Abstract:
A tube bending machine for bending a length of a tubular workpiece and an associated tube feeder assembly are disclosed. The tube feeder assembly has a carriage assembly slidably mounted along a rail. A clamp assembly is reversibly mounted to and carried by the carriage assembly. The clamp assembly is adapted to be releasably secured to the workpiece. The clamp assembly and carriage assembly are configurable to align the workpiece central axis along the rail, whereby sliding of the carriage assembly with the workpiece mounted in the clamp assembly carries the workpiece along the rail.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/904,023, filed on Nov. 14, 2014, which is incorporated herein in its entirety by reference. 
     
    
     STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    1. Field of Invention 
         [0004]    The invention relates to tube bending machines, and particularly, to a reversible clamp assembly for a tube bending machine, and a tube bending machine incorporating a reversible assembly. 
         [0005]    2. Description of the Related Art 
         [0006]    Numerous buildings, construction sites, manufacturing plants, machine shops, and the like use bent tubes, pipes, bars, rods, or the like (hereinafter, collectively, “tubes”) to produce a variety of items such as hand rails, scaffolding, automotive parts, or other fabricated metal products. In the manufacture and forming of tubes, several types of tube bending machines are known which are useful to permanently form tubes to a desired shape. In various tube bending machines, a tube is clamped into place in a clamping block, and a portion of the tube to be bent is positioned within a working area of a forming die. Thereafter, mechanical force is applied to force the portion of the tube to be bent to conform to the forming die. The source of such mechanical force varies depending on the type of tube bending machine, however, several types of tube bending machines rely on human power, pneumatics, hydraulics, electric servomotors, and the like. 
         [0007]    One type of tube bending machine is the rotary draw bender. This type of machine uses an annular forming die which is mounted in a coaxial configuration to a rotatable spindle. The forming die has a concave groove extending about at least a portion of a perimeter edge thereof. A fastener is provided at a leading end of the groove to fasten a first end of a tube adjacent the leading end of the groove. A pressure die is provided to maintain the tube adjacent the bending die. The spindle and subordinate forming die are then rotated about their co-axis, whereupon the tube is “drawn” along the groove of the forming die, thereby bending the tube in conformity with the groove. 
         [0008]    In several rotary draw bender designs, a clamping block is provided which includes a tubular clamp or chuck adapted to be releasably secured to a second end of the tube, opposite the above-discussed first end. The clamping block is slidably mounted along a support rail which extends from an input end of an interface of the forming die and the pressure die. Thus, as the forming die is rotated and the tube is drawn along the groove of the forming die, the clamping block slides along the support rail in order to “feed” additional tube through the interface of the forming die and the counter die, while simultaneously maintaining the second end of the tube in alignment with a feeding direction of the rotary draw bender. 
         [0009]    In certain designs, the clamping block may allow indexed rotation of the tube about the feeding direction of the rotary draw bender, thereby allowing multiple bends to be performed in multiple directions along the length of the tube, wherein the angle of extension of each bend in relation to adjacent bends is controllable via the indexed rotation of the tube within the clamping block. This type of rotary draw bender is often desirable when the need exists to perform multiple bends in multiple directions at precise locations and at precise angles along the length of a tube. However, this type of bending operation presents a number of problems. For instance, use of such a tube bending machine to effect two bends in a single piece of tubing typically involves starting with a straight tubular work piece, forming a first bend proximate a first end of the tube, adjusting the position of the clamping block toward the forming die to allow the bent portion of the tube to move unsupported beyond the forming die and, if necessary, adjusting the rotation of the work piece in relation to the clamping block, and then forming a subsequent bend in the tube. These operations may be repeated to form multiple bends in sequence toward the second end of the tube. However, once the first bend in the tube proximate the first end of the tube is formed, the operation of forming subsequent bends in the tube toward the second end of the tube can result in drastic swinging of the unsupported first end of the tube, due to the geometry of the previous bend(s) and the extension of the first end of the tube beyond the forming die. If the first end of the tube is not properly supported, this can result in warping, deformation, or other inaccuracies in the geometry of the finished tube product. 
         [0010]    Furthermore, in the above-discussed rotary tube bender design, in order for the above-discussed indexed rotation of the tube in relation to the clamping block to remain consistent throughout all bending operations performed along the length of the tube, the second end of the tube must remain secured within the chuck of the clamping block throughout each stage of the bending process. In most rotary tube bender designs, the clamping block is incapable of feeding at least a portion of the tube nearest the second end through the interface of the forming die and the counter die. Thus, in previous prior art rotary tube bender designs, it is difficult to perform a bend at or near the second end of the tube without also disconnecting the second end of the tube from the clamping block, thereby sacrificing stability of the tube within the rotary tube bender and potentially allowing inconsistency of measurement of rotation of the tube about the feeding direction during multiple bending processes. 
         [0011]    In light of the above, there is a need in the art for a tube bending machine that allows a user to access both ends of a tubular work piece for bending without sacrificing stability of the tube within the rotary tube bender and while limiting inconsistency of measurement of rotation of the tube about the feeding direction during the bending process. 
       BRIEF SUMMARY OF THE INVENTION 
       [0012]    The present general inventive concept, in various example embodiments, provides a tube feeder assembly configured to allow feeding of a tubular workpiece along a central axis of the workpiece from either of opposite ends of the workpiece. In various embodiments, the tube feeder assembly may be incorporated into a tooling machine for tooling a tubular workpiece, such as for example a tube bending machine for bending a length of a tubular workpiece. For example, in one embodiment, the tube bending machine may comprise a forming die defining a curved concave groove, and a fastener proximate a first end of the curved concave groove, the fastener being configured to maintain at least a portion of the workpiece adjacent a first end of the curved concave groove. A counter die defining a linear concave groove may be positionable adjacent the curved concave groove to maintain at least a portion of the workpiece along the curved concave groove. A power source may be configured for driving rotation of the forming die along the curved concave groove in relation to the counter die, whereby rotation of the forming die is adapted to conform at least a portion of the workpiece along the curved concave groove. 
         [0013]    In various example embodiments of the present general inventive concept, the tube feeder assembly may comprise a linear member, such as for example a rail, extendable from proximate an interface of the linear and curved concave grooves. A carriage assembly may be mounted to and moveable along the linear member, and a clamp assembly may be reversibly mounted to the carriage assembly. The clamp assembly may be configured to be releasably secured to the workpiece and to carry the workpiece along the linear member with the carriage assembly. Thus, when the linear member is extended from proximate the interface of the linear and curved concave grooves, the clamp assembly and carriage assembly may be configurable to cooperate to carry the workpiece toward the interface along the linear member. 
         [0014]    In various example embodiments, the clamp assembly may further comprise a clamping block releasably securable along a central portion of the workpiece. The clamping block may be releasably mountable to the carriage assembly with a first end of the workpiece extending toward a first end of the linear member. The clamping block may be alternately releasably mountable to the carriage assembly with an opposite second end of the workpiece extending toward the first end of the linear member. In some embodiments, the clamping block may comprise upper and lower portions, each of the upper and lower portions defining a substantially semi-cylindrical recess, the recesses being opposable to cooperatively surround and frictionally engage the workpiece. The clamping block may further comprise a plurality of fasteners configured to bias the upper and lower portions toward one another. The clamping block may yet further comprise a plurality of through holes disposed in a configuration symmetrical about an axis perpendicular to an interface of the upper and lower portions, each of the through holes being adapted to receive a fastener therein to mount the clamping block to the carriage assembly. In some embodiments, the plurality of through holes may be disposed along the lower portion. 
         [0015]    In certain example embodiments, the carriage assembly may comprise a rotatable disc. The clamping block may be releasably mountable to the disc to align a central axis of a workpiece releasably secured to the clamping block with a central axis of the disc. The carriage assembly may further comprise a base member slidably mounted to the linear member and a planar member extending perpendicular to the linear member. The rotatable disc may be rotatably secured along the planar member. In some embodiments, the planar member may be mounted for slidable adjustment toward and away from the base member. In some embodiments, the planar member may define a circular through opening and a circumferential lip extending about a perimeter of the through opening, the disc being received and retained within the through opening adjacent the lip. 
         [0016]    In various embodiments, the disc may define a first cutout extending from a central axis of the disc to an upper perimeter edge of the disc. The planar member may define a second cutout extending from the through opening to a perimeter edge of the planar member. The disc may be rotatable to align the first and second cutouts to allow receipt therethrough of a portion of a workpiece releasably secured to the clamping block. In some embodiments, the disc may define angular measuring indicia about a perimeter surface thereof. In some embodiments, the base member may be pivotable in relation to the linear member. 
         [0017]    Additional features, aspects, and advantages of the present general inventive concept will be set forth in part in the description which follows, and, in part, will be apparent from the description, or may be learned by practice of the present general inventive concept. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0018]    The following example embodiments are representative of example techniques and structures designed to carry out the objects of the present general inventive concept, but the present general inventive concept is not limited to these example embodiments. In the accompanying drawings and illustrations, the sizes and relative sizes, shapes, and qualities of lines, entities, and regions may be exaggerated for clarity. A wide variety of additional embodiments will be more readily understood and appreciated through the following detailed description of the example embodiments, with reference to the accompanying drawings in which: 
           [0019]      FIG. 1  is a perspective view of one embodiment of a tube bending machine with a reversible clamp assembly constructed in accordance with several features of the present general inventive concept; 
           [0020]      FIG. 2  is another perspective view of the tube bending machine of  FIG. 1 ; 
           [0021]      FIG. 3  is a partial perspective view of the tube bending machine of  FIG. 1 , showing the forming die and pressure die portions in greater detail; 
           [0022]      FIG. 4  is another partial perspective view of the tube bending machine of  FIG. 1 ; 
           [0023]      FIG. 5  is a perspective view of one embodiment of a carriage assembly for a tube bending machine incorporating a reversible clamp assembly constructed in accordance with several features of the present general inventive concept; 
           [0024]      FIG. 6  is an exploded view of a portion of the carriage assembly of  FIG. 5 ; and 
           [0025]      FIG. 7  is an exploded view of another portion of the carriage assembly of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    Reference will now be made to the example embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings and illustrations. The example embodiments are described herein in order to explain the present general inventive concept by referring to the figures. The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the structures and fabrication techniques described herein. Accordingly, various changes, modification, and equivalents of the structures and fabrication techniques described herein will be suggested to those of ordinary skill in the art. The progression of fabrication operations described are merely examples, however, and the sequence type of operations is not limited to that set forth herein and may be changed as is known in the art, with the exception of operations necessarily occurring in a certain order. Also, description of well-known functions and constructions may be omitted for increased clarity and conciseness. 
         [0027]    Note that spatially relative terms, such as “up,” “down,” “right,” “left,” “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over or rotated, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated  90  degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
         [0028]    According to various examples of the present general inventive concept, a tube bending machine is provided which incorporates a reversible tube clamp assembly. The tube bending machine is configured to receive a portion of a tube and to apply mechanical force to the received portion of tube to conform the received portion of the tube to a bent shape. The reversible clamp assembly is securable to a carriage assembly configured to feed a length of tube to be bent into the tube bending machine, and is repositionable between a forward-facing orientation and a rearward-facing orientation, such that a user may alternately position and secure first and second ends of a tube received within the reversible clamp assembly along a forming die for bending by the tube bending machine without the need to disconnect the tube from the clamp assembly. As will be further discussed hereinbelow, the clamp assembly is securable to the carriage assembly in both forward-facing and rearward-facing orientations in a known orientation in relation to the carriage assembly. Thus, the carriage assembly is capable of maintaining accurate rotational orientation of the tube in relation to the forming die in both forward-facing and rearward-facing orientations, thereby allowing a user to form accurate and precise bends along both of opposite ends of the tube. Thereafter, the reversible clamp assembly is removable from the tube absent the need to slide the tube along the carriage assembly. 
         [0029]      FIGS. 1-4  illustrate one embodiment of a tube bending machine  10  constructed in accordance with several features of the present general inventive concept. In the embodiment of  FIGS. 1-4 , the tube bending machine, or “bender,” is of the type of bending machine commonly referred to as a “rotary draw bender” and includes an annular forming die  12  which is mounted in a coaxial configuration to a rotatable spindle  14 . The forming die  12  has a perimeter defining a generally semi-circular outer rim portion  16  and a central axis  18  extending from the center of the circle defined by the outer rim portion  16 , perpendicular to the outer rim portion  16 . A concave forming groove  20  extends along the outer rim portion  16  and defines a leading end  24  and an opposite trailing end  26 . The forming groove  20  has a generally semi-circular cross-section which is shaped to at least partially conform to a cross-section of a tube  22  to be bent. 
         [0030]    As is best shown in  FIGS. 3 and 4 , a releasable fastener  28  is provided proximate the leading end  24  of the groove  20  and is configured to secure a portion of the tube  22  adjacent the leading end  24  of the groove  20 . In the illustrated embodiment, the forming die  12  defines a relatively flat edge portion  30  extending tangentially outwardly from the leading end  24  of the groove  20 . The fastener  28  is mounted adjacent the flat edge portion  30  of the forming die  12  and includes a hook-shaped strap portion  32  which is adapted to encircle the tube  22  to secure the tube  22  against the leading end  24  of the groove  20 . The strap portion  32  is securable at each of opposite ends to respective upper and lower surfaces  34 ,  36  of the forming die  12 . Thus, the strap portion  32  of the fastener  28  and the leading end  24  of the groove  20  cooperate to define a substantially tubular-shaped inward-facing interface  37  which is configured to closely conform to and engage a portion of the tube  22  to maintain the encircled portion of the tube  22  against the leading end  24  of the groove  20 . For ease of reference hereinbelow, it will be recognized that the fastener interface  37  defines a central axis  38  which extends in a substantially straight line outward from, and tangential to, the leading end  24  of the groove  20 . 
         [0031]    As shown in  FIGS. 2 and 4 , the spindle  14  is mounted for rotational movement about a central axis thereof in relation to a base structure between a first position ( FIG. 2 ) and a second position ( FIG. 4 ). For example, in the illustrated embodiment, the spindle  14  is rotatably mounted to a bench support  40  via suitable bearings and connections of the type known to one of ordinary skill in the art, such that the coaxis of the spindle  14  and the forming die  12  extend substantially vertically. A first power source  50  is provided for effecting controlled rotation of the spindle  14  and subordinate forming die  12  between the first and second positions. For example, in the illustrated embodiment, a cantilevered moment arm  42  is provided, with a first end  44  of the moment arm  42  fixed in relation to the spindle  14  and extending substantially horizontally outwardly therefrom, perpendicular to the coaxis of the spindle  14  and the forming die  12 . A second end  46  of the moment arm  42  is rotatably secured to a first end  52  of a double-acting piston/cylinder device  54 . An opposite second end  56  of the double-acting piston/cylinder device  54  is rotatably mounted to a portion of the bench support  40 , such that extension of the piston/cylinder device  54  urges rotation of the spindle  14  and forming die  12  from the first position toward the second position, and retraction of the piston/cylinder device  54  urges rotation of the spindle  14  and forming die  12  from the second position toward the first position. The piston/cylinder device  54  may be powered by compressed fluid from a suitable reservoir (not shown), the start, stop, duration and direction of flow of which may be controlled by a conventional controller. Whereas the depicted first power source  50  is of the piston/cylinder type, it will be recognized that other types of power sources may be employed without departing from the spirit and scope of the present invention. 
         [0032]    Referring to  FIGS. 1 and 3 , a pressure die  58  is provided having a generally rectangular peripheral shape and defining a substantially straight, elongated, concave groove  60  at an outer end  62  thereof. The groove  60  of the pressure die  58  is of similar cross-sectional size and shape to the groove  20  of the forming die  12 , and the pressure die  58  is oriented such that the groove  60  of the pressure die  58  faces the groove  20  of the forming die  12 , with the elongated dimension of the pressure die groove  60  extending along a plane defined by the curved groove  20  of the forming die  12 . The pressure die  58  is mounted for linear movement toward and away from the forming die  12 , perpendicular to the coaxis of the forming die  12  and the spindle  14 , between a first position ( FIG. 3 ), in which the groove  60  of the pressure die  58  is positioned adjacent the groove  20  of the forming die  12 , and a second position ( FIG. 1 ), in which the pressure die  58  is moved away from the forming die  12  along the bench support  40 . 
         [0033]    In various embodiments, a second power source  64  is provided for effecting controlled linear movement of the pressure die  58  between the first and second positions. For example, in the illustrated embodiment, the pressure die  58  is mounted to a rod  66 , which is in turn mounted for slidable movement along a long dimension of the rod  66  in relation to the bench support  40 . A cantilevered lever arm  68  is provided in mechanical engagement with the rod  66  via a plurality of mechanical linkages  72 , such that rotation of the lever arm  68  away from the forming die  12  results in movement of the rod  66  and pressure die  58  toward the forming die  12 , thus toward the first position of the pressure die  58 , while rotation of the lever arm  68  toward the forming die  12  results in movement of the rod  66  and pressure die  58  away from the forming die  12 , thus toward the second position of the pressure die  58 . In certain embodiments, the arrangement of the linkages  72  is such that, when the lever arm  68  is rotated sufficiently away from the forming die  12  as to bring the pressure die  58  to the first position, the linkages  72  over-rotate to lock the pressure die  58  in the first position, thereby limiting withdrawal of the pressure die  58  from the first position absent deliberate rotation of the lever arm  68  toward the forming die  12 . In other embodiments, the pressure die  58  is secured via suitable linkages to a first end of a double-acting piston/cylinder device, similar to the piston/cylinder device discussed above. An opposite second end of the double-acting piston/cylinder device is mounted to a portion of the bench support  40 , such that extension of the piston/cylinder device urges sliding movement of the pressure die  58  toward the first position, and retraction of the piston/cylinder device urges sliding movement of the pressure die  58  toward the second position. Those of skill in the art will recognize other devices and configurations which may be used to accomplish the second power source  64  without departing from the spirit and scope of the present general inventive concept. 
         [0034]    Referring to  FIG. 3 , with the pressure die  58  in its first position, the groove  60  of the pressure die  58  is situated adjacent the groove  20  of the forming die  12 . Thus, the pair of grooves  60 ,  20  cooperate to form a substantially tubular intake interface  74  which is sized and shaped to receive a portion of a tube  22  therein and to maintain the received portion of the tube adjacent the portion of the forming die groove  20  opposite the pressure die  58 . When both the forming die  12  and the pressure die  58  are positioned in their respective first positions, the fastener  28  is positioned adjacent the pressure die  58 , with the central axis  38  of the fastener interface  37  aligned coaxially with a central axis  76  of the intake interface  74 . In this configuration, the pressure die  58  may be withdrawn from the forming die  12  toward its second position, and the fastener  28  may be loosened and/or disconnected from the forming die  12 , thereby allowing a straight portion of a tube  22  to be positioned through the intake interface  74  and the fastener interface  37  such that the tube  22  extends along the leading end  24  of the forming die groove  20 . Thereafter, the fastener  28  may be tightened and/or secured to the forming die  12 , thereby binding the tube  22  against the leading end  24  of the forming die groove  20 . The pressure die  58  may be advanced to its first position, and the forming die  12  may be rotated toward its second position, whereupon the portion of the tube  22  trailing the fastener interface  37  is “drawn” along the groove  20  of the forming die  12 . With the pressure die  58  in its first position, the pressure die  58  maintains the portion of tube  22  within the intake interface  74  against the groove  20  of the forming die  12 , thereby forcing the tube  22  to bend in conformity with the groove  20  of the forming die  12 . At the same time, the pressure die  58  and associated groove  60  are configured such that the tube  22  may slide along the length of the groove  60 . Thus, as the forming die  12  is rotated toward its second position, additional tube  22  may be drawn through the intake interface  74  and “fed” along the length of the groove  20  of the forming die  12 . Thus, it will be recognized that the central axis  76  of the intake interface  74  defines a feeding direction of the bender  10  extending along the central axis  76 , toward the fastener  28  when the forming die  12  is in its first position. 
         [0035]    In various embodiments, the bender  10  includes a tube feeding and support system which is adapted to support a length of tube  22  to be bent along the feeding direction of the bender  10 , coaxial with the central axis  76  of the intake interface  74 , and to allow controlled feeding of the tube through the intake interface  74  and along the groove  20  of the forming die  12  during the above-discussed bending process. For example, in the illustrated embodiment, a track  78  is provided at a location slightly below the intake interface  74  of the bender  10  and extending generally horizontally outwardly, parallel to, and opposite of, the feeding direction of the bender  10 . More specifically, the track  78  includes a first end  80  which is slidably mounted within a slot  82  defined along the bench support  40 . The slot  82  extends generally horizontally beneath the intake interface  74 , perpendicular to the feeding direction of the bender  10 . Thus, the first end  80  of the track  78  may be repositioned along the slot  82  in order to align the track first end  80  substantially beneath the central axis  76  of the intake interface  74 . An opposite second end  84  of the track  78  is carried and supported by a trestle support  86 . Suitable adjustment devices are provided to allow leveling and adjustment of the position and of the trestle support  86  and the height of the track second end  84 , such that the location of the track second end  84  in relation to the remainder of the bender  10  may be adjusted to bring the track  78  into substantial parallel alignment with the central axis  76  of the intake interface  74 . 
         [0036]    With reference now to  FIGS. 5-7 , a carriage assembly  88  is slidably mounted to the track  78 . In the illustrated embodiment, the carriage assembly  88  includes a base portion  90  which is shaped to conform to an upper rail portion  92  of the track  78 , such that the base portion  90  is slidably secured along, and carried by, the upper rail portion  92 . The base portion  90  defines a relatively flat, smooth, upper surface  94 . A pivot plate  96  extends in substantially parallel-planar, overlying relationship to the upper surface  94  and is secured thereto via a pin  98  extending perpendicular to the upper surface  94  and the pivot plate  96 . Thus, the pivot plate  96  may rotate about the pin  98  along a plane thereof in relation to the base portion upper surface  94 . In certain embodiments, the pin  98  is defined by a threaded fastener which is configured to engage an internally-threaded hole defined in the upper surface  94 , such that the pin  98  may be tightened in order to secure the pivot plate  96  against rotation in relation to the upper surface  94 . In other embodiments, the pin  98  may be defined by a freely rotatable connection. 
         [0037]    A carriage plate  110  is provided extending generally upward from, and perpendicular to, the pivot plate  96 . The carriage plate  110  is configured to carry and maintain a rotatable disc  114  in parallel-planar relationship to the carriage plate  110 , and to allow receipt of a tube  22  along overlying central portions of the disc  114  and the carriage plate  110 , such that the tube  22  extends generally along the track  78 . For example, in the illustrated embodiment, the carriage plate  110  defines a through opening  112  at a central location thereof, extending perpendicular thereto. A front surface  122  of the carriage plate  110  defines a circular recess  116  extending along a perimeter of the through opening  112 , forming a circular lip  118  along a rear surface  124  of the carriage plate  110  about a periphery of the through opening  112 . The disc  114  is of a diameter approximately corresponding to, but slightly smaller than, the circular recess  116 , such that the disc  114  may be received within the recess  116  and retained therein by the lip  118 . A plurality of retainer members  120  are secured to the front surface  122  of the carriage plate  110  in overlying relationship to the disc  114  via suitable fasteners  128 , each of which is received through the retainer members  120  and is engaged by one of a plurality of gibs  140  extending along the carriage plate rear surface  124 . Thus, the disk  114  is rotatably secured within the recess  116 . In various embodiments, additional locks are provided to allow the disc  114  to be selectively secured against rotation in relation to the carriage plate  110  and unlocked to allow such rotation. For example, in the illustrated embodiment, a pair of recessed, internally threaded bores  130  are provided along the front surface  122  of the carriage plate  110 , adjacent the circular recess  116 . Bolt and washer assemblies  126  are receivable within the bores  130  such that the washer portions overhang the periphery of the disc  114 . Thus, the bolt and washer assemblies  126  may be tightened to frictionally engage the disc  114  or loosened to allow the disc  114  to slide in relation to the carriage plate  110 . Those of skill in the art will recognize other suitable devices and configurations which may be used to accomplish the above-discussed locking of the disc  114  without departing from the spirit and scope of the present general inventive concept. 
         [0038]    In various embodiments, the carriage plate  110  and disc  114  are mounted for slidable adjustment along a vertical direction toward and away from the pivot plate  96 . For example, in the illustrated embodiment, a pair of upright braces  100 ,  102  are provided along each of opposite side edges  104 ,  106  of the pivot plate  96 . The upright braces  100 ,  102  each define a relatively flat, vertical mounting surface  108  adjacent the rear surface  124  of the carriage plate  110 . Each mounting surface  108  defines a plurality of internally-threaded bores  132 , each of which corresponds in overlying relationship to one of a plurality of vertically-extending through-slots  134  defined along the carriage plate  110 . For each bore  132  and corresponding slot  134 , a threaded fastener  136  is provided to extend through the slot  134  and thread into and engage the bore  132 . Thus, the carriage plate  110  is slidably mounted along the mounting surfaces  108  of the braces  100 ,  102 . In several embodiments, the threaded fasteners  136  may each be loosened to allow slidable vertical adjustment of the carriage plate  110  in relation to the pivot plate  96  and tightened to fix the carriage plate  110  in relation to the pivot plate  96 . Thus, the height of the rotatable disc  114  in relation to the central axis  76  of the intake interface  74  is adjustable, such that the center of the rotatable disc  114  may be aligned with the feeding direction of the bender  10 . 
         [0039]    In the illustrated embodiment, an adjustable block  142  is provided to allow controlled adjustment of the vertical positioning of the carriage plate  110  in relation to the pivot plate  96 . More specifically, in the illustrated embodiment, a threaded shaft  144  is rotatably secured to, and extends upwardly from, the pivot plate  96 . A wheel  146  is fixed along, and extends radially outwardly from, the threaded shaft  144 , such that rotation of the wheel  146  effects rotation of the shaft  144  about its axis. The block  142  defines an internally-threaded bore which is mated to the external threads of the shaft  144 . The block  142  is also fixed to the rear surface  124  of the carriage plate  110 . Thus, rotation of the wheel  146  and associated shaft  144  results in translation of the block  142  along the axis of the shaft  144 , thereby sliding the carriage plate  110  up or down along the mounting surfaces  108  of the braces  100 ,  102 . 
         [0040]    As noted above, in various embodiments, the carriage plate  110  and disc  114  are configured to allow receipt of a tube  22  along overlying central portions of the disc  114  and the carriage plate  110 , such that the tube  22  extends generally along the track  78  and toward the intake interface  74 . In the illustrated embodiment, the disc  114  defines a U-shaped cavity  150  extending through the thickness of the disc  114  from a central axis of the disc  114  to an upper perimeter edge of the disc  114 . Likewise, the carriage plate  110  defines a cutout  154  extending from the through opening  112  through an upper edge  152  of the carriage plate  110 . Thus, when the disc  114  is rotated such that the open upper end of the disc  114  overlies the open upper end of the carriage plate  110 , a tube  22  may be received therethrough and positioned along a central axis of the disc  114 . 
         [0041]    With particular reference to  FIG. 7 , and in accordance with several features of the present general inventive concept, a clamp assembly  156  is provided which is removably securable to a central portion of the tube  22  and which is reversibly securable to the disc  114  in order to fasten and maintain the tube  22  along the central axis of the disc  114 . In the illustrated embodiment, the clamp assembly  156  includes a clamping block comprising an upper clamping block portion  158  and a lower clamping block portion  160 . The upper and lower clamping block portions  158 ,  160  define opposing semi-cylindrical recesses  162 ,  164  which may be mated together to allow the recesses to cooperatively surround and frictionally engage the central portion of the tube  22 . The clamp assembly  156  further includes a plurality of fasteners  166  configured to bias the upper and lower clamping block portions  158 ,  160  toward one another to establish frictional engagement between the semi-cylindrical recess portions  162 ,  164  and the tube  22 . 
         [0042]    In the illustrated embodiment, the upper and lower clamping block portions  158 ,  160  cooperate to define a relatively flat and substantially rectangular overall shape, such that the clamp assembly defines opposite first and second major planar surfaces  172 ,  174  which extend generally perpendicular to the central axis of the tube  22  when the tube  22  is mounted within the semi-cylindrical recess portions  162 ,  164 . Suitable fasteners may be provided to mount the clamp assembly  156  to the disc  114  with either the first or the second major planar surfaces  172 ,  174  facing the disc  114  in substantially overlying, parallel-planar relationship with the disc  114  and the carriage plate  110 . For example, in the illustrated embodiment, the lower clamping block portion  160  defines a plurality of through holes  168  which are disposed in a configuration symmetrical about a vertical axis of the lower clamping block portion  160  and which extend perpendicular to the first and second major planar surfaces  172 ,  174 . The disc  114  defines a pair of internally-threaded blind bores  176 , each blind bore  176  being located along the disc  114  to match a location of a corresponding one of the through holes  168  in the lower clamping block  160  such that, when a tube  22  is mounted in the clamp assembly  156  and the clamp assembly  156  is positioned adjacent the disc  114  with the through holes  168  of the lower clamping block  160  in overlying relationship with the blind bores  176 , the tube  22  is received into the U-shaped cavity  150  of the disc  114  and the through opening  112  of the carriage plate  110  and extends along the central axis of the disc  114 . A pair of threaded studs  178  are provided, with each threaded stud  178  being partially threaded into a corresponding one of the blind bores  176  and partially extending outwardly therefrom. Each threaded stud  178  is sized to be matingly receivable through a corresponding one of the through holes  168  of the lower clamping block  160 . Thus, with the clamp assembly  156  positioned adjacent the disc  114 , each threaded stud  178  extends through a corresponding through hole  168  to align the clamp assembly  156  such that the tube  22  extends along the central axis of the disc  114  as discussed above. A fastener nut  170  may then be threaded onto each threaded stud  178  to secure the clamp assembly  156  in the desired position adjacent the disc  114 . 
         [0043]    From the foregoing, it will be recognized that the above-discussed through holes  168  of the lower clamping block  160 , blind bores  176  of the disc  114 , threaded studs  178 , and fastener nuts  170  provide suitable apparatus to mount the clamp assembly  156  in relation to the disc  114  such that a tube  22  mounted in the clamp assembly  156  may be positioned and maintained along the central axis of the disc  114  in either of two orientations, and more specifically, with either of opposite ends of the tube  22  extending along the track  78  toward the intake interface  74  of the bender  10 . It will be recognized that other suitable devices and configurations may be provided by which the clamp assembly  156  may be reversibly secured to the carriage assembly  88 , and such configurations may be used without departing from the spirit and scope of the present general inventive concept. It will further be recognized that the above-described features of the track  78  and carriage assembly  88  allow multi-directional adjustability of the positioning of the tube  22  in relation to the intake interface  74  of the bender  10 , such that the tube  22  mounted in the carriage assembly  88  may be aligned with the central axis of the intake interface  74  of the bender  10 . Thus, in one method of use of the bender  10 , the upper and lower clamping block portions  158 ,  160  may be positioned surrounding a central portion of a substantially straight tube  22  to be bent, with a first end  180  of the tube  22  extending substantially perpendicularly outwardly from the first major planar surface  172  of the clamp assembly  156  and an opposite second end  182  of the tube  22  extending substantially perpendicularly outwardly from the second major planar surface  174  of the clamp assembly  156 . The fasteners  166  of the clamp assembly  156  may be secured and tightened to bias the upper and lower clamping block portions  158 ,  160  toward one another to establish frictional engagement between the semi-cylindrical recess portions  162 ,  164  and the tube  22 . 
         [0044]    The disc  114  may be rotated such that the open upper end of the U-shaped cavity  150  overlies the cutout  154  of the upper edge  152  of the carriage plate  110 . In this configuration, the central portion of the tube  22  may be received downwardly into the U-shaped cavity  150  of the disc  114  and into the through opening  112  of the carriage plate  110 . The clamp assembly  156  may be mounted to the disc  114 , thereby aligning the tube  22  along the central axis of the disk  114  with the first end  180  of the tube  22  extending generally toward the intake interface  74 . The above-described adjustable features of the track  78  and carriage assembly  88  may then be adjusted to align the tube  22  coaxially with the central axis of the intake interface  74 . For example, if necessary, the track  78  may be repositioned along the slot  82  extending beneath the intake interface  74  and the location and/or height of the trestle support  86  may be adjusted to level the track  78  and/or align the central axis of the tube  22  in parallel relationship with the central axis of the intake interface  74 . If necessary, the pivot plate  96  may be rotated in relation to the upper surface  94  of the carriage assembly base portion  90  to adjust the angle of extension of the tube  22  in relation to the track  78  along the horizontal plane. Additionally, the height of the carriage plate  110  from the pivot plate  96  may be adjusted to raise or lower the height of the tube  22  from the track  78 . Once the tube  22  is aligned coaxially with the central axis of the intake interface  74 , the first end  180  of the tube  22  may be fed through the intake interface  74 . With the forming die  12  and pressure die  58  in their respective first positions, the tube first end  180  may be secured to the releasable fastener  28  proximate the leading end  24  of the groove  20  of the forming die  12 , and the pressure die  58  and forming die  12  may be advanced toward their second positions as described above, thereby forming a first bend proximate the tube first end  180 . As the first bend is formed, the carriage assembly  88  may slide along the track  78  toward the intake interface  74 , thereby allowing additional tube to be fed through the intake interface  74 . 
         [0045]    Following formation of the first bend in the tube  22 , the releasable fastener  28  may be released, and if desired, additional portions of the tube  22  may be fed through the intake interface  74  by further sliding the carriage assembly  88  along the track  78  toward the intake interface  74 . Thereafter, the bending process may be repeated, allowing additional bends to be formed along the tube first end  180  toward the central portion of the tube  22 . Most notably, as described above, the disc  114  may be rotated in relation to the carriage plate  110 , thereby allowing the tube  22  to be rotated about its central axis in relation to the forming die  12 . Thus, bends subsequent to the first bend in the tube  22  may be formed at various other angles to the first bend, allowing a wide variety of shapes to be formed along the tube first end  180 . In the illustrated embodiment, angular measuring indicia (not shown) are provided about a perimeter surface of the disc  114 . Marking indicia, such as a line, arrow, or other such indicia, are provided along the carriage plate  110  adjacent the measuring indicia, such that as the disc  114  is rotated, the angle of rotation may be monitored to allow for controlled and measured rotation of the disc  114  in relation to the carriage plate  110 . Once the disc  114  is rotated to a desired angle, the disc  114  may be fixed in relation to the carriage plate  110 , and additional bending of the tube  22  proximate the first end  180  may proceed. 
         [0046]    Following bending of the tube  22  proximate the first end  180 , the clamp assembly  156  may be removed from the disc  114 , and the tube  22  may be removed from the U-shaped cavity  150  of the disc  114  and the through opening  112  of the carriage plate  110 . The clamp assembly  156  may be rotated  180  degrees about the vertical axis of the lower clamping block portion  160 , and the clamp assembly  156  may be remounted to the disc  114  with the second end  182  of the tube  22  extending toward the intake interface  74 . It will be recognized that, due to the symmetry of the through holes  168  in the lower clamping block portion  160 , such rotation and remounting of the clamp assembly  156  may be accomplished while maintaining control and measurement of the above-discussed angle of rotation of the disc  114  in relation to the carriage plate  110 , and hence the angle of rotation of the tube  22  about its central axis. Thereafter, the second end  182  of the tube  22  may be fed through the intake interface  74 . With the forming die  12  and pressure die  58  in their respective first positions, the tube second end  182  may be secured to the releasable fastener  28  proximate the leading end  24  of the groove  20  of the forming die  12 , and the pressure die  58  and forming die  12  may be advanced toward their second positions as described above, thereby forming an additional bend in the tube  22  proximate the tube second end  182 . The above-described process may be repeated as desired to form additional bends in the tube  22  along the tube second end  182 . 
         [0047]    It is noted that the above-described simplified diagrams and drawings do not illustrate all the various connections and assemblies of the various components, however, those skilled in the art will understand how to implement such connections and assemblies, based on the illustrated components, figures, and descriptions provided herein, using sound engineering judgment. Numerous variations, modifications, and additional embodiments are possible, and accordingly, all such variations, modifications, and embodiments are to be regarded as being within the spirit and scope of the present general inventive concept. For example, regardless of the content of any portion of this application, unless clearly specified to the contrary, there is no requirement for the inclusion in any claim herein or of any application claiming priority hereto of any particular described or illustrated activity or element, any particular sequence of such activities, or any particular interrelationship of such elements. Moreover, any activity can be repeated, any activity can be performed by multiple entities, and/or any element can be duplicated. 
         [0048]    While the present general inventive concept has been illustrated by description of several example embodiments, and while the illustrative embodiments have been described in detail, it is not the intention of the applicant to restrict or in any way limit the scope of the general inventive concept to such descriptions and illustrations. Instead, the descriptions, drawings, and claims herein are to be regarded as illustrative in nature, and not as restrictive, and additional embodiments will readily appear to those skilled in the art upon reading the above description and drawings. Additional modifications will readily appear to those skilled in the art. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.