Patent Publication Number: US-6902160-B1

Title: Locating pin with integrated clamp

Description:
RELATED APPLICATION 
   This application claims priority to Ser. No. 60/441,771 filed Jan. 22, 2003, which is entitled “Locating Pin with Integrated Clamp”, and Ser. No. 60/448,054 filed Feb. 17, 2003, which is entitled “Locking Mechanism for an End Effector”, which are incorporated herein by reference in their entirety. 

   TECHNICAL FIELD OF INVENTION 
   The present invention relates to a fixture for locating and clamping a workpiece. More specifically, the present invention relates to a floating clamping arm which is easily removable from the fixture. 
   BACKGROUND OF THE INVENTION 
   Automated pneumatic clamping devices are commonly utilized in manufacturing environments to secure a workpiece, such as a sheet metal part, to a base for processing, such as welding, punching, or assembly with other parts. Generally, conventional clamping devices comprise a piston and cylinder, wherein the piston is operable to translate within the cylinder in order to force a clamping member to rotate about an axis.  FIG. 1  illustrates an exemplary prior art clamping mechanism  10  comprising a clamping member  12  which is rotatably coupled to a housing  14  via a fixed pivot pin  16 . The clamping mechanism  10  is operable to generally clamp a flat part  18  between an end  20  of the clamping member  12  and the housing  14  by the application of air pressure to a cylinder  22 . The application of air pressure to the cylinder  22  generally causes a piston  24  to translate therein, wherein a drive pin  26  associated therewith is operable to generally rotate the clamping member  12  about a single axis  28  associated with the fixed pivot pin  16 . 
   Typically, the clamping member  12  is considered a wearable part, wherein the clamping member is replaced regularly. The clamping member  12  of the prior art, however, has typically been fairly difficult to remove from the housing  14 , because a removal of several other components associated with the clamping member is typically required prior to the removal of the clamping member. Conventionally, the fixed pivot pin  16  is generally fixed to the housing  14  and the clamping member  12  is generally coupled to the pivot pin  16  via a hole  30  in the clamping member. Such a pin and hole arrangement, therefore, typically requires the pivot pin  16  to be removed from the housing  14  in order to remove and replace the clamping member  12 . Furthermore, other components such as a location pin  32 , and/or other components are also typically removed prior to the removal of the clamping member  12  from the housing  14 . Removal of such components can increase maintenance time and cost associated with the prior art clamping mechanism  10 . 
   Furthermore, many applications exist wherein the workpiece  18  comprises an upward-facing flange  34 , and wherein a locking arm  36  associated with the clamping member  12  must clear the flange, yet still provide an adequate clamping force to the workpiece. The presence of the flange  34  can cause difficulties when dealing with conventional clamping mechanisms, since the conventional clamping mechanisms are generally limited to the fixed axis  28  of rotation of the clamping member  12 . 
   Still further, typical pneumatic clamping devices of the prior art operate via a gas pressure (e.g., 60 PSI or greater) being applied to a first portion  38  or a second portion  40  of the cylinder  22  via a respective first port  42  or second port  44  which is in fluid communication with the cylinder. The piston  24  is generally forced by the gas pressure between a first position  46  and a second position  48  within the cylinder  22 , depending on which of the first port  42  or the second port  44  is pressurized. Gas which resides in the second portion  38  of the cylinder  22 , for example, is generally exhausted to atmosphere via the second port  44  upon an application of the gas pressure to the first port  42 , thus causing the piston  24  to translate from the first position  46  to the second position  48 . In general, a velocity of the piston  24  translating within the cylinder  22  rapidly accelerates upon the application of gas pressure to either of the first port  42  or the second port  44 , and rapidly decelerates once the piston has reached an end  50  of the cylinder. 
   The travel seen by the piston  24  between the ends  50  of the cylinder  22  generally defines a stroke S of the piston. Typically, the rapid deceleration at the end of the stroke S of the piston  24  can produce unwanted impact forces, both to components of the pneumatic device  10  such as the piston  24 , cylinder  22 , drive pin  26 , and clamping member  12 , as well as undesirable forces exerted on the workpiece  18 , wherein undesirable effects such as deformations or dimples may result in the workpiece. Conventional attempts to minimize the impact forces at the ends of the stroke S have included, for example, cushioning devices, such as a “snubber”. A typical snubber  52  illustrated in  FIG. 1  comprises an additional self-contained snubber piston  54  and snubber cylinder  56 , wherein a translational velocity of the snubber piston is generally limited by a gas or spring  58  residing within the snubber cylinder. Typically, the snubber  52  is arranged within the pneumatic device  10  such that the piston  24  of the pneumatic device contacts the snubber piston  56  near the end  50  of the stroke S of the pneumatic device, wherein the translation of the snubber piston generally slows the translation of the pneumatic device piston. Conventional cushioning devices for limiting impact forces, however, are generally prone to wear, and furthermore add complexity to the pneumatic device. 
   Therefore, a need exists for a clamping fixture which provides for easy removal of the clamping member from the fixture, as well as a need for a simple apparatus for minimizing impact forces seen in pneumatic devices. 
   SUMMARY OF THE INVENTION 
   The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is intended to neither identify key or critical elements of the invention nor delineate the scope of the invention. Its purpose is to present some concepts of the invention in a simplified form as a prelude to the more detailed description that is presented later. 
   The present invention is directed toward a device for locating and clamping a workpiece. According to one exemplary aspect of the present invention, a locating and clamping fixture is disclosed, wherein the locating and clamping fixture comprises a generally hollow body and a floating clamping arm, wherein the floating clamping arm is generally easily removable from the hollow body. The fixture, for example, further comprises a first cam follower located within the hollow body and a drive pin operable to translate along a first axis associated therewith. The drive pin further comprises a second cam follower, wherein the second cam follower is further operable to translate along the first axis in conjunction with the translation of the drive pin. 
   The floating clamping arm disclosed in the present invention comprises a first cam surface, a second cam surface, and a gripping portion, wherein the first cam surface and the second cam surface, for example, are operable to respectively engage the first cam follower and the second cam follower. The first cam surface and the second cam surface, for example, are generally open-looped in configuration, wherein the first cam follower and the second cam follower are operable to be disengaged from the first cam surface and the second cam surface, respectively. 
   The drive pin is further operable to provide a driving force to the clamping arm, wherein upon an application of the driving force to the clamping arm, the clamping arm is operable to rotate and linearly translate with respect to the body. The gripping portion of the clamping arm, for example, is further operable to extend over the workpiece, wherein the gripping portion is operable to generally clamp the workpiece to the body. 
   According to another exemplary aspect of the present invention, the locating and clamping fixture further comprises a locating pin, wherein the locating pin is operable to generally locate the workpiece with respect to the hollow body. The locating pin, for example, is generally hollow, and comprises an aperture therethrough, wherein the gripping portion of the floating clamping arm is operable to selectively translate through the aperture upon the application of the driving force. 
   In accordance with yet another exemplary aspect of the present invention, an anti-rotation mechanism is provided, wherein the anti-rotation mechanism generally limits a rotation of the drive pin with respect to the hollow body. According to another exemplary aspect of the present invention, a piston and cylinder are associated with the hollow body, wherein the piston is operably coupled to the drive pin, and wherein an application of compressed gas within the cylinder is operable to translate the piston with respect to the cylinder, thereby providing the driving force. 
   According to still another exemplary aspect of the present invention, the locating and clamping fixture comprises a locking mechanism, wherein upon a loss of the driving force, the locking mechanism is operable to generally maintain a position of the floating clamping arm with respect to the body. The drive pin, for example, comprises a driver portion and a driven portion, wherein the driver portion and the driven portion are operable coupled to one another. The locking mechanism, for example, comprises one or more rollers associated with the body, the driver portion and the driven portion of the drive pin, wherein the one or more rollers are generally operable to selectively translate within the body, as well as to selectively limit a translation of the clamping arm, depending on a position of the drive pin. 
   Furthermore, in accordance with another exemplary aspect of the present invention, a cushioning mechanism is disclosed, wherein the cushioning mechanism is operable to limit an impact force associated with a piston within a cylinder. For example, the cushioning mechanism comprises one or more cushioning pins associated with the piston, and one or more respective cushioning holes associated with the cylinder. The one or more cushioning holes, in conjunction with the one or more respective cushioning pins, for example, are operable to generally selectively limit a fluid communication between an interior portion of the cylinder with one or more respective ports associated with the cylinder. The one or more cushioning pins, for example, are operable to translate into and out of the one or more cushioning holes, wherein a flow of compressed gas between the interior portion of the cylinder and the one or more ports is generally limited by the cushioning pins, depending on the location of the piston with respect to the cylinder. 
   To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a cross-sectional view of an exemplary prior art pneumatic device. 
       FIG. 2  illustrates a cross-sectional view of a locating and clamping fixture in a locating position according to one exemplary aspect of the present invention. 
       FIG. 3  illustrates a plan view of an clamping arm according to another exemplary aspect of the present invention. 
       FIG. 4  illustrates a cross-sectional view of a locating and clamping fixture in a clamping position according to yet another exemplary aspect of the present invention. 
       FIGS. 5A–5F  illustrate a locating and clamping fixture in various positions between and including the locating position of  FIG. 2  and the clamping position of  FIG. 4  according to still another exemplary aspect of the present invention. 
       FIGS. 6A–6E  illustrates a removal of a floating clamping arm from a locating and clamping fixture according to another aspect of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention will be described with reference to the drawings wherein like reference numerals are used to refer to like elements throughout. It should be understood that the description of these aspects are merely illustrative and that they should not be taken in a limiting sense. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be evident to one skilled in the art, however, that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate description of the present invention. 
   The present invention is directed towards a fixture for positionally locating and clamping a workpiece to a surface. The fixture, for example, comprises a clamping arm operable to clamp the workpiece to the surface, wherein the clamping arm is easily removable from the fixture. Furthermore, the present invention is directed towards a cushioning apparatus, wherein the cushioning apparatus may be utilized in the locating and clamping fixture, and wherein the cushioning apparatus generally reduces a velocity of a piston translating within a cylinder associated with the fixture. 
   Referring now to the figures,  FIG. 2  illustrates an exemplary locating and clamping fixture  100  according to one aspect of the present invention, wherein the locating and clamping fixture is operable to generally locate and clamp a workpiece  105  in a predetermined position. The fixture  100 , for example, comprises a generally hollow body  110  and a clamping arm  115 , wherein at least a portion  116  of the clamping arm is operable to rotate and translate within the body. A locating pin  120  is associated with the body, wherein the locating pin is operable to generally locate the workpiece  105  to a predetermined position when the workpiece is placed on the fixture  100 . The locating pin  120 , for example, is generally cylindrical and extends in an elongate manner outwardly from the body  110 . The locating pin may still further be removably mounted to the body via one or more screws (not shown). The locating pin  120  is operable to generally locate the workpiece  105  with respect to the body  110 , wherein the workpiece, for example, comprises a hole  106  therethrough, and wherein a placement of the workpiece onto the fixture  100  generally comprises placing the hole over the locating pin, therein passing the locating pin through the hole. The locating pin  120  may further comprise a tapered end  121 , wherein the tapered end is operable to generally guide the workpiece  105  onto the locating pin. 
   According to another exemplary aspect of the invention, the locating pin  120  comprises a generally hollow portion  122  and an aperture  123  therethrough, wherein at least another portion  124  of the clamping arm  115  is operable to generally reside within the hollow portion. Alternatively, the locating pin  120  may comprise one or more guide members (not shown), wherein the one or more guide members are operable to generally locate the workpiece  105  with respect to the fixture  100 . 
   In accordance with another aspect of the present invention, the locating pin  120  is operable to generally maintain a horizontal spatial position of the workpiece  105  with respect to the fixture  100 . According to one exemplary aspect of the invention, the workpiece  105 , may comprise a flange  107  associated with the hole  106 , wherein the flange extends outwardly from a surface  108  of the workpiece by a predetermined amount (e.g., a flange extending about 2–3 mm vertically from the surface of the workpiece) around a diameter of the hole. Such flanges  107 , for example, are commonly found in workpieces  105  such as automotive components, wherein the flange generally provides rigidity and/or additional structural integrity to the workpiece. 
   According to another exemplary aspect of the present invention, the clamping arm  115  is operable to secure the workpiece  105  relative to the fixture  100 . The clamping arm  115 , for example, comprises a gripping portion  125  at a distal end  128  thereof, wherein the clamping arm is operable to generally maintain a vertical spatial position of the workpiece  105  with respect to the fixture  100 . The clamping arm  115  is generally operable to clamp the workpiece  105  between the gripping portion  125  and a base portion  129  of the fixture, wherein the base portion is associated with the one or more of the body  110  and the locating pin  120 . According to one example, the base portion  129  is integral to the locating pin  120 . According to another example, the base portion  129  is integral to the body  110 . The gripping portion  125  of the clamping arm  115 , for example, is generally U-shaped, wherein an end surface  130  of the gripping portion is operable to engage the surface  108  of the workpiece  105 , and wherein the generally U-shaped gripping portion is operable to generally straddle the flange  107 , thereby limiting contact between the clamping arm and the flange. 
   According to yet another example, the gripping portion  125  of the clamping arm  115  is operable to translate through the aperture  123  in the locating pin  120 . The fixture  100  of  FIG. 2  is illustrated in a locating position  131  (unclamped position), wherein the workpiece  105  can be generally located to and/or removed from the locating pin  120 . While in the locating position  131 , the gripping portion  125  of the clamping arm  115  generally resides within the hollow portion  122  of the locating pin  120 , wherein the workpiece  105  can be placed over the locating pin without interference with the clamping arm. 
   According to another exemplary aspect of the present invention, the fixture  100  further comprises a drive pin  135 , wherein the clamping arm  115  is generally coupled to the drive pin. The drive pin  135  is operably to linearly translate within the body  110  along a first axis  136 , wherein the translation of the drive pin is associated with a predetermined movement of the clamping arm  115 , as will be discussed infra. The drive pin  135 , for example, is further operably coupled to a piston  140 , wherein the piston is operable to linearly translate along the first axis  136  within a cylinder  145 . According to one example, the cylinder  145  is separately mounted to the body  110 , wherein the cylinder can be separated from the body by a removal of one or more fasteners (not shown). Alternatively, the cylinder  145  may be integral to the body  110  of the fixture  100 , wherein a bore (not shown) within the body generally defines the cylinder. 
   The translation of the piston  140  within the cylinder  145 , for example, is operable to provide a driving force F to the drive pin  135 , wherein the driving force is operable to cause the drive pin to linearly translate along the first axis  136  within the body  110 . As an alternative, the piston  140  and cylinder  145  may be replaced by a servo motor (not shown) or other electromechanical, pneumatic, or hydraulic mechanism which is operable to provide the driving force F to the drive pin  135 . Accordingly, any mechanism operable to provide the driving force F to the drive pin  135  is contemplated as falling within the scope of the present invention. 
   According to another exemplary aspect of the invention, the fixture  100  further comprises a first cam follower  150  and a second cam follower  155 , wherein the first cam follower is associated with the body  110 , and wherein the second cam follower is associated with the drive pin  135 . One or more of the first cam follower  150  and second cam follower  155 , for example, may comprise a cylindrical pin or a roller bearing, wherein the first cam follower and the second cam follower are substantially resistant to frictional wear. The first cam follower  150 , for example, is generally fixed with respect to the body  110 , while the second cam follower  155  is generally fixed with respect to the drive pin  135 . The second cam follower  155  is furthermore moveable with respect to the body  110  along the first axis  136  in conjunction with the translation of the drive pin  135 . Still further, the drive pin  135 , and hence the second cam follower  155 , are moveable between an extended position  156  (e.g., as illustrated in  FIG. 2 ) and a retracted position  157  (e.g., as illustrated in  FIG. 4 ) along the first axis  136 . 
   In accordance with yet another exemplary aspect of the present invention, the clamping arm  115  comprises a floating clamping arm  160 , wherein the floating clamping arm is operable to be easily removed from the fixture  100 . The floating clamping arm  160 , for example, comprises a first cam surface  165  and a second cam surface  170 , wherein the first cam follower  150  is operable to engage the first cam surface, and wherein the second cam follower  155  is operable to engage the second cam surface. The first cam surface  165  and the second cam surface  170 , for example, are arranged such that upon the translational movement of the drive pin  135  (and hence, the translational movement of the second cam follower  155  with respect to the body  110 ), the floating clamping arm  160  is operable to linearly translate and rotate with respect to the body  110 . The floating clamping arm  160  is, therefore, positionable within the body  110  via the translation of the drive pin  135  between the extended position  156  of  FIG. 2  and the retracted position of  FIG. 4 . For example, the floating clamping arm  160  is operable to translate between an unclamped position (e.g., locating position  131  as illustrated in  FIG. 2 ) when the drive pin  135  is in the extended position  156 , and a clamped position  171  (e.g., as illustrated in  FIG. 4 ) when the drive pin is in the retracted position  157 . 
   The clamping arm  160 , for example, is not rigidly fixed to either of the first cam follower  150  or the second cam follower  155 , wherein the first cam surface  165  and the second cam surface  170  are operable to both linearly translate and to rotate with respect to each of the first cam follower and the second cam follower. Therefore, floating clamping arm  160 , for example, may be manually maneuvered between the first cam follower  150  and the second cam follower  155  in the absence of the driving force F. Furthermore, the floating clamping arm  160  can be easily removed from the body  110 , as will be described infra. 
     FIG. 3  illustrates the exemplary floating clamping arm  160 , wherein the floating clamping arm comprises the first cam surface  165 , the second cam surface  170 , and the gripping portion  125 . One or more of the first cam surface  165  and the second cam surface  170 , for example, are curvilinear in shape, wherein a configuration of the first cam surface and the second cam surface generally defines the predetermined movement of the floating clamping arm  160  with respect to the body  110  of  FIG. 2 . According to yet another exemplary aspect of the present invention, the first cam surface  165  and the second cam surface  170  have a generally open looped configuration, wherein the respective first cam follower  150  and second cam follower  155  are operable to engage and disengage the respective first cam surface and second cam surface by the rotation and translation of the floating clamping arm  160 . Such an open looped configuration is advantageous over conventional clamping arms in that the floating clamping arm  160  of the present invention can be removed from the body  110  without a removal of the first cam follower  150  or the second cam follower  155  from the body. 
   Referring again to  FIG. 3 , the first cam surface  165 , for example, comprises a first portion  172  which is generally parallel to the first axis  136  and a second portion  174  which is offset at a first angle from the first axis when the clamping arm  160  is viewed in the locating position  131 , as illustrated in  FIG. 2 . Furthermore, the second cam surface  170  comprises a third portion  176  which is generally parallel to the first axis  136  and a fourth portion  178  which is offset at a second angle from the first axis when the floating clamping arm  160  is viewed in the retracted position illustrated in  FIG. 2 . According to one example, the first angle is offset from the first axis  136  by greater than approximately 90 degrees, and the second angle is offset from the first axis by less than approximately 90 degrees. According to another example, the clamping arm comprises a sliding surface  180 , wherein the sliding surface is associated with a first dowel pin  185 , as illustrated again in  FIG. 2 . 
   The first dowel pin  185 , for example, is associated with the locating pin  120 , wherein the first dowel pin is operable to generally limit the rotation of the floating clamping arm  160  with respect to the body. In accordance with one example, the first dowel pin  185  extends downward into the generally hollow body  110  from the locating pin  120 , wherein the first dowel pin is generally fixed with respect to the locating pin. The first dowel pin  185 , for example, is operable to generally limit the rotation of the floating clamping arm  160  within the body  110 , wherein the sliding surface  180  associated with the floating clamping arm is operable to slidingly contact the first dowel pin, thus limiting the rotation of the floating clamping arm, yet allowing the floating clamping arm to generally translate along, or parallel to, the first axis  136 . 
   According to still another exemplary aspect of the present invention, the fixture  100  further comprises an anti-rotation mechanism  190  operatively associated with the drive pin  135 . The anti-rotation mechanism  190  generally limits a rotation of the drive pin  135  with respect to the body  110 . According to one example, the piston  140  and cylinder  145  are generally ovular when viewed perpendicular to the first axis  136 , wherein the generally ovular piston and cylinder generally define the anti-rotation mechanism  190 . Another exemplary anti-rotation mechanism  190  comprises one or more splines (not shown) associated with the drive pin  135  and the body  110 , wherein the one or more splines generally engage one another to generally permit a translation of the drive pin with respect to the body along the first axis  136 , while generally limiting a rotation of the drive pin with respect to the body about the first axis. Other anti-rotation mechanisms  190  such as pins (not shown) and corresponding slots (not shown) or any other device which generally limits the rotation of the drive pin  135  with respect to the body  110  are furthermore contemplated, and fall within the scope of the present invention. 
   According to another exemplary aspect of the present invention, the fixture  100  comprises a first port  192  and a second port  194  associated with a respective first end  196  and second end  197  of the cylinder  145 . The first port  192  and the second port  194  are operable to generally permit a selective flow of compressed gas (not shown) from a compressed gas source (not shown) therethrough. The first port  192  and the second port  194 , for example, are furthermore operable to selectively vent compressed gas from the cylinder  145 . The selective flow of compressed gas through one of the first port  192  or the second port  194  to an interior portion  198  of the cylinder  145 , for example, is operable to selectively translate the piston  140  within the cylinder, depending on which of the first port or the second port receives the compressed gas and which of the first port or the second port vents the compressed gas to atmosphere. Upon receiving the flow of compressed gas to the first port  192  or the second port  194 , the respective first end  196  or second end  197  of the cylinder  145  becomes pressurized, and the other one of first port or the second port is operable to vent the compressed gas to atmosphere from the respective first end or second end of the cylinder, thereby causing the translation of the piston  140  along the first axis  136  due to a differential in pressure. 
   In accordance with another exemplary aspect of the present invention,  FIGS. 5A–5F  illustrate the floating clamping arm  160  in a plurality of positions, wherein the floating clamping arm rotates and translates with respect to the body  110 . Beginning with  FIG. 5A , the floating clamping arm  160  is in the unclamped (locating) position  131 , wherein the workpiece  105  can be placed over the locating pin  120 , such that the locating pin protrudes through the hole  106  in the workpiece. In the locating position  131  (e.g., as further illustrated in  FIG. 2 ), the gripping portion  125  of the floating clamping arm  160  generally resides within the hollow portion  122  of the locating pin  120 , wherein the clamping arm does not interfere with the placement of the workpiece  105  over the locating pin. 
     FIG. 5B  illustrates a first intermediate position of the clamping arm  160  (e.g., when the compressed gas is introduced to the first port  192  and vented to atmosphere through the second port  194 , thereby causing the piston  140  and drive pin  135  to translate downwards toward the second end  197  of the cylinder  145 ). In the first intermediate position, the floating clamping arm  160  generally begins to rotate and translate with respect to the body  110 . The first cam follower  150  and second cam follower  155  generally slidingly engage the first cam surface  165  and second cam surface  170 , respectively, wherein the first dowel pin  185  generally limits the rotation of the floating clamping arm  160  by slidingly contacting the sliding surface  180  of the floating clamping arm. At the first intermediate position in  FIG. 5B , the gripping portion  125  of the floating clamping arm  160  generally begins to extend through the aperture  123  in the locating pin  120 . 
     FIG. 5C  illustrates a second intermediate position of the floating clamping arm  160 , wherein the first cam follower  150  continues to follow the first cam surface  165 , and a first sidewall  199  further generally limits the rotation of the clamping arm. The first sidewall  199 , for example, is associated with one or more of the hollow body  110  and the locating pin  120 . The clamping arm  160  slidingly engages the first sidewall  199  in the movements illustrated in  FIGS. 5C through 5F , wherein the first cam follower  150  generally follows the first cam surface  165 , and the second cam follower  155  generally remains stationary with respect to the second cam surface  170 , until the clamping arm  160  is in the clamped position  171  illustrated in  FIGS. 4 and 5F . Note that the gripping portion  125  of the clamping arm  160 , for example, contacts the workpiece  105  at the end surface  130  of the gripping portion, and does not contact the flange  107  of the workpiece due to the generally U-shaped gripping portion of the clamping arm. It should also be noted that the floating clamping arm  160  can also adapt to varying workpiece thicknesses (not shown) due to the relationship of the first cam follower  150  with first cam surface  165  and the second cam follower  155  with the second cam surface  170 . 
   In accordance with another exemplary aspect of the present invention, the floating clamping arm  160  can be easily removed from the fixture  110  without removing the first cam follower  150  or the second cam follower  155  from the body  110 . For example, referring again to  FIG. 3 , the floating clamping arm  160  further comprises a third cam surface  200 , wherein the first cam follower  150  is further operable to selectively engage the third cam surface. Upon engagement of the third cam surface  200  by the first cam follower  150 , the clamping arm  160  can be manually rotated and translated, such that the second cam surface  170  is operable to be disengaged from the second cam follower  155 . 
     FIGS. 6A–6E  illustrate an exemplary removal of the floating clamping arm  160  from the body  110  of the fixture  100 . Beginning with  FIG. 6A , the locating pin  120  and first dowel pin  185  are removed from the body. The first dowel pin  185 , in the present example, is integral to the locating pin  120 , wherein the removal of the locating pin incorporates a removal of the first dowel pin from the body  110 . With the removal of the locating pin  120  and first dowel pin  185  from the body, the sliding surface  180  of the floating clamping arm generally no longer limits the rotation of the clamping arm  160  within the body  110 . 
     FIG. 6B  illustrates a manual rotation of the floating clamping arm  160 , wherein the second cam surface  170  and second cam follower  155  are generally disengaged from one another by the rotation of the clamping arm about the first cam follower  150  in a first direction  205  (e.g., a counter-clockwise rotation) when the drive pin  135  is in the extended position  156 . In  FIG. 6C , the drive pin  135  is moved to the retracted position  157  (e.g., either manually or by compressed gas applied to the first port  192 ), wherein the second cam follower  155  is generally translated away from the first cam follower  150  (e.g., downwardly along the first axis  136 ). In  FIG. 6D , the floating clamping arm  160  is rotated in a second direction  210  (e.g., clockwise) about the first cam follower  150 , wherein the second direction is opposite the first direction  205  of  FIG. 6B . In  FIG. 6E , the first cam surface  165  and first cam follower  150  are generally disengaged from one another by a lateral translation of the clamping arm  160  (e.g., generally perpendicular to the first axis  136 ). The lateral translation of the floating clamping arm  160  illustrated in  FIG. 6E  may also include a rotation of the clamping arm in the first direction  205 . The floating clamping arm  160  can then be removed from the body  110  via a translation of the clamping arm which is generally parallel to the first axis  136 . In order to reinstall of the floating clamping arm  160  into the body  110 , the steps of  FIGS. 6A–6E , for example, are generally reversed. 
   It should also be noted that the floating clamping arm  160  of the present invention may be associated with a fixture  100  which does not comprise the locating pin  120  as mentioned above. For instance, the gripping portion  125  of the floating clamping arm  160  can extend outwardly from the body  110 , wherein the workpiece  105  can be generally clamped between the gripping portion  125  of the clamping arm  160  and the body  110 , and wherein the first sidewall  199  is associated with the body. Furthermore, the first dowel pin  185  can be associated with the body  110  (e.g., a removable pin or block removably attached to the body), rather than being associated with the locating pin assembly  120 . 
   In accordance with still another exemplary aspect of the present invention, as illustrated in  FIG. 2 , the locating and clamping fixture  100  further comprises a locking mechanism  210  associated with the drive pin  135 . The locking mechanism  210  is operable to generally maintain a position of the clamping arm  115  (e.g., the floating clamping arm  160 ) with respect to the body  110  in the event of a loss of the driving force F (e.g., a loss of compressed gas pressure to the first port  192 ). 
   The locking mechanism  210 , for example, comprises the drive pin  135  being separated into two segments; namely, a driver portion  215  coupled to the piston  140  and a driven portion  220  coupled to the clamping arm  115 . The driven portion  220 , for example, comprises a generally hollow outer shaft  225 , and the driver portion  215  comprises a generally solid inner shaft  226 , wherein the driver portion  215  is operable to translate within the driven portion  220  along the first axis  136 . The driver portion  215  and the driven portion  220  of the drive pin  135 , for example, are operably coupled to one another by a second dowel pin  230  associated with the driver portion, and a first slot  235  associated with the driven portion, wherein the second dowel pin is operable to translate along the first axis  136  between extents  240  associated with the first slot  235 . The first slot  235  and second dowel pin  230 , for example, are operable to provide a “rap” feature, where the driver portion  215  is operable to translate while the driven portion  220  remains generally stationary, and wherein the driver portion is operable to gain momentum prior to reaching one of the extents  240  of the first slot  235 . A gain in momentum prior to engaging the driven portion  220  is advantageous in that inertial forces associated with the clamping arm  115  or other components can be overcome by the momentum gained in the driver portion  220 . 
   The locking mechanism  210  may further comprise one or more rollers  245 , wherein the one or more rollers are operable to maintain a position of the clamping arm  115  in a case where the driving force F is lost. For example, the driver portion  215  of the drive pin  135  comprises an annular groove  250  at a one end  252  thereof, wherein a radius RAG of the annular groove is associated with a radius R R  of the one or more rollers  245 , and a width WAG of the annular groove is slightly less than twice the radius R R  of the one or more rollers. Furthermore, the body  110  comprises one or more lateral grooves  255  perpendicular to the first axis  136  and offset a predetermined amount from the first axis, wherein a radius R LG  of the one or more lateral grooves is further associated with the radius R R  of the one or more rollers  245 , and a width W LG  of the lateral groove is slightly less than twice the radius R R  of the one or more rollers. 
   Still further, the driven portion  220  of the drive pin  135  further comprises one or more channels  260  therein, wherein the one or more channels are associated with the respective one or more rollers  245 . Each of the one or more channels  260  has a generally rectangular cross section when viewed perpendicularly to the first axis  136 , wherein a width W C  of the one or more channels is slightly more than twice the radius R R  of the one or more rollers  245 . The one or more channels  260 , for example, are generally eccentric to the driven portion  220  of the drive pin  135  and are generally parallel to one or more rollers  245 . 
   The one or more rollers  245  are furthermore associated with the annular groove  250 , the one or more lateral grooves  255 , and the one or more channels  260 , wherein, depending upon a position of the driven portion  220  with respect to the body  110  along the first axis  136 , the one or more rollers  245  may reside within one or more of the annular groove  250 , the one or more lateral grooves  255 , and the one or more channels  260 . The locking mechanism  210 , for example, still further comprises the driven portion  220  of the drive pin  135  having a second slot  265  therein, wherein the second slot is generally parallel with the first axis  136  and radially offset from the first slot  235  by a predetermined amount (e.g., approximately 90 degrees about the first axis). Accordingly, the locking mechanism  210  yet further comprises a third dowel pin  270  associated with the body  110 , wherein an end portion  275  of the third dowel pin is operable to reside within the second slot  265 . The third dowel pin  270 , for example, generally permits the driven portion  220  of the drive pin  135  to translate between a first extent  280  and a second extent  285  of the second slot  265 . 
   In operation, the locking mechanism  210 , for example, is operable to generally maintain the position of the clamping arm when the driving force F is lost by an interface between the one or more rollers  245 , the drive pin  135 , and the one or more lateral grooves  255 .  FIGS. 5A–5F  further illustrate an exemplary operation of the locking mechanism  210 , wherein the driver portion  215  generally translates the one or more rollers  245  with respect to the body  110 . For example, in  FIGS. 5A–5C , the driver portion  215  and the driven portion  220  of the drive pin  135  are generally coupled by the one or more rollers  245  interfacing between the annular groove  250 , the one or more channels  260 , and a second sidewall  290  of the body  110 . During the translation of the drive pin  135  between  FIGS. 5A–5C , the driver portion  215  and the driven portion  220  generally translate in unison. In  FIG. 5D , the driver  215  begins to generally translate the one or more rollers  245  radially with respect to the first axis  136 , wherein the one or more rollers begin to translate out of the annular groove  250  and into the one or more lateral grooves  255 . 
   During the translation illustrated in  FIGS. 5D–5F , the driver portion  215  translates with respect to the driven portion  220 , wherein the first extent  280  of the second slot  265  generally causes the annular groove  250  to force the one or more rollers into the one or more lateral grooves  255  until the one or more rollers until no longer reside within the annular groove  250 .  FIG. 5F  illustrates a locked position of the drive pin  135 , wherein an outer diameter D of the driver portion  215  generally maintains the one or more rollers  245  within the one or more lateral grooves  255  and the one or more channels  260 . In the locked position, the driven portion  220 , and hence the floating clamping arm  160 , are generally not permitted to move upon a removal of the driving force F (e.g., a loss of pressure to the first port  192 ) due to the one or more rollers  245  being within the one or more lateral grooves by the outer diameter D of the driver portion  215 . 
   According to another exemplary aspect of the present invention, the locking mechanism  210  further comprises a resilient member  292 , a ball  294 , and one or more secondary grooves  296  associated with the driven member  220 . The resilient member  292  (e.g., a resilient polyurethane cylinder or a spring) and the ball  294  generally reside within a cylindrical bore  297  in the body  110 , wherein the ball is operable to selectively engage the one or more secondary grooves, depending on the position of the driven portion  220 . For example, the driven portion comprises secondary grooves  296 A and  296 B associated with the extended position and the retracted position of the drive pin  135 , respectively. The ball  294  is operable to engage secondary groove  296 A when the drive pin  135  (and hence, the driven portion  220 ) is in the extended position, and is further operable to engage secondary groove  296 B when the drive pin is in the retracted position. The ball  294  engaging the one or more secondary grooves  296  generally provides a limited force for maintaining the position of the driven portion  220  with respect to the body. 
   According to yet another exemplary aspect of the present invention, one or more cushioning pins  300  are associated with the piston  140 , wherein the one or more cushioning pins are operable to generally reduce a velocity of the piston with respect to the cylinder  145 . The one or more cushioning pins  300 , for example, are generally rigidly mounted to the piston  140 , wherein the one or more cushioning pins are operable to translate with the piston  140  with respect to the cylinder  145 . Each of the one or more cushioning pins is operable to linearly translate between an associated first position  305  (e.g., the extended position illustrated in  FIG. 2 ) and a second position  310  (e.g., the extended position of  FIG. 4 ) within the cylinder  145 . Each of the one or more cushioning pins  300 , for example, are furthermore associated with one or more cushioning holes  315 , wherein the one or more cushioning pins are operable to translate into and out of the respective one or more cushioning holes, wherein a diameter of the one or more cushioning holes  315  is larger than a diameter of the one or more cushioning pins  300 . For example, the one or more cushioning holes  315  are approximately 0.06 millimeters larger than a diameter of the one or more cushioning pins  300 . Furthermore, each of the one or more cushioning holes is associated with one or more of the first port  192  and the second port  194 , wherein the respective cushioning hole generally permits a fluid communication between the respective first port  192  and second port  194  and an interior portion  320  of the cylinder  145 . 
   As illustrated in  FIG. 2 , in the first position  305 , for example, the cushioning pin  300 A resides outside of the associated cushioning hole  315 A, wherein the compressed gas (not shown) is not impeded from flowing from between the interior portion  198  (e.g., the second end  197  of the cylinder  145 ) through the cushioning hole and the second port  194 . The cushioning pin  300 B in  FIG. 2 , for example, generally resides within the cushioning hole  315 B in the first position  305 , wherein fluid communication between the interior portion (e.g., the first end  196 ) of the cylinder  145  is significantly impeded. 
   An application of compressed gas to the first port  192  while venting the second port  194  to atmosphere, for example, will create a compressive force on the cushioning pin  315 B and the piston  140 , wherein the piston is generally forced downward by the compressed gas, thereby forcing the cushioning pin  300 B from the cushioning hole  315 B. Upon the application of the compressed gas to first port  192  (with second port  194  vented to atmosphere), the piston  140  is generally forced to the second position  310 , as illustrated in  FIG. 4 , wherein the cushioning pin  300 A is generally forced into the cushioning hole  315 A. When the cushioning pins  300  no longer reside in the respective cushioning holes  315 , the translation of the piston  140  with respect to the cylinder  145  occurs at a rate which is generally proportional to the pressure of the compressed gas. 
   During a transition between the first position  305  of  FIG. 2  and the second position  310  of  FIG. 4 , wherein one of the cushioning pins  300  begins to enter one of the cushioning holes  315 , the cushioning pin  300  entering the cushioning hole  315  generally acts as a needle valve, wherein a flow of the compressed gas through the respective cushioning hole is generally limited by the interference of the cushioning pin with a flow path of the compressed gas. For example, when an end  320 A of the cushioning pin  300 A begins to enter the cushioning hole  315 A, the flow of compressed gas through the cushioning hole is dramatically decreased, thereby slowing the translation of the piston  140  within the cylinder  145  until the piston reaches the second end  197  of the cylinder. Similarly, cushioning pin  300 B is operable to act in a similar fashion with respect to cushioning hole  315 B when compressed gas is applied to the second port  194  and the first port  192  is vented to atmosphere, wherein the translation of the piston  140  is slowed when the end  320 B of the cushioning pin  300 B enters the cushioning hole  315 B, until the piston reaches the first end  196  of the cylinder  145 . Such a slowing of the translation of the piston  140  is advantageous in both limiting inertial impact forces applied to the first end  196  and second end  198  of the cylinder  145  (e.g., thereby increasing a mean time before failure of the device), as well as, for example, limiting inertial impact forces applied to the workpiece  105 . 
   Although the invention has been shown and described with respect to certain aspects, equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described components (systems, devices, assemblies, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure that performs the function in the herein illustrated exemplary aspects of the invention. In addition, while a particular feature of the invention may have been disclosed with respect to only one of several aspects, such feature may be combined with one or more other features of the other aspects as may be desired and advantageous for any given or particular application. Furthermore, to the extent that the term “includes” is used in either the detailed description and the claims, such term is intended to be inclusive in a manner similar to the term “comprising.”