Abstract:
A pin clamp for clamping a workpiece includes a housing having a longitudinal axis and a locating pin extending through the housing. The locating pin is sized to be positioned within an opening of the workpiece. A finger is positioned adjacent to the locating pin and movable in a transverse direction relative to the longitudinal axis to retain the workpiece on the locating pin. An exterior driving linkage is configured to move the locating pin in opposite directions along the longitudinal axis. A locking arrangement is carried by the housing. A sequence cam is connected with the exterior driving linkage thereby allowing axial movement of the exterior driving linkage to be converted into transverse movement of the sequence cam. The sequence cam includes an engagement surface which engages the locking arrangement to lock the locating pin and the finger against the workpiece upon retraction of the exterior driving linkage.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation of U.S. patent application Ser. No. 13/653,803, entitled “PIN CLAMP WITH MULTI-THICKNESS CLAMPING FEATURE”, filed Oct. 17, 2012, which is a non-provisional of U.S. Provisional Application Ser. No. 61/548,448, entitled “PIN CLAMP WITH MULTI-THICKNESS CLAMPING FEATURE”, filed Oct. 18, 2011, which is incorporated herein by reference. This is further a non-provisional application based upon U.S. provisional patent application Ser. No. 62/149,319, filed Apr. 17, 2015, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to pin clamp assemblies. 
         [0004]    2. Description of the Related Art 
         [0005]    Pin clamps are typically used for gripping onto sheets of metal, often on automobile assembly lines so some process can be performed on that sheet metal. The pin clamp includes a locating pin that is extendable through a hole in the sheet metal. A finger extends from the locating pin which then retracts so the finger clamps down onto the sheet. Examples of pin clamps can be found in U.S. Pat. Nos. 7,182,326, 7,516,948, 7,448,607, 7,815,176, and 7,467,788. 
         [0006]    In today&#39;s automobile manufacturing environment, however, some automobiles may be manufactured in multiple configurations. For example, an automobile may be manufactured in a first configuration that employs an internal combustion engine. That same automobile may also be offered in a second configuration that employs a battery powered motor. In these instances, it might be necessary for that automobile to have a different frame depending on whether it is gas or electric powered. An electric powered automobile requires a stronger frame to hold the substantial weight of the batteries needed to power it. A different size frame may require a thicker metal. Because it is the same vehicle, however, it otherwise uses many of the same parts. This makes it desirable to use the same assembly line for both versions, if possible. 
         [0007]    Conventional pin clamps are adjusted to clamp down on workpieces of varied thicknesses. This is particularly the case for clamps having a hold mechanism that still clamp down on a workpiece even under power loss (such as pressurized air). These clamps need adjustment to accommodate this different thickness. Making such adjustments adds time and expense to the manufacturing process. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a pin clamp that can hold a car part of a first thickness, release the clamp from its power supply while it still holds onto the part, process the part, reattach the power supply to the clamp to release the part, and then start the process again but clamping onto another part having a second thickness. This allows the part to be processed anywhere along the assembly line without the clamp having to be constantly connected to a power source. It also no longer requires any readjustment of the pin clamp between removing the workpiece of first thickness and replacing it with a workpiece of second thickness. 
         [0009]    The pin clamp of the present invention includes an internal lock that compensates for, illustratively, up to about 1.0 millimeters of variation in material thickness. A lock holds the finger firm against the various material thicknesses. This means that panels of different thicknesses can be held by the clamp and all will be held firmly with no play. The pin clamp of the present invention further includes an exterior driving linkage that allows the pin clamp to be operated using an external mechanism. 
         [0010]    The invention in one form is directed to a pin clamp for clamping a workpiece. The pin clamp has a housing with a longitudinal axis and a locating pin extending through the housing. The locating pin is sized to be positioned within an opening of the workpiece. A finger is selectively radially extendable from and retractable into the locating pin in a transverse direction relative to the longitudinal axis to retain the workpiece on the locating pin. An exterior driving linkage is configured to move the locating pin in opposite directions along the longitudinal axis. A sequence bracket is attached to the housing. A lock bracket attached to the housing opposite the sequence bracket. A sequence cam is connected with the exterior driving linkage in a manner allowing axial movement of the exterior driving linkage to be converted into transverse movement of the sequence cam perpendicular to the longitudinal axis. The sequence cam includes a ledge configured to ride along a top surface of the sequence bracket during a first part of a clamping sequence. The sequence cam further includes an engagement surface which engages an angled surface of the lock bracket during a second part of the clamping sequence to lock the locating pin and the finger against the workpiece upon retraction of the exterior driving linkage. 
         [0011]    An advantage of the present invention is that it can be operated using an external mechanism while retaining the ability to remain clamped without constant application of input force. The pin clamp of the present invention is again capable of compensating for variations in work material thickness. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
           [0013]      FIG. 1  is a perspective view of an embodiment of a pin clamp of the present invention; 
           [0014]      FIG. 2  is an exploded perspective view of the pin clamp shown in  FIG. 1 ; 
           [0015]      FIG. 3  is another perspective view of the pin clamp shown in  FIGS. 1 and 2 , with part of the housing removed; 
           [0016]      FIGS. 4   a  and  4   b  are side and end views, respectively of the pin clamp shown in  FIGS. 1-3 ; 
           [0017]      FIG. 5-12  are side views illustrating a sequence of operation of the pin clamp of the present invention; 
           [0018]      FIGS. 13 and 14  are side views illustrating locking of the pin clamp of the present invention; 
           [0019]      FIG. 15  is an exploded perspective view of a cover, Z bracket and sequence cam; 
           [0020]      FIG. 16  is a top sectional view showing how the spring loaded Z bracket biases the sequence cam toward the lock bracket; 
           [0021]      FIGS. 17   a  and  17   b  are side and side sectional views, respectively, illustrating details of a linear actuator in the form of a piston and cylinder arrangement; 
           [0022]      FIG. 18  is a side view of an additional embodiment of the present invention; 
           [0023]      FIG. 19  is a side view of an additional embodiment of the present invention; 
           [0024]      FIG. 20  is a side view of an additional embodiment of the present invention; 
           [0025]      FIG. 21  is a side view of an additional embodiment of the present invention; 
           [0026]      FIG. 22  is an isometric cutaway view of an additional embodiment of the present invention; and 
           [0027]      FIG. 23  is an isometric cutaway view of an additional embodiment of the present invention. 
       
    
    
       [0028]    Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a pin clamp  2  which includes a housing  4  with a locating pin  6  extending therefrom. A collar  8  illustratively surrounds locating pin  6 . A finger  10  is selectively radially extendable from and retractable into the locating pin. A cover  12  attaches to housing  4  via fasteners  14 . This allows access to the internal components of clamp  2  as needed. A linear actuator in the form of a pneumatic actuator  16  extends from housing  4  illustratively opposite locating pin  6 . A portion of piston rod  122  partially extends from actuator  16  and includes a nut  124  illustratively attached to the end thereof. Fasteners  25  illustratively attach collar  8  to housing  4 . 
         [0030]    An exploded view of pin clamp  2  is shown in  FIG. 2 . This view depicts housing  4  with a cavity  18  formed therein to receive components of pin clamp  2  as further discussed. An opening  26  in housing  4  is configured to receive locating pin  6 . 
         [0031]    Illustratively, locating pin  6  is hollow so it may receive drive rod  28 . It also includes slots  30  and  32  along with an opening  34  configured to receive finger  10 . Collar  8  is shown with opening  36  configured to receive a portion of locating pin  6 . A ledge  38  may serve as a base surface for a workpiece in the form of a piece of sheet metal or other material that is intended to be clamped down by finger  10 . 
         [0032]    Fasteners  25  attach collar  8  to housing  4 . A cover plate  40  attaches to housing  4  via fasteners  42  in order to illustratively cover one side of cavity  18  opposite cover  12 . Rod  44  extends though locating pin  6  and supports cam roller  57  that travels along the internal cam surface of cam slot  74  as described further herein. A lock bracket  46  fits into cavity  18  using fastener  47 . Similarly, sequence bracket  48  fits into cavity  18  as well and attaches thereto via fastener  49 . A Z-bracket  50  with tabs  52  and  53 , and spring  51  are also located within housing  12  and is retained by plate  13 . A sequence cam  54 , a roller  56  and a post  58  are also directed inwardly of cavity  18 . Actuator  16  includes a piston rod  60  extending from one end and configured to couple to sequence cam  54  via rod  44  acting through cam roller  57 . In this illustrative embodiment, piston rod  60  is “U” shaped to accommodate sequence cam  54 . (See, also,  FIG. 17   b .) Rod  122  extends from the other end of actuator  16 . Fasteners  62  attach actuator  16  to housing  4 . 
         [0033]    In the illustrated embodiment, cam roller  57  defines a cam follower that is positioned within and engages the internal cam surface of slot  74 . However, it is possible to use a different type of cam follower. For example, rod  44  could itself define a cam follower which rides within the cam surface of slot  74 . 
         [0034]    As previously discussed, pin clamp  2  is configured to first, clamp onto a material of first thickness under fluid power (such as pressurized air), then have that power disconnected, still securely hold the material as it moves down the assembly line, and then reattach fluid power to release the material. Then, that same pin clamp, without any further adjustment or modification, is able to clamp down onto a material of a second thickness under subsequent fluid power and repeat the process again. In other words, the pin clamp may hold pieces of sheet metal or other workpieces of a variety of thicknesses and hold those workpieces under power loss without any modification to the pin clamp. 
         [0035]    In alternative embodiments the power may be electrical or hydraulic. 
         [0036]    A perspective isolated view of several of the internal components of pin clamp  2  is shown in  FIG. 3 . This view depicts the relative positioning of several of the components that help keep the pin clamp locked down onto a workpiece of particular thickness when no fluid pressure is being applied to finger  10 . As shown herein, cover  12  includes a spring bracket  64  configured to hold Z-bracket  50  and a spring  51 . Tab  52  is configured to push sequence cam  54 . Sequence cam  54  extends through slot  32  through locating pin  6 . Rod  44  and dowel  70  are disposed through slot  30 . Located on opposite sides of locating pin  6  is lock bracket  46  and sequence bracket  48 . Ledge  66  of sequence cam  54  rides along the illustrative top surface of sequence bracket  48  while roller  56  is configured to engage angled surface  68  of lock bracket  46 . Roller  56  defines an engagement surface which locks with angled surface  68 . Angled surface  68  is positioned at an angle of between 0° to 10°, relative to a direction of movement of sequence cam  54 , and may be a flat surface or have a curved or differently shaped surface. 
         [0037]      FIG. 3  also shows how piston rod  60  extends up through locating pin  6 . The U-shaped channel in piston rod  60  is illustratively configured to allow sequence cam  54  to pass in between without interference. Drive rod dowel  70  also extends through slot  30  and is disposed in cam slot  72  of sequence cam  54 . It will be appreciated as further discussed herein that dowel  70  also connects sequence cam  54  with drive rod  28  so that the path of cam slot  72  dictates the corresponding movement of drive rod  28  which in turn dictates the extension or retraction of finger  10 . Rod  44  connects piston rod  60  with sequence cam  54  via slot  74  for moving the same in directions  76  and  78 . (See, also,  FIG. 4 .) 
         [0038]    Progression views depicting how pin clamp  2  operates to clamp down and lock onto a workpiece is shown in progression views of  FIGS. 4-7 . As shown in  FIG. 4   a , locating pin  6  is illustratively positioned a distance  80  above collar  8 . In this illustrative embodiment, distance  80  may be 12.5 millimeters, for example. It is appreciated, however, that this distance is illustrative and such distance can be modified as desired. At this point, ledge  66  of sequence cam  54  is sitting on top of lock bracket  48 . It is contemplated that movement of piston rod  60  from actuator  16  in direction  82  will begin moving sequence cam  54  in direction  78 . As shown in  FIG. 4   b , the upper position of slot  74  includes a locking position  86  that prevents roller  57  from moving if there is an air pressure loss. Also included is detent  59  which helps prevent piston rod  60  from dropping out of locking position  86  under a loss of fluid power. Illustratively, sequence cam  54  receives a bias force in direction  78  from bracket  50 . This keeps detent  59  pushing against roller  57  regardless of whether air pressure is being applied to piston rod  60 . If air pressure is lost, detent  59  of sequence cam  54  is still pushing against roller  57  preventing it from dislodging from locking position  86 . 
         [0039]    The view in  FIG. 5  depicts the consequence of piston rod  60  moving downward in direction  82 . As this happens, roller  57  pulls down out of the pin extended position  86 . The roller  57  then contacts surface  75  in cam slot  74 , which causes cam  54  to slide in direction  78 . This motion causes drive rod  28  to move downwards. Cam follower  92  on drive rod  28  also moves in direction  82 . Cam follower  92  is engaged in cam slot  94 , which pushes finger  10  in direction  76 , extending finger  10  outward from locating pin  6 . As sequence cam  54  slides in direction  78 , finger  10  moves to a fully extended position, just as ledge  66  of sequence cam  54  is no longer engaged by sequence bracket  48 . Roller  56  is mounted on a pin  55  that is connected to sequence cam  54 , and moves from cavity  90  while approaching lock bracket  46 . It is appreciated that the configuration and size of cam slot  94  can be modified to create the desired movement of finger  10  upon response to the drive rod&#39;s movement. 
         [0040]    The view of clamp  2  in  FIG. 6  shows locating pin  6  moving towards its clamped and locking position. As piston rod  60  moves in direction  82 , roller  57  contacts cam surface  98  that is part of cam  74 . The resulting force causes locating pin  6  to move in direction  82 , thus narrowing the gap between collar  8  and finger  10 . At least a portion of roller  56  is lower than lock bracket  46 . 
         [0041]    The view in  FIG. 7   a  shows locating pin  6  of clamp  2  moved to its final clamping thickness represented by spacing  100 . Illustratively, the spacing maybe 2.5 mm. At this point, a workpiece will be securely held by finger  10  against collar  8 . As piston rod  60  moves downward in direction  82 , roller  57  moves down angled surface  98  of cam slot  74 . This increasing angle forces sequence cam  54  to continue moving in direction  78  and begin wedging roller  56  up against angled surface  68  creating a locking function. Cam slot  72  is shaped so that as sequence cam  54  continues to move in direction  78 , the drive rod  28  remains stationary with respect to locating pin  6 , so that the cam follower  92  on drive rod  28  does not move within cam slot  94  and so that finger  10  does not withdraw. At this point, a loss of air pressure to piston rod  60  will not cause finger  10  to release itself from the workpiece. A practical effect of this is that while clamp  2  holds onto the workpiece, its power source may be disconnected allowing clamp  2  and its workpiece to move to a different location. Despite this, clamp  2  still holds the workpiece in place while maintaining the clamping force originally provided by pneumatic actuator  16 . 
         [0042]      FIGS. 8 and 9  demonstrate the operation of pin clamp  2  to remove the workpiece. It should be appreciate, however, that in the illustrative embodiment, prior to the movement shown in  FIGS. 8 and 9 , no power is being supplied to clamp  2 . Pressurized air is not needed to maintain the clamping force until the workpiece is needed to be removed from clamp  2 . 
         [0043]    As shown in  FIGS. 7 ,  8 , and  9 , roller  57  moves within cam slot  74  of sequence cam  54 . Cam slot  74  is shaped as such to generate low power when piston rod  60  is moving in direction  82  toward the clamped position, and high power when moving in direction  84  toward the release position. This may be made necessary by loads introduced due to welds or by weld guns, requiring increased force in the releasing direction. When clamping, roller  57  rides along surface  98  which produces a low force. Roller  56  moving along the illustrative 7 degree angle of surface  68  generates enough additional downward force to allow the necessary structures to move. Conversely, when raising piston rod  60  in direction  84 , roller  57  travels along surface  102  which creates a high force to move sequence cam  54  back in direction  76  and help remove roller  56  from under surface  68 . 
         [0044]    To remove the workpiece, pressurized air is resupplied to clamp  2  moving piston rod  60  in direction  84 . This moves roller  57  upwards in direction  84  as well and against cam surface  102  of cam slot  74 . This curved shape of surface  102  causes sequence cam  54  to move in the opposite direction  76 . This movement of sequence cam  54  begins to extricate roller  57  from surface  68  of lock bracket  46 . 
         [0045]    The view in  FIG. 9  further demonstrates the operation of clamp  2  as piston rod  60  moves in direction  84 . As shown, roller  57  continues following surface  102  of slot  74  which continues to move sequence cam  54  in direction  76 . Roller  56  clears surface  68  of locking bracket  46  further allowing sequence cam  54  and locating pin  6  to move in direction  84 . This movement also begins to move pin  70  in slot  72  which will (though not yet) move follower  92  in slot  94  to retract finger  10 . As shown in this view, however, at this point locating pin  6  is what is being moved by piston rod  60  to raise finger  10  from the workpiece a distance indicated by reference number  104 . Continued movement of piston rod  60  in direction  84 , moves pin  70  into angled section  88  pushing piston rod  28  upward in direction  84  relative to the locating pin  6 . This retracts finger  10  and moves roller  57  up into locking section  86 . In other words, clamp  2 , as shown in  FIG. 9 , continues to move as described until the components are in the position as shown in  FIG. 4  where the process may start all over again. 
         [0046]    To that end, the view in  FIG. 10  depicts clamp  2  clamping down on a workpiece that is thinner than the workpiece clamped down onto in  FIGS. 4-7 . In this illustrative embodiment, spacing  106  may illustratively be 2 rams instead of 2.5 millimeters, as employed in  FIGS. 4-7 . In  FIG. 10 , the sequence of movement is essentially the same as that described in  FIGS. 4-7 , except now the further clamping distance (for a thinner workpiece) means sequence cam  54  will move even further in direction  78  which makes roller  56  wedge further along surface  68  of lock bracket  46 . No other components to clamp  2  need to be manually adjusted to accommodate a thinner workpiece. As shown, locating pin  6  is drawn further down by piston rod  60  in direction  82  moving sequence cam  54  in direction  78  in similar fashion as that described in  FIGS. 4-7 . The only difference is that the spacing  106  is smaller than spacing  100  in  FIG. 7 . This moves roller  57  further down cam surface  98  which allows pin  70  to move further along slot  72  and roller  56  further down surface  68  in direction  78 . Compare the relative positioning of rollers  56  and surface  68  between  FIGS. 7 and 10 . This means that when pressurized air is disconnected from clamp  2 , finger  10  and locating pin  6  will still hold the thinner workpiece in the same manner as that shown in  FIG. 7  for a thicker workpiece. The views in  FIGS. 11 and 12  are similar to that of  10  except pin clamp  2  is now clamping onto even thinner workpieces, such as for the spacing shown in  108  of  FIG. 11 and 110  of  FIG. 12 . It is appreciated that spacing  110  is thinner than spacing  108  which is itself thinner than spacing  106 . To accomplish this, sequence cam  54  is simply moved further in direction  78  in both instances to accommodate for these thinner workpieces. Comparing  FIGS. 10 ,  11 , and  12 , it is easy to see how clamping down on a thin workpiece simply means roller  56  is moved further along surface  68  in direction  78 . 
         [0047]    An issue that may occur is slight movement of locating pin  6  while clamped down onto a workpiece. If clamp  2  is locked and air pressure is removed, if an upward force was exerted on pin  6  it could possibly move that pin slightly despite staying locked. A repetitive upward force acting on pin  6  may result in multiple movements of the same which could knock the clamp out of tolerance. For example, if a 500 pound upward force was applied to locating pin  6 , it could possibly move despite roller  56  being wedged against surface  68 . A welding gun may exert this amount of force or even more onto a pin clamp. It is believed this movement occurs because the components in the clamp stretch just a little bit. Under a 500 pound force, the movement may be only 0.001 inch. But a repetitive force acting on locating pin  6  could multiply that 0.001 distance many times. Under these conditions roller  56  moves a small amount but does not roll back into its original clamp position which may cause a creeping effect which may loosen the clamp&#39;s grip on the workpiece. To address this issue, Z-bracket  50  with spring  51  are configured to act on sequence cam  54  to push roller  56  back into position each time it is inadvertently moved. As shown in  FIG. 13 , when a force  112  acts upward opposite the clamping direction, roller  56  moves with respect to surface  68 . Tab  52  acts on sequence cam  54  biasing it in direction  78  to push roller  57  back to its original position, as shown in  FIG. 14 . 
         [0048]    An exploded view of these components is shown in  FIG. 15 . Tab  52  of bracket  50  is configured to engage edge  114  of sequence cam  54 . (See also  FIG. 5 .) As spring  51  acts on tab  53 , it acts to keep a bias on tab  52  against sequence cam  54 . A spring bracket  64  is fitted on cover  12  to receive bracket  50  and spring  51 . Illustratively, bracket  64  includes a spring cavity  116  and slot  118  holds spring  51  and bracket  50 , respectively. 
         [0049]    A top cross-sectional view of clamp  2  is shown in  FIG. 16 . This view shows the relative positioning of bracket  50 , spring  51  and sequence cam  54 . As shown, spring  51  biases tab  53  which causes tab  52  to act on sequence cam  54  biasing the same towards lock bracket  46 . This helps keep roller  56  properly under lock bracket  46 . 
         [0050]    Front elevational and side cross-sectional views of clamp  2  are shown in  FIGS. 17   a  and  b . These views, and particularly the cross-sectional view, demonstrate how piston rod  60  is attached to a piston  120  inside actuator  16 . Another portion of piston rod  122  extends from piston  120  partially exterior of actuator  16  and includes a nut  124  attached to the end thereof. Illustratively, nut  124  may be a target for a proximity switch to detect when the clamp is closed. The surface of  124  may be reflective so that when a beam of light hits it when in a certain location, the switch knows the clamp has achieved a certain condition (such as closed). The upper portion of piston rod  60  is coupled to sequence cam  54  via rod  44 . In this illustrative embodiment, roller  57  is shown within cam slot  74 . Illustratively, additional rollers  126  also support rod  44 . Roller  57  is configured to transmit force while rollers  126  carry side load forces generated by cam slot  74 . This has the affect of keeping the piston rod  60  centered. 
         [0051]      FIGS. 18 through 21  show additional views of embodiments of the present invention, a pin clamp  2  having a housing  4  and a locating pin  6  having a finger  10 . The locating pin  6  again extends through collar  8  attached to housing  4  using fasteners  25 . A cover  12  is again removably attached to housing  4  using fasteners  14  (not shown), thereby allowing access to the internal components of clamp  2  as needed. On the opposite side of housing  4 , a cover plate  40  is again removably attached to housing  4  using fasteners  42 , also allowing access to the internal components of clamp  2  as needed. The pin clamp  2  in  FIGS. 18 through 21  is again actuated using pneumatic actuator  16  having a piston rod  122  and nut  124 . Pin clamp mounting holes  128  are provided for mounting the pin clamp  2  to a given support structure (not shown). 
         [0052]    Turning now to  FIGS. 22 and 23 , isometric cutaway views show an additional embodiment of the present invention compared with a previous embodiment of the present invention. In particular,  FIG. 22  shows a pin clamp  2  having a housing  4  and a locating pin  6  with a finger  10  being actuated using a pneumatic actuator  16 , whereas  FIG. 23  shows a pin clamp  2  again having a housing  4  and a locating pin  6  with a finger  10  but being actuated using an exterior driving linkage  150  that slides back and forth in directions  82  and  84  using a bearing plate  152 . Both embodiments are again provided with a cavity  18  within the housing  4 , in which the sequence cam  54  interacts with the locating pin  6  and finger  10  through the cam slot  72 , drive rod dowel  70 , and drive rod  28  in the same manner as previous embodiments. A Z-bracket  50  again interacts with the housing  4 , cover  12  retained by fasteners  14 , and sequence cam  54  to bias sequence cam  54  in direction  78 . Collar  8  retained by fasteners  25  again guides locating pin  6 . 
         [0053]    The exterior driving linkage  150  shown in  FIG. 23  takes the place of the piston rod  60  and rod  44  shown in  FIG. 22 , so that in  FIG. 23  dowel pin  154  passes through bearing plate  152  and interacts with the cam slot  74  of the sequence cam  54  through the cam roller  57  in the same way that piston rod  60 , rod  44 , and cam roller  57  interact with the cam slot  74  in previous embodiments. In this way, force applied to boss  170  of bearing plate in directions  82  and  84  operates the locating pin  6  and finger  10  of the pin clamp  2  shown in  FIG. 23  in the same way that force applied to piston rod  60  in directions  82  and  84  by piston rod  122  connected to piston  120  of pneumatic actuator  16  operates the locating pin  6  and finger  10  of the pin clamp  2  in  FIG. 22 . In place of cover plate  40  and fasteners  42 , the pin clamp  2  in  FIG. 23  is provided with a cover plate  156  having a slot  158  and retained by fasteners  160 . Boss  170  extends through slot  158  of cover plate  156 , thereby providing a point for exterior driving linkage  50  to be connected to and driven by an external mechanism (not shown) such as a linkage or actuator. 
         [0054]    In place of the pin clamp mounting holes  128  in the housing  4  of pin clamp  2  shown in  FIG. 22 , the pin clamp  2  shown in  FIG. 23  is provided with a mounting assembly  164  that is attached to the housing  4  using retaining fasteners  166 . The mounting assembly  164  is provided with a mounting bore  168  by which it may be attached to an external structure (not shown). An end cover  162  separates the mounting assembly  164  from the internal mechanism of the pin clamp  2  and protects the internal mechanism from contamination. 
         [0055]    While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.