar  198  includes a hole  260  that receives a set screw (not shown), which couples the shaft collar  198  to the pushrod  186 . The pushrod  186  includes a flat surface  262 . The clamp block  188  includes a hole  264  extending through the clamp block  188 , and the overhang  206  of the clamp block  188  includes an underside surface  266 . A set screw (not shown) is driven into the hole  264  and against the flat surface  262  to couple the clamp block  188  to the pushrod  186 . 
         [0084]    The support  78 ″ of the gripper  16 ″ includes a channel  270 , a recess  274  above the channel  270 , and holes  276  in the recess  274 . The clamp block  188  moves within the channel  270  as the actuator  182  extends and retracts. A cover plate  278  is placed in the recess  274  to cover the clamp block  188  moving in the channel  270 . The cover plate  278  includes holes  280  through which fasteners  282 , such as screws, are inserted to fasten the cover plate  278  to the support  78 ″. 
         [0085]    The support  78 ″ of the gripper  16 ″ is configured to engage a knee implant without using the part adapter system  180 . To this end, the support  78 ″ includes outer surfaces  284  that substantially conform to the inner surfaces of a knee implant. As with the gripper  16 , the support  78 ″ of the gripper  16 ″ also includes outer surfaces  142 ″ that substantially conform to inner surfaces of a knee implant. However, the outer surfaces  142  only extend around a portion of the support  78 ″, and the outer surfaces  284  extend around the remaining portion of the support  78 ″. 
         [0086]    The support  78 ″ of the gripper  16 ″ also includes adaptations that facilitate clamping the part adapter  190  onto the gripper  16 ″. In this regard, the support  78 ″ includes a groove  286  having a sloped surface  288 , and includes holes  290  extending across the groove  286 . The groove  286  receives a portion of the part adapter  190 . The holes  290  receive a stop  292 , such as a pin, which prevents the part adapter  190  from backing out of the groove  286  when the clamp block  188  is moved to engage the groove  208  in the part adapter  190 . In this manner, the stop  292  maintains engagement between the part adapter  190  and the clamp block  188 . 
         [0087]    The part adapter  190  is toothbrush-shaped and includes a first flat surface  294  adjacent the groove  208 , a second flat surface  296 , a first projection  298 , and a second projection  300 . The first projection  298  and the second projection  300  partially define outer surfaces  302  that extend around the outer perimeter of the part adapter  190  and that substantially conform to inner surfaces of a knee implant. The knee implant to which the outer surfaces  302  of the part adapter  190  conform has a size and/or shape different from that of the knee implant to which the outer surfaces  284  of the support  78 ″ conform, as discussed below. 
         [0088]    A fastener  304 , such as a screw, and fasteners  305 , such as pins, align and couple a hook member  306  to a base portion  307  of the part adapter  190 . Although the hook member  306  is shown separate from the part adapter  190 , the hook member  306  may be included in and/or formed integrally with the part adapter  190 . The hook member  306  includes a rounded surface  308  and a sloped surface  310 . The rounded surface  308  engages the stop  292  of the support  78 ″. The sloped surface  310  engages the sloped surface  288  in the groove  286  of the support  78 ″. 
         [0089]    With additional reference to  FIGS. 17 through 19 , operation of the gripper  16 ″ will now be described in greater detail. In  FIG. 17 , the support  78 ″ of the gripper  16 ″ conforms to the implant  24  without using the part adapter system  180 . A clamp pad  80 ″ is actuated toward a clamp pad  82 ″ to clamp one of the protrusions  58  on the implant  24  with the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″. When one of the protrusions  58  on the implant  24  is clamped, the outer surfaces  142 ″,  284  of the support  78 ″ engage the inner surfaces  54  of the implant  24 . 
         [0090]      FIG. 17  shows a lateral distance L between the centerline of the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″ and those of the outer surfaces  284  on the support  78 ″ that are generally within a plane parallel to the centerline. This lateral distance L matches the lateral distance between the centerline of the protrusions  58  of the implant  24  and those of the inner surfaces  54  on the implant  24  that are generally within a plane parallel to the centerline. This enables the outer surfaces  284  of the support  78 ″ to engage the inner surfaces  54  of the implant  24 . 
         [0091]    In  FIG. 18 , the part adapter  190  enables the gripper  16 ″ to conform to an implant  24 ′. The clamp block  188  is actuated toward the part adapter  190  to clamp the part adapter  190  with the underside surface  266  of the clamp block  188 . The clamp pad  80 ″ is actuated toward the clamp pad  82 ″ to clamp one of protrusions  58 ′ on the implant  24 ′ with the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″. When one of the protrusions  58 ′ on the implant  24 ′ is clamped, the outer surfaces  302  of the part adapter  190  engage inner surfaces  54 ′ of the implant  24 ′. 
         [0092]      FIG. 18  shows a lateral distance L′ between the centerline of the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″ and those of the outer surfaces  302  on the part adapter  190  that are generally within a plane parallel to the surface centerline. This lateral distance L′ matches the lateral distance between the centerline of the protrusions  58 ′ on the implant  24 ′ and those of the inner surfaces  54 ′ on the implant  24 ′ that are generally within a plane parallel to the post centerline. The lateral distance on the implant  24 ′ is greater than the lateral distance on the implant  24 . The height of the projections  298 ,  300  on the part adapter  190  corresponds to this difference between the lateral distances on the implants  24 ,  24 ′. 
         [0093]    In  FIG. 19 , a part adapter  190 ′ enables the gripper  16 ″ to conform to an implant  24 ″. The clamp block  188  is actuated toward the part adapter  190 ′ to clamp the part adapter  190 ′ with the underside surface  266  of the clamp block  188 . The clamp pad  80 ″ is actuated toward the clamp pad  82 ″ to clamp one of protrusions  58 ″ on the implant  24 ″ with the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″. When one of the protrusions  58 ″ on the implant  24 ″ is clamped, outer surfaces  302 ′ of the part adapter  190 ′ engage the inner surfaces  54 ″ of the implant  24 ″. 
         [0094]      FIG. 19  shows a lateral distance L″ between the centerline of the clamp surfaces  84 ″,  86 ″ on the clamp pads  80 ″,  82 ″ and those of the outer surfaces  302 ′ on a part adapter  190 ′ that are generally within a plane parallel to the surface centerline. This lateral distance L″ matches the lateral distance between the centerline of the protrusions  58 ″ of the implant  24 ″ and those of the inner surfaces  54 ″ on the implant  24 ″ that are generally within a plane parallel to the post centerline. The lateral distance on the implant  24 ″ is greater than that on the implant  24 ′. Thus, the part adapters  190 ,  190 ′ are similarly configured except for the height of projections  298 ′,  300 ′, which is greater than that of the projections  298 ,  300 . 
         [0095]    Referring now to  FIG. 20 , an adapter nest  312  supports part adapters  190  through  190 ″″″. The adapter nest  312  includes a first clearance  314 , a second clearance  316 , a first wall  318  having a first groove  319 , and a second wall  320  having a second groove  321 . While only one of the grooves  319 ,  321  is shown, a set of the grooves  319 ,  321  is disposed at each of the locations in which one of the part adapters  190  through  190 ″″″ is shown. Each set of the grooves  319 ,  321  forms a universal slot accommodating any one of the part adapters  190  through  190 ″″″. 
         [0096]    The fit between the adapter nest  312  and each of the part adapters  190 ′ through  190 ″″″ is substantially similar such that only the fit between the adapter nest  312  and the part adapter  190  will now be discussed. The top surface of the first wall  318  of the adapter nest  312  engages the flat surface  294  of the part adapter  190 . The groove  319  in the first wall  318  engages the head of the fastener  304  fastening the hook member  306  to the part adapter  190 . The bottom surface of the groove  321  in the second wall  320  engages the flat surface  294  of the part adapter  190 . The two angled surfaces flanking the bottom surface of the groove  321  engage the two angled surfaces flanking the flat surface  294  of the part adapter  190 . 
         [0097]    Thus, the grooves  319 ,  321  in the walls  318 ,  320  of the adapter nest  312  cooperate to align the part adapter  190  in the adapter nest  312  using features on the part adapter  190 . The groove  319  uses the head on the fastener  304  to align the part adapter  190 . In this regard, the fastener  304  serves the dual purpose of fastening the hook member  306  to the part adapter  190  and aligning the part adapter  190  in the adapter nest  312 . The groove  321  uses the flat surface  294  and the angled surfaces flanking the flat surface  294  to align the part adapter  190 . 
         [0098]    Referring now to  FIG. 21 , operation of the gripper  16 ″ when taking the part adapter  190  from the adapter nest  312  will now be described. First, the gripper  16 ″ is positioned above the part adapter, as shown. Second, the gripper  16 ″ is lowered such that the stop  292  is adjacent to the rounded surface  308  on the hook member  306 . Third, the actuator  182  moves the clamp block  188  into engagement with the groove  208  in the part adapter  190 , as best shown in  FIG. 15 . Fourth, the gripper  16 ″ is raised to remove the part adapter  190  from the adapter nest  312 . 
         [0099]    Referring now to  FIG. 22 , a part adapter system  180 ′ is substantially similar to the part adapter system  180  such that only differences between the part adapter systems  180 ,  180 ′ will now be discussed. In the part adapter system  180 , the lever  184  abuts the pushrod  186 . In contrast, in the part adapter system  180 ′, a lever  184 ′ is coupled to a pushrod  186 ′. Thus, the lever  184 ′ pulls the pushrod  186 ′ when rotated in a direction away from the pushrod  186 ′. 
         [0100]    The part adapter system  180 ′ includes a clevis  322 , a fastener  324 , a fastener  326 , and a slot  328 . The clevis  322  is a u-shaped bracket sized to receive the lever  184 ′. A portion of the clevis  322  is not shown in order to show the fastener  326  and the slot  328 . The fastener  324 , which may be a set screw, fastens the clevis  322  to the pushrod  186 ′. The fastener  326 , which may be a pin, is inserted into holes (not shown) in the clevis  322  and into the slot  328  in the lever  184 ′ to couple the clevis  322  to the lever  184 ′. The slot  328  allows a second end  234 ′ of the lever  184  to move vertically as the lever  184 ′ rotates about a pivot  196 ′. 
         [0101]    Referring now to  FIG. 23 , an adapter nest  312 ′ is substantially similar to the adapter nest  312  such that only differences between the adapter nests  312 ,  312 ′ will now be discussed. When the gripper  16 ″ releases the part adapter  190 , gravity may be relied on to decouple the part adapter  190  from the gripper  16 ″. Alternatively, the part adapter  190  may include notches  330 , and brackets  332 , such as spring steel brackets, may be fastened to the adapter nest  312 ′ using fasteners  334 . The brackets  332  engage the notches  330  to retain the part adapter  190  on the adapter nest  312  as the gripper  16 ″ is moved away from the adapter nest  312 . This arrangement may be replaced with a ball detent (not shown) that functions similarly. 
         [0102]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention.