Abstract:
An improved quick-change collet chuck used with an existing single lane capping apparatus for gripping and installing container caps during the automated high-volume filling and capping process. The quick-change collet chuck allows quick and effortless swapping out of different size jaw sets for different size caps and minimizes interruption and downtime during the automated container capping processes. The quick-change collet chuck has a slim profile for low inertia so as not to interfere with high speed operation and accurate servo torquing. Another optional feature is shown in conjunction with the quick-change collet chuck to facilitate reversible operation when it is desirable to include on-the-fly cap removal and removal torque testing on the capping machine. This feature insures that the collet chuck cannot unscrew or spin loose from the spindle shaft after the quick-change collet is already locked in position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Priority of the present application is based on provisional application No. 60/070,039 filed Dec. 30, 1997. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the invention 
     The present invention relates to chucks for gripping workpieces and, more particularly, to a quick-change collet chuck for gripping and installing container caps during an automated high-volume filling and capping process. 
     2. Description of the Background 
     The filling and capping process generally entails supplying containers along a conveyor, automatically filling them at a filling station, and automatically capping them at a capping station. Various testing and control functions may be performed along the way, e.g., testing and control of fill volume, cap torque, conveyor velocity, etc. The apparatus which performs the process must be capable of accommodating a wide variety of containers and caps (both caps and containers may vary in size and shape), and this is accomplished by a universal chuck which allows quick and easy grasping and manipulation of different cap sizes. 
     Current common methodology for screw cap positioning and torquing include the following types of chucks: 
     Tapered Chuck 
     Friction Disk Chuck 
     Donut Chuck 
     Segmented Chuck 
     The action of the Tapered Chuck and the Friction Disk chucks is to apply axial (downward) force to generate the friction drive between the cap top (rim) and the chuck taper or friction disk. Having to avoid damage to the container, cap, and/or thread the axial force is limited. Thus tapered chucks and friction disc chucks can only handle a limited type of caps in relatively low torque applications which severely restricts the usage of these chucks. Another disadvantage of these chucks is their possible contamination by their own (or from the caps) particulates. Shavings may prevent required torque transfer since the driving axial force is limited in order not to damage the container and/or thread. These shavings can cause slippage that will perpetuate the problem. Simple friction drives such as the Tapered Chuck and the Friction Disk Chuck are not desirable in pharmaceutical clean packaging environments due to potential particulate generation from slippage. 
     The Donut Chuck includes a urethane ring (open center diameter matched in size to the cap) that, when a concentric cylinder is actuated, swells inward to clamp (radial pressure) on the outside of the cap thus enabling torque transfer as required. This is a friction drive but the friction force is generated not by axial but by a radial force compressing the cap. Normally this allows for a significantly higher torque range compared to the simple friction drives mentioned above. No axial force to risk the damage of the container or threads. However, there are a significant number of parts to be changed when changing from one cap size to another, enough that often the complete chuck is exchanged. Besides the tool requirement to do this, there is significant cost involved. The Donut Chuck has a working torque range good for up to medium (average) torque requirements (The particulate generation is minimal due to the clamping force being well in excess to what is required for transfer of the normal required torque thus resulting in no slippage between the cap and the donut). 
     The Segmented Chuck concept is specifically for the high torque range caps that typically have more severe serrations or other significant protrusions on the outside cap (radial) surface. The segmented chuck may, for instance, include a 3 piece segmented chuck jaw set (each segment occupying 120 degrees). However, this 3 piece segmented design is very heavy and clumsy, and it suffers from somewhat unstable jaw segments. In addition, the multi-segmented jaw set concept is very expensive to manufacture, and it does not lend itself to quick changing for different size caps. The chuck jaws are designed to match the cap outside profile and by a true interlock (when the jaws close) to facilitate positive (i.e. non-friction) drive for high torque requirements. Due to the expensive segmented die jaws concept of positive locking being very different from the Donut Chuck friction concept, this chuck does not lend itself economically to any simple applications. Again the change parts are enough trouble that for each cap size a complete new chuck is the practical solution. A whole chuck (inclusive of jaws) needs to be changed. Moreover, the mass of the three piece segmented chuck results in a high inertia which interferes with high speed operation. The chuck is servo driven and the servo motor provides positive feedback on the power required to turn/torque the cap. The high inertia of the chuck contaminates this data and limits the torquing speeds (and the overall production rates). A lower inertia results in more accurate torquing and higher production speeds. 
     It would be a great advantage to have a quick-change low-inertia collet-type chuck to allow quick and effortless swapping out of different size jaw sets for different size caps. 
     The Collet Chuck concept of a universal chuck to actuate a quick-change one-part collet as the only change part is far superior to the Donut Chuck and the Segmented Jaw Chuck since collets can be made to work the whole working range of these other two chucks. A low cost urethane lined collet will drive the caps with lower torque requirements. A machined contact profile collet will drive the caps with high torque requirements (positive interlocking with the external cap profile). Even asymmetric caps could be clamped in custom collets without requiring a special chuck change (The collet orientation relative to the chuck is always an exact repeat and servo drive allows an exact chuck orientation repeat). Preferably, there should be virtually no down time (or skill level) associated with the collet change. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an improved quick-change collet chuck for use in handling virtually any work piece. 
     It is a more specific object to provide a quick-change collet chuck to allow quick and effortless swapping out of different size jaw sets for different size caps while minimizing any interruption of the container capping process. 
     It is still another object to provide a quick-change collet chuck which incorporates a unitary jaw set for increased durability and reliability, lower manufacturing cost, and greater ease of handling. 
     It is a further object to provide a chuck as described above with the lowest inertia possible so as not to interfere with high speed operation and accurate servo torquing. 
     It is still another object to insure that the collet chuck cannot unscrew or spin loose from the spindle shaft after the quick-change collet is already locked in position, thereby facilitating reversible operation when it is desirable to include cap removal and removal torque testing on the capping machine. 
     Additional objects include stainless construction and a no-tools quick-change design. 
     In accordance with the above objects, an improved quick-change collet chuck is described for use in an existing single lane capping apparatus for gripping and installing container caps during the automated high-volume filling and capping process. The quick-change collet chuck allows quick and effortless swapping out of different size jaw sets for different size caps while minimizing interruption and down time of the automated container capping processes. The quick-change collet chuck has a slim profile for low inertia so as not to interfere with high speed operation and accurate servo-torquing. Another feature is shown in conjunction with the quick-change collet chuck to facilitate reversible operation when it is desirable to include cap removal and removal torque testing on the capping machine. This feature insures that the collet chuck and collet cannot unscrew or spin loose from the spindle shaft after the quick-change collet is already locked in position. It would be a great advantage to have a quick-change low-inertia collet-type chuck to allow quick and effortless swapping out of different size jaw sets for different size caps. 
     The quick change collet chuck of the present invention was specifically developed for cap positioning and torquing in pharmaceutical Clean Room Class 100, although it should be understood that the inventive concept may apply in many other contexts. The Class 100 refers to the quantity of particles permitted (in the exposed product zone): 100 particles per cubic foot between the 0.5 micron and 5-micron size. This means special clothing and gloves for operators to reduce particulate generation. This aspect comes into play in the chuck design as well. The major source of particulate generation in the typical Clean Room is the human operator. Any unnecessary movements by the operator/mechanic in a Class 100 room results in (relatively) huge particulate generation. Simple, light, no-tools quick-change tooling is an extremely effective way of avoiding this type of particulate generation. For changeover the “J” lock in the present chuck is as simple as can be: push, twist by ⅛ turn, let go. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment and certain modifications thereof when taken together with the accompanying drawings in which: 
     FIG. 1 is a perspective view of an existing single lane capping apparatus  10  incorporating a quick-change collet chuck  20  according to the present invention for gripping and installing container caps during the automated high-volume filling and capping process. 
     FIG. 2 is a side view of the single lane capping apparatus  10  with quick-change collet chuck  20  of FIG.  1 . 
     FIG. 3 is a side close-up view of the quick-change collet chuck  20  of FIGS. 1 and 2. 
     FIG. 4 is an upwardly directed close-up view of the quick-change collet chuck  20  of FIGS.  1 - 3 . 
     FIG. 5 is a side sectional view of the quick-change collet chuck  20  of FIGS.  1 - 4  without collet  22 . 
     FIG. 6 is a side sectional view of the quick-change collet chuck  20  with collet  22 . 
     FIGS. 7,  8  and  9  are a side sectional view, a side perspective view, and a top view, respectively, of Piston  101 . 
     FIGS. 10,  11 ,  12  and  13  are a side sectional view, a side perspective view, a bottom view, and a top view, respectively, of the Bell  102  which serves as the piston gland and wall. 
     FIGS. 14,  15 ,  16 ,  17  and  18  are a side sectional view, a side sectional view rotated by 90 degrees, a side perspective view, a bottom view, and a top view, respectively, of the Shaft  103 . 
     FIGS. 19 and 20 are a side sectional view, and a top view, respectively, of the Bushing  104 . 
     FIGS. 21,  22 ,  23 ,  24 ,  25 ,  26 ,  27  and  28  are a front perspective view, a close-up perspective view at the top, a close-up perspective view at the bottom, a side sectional view, a side perspective view, a side sectional view rotated by 90 degrees, a top view, and a bottom view, respectively, of the collet  22  according to one embodiment of the present invention. 
     FIG. 29 is a profile drawing illustrating another embodiment of collet  22  in which the hook of channel  20  is eliminated. 
     FIGS. 30,  31  and  32  show a top perspective view, an end cross-section, and a side cut-away view, respectively, of a two-position release slide pin for use with the collet  22  of FIG. 29 which eliminates the need for the hook of channel  260  without sacrificing the quick-release feature. 
     FIG. 33 is a side cut-away drawing illustrating the placement of a conventional ball-detent mechanism  140  for cooperation with the quick release pin of FIGS.  30 - 32  by insertion into the hollowed lower tip of Shaft  103 , thereby helping to eliminate the need for the hook of channel  260  without sacrificing the quick-release feature. 
     FIG. 34 illustrates the use of a “draw bolt”  320  to effect reversibility when cap removal and removal torque testing is desirable. Draw bolt  320  may be used with any of the above collet/chuck embodiments. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a perspective view of an existing single lane capping apparatus  10  incorporating a quick-change collet chuck  20  according to the present invention for gripping and installing container caps during the automated high-volume filling and capping process. Bottles  40  or other containers are urged along a conveyor to a capping position. The capping apparatus  10  is supported on adjustable air pistons  30 , and it extends the quick-change collet chuck  20  downward toward the bottle  40 . 
     FIG. 2 is a side view of the single lane capping apparatus  10  with quick-change collet chuck  20  of FIG.  1 . During a capping maneuver, a cap  42  is rotated into position on a pivoting arm  44  and upwardly presented into the open quick-change collet chuck  20 . Bottle cap  42  is clamped within the jaws of the collet  22  inserted in quick-change collet chuck  20 . Once the bottle is properly positioned, the capping apparatus  10  extends the quick-change collet chuck  20  downward to seat the bottle cap  42  on the neck of the bottle  40 , and then rotates the collet chuck  20  to screw the bottle cap  42  onto the neck of bottle  40 . All movements of the capping apparatus  10  are electronically controlled in accordance with pressure/torque feedback to insure that the cap  42  is properly seated and screwed onto the bottle  40 . 
     FIG. 3 is a side close-up view of the quick-change collet chuck  20  of FIGS. 1 and 2. In the illustrated position, a cap  42  has been lifted by pivoting arm  44  and is held in the grip of the collet  22  prior to placement on the neck of bottle  40  (the arm  44  is rotated out of harm&#39;s way prior to the chuck lowering to place the cap  42  on the bottle  40 ). 
     FIG. 4 is an upwardly directed close-up view of the quick-change collet chuck  20  of FIGS.  1 - 3 . Again, cap  42  has been lifted up by arm  44  and is held in the grip of the collet  22  prior to placement on the neck of bottle  40 . 
     FIG. 5 is a side sectional view of the quick-change collet chuck  20  without collet  22 . 
     FIG. 6 is a side sectional view of the quick-change collet chuck  20  of FIGS.  1 - 5  with collet  22  inserted therein. The collet  22  is a generally cylindrical unitary member formed with an upper mounting collar, a downwardly flared mid section, and a lower cap gripping section. The downwardly flared mid section and lower cap gripping section are interrupted by a plurality of longitudinal notches which give the cap gripping section the ability to expand or contract to release/grip a bottle cap inserted therein. 
     With reference to FIGS. 5 and 6, the chuck consists of the Shaft  103  that connects with the hollow drive shaft supplied with the existing capping apparatus  10 . Shaft  103  is drilled laterally toward its lower extremity to receive a pin  105 . Preferably, a stepped pin  105  is used to ensure unique orientation as will be described. Quick-release collet  22  is inserted over the end of shaft  103  and is captured by pin  105 , thereby retaining the collet  22 . Shaft  103  is formed with a deep central bore (dotted lines) to bring an external air supply inside the collet chuck  20 , and the upper end of Shaft  103  is drilled laterally to provide an air passage  110  for bleeding air through the central bore. The air supply is directed into a cavity  711  existing between a Bell  102  and the face is of Piston  101 . When the air supply is activated the cavity  711  is pressurized and piston  101  is urged downward. A Bushing  104  is slipped over Shaft  103 , and this may be formed of Delrin plastic or other suitable bushing material. As seen in FIG. 6, Bushing  104  serves to retain a compression spring  106  that is required for return of piston  101  (after the air pressure is removed). Bushing  104  also serves as a guide for piston  101  to prevent racking and serves as a pressure pad for latching the quick-release collet  22 . 
     Piston  101  comprises an upper disk with a unitary extension sleeve protruding downwardly. The disk of piston  101  is machined with an inner O-ring groove for housing an inner O-ring  107  (or alternatively, a cup seal) that seals against the Shaft  103 , and with an outer O-ring groove for housing an outer O-ring  108  that seals against the inner wall of a Bell  102 . The inside bore of the extension sleeve of Piston  101  also serves as a guide surface for the Bushing  104  to prevent racking of the piston. The Bell  102  serves as the piston gland and wall. 
     The action of the quick-change collet chuck  20  is as follows. Air pressure from an external source is applied though air passage  110  and through the upper bore in Shaft  103 , and air trapped in the cavity  711  between the Bell  102  and Piston  101  face forces the Piston  101  downward. The sleeve of the Piston  101  transfers the force produced to the downwardly flared mid section of collet  22 . As the Piston  101  is forced out, the annular lower lip of the Piston  101  sleeve forces the collet  22  to flex inward (contract) as it slides along the flared mid section of collet  22 . Once the air pressure is removed, the return spring  106  forces the Piston  101  upward until it reseats against the limiting wall of Bell  102 , and the collet  22  is allowed to flex open again as the sleeve retracts off the flared mid section of collet  22 . 
     FIGS. 7,  8  and  9  are a side sectional view, a side perspective view, and a top view, respectively, of Piston  10   1  showing the upper disk  111  with unitary extension sleeve  112  protruding downwardly. Again, the disk  111  of piston  101  is machined with an inner O-ring groove  114  for housing inner O-ring  107 , and an outer O-ring groove  113  for housing outer O-ring  108 . The inside bore of the extension sleeve  112  of Piston  101  is a smooth and uniform guide surface for Bushing  104 , and the bottom rim is thicker and rounded to provide a bearing surface. 
     FIGS. 10,  11 ,  12  and  13  are a side sectional view, a side perspective view, a top view, and a bottom view, respectively, of the Bell  102  which serves as the piston gland and wall. Bell  102  is a generally cylindrical hollow cap which covers and seals the upper end of Piston  101 . Bell  102  is formed with a reduced-diameter neck  121  having a central through-bore for receiving Shaft  103 . The other end is an expanded collar  122  having a smooth inner wall for slidable insertion onto the upper end of Piston  101  and over O-ring  108 . 
     FIGS. 14,  15 ,  16 ,  17  and  18  are a side sectional view, a side sectional view rotated by 90 degrees, a side perspective view, a bottom view, and a top view, respectively, of the Shaft  103 . Shaft  103  is a generally cylindrical member that is drilled lengthwise to form a central air passage  131 , the mouth of which connects with a hollow drive shaft supplied with the existing capping apparatus  10 . Shaft  103  is also drilled to form a lateral bore  133  toward its lower extremity to receive pin  105 . Shaft  103  is also drilled to form an upper lateral bore  132  toward its upper extremity. Upper bore  132  communicates with the central passage  131  to bleed air outwardly. In operation, Bushing  104  is inserted over the Shaft  103 . As seen in FIGS. 15 and 16, shaft  103  is formed with a raised section  135  around the lateral bore  133  for reinforcement of the pin to be inserted therein and to provide a stop for Bushing  104 . 
     FIGS. 19 and 20 are a side sectional view and a top view, respectively, of the Bushing  104 . Bushing  104  is formed in the shape of a cylindrical collar with protruding lower flange and is made of Delrin plastic or other suitable material. Bushing  104  is sized for insertion over the Shaft  103  and serves to retain compression spring  106 . Bushing  104  also serves as a guide for piston  101  to prevent racking and serves as a pressure pad for latching the quick-release collet  22 . 
     FIG. 21 is a front perspective view of the quicl-release collet  22  according to one embodiment of the present invention. The collet  22  is a generally cylindrical unitary member formed with an upper mounting collar  210 , a downwardly flared mid section  220 , and a lower cap gripping section  230 . The downwardly flared mid section  220  and lower cap gripping section  230  are interrupted by a plurality of longitudinal notches  240  which give the cap gripping section  230  the ability to expand or contract to release/grip a bottle cap inserted therein. 
     FIG. 22 is a close-up side perspective view of the upper mounting collar  210  of collet  22 . Upper mounting collar  210  is formed with a lateral through-bore  250 , and with opposing hooked or “J-lock” mounting channels  260  for effecting the quick-change feature. Each of the J-lock mounting channels  260  has an open mouth leading to a closed hook. The stepped pin  105  comprises a cylindrical main section having a larger diameter r 1 , and a cylindrical end section having a slightly smaller diameter r 2 . This stepped pin configuration is used in conjunction with two differently-sized J-lock mounting channels  260  to ensure a unique orientation of the pin  105 . Specifically, the closed hook of one J-lock mounting channel  260  is formed with a larger diameter w 1  that conforms to the diameter R 1  of the main section of pin  105 , while the opposing J-lock mounting channel  260  is formed with a smaller diameter w 2  that conforms to the diameter r 2  of the end section of pin  105 . This way, after the pin  105  has been inserted through the open mouths of both J-lock mounting channels  260 , the collet  22  can only be twisted to properly seat the stepped pin  105  in the closed hooks if the two differently-sized J-lock mounting channels  260  are properly oriented with respect to the two sections of pin  105 . This ensures the proper orientation. 
     In operation, and with additional reference back to FIG. 6, pin  105  is inserted through the shaft  103 . The quick-release collet  22  is then inserted over the end of shaft  103  until the ends of pin  105  enter the mouths of the J-lock mounting channel  260  of collet  22 . The collet  22  is rotated and the ends of pin  105  are guided around and into the hooks of channels  260  and become captive therein, thereby retaining the collet  22 . All the while, the chuck piston return spring  106  doubles as a latching spring for the collet  22 , e.g., chuck piston return spring  106  exerts a downward pressure on collet  22  and insures that the mounting channel  260  remains hooked on pin  105 . Once the chuck cylinder is pressurized, the force it produces will re-enforce the latching action of spring  106  and the collet is positively retained. Once the pressure is removed from the chuck, the collet  22  is easily and manually removed by ⅛-turn push-turn-pull motion. This is ideal because the collet change does not require tools, time, or thought, and it avoids loose parts which can be lost or misplaced. 
     FIG. 23 is a side close-up perspective view of the lower cap gripping section  230  of collet  22  according to one embodiment of the present invention. As is known in the art, the inner jaws of the lower cap gripping section  230  may be serrated as shown, or they may be lined with a rubber gripping material as desired depending on the particular caps to be installed. 
     FIGS. 24,  25 ,  26 ,  27  and  28  are a side sectional view, a side perspective view, a side perspective view rotated by 90 degrees, a top view, and a bottom view, respectively, of the collet  22  according to the present invention. It is that noteworthy that the design of the above-described collet chuck  20  insures that the Shaft  103  remains fully behind the collet  22  thus allowing a smaller piston inside diameter. Using lateral through-bore  250  and J-lock mounting channel  260  for effecting the quick-change feature, the built-in concentric chuck cylinder is behind the collet  22  rather than around it. Consequently, the “flywheel” effect (rotational momentum) is minimized by keeping the mass as close to the rotational axis as possible. The inertia is calculated as proportional to MR 2  (mass x radius squared). Calculations indicate that the inertia of the present QuickChange Collet Chuck design is 27% of competing segmented jaw chucks, and the mass is only 40%. This very low inertia becomes very important in achieving high production rates with accurate application torque. Most screw caps are applied in 1½ to 2½ turns. The fastest most accurate application algorithm for cap torquing is to use a servo motor to rotate the cap at high speed for the first (approximately) 1¼ turn and than abruptly slow to low speed to finish the torquing accurately (better resolution). The servo motor is capable of giving feedback of the current required to rotate the cap at any instant of time. Any large inertia contaminates this feedback information since it no longer only represents the power required to turn the cap at the low speed. If the cap is fully torqued at exactly 1½ turns the flywheel effect can easily skew the feedback (in comparison to 2½ turns with 1 full turn at low speed). To achieve the higher production rates the initial high rotational speed is crucial. This all boils down into a need for low inertia of all rotating mass, and the present invention meets the need. The outside diameter will be small as well, keeping the inertia low. The lower inertia results in more accurate torquing and higher production speeds because there is less interference with high speed operation and feedback power reading of the servo motor. 
     FIG. 29 is a profile drawing illustrating a second embodiment of collet  322  in which the hook or J-lock design of channel  20  is eliminated. The J-lock is not necessary with the use of a modified 2-position slide release pin as will be described, yet this also accomplishes the quick-release feature. 
     FIGS. 30,  31  and  32  show a top perspective view, an end cross-section, and a side cut-away view, respectively, of the two-position slide release pin  105  for use with the collet  322  of FIG.  29 . This eliminates the need for the hook or J-lock of channel  260  without sacrificing the quick-change feature. Collet  322  can be easily and manually changed without tools by shifting pin  105 . Two-position slide release pin  105  is sized for insertion in the lateral through-bore  360  in upper mounting collar  310  of collet  322 . A detent channel  330  is centrally located, and this is preferably a shallow notch leading to a slightly deeper pocket. 
     As seen in FIG.  30  and combined with reference to FIG. 29, pin  105  incorporates opposing side notches  320  at each end which correspond to the walls of upper mounting collar  310 . These side notches  320  allow the collet  333  to be removed when they are aligned with the vertical slot leading into the lateral through-bore  360  in the collet  322 . Thus, when slid to an open position, the opposing side notches  320  form a narrow cross-section to allow easy insertion or removal of collet  322 . However, when slid to a closed position the opposing side notches  320  form a broader cross-section to lock the collet  322  in position. 
     FIG. 33 is a side cut-away drawing illustrating the placement of a detent mechanism for cooperation with the quick release pin  105  of FIGS.  30 - 32 . The detent channel  330  cooperates with a detent pin  335  which can be mounted inside the lower end of Shaft  103 . The detent pin  335  is a simple spring-loaded detent pin with a pointed tip as shown. 
     When pin  105  is inserted laterally into the piston  103 , the detent pin  335  enters detent channel  330  and seats the pin  105  upon reaching the deeper pocket. Once seated in the deeper pocket of detent channel  330 , the detent pin  335  holds the slide pin  105  in closed position and thereby locks collet  322  in position. The pin  105  can be conveniently and manually slid from the locked or closed position to the unlocked or open position, thereby enabling quick-change insertion/removal of collet  22  without tools. Given the two-position slide release pin  105  of FIGS.  30 - 32  with detent pin of FIG. 33, the collet itself need not be press and twist-on embodiment shown in FIGS.  21 - 28 . 
     Another feature may be incorporated into the above-described collet chuck to facilitate reversible operation. This is significant when it is desirable to include cap removal and removal torque testing on the capping machine  10 . This feature requires that the chuck  20  cannot unscrew or spin loose from the spindle shaft since the quick-change collet  22  is already locked in position by the above-described quick-release mechanisms. As shown in FIG. 34, the reversibility is accomplished with an internally threaded “draw bolt”  320  that screw-attaches to the collet chuck  20  and tightens, thereby allowing it to be pre-loaded well in excess of the working application torque by at least a factor of 10. This facilitates reversibility by far exceeding the “break-loose” torque between the existing spindle shaft and chuck shaft (the rotary spline assembly and spindle shaft are existing components of a single lane capping apparatus. The collet chuck assembly  20  itself remains unchanged but reversibility is facilitated. Draw bolt  320  may be used with any of the above-described collet/chuck embodiments. 
     Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.