Abstract:
A stabilizer is disclosed, for suppressing vibrations and whip during the machining long cylindrical work pieces. A mover causes arms to move away from the work piece when the mover is retracted and to move towards the work piece when the mover is extended. The positioning of links and pivots enables the arms to be moved a significant distance when the mover is moved a short distance and thereby permits the use of the stabilizer between a guard and the path of movement of the work piece. The mover is provided with adjustments for changing the force with which the mover acts and to adjust the force applied to the work piece.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a machining stabilizer for the mid-span of long cylindrical work pieces. 
     More particularly, this invention relates to a stabilizer for machines used in cutting cores from long tubular stock. 
     In general, a number of problems are associated with the machining of long cylindrical work pieces. When machining a long work piece supported at only one end, vibrations and whipping of the free end of the work piece are problems that must be addressed to permit proper machining. When machining a long work piece that is supported at both ends, bowing of the mid-span and vibrations are problems that must be addressed to permit proper machining. When machining a long work piece where the machining is being performed in the mid-span, support against tool thrust and configurations that permit the passage of the tool through the location of the stabilizer are important. When the machining is done at high rotational speeds, the problems are exacerbated. 
     In general, the mechanisms of this invention can be modified to deal with the problems associated with the machining of a specific long work piece as recited above without departing from the scope of the invention. To apply the stabilizer to a specific task it is necessary to configure the stabilizer to serve the demands of the specific task. 
     The stabilizer of this invention was developed to stabilize the mid-span of tubular cores being cut on high speed core cutters wherein the method of feeding a new length of core stock involves a head moving along guides to a supply of core stock and acquiring a new length of core stock after which the head is returned to the opposite end of the guides to commence cutting. This process involves the head moving through the location of the stabilizer. The stabilizer of this invention is configured so as to move a pair of stabilizer arms out of the path of the head and return the arms to their operating position once the head has passed their location on the head&#39;s return trip. It is prudent and often required that such machines be fully guarded which adds the requirement that the stabilizer perform its functions within a confined space. Another requirement is that the stabilizer not crush or deform the core and serve to maintain positioning of the core along the centerline of the core cutter while damping out vibrations and suppressing whipping of the free end of the core. 
     2. Description of the Related Art 
     The known prior art is replete with steady rests, guides, and backup tools that are positioned in the mid-span of long work pieces that are being machined. Each of these mechanisms has been given specific configurations to serve specific tasks. These prior mechanisms contain some attributes in common with this invention and other attributes that are specific to the task that they are designed to perform. The following patent references represent the prior art most closely related to the stabilizer of this invention. 
     U.S. Pat. No. 2,958,556 to Samuelson et al. teaches a bottle take out jaw mechanism having a mounting platform, a mover connected to the platform, two arms pivotably connected to the platform, linkages connected to the free end of the mover and to each of the arms and the mechanism operates so that the arms are moved apart as the free end of the mover is advanced towards the work piece. In counter-distinction, the arms of the instant invention are moved apart as the free end of the mover is moved away from the work piece. 
     U.S. Pat. No. 4,810,019 to Brucher teaches a collet chuck for gripping round objects having two arms pivotably connected to a head, a mover connected to the head, arms pivotably connected to the head, multiple rollers rotatably connected to the arms, and the arms are moved by a multiplicity of links connected to the free end of the mover so that when the rollers are in contact with a cylindrical work piece the work piece is centered between the arms. The apparatus operates to move the arms apart when the free end of the mover is moved towards the work piece. 
     U.S. Pat. No. 4,754,673 to Hiestand teaches a self centering steady rest that provides adjustments to compensate for elastic deformation of holding members. The holding members move away form the work piece as the free end of the mover moves away from the work piece. 
     The mover of this invention is self centering and of compact and sturdy construction. The prior art does not teach linkages that connect a mover to arms that are moved away from a work piece when the free end of a mover is moved away from the work piece. Further, the prior art does provide a stabilizer as described, wherein the linkage is such that the arms move through a large angle in response to a short movement of the mover. Further, the prior art does not provide a stabilizer as described wherein the force applied to the work piece by the stabilizer is significantly less than the force present at the free end of the mover. 
     BRIEF DESCRIPTION OF THE INVENTION 
     This invention is for a stabilizer for long cylindrical work pieces comprising: a mounting platform, a mover connected to the platform and the mover has a line of action that is perpendicular to the centerline of the work piece and the mover serves to move a central pivot along the line of action towards and away from the centerline of the work piece, a first arm and a second arm pivotably connected to the mounting platform, and the arms are equally spaced to either side of a plane defined by the centerline of the work piece and the line of action of the mover and the arms project from the mounting platform in the direction of the work piece, and the arms have a length approximately equal to the distance between the platform and the work piece, a first link and a second link pivotably connected to the central pivot and the first link is pivotably connected to the mid-length of the first arm and the second link is pivotably connected to the mid-length of the second arm and the links are angled from the pivot towards the platform, a first roller carrier pivotably connected to the first arm near the end of the arm and on the side of the arm nearest the centerline of the work piece and a second roller carrier pivotably secured to the second arm and on the side of the arm nearest the work piece and the first and second carriers have rotatably secured therein at least two rollers and the rollers are positioned in the carrier so that when the outside perimeters of the rollers are in contact with the work piece the carriers will pivot so that the rollers are in contact with the work piece at equal distances from the centerline of the work piece, and the axes of rotation of the rollers and pivot axes of the pivots are parallel to the longitudinal centerline of the work piece. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic front elevation view of the stabilizer of this invention illustrating the extended and retracted positions of the stabilizer arms relative to the space the arms have to work in. 
     FIG. 2 is an enlarged view of the roller guides in contact with a work piece. 
     FIG. 3 is a front elevation view of a preferred embodiment of the stabilizer of this invention. 
     FIG. 4 is a side elevation view of the stabilizer of FIG. 3 
     FIG. 5 is a perspective view of the stabilizer of FIG.  4 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the drawings like numbers refer to like objects and the proportions of some parts of the invention have been modified to facilitate illustration. 
     Referring now to FIGS. 1 and 2 in which the basic invention is shown schematically. Stabilizer  1  is assembled on mounting platform  2  and mover  3  is connected to platform  2  with the line of action  4  of mover  3  perpendicular to the longitudinal centerline  5  of cylindrical work piece  6  and mover  3  serves to move a central pivot  7  towards and away from centerline  5 . A first arm  8  and a second arm  9  are pivotably connected to platform  2  at pivots  10  and  11  respectively. Pivots  10  and  11  are positioned equal distances from a plane defined by the line of action  4  and centerline  5  and arms  8  and  9  project from pivots  10  and  11  in the direction of work piece  6 , and the arms have a length that is approximately the distance from platform  2  to work piece  6 . First link  14  and second link  15  are pivotably connected to central pivot  7  and first link  14  is pivotably connected to first arm  8  at pivot  12  and second link  15  is pivotably connected to second arm  9  pivot  13  and links  14  and  15  are angled from central pivot  7  towards mounting platform  2 . First roller carrier  16  is pivotably connected to first arm  8  near the free end of arm  8  and on the side of arm  8  nearest to work piece  6 , and second roller carrier  17  is pivotably connected to second arm  9  near the free end of arm  9  and on the side of arm  9  nearest to work piece  6 . First carrier  16  and second carrier  17  have rotatably secured thereon at least two rollers  18 . Rollers  18  are positioned on carriers  16  and  17  so that when rollers  18  are in contact with work piece  6 , carriers  16  and  17  will pivot so that rollers  18  are equidistant from centerline  5 . The axes of rotation of rollers  18  and the pivot axes of all the pivots recited above are parallel to centerline  5 . 
     In FIG. 1, the outer dashed lines serve to show the location of a shield or hood  20  while inner dashed lines serve to show the area that might be passed through by a machining head  21  as it moves along guide  22 . 
     Stabilizers such as stabilizer  1  are to a significant extent task specific. It should be understood, that although the stabilizer as disclosed herein is disclosed as being task specific, the simplicity, compactness and novel attributes of the stabilizer of this invention would suggest that less sophisticated embodiments of the invention would lend it to applications less demanding than those disclosed hereinafter. 
     In FIG. 1 arms  8  and  9  are shown solid in the extended position and dashed in the retracted position. In a core cutting operation a cutting head  21  is traversed along guide  22  past the location of stabilizer  1  with arms  8  and  9  retracted. At the far end of the traverse, the head acquires a new length of core stock and returns to the near end of guide  22 . After head  21  has passed the location of stabilizer  1 , arms  8  and  9  are extended so that rollers  18  contact work piece  6 , which is the core stock, and centers it along the rotational axis of cutting head  21 . 
     It should be noted that pivots  12  and  13  are near pivots  10  and  11  and that links  14  and  15  are angled from pivot  7  towards pivots  10  and  11 . The result is that when central pivot  7  is retracted, a short distance, arms  8  and  9  are pivoted upward and outward a considerable distance and that stabilizer  1  can thereby satisfy the requirement that it provide a clear path for head  21  while operating under hood  20 . 
     It should further be noted that the placing of pivots  12  and  13  near to pivots  10  and  11  and the angling of links  14  and  15  with arms  8  and  9  provides a geometry wherein the inward directed forces, perpendicular to arms  8  and  9  at pivots  12  and  13  are considerably greater than the inward directed forces perpendicular to arms  8  and  9  at carriers  16  and  17 . This enables stabilizer  1  to satisfy the requirement that the stabilizer be self centering and not apply pressures on the work piece that are sufficient to crush or distort a tubular work piece. The principle is that a large force input at pivot  7  will result in a much smaller force output at carriers  16  and  17  and therefore require a large change in force at pivot  7  to produce a small change in force at carriers  16  and  17 . This provides stabilizer  1  with the capacity to make small adjustments in the pressure exerted on work piece  6  by rollers  18 . This permits the “tuning” of stabilizer  1  to damp out vibrations developed in work piece  6 . 
     The above disclosures would enable one skilled in the art to make and use the stabilizer of this invention for its intended purposes without undue experimentation. 
     The following disclosures teach the best mode of practicing the invention known to the inventor at the time of filing his patent application. 
     Stabilizer  31  is task specific to a core-cutting machine wherein a cutting head must pass through the location of stabilizer  31  to acquire a work piece  36  and return with it to a cutting position. Stabilizer  31  then acquires work piece  36  and centers it along centerline  35  and cutting commences. 
     Referring now to FIGS. 3,  4 , and  5  wherein a stabilizer  31  is employed in the cutting of long tubular work piece  36  is disclosed. A mounting platform  32  has a mover  33  secured thereto and mover  33  has a line of action  34  that is perpendicular to centerline  35  of work piece  36  and mover  33  serves to move central pivot  37  towards and away from centerline  35  of work piece  36 . A first arm  38  and a second arm  39  are pivotally connected to platform  32  by means of pivots  40  and  41  and pivots  40  and  41  are equally spaced to either side of a plane defined by line of action  34  and centerline  35  of work piece  36 . Arms  38  and  39  project from platform  32  in the direction of work piece  36  and arms  38  and  39  have a length that is approximately equal to the distance from platform  32  to centerline  35 . A first link  44  and a second link  45  are pivotally connected to central pivot  37  and first link  44  is pivotally connected to first arm  38  at pivot  42  and second link  45  is pivotally connected to second arm  39  at pivot  43  and links  44  and  45  are angled from pivot  37  towards platform  32 . First roller carrier  46  is pivotally connected to first arm  38  by means of pivot  54  near the end of arm  38  and on the side of arm  38  nearest centerline  35  of work piece  36  and a second roller carrier  47  is pivotally secured to the second arm  39  by means of pivot  55  and on the side of arm  39  closest to centerline  35  of work piece  36 . First and second carriers  46  and  47  each have rotatably secured thereon two rollers  48  and rollers  48  are positioned on carriers  46  and  47  so that when the outside perimeters of rollers  48  are in contact with the work piece, carriers  46  and  47  will pivot so that the rollers  48  are in contact with work piece  36  at equal distances from centerline  35 . The axes of rotation of rollers  48  and the pivot axes of the pivots of stabilizer  31  are all parallel to centerline  35 . 
     The mechanisms of stabilizer  1  of FIGS. 1 and 2 are employed in stabilizer  31 . However, the mechanisms are given task specific configurations. Mover  33  is in the form of a cylinder such as a hydraulic, pneumatic, or solenoid cylinder, which extends a mover rod  56  towards and away from centerline  35 . Mover  33  is provided with adjustments  57  which enable the adjustment of the force with which mover rod  56  acts. A transition link  58  serves to locate pivot  37  to the side of mover  33  and towards mounting platform  32  while keeping the line of action of pivot  37  parallel to the line of action  34  of mover  33  and intersecting with centerline  35 . The displacement of pivot  37  to the side of mover  33  and towards platform  32  along with the locations of pivots  42  and  43  near to pivots  40  and  41  permits the raising of arms  38  and  39  with a shorter travel of mover rod  56  than would be possible had pivot  37  been secured directly to the end of mover rod  56 . This permits stabilizer  31  to occupy less space and still perform its tasks. 
     As shown in FIGS. 4 and 5, links  44  and  45  are positioned one on each side of transition link  58  and arms  38  and  39  are offset from each other so that arms  38  and  39  rotate in separate planes perpendicular to centerline  35 . Rollers  48  on carrier  46  project towards arm  39  and rollers  48  on carrier  47  project towards arm  38  so that all rollers  48  are aligned when they are in contact with work piece  36 . 
     The positioning of pivots  42  and  43  relatively close to pivots  40  and  41  also provide mechanics wherein a relatively large change in the force with which mover rod  56  acts will result in a relatively small change in the force with which rollers  48  engage work piece  36 . 
     The use of transition link  58  to position pivot  37  closer to platform  32  than it would be at the end of mover rod  56 , the adjustability of the force with which mover rod  56  acts, the use of short links  44  and  45 , the positioning of pivots  42  and  43  relatively near to pivots  40  and  41 , the offsetting of arms  38  and  39  and the positioning of rollers  48  so that they are in alignment with each other when in contact with work piece  36 , all add incrementally to the capacity of stabilizer  31  to perform the specific tasks required of it in the specific situation in which it is employed. Those specific tasks are to provide an accurate positional hold on work piece  36  without distorting or damaging work piece  36  while damping out vibrations in work piece  36  and in the suppressing of whip in work piece  36  and to be retractable to a configuration that will fit in the small volume between the path of a cutting head and the guards of the machine. 
     The above disclosures would enable one skilled in the art to make and use the stabilizer of this invention without undue experimentation. It should be understood that the stabilizer of this invention could be given many specific configurations to serve specific purposes without departing from the inventive concept of the stabilizer. Therefore, the scope of this invention should not be limited to the embodiments disclosed but the scope of the invention should only be limited by the scope of the appended claims and all equivalents thereto that would be made apparent thereby.