Abstract:
A mandrel support is held along the centerline of a tube being processed by one or more forms attached to the rod at spaced points. Each form includes rubber rollers providing for low-friction movement of the tube thereover. The tube rests on a table comprising two parallel round steel bars which can be variably spaced apart.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to apparatus for feeding tubing over a mandrel support rod which extends through the interior of the tubing to a processing station such as a shear. More particularly the invention relates to the provision of support bodies located at one or more points along the mandrel rod which support bodies carry rollers to provide a low friction engagement with the interior surface of the tubing.  
         BACKGROUND OF THE INVENTION  
         [0002]    U.S. Pat. No. 6,123,003 “Automatic Feed System for Supported Shear Device and Methods of Operating Same” illustrates and describes a system for feeding lengths of steel tubing into a shearing apparatus which may be of the type described in U.S. Pat. No. 6,352,012 issued Mar. 5, 2002. The nature of the shearing apparatus is such as to require internal tooling in the form of a mandrel located in the shear plane area. To precisely locate the mandrel relative to the shear plane, the mandrel is connected to a support rod which extends along a path between a tube entry point and the shear plane.  
           [0003]    Because the mandrel rod may be 20 or more feet long and made of relatively small diameter steel stock, it tends to sag relative to the tube centerline unless support is provided at one or more midpoints. The &#39;003 patent discloses the use of forms  48  and  50  located at spaced midpoints along the mandrel rod and conforming substantially to the inside surface configuration of the tubing. The mandrel rod support forms maintain the mandrel rod essentially along the centerline of the tube as it is fed into the shear station. In the disclosed embodiment, the mandrel rod forms work in combination with a tube support table comprising a pair of spaced apart parallel steel rods or bars. In essence, the table supports the tube and the tube supports the forms and the mandrel rod.  
           [0004]    It has been found that the support forms create friction which adds to the power required from the feed system, the greater the number of forms, the greater the friction.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention has for its principal objective the provision of an improved support form for use in combination with a mandrel rod to substantially reduce the friction between the mandrel rod support forms and the tubing being fed thereover. In general this is accomplished by providing the support form with one or more rollers, the axes of rotation of which are perpendicular to the tube centerline and tube travel axis.  
           [0006]    In the preferred embodiment hereinafter illustrated and described, each support form includes a body mechanically connected into the rod to provide mounting locations for rollers the axes of rotation of which are perpendicular to the longitudinal axis of the mandrel rod. The rollers are axially and angularly spaced apart and are preferably made of hard rubber or other equivalent resilient and durable material. The roller axles are offset relative to the centerline of the tube so each roller contacts the inside surface of the tube at only one point. Where three rollers are used, the contact points are spaced about 120° apart.  
           [0007]    As hereinafter described in greater detail, the mandrel rod and roller support forms work well in combination with a tube support table of the type described and illustrated in FIGS. 9A, 9B and  10  of U.S. Pat. No. 6,352,012 in which I am a co-inventor. That tube support comprises a pair of spaced apart steel bars with round cross-sections so as to contact the outside surface of the tubing at just two tangential contact points. The bars of the support can be adjusted in spacing to accommodate tubing of different diameters.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:  
         [0009]    [0009]FIG. 1 is a perspective view of a tubing recut apparatus employing the invention;  
         [0010]    [0010]FIG. 2 is a detailed cross-sectional view of a complete mandrel rod with one form of embodying the invention;  
         [0011]    [0011]FIG. 3 is a perspective view of a support form embodying the invention;  
         [0012]    [0012]FIG. 4 is a cross-sectional end view of a tube with a support form internally thereof and resting on a table; and  
         [0013]    [0013]FIG. 5 is a perspective view of a portion of the tube support table. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    Referring to FIG. 1 the preferred embodiment of the invention is incorporated into an apparatus  10  for feeding steel tubing  12  to a supported shear  14  by a drive mechanism  15 . As it is being fed to the shear  14  the tubing  12  slides along a support table comprising spaced apart parallel steel bars  16  supported by blocks  18  on an I-beam  20 . Tubing  12  passes over and encloses a mandrel rod  22  having a number of axially spaced apart support forms  26  and  28 .  
         [0015]    Details of the apparatus  10 , inclusive of the drive  15  but exclusive of the novel support form  26  hereinafter described, can be found in U.S. Pat. No. 6,123,003 issued Sep. 26, 2000 the disclosure of which is incorporated herein by reference. As described in the &#39;003 patent, the mandrel rod  22  is held in position by independently operable locks  24  and  25 ; lock  24  is near the tube entry point for the feed system, whereas lock  25  is closer to the shear  14 . The locks  24 ,  25  are farther apart than the maximum length of tube  10 .  
         [0016]    In the present embodiment the mandrel support rod  22  is provided with one or more low friction roller-type support forms  26  over which the tubing  12  passes on its way from the entry lock  24  to the shear  14 . The mandrel rod  22  may further include one or more conventional support forms  28  as shown.  
         [0017]    Referring now to FIGS. 2 and 3 the details of the mandrel rod assembly and the roller support form  26  will be described in detail.  
         [0018]    The mandrel rod  22 , although it may be hollow or solid stock, is much smaller in diameter than the tubing  12  and, if unsupported over a substantial length between the locking mechanism  24  and the mandrel  32 , will sag relative to the centerline of the tubing  12 . Sagging tends to shorten the effective length of the mandrel rod and may result in mislocation of the mandrel tooling relative to the shear plane S. As is apparent to persons skilled in supported shear technology and familiar with the disclosure of the aforesaid U.S. Pat. No. 6,123,003, the mandrel  32  has portions  32   a  and  32   b  which can displace radially relative to one another along a parting line to accommodate relative radial movement of the external shear tooling. To prevent catastrophic destruction of the mandrel during operation of the shear  14 , it is necessary that the parting line between the portions  32   a  and  32   b  be precisely co-located with the shear plane S. Accordingly it is highly desirable to prevent sagging or flexing of the mandrel rod  22  which might disturb this critical relationship.  
         [0019]    For this purpose, roller form  26  is integrated into the mandrel rod  22  by suitable mechanical connectors. In this case a conventional form  28  and a “qualifier” form  30  are also integrated into the rod  22 , the former being near the locking mechanism  24  while the latter is closer to the mandrel  32 . Each roller form  26  comprises a central machined steel body  34  which, as best shown in FIG. 3, is of hexagonal configuration. Straddling the body  34  are cam forms  36  and  38  which steer the leading edges of forwardly fed and rearwardly fed tubing onto the form  26  during in-feed and reverse-feed operations.  
         [0020]    The body  34  has slot-like through apertures  40 ,  42  and  46  machined or otherwise suitably formed therein at axially spaced locations and in uniformly angularly spaced rotation. Each aperture or slot receives and provides rotational clearance for a hard rubber roller  46 ,  48  and  50  respectively. Each roller is supported on an axle rod or pin  52  which is secured across two parallel faces of the body  34  by slots and spring washers. The rollers have internal bushings to reduce friction.  
         [0021]    The axes of rotation of the rollers  46 ,  48  and  50  are all orthogonal to the longitudinal axis of the mandrel rod  22  and are angularly spaced from one another by equal angles of about 120° to provide three contact points with the interior surface of the tubing  12  as best shown in FIG. 4. As also shown in FIG. 4 the centerlines of the bearing pins  52  are not co-located with and do not pass through the centerline of the body  34 . Instead the roller axes are off-set and the diameters of the rollers themselves are substantially smaller than the inside diameter of the tubing  12 . Accordingly there is essentially only one contact point per roller as illustrated in FIG. 4.  
         [0022]    Looking now to FIGS. 4 and 5, the structural associations between the roller support form  26 , the tubing  12  and the rest bars  16  of the support table is illustrated. The support table comprises a series of longitudinally spaced blocks  18  which rest on the steel I-beam  20 . Each block supports a pair of pivot plates  56  which are mounted on the beveled support surfaces  54  of the block  18 . The pivot plates  56  are in turn pivotally connected to the rest table rods  16  as well as to turnbuckles  66  which can be used in combination with additional apparatus hereinafter described to vary the spacing between the rods  16  to accommodate tubing  12  of different diameters.  
         [0023]    More specifically, pivot plate  56  is connected by a pivot  58  to the beveled surface  54  of block  18 . A second pivot  60  interconnects the upper right hand corner of the block  56  to the bar  16 . A third pivot  62  connects the swivel block  56  to the turnbuckle  66  by way of a ball joint  64 . A second ball joint  68  connects the near end of the turnbuckle  66  to a slide block  70  the position of which relative to a base block  72  is controlled by a threaded rod  73  having a pin  74 . A clamp  76  locks the block  70  in the selected position.  
         [0024]    When the turnbuckles  66  are at maximum effective length, either by rotation thereof or by adjustment of the pin  74  relative to the base block  72  to the right as shown in FIG. 5, the pivot plates  56  are rotated relative to the opposite beveled faces  54  of the block  18  to a position which is more upright. This brings the top portions of the blocks  56  closer together to narrow the spacing between the rest bars  16 . In the upright position the rest bars  16  would be a minimum distance apart which is appropriate to support smaller diameter tubing  12 .  
         [0025]    With turnbuckles moved from the upper right to the lower left as viewed in FIG. 5, the swivel plates  56  rotate toward a more supine position. This causes the pivot points  60  at the tops of the swivel blocks  56  to move apart, increasing the spacing between the rest bars  16  to accommodate tubing  12  of larger diameter. The ball joints  64 ,  68  allow the turnbuckles  66  to diverge.  
         [0026]    As illustrated in FIG. 4, the rest bars  16  support the tubing  12  and the roller form  26  supports and centers the mandrel rod  22  relative to the centerline of tubing  12 . Accordingly the mandrel rod  22  maintains a constant and predictable length between locking mechanism  24  and the shear plane S.  
         [0027]    In a typical operation, the locking mechanism  24  is released or opened while the mechanism  25  remains closed. In this condition, tubing  12  is fed by drive mechanism  15  on to the rod  22  over the forms  8  and  26  toward the shear plane S. After the tubing  12  has passed the locking mechanism  24 , the mandrel rod  22  is relocked in the proper position and the lock  25  is opened to allow the tubing  12  to reach the shear plane S of the shear  14 . Assuming an automated feed mechanism  15  is used, the use of one or more roller forms  26  along the length of the mandrel rod  22  dramatically reduces the power requirements of the feed mechanism and substantially reduces the possibility of feed errors due to slippage.  
         [0028]    It will be understood that the use of roller forms having hexagonal bodies and three roller is intended only for purposes of illustration. Roller forms with only one or two rollers are feasible but typically require a larger number of roller forms with closer spacing. The use of three rollers with a triangular arrangement of contact points is preferred.  
         [0029]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.