Abstract:
An apparatus and process is disclosed for spinning circumferential articles with constant length end surfaces. The article is first spun to define the circumferential surface, and a mandrel is then introduced, whereby the mandrel has a shoulder positionable adjacent to the end surfaces. The end surfaces, while supported by the mandrel, are further spun, and the material is flow formed into the shoulder, to define a constant and defined length to the article.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    It is well known in the art of spinning to provide a spinning machine including a plurality of chuck jaws, which confixedly hold material to be spun, such as a tubular member. The tubular member is spun in the chuck and a roller is moved transversely of the longitudinal length of the material, such that the roller engages the tube. The roller is then moved in an axis parallel to the longitudinal axis of the tubular member. In this way, the material of the tubular member can be formed into various configurations, such as a reduced diameter neck portion.  
           [0002]    As efficient as the spinning process is, one of the difficulties is controlling the length of the end edges of the tubular member while spinning and the overall length after spun. Any discontinuity in the length of the end edges is exaggerated, such that after spinning, the end edges of the material spun could be rather jagged even including sinuous-shaped contours. This discontinuity of the end edges has heretofore required secondary operations to provide a constant length end. Not only is the discontinuity of the end edges a disadvantage, but the secondary operation more than likely requires removal of the tubular member from the chuck jaws, thereby losing any longitudinal registration with the tooling.  
         SUMMARY OF THE INVENTION  
         [0003]    The objects of the invention have been accomplished by providing a method of spinning a material to a circumferential configuration having a constant length, where the method comprises multiple steps. The material to be spun is first provided and held. The material is next spun about a longitudinal axis. A tooling roller is moved tangentially towards the spinning material, and the roller is then moved along an axis parallel to the longitudinal axis, thereby spinning the material to a radially different configuration. A shoulder is provided with a predefined definition, and the material is flow formed such that free end edges of the material abut the shoulder to conform the end edges to the predefined definition.  
           [0004]    In one method the shoulder is provided as a transverse plane, transverse to the longitudinal axis. The shoulder can be provided in the form of a mandrel. The mandrel can be provided in a dimension generally along the longitudinal axis, having a first end portion with a constant first end diameter to extend below the free end edges, and a second diameter, spaced from the first end diameter, and having a diameter larger than the first end diameter forming the shoulder therebetween. The material can be provided tubular in shape. The material can be held by a chuck, where the chuck spins about the longitudinal axis to spin the tubular material. The tooling roller is moved in a direction from the chuck towards the mandrel. The free end edges are spun to a diameter less than the first end diameter, and the first end of the mandrel is forced into the tubular spun end. The flow-forming step is performed by moving the tooling roller along the material, forcing the material against the first end portion of the mandrel, thereby moving the material towards the shoulder.  
           [0005]    In another aspect of the invention, an inner member is provided, profiled for receipt within the tubular member, wherein the tubular member is spun to encapsulate the inner member. In this manner a catalytic converter is formed by the further steps of inserting at least one monolith substrate into the tubular member, prior to the spinning process, and spacing the monolith from an end to be spun; positioning a funnel shaped heat shield into the tubular member, with a reduced diameter section directed outwardly, and with an enlarged diameter section adjacent to the substrate; and spinning the tubular end to generally conform to the shape of the funnel shaped heat shield.  
           [0006]    The mandrel can be provided with a frusto-conical shaped portion, extending continuously from the second diameter. The second diameter is less than a diameter of the tubular member, and the frusto-conical shaped portion has an end diameter larger than a diameter of the tubular member. The mandrel, prior to the spinning step, is positioned with the frusto-conical shaped portion in abutment with the tubular member, and the tubular member is spun by moving the tooling roller in a direction from the mandrel towards the chuck, thereby collapsing the tubular member against the frusto-conical shaped member. The mandrel is thereafter gradually backed out, and the material is continuously spun to a further reduced diameter portion.  
           [0007]    In another aspect of the invention, an apparatus for spinning a material workpiece to a circumferential configuration having a constant length, is comprised of a spinning chuck having jaws to hold a material workpiece to be spun; and a mandrel having a first end having a constant diameter, which terminates into a shoulder, the mandrel being longitudinally movable into an open end of the workpiece.  
           [0008]    The mandrel can further comprise a frusto-conical portion extending from the mandrel first end, the frusto-conical portion enlarging away from the mandrel first end, whereby an end of the frusto-conical portion forms the shoulder. The frusto-conical portion is longitudinally movable relative to the mandrel first end. The mandrel first end has a holding mechanism for holding an item to be inserted into the material workpiece. The holding mechanism is comprised of telescopically movable members, connected at their front ends by way of a toggle link, whereby the members have a first position wherein the toggle links form the holding member and have a radial dimension greater than the mandrel first end, and a second position whereby the toggle links have a radial dimension equal to or less than the mandrel first end. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0009]    FIGS.  1 A- 1 F show diagrammatically a spinning process including the provision of a mandrel to form the spun end with a constant longitudinal length;  
         [0010]    FIGS.  2 A- 2 F show an apparatus and process steps substantially according to the process shown in FIGS.  1 A- 1 F;  
         [0011]    FIGS.  3 A- 3 I show a further embodiment of the apparatus and the associated process steps;  
         [0012]    FIGS.  4 A- 4 G show yet another embodiment of the apparatus and the associated process steps;  
         [0013]    FIGS.  5 - 7  show an alternate embodiment of a mandrel;  
         [0014]    FIGS.  8 A- 8 F show the apparatus and process steps incorporating the mandrel of FIGS.  5 - 7 ; and  
         [0015]    FIGS.  9 - 20  show various end edges which can be created with the disclosed method and apparatus. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0016]    With reference first to FIGS.  1 A- 1 F, the length control process will be described diagrammatically. It should be understood that in each of the FIGS.  1 A- 1 F, the dashed line is the longitudinal center line, with only one-half of the tubular member being shown.  
         [0017]    With reference first to FIG. 1A, a tubular member such as  10  is shown, which would be held in a spinning machine, as hereafter described and spun about a longitudinal axis  12 . A roller such as  14  is movable transversely of the longitudinal axis  12 , as well as along any other longitudinal axis, which is parallel to axis  12 . As shown in FIG. 1B, roller  14 , as it moves transversely and laterally, moves and forms tubular member  10  to have a radiused portion  10 A. As shown in FIG. 1C, a mandrel is shown at  16  having a first end  18  of a constant diameter. A shoulder is formed at  20  as will be described. With respect still to FIG. 1C, as described above, as the tubular member  10  is spun, a jagged or discontinuous end edge is formed, and is shown at  22  in FIG. 1C.  
         [0018]    As shown in FIG. 1D, mandrel  16  is shown with first end  18  extending into the tubular member, with shoulder  20  positioned adjacent to jagged edge  22 . As shown in phantom in FIG. 1D, the roller continues to process the contour of the tubular member  10  to the desired shape. As shown in FIG. 1E, once the tubular member is near its end configuration, roller  14  may now continue to move from left to right as viewed in FIG. 1E by pressing the material intermediate the roller  14  and the mandrel first end  18 . This pressure, and the entrapment between the mandrel  18 , causes a flow forming of the material, such that the material bulges or is formed into a wave as shown in FIG. 1E as  24 . This causes an elongation of the material, such that the material flow forms until it abuts shoulder  20 , as shown in the final position  1 F, whereby the material is flow formed into a constant shoulder, thereby providing a constant thickness end and length to the material and tubular member  10 .  
         [0019]    Advantageously, the mandrel  16  and the mechanism for holding and spinning the material can be provided in the same apparatus, therefore, the longitudinal registration between the two is correlated, such that the longitudinal length of the end device can be fixed in one apparatus.  
         [0020]    With respect now to FIG. 2A, an apparatus is shown at  50  and is generally comprised of a spinning chuck at  52 , a roller mechanism  54 , and a mandrel portion at  56 . It should be understood that the mandrel  56  forms the length-controlled tooling, which is attached to the primary axis tail stock of the spinning machine. As shown in FIG. 2A, the spinning chuck  52  is generally comprised of a plurality of chuck jaws, such as  58 , which are movable radially inward and outward so as to retain tubular member  10  therein. As shown in FIG. 2B, mandrel  56  is comprised of a first end portion  60  having a diameter d 1  and a lead-in section at  62 . The first end portion  60  has a constant diameter which extends rearwardly to a shoulder section at  64 .  
         [0021]    With the apparatus as described in FIGS. 2A and 2B, the process will be described with respect to FIGS. 2C to  2 F. As shown first in FIG. 2C, roller  54  is movable in a transverse direction toward tubular member  10 , such that a tapered section  10   a  is formed in tubular member  10 . Mandrel  56  is now movable toward tubular member  10  to the position shown in FIG. 2C, where the first end  60  of mandrel  56  is positioned within the tapered section  10   a  of tubular member  10 . As shown in FIG. 2C, tube end or land  10   b  is substantially parallel with first end  60  of mandrel  56  and is supported by the mandrel first end. As shown in FIG. 2D, the roller  54  is now projected into the tubular member  10 , to create a transition section  10   c , and causing an enlargement or elongation of land area  10   b . As shown in FIGS. 2D and 2E, as the roller continues to spin land  10   b , from the position shown in FIG. 2D to the position shown in FIG. 2E, the spinning flow forms the material of land  10   b  into shoulder  64  (FIG. 2B), as best shown in FIG. 2E. If necessary, the roller  56  can be moved in an opposite sense as shown, to smooth out the transition sections  10   a  and  10   c , as shown in FIG. 2F to form a modified transition section  10   d . As mentioned above, as chuck  52  and mandrel  56  are incorporated into the same spinning apparatus, the longitudinal registration between chuck  52  and mandrel  56  can be monitored and held in registration, such that the length of tube  10  can be controlled.  
         [0022]    With reference now to FIGS. 3A and 3B, an alternate mandrel is shown at  156  having a first end at  160 , with a tapered end portion at  162 . A frusto-conical section  166  is positioned rearwardly of first end  160 , such that a front end of the frusto-conical portion  166  forms shoulder  164 . The frusto-conical portion  166  further comprises a conical surface  168 , having a first diameter or radial portion at  170  and a second and enlarged diameter or radial portion at  172 . In the embodiment shown in FIG. 3B, the radial portion  172  is slightly smaller than the diameter of tubular member  10 . Mandrel  156  is moved towards tubular member  10 , such that conical surface  168  is positioned within an end of the tubular member  10 . Roller  54  is now moved towards tubular member  10  and is moved in a direction inwardly and towards the chuck  52 , as shown in FIG. 3C, such that a portion  10   c  of the tube is pressed against, and conforms to, the conical surface  168 . This also forms another reduced diameter section at  10   d  integral with the remainder of tubular member  10 .  
         [0023]    With respect now to FIGS. 3D and 3E, roller  54  now takes deep passes, first from right to left as in FIG. 3D, to define transition section  10   e , and then from left to right as shown in FIG. 3E, to define a near complete configuration of the transition section as  10   f . When in the position of FIG. 3E, the mandrel  156  is moved to the right, to the position shown in FIG. 3F, and a transition section  10   g  is formed, together with land  10   h , which lies adjacent to mandrel portion  160 . When in this position, the roller can thereafter move in the opposite direction, that is, from left to right as viewed in FIG. 3G and flow form the material of land  10   h  into shoulder  164 , as shown in FIG. 3H. Any further transitional changes can also be formed, such as the process step according to FIG. 3I forming transition section  10   i . Advantageously, the process according to FIGS.  3 A- 3 I causes less distortion of the end edges, due to the movement of the roller  54  from right to left in the process step according to FIG. 3B and therefore reduces the overall process time of the production of the tubular member from the configuration of FIG. 3A to the configuration of FIG. 3C.  
         [0024]    With reference now to FIG. 4A, another tubular member can be assembled, whereby an inner tubular member  200  can be positioned co-axially to tubular member  110  and held in place at one end by a baffle plate, such as  202 . As shown in FIGS. 4B and 4C, roller  54  can be moved inwardly and transversely of the tube  110 , to form the end of tubular member  110  into a reduced diameter section  10   b , and having a land section  110   c , which conforms to the diameter of inner tubular member  200 . As shown best in FIG. 4G, the front shoulder  64  is undercut at  66 , as will be described herein. When the tube  110  and inner tube  200  are in the position shown in FIG. 4C, mandrel  56  can be moved to the left as shown in FIG. 4D, such that the first end portion  60  of mandrel  56  is positioned within the inner tubular member  200 , with the inner tubular member  200  fitting within undercut section  66 . The mandrel can also help define in this embodiment, the longitudinal position of the inner tube  200 . The tube  200  is positioned within the baffle  202  in an interference fit. The end of the mandrel  60  is also insertable into the end of the tube  200  in an interference fit; but the force to insert the mandrel  56  into the inner tube  200  is less than the force to move the inner tube longitudinally within the baffle  200 . The mandrel  56  is also designed to provide enough force to overcome the interference fit between the inner tube and the baffle  202 , and thus the mandrel and tail stock are able to longitudinally position the inner tube  200  properly within the baffle  202 . As shown in FIG. 4C, inner tube  200  extends beyond baffle  202  by a distance x 1 , whereas when in the position of FIG. 4D, the tube  200  has been pushed through the baffle  202  by the mandrel, so that it now extends through by a length of x 2 .  
         [0025]    With mandrel  56  as shown in FIG. 4D, the roller  54  is urged into reduced diameter section  110   b  to create transition section  110   d . The end  110   c  can then be flow formed as described above, from the position shown in FIG. 4D to a position shown in FIG. 4E, such that the end edges of section  110   c  abut shoulder  64 . Due to undercut  66 , inner tube  66  protrudes somewhat from the end of tube end  110   c . The tube  110  can thereafter be finished by successive passes of the roller  54  to form the end transition profile  110   e , as shown in FIG. 4F. Also due to the uneven ends of the inner tube  200  and end  100   c , the two ends can be easily welded together, to form the finished product.  
         [0026]    With respect now to FIGS.  5 - 7 , a further mandrel is shown at  256 , generally comprised of a frusto-conical section  258  and a mandrel end section  260 , where the mandrel end section  260  and frusto-conical section  258  are movable longitudinally relative to each other. Frusto-conical section  258  includes a front end section  264  forming a shoulder, an inclined section  266 , which extends from a radial dimension at  268  to a radial dimension at  270 . The frusto-conical section  258  further includes an inner bore at  272  for receiving the movable front end portion at  260 , as described further herein.  
         [0027]    With respect still to FIG. 5, the mandrel end section  260  is comprised of a central movable pin member  280  comprised of a central rod  282  having a front head section  284 , and an outer member  286 . The outer member  286  includes a first diametrical section at  290  having a shoulder at  292  and a second diametrical portion at  294 . The outer member  286  further includes an inner bore at  296  to receive pin section  282  therein. As shown, the pin portion  280  and outer member  286  are linked together by way of toggle links  298  and  299 . As shown in FIG. 6, the frusto-conical section  258  and mandrel end section  260  are movable longitudinally to a position where diametrical portion  294  (FIG. 5) is positioned within bore  272 . It should be noted that in this position, shoulders  264  and  292  are longitudinally aligned; however, the mandrel can be designed so as to form an undercut section, similar to that described above in relation to undercut  66 .  
         [0028]    Finally, as shown in FIG. 7, the central pin portion  280  is movable longitudinally to the mandrel end portion  260  to a position where the outer profile of the toggle links are equal to or less than the profile defined by diameter portion  290 . Section  286  includes an inner base at  274  forming an inner shoulder. Pin member  282  is also threaded at an end thereof to receive lock nuts  275 , trapping a compression spring  276  therebetween. This spring loads the pin member  280  in the normally closed position of FIG. 5. Link  277  is pinned to member  286  and toggles between an end of pin member  282 , and an end surface  278  of frusto-conical member. Thus, when frusto-conical member  258  retracts to the position shown in FIG. 7, pin member  282  is pushed outwardly of the member  286 , thereby lowering the toggle links  298 ,  299 .  
         [0029]    With respect now to FIGS.  8 A- 8 F, a catalytic converter  300  can be assembled with the use of mandrel  256  of FIGS.  5 - 7 , which includes outer tube  310 , monolith substrates  312 , and heat shields  314 . As shown in FIG. 8A, the tube  310  can be held in place by chuck  50 , with monoliths  312  positioned within tube  310 . As shown best in FIG. 8B, heat shield  314  is held in place on mandrel  256 , where annular flange  316  of heat shield  314  is positioned on diameter portion  290  (FIG. 5) and abuts shoulder  292 . With the center pin portion  280  retracted, toggle links  298  and  299  retain funnel-shaped section  318 , as shown in FIG. 8B. Mandrel  256  is integrated with tail stock member  400  (FIG. 8A), which is movable on a top surface  402  of platen  404 .  
         [0030]    Thus, to position the heat shield  314  within tube member  310 , tail stock member  400  is moved to the left, as shown in FIG. 8B, to position the heat shield member  314  against the outer monolith substrate  312 , as shown in FIG. 8C. With the heat shield positioned therein as shown, the spinning process can begin to produce a reduced diameter section  310   a  and land  310   b . The mandrel can now be positioned in the configuration previously described with relation to FIG. 6 to position shoulder  264  co-aligned with the end of heat shield annular flange  316 . Roller  54  first forms transition section  310   c , as shown in FIG. 8D. The flow forming of tubular member  310   b  is now performed, as shown in FIG. 8D, such that the length of the annular portion  310   b  is the identical length as annular flange  316  of heat shield  318  and forms a square abutment therewith. The roller  54  moves, and flow forms the material of section  310   b , from the position of FIG. 8D to the position of FIG. 8E. The roller is thereafter moved towards the chuck, as shown in FIG. 8F, to form a consistent transition section  310   d . As mentioned above, the end face  264  can overlap shoulder  292 , to create an undercut, similar to  66  described above, such that the finished product has annular flange  316  protruding slightly beyond finished end  310   b . This allows for easier welding of the two ends.  
         [0031]    With respect now to FIGS.  9 - 20 , various end edges can be created by the disclosed method and apparatus, whereby any of the shoulders  20 ,  64 ,  164  or  264  can include the configuration to define the end edges. With respect first to FIGS. 9 and 10, one of the shoulders could include a profile to define interdigitated raised portions, such as  400 , such that the shoulder portions would include counterpart portions to define the recessed edges, for example at  402 . Similarly, the mandrel shoulders could include a recessed notch so as to define a nib, such as  410 , as shown in FIGS. 11 and 12. As shown in FIGS. 13 and 14, the mandrel shoulders could include a profile so as to define castellated portions  420 . Also with respect to FIGS. 15 and 16, the mandrel shoulders could include recesses and dimples so as to define counterpart dimples  430  and recesses  432 . As shown in FIGS. 17 and 18, the shoulder could also include raised text  440  so as to define text  440  recessed into the end face of the finished work product.  
         [0032]    With respect now to FIGS. 19 and 20, an alternate mandrel  356  is shown having a forward end section  358  and a forwardly facing shoulder  360 . Intermediate the sections  358  and  360  are defined counterpart threaded sections  362  so as to define threaded section  450 .  
         [0033]    As should be appreciated, once the spinning process is complete, to the configuration of FIG. 8F, the central pin portion  280  of the mandrel is moved to the configuration of FIG. 7, such that the toggle links collapse and the entire mandrel portion, including the outer portion  260  and the central pin portion  280 , can be retracted by way of reversing the tail stock  400 , which slides the entire mandrel out of the completed end. The partially completed catalytic converter  310  can now be reversed, with the completed end positioned within the chucks, and another heat shield can be positioned in the unfinished end of the catalytic converter  310 , as just described.