Abstract:
A modular endforming mechanism for modifying an end of a thin-walled malleable tube is herein disclosed. The modular endformer comprises a gripping module having a collet means for grasping a tube inserted into the gripping module. The gripping module may be coupled to one of an expansion module and a reducing/flaring modular. The expansion module is constructed and arranged to actuate a sizing mandrel, which is inserted into the interior of the end of a tube to expand the diameter of the end of that tube. A forming insert works in conjunction with the sizing mandrel to limit the expansion of the tube diameter under the influence of the sizing mandrel. The reducing/flaring modular is similarly constructed and arranged to actuate a forming die having a tapered inner surface that engages the exterior of a tube clamped in the collet means of the griping modular so as to reduce the outer diameter of the tube and a flaring tube having a frustoconical surface that engages the interior of the tube at a predetermined angle to flare the end of that tube.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application claims priority from U.S. provisional patent application No. 60/205,950, filed on May. 19, 2000. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a modular end-forming device, or end former, used to modify the geometry of the end of a tube. More particularly, the present invention relates to a modular device that can expand, reduce, or flare the ends of tubes having differing diameters and wall thicknesses such as those tubes used in air conditioning coils. 
     BACKGROUND OF THE INVENTION 
     Often it is necessary to modify the geometry of an end of a tube to facilitate the creation of a joint such as a slip joint used to join two lengths of tubing. Similarly, it is often necessary to flare the end of a tube for use in a compression fitting. Tubes that are modified in these manners are typically thin-walled and made of a malleable material such as copper. 
     One of the problems which is encountered in the assembly of tube devices is the need to quickly and efficiently join tubes together, either when the unit is assembled in the field or when repairs are made. Even in factory assembly, coil units require tubes to be joined and this procedure needs to be accomplished as effectively and efficiently as possible. 
     Fluid pressure devices operated by hydraulic pressure or pneumatic pressure are known, particularly for expanding tubes such as those used in air conditioning coils and the like. Several hydraulic devices have been developed which are suitable for tightly gripping one end of an elongated tube while simultaneously delivering a tube expanding fluid. Among these are U.S. Pat. Nos. 3,505,846; 3,813,751, 3,962,769; and 4,189,162. None of these patents describe devices which are suitable for expanding the ends of tubes. 
     Other prior art devices which are used to expand the ends of tubes are devices which include a split finger means which is inserted in the tube. As the split fingers expand or flair out the end of the tube, material is squeezed between the fingers, leaving longitudinally extending ridges or raised portions. These raised portions of material cause several problems, both in obtaining a good junction and strong seal, and in requiring the use of much more silver solder or other sealing material. 
     U.S. Pat. No. 5,134,872, issued to Paul N. Ose and hereby incorporated by reference and commonly assigned herewith, discloses a device for expanding the inner diameter of tube ends having varying wall thicknesses. However, this device is capable of expanding a tube diameter only and is not capable of reducing a tube&#39;s diameter or flaring the end of a tube. 
     Accordingly, it is an object of the present invention to provide a modular mechanism that utilizes interchangeable modules and tooling to effect the expansion, reduction, and flaring of tube ends. Another object of this invention is provide a modular mechanism that may modify tubes of various diameters and wall thicknesses. 
     These and other objectives and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. 
     SUMMARY OF THE INVENTION 
     A modular endformer according the present invention is capable of modifying a thin walled malleable tube by reducing the diameter thereof, expanding the diameter thereof, and by flaring or belling the end of the tube. In achieving this functionality, the endformer of the present invention is constructed and arranged to utilize common structures to alternatively actuate and operate an expanding tool, a reducing tool, and a flaring tool. As can be appreciated, the dimensions of the expansion tool, reducing tool and flaring tool may be varied to accommodate variously sized tubes. 
     The endformer of the present invention essentially comprises a body having a piston structure and a collet mechanism slidably disposed therein. The body has first and second inlet structures for a source of fluid under pressure. The body also has a tube-receiving end that allows a tube to be inserted therein. 
     The piston structure is longitudinally movable within the body between a first, retracted position and a second, extended position. The piston structure is moved to its first position by the introduction of a pressurized fluid into the first inlet structure, and is moved to its second position by introducing the pressurized fluid into the second inlet structure. The piston structure has coupled thereto an adjustment mechanism that provides for controlling the distance traveled by the piston structure between its first and second positions. The piston structure and adjustment mechanisms are constructed and arranged to actuate one of the aforementioned expanding tool, reducing tool, and flaring tool. 
     The collet mechanism is disposed within the body adjacent the tube receiving end thereof and engages and clamps a tube end within the body. The collet mechanism is arranged such that the tube end is engaged at a location spaced apart from the end of the tube. The collet mechanism is actuated to grasp the tube by the piston structure when pressurized fluid is introduced into the first inlet structure and actuated to release the tube by the pressurized fluid introduced into the body by the second inlet structure. 
     Preferably, the body of the endformer will comprise a first half and a second half with the piston structure of the endformer being disposed substantially within the first half of the endformer and the collet mechanism being disposed substantially within the second half of the end former. 
     The piston structure of the present invention essentially comprises a primary piston that is slidably received within a bore formed in an actuator piston that is itself slidably received within the body of the endformer. The primary piston moves longitudinally within the actuator piston between a first position and a second position under the influence of pressurized fluids introduced through the first and second inlet structures, respectively. The primary piston actuates the expanding tool as the primary piston moves from its first position to its second position. The actuator piston simultaneously actuates the collet mechanism so that the collet mechanism will grasp and hold the tube as the expanding tool engages the tube. 
     The expanding tool used with the present invention comprises a sizing mandrel coupled to the primary piston and a forming insert disposed within the body generally adjacent the tube receiving end thereof. The forming insert has an interior bore of a predetermined size formed therethrough that is sized to receive therein an end of the tube that will be modified. The sizing mandrel is arranged to be inserted into the tube end that is disposed within the forming insert as the primary piston moves from its first, retracted, position to its second, extended position, thereby expanding the diameter of the tube end to that of the forming insert. 
     The reduction tool of the endformer of the present invention comprises a forming die and a removal shoulder that are coupled to the piston structure of the endformer. The forming die is operatively coupled to the end of the primary piston and the removal shoulder is coupled to the end of an adjusting mechanism that is itself operatively coupled to the primary piston independent of the forming die. The forming die has an interior tapered bore of a predetermined size and shape that when addressed to the end of a tube received within the body of the endformer, will reduce the outer diameter thereof. The forming die is actuated into contact with the end of a tube as the primary piston moves from its first position to its second position. As the primary piston moves back to its first, retracted position from its second, extended position, the removal shoulder acts to push a tube out of the tapered bore of the forming die as the forming die moves past the removing shoulder. 
     The flaring tool that is used with the endformer of the present invention comprises a flaring die that is coupled to the piston structure. The flaring die has a frustoconical surface having a predetermined angle that is constructed and arranged to engage the end of a tube received within the tube receiving end of the body as the piston structure moves from a first retracted position to a second extended position. When it operatively addresses the end of the tube, the frustoconical surface of the flaring die acts to flare out the end of the tube. 
     The collet mechanism of the endformer of the present invention essentially comprises a plurality of collet jaws that are operatively coupled to the piston structure of the endformer such that the collet jaws may travel longitudinally therewith. The collet jaws are further constructed and arranged to move in a radial direction with regard to the piston structure so as to permit the collet jaws to come into clamping contact with a tube end inserted into the tube receiving end of the body of the endformer. The collet mechanism may be used with each of the expanding tool, reducing tool, and flaring tool. 
     A preferred embodiment of the collet mechanism of the present invention comprises a collet actuator, a return collet and a plurality of collet jaws. The collet actuator is slidably disposed within a bore formed through a first section of the endformer. The return collar is also slidably disposed within the bore formed through the first section of the endformer and is coupled to the collet actuator so as to move therewith. The collet jaws are operatively coupled to the collet actuator and are constructed and arranged to move longitudinally with the collet actuator and to also move radially with respect to the collet actuator. The collet jaws of the endformer move radially inwardly so as to clamp a tube received within the body of the endformer when the collet jaws are brought into contact with an inner surface of the body of the endformer. This occurs as the collet mechanism moves from its first, retracted position, to its second, extended position. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of the modular end former of the present invention along with a selection of end forming tooling that may be used therewith; 
     FIG. 2 is a sectional view of a side elevation of the gripping module of the end former; 
     FIG. 3 is a sectional view of a side elevation of an expansion module of the end former of FIG. 1; 
     FIG. 4 is a sectional view of a side elevation of a reducing module of the end former of FIG. 1; 
     FIG. 5 is a sectional view of a side elevation of an assembled end former configured with an expansion module and a gripping module; 
     FIG. 6 is a sectional view of a side elevation of an assembled end former configured with a reducing module and a gripping module; 
     FIGS. 7 a  and  7   b  are partial cutaway views of a side elevation of an assembled end former configured with an expanding module and a gripping module and having a forming insert and sizing mandrel installed therein; and, 
     FIGS. 8 a  and  8   b  are partial cutaway views of side elevations of an assembled end former configured with a reducing/flaring module and wherein a removal shoulder and forming die are installed in the end former of FIG. 8 a  and a flaring tool is installed in the end former of FIG. 8 b.   
    
    
     DETAILED DESCRIPTION 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims. 
     Referring to FIG. 1, it can be seen that the modular end former  10  of the present invention comprises a gripping module  12 , an expanding module  14 , and a reducing module  16 . The end former  10  may be configured to expand the end of a tube  11  by bolting the expanding module  14  to the gripping module  12  as illustrated in FIG.  5 . Similarly, the end former  10  may be configured to expand or flare the end of a tube  11  by bolting the reducing module  16  to the gripping module  12  as illustrated in FIG.  6 . Also illustrated in FIG. 1 is an expansion tool  18  that is constructed and arranged for use with the expanding module  14 . The expansion tool  18  comprises a piston extension  20 , a forming insert  22 , and a sizing mandrel  24 , the construction and use thereof being described in greater detail herein below. 
     Also illustrated is a reducing tool  26  that is used with the reducing module  16  to reduce the diameter of the end of a tube  11 . The reducing tool  26  is comprised of a forming die  28  and removal shoulder  30 , the construction and use thereof being described in more detail herein below. A flaring tool or flaring die  25  is illustrated in FIG. 8 b . It is to be noted that by varying the dimensions of the respective expansion, reducing, and flaring tools  18 ,  20 , and  25 , it is possible to utilize the modular end former  10  of the present invention with diverse tubes  11  having varying diameters and wall thickness. 
     FIG. 2 illustrates in more detail the construction of the gripping module of the end former  10 . The gripping module  12  is made up of a body  32  having a base  34  and an end  36 . The outer surface of the end  36  is threaded so that a front cap  38  may be threadedly secured to the body  32  of the gripping module  12 . The body  32  and front cap  38  have a bore formed therethrough that is sized to receive a collet means for grasping and retaining the end of a tube  11  that is to be modified. The collet means comprises a plurality of collets or collet jaws  40  that are secured to a collet actuator  46 . Each of the collets  40  has a tab  42  extending from the base thereof that is slidably received in a radially oriented slot formed in the end face of the collet actuator  46 . Each of the tabs  42  and their corresponding radial slots  44  have in this embodiment a “T” shape that constrain the collets  40  to move axially along with the collet actuator  46 . The collets  40  have a radially inwardly tapered surface  48  that abuts the correspondingly tapered inner surface  50  of the front cap  38 . The surfaces  48 ,  50  cooperate to translate axial movement of the collet actuator  46  into radial movement of the collets  40 . As the collet actuator  46  moves axially towards the front cap  38 , the collets are forced radially inward due to the interaction between the surfaces  48 ,  50 . In this manner, a tube  11  inserted into the bore of the gripping module  12  will be securely gripped by the collets  40 . In order to securely grasp a tube  11  received within the gripping module  12 , it is preferred to utilize four collets  40 , each collet  40  spanning an arc approaching 90 degrees. In this manner, the cylindrical clamping faces  41  of the collets  40  will contact the end of a tube  11  around substantially its entire circumference. The even contact between the collets  40  and the tubing  11  prevents damage to the tubing. The clamping faces  41  of the collets may be smooth or may be roughened to improve the grip that the collets  40  may exert upon the tubing  11 . 
     Tabs  42  of collets  40  are in this embodiment “T” shaped. However, it must be understood that any shape which would constrain the collets  40  to move axially with the collet actuator  46  may be used. Furthermore, tabs  42  may be formed integral with the body of the collets  40  or may be secured to the collets  40  by means of screw of bolt  43  as illustrated in FIG.  2 . 
     The collet actuator  46  is secured to return collar  52  by threads  54 . The return collar  52  has at its base end a radially outwardly extending annular ring  56 . Annular ring  56  has formed in its outer surface a groove  58  that contains a sealing mechanism such as an O-ring  60 . Throughout this description the term O-ring is to be construed broadly to encompass any and all suitable sealing mechanisms. The annular ring  56  limits the forward movement of the collet actuator  46  and collets  40  by abutting against a shoulder  62  formed within the bore of the gripping module body  32 . Rearward motion of the collet actuator  46  and collets  40  is limited by the end  36  of the gripping module body  32 . As can be seen in FIG. 2, the central portion of the collet actuator  46  has a diameter that is smaller than that portion into which the radial slots  44  are formed. A transition between the central portion of the collet actuator  46  and its end portion forms shoulder  64  which bears against the end  36  of the body  32  of the gripping module. 
     The body  32  of the gripping module has a port  66  formed through the side thereof and includes a connector  68  which allows a supply of pressurized fluid, preferably hydraulic fluids, to be connected to the port  66 . Port  66  communicates with the bore formed through the gripping module  12 , opening onto a shallow circumferential channel  70  formed in the body  32  of the gripping module. Channel  70  and return collar  52  define a small annular cavity  72  around the entire circumference of the return collar  52 . Immediately adjacent the circumferential channel  70  and on the side of the channel nearest the front cap  38 , a circumferential groove  74  is formed into the body  32  of the gripping module  12 . An O-ring or other seal  76  is disposed within the groove  74  so as to form a seal between the body  32  and return collar  52 . The circumferential channel  70  opens into a second annular cavity  78  formed between the shoulder  62  of the body  32  and the annular ring  56  of the return collar  52 . As can be appreciated, when the return collar  52  and collet actuator  76  are in a first, retracted position as illustrated in FIG. 2, the second annular cavity  78  is at its maximum size. When the return collar  52  and collet actuator  46  are in a second, extended position, annular ring  56  will approach or contact shoulder  62  and the volume of the annular cavity  78  will be minimized. 
     A small port  80  is formed through the wall of the return collar  52  and fluidically connects port  66  with a circumferential groove  82  formed around the hollow interior of the return collar  52 . 
     The expanding module  14  is best illustrated in FIGS. 3 and 5. The expanding module  14  comprises a body  84  having a bore formed therethrough that is sized to receive a piston means that actuates the collets  40  in the gripping module and which also actuates expansion tool  18 . Note that FIGS. 3 and 5 are illustrated without expansion tool  18 . The piston means of the expanding module  14  comprise a primary piston  86 , an actuator piston  88 , and an actuator nose  90 . Primary piston  86  is slidably received within a bore formed through actuator piston  88 . Actuator nose  90  is threaded into actuator piston  88  at threads  92 . Actuator piston  88  has a shaft  94 , which extends through an aperture  96  formed in the bottom of the body  84  of the expanding module. A circumferential groove  98  formed in the aperture  96  has an O-ring  100  disposed therein in order to created a seal between the shaft  94  and aperture  96 . The shaft  94  of the actuator piston  88  is sufficiently long to produce an axial or longitudinal stroke long enough to actuate the collets  40  so that they may grip a tube  11  received within the gripping module  12 . Interior to the aperture  96  the diameter of the bore formed in the body  84  of the expanding module expands to form a shoulder  102 . Shoulder  104  of the actuator piston  88  abuts shoulder  102  of the body  84 . The outer diameter of the actuator piston  88  is sized to create a close fitting relationship with the interior diameter of the bore formed through the body  84  of the expanding modular. A circumferential groove  106  is formed around the outer diameter of the actuator piston  88  and has an O-ring  108  disposed therein to form a seal between the body and the actuator piston. 
     Like the body  84  of the expanding module  14 , the actuator piston  88  also has a bore formed completely therethrough. The bore formed through the actuator piston  88  can be divided into a interior portion  110  which is disposed within the interior of the body  84  of the expanding module  14  and an exterior portion  112  which is disposed within the shaft  94  of the actuator piston  88  and which extends exterior to the body  84  of the expanding module. Between the interior and exterior portions  110 ,  112  of the bore in the actuator piston  88  exists a ridge  114 . Ridge  114  forms a shoulder  116  at the bottom of the interior portion  110  of the bore formed through the actuator piston  88  and a shoulder  118  at the bottom of the exterior portion of the bore formed through the actuator piston. Ridge  114  also defines an aperture  120  through which a shaft portion  122  of the primary piston  86  is received. The shaft portion  122  of the primary piston is thereby substantially disposed within the exterior portion  112  of the bore formed the actuator piston  88 . A circumferential groove  124  formed around the aperture  120  has disposed therein an O-ring  126 , which forms a seal between the shaft  122  of the primary piston and the aperture  120 . An interior portion or body  128  of the primary piston  86  is disposed within the interior portion  110  of the bore formed through the actuator piston  88  and within a coaxial bore formed through the actuator nose  90 . The diameter of the body  128  of the primary piston  86  is smaller than the interior diameter of the bore formed through the interior portion  110  of the actuator piston  88 . In order to center the body  128  of the primary piston within the actuator piston and to provide a seal therebetween, a wear ring  130  is received around the body  128  of the primary piston  86  immediately adjacent the shaft portion  122  of the piston. A circumferential groove  132  formed around the wear ring  130  has received therein an O-ring  134 , which forms a seal between the wear ring  130  and the interior diameter of that portion of the actuator piston  88 . Preferably, the wear ring  130  will be threaded onto the body  128  of the primary piston  86  such as by threads  136 . A shoulder  138  formed in the body  128  of the primary piston limits the movement of the wear ring  130  to the right as illustrated in FIG.  3 . Wear ring  130  has a shoulder  140 , which abuts shoulder  138  of the primary piston. It is also preferred to form a circumferential groove  142  in the body  128  of the primary piston immediately adjacent the shoulder  138 . This circumferential groove has an O-ring  144  disposed therein to create a seal between the wear ring  130  and the body  128  of the primary piston. 
     An annular cavity  146  is defined by the outer surface of the body  128  of the primary piston  86 , the interior surface of the interior portion  110  of the bore formed through the actuator piston  88 , the wear ring  130 , and the actuator nose  90 . As can be appreciated, where the primary piston is in a first, retracted position as illustrated in FIG. 3, the annular cavity  146  is at its maximum size. Where the primary piston  86  has been actuated and moved to a second, extended position, the wear ring  130  will approach or contact the actuator nose  90 , thereby minimizing the volume of the annular cavity  146 . A port  148  is formed through the actuator nose  90  in order to provide a fluidic connection between the annular cavity  146  and a shallow channel  150  formed around the exterior circumference of the actuator nose  90 . The channel  150  in the actuator nose  90  is bounded on either side by circumferential groove  152  having disposed therein O-rings  154 . 
     In order to operate the end former  10  of the present invention, it is necessary couple the gripping module  12  to either an expanding module  14  or a reducing module  16 . FIGS. 5 and 6 illustrate the gripping module  12  as it coupled to an expanding module  14  and a reducing module  16 , respectively. As can be appreciated from the figures, the bodies of the expanding and reducing modules  14 ,  16  are substantially identical and therefore, mate with the body of the gripping module  12  in substantially the same way. With this mind, and for the purposes of brevity, only the connection between an expanding module  14  and the gripping module  12  will be described in detail. 
     Referring to FIG. 5, it can be seen that the body  32  of gripping module  12  has a cylindrical projection  156  extending from its base end. A corresponding cylindrical cavity  158  is formed into an end face of the body  84  of the expanding module  14  and receives the cylindrical projection  156  of the clamping modular  12  therein when the gripping module  12  and expanding module  14  are connected. It is preferred to provide a seal such as an O-ring between the mating faces of the expanding module and gripping module. Bolts  160  pass through bores  162  formed through the solid body  84  of the expanding module and are threaded into blind holes  164  formed in the body  32  of the gripping module  12 , thereby securely clamping the gripping and clamping modules together. 
     Operation of the endformer  10  when configured to expand tubing  11  will be described in conjunction with FIG.  5 . In operation, pressurized fluid is introduced into the expanding module  14  via fitting  69 . This pressurized fluid causes the piston means disposed within the expanding module  14  to actuate the collet means of the gripping module  12  to grasp a tube  11  that has been inserted into the gripping module. FIG. 5 does not illustrate the expansion tool  18  that is typically used with the expansion module  14 . Examples of the expansion tool  18  are illustrated in FIGS. 1 and 7. The pressurized fluid being introduced into fitting  69  will also cause the piston means to actuate the expansion tool  18  so as to expand the diameter of the tubing  11  in a desired manner. Once the desired diameter has been formed into the end of tubing  11 , the flow of pressurized fluid into fitting  69  is cut off and pressurized fluid is then introduced into fitting  68  of the gripping module  12 . 
     Pressurized fluid introduced into fitting  69  of the gripping module  12  causes the piston means within the expanding module  14  to be retracted to its initial position, thereby retracting the expansion tool  18  and releasing the collet means grip upon the tubing  11 . 
     Specifically, in operation a tube or tubing  11  is inserted into the bore formed through the gripping module  12  as illustrated in FIGS. 7 a  and  7   b . At this point, a pressurized fluid is introduced through fitting or connector  69  into port  85  that is formed through the wall of the body  84  of the expansion module  14 . Port  85  is in fluidic communication with a shallow channel  103  formed on the shoulder  104  of the actuator piston  88 . In this manner, the pressurized fluid acts to force the actuator piston  88  away from shoulder  102  and toward the gripping module  12 . As the actuator piston  88  moves toward the gripping module, the actuator nose  90  secured to the actuator piston  88  contacts the collet actuator  46  and forces it to move axially in the direction of the front cap  38  of the gripping module  12 . As described above, the axial motion of the collet actuator  46  is also experienced by the collets  40 , and by the interaction between tapered surfaces  48 ,  50  on the collets and front cap, the axial motion is translated into inward radial motion of the collets  40 . As the actuator piston  88  continues to move toward the gripping module  12 , the collets  40  are forced radially inward into gripping contact with the tube  11  received within the gripping module  12 . 
     A small port  87  is formed through the actuator piston  88  and fluidically connects the shallow channel  103  with an annular cavity defined by the wear ring  130  and the interior portion  110  of the bore formed through the actuator piston  88 . Pressurized fluid entering the annular cavity formed between the actuator piston  88  and the wear ring  130  forces the primary piston  86  to move axially toward the gripping module  12 . The relative sizes of the ports  85 ,  87  and channel  103  help to insure that the actuator piston  88  will actuate the collet means to firming grasp the tubing  11  before the primary piston  86  can bring the expansion tool  18  into contact with the tubing  11 . Ideally the primary piston  86  will not move with respect to the actuator piston  88  until such time as the actuator piston has fully actuated the collet means to grasp the tubing  11 . However, the stroke of the primary piston  86  with respect to the actuator piston  88  may begin prior to the full actuation of the collet means. 
     The stroke of the actuator piston  88  is limited by the amount of axial travel necessary to bring the collets into firm gripping contact with the tube  11 , or by the limited range of motion of the collet actuator  46  within the body  32  of the gripping module  12 . Full extension of the primary pistons  86  allows the expansion tool  18  to modify the tubing  11  clamped within the collet means of the gripping module  12  as illustrated in FIG.  7 . 
     Once full extension of the primary piston  86  has been achieved, the supply of pressurized fluid through fitting or connector  69  is cut off and a pressurized fluid is introduced into connector  68 . The pressurized fluid moving into the endformer  10  through connecter  68  into ports  66  causes the primary and actuator pistons  86  and  88  to retract, thereby forcing the fluid that actuated these pistons out of the endformer  10  through port  85  and connector  69 . Pressurized fluid from port  66  flows through circumferential channel  70  and into annular cavity  72 . The presence of pressurized fluid in the annular cavity  72  causes the return collar  52  to move to its retracted position adjacent the expansion module  14 . Simultaneously, pressurized fluid passes through port  80  and into circumferential groove  82 . Actuator nose  90  has a shallow channel  150  formed in its surface opposite the circumferential groove  82  formed in the interior of the return collar  52 . Channel  150  is wide enough such that there is fluid communication between the groove  82  and channel  150  throughout the entire retracting stroke of the piston means. Pressurized fluid passes through the port  148  in the actuator nose  90  and enters the cavity  164  where the pressurized fluid forces the wear ring  130  into the bore formed through the actuator piston  88  until the wear ring  130  abuts an interior shoulder  166  of the actuator piston  88 . 
     Where the stroke of actuator piston  88  is ultimately limited by the travel of the collet actuator  46 , the stroke of the primary piston  86  is limited by interior shoulder  166  and a stroke adjustment means coupled to the end of the primary piston  86 . The stroke adjustment means is comprised of an adjustment knob  168  having a cylindrical bore formed there through. Near the tip  170  of the adjustment knob  168  the bore formed through the adjustment knob is sized to slidably receive therein the shaft of the primary piston  86 . The adjustment knob  168  is retained on the shaft of the primary piston  86  by an adjustment retainer  172  that is threaded onto the end of the shaft of the primary piston  86  at threads  174 . While the shaft of the primary piston  86  slides freely through the bore of the adjustment knob  168 , the adjustment knob itself is retained within the exterior portion  112  of the bore formed through the actuator piston  88  by threads  176 . In general, the adjustment knob  168  may be threaded deeper into the exterior portion of the bore formed through the actuator piston  88  in order to provide a longer stroke for the primary piston  86 , and may be backed out of the exterior portion of the bore through the actuator piston  88  in order to shorten the stroke of the primary piston  86 . In operation, as the primary piston  86  moves from its retracted position to its extended position, the adjustment retainer  172  will abut a shoulder  171  formed within the cylindrical bore of the adjustment knob  168 . Shoulder  171  prevents the primary piston  86  from being extended any further. In order to prevent the inadvertent modification of the stroke length of the primary piston  86 , a set screw  178  is passed through a bore formed through the shaft of the actuator piston such that the set screw will contact the adjust knob  168 . 
     Two version of an expansion tool  18  are illustrated in FIGS. 7 a  and  7   b . The expansion tools  18  illustrated in FIGS. 7 a  and  7   b  are substantially identical with only the dimensions being variable. As can be appreciated, by changing the relative sizes of the piston extension  20 , the forming insert  22 , and the sizing mandrel  24 , variously sized tubes  11  may be modified using a single modular end former  10 . The installation of the expansion tool  18  is straight forward with the piston extension  20  being threadedly received within a threaded bore  180  formed in the end of the primary piston  86 . The piston extension  20  is long enough to extend past the end of the actuator nose and into the cylindrical bore of the collet actuator  46 . With the front cap  38  of the gripping module  12  removed and the collets  40  moved radially outward, a forming insert  22  may be inserted into the cylindrical bore of the collet actuator  46 . The forming insert  22  is sized to create a close sliding fit with the bore of the collet actuator. The forming insert  22  is retained within the collet actuator  46  by the collets  40  which are slid radially inward to partially occlude the end of the bore formed through the collet actuator  46 . A stepped bore  23  is formed entirely through the forming insert  22 . Sizing mandrel  24  is inserted into the stepped bore  23  and threaded into threaded bore  21  formed in the end of the piston extension  20 . The base of the sizing mandrel  24  abuts shoulder  23 A within stepped bore  23 . An additional shoulder  23   b  is formed within the stepped bore  23  to allow for expansion of the material of the tube wall. Shoulder  23   b  also aids in pushing a modified tube  11  off the sizing mandrel  24  as the primary piston  86  retracts. As can be seen from a comparison of FIG. 7A and 7B, it may also be necessary to utilized collets  40  of slightly different dimensions in order to more securely grasp variously sized tubes  11 . For example, in FIG. 7A the expansion tool  18  is arranged to expand a tube  11  that is relatively small. Therefore, the collets  40  illustrated in FIG. 7A are correspondingly larger so as to be able to grasp the smaller tube  11 . In FIG. 7B, the converse is true; a relatively large tube  11  is to be grasped, thereby requiring correspondingly smaller collets  40 . 
     It is important to note that by utilizing forming inserts  22  having varying inner diameters, and by matching these forming inserts  22  with appropriately sized sizing mandrels  24 , the end former  10  can expand the ends of virtually any sized tube  11  within a given range. Use of the forming inserts  22  also helps to control the outer diameter of the tubing  11  being modified and ensures that the tube end will be straight once modified. Furthermore, the length of tubing  11  that may be expanded by an expanding tool  18  is continuously variable over a given range of preferably zero to 1 inch, though it is contemplated that a larger piston stroke may increase this range. Where desired, the geometry of the end former  10  may be modified so as to provide a larger or smaller range. 
     Where the modular end former  10  is to be utilized to either reduce the diameter or flare the end of a tube, the gripping module  12  will be connected to the reducing module  16  in the same manner as the expanding module  14  was secured to the gripping module  12 . Referring now to FIG. 4, a reducing module  16  according to the present invention is illustrated. It is to be understood that the principle of operation and in many cases the structure of the reducing module  16  are identical to those of the expanding module  14 . The differences between the expanding module  14  and the reducing module  16  stem from the nature of the reducing tool  26  that is used to reduce the diameter of a tube  11  and a flaring tool  25  used to flare the ends of a tube  11 . 
     The reducing module  16  comprises a body  200  that is substantially identical to the body  32  of the gripping module  12 . Similarly, the piston means of the reducing module  16  comprises an actuator piston  202  and an actuator nose  204  which are also substantially identical to the actuator piston  88  and actuator nose  90  of the expanding module  14 . The differences between the expanding and reducing modules is therefore limited to differences in the primary piston and the adjusting means. Therefore, only the adjustment means and the primary piston  206  of the reducing module  16  will be discussed in detail. 
     The primary piston  206  of the reducing module  16  is slidably received within a bore formed by the actuator piston  202  and actuator nose  204 . The primary piston  206  is itself cylindrical and has a longitudinal stepped bore formed there through. A forming die  28  or flaring tool  25  may be threaded into the stepped bore of the primary piston  206  by threads  212  as illustrated in FIGS. 8A and 8B. A circumferential groove  214  having an O-ring  216  disposed therein is formed around the interior of the actuator nose  204  and forms a seal between the actuator nose and primary piston. A wear ring  218  is threaded onto a base end of the primary piston  206  by threads  220 . The diameter of the primary piston  206  at threads  220  is slightly smaller than the remainder of the primary piston and forms a shoulder  222  against which a shoulder  224  of wear ring  218  abuts. A circumferential groove  226  formed around the exterior of the primary piston  206  adjacent shoulder  222  has an O-ring  228  disposed there which forms a seal between the wear ring and the primary piston. Similarly, a circumferential groove  230  formed around the exterior of the wear ring  218  has an O-ring  232  received therein, which forms a seal between the wear ring and the interior of the actuator piston  202 . 
     The primary piston  206  reciprocates between a first retracted position in which the base of the primary piston  206  and wear ring  218  abut against a shoulder  234  of the actuator piston  202 , and a second extended position in which the wear ring  218  abuts against the actuator nose  204 . The length of the stroke of the primary piston  206  may be adjusted using the adjustment bolt  208  which is received through the body  200  of the reducing module  16  through the bore of the actuator piston  202  and into the bore formed through the primary piston  206 . The adjustment bolt  208  has a shoulder  236  formed there around which abuts against a corresponding shoulder  238  formed the base of the primary piston  206 . In operation, the adjustment bolt  208  does not move with respect to the actuator piston  202 . This is accomplished by means of collar  240 , which threadedly engages the interior of the actuator piston  202  at  242 . That portion of the bore formed through the actuator piston  202 , which extends exterior to the body  200  of the reducing module  16 , is threaded over substantially its entire length. The end of the adjustment bolt  208  is formed in a manner, which would allow standard tools, such as a wrench, to be used to rotate the adjustment bolt  208 . The retaining collar  210  has a bore formed therethrough and is received over the end of the adjustment bolt  208  and threaded into the bore of the actuator piston  202  by threads  244 . A setscrew  246  prevents the retainer collar  210  from backing out of the bore of the actuator piston  202 . Similarly, a setscrew  248  formed through the retainer collar  210  impinges upon the adjust bolt  202  to prevent the inadvertent movement of the adjustment bolt  208  with regard to the actuator piston  202 . A groove  250  formed around the interior of the bore of the actuator piston  202  has retained therein an O-ring  252 , which forms a seal between the actuator piston  202  and the adjustment bolt  208 . A circumferential groove  254  formed around the interior bore of the primary piston  206  also has an O-ring  256  received therein which forms a seal between the interior of primary piston  206  and the adjustment bolt  208 . 
     A threaded bore  258  formed in the end of the adjustment bolt  208  is constructed and arranged to receive the threaded shaft  31  of the removal shoulder  30  therein. 
     Where the modular end former  10  is configured with the reducing module  16  bolted to the gripping module  12  by bolts  160 , and has a removal shoulder  30  threadedly attached to the adjustment bolt  208  and a forming die  28  threadedly attached to the primary piston  202 , the endformer  10  may be utilized to reduce the other diameter of a tube  11  as illustrated in FIG.  8 A. In FIG. 8A, the piston means of the end former  10  are in their retracted position, and tubing  11  has been inserted into the gripping module  12 . At this stage, pressurized fluid introduced into connector  69  actuates the piston means of the reducing module  16  which in turn actuates the collet means of the gripping module  12  to firming grasp the tubing  11 . Simultaneously, the primary piston  86  will move from its retracted position to its fully extended position. It is noted that the removal shoulder  30  that is secured to the adjustment bolt  208  remains stationary with regard to the actuator piston  202 . As the primary piston  206  moves to its fully extended position, an inwardly tapered surface  29  of forming die  28  forces the walls of the tube  11  inwardly, thereby reducing the outer diameter of tubing  11 . Once the primary piston  206  has reached its fully extended position, the supply of pressurized fluid to connection  69  is cut off and pressurized fluid is introduced into connecter  68 , thereby causing the piston means of the reducing module  16  to retract to its first position. The pressurized fluid causes the return collar  52  of the gripping module  12  to retract the collet actuator  46  which in turn causes the collets  40  to release their grip on the tubing  11 . Simultaneously, the primary piston  206  of the reducing module  16  retracts until the end of tubing  11  contacts the removal shoulder  30 . As the retracting primary piston  206  moves the forming die  28  past the removal shoulder  30 , the removal shoulder  30  effectively pushes the tubing  11  out of the forming die  28  so that the tubing  11  may be removed from the endformer  10 . 
     Where the endformer  10  is configured for use in a flaring operation as illustrated in FIG. 8 b , the forming die  28  and removal shoulder  30  are omitted in favor of a flaring tool  25  that is threaded into threads  212  in the primary piston  206 . It can be appreciated from FIG. 8 b  that the forward stroke of the primary piston  206  will cause the flaring tool  25  to address the end of a tube  11  received within and firmly gripped by the collet means of the gripping module  12 . The force exerted upon the end a tube  11  by the flaring tool  25  causes the tip of a tube  11  to be flared or belled out in a manner well known in the art. Retraction of the piston means of the reducing module  16  breaks the contact between the flaring tool  25  and the tube  11 . Pressurized fluid flowing through connector  68  will cause return collar  52  to actuate the retraction of collets  40 , thereby releasing the now-flared tube  11  from the gripping module  12 . 
     In the same manner as described above in conjunction with the expansion tool  18 , it can be appreciated that by varying the dimensions of the forming die  28 , the removal shoulder  30 , and the flaring tool  25 , many different tubes  11  of varying sizes may be modified using a single modular end former  10 . 
     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.