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.

For example, in U. S. Patent 6,536, 315, a method of spinning a material to a circumferential configuration having a constant length is shown. The method comprises the steps of providing a tubular material to be spun; providing a tooling roller and moving it tangentially towards the material; causing relative rotational movement between the roller and the material; and moving the roller along an axis parallel to the longitudinal axis, thereby spinning the material to a radially different configuration.

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.

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 method comprises the steps of providing a tubular material to be spun; providing a tooling roller and moving it tangentially towards the material; causing relative rotational movement between the roller and the material; and

moving the roller 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.

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.

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.

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.

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.

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.

Figures 1A-1F show diagrammatically a spinning process including the provision of a mandrel to form the spun end with a constant longitudinal length; Figures 2A-2F show an apparatus and process steps substantially according to the process shown in Figures 1A-1F ; Figures 3A-3I show a further embodiment of the apparatus and the associated process steps; Figures 4A-4G show yet another embodiment of the apparatus and the associated process steps; Figures 5-7 show an alternate embodiment of a mandrel;

Figures 8A-8F show the apparatus and process steps incorporating the mandrel of Figures 5-7; and Figures 9-20 show various end edges which can be created with the disclosed method and apparatus.

With reference first to Figures lA-1F, the length control process will be described diagrammatically. It should be understood that in each of the Figures lA-1F, the dashed line is the longitudinal center line, with only one-half of the tubular member being shown.

With reference first to Figure 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 Figure 1B, roller 14, as it moves transversely and laterally, moves and forms tubular member 10 to have a radiused portion 10A. As shown in Figure 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 Figure 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 Figure 1C.

As shown in Figure 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 Figure 1D, the roller continues to process the contour of the tubular member 10 to the desired shape. As shown in Figure IE, once the tubular member is near its end configuration, roller 14 may now continue to move from left to right as viewed in Figure 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 Figure 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 IF, 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.

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.

With respect now to Figure 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 Figure 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 Figure 2B, mandrel 56 is comprised of a first end portion 60 having a diameter dl 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.

With the apparatus as described in Figures 2A and 2B, the process will be described with respect to Figures 2C to 2F. As shown first in Figure 2C, roller 54 is movable in a transverse direction toward tubular member 10, such that a tapered section 10a is formed in tubular member 10. Mandrel 56 is now movable toward tubular member 10 to the position shown in Figure 2C, where the first end 60 of mandrel 56 is positioned within the tapered section 10a of tubular member 10. As shown in Figure 2C, tube end or land 10b is substantially parallel with first end 60 of mandrel 56 and is supported by the mandrel first end. As shown in Figure 2D, the roller 54 is now projected into the tubular member 10, to create a transition section 10c, and causing an enlargement or elongation of land area lOb. As shown in Figures 2D and 2E, as the roller continues to spin land lOb, from the position shown in Figure 2D to the position shown in Figure 2E, the spinning flow forms the material of land 10b into shoulder 64 (Figure 2B), as best shown in Figure 2E. If necessary, the roller 56 can be moved in an opposite sense as shown, to smooth out the transition sections 10a and 10c, as shown in Figure 2F to form a modified transition section 10d. 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.

With reference now to Figures 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 Figure 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 Figure 3C, such that a portion 10c of the tube is pressed against, and conforms to, the conical surface 168. This also forms another reduced diameter section at 10d integral with the remainder of tubular member 10.

With respect now to Figures 3D and 3E, roller 54 now takes deep passes, first from right to left as in Figure 3D, to define transition section 10e, and then from left to right as shown in Figure 3E, to define a near complete configuration of the transition section as lOf. When in the position of Figure 3E, the mandrel 156 is moved to the right, to the position shown in Figure 3F, and a transition section lOg is formed, together with land 10h, 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 Figure 3G and flow form the material of land 10h into shoulder 164, as shown in Figure 3H. Any further transitional changes can also be formed, such as the process step according to Figure 31 forming transition section 10i. Advantageously, the process according to Figures 3A-3I 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 Figure 3B and therefore reduces the overall process time of the production of the tubular member from the configuration of Figure 3A to the configuration of Figure 3C.

With reference now to Figure 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 Figures 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 110b, and having a

land section 110c, which conforms to the diameter of inner tubular member 200. As shown best in Figure 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 Figure 4C, mandrel 56 can be moved to the left as shown in Figure 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 Figure 4C, inner tube 200 extends beyond baffle 202 by a distance xl, whereas when in the position of Figure 4D, the tube 200 has been pushed through the baffle 202 by the mandrel, so that it now extends through by a length of x2.

With mandrel 56 as shown in Figure 4D, the roller 54 is urged into reduced diameter section 110b to create transition section 110d. The end 110c can then be flow formed as described above, from the position shown in Figure 4D to a position shown in Figure 4E, such that the end edges of section 110c abut shoulder 64. Due to undercut 66, inner tube 66 protrudes somewhat from the end of tube end 110c. The tube 110 can thereafter be finished by successive passes of the roller 54 to form the end transition profile 110e, as shown in Figure 4F. Also due to the uneven ends of the inner tube 200 and end 100c, the two ends can be easily welded together, to form the finished product.

With respect now to Figures 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.

With respect still to Figure 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 Figure 6, the frusto-conical section 258 and mandrel end section 260 are movable longitudinally to a position where diametrical portion 294 (Figure 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.

Finally, as shown in Figure7, 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 Figure 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 Figure 7, pin member 282 is pushed outwardly of the member 286, thereby lowering the toggle links 298,299.

With respect now to Figures 8A-8F, a catalytic converter 300 can be assembled with the use of mandrel 256 of Figures 5-7, which includes outer tube 310, monolith substrates 312, and heat shields 314. As shown in Figure 8A, the tube 310 can be held in place by chuck 50, with monoliths 312 positioned within tube 310. As shown best in Figure 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 (Figure 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 Figure 8B. Mandrel 256 is integrated with tail stock member 400 (Figure 8A), which is movable on a top surface 402 of platen 404.

Thus, to position the heat shield 314 within tube member 310, tail stock member 400 is moved to the left, as shown in Figure 8B, to position the heat shield member 314 against the outer monolith substrate 312, as shown in Figure 8C. With the heat shield positioned therein as shown, the spinning process can begin to produce a reduced diameter section 310a and land 310b. The mandrel can now be positioned in the configuration previously described with relation to Figure 6 to position shoulder 264 co-aligned with the end of heat shield annular flange 316. Roller 54 first forms transition section 310c, as shown in Figure 8D. The flow forming of tubular member 310b is now performed, as shown in Figure 8D, such that the length of the annular portion 310b 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 310b, from the position of Figure 8D to the position of Figure 8E. The roller is thereafter moved towards the chuck, as shown in Figure 8F, to form a consistent transition section 310d. 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 310b. This allows for easier welding of the two ends.

With respect now to Figures 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 Figures 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 Figures 11 and 12. As shown in Figures 13 and 14, the mandrel shoulders could include a profile so as to define castellated portions 420. Also with respect to Figures 15 and 16, the mandrel shoulders could include recesses and dimples so as to define counterpart dimples 430 and recesses 432. As shown in Figures 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.

With respect now to Figures 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.

As should be appreciated, once the spinning process is complete, to the configuration of Figure 8F, the central pin portion 280 of the mandrel is moved to the configuration of Figure 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.