US2103574A - Positively controlled tube bore mandrel for tube forming machines - Google Patents

Description

M N E Dec. 28, 1937 J. B; WINTVERCQRNI POSITIM-ELY' CQNTROLLED TUBE BORE MANDREL FOR TUBE FORMING MACHINES Filed June 12, 1934 2 {r Mmubm Dec. 28, 1937. r J. B.-- WINTERCORN 2,103,574

' POSITIVELY CONTROLLED TUBEBORVE MANDREL FOR TUBE FORMING MACHINES Filed June 12, 1934 6 Sheets-Sheet 3 FIG. 10.

" PIC-Z9.

7 I43 7 a v FIG 20.

Dec. 28,1937. J wmTERCORN 2,103,574

POSITIVELY CONTROLLED TUBE BORE MANDREL FOR TUBE FORMING MACHINES Filed June 12, 1954 6 Sheets-Sheet 4 my IIIVI.

Plaza; F7624.

, IN VEN-TOE 28,1937. J. B. WINTERCORN 2,103,574

POSITIVELY CONTROLLED TUBE BORE MANDREL FOR TUBE FORMING MACHINES Filed June 12, 1934 6 Sheets-Sh et 5 awn .5 $8

mw WE IN VEN "roe Dec. '28, 1937. J. a. WINTERCORN 72,103,574

POSITIVELY CONTROLLED TUBE BORE MANDREL FOR TUBE FORMING MACHINES Fraao.

Filed June 12, 1954 e sheets-sheet e F'IGT3 FIG34.

Patented Dec. 28, 1937 umrso STATES PAT h h t 1,

rosrrrvatr] ENT F C TUBE BORE armour. roa'rona FORMING. moms 7 John 13. WintercormChicago, n1. 5

Application June 12,1934, Serial No. 730,232 1 1 17 Claims,

My invention relates to improvements in all tube forming machines of that class in general in each of which a tube bore mandrel is employed to form the bore of the tube simultaneously'as the usuaLrollers or, die form the outside surface I of the tube, while progressively working upon an appropriate blank from which the tube is produced within the pass of the rollers or die, having as a general-object thepositive control of the tube bore mandrel within the pass throughout the tube forming operation on the blank in each instance, as contrasted with the lack ofpositive control ofthe tubebore mandrel within the pass in these machines inthe past, for the purpose of improving the accuracy of the location of the bore relative to the outside surface of the tube in each instance production costs of thetubes, as compared with these, factors in tube p chines inthe past, and relatesin particular to these improvements as applied to the disk roller machine for helically rolling; seamless tubes, which constitutes the preferred embodiment of my inventiontas 'desciiibedin detail herein. Tube forming machines of "the describedclass in the past were not'provided with means for positively controllin'g the [tu e bore. mandrels within the pass of'therollers or, the die, and the tube bore mandrelin each instance was allowed to freely float" laterally ,within the pass, as well as turn'through a,considerable angle about the longitudinal axis thereof aspermitted by the torsional flexibility of, the connected ,mandrel rod. The latter turning of the tube bore mandrel, I l

was harmful of course only when making tubes having bores of non-circular lateral section, and not for those having circular lateral section. The tube bore mandrel was thus free to locate itself in conformity with t I tering hole indented a short distance within the forwardend of the solid blank, in the case of the usual tube piercinglmill; and, when this indented hole was traversed by the mandrel, was thereafter controlled only by the irregularly opened core fissure ahead of same within theblank.

While, in the case of the usual tube reeling mill, the usual tube rolling mill, and the usual tube drawing bench, the tube bore mandrel .was free to locateitself in conformitywith the previously formed bore in the tubularblanki, This haphazardmethod, of operation of the tube bore mandrels has been the cause, not only of inaccuracy in the location of the bores relative to the outside surfaces of the tubes thus produced, but also of the excessive costs of production, due to site thinner sideof the wall of as well as loweringthe roduction by these mathe previously formed cen- (CI. 8018) s v the. excessive number of" operations required to securethe slight degree of accuracy obtainable, and theincidental spoilage of material accom Denying the method. In the employment of the floating type tube bore mandrels, the assumption was made that, iorequally distributedbalancing forces laterally about the pass, for "both the roll ers and the die, a familiar law of materials, whereby the rollers orthe die ,thicker side more than the diametrically oppothe blank, would be applicable if the number of operations were sufficiently large. However, this law of materials is perfectly eflective only for homogeneous materials, of thin rather. than thick wall section, and of uniform density and hardness; all of which are contrary to the usual qualities of the would reduce the more accurate clue to the larger number of :operations thereon, as well as greater effectiveness of the law of materials mentioned with respect thereto. These statements are borne out by published data on tubes made-on a commercial basis,

the variations in wall wall tubes, under tenper cent plus and minus fromthe nominal wall thickness; -for thick wall tubes, from ten to twenty-five per cent plus and minus from the metrically opposite the plus side, or thick side, of the tube considered. Where there was a fair degree of accuracy, the tubes was exceedingly thin,-;and the numberof operations enormous, with selectedv expensive material, and all conditions not to be duplicated on a commercial basis.

With the controlled type tube bore mandrels of my invention applied to all these machines, each operation results in a perfectly accurate blank or tube, as the case may be, from the initial tube piercingand reeling operations, through thetube rolling operations to the final tube drawing operations, regardless of whether the wall thickness of the blank or tube is thick or thin, or whether the material is homogeneous or not. No reliance is placed upon the law of materials mentioned above, contrary to what was seen true with the floating type tube bore mandrel; though the law will obviously still be effective and helpful as hitherto. 'Also, in the case of tubes having nonthickness being: for thin nominal wall thickness; the minus side, or thin, side, in each case being diawall thickness of the circular section bores, there are means provided which maintain the bore of the tube, as it leaves the pass in each case, in alignment with the forming surfaces of the tube bore mandrel within the pass; thus, there can be no relative rotation between the forming surfaces of the tube bore mandrel and the bore of the tube, as prevailed hitherto in the case of the floating type tube bore mandrel, and which rendered accuracy in the relation between the bore and the outside surface of such tubes unattainable with the latter type mandrel. It is therefore clear that the number of operations, with the controlled type tube bore mandrels, will be very much less than formerly with the floating type tube bore mandrels, since the cause for the formerly prevailing excessive number of operations is avoided by the employment of the means of my invention. Likewise, by presenting an accurate blank for'each operation, particularly for the drawing operations, spoilage of material will be eliminated, since tearing of the blank walls wasformerly due to unequal wall thickness thereof. Production of seamless tubes, by the employment of controlled type tube bore mandrels in all these machines, should therefore be accompanied by lower costs as well as superior accuracy as compared with former costs and accuracy.

While my invention relates to all tube forming machines of the described class, and as such is fully covered by the appended claims, the existing types of tube rolling machines are not considered by me as well adapted to the effective application of my invention thereto as the disk roller machine for helicallyrolling seamless tubes herein shown and described in detail as the preferred embodiment of same. Several of the new characteristicsof seamless tubes, now given as follows, will be seen to be due to the peculiar qualifications of the disk roller machine alone,

and not found in the case of applications of my ,7

invention to the other machines:

(1) The outside surfaces and bores of all tubes are coaxial, whereby tubes having circular cylindrical outside surfaces and bores have walls of uniform thickness. bores of all tubes are perfectly straight longitudinally. circular cylindrical for all tubes, and the bores are uniformly of the form required. (4) The outside surface diameter dimensions are uniform for an indefinite number of tubes, since there is not any appreciable wear of the faces of the disk rollers; and the same is true of the bore dimensions, regardless of whether the bores are cylindrical or non-cylindrical, or are of circular or non-circular lateral sectional form. (5) The material of the walls of all tubes is uniform in density and hardness and in strength, due to the superior rolling action of the disk rollers. (6) The surface finish on all tubes is uniformly smooth, due also to the superior rolling action of the disk rollers.

The characteristics (1) and (2), given above, apply also to tubes made by all other tube forming machines of the described class. In addition, particularly in the case of tubes having the outside surfaces and bores thereof of non-circular lateral section, as, for example, of hexagon lateral section, the apexes of the hexagon section of the outside surface and of the bore will be in radial alignment as required; and for other sections as well, the relation between the sections will be as required, due to the means provided for guiding the bore of the tube in alignment (2) The outside surfaces and (3) The outside surfaces are uniformly with the forming surfaces of the tube bore mandrel within the pass, as mentioned before. Since the outside surfaces of tubes helically rolled by the disk roller machine are circular cylindrical in all instances, the additional characteristic of tubes mentioned above applies to tubes made by the other tube rolling machines and the tube drawing bench.

The chief objects of my invention are, to provide in a tube forming machine of the described class:

First, means coaxially adjacent to the pass for positively guiding the outside surface of the tube coaxially with the said pass.

Second, means adjacent to the said pass coaxially connected to the mandrel means for positively guiding the bore of the tube coaxially with the said mandrel means within said pass.

Third, means coaxially connected to said mandrel means and said bore guiding means and tightly coaxial contacting with the said outside surface guiding means adjacent to said pass for positively'locating and holding the said mandrel means and said bore guiding means coaxial to each other and respectively coaxial within said pass and to said outside surface guiding means at the start of the tube forming operation, whereby the said outside surface and said bore of said tube are formed coaxial to each other.

Further objects are:

First, to provide the means substantially as herein described, as best adapted for the achievement of the above objects, particularly when applied to narrow-pass machines such as the disk roller machines and the tube drawing bench, and thereby to secure the six improved characteristics in tubes before mentioned.

Second, to permt production of seamless tubes at reduced cost, through reduction in the number of operations, and elimination of spoilage of material, heretofore due to use of the floating type tube bore mandrels.

Third, to permit more economy in the purchase and use of tube material, by permitting the purchase of tubes exactly suitable for given installations by merely specifying the nominal wall thickness required, with full assurance that no failure of tube material in service is possible, as contrasted with the former necessity of purchasing tubes having wall thicknesses of from ten to twenty-five per cent heavier and costlier, due to the former non-uniform wall thickness, in order that the expected thinnest wall sections have sufficient strength, and without any assurance that failure of the tubes in service would not follow, due to the unpredictable conditions of tube producton with the floating type tube bore mandrels.

Fourth, to permit extension in the uses of seamless tubes, permitted by reduction in cost and through greater accuracy brought about by my invention, not only for old but also for new applications thereof, such as: tubular shafting, for all power transmission purposes, which require uniform wall thickness for dynamic balance;

structural purposes, as frames for airplanes, bicycles, and furniture; machine parts. such as sleeves, bearing bushings, etc.; piping purposes, such as steam piping, compressed air or ammonia piping, oil refinery and other processes in which high pressure piping is used; and also for boiler and condenser tubes.

The tubular blanks, from which the seamless tubes are helically rolled, are prepared in the same manner as in the past.

the positively controlled tube bore ,mandrel,

The materials for the seamless tubes may be the same as hitherto employed, viz, steel,

wrought iron;copper, brass, bronze, aluminum, nickel, and various other metals and alloys,t be rolled while at the usual rolling heat, or while cold (ordinary temperature), in accordance with theusual practice with thesemetals. Many nonmetallic materials such as vulcanized fibre of various kinds, vulcanized rubber, Bakelite, and

other compositions besides these, may be helically rolled afterfbeing made suitably ductile for the purpose. Seamless tubes may be produced. directly from the prepared tubular blanks by the machine of my invention, or may be produced with the in termediate operations, or the final operations, 6 theblanks performed by the existing tube forming machines, depending'upon the kind of tubes '1 beingmade and their dimensions, as follows:

(1) All tubes having circular cylindrical outside surfaces with the bores ofythe form described of largeenough diameter to permit forming same over amandrei, as inthepast, may be produced directlyby the machine of my invention from the prepared tubular blanks tl'ienumber ofpasses depending upon the reduction in wall thickness, thereduction of the outside surface diameter, the reduction of the bore diameter, or boththereduction of the outside surface and the bore diameters. 1

(2) Tubes havingnon-circular cylindrical out side surfacesgor tubeshavingcircular cylindrical outside surfaces but of such small diameters as to forbid being formed over a mandrel, are produced by helically rolling the tubular blanks in my machine preliminary to rolling or drawing in finished tubes." U 1 l (3) Tubesof circularcylindrical formon both the outside surface and the bore, whichrequire greater speed of handlingthan is possible by the machine of my invention, such as hot rolled boiler tubes, are produced most efficiently by performing the preliminary'and the final passes in my machine and theintermediate passes in the existing types'of tube rollingmachines.

Besides the diskroller machine for helically rolling seamless tubes, constituting. the preferred modification of my invention, the positively controlled tube bore mandrels ofmy invention may be applied to six other types .oftube forming machines later fully described herein. V Inlthe accompanying drawingsz i Fig. 1 is a plan view, of the disk roller machine for helically rollingseamless tubes, provided with comprising the. preferred modification of my invention'. T Fig. 2 is an enlarged fragmentary sectional side view, taken along uneven line .2--2-2 in Fig. 1. i

Fig. 31s a sectionalend view, taken along line 3 -3 in Fig. 2.

Fig. 4- is a fragmentary sectionalend view,

taken along line 4-4 'in Fig. 2.

i Fig. 5 is an enlarged endview, taken along line 5-5 in Fig. 1, showing the forward end of the Fig. 6 is an enlarged end view, taken along line 6-6 in Fig. spindle housing. 1 l a a Fig. 7 is an enlarged fragmentary sectional side view, taken along line 1-1 in Fig. 1,?showing in diagrammaticform the essential parts of 1, showing therear end of the i3 themachine involved in helically rolling seamless tubes. e Q Fig.- 8 is a fragmentary sectional end view, taken along line 8-8 in Fig. 7,'of the mandrel rod, support bracket, yoke, and collars. Fig, 9 is -anf,enlarged fragmentary sectional side view, taken alongline 9-8in' Fig. 1, showing. the start of the tube rolling operation on the tubular blank.

Fig- 10 is a side .view of the mandrel locating and holding sleeve, seen in sectional side view in Fig. 9, within the bore of the tube guide bushing and over the forward endaextension of the longitudinallystationarily held tube bore mandrel. r

Fig. 11 is a jfragmentary 'sectio 1 end view, taken alongline l| ll in Fig. 10, Mel locating and holding sleeve.

Fig. 12 isa fragmentary sectional end view. taken along line |2-l2 means for locking the mandrel locating and holding sleeve v'thin the bore of the tube guide bushing, as well as the unlockedposition thereof during the tube rolling operation.

Fig. 13 is the same as Fig. 9 otherwise, but shows the mandrel locating and holding sleeve being progressively displaced fro 'ngwithin the bore of the tube guide bushing and from over the.

forward end extension of the longitudinally stationarily held tube bore mandrel by the forward end portion of the helically rolled tube during the tube rolling operation on the tubular blank.

Fig. 14 is a sectional end view,,taken along line "-44 in Fig. 13, showing parts related to the tubular blank.

Fig. 15 is a sectional end view, taken along line I5-l5 in Fig. 13. showing parts related to the tube.

Fig. 16 is an enlarged side view of a portion of the tubular blank partially helically rolled to form the tube, showing on the outside surface of the tube in diagrammatic form the relation between the helical pathsof the tube rolling faces on the disk rollers, the narrow pass being indicated by two lateral lines at the juncture of the tube with the tubular blank from which it is formed, also disk rollers is shown dotted to illustrate'the angular relation between same and pass and tube and to show the small contact area for eachof the tube rolling faces of the disk rollers.

Fig. 17 shows the relation between the disk roller and the grinding wheel during the operation of grinding the concave tube rolling face of the disk roller.

Fig. 18 is a front grinding wheel seen in Fig. 17.

Fig. 19 is an enlarged fragmentary section, taken alongradial line i9- l9 in Fig.18, of the disk roller.

Fig. 20 is an enlargedfragmentary end view, taken along'line 20 20 in Fig. 13, of the tube e bushing in the bore of the split bearing of the tube guide bushing .carriage,showing the provisions for lubrication of the bore of the tube guide bushing, and the clearance notches in the rear end of the tube guide bushing as well as in the split bearing. T

lilig. 21 is a fragmentary sectional siue view, taken along line 2l--2liin Fig. 20, of the tube guide bushing and the split bearing.

Fig. 22 is a fragmentary section, taken, along radial linen-22 in Fig. 20, of the rear end of the tube guide bushingatone of the projections between clearance notches.

of the man in Fig." 9, showing the Fig. 23 is an enlarged side view of the longitudinally stationarily held tube bore mandrel, showing provisions for lubrication of the circular cylindrical outside surface thereof, the dotted fragment of one of the disk rollers showing the longitudinal relation between same and the grooves on the mandrel.

Fig. 24 is an end view of the forward end of the mandrel seen in Fig. 23.

Fig. 25 is a side view of the longitudinally movable tube bore mandrel, showing the tubular blank in place thereon preparatory to the tube rolling operation, a fragment of one of the four disk rollers being shown (dotted) to indicate the relation to the replaceable mandrel locating and holding sleeve (in section) on the forward end shank of the mandrel at the start of the rolling operation.

Fig. 26 is an end view at the shank end in Fig. 25.

Fig. 27 is an end view at the mandrel end in Fig. 25.

Fig. 28 is a fragmentary sectional plan view of the disk roller machine for planetarily cross rolling seamless tubes, provided with the positively controlled tube bore mandrel, in which the spindle housing with disk rollers is rotated at a fixed location, and the tubular blank is fed longitudinally forward through the pass of the disk rollers by auxiliary feeding means, comprising a second modification of my invention.

Fig. 29 is a fragmentary sectional plan view of another disk roller machine for planetarily cross rolling seamless tubes, provided with the positively controlled tube bore mandrel, in which the spindle housing with disk rollers is rotatably mounted on a slidably mounted carriage adapted to be longitudinally moved over machine ways, and the tubular blank is held in fixed position while the pass of the disk rollers is caused to be moved longitudinally thereover as the carriage is longitudinally moved over the machine ways by the actuating means therefor, comprising a third modification of my invention.

Fig. 30 is a fragmentary sectional side view, taken along the axis 2i0-2l0 in Figs. 28-29, showing the modification of the positively controlled tube bore mandrel required for rolling cupped-end tubular blanks in the disk roller' machines seen in Figs. 28-29, as applied particularly to a stationary type mandrel. A universal joint connection between the mandrel and mandrel rod is shown.

Fig. 31 is a fragmentary sectional side view of the positively controlled tube bore mandrel as applied to the otherwise usual tube drawing bench, showing the modified die head having the drawing die and tube guide bushing assembled therein, and the stationary type mandrel for drawing cupped-end tubular blanks, the latter being in all respects identical with the mandrel seen in Fig. 30, comprising a fourth modification of my invention.

Fig. 32 is a fragmentary sectional side view of the positively controlled tube bore mandrel as applied to the otherwise usual grooved roll tube rolling machine, showing also a sectional end view of two of the grooved rolls, and the stationary type mandrel and other details similar to those shown in Figs 1-13, comprising a fifth modification of my invention.

Fig. 33 is a fragmentary sectional plan view of the positively controlled tube bore mandrel for tube piercing as applied to the otherwise usual so-called Stiefel tube piercing and reeling mill,

showing also a plan view of the two rolls of the mill, comprising a sixth modification of my invention.

Fig. 34 is a sectional view taken along line 34-34 in Fig. 33, showing the roll-clearance notches and the projections between the rolls of the rear end of the tube guide bushing in Fig. 33 similar to those seen in Figs. 20-21.

Fig. 35 is a fragmentary sectional plan view of the positively controlled tube bore mandrel for tube piercing as applied to the otherwise usual so-called Mannesmann tube piercing and reeling mill, showing also a plan view of the two rolls of the mill, comprising a seventh modification of my invention.

Fig. 36 is a sectional view taken along line 33-30 in Fig. 35, showing the roll-clearance notches and the projections between the rolls of the rear end of the tube guide bushing in Fig. 35 similar to those seen in Figs. 20-21.

Referring now to the drawings:

In Fig 1 is seen the tubular blank i, having outside surface 2 and bore 2, to the left or rear end of the machine with respect to the disk rollers 3, and the helically rolled portion of the blank I forming the tube 4, having outside .surface and bore 6, to the right or forward end of the machine with respect to the disk rollers 3. The portion of the blank I has been helically rolled to form the tube 4 after passing between the conical faces I and through the pass 24 of the tube rolling faces 8 of the four disk rollers 9 and over the circular cylindrical outside surface it of the longitudinally stationarily held tube bore mandrel H longitudinally within the pass 24, from left to right as indicated by the horizontal arrows. After passing the four disk rollers 9, the outside surface 5 and the bore 6 of the tube 4, respectively, passes through the bore 12 of the tube guide bushing 12, and over the forward end extension of the outside surface ill of mandrel ii within the bore i2 of bushing ii. The four disk rollers 9 are individually removably rigidly mounted upon and rotatably driven by the four spindles 14, as best seen in Figs. 2-7, and the latter are individually rotatably mounted in the forward bearing bushings l5 and the rear bearing bushings ii in eccentrically located bores I! in the four eccentric sleeves is, only one eccentric sleeve I8 being seen here. Each sleeve I3 has a worm gear 19 integral therewith at the rear end thereof coaxial with the circular cylindrical outside surface 20 thereof, as seen in Fig. 2, and each worm gear I! meshes with a worm 2| The four worms 2i have each an integral square (not shown), axially projecting from one end and.

a plain shaft 22 projecting from the opposite end, to permit individually manually rotating same and thereby the worm gears i3 and the sleeves II when making radial adjustments individually of the tube rolling faces I of the disk rollers 9 relative to the longitudinal axis 23-22 of the pass 24 of the faces I. The four eccentric sleeves 18 are rotatably mounted in four bores 25 in the spindle housing 28, the bores 25 being laterally equally spaced about the longitudinal axis 23-23 of the pass 24 (see Fig. 5) coinciding with the longitudinal axis of the bore I2 of the tube guide bushing i3 and of the tube bore mandrel Ii. The longitudinal axis 21-21 of each of the four bores 25, coinciding in each instance with the axis 28-23 of the outside surface 2l| of each eccentric sleeve l8 rotatably mounted therein, is at the same angle 29 with the longiit tudlnal axis tudinal axis 23-23 oi'wthe I8, the longitudinal axis 39-30 of the eccentrically located here I! is parallel to the longitudinal axis 28-28 of the i 8 of the disk rollers 9 are outside; surface thereof, being separated by a distance equal to the eccentricity 3|. Thus, when radial adjustments of the tube rollingfaces being made relative to the longitudinal axis 23-23 of the pass 24, each of the four eccentric sleeves I8 is individually rotated (by means of worm gear I!) and worm 2| and square end shaft-22and crank handle) about its longitudinal axis 28-28 of the outside surface 20 thereof to secure a radial adjustment of each individual tube rolling face 8 equal in amount within the limits of two times the eccentricity 3|, as best seen in Figs. 2-4, and collectively forall the tube rolling faces 8 within the limits of four timesthe eccentricity 3|. The tube rolling diameter capacity range of theset of fourdisk rollers 9, each having the same diameter dimension ofthe tube rolling face 8, extends from the minimum diameter of the outside surface 5 ofthe tube 4 to the maximum diameter of the outside surface 5 of the tube 4, the latter maximum diameterbeing equal to the minimum diameter plus four times the eccentricity 3|. By employing anumber of different sets of the four disk rollers 9, each individual set having its individual diameterdimensionof the tube rolling faces 8 different from those of the remaining sets and "varying successively in an ascending order by four times the eccentricity 3|, the set with the smallest diameter dimension of the tube rolling faces 8 is adaptedto roll the largest diameter of theoutside surface 5 of the tube 4 within the diametercapacity range of the machine, and the set with the largest diameter dimension of thetube rolling faces 8 is adapted to roll the smallest diameter of the outside surface 5 of the tube 4 within the diameter capacity range of the machine, with intermediate sets with theintermediate diameter dimensions of the tube rolling faces 8 adapted to roll the intermediate diameters of theoutside surface 5 of the tube ,4 within the diameter capacity range of the machine. The tube rolling faces 8 of the disk rollers 8 thereof without necessitating renewal of the sets for an appreciable time, andwhile maintaining the full diameter capacity range of the machine with these sets, as with no overlapping of the ranges any grinding would change the capacity range of the set ground and thus would require renewal thereof -to range of the machine. Overlapping is accomplished by adding a smal amountto the diameter of the t'uberolling faces 8 of each set beyond that actually required in computing these dimensions of. the .tubelrollingfaces 8 successively in ascending order as described. The forward tubular blank guide bushing 32, having outside surface 33 with shoulder joining to a larger diameter rear end outside surface 35 to "fitremovably rigidly within the central bore 36 and against shoulder; 31 spindle housing .26 respectively, is keyed in place bymeans of K y 39.,to,prevent rotation thereof and the bore thereof is coaxial-withthe longicounterbore 63 maintain the full pass 24, as seen in ,and counterbore, 38 in the.

by the "pinion 14 23-23 of the pass 24 and has a surface 2 of the blank |'to serve as a guide to the blank I during the tube rolling operation to prevent whipping of the blank I which would otherwise occur. Thebushing 32 mustbe replaced by another for .each size, of the diameter of the outside surface 2 of the blank I. 'I'he four spindles |4 have each ah integral universal joint yoke 4| at the rear end thereof connectedby means of the usual universal joint cross 42 to a double universal joint yoke 43, the latter being connected to a second universal joint cross 42 connected with the universal joint yoke 44 integral with the spindle drive shaft 45. The four spindle drive shafts 45 have each a spindle drive gear 46 mounted midwaythereon and keyed in place by means of key 41. The four spindle drive gears 46 are laterally equally spaced peripherally ing housing 53, andat the rear end thereof in bearing bushing 54 in the bearing 55 of the rear bearing pedestal 56, to rotate coaxially about the longitudinal axis 23-23 of the pass 24. The rear tubular blank guide bushing 51, having outside surface 58 with shoulder 59 joining toa larger diameter adapted to fit removably rigidly within the coaxial bore 6| and against shoulder 62 and in in the tubular extension hub 49 respectively, being keyed in place by means of key 64 to prevent rotation thereof relative to the hub 49, and held in place by retainer ring 65 attached to the rear end of the hub 49 by cap screws (not shown) to prevent endwise movement thereof, the bore 66 thereof beingcoaxial with the longitudinal axis 23-23 of the pass 24 and slightly larger in diameter than the'outside surface 2 of the blank I, to serve as aguide for the blank I and prevent "whipping of the latter which would otherwise occur during the tube rolling operation. One such bushing 51 must be provided for each diameter size of the outside surface 2 of the blank I. The four spindle drive shafts 45 are each individually rotatably mounted in bearing bushings'fil in laterally equally spaced bearings 68 of the forward bearing housing 53 at the forward ends thereof, and in bearing bushings'GS in laterally equally spaced bearings 10 of .the rear circular bearing ring ll (located between the forward bearing housing 53 and the rear bearing pedestal 56) at the rear ends thereof. The rear circular bearing ring II has three forwardly projecting pads 12 which abut upon and are attached to three correspondwith forward bearing housing 53 by means of screws (not shown), so that the four spindle drive shafts 45 with the four spindle drive gears 46 mounted thereon rotate about individual axes parallel to the longitudinal axis 23-23 of the Fig. 2. The first intermediate drive gear 59 meshes with and is rotatably driven integral with and rotatably driven by shaft 15 hearing bushings (not shown) in the bearing 16 rear end outside surface 50, is

rotatably mounted in suitable integral with rear circular bearing ring II and in the bearing 11 integral with the gear train double bearing pedestal I8. The shaft 15 is rotatably driven by the second intermediate drive gear I9 mounted thereon and keyed in place by means of a gib key (not shown). The second intermediate drive gear -19 meshes with and is rotatably driven by the pinion integral with and rotatably driven by the shaft 8| rotatably mounted in suitable bearing bushings (not shown) in bearing 82 integral with the gear train double bearing pedestal I8 and in the bearing 83 integral with the gear train single bearing pedestal 84. The shaft 8| is rotatably driven by the flexible shaft coupling 85 keyed-thereon by a gib key (not shown) to connect same to the motor shaft 86, to which the coupling 85 is also keyed by a gib key (not shown), of the electric motor 81. The electric motor 81 is controlled by the machine operator by means of the usual electric motor control switch (not shown) located at a convenient point nearthe machine. As best seen in Fig. '7, the longitudinally stationarily held tube bore mandrel II is integral with mandrel rod 88, and is held against endwise movement by the two retaining collars 09 integral with mandrel rod 88 and abutting against the forward end and rear end of the mandrel rod support bracket yoke formed to receive the hexagon shank 9I between the two retaining collars 89 to hold the mandrel rod 88 and thereby the mandrel itself against rotation. The mandrel rod support bracket yoke 90 is integral with the mandrel rod support bracket 92, the latter being adapted to be moved longitudinally along a special base therefor (not shown) at the rear of themachine and to be reciprocably moved in the vertical direction by suitable power operated means (not shown) controlled by the operator to respectively suit the longitudinal position of the hexagon shank 9I on various lengths of mandrel rod 88 and to permit engagement and disengagement of the yoke 90 with the hexagon shank 9| as required, the operations being later described under the setting-up operation and operation of the machine descriptions. On the same special base for the mandrel rod support bracket 92 are mounted a series of bearing pedestals supporting a like number of semi-circular grooved rollers (not shown), the pedestals being longitudinally adjustable along the base, and the rollers vertically adjustable to suit the size of the blank I beingrolled, to support the rear overhanging portion of the blank I and to facilitate entering the blank I into the machine, the pedestals of course being spaced to avoid interference with the bracket 92. The length of the mandrel rod 88 is such that the tubular blank I will clear the two retaining collars 89 and the yoke 90. The tube bore mandrel II is provided with a forward conical end 93 to facilitate ready entrance thereof into the bore 94 of the mandrel locating and holding sleeve 95 (seen in Fig, 10), and a rear conical end 96 to facilitate entrance thereover of the bore 3 of the tubular blank I, as best seen in Figs. 7-9-13. The tube guide bushing I3, having bore I2 adapted to have the outside surface 5 of the helically rolled tube 4 fit tightly slidably rotatably therein and the outside surface 91 of the mandrel locating and holding sleeve 95 fit tightly slidably therein, has a circular cylindrical outside surface 98 fitting tightly within the bore 99 of the split bearing I00 provided with bearing cap I0 I, and is provided with a projecting annular shoulder I02 fitting within a corre p nding groove I03 in the bore 99 to prevent endwise movement thereof relative to bore 99, and with a longitudinal key I04 sunk in the outside surface 98 thereof fitting a corresponding keyway I05 in the bore 99 to prevent rotation thereof in the bore 99. The bearing cap ml is held in place by means of four studs I06 with hexagon nuts I06, the studs I09 fitting within the corresponding holes in the four lugs I01 thereof and screwing into corresponding tapped holes in' the lower part of the bearing I00, thus by merely unscrewing the nuts I06 from studs I06 the tube guide bushing I3 may be removed when necessary to replace same with another one having a diflerent bore I2 to suit a different outside surface 5 of the tube 4, and the new tube guide bushing l3 may then be as readily clamped in place in bore 99 of the split bearing I00 with bearing cap IOI. The lower part of split bearing I00 is integral with the tube guide bushing carriage I08 slidably mounted on two ways I09 longitudinally parallel to the longitudinal axis 2323 of the pass 24. The carriage I08 is provided with two longitudinal gibs IIO bolted thereto to engage the underside of the projections III of the two ways I09 integral with the carriage base II2, for holding same in place on the ways I09, as best seen in Fig. 12. A laterally adjustable gib H3 is provided to take up wear on the vertical edges of the ways I09, while leaf shims under the gibs IIO are provided (not shown) to take-up wear on the horizontal surfaces of the ways I09. In the setting up of the machine, as later described, in which the position of the pass 24 is actually made to conform to the location of the bore I2 of the tube guide bushing I3, and not vice versa, it will be readily understood that wear of the ways I09. or of the corresponding contacting surfaces of the carriage I08, will in no manner affect the accuracy of the location of the bore I2 of the tube guide bushing I3 with respect to the pass 24, but is conditional that the carriage I08 must be held against all movement during the tube rolling operation and must maintain the settingup position once the latter has been made. The tube guide bushing carriage I09 is adapted to be locked in place against any movement on the ways I09, while at the rearward position thereof and with the tube guide bushing I3 in the operative position relative to the pass 24, by means of lock pin II4 passing through the corresponding hole II5 through the same and the lug I I6 alongside the inner edge of the way I09 and integral with the latter. The tube guide bushing carriage I08 is adapted to be actuated reciprocably longitudinally over the ways I09 by means of pressure fluid actuated piston II! in cylinder II8, the piston III having connected therewith the piston rod II9 having eye-end I20 connected to yoke lug I2I integral with the under side of the carriage I08 by ineans of pin I22, as best seen in Fig. 7. The reciprocation of the carriage I08 is controlled by the operator by means of a valve (not shown, two-way for air, and four-way for oil or water, pressure fluid) in the pipe line from a source of pressure fluid (air, oil, or water) to the pipes I23 and I24 connected to the opposite ends of the cylinder II8 mounted in the carriage base I I2, the pressure fluid flow through pipe I23 causing the carriage I08 to be actuated in the forward direction over ways I09 with the spent fluid leaving the cylinder IIB through pipe I24, while rearward motion of the carriage I09 over the ways I09 is caused by the flow of the pressure fluid through the pipe I 24 into the cylinder i forcing the settingmn mandrel later fully. described) into the m with the spent nuid eavmr the'cylinder through pipe I 23, due to correspondi lations of the valve by the operator.

I I8 ng maniputube guide bushing I3, in order to permit readily (not shown, but bore I2 and in plained, and in forcing the mandrel locating and holding sleeve 95 (seen. in Fig.

I2 of the tube guide bushing I3 and over the out.

side surface III of the tube bore mandrel II.

I as described before. The rearend of the head I3I is separated from the forward end of the split bearing I00 and bearing cap IIII by. a distance greater than the over-all'length of 1 the sleeve 95 and slightly ing 53, therear bearing pedestal 56, the gear train i double bearingpedestal 78, the gear train single bearing pedestal 84, are all rigidly bolted bolts (not shown). ed on a suitable which it is bolted in the usual manner.

and the electric motor 81,

to themainbase I34 The main base I 34 is mount- In Fig. 2 is shown one of the four disk rollers 9 having conical face I and tube rolling face 8 as described, and bore I35 fitting tightlyremovably The rearfoundation (not shown), to

on the forward threaded shank I of one of the roller 9, to prevent rotation of the disk roller 3 relative to shank I36. Collar nut I39, screwed '5 I36, and holds thedisk wise movement relative to shank I36. The direcpressed material overlying and only partially rolled into the surface 5 of the tube 4 produced by the disk roller-9 in question, and this iln in most cases would flake out or leave a helical mark on the surface 5 of the tube 4. Both the forward and the rear edges of the tube rolling face 8 in each instance are slightly rounded to prevent any scoring of the outside surface 5 of the tube 4 thereby. The four disk rollers 9 are each pro- 'vided with a heavy boss I43 at the forward side thereof in order to increase the length of the bore I35 and the keyway I38 and consequently increase the area in contact with the shank I36 and the key I31 to prevent upsetting of the metal of the contacting surfaces under the heavy loads to which they are subjected, as well as to increase the strength of the disk roller 9 itself in resisting the very heavy combined radial thrust and rearward longitudinal thrust thereon during the tube rolling operation. Each of the four eccentric sleeves I8 is securely clamped -in place, after the individual manual adjustments of the tube rolling faces 8 of the disk rollers 9 have been made as described, individually in the four bores 25 in the spindle housing 26 by means of two set screws I44 in each case screwed through the walls of the bores 25 (the screws I44 shown dotted, the wall of bore 25 being cut away in this view) and abutting against the outside surface 20 of the sleeve I8. The four eccentric sleeves I6 are each held against endwise movement in their individual bores 25 in the spindle housing 26 in each instance by means of the forward and rear sides of the worm gears I9 integral therewith and contained in the counterbore recess I45 in the split combined,worm and worm gear housing I46 attached in each case by means of screws I41 to the four rear bosses I48 at the rear ends of the bores 25. The worm 2| is seen in mesh with the worm gear I9, the plain worm shaft 22 being dotted, while the square end worm shaft 22 being in the right half of the housing I46 does not appear in this view, as only the left half of housing I46 is shown. To facilitate illustration the parts in this view are shown coaxial, though the true relation therebetween is non-coaxial as seen in Fig. l. The longitudinal axis 28-28 of the outside surface 20 of the eccentric sleeve I8 (coinciding with the axis 21-21 of the bore 25 in spindle housing 26 in each instance) is seen to be parallel to the longitudinal axis 30-30 of the spindle I4 and disk roller 9 (coinciding with the axis of the eccentrically located bore I! in sleeve I8) separated by the distance equal to the eccentricity 3|.

In Fig. 3 is shown the split combined worm and worm gear housing I46 having the counterbore recess I45 containing the worm gear I9 meshing with the worm 2I, with the square end worm shaft 22 and plain worm shaft 22 coaxially projecting from each end of worm 2I rotatably mounted in bearings I and I49 respectively in the right and left halves of housing I46, attached by screws I41 to the boss I48 (seen in Fig. 2). Two collars I5I are screwed onto shafts 22 and 22' to prevent endwise movement of the latter in bearings I50 and I49. The set screws I52 are employed to prevent inadvertent turning of shafts 22 and 22', after adjustments of the tube rolling faces 8 of the disk rollers 9 have been made as described.

In Fig. 4 is shown one of the four eccentric sleeves I8 rotatably mounted in one of the four bores 25 in the spindle housing 26 to rotate about the longitudinal axis 28-28, and one of the four spindles I4 rotatably mounted in the forward bearing bushing I5 (the rear bearing bushing I6 being in the part cut away in this view), pressed in place in the eccentrically located bore I1 of the eccentric sleeve I8, to rotate about longitudinal axis 30-30. The longitudinal axes 28-26 and 30-30 are parallel to each other and separated by the distance equal to eccentricity 3|, so that the rotation of the sleeve I8 about axis 28-28 causes the axis 30-30 to describe a circular cylindrical surface having a radius equal to eccentricity 3| when the full adjustment of the tube rolling faces 8 of the disk rollers 9 is made with relation to the longitudinal axis 23-23 of the pass 24, the full radial adjustment of the latter then being twice the eccentricity 3I or the diameter of the small circle of radius 3I seen here. A fragment of the forward tubular blank guide bushing 32 (seen slightly in perspective here) is shown within the bore 36 in the spindle housing 26, the bore 40 being coaxial with the longitudinal axis 23-23 of the pass 24.

In Fig. 5 is shown the forward end'of the spindle housing 26, and the four disk rollers 9; the four spindles I4 are dotted in to show their longitudinal axes 30-30 parallel in each instance to the longitudinal axes 28-28 of the four eccentric sleeves I8 (the latter not being shown), and the two axes 30-30 and 28-28 in each instanceare angular to the longitudinal axis 23-23 of the pass 24. The pass 24 in this view coincides with the outside surface 5 of the tube 4 within the bore I2 of the tube guide bushing I3. The outside surface 98 of the tube guide bushing I3 is within the bore 99 of the split bearing I00 and bearing cap IOI as seen, only the projections I53 between the four disk rollers 9 of the bearing I00 and cap IOI being seen here in full line, while the projections I54 of the tube guide bushinglii are shown dotted between the four disk rollers 9. The projections I53 and I54 are seen also in Figs. 20-21, The direction of rotation of the disk rollers 9 and spindles I4 is indicated by the curved arrows and is seen to be clockwise (right hand), while that of the tube 4 also indicated by a curved arrow is seen to be counter-clockwise (left hand) The bottom surface I55 of the spindle housing 26 is machined to adapt same to fit corresponding finish pads on the top surface of the main base I34. The bolt holes I56 (dotted) are provided to receive bolts (not shown) for attaching the spindle housing 26 to the main base I34 on the finish pads mentioned. The mandrel rod 88 is shown dotted to the rear of the tube bore mandrel II within the bore 3 of the blank I, and is coaxial with the bore 6 of the tube 4 and to longitudinal axis 23-23 of the pass 24. It will be readily apparent that the mandrel rod 88 may be employed forward of the tube bore mandrel II when desired, instead of to the rear of the latter as here shown, without affecting the operation of the tube bore mandrel II, though causing the mandrel rod 88 to be thrust loaded instead of tension loaded as in the application herein shown, which would not be desirable in the case of long or small diameter mandrel rods 88 due to excessive sagging and buckling of the same under load. The mandrel locating and holding sleeve 205, employed with the movable type tube bore mandrel 202, seen in Figs. 25-26-27 and later described, would have to be employed in place of the sleeve 95 in the event that the mandrel rod 88 is applied forward of the tube bore mandrel II, in order to avoid interference with the bore I30 in the head I3I of the sleeve support bracket I32 by the hub 12! and eye-lever III of the sleeve the bore l2 of the tube guide bushing l3, besides 95 which would occur-otherwise. By mounting servingin the capacity mentioned above, serves gthe sleeve support bracket I 22 on a horizontal I to. guidetheoutside surface I of the tube 4 1011-. jaxispivot, ,topennit swinging same upward out gitudinally coaxially forwardly adjacently in 5 of the way when not muse; thedifllculty, with alignme'ntiwith the, tube rolling faces. of the 5 the sleeve"! as outlined may be. avoided. four disk, rollers a tangent to the pass 24, so that ,InFig. 6 the rearend of thespindlehouslng 26 the outside surface 5 of the tube 4 .is perfectly is shown,the direction, of rotation of the parts jstraight longitudinally for it'sfull length. The beingse'ento be opposite tothat shown in Fig. 5 Qoutside surface III of the forward end extension for obvious reasons, and the location of the square of the, tube bore mandrel H within the bore I2 10 end worm shafts 22 isseen to behest suited to oftheitubeguide bushing i3, besides serving in 7 permit ready'accessfthereto by the operator. 'thefcapacity'mentioned above, serves to guide f In Figs; 7-8 the parts, shown have been fully v the beret of the tube 4 longltudinally coaxially describedin connection; with Figs. 1-2. forwardly adjacentlyjin alignment with the out- In- Figs- 9 10 1l- -12- 13+-l4-15 are shown a the side surface ID of the tube boremandrelll within 15 detail parts associated withthe application of the "thepass24during the'entire course of the tube fniandrelilocating andholding sleeve 95 ,to the rollingoperation on thetubular blank I; (incobore l2ofthetube guide busliing l3 and to the omration'with bore 12 of'the tube guidebushlng outside suriac IIIv of theforward end extension ilandjthe sleeve'llandthe tube 4), so thatthe of the tubeborefmandrel ll,iwhile the forward bore a ofthe tube4is perfectly straight longig0 endportion offlthe tubular blank I isprogressively tudinallydor its fulllength, as seen in Figs. 'helically; rolled within thepass 24 to progressively 7-9,13.3The foregoing functions apply to all form the forward end portion of thetube 4f(equal modifications of the two typesof tube bore maninlength to the length of the bore 1l2of the tube .drels, for all lateral sectional forms of the bore I 25 guide bushing I2) ,,.for the purpose of locating "of the tube 4. Where the bore 6 is of non-circular 25 and holdingthetubeboremandrel ll longitudilateral sectional form, an additional function nally coaxially within the, pass 24 during this arises, and thestationarily heldtubeboreman period. The start of. thetube rolling operation drel It must be modified to suit, as describedin on the tubular blank! is seen in Fig. 9, with the connection with Figs. 16-2344. to comprise a forward end of the tubular blank ljust conrotatablymounted cylindrical sleeve on a sti- 30 tacting with thei'ear end ofthe mandrel locating tipnarlly held sh nk s ta vco c ed to the and holding-sleeve 95. As the tube rolling onma'ndrelrod Ill. The outside cylindrical surface 'eration proceeds, thefmandrel locating and holdoi'jthe. sleeve, having the same lateral sectional ing sleeve 95. is progressively displaced; from form and dimensions as the required bore] of i 5 #withinthebore 12 of thetube guide bushing l3 7 the tube 4, in thecase of the stationarily held and, frorngoverthe outside surface, of the tubebore mandrel Ii, is operable in the same 1 forward end extension of the .tube boremandrel ,n annerjasthe cylindrical or non-cylindrical outll within the bore l2 of the tube guide bushing side, surface 1 202 of the longitudinally movable i3 byftheprogressi vely formed forward end portype tubefbore mandrel 202, described" in contion of thetube .4, as seen inFig. 13,, the tube'4 nection with Figs. 2546-27, in that the forward 0 r thus progressivelywassuining the same function end extension thereof, in both cases within the astheqmandrel locating and holding sleeve 95 bore of the "tube guide bushing 12, serves to in locatingandholding the tube bore mandrel ll hold the" forming surfaces thereof within the A longitudinally coaxlally within the pass 24, and pass :lfasai'n t any rotary movem t r l tiv to i serving. iointlywiththe mandrel locating and theiboreb of'the tube 4Wh11e guiding h'b re 3 5 holding sleeve 9! in this capacity in, cooperation in j'aligmnentwith the forming surfaces thereof, with the bore i2 of the tube guide bushing i2 and throughout the tuberolling operation on blank I. the outsidesurface ii of the forward end ex- Thus, where the bore his hexagonalin lateral tension of. the tube bore mandrel H during this sectional form, for example, each apexo'f the period. aftertheniandrelzlocating and holding hexagon will be longitudinally straight throughs sleeve 95 has'been entirely displaced from within out thelengthof thebore 4. Other characterthe bore i2 of the tube guide bushingl3 and from lstlcs of the tube 4, jamong the six mentioned,v over the outside surface it of the forward end followlargely froin the two outlined above. The extension ofthe tube bore mandrel I l withinthe I concentricity or; the outside surface 5 and bore bore l2 of the tubeguide bushing if, the tube 4 6 of the tube 4, and of the bore I2 of the tube in cooperation with the bore l2;of the tube guide guide bushing l2, and oftheoutside surface I0 bushing 13 and the outside surface 10 of the [of ,the forward end extension of the tube bore forward end extension ofthe tube bore mandrel mandrel ll, about: the longitudinal axis 22-22 H serves to iocateand hold the tube bore manof the pass 24, isseen in Fig. l5,to show the unioodrel i longitudinally coaxially within the pass formwall thickness of the tube 4, as contrasted m f 24 while the remaining-portion, of the tubular with thenon-unlform wall thickness of the blank blank i is progressively helically-rolled within the l and the non-concentric relation of the latter pass 24 to progressively form the remaining porto the bore 40 of the forward tubular blank guide tion of the tube 4. Thus, since the tube bore bushing 32 and the mandrel rod 48, seen inFlg.

o5 mandrel ll has been located and held longi- 14', which also shows the necessary clearance retudinally coaxially within the pass 24 throughout ,quired for the blank I in bore 40. In Figs. 10-11 the tuberolling operation on the-tubular blank I isseen" the mandrel locating and holding sleeve the outside surface'i and the bore 6 of the tube having outside surface 81 and. bore 94 re- 4 are formed perfectly. longitudinallycoaxial to spectively of the same lateral form and dimen- 70 h each other forthefulllength thereof. Thetube sions as outside surface I andbore 6 of tube 4, 7 rolling operation on the tubular blank I, after and provided with an enlarged forward end hub the mandrel locating andholding sleeve 95 has I29 (alreadydescribed) toflt within bore I20 in been entirely displaced by the tube 4 as described, the head HI of sleeve support bracket I22 and is seen inli'ig. 7., During theentirecourse of, the an eye-lever I51 for facilitating handling same tube rollingoperation on the tubular blank I, by means ofa crane chain andhook, the two 7 split bearing I00 and bearing cap IOI' formed between the forward end of the tube guide bushing I3 and the inwardly projecting annular end shoulder I of the bearing I08 and cap IOI seen in Fig. 13, the two lugs I58 being permitted to enter the groove I59 through the, two radial slotted openings I6I and I62 forward of the groove I59 at the forward end of the bearing I00 and cap IOI. A pin I63 serves as a stop for the eye-lever I51 to insure proper register of the two lugs I53 with the slotted openings I6I and I62 when the carriage I08, forces the mandrel locating andholding sleeve 95 into the bore I2 of the tube guide bushing I3 as seen in Figs. 9-12 When the assembly of the mandrel locating and holding sleeve 95 within the bore I2 of the tube guide bushing I3 is forced over the outside surface I0 of the forward extension of the tube bore mandrel I I by means of carriage I03, the eye-lever I51 is turned through 90 degrees as seen in the dotted position in Fig. 12 to lock the lugs I58 within the groove I59 and thus prevent relative movement of the mandrel locating and holding sleeve 95 within the bore I2 of the tube guide bushing I3. After the mandrel locating and holding sleeve 95 has been thus completely assembled within the bore I2 of the tube guide bushing I3 and over the outside surface I0 of the forward extension of the tube bore mandrel II within the bore I2 of the tube guide bushing I3, the eye-lever I51 is again returned to the vertical position as seen in Figs. 9-12 in order to register the two lugs I53 with the slotted openings I6I and I62 and permit the mandrel locating and holdingsleeve 95 to be displaced from within bore I2 and from over the surface I0 asseen in Fig. 13 during the tube rolling operation. While the above description applies to the longitudinally stationarily held type of tube bore mandrel as seen in Figs. 1-5-6-7-9- 12-13-15-23-24, the longitudinally movable type of tube bore mandrel 202 as seen in Figs. 25-26-27 is applied in a very similar manner in connection with the mandrel locating and holding sleeve 205 there shown, as later fully explained.

In Fig. 16 is shown a portion of the tubular blank I and a portion of the helically rolled tube 4 made therefrom, the outside surface 2 and the bore 3 of the blank I being non-coaxial the walls are necessarily non-uniform in thickness, while the outside surface 5 and the bore 6 of the tube 4 are concentric about the longitudinal axis 23-23 of the pass 24 and thus the walls are uniform in thickness. The pass 24 lies between the two lateral lines I64 and I65, the tubular blank I lying to the rear of line I64 and the tube axis 23-23 of the pass 4 lying forward of the line I65. One of the four disk rollers 9'is shown dotted, having its longitudinal axis 30-30 at angle 29 to the longitudinal 24. This view shows the true relation existing between the longitudinal axes 30-30 of all four disk rollers 9 and the longitudinal axis 23-23 of the pass 24 as seen when viewed from each of the four positions I66, I61, I68, I69, indicated by the arrows in Fig. 5, as well as the relation of the tube rolling faces 8 of all four disk rollers 9 to the pass 24. Each of the tube rolling faces 8 of the four disk rollers- 9 contacts with the outside surface 2 of the blank I in a small contact area bounded by two approximately lateral edges I10 and HI produced by the rear edge I10 and forward edge I1I of the tube rolling face 8 and by the two edges I to rotateabout the non-circular cylindrical,

I12 and I13 parallel to the axis "-30 produced by the tube rolling face 8 when entering and when leaving the contact area respectively. The leaving edge I13 will lie directly under the line of the longitudinal axis 30-30 in the figure and between the bounding lateral lines I64 and I65 of the pass 24, and is the momentary limit of the helical path I14 of this particular disk roller 3, the helical paths of the three remaining disk rollers 9 being I15, I16, I11, as seen in the drawings. As seen, the surface of the tube rolling face 8 contacting as it does with a circular cylindrical helical path I14 in the leaving edge I13 lying in path I14, and the leaving edge I13 thus being common to both the tube rollingface 3 and the path I14, the surface of the tube rolling face 8 must be made concave to suit the exact diameter of the path I14. The slight addition to the contact area of the tube rolling face 3 produced by the conical face 1 is located to the rear of the rear edge I10 of the tube rolling face 3, and is therefore to the rear of the pass 24 and the bounding line I64 of the latter, is not shown as it is.not of consequence to the description. From the description of the eccentric sleeves I3, it will be clear that the adjustments made thereby will not alter the angle 29 between the longitudinal axis 30-30 of each of the disk rollers 9 and the longitudinal axis 23-23 of the pass 24, due to the parallelism of the axes of the sleeves I8. The helical path I14 of the tube rolling face 8 of the disk roller 9 shown, is cross hatched to clearly distinguish same from the other three I15, I16, I11, and all four paths are produced simultaneously as the four disk rollers 9 are rotatably driven by the four spindles I4, etc., as described. The angle 29 between the axes of the disk rollers 9 and the pass 24 causes the disk rollers 9 not only to rotatably drive the blank longitudinal axis 23-23 of the pass 24 but to feed the blankl progressively longitudinally forward, so that the material of the walls of the blank is helically rolled between the tube rolling faces 3 of the ,disk rollers 9 and the circular cylindrical outside surface III of the tube bore mandrel II. Where the outside surface I0 of the tube bore mandrel II must be such as hexagonal, etc., the mandrel II must be rotatably mounted on a shank (held against rotation by the mandrel rod 88) or else the longitudinally movable type of tube bore mandrel must be employed which rotates with andmoves longitudinally forward with the blank I and tube 4 as later explained, the mandrel locating and holding slwve having a bore 94 to suit the form of the surface I0 of the tube bore mandrel II in this case as well as with the movable type of mandrel. Collectively, the four helical paths I14, I15, I16, I11, as they are progressively produced by the four tube rolling faces 8 within the pass 24, progressively form the circular cylindrical outside surface 5 of the tube 4. The circular cylindrical bore 6 of the tube 4 is simultaneously progressively formed within the pass 24 by the outside surface I0 of the tube bore mandrel II as the outside surface 5 of the tube 4 is helically rolled, as seen in Fig. 'l. The angle 29 between the longitudinal axes 30-30 of the four disk rollers 9 and the longitudinal axis 23-23 of the pass 24 is likewise equal to the helix angle of each of the four helical paths I14, I15, I16, I11, the latter having each a linear pitch I18 (or lead) in this instance made equal to the diameter of the outside surface 5 of the tube 4. Thus, with the angle 29 constant, the linear pitch I18 fora 4" I v I "3 1 will vary in; direct proportion to the diameter dimension of theoutside surface 5 of the tube 4 being rolled, for all diameters within'the diameter capacity range of the machine. The width I19 of the tuberolling face 8 of the diskrollers 9, based on, the angle 29 and the iinearpitch I18 as given, is equal toone fourth oflthepitch I18, or one-fourth of the diameter of the outside surface 5 of the tube 4, and will also vary in direct proportion to the diameter? dimension of the outside surface 5 of the tube 4 being rolled. Thus, 0. D. tube, the linear pitch I18 will be equal to 4" andthe width I19 will be equalto 1"; while for a2" 0. D. tube, the linear pitch I18 will be equal to 2" and the width I19 will be equal to In any given machine, once the angle 29 has been determined, it cannot, of course,

,be altered in any manner, and therefore the machine must be designed to suit the hardest material which it will be calledfiupon to roll; the harder the material the smaller the width I19 of the tube rolling faces 8 of the disk rollers 9, and, consequently, the smaller the angle 29 and the linear pitch I18 to conform to the width I19.- By employing the width I-19' as herein designated, a slight overlap I80 ofgthe helical paths I14, I15, I16, I11, is proVided thus, the path I 14 overlaps path I15, the path I15 overlaps I path I16, the path I18 overlaps path I11, the path I11 overlaps the path I14, as seen in the drawings. With the data for each set of disk rollers 9 determined inthis manner, the plurality or series of sets of disk rollers 9 to suit the diameter capacity range of the machine is readily computed. While the machine herein described is provided with four diskrollersil, the number of rollers is governed bythesfnallest diameter tube to be rolled and the diameter capacity range of the machine, as is likewise the number of sets of rollers The number of disk rollers 9 emplayed in any size machine should never be less than three, and the larger the number of disk rollers 9 the better.-- This may be seen from the fact that, with the same angle 29, if the number of disk rollers 9 were increased from four to five, the width I19 would be diminished and would be only one-fifth of the linear pitch I18 in place of one-fourth, and would thus serve to "diminish the contact area I1Il'--I1I'I12-I13 of the tube rolling faces 8 bymaking same narrower, thereby decreasing the loading on the disk rollers 9 and the spindles I Iand other connected driving parts.

The increased number of disk rollers'9- also serves to distribute the radial loading on each of the tube rolling faces 8 at smaller angular intervals about the circumference of the-outside surface 2 of the blank I within the pass24, which is very important in reducing the amount of the unbalanced radial loading on the tube rolling faces points oflessradial loading and thereby deflect the tube bore mandrel I I from the desired coaxial relation to ,the pass 24, and cause the tube 4 to be imperfectly rolled if adequate counter means were not provided toprevent such deflection. The

moment arm of the radial loading on each of the tube rolling faces 8 is approximately one-half of the width I19 with respect tothe' rear end of the bore I2 of the tube guide bushing I3, and thus the-decrease in width I19 and the corresponding a 1 1 decrease in theradial loading, with better distri bution at smallangular intervals with greater numbers of disk rollers 9,"is' readily apparent, and

by making the length of the bore I2 of the tube guide bushing I9 very many times greater than the width I19 within practicable limits, the resistance to deflection of the tube [and the tube bore mandrel II within the bore I 20f thetube guide bushing I3 willbe ample to prevent the 1 deflection of the tube 4 and tube boremandrel II within the pass 24. It is for these reasons that I consider-the disk rollers 9 superior to any 7 other form of tube forming means, and the machine herein described the preferred embodiment of my invention. The effect of the long mandrel rod' 88, unsupported between the rear conical end 96 of the tube bore mandrel fII and the yoke 90 of the mandrel rodsupport bracket 92, and, therefore, subject to considerable deflectiondue to its weight, is' to tend to deflect the tube bore mandrel I I from the required coaxial relation to the longitudinal axis 23-23 of the pass 24 during the tube rolling operation. To prevent such action as much as possible, due to the above cause, or due to inadvertent misalignment of the mandrel rod 88 and the tube bore mandrel 'I I, a universal jointsuch as the universal joint 219' seen in Fig. 30, must be connected to the forward end of the mandrel rod 88 and the rear end of the rear conical end 96 of the tube bore mandrel II, one yoke of the universal jointbeing integral with the mandrel rod 88 while the other yoke is integral with the rear conical end 96 of the tube bore mandrel II, a four trunnion cross piece connecting the two yokes in the usual manner. The width I 8I of the conical faces'1 of the four disk rollers 9 will vary in proportion to the width I19 of the tube rolling faces 8, and

must be sufficiently wide to permit the material of the outside'surface 2 of the blank I to contact therewith only within this width and not with the rear edge of the conical face 1. r The angle I82 of the conical faces 1 must conform to the same condition as pertain to the width I8I thereof, and also must serve to prevent the longitudinally forward compression spread of the material of the outside surface 2 of the blank I, as already described. The widths I19 and I8I of the four disk rollers 9 are madesuitable for helically rolling tubes 4 within the diameter capacity range of each set, the widths being the same for each set, but vary between the different sets comprising the series of sets required for the machine. In Figs. 17-18-19, are shown the requirements for grinding the tube rolling faces 8 of' the four disk rollers 9 to the required concavity, as explained in connection with .the description of Fig. 16. The disk roller-9 is to be mounted on a suitable mandrel in a grinding machine, in which the tube rolling face 8 contacts with the faceof the grinding wheel I83 of the same diameter as the outside surface 5 of the tube 4. The

axis I84 of the disk roller 9 being at angle I85 to the longitudinal axis I86 of the grinding wheel I83, respectively corresponding to the longitudinal axis 30-30 or, the four disk rollers 9 at the angle 29 to the longitudinal axis 23-3 of the pass 24 andj the outside surface s of the tube 4 in the tube rolling machine, the required concave surface of the-tube rolling face 8 of the disk roller 9 is accurately ground. The disk roller 9 and the grinding wheel p I83 are independently rotatably driven in the grinding machine to rotate about their respective axes I84 and I86 in thefsame directions of rotation, as seen in Fig. 18. The diameter of the tube rolling faces 9 of the four disk rollers 9 comprising each set must be exactly equal. The conical faces 'I of the four disk rollers 9, are to be ground in'the usual manner in a grinding machine, the angle I92 and the width I9I and the diameter being the same in each set. In Figs. 20 -21-22, is shown the tube guide bushing I9 mounted in the bore 99 of the split bearing I and bearing cap III, as already described, other detail parts being numbered the same. the bore I2 of the tube guidebushing II, two annular'grooves I91 and I99 are cut near each end in the bore I2-and connected by means of helical groove I99 cut therein, small drilled holes I99 at intervals connect the helical groove I99 with an annular recess I9I in the bore 99 of the split bearing I09 and bearing cap III, the drilled and tapped hole I92 being provided in the bearing cap IBI for making connection to suitable flexible piping (not shown) to connect the recess III to other common piping (not shown) connected to a source of lubricant under pressure (not shown). For helically rolling the tubular blank I ina heated state (at the so-called rolling heat), water under pressure must be substituted for oil or other lubricant, in order to prevent distortion of the bore I2 of the tube guide bushing I9 and severe abrasion therein which would otherwise occur, due to the heat in the tube 4 passing therethrough. It is also desirable to direct a stream of oil for cold worked tubes, and water for hot worked tubes, against the outside surface 5 of the tube 4 within the tube rolling space 24, by means of suitably disposed pipes, in order to further secure proper lubrication and cooling. To reduce the friction of the outside surface I of the tube 4 within the bore I2 of the tube guide bushing I9 still furthena rotatably mounted sleeve (not shown), having the same diameter bore as the bore I2, may readily be placed within a suitable counterbore within the bore I2 between the two annular grooves I91 and I99 (the latter grooves being dispensed with in that event) and held against endwise movement by means of a short locking bushing screwed into the counterbore at the forward end up to the point of the groove I99, the bushing also having a bore of the same diameter as the bore I2. Other alternatives to the rotatably mounted sleeve above mentioned consist of: A series of roller bearings, the inner diameter of the bearings being equal to that of the bore I2 to permit the rollers of the roller hearings to contact rotatably with the outside surface 5 of the tube 4; or of a series of roller bearings having inner rings with bores of the same diameter as the bore I2 to permit the bores of the inner rings to contact with the outside surface 5 of the. tube 4 and the rollers themselves rollably contacting with the surface of the counterbore above mentioned; or a series of plain rings having bores of the same diameter as the bore I2 rotatably mounted in the counterbore above mentioned: all these alternative constructions being particularly suitable for cold worked tubes. The conical entrance bore I93 at the rear end of the bore I2 of the tube guide bushing I9 is provided to facilitate the entrance of the forward end of the outside surface 5 of the tube 4 therein, and extends rearward as shown within the projections I54 between the four disk rollers 9 formed by the four clearance notches I94 pro- Yided to clear the forward sides of the four disk rollers 9. The four projections I53 are formed by the four clearance notches I99 provided in the In order to provide for lubrication of rear end of the split hearing I 99 and bearing cap I ll to clear the forward sides of the four collar nuts I99 on shanks I99 of the four spindles I4. The projections I99 and I94 are shaded in Fig. 20 to more clearly show the relation therebetween. The dotted fragment of one of the disk rollers 9 shows the longitudinal relation between the same and the conical entrance bore I99 and the notches I94 and I99 (Fig. 22 clearly shows the entrance bore I93) though not in true radial position with the tube rolling face 9 in longitudinal alignment with the bore I2 of the tube guide bushing I9.

In Figs. 23-24, is shown the tube bore mandrel II provided with mandrel rod 99, and therear conical end 99, and the forward conical end 93, and the circular cylindrical outside surface III, as already described. In order to provide for lubrication of the outside surface III, two annular grooves I99 and I91 are cut in the surface It at each end, corresponding in location to the grooves I91 and I99 out within the bore I2 of the tube guide bushing I9 as seen in Fig. 21, and connected by means of helical groove I99 cut therein, small drilled holes I99 at intervals connect the helical groove I99 with the centrally located longitudinally drilled hole 209 in the body of the tube bore mandrel II, the longitudinal hole 209 being connected to the bore 2M in the mandrel rod 99, the latter in this case being a tube of proper dimensions welded to the rear conical end 99, the bore 29I being provided at the extreme rear end with a tapped hole (not shown) for making connection to suitable flexible piping (not shown) to connect the same to a source of lubricant under pressure (not shown). When the universal joint connection (not shown, describedin connection with the description of Fig. 16) between the rear conical end 99 and the forward end of the mandrel rod 99 is employed, a flexible pipe passing through the trunnion part of the universal Joint must be used to connect the longitudinal hole 299 in the mandrel I I with the bore 2III of the tubular mandrel rod 99, in order to lubricate in the same manner as with the rigid connected tube bore mandrel I I and mandrel rod 99 as above outlined. For helically rolling the tubular blank I while heated (at the so-called rolling heat) water under pressure must be substituted for oil or other lubricant, in order to prevent distortion of the outside surface I9 and severe abrasion thereof which would otherwise occur, due to the heat in both the blank I and the tube 4 passing thereover. In order .to' further reduce the friction between the bore 4 of the tube 4 and the outside surface I9 of the tube bore mandrel II, a rotatably mounted sleeve as described before in connection with Fig. 16, but of modified form, having the same outside surface diameter as the outside sur face I9, may readily be placed upon a suitable shank integral with the rear portion of the mandrel II and occupying the space between the two grooves I99 and I91 (the latter grooves being dispensed with in that event) and held against endwise movement on the shank by means of a locking nut screwed onto the shank at the forward end of the latter up to the forward end of the rotatably mounted sleeve and h d by means of a pin against unscrewing, the locking nut also having a circular cylindrical portion of the same diameter as. the outside surface I0 adjacent to the sleeve, and a forward end portion tapered to form a conical end the same as the forward conical end 99. The lubrication of the rotatably mounted sleeve being provided for the same as for the solid mandrel II, by means of a lngs mounted on longitudinal bore in the shank with drilled holes of the bore of the sleeve. and

groove on the outside surface rotatably mounted sleeve men tioned above, consist of: A series of roller bearthe outside diameter of the bearings'bein'g the same as thesleeve diameter to permit therollers to contact rollably-with the shankand with; the

bore 0 of the tube l; or ofa series of roller bearings, having outer rings with the sameoutsidc diameteras the sleeve, mounted on theshank in place of the sleeve, the outside surface of the rings contacting with the bore 6 of the tube 4and the rollers with'the shank;for a series'of plain rings, mounted on the shank inplace of the sleeve,

having the sameoutside surfacediameter as the sleeve and bore of the same diameter as the shank, the outside surface contacting with the boreS of the tube 4and the, bore rotatable on the shank. The lubrication of these roller bearings and plain rings being provided for the same as for the sleeve. The sleeve and the roller bearings and plain rings being suitable for cold worked tubes chiefly. Where the bore 6 of the tube .4 is

of non-circular cylindrical form,. the rotatably mounted sleeve, as described before in .connection with Fig. l6, having the outside surface conforming totherequirements of the bore 6 andof the same cross sectlonal form and dimensions, is mountedon a stationarily held. shank integral with the rear conical end 96 and extending for i the full lengthequal to the length of the outside surface I0 ofthe tube borelmandrel II, the locking nut on the forward end of the shank in this case having merely the form of the forward conical end 02. The rotatably mounted sleeve thus rotating freely about the longitudinal axis 23-23 a of the pass on the shank held stationary by Thesleeve 205 has a circular cylindrical outside In Figs. 25-26-27 is sh wn outside surface 200 to the mandrel rod as. The large end of the two conical ends 96 and 03, in this case, must be smaller in diameter than the smallest lateral dimension of the outside surface of the ,rotatably mounted sleeve in order to avoid interference withithe non-circular cylindrical .bore 0 of. the.

tube 4. The mandrel locating and holding sleeve 85 must be modified to resemblethe sleeve 205 s'eenin Fig. 25, without the eye-lever I51 and other projecting parts which, would prevent rotation thereof with the rotatably mounted sleeve mentioned above, andmust also have abore 94 of the same lateral sectional form and dimensions as the outside surface of the. rotatably mounted sleeve.

the longitudinally movable tube bore mandrel 202, having an hexag-J onal cylindrical surface 203, than the tube 4 made thereover, the blank I being shown loosely fitting thereon. The shank 204. of circular cylindrical form, is coaxially integral with mandrel 202 at the forward end of the latter, and has the mandrel locating and holding sleeve 205 removably tightly slidably mounted thereon.

surface 206 of the same diameter as the outside surface 5 of the tube 4; each pass of the tube 4 through'the machine, of course, requiring a differentsleeve 205 having a different suitable diameter of the outside surface 206,,the successive passes of the tube 4 requiring thediameter of the cessively smaller. For each pass of .the tube 4 through the machine, the machine must be reset era 9 to suit the smallest (or the shank in place of the sleeve, mercial work there will be a tubes 4 in prolecting from the greater in length be correspondingly sucas described, including a diil'erent tube guide bushing II with a smaller diameter bore I2. By grinding the tuberolling faces 0 of the disk rollfinished) diameter of the outside surface 0 of the tube 4, no grinding ofthe faces 0 will be required for the passes prior to the last (or finishing) pass. In practical comlarge number of mandrels. 202,, in fact equal to the number of most cases, and the .number of the setting-up operations will be greatly reduced by rolling large lotsof tubes 4 for each setting of the machine The length of shank 204, and of the mandrel locating in a stripping machine in the samejmanneras in the past. To facilitate ready removal of the tube.

4 where the borei is of unusual, form, and" not otherwise removable in the usual manner by withdrawing longitudinallythe mandrel 202from the beret of the tube 4, the mandrel 202 may be I made longitudinally sectional of a number of-segmentallongitudinal pieces mounted to be securely held in place on a central longitudinal shank integral with the shank 204 and extending coaxially rearwardly from the latter, so that release of the segments from the central shank will permit withdrawing the shank from within the bore .of the segments, and then the segments one at a time from within the bore 8 of the tube 4. l rezam 111201'1!settirt r-up of the machine First, a set of, tour disk rollers a is selected,

of the outside surface I5 :oflthe tube 4 to be helically rolled, and mounted I Second, the tube guide on thefour spindles I4. bushing I3 is selected, having a bore I2 of the same diameter as the diameter of the outside surface s of the tube 4 tube helically rolled, and

rolled and a length equal to the width ofthe pass plus the length of the bore no: the tube is forced into the bore I2 of; the tube guide. bushing I2. and rearwardly by means of thecarriage I00 in conjunction with the sleeve; support bracket I32 in head ISI 01' the latter, similarly as explained in connection with mandrel locating and holding sleeve 05a Fourth, by individually rotating the four eccentric, sleeves II the tube rolling faces 0 of the four disk rollers 0 are brought into contact with the setting-up mandrel 24, after which the eccentric. sleeves l8 are clamped within their respective bores 25 in the spindle housing 26 in the manner described. Fifth, the setting-up mandrel is then removed from within the bore I2 of the tube guide bushing i3 by means of the carriage I 00 and thebdre I30 in head Iii of the sleeve support bracket I32, a bolt passing through a large washer on the forward side of the head III and screwed into a tapped hole in the forward end of the settingup mandrel serving to hold the latter while the and holding sleeve 205, is .equalto the length of the bore I2 of the tube bore I2 through the pass24,

and bore I30 within the pass carriage I08 is actuated rearwardly over the ways I09 by the actuating means described to pull the setting-up mandrel from within the bore I2. Sixth, the carriage I08 is then actuated over the ways I09 in the rearward direction to hold the tube guide bushing I3 in the operative position as explained, and the carriage I08 is then looked in place on the ways I09 by means of pin II4.

Seventh, the forward tubular blank guide bushing 32 is selected, having bore 40 suitable for the diameter of the outside surface 2 of the tubular blank I from which the tube 4 is to be hellcally rolled, and secured in place within the central bore 36 and counterbore 38 in the spindle housing 26 as explained. Eighth, the rear tubular blank guide bushing 51 is selected, having bore 66 suitable similarly as bore 40 of the bushing 32 in the seventh step, and secured in place within the bore SI and counterbore 63 in the tubular extension hub 49 as explained.

Operation of the machine with longitudinally stationarily held tube bore mandrels First, the tube bore mandrel II is selected. having the circular cylindrical outside surface I0 of the same diameter as that of the bore 6 of the tube 4 to be helically rolled, and a mandrel rod 88 of greater length than the tubular blank I from which the tube 4 is to be made, and placed on the grooved rollers at the rear of the machine as explained and rolled into position in the ma,- chine, as seen in Fig. 7. Second, the mandrel locating and holding sleeve is selected, having a circular cylindrical outside surface 91 and bore 94 of the same diameter as the outside surface 5 and the bore 6 of the tube 4 respectively, and, with the mandrel rod88 and the tube bore mandrel II securely held against endwise movement by means of the two retaining collars 89 at the rear end of mandrel rod 88 in engagement with the support bracket yoke 90, is forced into place within the bore I2 of the tube guide bushing I3 and over the forward end extension of the outside surface I0 of the tube bore mandrel I I, by means of the actuation of the carriage I08 over the ways I09 and employing the bore I30 in the head I3I of the sleeve support bracket I32 as an abutment for the forward end hub I29 thereof as explained. The carriage I08 is then looked in place on the ways I09 by means of the pin II4, with the tube guide bushing I3 in the operative position. Third, the support bracket 92 and yoke 90 are then actuated out of engagement with the retaining collars 89 at the rear end of mandrel rod 88, to permit the tubular blank I to be passed over the mandrel rod 88 and into the machine in the forward direction until the forward end of the blank I is in contact with the conical faces I of the four disk rollers 9, the grooved rollers at the rear of the machine facilitating handling of the tubular blank I and entering same into the machine. The support bracket 92 with yoke 90 is then again actuated to permit the yoke 90 to engage the two retaining collars 89 of the mandrel rod 88 and hold the latter coaxial to the longitudinal axis 2323 of the pass 24, as seen in Fig. 7, the rear end of the blank I being clear of the collars 89. Fourth, pressure lubricant is then provided for the tube guide bushing I3 and the tube bore mandrel II and the four disk rollers 9, the lubricant being oil for cold worked tubes and water for hot worked tubes, as explained. Fifth, the operator then turns on the power to the electric motor 81, by means of an electric motor control switch (not shown), to cause the gear train to be rotatably driven and to rotatably drive the four spindles I4 and the four disk rollers 9 thereby, as explained in the description of Fig. l. Rotation of the four disk rollers 9 causes the conical faces I thereof to frictionally grip the outside surface 2 at the forward end of the blank I and to simultaneously rotate the blank I about the longitudinal axis 23--23 of the, pass 24 and to feed same longitudinally forward into the pass 24 into contact with the tube rolling faces 8, as seen at the start of the tube rolling operation in Fig. 9, so that the conical faces I v and the tube rolling faces 8 thereafter jointly frictionally grip the outside surface 2 of the blank I and cause the latter to be simultaneously rotated about the longitudinal axis 23--23 of the pass 24 and to feed same longitudinally forward through the pass 24. As the, rotation and feeding of the blank I proceeds, and simultaneously therewith, the material of-the walls of the tubular blank I is progressively compressively helically rolled within the pass 24 between the tube rolling faces 8 of the four disk rollers 9 and the outside surface I0 oi the tube bore mandrel II (within the bore 3 of the blank I, and held against endwise movement by the yoke 90 of the support bracket 92, as explained) until the entire length of the blank I has been helically rolled to form the tube 4. The initial phase of the tube rolling operation is seen in Fig. 9, with the forward end of the blank I (and of tube 4) in contact with the rear end of the mandrel locating and holding sleeve 95, as displacement of the latter from within the bore I2 of the tube guide bushing I3 and from over the forward end extension of the outside surface I0 of the tube bore mandrel II begins. The progressive displacement of the mandrel locating and holding sleeve 95 is seen in Fig. 13, and the condition after displacement is seen in Fig. '7, with the results already fully described. At the end of the tube rolling operation on the blank I, the rear end of the tube 4 is even with the rear end of the bore I2 of the tube guide bushing I3, and other successive blanks I may then be helically rolled without employing the mandrel locating and holding sleeve 95, the successive tubes 4 displacing one another from within the bore I2 of the tube guide bushing I3 and from over the outside surface I0 of the forward end extension of the tube bore mandrel II successively, and serving to locate and hold the tube bore mandrel II longitudinally coaxially within the pass 24 in the same manner as the mandrel locating and holding sleeve 95. The procedure in removing the tube 4 from within the bore I2 of the tube guide bushing I3 and from over the forward end extension of the outside surface l0 of the tube bore mandrel I I, is to clamp a hinged split collar over the outside surface 5 of the tube 4 at the forward end of the tube guide bushing I3 and then actuate the carriage I08 forwardly over the ways I09 to withdraw the bore 8 of the tube 4 from the mandrel II, the hinged split collar (not shown) is next clamped onto the outside surface 5 of the tube 4 at the forward end of the bore I30 in the head I3I of the sleeve support bracket I32 and the carriage I08 actuated over the ways I09 in the rearward direction to withdraw the outside surface 5 of the tube 4 from within the bore I2 of the tube guide bushing I3. The tube 4 is supported on the series of grooved rollers at the front end of the machine, as explained. For the greatest accuracy, the mandrel locating

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