Abstract:
A supply of continuous thin wall tubing which is drawn by a pair of opposed conveyor belts frictionally engaging the outside surfaces of the tubing first through a tube straightening device before the tube walls become engaged with the aforesaid conveyor belts so that straightened tubing is always subjected to engagement with the surfaces on the conveyor belts. The conveyor belts effect a longitudinal driving movement of the tubing into and through a tube cutting device and thence into a tube length control for accurately positioning the tube relative to the tube cutters in the tube cutting device and before the tube is cut. Once the tube length detection circuitry in the tube length control has been satisfied by the positioning of the tubing, the tube cutters in the tube cutting device is activated to sever the tubing.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to a device for driving lengthwise continuous thin wall tubing, to a tube straightening mechanism and to a tube length control mechanism, as well as to a device for driving continuous thin wall tubing through a tube straightening device, to and through a tube cutting device, which tube cutting device is activated by a tube length control which monitors the length of tubing to be cut and activates the tube cutting device only when the precise tube length is presented thereto.  
         BACKGROUND OF THE INVENTION  
         [0002]    This invention arose out of a need to supply tubing cut to specific lengths requested by customers. Over the years, demand for precise lengths in cut tubing has risen and customers have certain needs which require tubing of precise length for use in its equipment and installations. In the past, maintaining precise length in cutting a plurality of tubes to length has been difficult and certain customers have been noted for returning whole lots of cut tubing if one tube in the lot is detected as being out of compliance with the customer&#39;s request, the thought being that if one tube is not cut to the requested length there must be multiple tubes also not cut to the requested length. Further, the customer does not want to have to spend its time sorting the tubing to find those that are not of the requested length.  
           [0003]    In addition to the necessity of accurately controlling tube length, there is the desire to make the cut tube lengths straight. Tube straightening mechanisms are known but all seemingly suffer from the serious disadvantage that much time and tubing is required to effect an accurate adjustment of the next set of tube engaging rollers to accommodate a different size tubing.  
           [0004]    Therefore, it is an object of this invention to provide a system for repetitively cutting continuous length tubing to specific lengths and without the need for human intervention for the purpose of monitoring the cut tubing to make certain that the tubing complies with the customer&#39;s request.  
           [0005]    It is a further object of the invention to provide a system, as aforesaid, wherein the tubing to be cut is first drawn through a tube straightening device by a conveyor belt tube driving mechanism, the straightened tube being frictionally engaged by opposing surfaces of the conveyor belt system to frictionally drive the tubing lengthwise thereof.  
           [0006]    It is a further object of the invention to provide a tube length control for controlling activation of an intermittently driven drive motor for a tube driving mechanism during a dwell period for the drive motor to precisely orient a length of tubing to be cut relative to a tube cutting device and only when the precise location has been determined by the tube length control is the tube cutting device activated to effect a severing of the tube from the continuous length tube supply.  
           [0007]    It is a further object of the invention to provide a tube straightening mechanism which is quickly and easily adjustable to accommodate different diameter tubing thereby substantially reducing the magnitude of the down time for the changeover to different diameter tubing.  
           [0008]    It is a further object of the invention to provide a tube straightening mechanism, as aforesaid, wherein plural pairs of a first set of tube engaging rollers each having tube guiding grooves therein are replaceable with a second set of preadjusted rollers with different size tube guiding grooves therein and into the same support as is used for the first set of tube engaging rollers.  
         SUMMARY OF THE INVENTION  
         [0009]    The objects and purposes of the invention are met by providing a supply of continuous thin wall tubing which is drawn by a pair of opposed conveyor belts frictionally engaging the outside surfaces of the tubing first through a tube straightening device before the tube walls become engaged by the aforesaid conveyor belts so that straightened tubing is always subjected to engagement with the surfaces on the conveyor belts. The conveyor belts effect a longitudinal driving movement of the continuous tubing through the tube straightening mechanism and into and through a tube cutting device and thence into a tube length control for accurately positioning the tubing relative to the tube cutting device and before the tube is cut. Once the tube length detection circuitry has been satisfied by the positioning of the tubing, the tube cutting device is activated to sever the tubing.  
           [0010]    The objects and purposes of the invention are also met by providing a tube straightening mechanism which has interchangeable, preadjusted sets of tube working rollers for quickly facilitating a change over to different size tubing and without wastage of tubing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    Other objects and purposes of this invention will be apparent to persons acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings, in which:  
         [0012]    [0012]FIG. 1 is a top plan view of a tube straightener and drive mechanism for the tubing used in combination with a tube length control for facilitating a cutting of a continuous length tubing into predefined lengths;  
         [0013]    [0013]FIG. 2 is a front elevational view of the tube straightening device and the drive mechanism therefor;  
         [0014]    [0014]FIG. 3 is a left end view of the tube drive mechanism for the tubing shown in FIG. 2;  
         [0015]    [0015]FIG. 4 is a front view of one set of tube working rollers used on the tube straightening device;  
         [0016]    [0016]FIG. 5 is a sectional view taken along the line  5 - 5  of FIG. 2;  
         [0017]    [0017]FIG. 6 is a sectional view taken along the line  6 - 6  of FIG. 5;  
         [0018]    [0018]FIG. 7 is a front view of a tube length control device;  
         [0019]    [0019]FIG. 8 is a right end view of FIG. 7;  
         [0020]    [0020]FIG. 9 is an enlarged fragment of FIG. 7 with a portion of the structure being removed so as to render visible the tube present therein; and  
         [0021]    [0021]FIG. 10 is a sectional view taken along the line  10 - 10  of FIG. 9. 
     
    
     DETAILED DESCRIPTION  
       [0022]    Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words “up”, “down”, “right” and “left” will designate directions in the drawings to which reference is made. The words “forward” and “rearward” as well as “upstream” and “downstream”, will refer to the direction of tube movement through the system, “forward” being the normal flow direction as indicated by the arrows in FIG. 1. The words “in” and “out” will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Such terminology will include derivatives and words of similar import.  
         [0023]    A tube drive mechanism  10  for effecting a longitudinal movement of a continuous length of tubing T through the system S will be described first. In this particular embodiment, two tubes T 1  and T 2  are moved simultaneously through the system S by the tube driving device  10 .  
         [0024]    The tube driving device  10  includes a base frame  11  having parallel tracks  12  thereon guiding a carriage  13  through a controlled reciprocal movement. An upright stanchion  14  is provided on the carriage  13  and is maintained in an upright orientation by a plurality of supports  16  also mounted on the carriage  13 . The upright stanchion  14  is secured to each of the supports  16  by fasteners not illustrated. The fasteners securing the supports  16  to the carriage  13  are illustrated at  17 .  
         [0025]    A conventional worm drive mechanism  18  is provided between the carriage  13  and a base surface  19  upon which the base frame  11  is mounted. The worm drive mechanism  18  is operated by a rotatable hand crank  21 . Upon a rotating of the hand crank  21  about an axis of rotation  22  therefor, the carriage  13  will move in a controlled manner left and right (in FIG. 3) relative to the base frame  11  and the base surface  19  on which the base frame  11  is mounted. Of course, the upright stanchion  14  and the supports  16  therefor will move with the carriage  13 .  
         [0026]    A pair of motor mounting brackets  23  and  24  (FIG. 3) are secured to the upright stanchion  14  and project in a cantilevered manner leftwardly away therefrom. A first motor  26  and right angle drive  27  therefor are connected to the motor mounting bracket  23  as shown in FIG. 1. A second motor  28  and its right angle drive  30  are mounted to the bracket  24  as illustrated in FIG. 3 directly beneath the motor  26 , right angle drive  27  and bracket  23 . The drive motors  26  and  28  are both electrical intermittently driven servomotors which are reversible and controllable with respect to a desired point of stoppage. The purpose of this feature will become more apparent below. The output shaft of the drive motor  26  is connected through a coupling  29  to a rotatable shaft  31 . This connection is also schematically depicted at  49  in FIG. 3. A similar drive arrangement exists for the drive motor  28  and its coupled arrangement to a drive shaft  32  which is schematically illustrated as at  50  in FIG. 3. The bearings rotatably supporting the rotatable shafts  31  and  32  are not illustrated but can be oriented within the respective motor mounting brackets  23  and  24 .  
         [0027]    In this particular embodiment, the rotatable shaft  32  is drivingly connected to a spur gear  33  which has a toothed belt driving wheel  34  fastened thereto. A further spur gear  36  and toothed belt driving wheel  37  are freely rotatably supported on the shaft  31 . The spur gears  33  and  36  are meshingly engaged with one another so that a driving of the spur gear  33  by the motor  28  will effect a simultaneous rotation of the spur gear  36  and toothed belt driving wheel  37  secured thereto.  
         [0028]    Shafts  38  and  39  are also provided on and cantilevered from the stanchion  14 , the axis of the shaft  38  being contained in the same horizontal plane as the axis of the shaft  31  whereas the axis of the shaft  39  is in the same horizontal plane as is the axis of the shaft  32 . Toothed belt driving wheels  41  and  42  are freely rotatably supported on the shafts  38  and  39 , respectively. An endless and toothed belt  43  is mounted on the toothed belt driving wheels  36  and  41 . A further endless and toothed belt  44  is mounted on the toothed belt driving wheels  34  and  42 . The reach  46  of the belt  43  and the reach  47  of the belt  44  are urged toward one another by a conventional pressure applying device  48  schematically illustrated in FIG. 2. As is illustrated in FIG. 3, the endless belt  47  has a plurality of side-by-side oriented grooves  51 ,  52  and  53  therein. In this particular embodiment, each of the grooves  51 ,  52  and  53  can be of a differing diameter to accommodate a different diameter tube working therewith and as will be explained in more detail below. The surface  54  of the belt  43  is smooth as is depicted in FIGS. 1 and 3. The surface  54  of the belt  43  opposing the surface of any selected groove  51 ,  52  or  53  in the belt  47  is configured to frictionally engage a tube T passing therebetween.  
         [0029]    The drive motor  26  and right angle drive mechanism  27  effects a driving of a spur gear  57  in the same manner that the drive motor  28  effects a driving of the spur gear  33 . The spur gear  57  mates with a further spur gear  58  so that the belt driving wheels  59  and  61  secured, respectively, to the spur gears  57  and  58 , will be driven by the drive motor  26 . Similar belt supporting wheels are freely rotatably mounted on the shafts  38  and  39  in a manner similar to the wheels  41  and  42 . An endless belt  62  is mounted on the belt driving wheel  59  and the drive wheel freely rotatably supported on the shaft  38 . A further endless belt  63  is mounted on the belt drive wheel  61  and a corresponding belt support wheel freely rotatably supported on the shaft  39 . As is depicted in FIGS. 1 and 3, the outer surface of the belt  62  is smooth whereas the outer surface of the belt  63  has plural grooves  66 ,  67  and  68  therein. The size of the grooves  66 ,  67  and  68  can correspond, respectively, to the size of the grooves  51 ,  52  and  53  or be in some other relation thereto.  
         [0030]    Referring now to FIG. 1, a tube supply is provided and, in this particular embodiment, is the source for two tubes T 1  and T 2  preferably (but not necessarily) of the same size. The tube supply is generally in coil format and the tubes T 1  and T 2  are drawn from the tube supply through a tube straightening mechanism  70  by the tube driving device  10 , particularly, the tube T 1  being received between the opposing surfaces of the belts  62  and  63  and the tube T 2  being received between the opposing surfaces of the belts  43  and  44  as schematically depicted in FIG. 3.  
         [0031]    The tube straightening mechanism is comprised of two sections  71  and  72 , each section capable of working two tubes T 1  and T 2  at a time. That is, section  71  has two subsections  71 A and  71 B whereas section  72  has two subsections  72 A and  72 B. Since the construction in each of the subsections is generally the same, only the subsection  71 A will be described in detail, it being understood that this description will be applicable to the remaining subsections.  
         [0032]    The section  71  of the tube straightening mechanism  70  includes a vertically upstanding plate  73  having along an upper edge thereof a trough  74  into which is reciprocally received a locking bar  76 . The plate  73  also has a plurality of holes  77  (FIG. 5) of a first size extending therethrough and holes  78  of a second size extending therethrough. As is best illustrated in FIG. 5, each hole  78  is straddled by a pair of holes  77 . In this particular embodiment, subsection  71 A includes two sets of tube working rollers  79  and  81  spaced along the length of travel of the tube T 2  and one set of tube straightening rollers  82 . Each of the tube working rollers  79  and  81  as well as the tube straightening rollers  82  are of an identical construction and, therefore, only the tube working roller set  79  will be discussed in detail with particular reference to FIGS. 4 and 5.  
         [0033]    The tube working roller set  79  (FIG. 5) includes a shaft  83  one end of which is removably received in the hole  77  oriented to the right of the hole  78 . The shaft  83  projects in a cantilevered fashion from one side of the plate  73  through a hole  85  in a lever  84  to pivotally support the lever  84 . A tube working roller  86  is rotatably supported on the shaft  83 . The axis of rotation for the roller  86  coincides with the longitudinal axis of the shaft  83  as well as the pivot axis for the lever  84 . Midlength of the lever  84  there is provided a hole  87 , which hole is elongated in a direction transverse of the length of the lever as illustrated in FIG. 4. A shaft  88  having at one end a diameter corresponding to the diameter of the hole  78  is received in the hole  78  and, at the other end, has a stub shaft section  89  received in the hole  87  in the lever  84 . An internally threaded hole  91  extends through the stub shaft section  89 . The lever  84  also has a pair of holes  92  and  93  that are axially aligned with one another as well as axially aligned with the internally threaded hole  91 . An externally threaded bolt  94  extends through the axially aligned holes  92  and  93  and is threadedly engaged with the threads in the hole  91 . The bolt  94  has a nut  96  thereon oriented on a side of the lever  84  remote from the head  97  thereof. The nut is fixed to the bolt by a pin  98  so that the bolt  94  and nut  96  will simply rotate in the axially aligned holes  92  and  93  to effect a pivoting of the lever  84  about the axis of the shaft  83  to and between positions depicted in broken lines in FIG. 4. A stub shaft  99  is received in a hole  101  in the lever  84  on a side of the hole  87  remote from the hole  85 . A tube working roller  102  is rotatably supported on a reduced diameter section of the stub shaft  99  as best illustrated in FIG. 5. The tube working rollers  86  and  102  are each maintained on their respective shafts by pins  103  (FIG. 2) received in grooves  104 . Since as is illustrated in FIG. 2 the tube working rollers  86  and  102  are oriented on opposite sides of the longitudinal axis of the tube T 2  which is to be straightened, it can be seen that a pivoting of the lever  84  will alter the degree of working on the tube T 2 . More specifically, as the tube working roller  102  of the tube working roller set  79  is moved toward or away from the longitudinal axis of the tube T 2 , as well as toward and away from the roller  86  in the tube working roller set  81 , the tube T 2  will be worked sufficiently in an effort to straighten same. Similarly, and since the tube working rollers in the tube working roller set  79  are identical in construction to the rollers in the tube working roller set  81  and the tube straightening roller set  82 , the tube T 2  will be sufficiently worked so that by the time it reaches the two tube sizing rollers  106  and  107 , the tube will be effectively straightened in a first plane thereof.  
         [0034]    The two tube sizing rollers  106  and  107  served to return the peripheral surface of the tube T 2  to a cylindrical format prior to a movement of the tube T 2  onto the next section  72 A of the tube straightening mechanism  70 . The sizing roller  107  is mounted on a lever  108  that is pivotally secured to the plate  73  by an axle  109  and has an adjustment mechanism  111  identical in nature to the adjustment mechanism for effecting a pivoting of the lever  84  as depicted in FIG. 4.  
         [0035]    Each of the two tube working roller sets  79  and  81  as well as the tube straightening roller set  82  is releasably mounted on the plate  73 . In order to accommodate this releasable connection to the plate  73 , the shaft  88  includes an annular groove  112  therein. The locking bar  76  includes a flat edge  113  which is received in the annular groove  112  in a first position of the locking bar  76  so as to prevent withdrawal of the shaft  88  as well as the shaft  83  from the respective holes  78  and  77 . However, upon a moving of the locking bar  76  to the right in FIG. 6 until an arcuate notch  114  becomes concentric with the radius for the outer surface of the shaft  88 , the shaft  88  will be permitted to exit from the hole  78  accompanied by a withdrawal of the shaft  83  from the hole  77 . As a result of this releasable connection feature, a similar set of rollers with different diameter grooves  116  therein can be used for working different diameter tube emanating from the tube supply.  
         [0036]    The aforesaid similar sets of rollers will all usually be preadjusted, due to them having been used previously, so that little or no additional adjustment is required in the form of an additional set-up procedure. Thus, the operation of the system S will be down for only a relatively short interval of time during the change over while the similar sets of rollers is substituted for each of the previously used sets.  
         [0037]    As stated above, the subsections  71 B,  72 A and  72 B each comprise sets of rollers identical to those that have been described above with respect to subsection  71 A. Thus, further discussion about the orientation of the rollers on the respective plates  73  and  117  is believed unnecessary. On the plate  117 , however, there is provided two locking bars  118  and  119  comparable to the locking bar  76  on the plate  73 . Since the subsections  72 A and  72 B are horizontally spaced from one another, as opposed to back-to-back as is the case with the subsections  71 A and  71 B, two locking bars  118  and  119  are needed in order to releasably lock the sets of working rollers and straightening rollers to the plate  117 .  
         [0038]    Generally, as the tubes T 1  and T 2  exit the two sets of sizing rollers  106 A,  107 A and  106 B,  107 B at the left end of the subsections  72 A and  72 B, the tubes T 1  and T 2  will be sized (i.e., cylindrical) and straight prior to their entry into association with the immediately adjacent tube driving mechanism  10 . As a result, the length of tube T 1  and T 2  entering the associated groove in the selected belts  44  and  63  will remain in the selected groove due to the prior straightening of the respective tube. In other words, there will be no tendency for the length of tubes T 1  and T 2  to wander left and right as the tube travels between the opposing surfaces of the belt pairs  43 ,  44  and  62 ,  63 .  
         [0039]    If a different size tube is provided by the tube supply, the tube driving mechanism can be shifted left and right (FIG. 3) by turning the hand crank  21  about the axis of rotation  22  therefor to bring an appropriate groove  51 - 53  as well as  66 - 68  into proper alignment with the longitudinal axis for the respective tube to facilitate a driving of that tube therethrough.  
         [0040]    As the tube exits the tube driving mechanism  10 , it enters and passes through a tube cutter device, such as the device disclosed in U.S. Pat. No. 3,568,488. According to this patent, and during a dwell time in an intermittent drive cycle provided by the drive motors  26  and  28 , each tube is tightly gripped and placed under tension, and while the tube is tensioned, a cutting tool makes and annular cut in the periphery of the tube which penetrates into the wall of the tube. With the tension applied to the tube, the tensile strength of the tube wall not yet severed is exceeded, and the tube breaks. Consequently, the tube material is not cut entirely through, but partially cut and partially pulled apart at the cutting point. Therefore, the inwardly extending bur is minimized by the extruding caused by the pulling apart action. The subject matter of the aforesaid patent is to be incorporated herein by reference.  
         [0041]    As the drive motors  26  and  28  continue to intermittently drive the belts, tubing is pulled through the tube straightening mechanism  70  and delivered to and through the tube cutter device into a tube length control mechanism  120 , an example of which is illustrated in FIGS.  7 - 10 . As is illustrated in FIGS. 7 and 8, the tube length control mechanism includes a frame  121  having a pair of vertically upstanding legs  122  and  123  interconnected by horizontally extending bracing  124  oriented on opposite sides of the legs  123  adjacent the upper ends thereof. Further horizontal bracing components  126  are fastened to opposite sides of the upstanding legs  122  and  123  and each have affixed thereto an elongate angled profile, here a V-shaped profile,  127  wherein the legs of the angled profile open outwardly in opposite horizontal directions. A cross section of the elongate strip of angled profile  127  is better illustrated in FIG. 10. A mating elongate strip of angled profile  128  is provided for each profile  127 , with each profile  128  being fixedly secured to a lever arm  129  pivotally supported for movement about an axis  131  of an axle  132  secured to a horizontal bracing component  133 . The legs of each of the V profiles  128  open outwardly in a direction directly opposing the legs of the V profiles  127 . A clevis  134  is provided which is attached to and extends away from a side of the axles  132  remote from the angled profiles  128  and each is acted upon by an actuator  136  for effecting a pivotal movement of the levers  129  between the broken line position and the solid line position illustrated in both of FIGS. 8 and 10. When the lever arms  129  are in the solid line position illustrated in FIG. 10, the angled profiles  127  and  128  mate to define a rectangular opening  137  adapted to receive therein a tube, namely, a tube T 2  as illustrated in FIG. 10. The tube T 1  is received into an identical array on the right hand side of the upstanding legs  123  as depicted in FIG. 8. Each of the tubes T 1  and T 2  are guided into a corresponding opening  137  between the angled profiles  127  and  128  by a funnel mechanism  138  (FIG. 7).  
         [0042]    An elongate horizontal bar  141  is secured to the upstanding legs  122  and  123  and has a plurality of horizontally extending holes  142  horizontally spaced therealong. In this particular embodiment, each of the holes is precisely one-half inch from the next adjacent hole. The elongate bar  141  is oriented above the angled profiles  127  and  128  as best depicted in FIGS. 7 and 10. A similar elongate horizontally extending bar  143  is secured to and extends between the upstanding legs  122  and  123  and is oriented below the angled profiles  127  and  128 . The bar  143  also has a plurality of horizontally extending holes  144  therein, each hole  144  being precisely spaced one-half inch from the next adjacent hole and oriented directly beneath a hole  142 .  
         [0043]    A light sending unit  146  is mounted to the elongate bar  141  using a selected hole or holes  142  in the elongate bar  141  for effecting an appropriate positioning thereof measured from the location of the cutter blade in the tube cutter device schematically shown at  150  in FIG. 1. Screws  147  are used to secure the light sending unit  146  to the elongate bar  141 . The light sending unit  146  is configured to send a light beam  148  of substantial width W 1  (FIG. 9) constituting a multiple of the half-inch spacing between the holes  141  and  144 .  
         [0044]    The light sending unit  146  has a pair of spacer tabs  149  extending into the path of movement of the elongate angled profiles  127  and  128  so as to prevent distal edges of the legs of the angled profiles  127  and  128  from touching one another at a location therebetween so as to permit the full width W 1  of the light beam  148  to enter the open space  137  between the angled profiles  127  and  128  as schematically depicted in FIG. 10.  
         [0045]    A light detecting unit  151  is mounted to the bar  143  and is secured thereto by a plurality of screws  152  received in holes  144  oriented directly beneath the holes  142  into which are received the aforesaid screws  147 . As a result, the light detecting unit  151  is oriented directly below the light sending unit  146  as illustrated in FIG. 9. The light detecting unit  151  has a pair of spaced spacer tabs  153  extending into the path of movement of the elongate angled profiles  127  and  128  so as to prevent the distal edges of the legs of the angled profiles  127  and  128  from contacting one another between the spacer tabs  153 . As a result, a full width W 1  of the light beam  148  emanating from the light sending unit  146  will be fully detected by the light detecting unit  151  through the gap created by the spacer tabs  149  and  153 .  
         [0046]    As a respective tube T 1  or T 2  enters the open space  137  between the angled profiles  127  and  128  on opposite sides of the upstanding legs  123 , the leading end  157  (FIG. 9) of the tube will enter the region whereat the light beam  148  is located. The drive motors  26  or  28  will be preprogrammed to stop at this time. A portion of the leading end  157  of each tube, here the tube T 2  (FIG. 9), will intersect the width W 1  of the light beam  148  and the light detecting unit  151  will detect a reduced width W 2  of light in the light beam  148  and a control  154  will generate a signal to the controlling reversible motor  26  or  28  to either an advance of the respective tubes T 1  and T 2  leftwardly or rightwardly (FIG. 9) to locate the leading ends  157  of the tubes T 1  and T 2  precisely at the preselected locations from the cutter blades  150 . When the control  154  has so noted from the light detecting units  151  that the leading ends  157  of the tubes T 1  and T 2  have been appropriately located, only then will a signal be sent by the control  154  to the tube cutter device to cause the cutter blades  150  to cut the tubes T 1  and T 2  thereat. Following a completion of a cutting operation, the control  154  will activate the actuators  136  to cause the lever arms  129  and associated profiles  128  to pivot to the broken line position thereby enabling the tubes T 1  and T 2  to fall under the effect of gravity into a respective trough  156 .  
         [0047]    The light sending unit  146 , the light detecting unit  151  and the control  154  therefor are conventional devices available from KEYENCE CORP. OF AMERICA, particularly, model number LX2-13(w).  
       OPERATION  
       [0048]    Although the operation of the mechanism described above will be understood from the foregoing description by skilled persons, a summary of such description is now given for convenience.  
         [0049]    Tubing T is drawn from the tube supply through two sections  71  and  72  of a tube straightening mechanism  70  by a belt drive tube driving mechanism  10 . The tube drive mechanism  10  is adjustably movable laterally by rotating the hand crank  21  so that an appropriately sized one of the grooves  51 - 53  and  66 - 68  in the lower one of the pairs of belts will align with the longitudinal axis of the now straightened tube T 1  and T 2  exiting the tube straightening mechanism  70 . The tube pulled from the tube supply through the tube straightening mechanism  70  is thence delivered to and through the tube cutter device to a tube length control mechanism  120  which senses the length of tube between the cutter blades  150  in the tube cutter device and the leading end  157  of the tubes and once the leading ends of the tubes are appropriately located by appropriate control of the intermittent operation of the motors  26  and  28 , a signal is sent from the control  154  in the tube length control mechanism  120  to the tube cutter device to effect a cutting of one tube or two tubes by the cutter blades  150 , which tube or tubes are thereafter permitted to drop into a trough  156 .  
         [0050]    Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.