Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3643485 A
Publication typeGrant
Publication dateFeb 22, 1972
Filing dateDec 15, 1969
Priority dateMay 5, 1966
Also published asDE1602331A1, DE1602332A1, US3503238
Publication numberUS 3643485 A, US 3643485A, US-A-3643485, US3643485 A, US3643485A
InventorsMarcovitch Jacob
Original AssigneeRotary Profile Anstalt
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High-pressure rolling of workpieces
US 3643485 A
Abstract
A die for drawing tubular workpieces has its orifice defined by a ring of small rollers which are rotatable to work the workpieces around their circumference. Means may be present to straighten the tube and the die may include means to make the wall thickness of the workpiece uniform.
Images(5)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

111111111116 @tmtes Mare/11171 1116111 1 Feb, 22, 11972 [54] lHlllGlHI-lilRlEfifilUllklE RUILILHNG 60 1' 1,596,751 8/1926 Millspaugh ..72/126 X W/URKPMEQES 1,665,915 4/1928 Ekman 1 1 1 ..72/126 X 2,375,108 5/1945 Hopkins ..72/126 [72] Inventor: ,lacob Marcovitch, Johannesburg, Republic 2 07 971 10/1957 Gamer et 1 72 9 OfSourh Africa 3,387,477 6/1968 Shupper ..72/126 11 3,473,358 10/1969 Marcovitch 1 ..72/126 X [73] Assgnee' fig? Ammm Vaduz Llechte 1,184,972 5/1916 Lloyd 1 ..72/126 1,530,381 3/1925 Leedom ..72/126 [22] Filed: Dec. 115, 1969 1,774,231 8/1930 Harnsberger ..72/126 X 1,970,061 8/1934 Stanfield et al. ..72/126 [21] flmjm 2,383,214 8/1945 Prout ..72/126 x R E Red U-S'A a D t 2,522,257 9/1950 Curtis 1 ..72/126 e a W a m 2,546,756 3/1951 KI'IOWHCOH ..72/126 1 Continuation of N 7, l y 1 aban- 3,160,036 12/1964 Ernestus ..72/110 )4 doned. 3,449,812 6/1969 Hauschke et a] ..72/126 X [30] Foreign Application Priority 1 am Primary Examiner-Milton S. Mehr May 5, 1966 Republic 616611111 A1ric11.....66/26|0 MOWPYOUY'E Tlmmpw Aug. 17, 1966 Republic ofSouth Africa. .66/f1 911 [52] 11.5. C1 72/16, 72/87, 7722711205, [57] MEMWACT [51] int. Cl. ..lElZllb 19/03, 1321b 3/06 A die for drawing tubular workpieces has its orifice defined by [58] lFielrli of Search ....72/113, 1 12, 1 10, 107, 102, a ring of small rollers which are rotatable to work the work 72/98, 126, 96, 100, 87, 194, 191 pieces around their circumference. Means may be present to straighten the tube and the die may include means to make the [56] lRellerenees lCi/tetll wall thickness of the workpiece uniform.

UNITED STATES PATENTS 27 Claims, 15 Drawing Figures 447,582 3/1891 Robertson ..72/96 1,072,001 9/1913 Haas PATENIEBFEBZQ m2 31.8% ,ABB

swan M nr 5 IIIGl'rlI-IPItlESSIJIklE ROLLING F WGIIKIIIIPIIEQES This application is a continuation of application Ser. No. 634,947, filed May I, l967 and now abandoned.

This invention relates to the treatment of tubular workpieces, by which is meant operating on them to produce a tube of uniform outer or inner diameter, or both, or of uniform wall thickness.

The object of the invention is to provide apparatus which permits tube to be produced to a high standard of precision which is not attainable by conventional techniques, and at a cost which compares favorably with the cost of such techniques.

Conventional methods employ dies through which the material is drawn or extruded. Apart from inaccuracy due to die wear, there is always the problem of maintaining the core of the die in correct alignment with the shell. Without such alignment, wall thickness cannot be controlled, and it is common experience that wall thickness can vary by as much as 20 percent in commercial tubing.

To avoid these difficulties and defects, the present invention makes use of the concept of subjecting the tube to a rolling operation, internally or externally, carried out by a series of small rollers arranged to rotate and to profile the tube as they roll in line contact with it, by applying progressively around the circumference of the tube pressure over a very small area, so that the intensity of pressure is very high.

According to the invention, apparatus to put this concept into practical effect consists, broadly, of a die through which the tubular workpiece is adapted to be drawn, the die orifice being, at least partly, defined by a ring of small rollers; means to cause rotation of the rollers around the circumference of a workpiece in the orifice, and means to pass the workpiece through the orifice. The circumference may be the external or the internal circumference.

Further according to the invention, the rollers are individually skewed" to the axis of the orifice, so that, as they turn, they tend to draw the workpiece through the throat. The transport of the workpiece may be achieved solely by this means, or axial force may be applied externally to the workpiece.

Also according to the invention, the die includes a series of rings of rollers, spaced apart along the length of the orifice, to reduce the effective diameter of the orifice, so that the workpiece is progressively treated as it advances through the orifice.

Several embodiments of the invention are illustrated in the accompanying drawings, in which:

FIG. I is a vertical section through one from of die,

FIG. 2 is a fragmentary view, in section, of a form of die in which the rollers are arranged to skew.

FIG. 3 is a similar view of another embodiment in which the rollers are mounted on stub axles,

FIG. 4 is a similar view, showing rollers that are pinned in a holder,

FIG. 5 is a similar view of rollers mounted in a cage,

FIG. 6 is an end view showing the rollers backed by other rollers,

FIG. '7 is a fragmentary view showing the arrangement of FIG. 6 in detail,

FIG. 8 is a fragmentary end view partly in section showing a tubular workpiece being internally worked,

FIG. 9 is a section on the line 9-9 of FIG. d,

FIG. III is an end view of another embodiment for internal working of a tube,

FIG. Ill is a side view of the preferred form of roller,

FIG. I2 is a fragmentary vertical section showing a means to straighten as well as work a tube internally,

FIG. I3 is a vertical section through a machine for internally treating a tube to obtain a uniform wall thickness,

FIG. 14!- is a similar view, but showing a tube being externally treated for the same purpose, and

FIG. 15 is an end view showing a tube being treated simultaneously, internally and externally.

In FIG. I, the die consists of a body III having an orifice I2 that is stepped. Inside the orifice is a series of spaced grooves MI, each of which constitutes a race for a series of small rollers 16 which line the orifice to provide the throat through which a tubular workpiece lid is drawn. For the required relative rotation between the tube 113 and rollers I6, the body III may be rotated, or the tube llfi may be rotated as it is passed through the throat.

Each roller I6 is convex in profile. If the rollers are square on to the tube, external means must be provided to draw the tube through the throat. Any means suitable for this purpose may be used, for instance a chuck which: grips the leading end of the tube, or a capstan around which the tube is coiled. However, it is preferable to arrange the rollers so that they act to draw the tube through the die, or at least assist in doing so. To this end, the rollers are arranged obliquely to the axis of the throat, so that they form a sort of Archimedean screw to drive the tube. This arrangement is described later.

It will, of course, be appreciated that, for a small reduction of diameter, or for soft material, it may not be necessary to provide several rings of rollers: one ring may be sufficient.

In FIGS. I and 2, the rollers are arranged to roll on the floor of the channels M. In FIG. 3, each roller is provided with stub axles 241) that roll on the lands 22 of the grooves.

The rollers may be free within the grooves in the sense that they are held in the grooves only by the: presence of the tube Id. In some cases, this may be disadvantageous since, when the throat is empty, the rollers will fall out of it. Accordingly, in FIGS. I and 5, the rollers are held positively within the grooves, in FIG. d by being mounted on pins 2d that are journaled within holes in the sidewalls of the grooves, and in FIG. 5 by being mounted within cages 26 with which stub axles 23 on the rollers are engaged.

In FIGS. 6 and i, the rollers I6 are backed by rollers 30 which have stub axles 32 that are joumaled in the sidewalls of the groove 34. The rollers 30 are circumferentially grooved at 36, and the groove serves as a guide for the roller I16. As will be seen in FIG. 6, the series of rollers I6 is intercalated with the series of rollers 30, so that each roller I6 is backed by two rollers 30.

In FIGS. 4i, 5, b and 7, the rollers may be permanently kept in a skewed position by skewing their mountings.

Thus far, the embodiments described concern the profiling of the outer surface of tubular workpieces, to provide a uniform outer diameter and a good finish. If the wall thickness of the tube is not uniform, it remains so. In the embodiments that are illustrated in FIGS. ll, 9, It) and I2, it is the inner surface of the tubular workpiece that is treated.

In FIGS. 8 and 9, the tubular workpiece 3% is caused to travel axially through a throat defined between juxtaposed rollers 10 that rotate about fixed axes. Inside the throat, and within the cavity of the tube is a rod I2 coaxial with the tube, surrounded by a tubular holder 44 slotted to accommodate rotatably a series of rollers 416 which rotate about their axes, which are kept in a fixed position relative to the rollers 4M), as shown in FIG, d, by the holder Ml.

In operation, the tube 3% is offered to the throat and is drawn or propelled through it. The rollers III, or one or two of them, is or are rotated, which imposes rotation on the tube 3%. The rod 412 is simultaneously rotated in the opposite direction. This causes the rollers do to rotate. As the tube advances between the rollers as and the rollers ill, a uniform internal diameter is imposed on it by the rollers M6, the tube being buttressed by the rollers II This operation sizes the internal and external diameters simultaneously. Preferably, the tube is initially slightly undersize in these diameters.

Tubes in their raw state are almost invariably bent, especially when they come in long lengths. The arrangement of FIG. I2 is intended to be of use in straightening them and slightly elongating them. The raw tube 3% is traversed past a multiroller system, which may be large rollers as shown at li) in the top part of the figure, or a series of needle rollers 56 as seen in the lower part. Within the traversing tube It is an assembly of rollers 48, 50 which may be skew mounted, in advance of which is a plunger 52 and to the rear of which is a second plunger 53 of somewhat greater diameter. The assembly is rotated by a stem 4:2 fast with the rear plunger 53, the rotation being transmitted to the inner rollers 68, 50 and the front plunger through the stem 42 around which the inner rollers 48, 50 revolve.

The tube 38 is drawn through the throat between the inner rollers and the outer rollers. The front plunger 52 is a sliding fit within the tube cavity. The inner rollers reduce the wall thickness while straightening the tube, and the rear plunger 53 is a sliding fit within the increased internal diameter of the tube. For the sake of clarity, this increase has not been illustrated in FIG. 12.

Pressure oil may be fed to the outer surfaces of the plungers 52, 53, through a bore 55 in the stem 42 and through grooves 57 in the plungers in communication with the bore 55.

In FIG. 10, an arrangement such as in FIGS. 8 and 9 is shown, but in place of a few inner rollers there is a large number of needle rollers 54 between the inner surface of the tube 38 and the outer surface of a core 56. The rollers 54 are constrained against endwise movement by engagement in grooves in the core 56 but need not otherwise be constrained, as they are held in position by the tube. There are sufficient rollers 54 to line completely the throat defined between the tube and the core.

In FIG. 15, the same system of needle rollers 54 is seen, but the outer rollers 40 give place to a large number of needle rollers 58 which surround the tube and which are contained within the bore of a hollow, cylindrical holder 60. The rollers, 58, like the rollers 54, are confined against axial movement by being located within annular grooves in the holder 60, but need not otherwise be constrained. As the throat is defined between two sets of rollers that are buttressed against radial displacement, so that the throat is and remains uniform, passage of the tube 38 through the throat imposes on the tube prescribed inner and outer diameters.

In FIGS. 13 and 14, embodiments are shown which produce concentric, straight tubes from commercial tubing which, as is usual, is both eccentrically apertured and bent. In FIG. 13, a tube 62, which has been sized as to outer diameter by the apparatus or otherwise, is placed within a housing 64 having a bore 66 in which the tube is a close fit. The bore 66 is, at 68, reduced to the exact diameter to which it is desired to bring the inner diameter of the tube. A number of rollers 70, arranged for orbiting in a circle, which is exactly the diameter of the reduced bore of the housing, is mounted on a mandrel 72 which is a sliding fit in the reduced bore 68 and which projects into the bore 66 to define therewith an annular passage. The rollers 70 are passed through the reduced bore by advancing the mandrel 72, which is simultaneously rotated, by means such as a belt 74 which engages a pulley 76 slidably mounted on a splined stem 78 projecting rearwardly from the mandrel 72. As the rollers 70 advance into and through the tube, they orbit and roll out any eccentricity in the bore of the tube, which is removed from the machine straight, with uniform wall thickness, and well-finished internally. The strength of the tube will be enhanced by the rolling operation.

In FIG. 14, the tube 80 is first finished as to its inner diameter, either by the means of the invention or otherwise. Thereafter, it is impaled upon a mandrel 82 and inserted into an annular passage defined by the mandrel 82 and an enlarged bore or counterbore 88 of a cylindrical housing 86. The mandrel 82 has a shoulder 84 against which the end of the tube abuts, and which marks the division between the length of mandrel that enters the tube and a part of diameter exactly equal to that to which the outer diameter of the tube is to be brought. This larger diameter is used as a guide over which slidably passes a cylindrical housing 86 that carries, with a counterbore 88, a series of small rollers 90 which orbit the tube, and define a circle of exactly the diameter to which the tube is to be brought. The housing is caused to traverse the tube and at the same time is rotated by means such as a gear wheel 92 that engages teeth 94 on the periphery of the casing. The gear wheel 92 is rotated through a shaft 96 driven by a belt 98 passing around a pulley 100 on the shaft. Rotation of the housing causes the rollers to orbit around the tube and to profile the tube between themselves and the mandrel 82 to the prescribed outer diameter, at the same time rolling out eccentricities in the bore to produce a uniform wall thickness.

The mandrel in FIG. 14, or the bore 66 in FIG. 13 might, of course, be profiled such as by splines or other formations to produce a complementally profiled surface in the finished tube.

The shape of the rollers that impose the profile upon the workpiece is, in all embodiments of the invention, of importance. A convex or barrel shape is essential for internal profiling. The best form of roller is illustrated in FIG. ll, in which it will be seen that the convexity consists of an annular swage 102 at the middle of the roller. For external rolling, the rollers may be convex, cylindrical or even concave if the rollers are obliquely mounted.

The rollers may be obliquely mounted to promote travel of the tube relatively past them, or it may be desirable that the rollers be so mounted that they take up their own orientation as the operation proceeds. To this end, the rollers may be floatably mounted as in FIG. 2, in the sense that they are permitted a measure of play which permits them to swivel to balance the forces acting on them.

It will be observed that in all embodiments the rollers are backed either longitudinally or at both their ends against thrust from the workpiece. This allows high-pressure intensity to be exerted over a small area of the workpiece while the rollers are fully supported, and a large force may be applied to urge them towards the workpiece.

I claim:

1. Apparatus for rolling a tubular workpiece comprising structure defining an annular throat and within the throat an annular series of nonspherical rollers, each of which has its center portion of greater diameter than the diameter of its axially outer portions, said throat comprising at least one backing member having a surface which is a surface of revolution on which surface at least said outer portions of the rollers roll in line contact, whereby in use a tubular workpiece passing through the throat with relative rotation between the workpiece and the rollers about the axis of the workpiece undergoes deformation of a surface thereof.

2. The apparatus of claim 1 further comprising means for causing relative rotation between the rollers and a workpiece.

3. The apparatus of claim 1 further comprising means for advancing the workpiece through the throat.

4. The apparatus of claim 1 wherein the rollers are arranged so as in use to act on the outside of the workpiece.

5. Apparatus as claimed in claim 4, and a mandrel located within the throat to support the inside surface of the workpiece.

6. Apparatus as claimed in claim 5, in which the surface of said mandrel is contoured.

7. The apparatus of claim ll wherein the rollers are arranged so as in use to act on the inside of the workpiece.

8. Apparatus as claimed in claim 7, in which the throatdefining structure is contoured.

9. The apparatus of claim 1 wherein the rollers are arranged with their axes substantially parallel with the axis of the throat.

10. The apparatus of claim 1 in which the rollers are arranged with their axes oblique relative to the axis of the throat.

11. The apparatus of claim 1 including a number of annular series of rollers spaced apart along the length of the throat.

12. The apparatus of claim 111 in which the diameters of the circles encompassed respectively by the series of rollers decrease along the length of the throat.

13. The apparatus of claim I in which the backing member is formed with an annular groove for said series of rollers.

14. The apparatus of claim 13 in which the backing member is bored to provide the throat and said groove is provided within the wall of the bore.

iii. The apparatus of claim 7 in which the backing member is a stem adapted to enter the workpiece.

lid. The apparatus of claim 1155 in which the structure is a housing with a cylindrical aperture which encloses the workpiece.

ll. The apparatus of claim id in which the structure is a se ries of rollers parallel with and mounted around the workpiece.

lb. The apparatus of claim lid in which the backing member is bored to the outer diameter to which the workpiece is to be brought and is counterbored to receive the rollers.

l9. Apparatus for treating a hollow workpiece, comprising first and second means defining between them an annular aperture and an annular series of rollers in the aperture, said first means including at least one backing member having a surface which is a surface of revolution on which surface at least the axially outer portions of the rollers are supported in line contact, the workpiece and said first means being axially and rotatively movable relative to each other to cause the rollers to traverse a periphery of the workpiece, said rollers being freely supported on said backing member for orbital movement about said backing member whereby upon rotative movement of said first means and workpiece relative to each other, the line of contact between each roller and the backing member rotates about the periphery of the backing member and a surface of the workpiece undergoes deformation.

Lilli). Apparatus as claimed in claim 19, said rollers being elongated in their axial direction and having a center portion which contacts the workpiece and is of greater diameter than the endwise outer portions of the rollers which do not contact the workpiece, the total length of said line of contact between said backing member and the rollers being greater than the length of said center portion which contacts the workpiece.

21. Apparatus as claimed in claim lit, in which said hacking member comprises a mandrel that extends into the workpiece to cause the rollers to act on the inner surface of the workpiece, said second means comprising an elongated circumferentially continuous wall that acts on the outer surface of the workpiece.

22. Apparatus as claimed in claim ill, in which the mandrel is of a diameter equal to that required of the workpiece, the mandrel having a sliding lit in an elongated bore coaxial with the circumferentially continuous wall and formed in a rigid housing.

23. Apparatus as claimed in claim Ml, in which each of the rollers has stub axles on opposite axial ends of said center portion, the stub axles of each roller having a combined axial length greater than that of said center portion, at least the stub axles of the rollers being supported in line contact on said backing member.

M. A method of rolling a workpiece having at least one surface which is a surface of revolution, the method comprising:

a. rolling the said surface at high pressure by the median portion of each of a plurality of rollers, each roller being arranged with a major component of the direction of its axis parallel to the axis of the said surface of the workpiece,

b. supporting and rolling the portions of each of the said rollers on either axial side of the said median portion in rolling line contact with massive backup means, the axial length of said line contact being greater than the axial length of contact between the workpiece and the said median portions,

c. causing relative movement between the workpiece and the rollers about the axis of the said surface of the workpiece, and

d. causing relative movement between the said workpiece and rollers in the direction of the said axis of the said surface of the workpiece, the arrangement being such that rolling causes considerable metal flow in the workpiece.

29. A method as claimed in claim 2a in which there is no substantial deviation from true rolling between the backup means and the said portions on either side of the median portion of each roller. I

2b. Apparatus for rolling a workpiece having at least one surface which is a surface of revolution, the apparatus comprising:

a. structure defining a throat and being comprised at least partially by a series of rollers, each said roller having a median portion to engage the workpiece and additional portions on either axial side of said median portion, and

b. massive backup means on which the said additional portions are supported and roll in line contact, the axial length of the said line contact being greater than the axial length of said median portion.

2'7. Apparatus as claimed in claim as in which the diameter of the said median portion is greater than the maximum diameter of the said additional portions.

time

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US447582 *Mar 7, 1890Mar 3, 1891 robebtson
US1072001 *Dec 21, 1912Sep 2, 1913Philip M HaasMachine for reducing the section of metal blanks.
US1184972 *Sep 19, 1913May 30, 1916Elyria Iron & Steel CompanyMachine for reducing and surface-finishing metal tubes, rods, and the like.
US1530381 *May 1, 1923Mar 17, 1925Western Union Telegraph CoTube-expanding tool
US1596751 *Oct 24, 1924Aug 17, 1926Sandusky Foundry & Machine CoTube-rolling machine
US1665915 *Dec 21, 1925Apr 10, 1928Ekman Albert CPipe-swaging device
US1774231 *Sep 20, 1927Aug 26, 1930Pure Oil CoMeans for producing heat-transfer conduits
US1970061 *Jan 24, 1933Aug 14, 1934Lynn Kenneth SmithSwage for oil wells
US2375108 *Apr 7, 1944May 1, 1945Kellogg M W CoProcess for conditioning metal ingot molds
US2383214 *May 18, 1943Aug 21, 1945Bessie PugsleyWell casing expander
US2522257 *May 18, 1945Sep 12, 1950Bishop & Babcock Mfg CoMeans for forming tubes from tubular blanks
US2546756 *May 14, 1949Mar 27, 1951Griscom Russell CoTube expander
US2807971 *Feb 5, 1952Oct 1, 1957Rca CorpCold-working process for articles
US3160036 *Aug 29, 1958Dec 8, 1964Lockheed Aircraft CorpRoll-forming mill
US3387477 *Nov 29, 1965Jun 11, 1968Price Pfister Brass MfgApparatus and method for roll forming flexible tubing
US3449812 *Jan 23, 1967Jun 17, 1969Kotthaus & BuschMethod of securing tube end portions in bores of a heavy plate by pilgrim step rolling
US3473358 *Dec 19, 1966Oct 21, 1969Rotary Profile AnstaltProfiling of workpieces that are figures of revolution
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3802240 *Apr 6, 1973Apr 9, 1974Wieland Werke AgDevice for the conical tapering of circular cross sectioned elongated workpieces
US4306437 *Dec 10, 1979Dec 22, 1981Grotnes Metalforming Systems, Inc.System for planishing metal pipe
US4919870 *Dec 15, 1987Apr 24, 1990Ibar Jean PierreProcess of and apparatus for treating a shaped product
US5306129 *May 11, 1992Apr 26, 1994Solomat Partners, L.P.Molding deformable materials with use of vibrating wall surfaces
US5494426 *Feb 17, 1994Feb 27, 1996Thermold Partners L.P.Vibrating wall surfaces for molding deformable materials
US5650104 *Jun 6, 1995Jul 22, 1997Thermold Partners L.P.Molding deformable materials with use of vibrating wall surfaces
US7575060 *Jul 11, 2003Aug 18, 2009Weatherford/Lamb, Inc.Collapse resistance of tubing
US7591164Sep 8, 2005Sep 22, 2009Dana Automotive Systems Group, LlcMethod of manufacturing a splined member for use in a driveshaft assembly
US7975519 *Jul 12, 2011Tooman Norman LWind turbine installation comprising an apparatus for protection of anchor bolts and method
US8117883Mar 5, 2010Feb 21, 2012Weatherford/Lamb, Inc.Tubing expansion
US8746028Mar 25, 2004Jun 10, 2014Weatherford/Lamb, Inc.Tubing expansion
US20040055756 *Jul 11, 2003Mar 25, 2004Hillis David JohnCollapse resistance of tubing
US20040216506 *Mar 25, 2004Nov 4, 2004Simpson Neil Andrew AbercrombieTubing expansion
US20060048556 *Sep 8, 2005Mar 9, 2006Duggan James AMethod of manufacturing a splined member for use in a driveshaft assembly
US20100218582 *Sep 2, 2010Weatherford/Lamb, Inc.Tubing expansion
EP0955110A2 *Jan 27, 1999Nov 10, 1999Leico GmbH & Co. WerkzeugmaschinenbauMethod and device for flow-turning
Classifications
U.S. Classification72/96, 72/126, 72/110, 72/87
International ClassificationB21B1/16, B21B23/00, B21H1/06, B21C1/26, B21B19/00, B21H1/18, B21K1/00, B21B19/12, B23D25/00, B21H1/00, B21C1/16, B21C3/00, B23D25/04, B21C3/08, B21H8/00, B21K1/76
Cooperative ClassificationB21C3/08, B21H8/00, B21B19/12, B21C1/26, B21H1/06, B21H1/18, B21K1/761, B21B1/16, B23D25/04, B21B23/00
European ClassificationB21H8/00, B23D25/04, B21H1/06, B21C3/08, B21K1/76B, B21B23/00, B21B19/12, B21C1/26, B21B1/16, B21H1/18