Abstract:
A keyless tooling system for the production of continuous seam-welded tubes is disclosed wherein the tube forming rolls are selectively held in fixed position on supporting spindles by an expandable tapered bushing. The bushing may be caused to move to permit contraction in annular dimension facilitating the removal of the associated forming roll during a mill changeover.

Description:
[0001]    This application claims the benefit of U.S. provisional patent application Serial No. 60/286,625, filed Apr. 20, 2001.  
         BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention:  
           [0003]    This invention relates generally to a mill for the production of continuous seam-welded tubes or pipes and, more particularly, to a changeover system for changing roll tooling quickly, efficiently, and safely.  
           [0004]    2. Description of the Prior Art:  
           [0005]    Many mill sections of the prior art utilize rolls journaled between front and rear mill stands wherein the rolls are keyed to the journaled spindles. Such arrangements function well insofar as the metal forming operation is concerned, but are time consuming during changeover of tooling when it is necessary to remove the keys to successfully release the rolls to their respective spindles.  
           [0006]    Changeover systems are an important part of current “high tech” mill lines. Recent innovations in this area for both small and large diameter mills are effective for changing roll tooling. Shaping stands for production of large or small structural products have received a significant recent engineering effort to make roll changing quicker and easier. Cassette-type shaping stand designs are provided to automatically changeover and set roll gap. These developments provide the mill operators the ability to reduce downtime for roll changeover from hours to minutes.  
           [0007]    It has been found that in certain instances it is desirable to quickly changeover a set of forming rolls without the utilization of the cassette-type changeover system Therefore, the requirement of quickly, efficiently, and safely removing one set of forming rolls and replacing the same with a new set becomes manifest.  
           [0008]    An object of the present invention is to produce a tooling system to facilitate the desired tooling changeover.  
           [0009]    Another object of the invention is to produce a tooling system wherein the forming rolls are secured to the respective supporting spindles by a tapered bushing.  
           [0010]    Still another object of the invention is to produce a keyless tooling system for readily securing a forming roll to a supporting spindle.  
           [0011]    Another object of the invention is to produce a keyless tooling system employing a tapered bushing for securing a forming roll to an associated supporting spindle.  
           [0012]    Another object of the invention is to produce a keyless tooling system employing an associated driving member for locking and unlocking a bushing for securing a forming roll to a supporting spindle.  
           [0013]    A further object of the invention is to produce a keyless tooling system incorporating an expandable bushing for securing a forming roll to a supporting spindle.  
         SUMMARY OF THE INVENTION  
         [0014]    The above objects and advantages of the invention may typically be achieved by a tube mill apparatus for the production of continuous seam-welded tubes comprising: a tapered spindle having a tapered outer surface journaled for rotation between front and rear stands of the tube mill; an expandable tapered bushing juxtaposed on the tapered outer surface of the spindle; forming roll having a hollow central bore carried by an outer surface of the bushing; first driver for moving the bushing in a first direction to cause expansion of the bushing between the tapered surface of the spindle and hollow central bore of the forming roll; and second driver for moving the bushing in a second direction to cause contraction of the bushing between the tapered surface of the spindle and hollow central bore of the forming roll. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The above, as well as other objects and advantages of the invention, will become readily manifest to those skilled in the art from considering the following detailed description of an embodiment of the invention when considered in the light of the attached drawings, in which:  
         [0016]    [0016]FIG. 1 is an elevational view partially in section of the front and rear stands of the forming section of a tube mill embodying the features of the present invention;  
         [0017]    [0017]FIG. 2 is an enlarged fragmentary view of the upper forming roll assembly illustrated in FIG. 1 more clearly illustrating the mechanism for expanding and contracting the tapered bushing of FIG. 1;  
         [0018]    [0018]FIG. 3 is an end view of the tapered bushing illustrated in FIGS. 1 and 2;  
         [0019]    [0019]FIG. 4 is a sectional view of the tapered bushing illustrated in FIG. 3 taken along line  4 - 4  thereof; and  
         [0020]    [0020]FIG. 5 is an end view of the tapered bushing illustrated in FIGS. 3 and 4 taken from the end opposite that illustrated in FIG. 3. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    Referring to the drawings, there is illustrated the rear and front stands of the forming section of a tube mill for the continuous production of seam-welded tubing. More specifically, there is illustrated a keyless spindle arrangement for coupling the cooperating forming rolls to their respective supporting spindles.  
         [0022]    [0022]FIG. 1, in particular, illustrates a forming stand assembly of a tube mill including a rear stand  10  and a front stand  12 . A pair of cooperating forming rolls  14  and  14 ′ are supported for rotation on an upper spindle  16 , and a lower spindle  16 ′, respectively. It will be noted that the spindles  16  and  16 ′ are tapered.  
         [0023]    The forming rolls  14  and  14 ′ are provided with hollow interior bores adapted to receive the respective spindle  16  and  16 ′. In order to maintain snug positive engagement between the forming rolls  14  and  14 ′ and the respective spindles  16  and  16 ′, there are provided tapered bushings  18  and  18 ′, respectively. The bushings  18  and  18 ′ are typically identical with one another. Accordingly, only a single bushing element  18  is clearly illustrated in FIGS. 3, 4, and  5 .  
         [0024]    Since the structure and the interrelationship between the forming rolls  14  and  14 ′, the respective spindles  16  and  16 ′, and the tapered bushings  18  and  18 ′ are identical in respect of the upper and lower roll assemblies, only the upper assembly will be described in detail. The upper spindle  16  is adapted to extend between the rear stand  10  and the front stand  12 . The respective ends of the spindle  16  are suitably journaled in the rear stand  10  and the front stand  12 . The intermediate portion of the spindle  16  is provided with a tapered surface  20 . The tapered surface  20  is adapted to receive the tapered bushing  18  and the associated upper forming roll  14 . It will be understood that the forming rolls  14  and  14 ′, and the associated respective tapered bushings  18  and  18 ′ are either placed onto or removed from the respective spindles  16  and  16 ′ during changeover when the front stand  12  is moved away from the normal operating position as illustrated in FIG. 1.  
         [0025]    The tapered bushing  18  is typically formed from a cylindrical member  22  of alloy spring steel. The internal surface  24  of the cylindrical member  22  is machined to form a tapered central bore. Finally, slots  26  are formed by a machining operation, such as, for example milling or sawing. The slots  26  are formed to extend generally parallel to one another in spaced relation. Alternate end portions of the slots  26  remain joined together by bridges  26 ′ at one end and bridges  26 ″ at the opposite end.  
         [0026]    When the selected forming rolls  14  and  14 ′ are positioned on the respective spindles  16  and  16 ′ with the associated tapered bushings  18  and  18 ′ in place, the front stand  12  is moved into operative position and the appropriate clamping nuts  28  and  30  are applied to the appropriate spindles  16  and  16 ′. As the clamping nuts  28  and  30  are tightened, associated sleeves  32  and  34  of the journal assemblies are urged against the outer end of the respective tapered bushings  18  and  18 ′. As clearly illustrated in FIG. 2, as the clamping nut  28  is tightened, the sleeve  32  is forced against the end of the tapered bushing  18  causing the bushing to slide toward the rear stand  10  across the cooperating tapered surface of the upper spindle  16 . The tapered bushing  18  expands to effectively form a tight fit between the upper forming roll  14  and the spindle  16 . The same procedure is accomplished between the lower forming roll  14 ′ and the respective spindle  16 ′. It will be understood that the spindles  16  and  16 ′ are driven by associated drive motors to cause powered rotation of the forming rolls  14  and  14 ′.  
         [0027]    When it is desired to change the forming rolls  14  and  14 ′ to produce a tubing of another diameter or wall thickness, the tapered bushings  18  and  18 ′ must be released by contracting the bushings. In the illustrated embodiment, the changeover may be effected by a pressure fluid actuated system which includes centrally disposed bores  36  and  38  formed in the spindles  16  and  16 ′. Since the structure is substantially identical for each of the spindles  16  and  16 ′, only the upper spindle  16  will be described in detail. One end of the bore  36  is in communication with a fitting  40  provided with a zerk fitting  42  for the reception of pressure fluid. The opposite end of the bore  36  communicates with a fluid conduit  44  which is formed to completely extend circumferentially around a fitting  46 . The outlet of the conduit  44  is provided with an annular ring  48  which is adapted to slide outwardly of the rear stand against the tapered bushing  18  to urge the bushing towards the opposite end of the spindle  16  allowing the bushing to contract and thereby effect a loosening of the forming roll  14 .  
         [0028]    The lower forming roll  14 ′ is tightened and loosened in the same manner as the upper forming roll  14 .  
         [0029]    In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be understood that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.