US1210895A - Apparatus for and method of corrugating metal tubes. - Google Patents

Description

L, H BRINKMAN. APPARATUS FOR AND METHOD OF CORRUGATJNG METAL TUBES.

'APPLICAIION FILED OCT. 15. 1914.

ATTORNEYS Patented Jan. 2,1917.

4 SHEETS-SHEET lmmsga v L. H. BRINK MAN.

APPARATUS FOR AND METHOD OF CORRUGATING METAL TUBES.

APPLIQATIONFILED 00115. 1914.

ill" IN Patented Jan. 2, 1917.

4 SHEIETS SHEET 2.

' v ATTOR YS L. H. BRINKMAN. APPARATUS FOR AND METHOD OF CORRUGATING METAL TUABESK APPLICATION map OCT. 15. 1914.

. Patented Jan. 2, 1917. A

4 SHEETS-SHEET 3- t 3 R k I I ATTORNEYS L. H. BRINKMAN. APPARATUS FOR AND METHOD OF CORRUGATING METAL TUBES.

APPLICATION FILED OCT. 15.1914.

' Patented Jan. 2, 1917.

M 4 SHEETSSHEET 4.

am-$14 flu 011401 0 nua w foz i helically corrugating LOUIS H. BRINKMAN,

OE GLEN- RIDGE, NEW JERSEY, ASSIGNOR, BY

an sraarns aarniaa ent re MESNE ASSIGN- MENTS, TO BALTIMORE TUBE COMPANY, INCORPORATED, A CORPORATION OF VIR- GINIA.

APPARATUS FOR AND METHODOF CORRUGATING METAL TUBES.

Specification of Letters Patent.

PatentedJan. 2, 1917.

Application filed October 15, 1914. Serial No. 866,758.

To all whom it may concern Be it known that I, LOUIS H. BRINKMAiy, a citizen of the United States, and a resident of Glen Ridge, county of Essex, State of New 'Jersey, have invented certain new and useful Improvements in Apparatus for and Methods of corrugating Metal Tubes,- of which the following is a specification.

- My invention relates to apparatus for and method of corrugating metal tubes.

The invention is especially useful for hot metal tubes. I have'her'etofore provided apparatus. for

helically corrugating tubes, such apparatusbeing the subject matter of United States Letters Patent Number 1,120,269 for tube- 'corrugat1ng apparatus, granted on December 8, 1914, upon an application filed by me on January 11, 1913, Serial No. 741,390. The apparatus of said patent is very efiicient in corrugating cold tubes, but it produces a very heavy twisting force in the metal being folded which, to a very considerable extent, twists the metal as it is being folded to aid in folding it. But I have found that hot tubes can hardly stand the twisting force produced in the tube by the use of said machine when used for deeply corrugating tubes. '80 that one of the objects of this invention is to provide a durable and eflicient machine that can be used to form very deep helical corrugations in hot metal tubes. The machine is capable of corrugating tubes Without subjecting the metal being folded to such a severetwisting force as takes place in the operation of my said other machine, and the tubes corrugated by the present machine are not twisted to the extent to which they are twisted by the other machine. When the metal is hot it can be folded or corrugated without twisting it to the extent to which it is desirable to twist cold tubes in corrugating them, and, furthermore, as stated, the hot metal will not stand so great a twisting force.

Another object of the invention is to proof which corrugated tubes of considerable length and having extremely deep corrugations, may be made, the lengths of the'corrugated tubes being limited only by thelengths of the tubes obtainable to be corrugated.

A further object of the invention is to' provide a method of corrugating metal tubes, and especially hot metal tubes.

In order that my invention may be more readily understood and further objects of the invention more fully appear, I will first describe a machine for drawing hot metal tubes embodying the present preferred form of my improvements in tube-corrugating apparatus and by the operation of which my preferred method of corrugating hot tubes may be carried out. V

In the accompanying drawings illustrating said machine, Figure 1 is a longitudinal elevation of the machine; Fig. 2 is a top plan view of the same; Fig. 8 is an end elevation of the left-hand end of the machine looking in the direction of arrow A; Fig. 4 is a sectional elevation taken on line 1- 1 of Fig. 2; Fig. 5 is an enlarged longitudinahsection taken on line 5 5 of Fig. 1; Fig. 6 is a cross-sectional view taken on line 66 of Fig. 5; Figs. 7 and 8 show details; Fig. 9 is a view taken on line 99 of Fig. 1; Fig. 10 is a section taken on line 10-10 of Fig. 9; Fig. 11 shows a tube being corrugated; and Fig. 12 shows anenlarged side elevation of a portion of the machine shown in Fig. 1,

with certain of the parts in section.

the guideway, so that the' carriage may move back and forth thereon. The table is provided with end brackets 6, 6 in which is mounted a main drive shaft 7 driven at the right-hand end of the machine by any suitable means, such as a pulley 8. This main drive shaft 7 is geared to a swaging apparatus hereinafter referred to, carrying the corrugating tools, to rotate the same, and is also geared to the carriage 1 to move the same along the track, each as follows: The said shaft 7 is provided at its left-hand end with a gear 9 keyed to rotate therewith,

meshing with a gear 10 mounted on a hollow spindle 11 (Fig. 5) j ournaled in a frame 12 and carrying at its other end the corrugating tools of the swaging apparatus hereinafter referred to. Also keyed to the end of the shaft'7 adjacent the gear 9 is a beveled pinion 13 which meshes with beveled pinion 14 mountedon a stub shaft j ournaled in bracket 15, the stub shaft being provided at its other end with a beveled pinion 16 meshing with another pinion 17 keyed to a worm shaft 18 mounted in a suitable bracket 19 below the trackway and having a worm 20 which drives a worm wheel 21 keyed to a threaded or leadshaft 22. This lead shaft extends through a threaded nut 23 (Fig. 4) mounted in the lower end of the carriage 4, so that as the threaded shaft 22 is rotated through the above-mentioned gearing, the carriage is moved along the trackway.

The main shaft 7 also drives a rotating chuck 24 to which the forward end of mandrel 59 and tube 60 are secured by set screws 61, 61., The chuck is rotated in the same -'directionas the corrugating tools of the swager, but at a different rate. In the present machine the chuck is driven at a greater rate of speed than the tools. To'rotate the chuck the shaft is provided with a keyway extendingva'long its length, in which slides a key 25 secured to agear 26 which, through the intermediation of pinions 27 and 28, drivesgear 29 loosely mounted (Figs. 9 and 10) on a sleeve 62 keyed to stub shaft 63 journaled in bearings 30, 30 on the carriage. The pinions 27 and 28 are also journaled on the carriage in bearings formed in the vertical webs 31, 81 of the carriage. The stub shaft 63 is provided with a nut and washer 64 in engagement with the bearing 30' to take the drag of the tube secured to the chuck 24 on the other end of the stub shaft. The gear 29, and'sleeve 62 are connected through springs '67 secured at one end to the gear and at the other end to projections 68 from the sleeve. The gear is also provided with lateral projecting lugs orstops 69 and 70 serving to limit the movement of the sleeve relative to the gear. The object of this connection is to permit the chuck toi vield at certain times, as hereinafter explained.

In order that the gear 26 will move'along the shaft 7 as the carriage is moved back and forth, the vertical webs 31, 31 (Figs. 2, 4 and 10) are each provided with bearings or sleeves 32, 32 surrounding the shaft 7, one on each side of the gear 26. By means of this arrangement the gear 26 is made to followthe movements of the carriage, and at the same time is caused to rotate' with the shaft 7 to drive the rotary chuck 24. v

Referring to Figs. 5, 6 and 8 showing the construction of the swaging. apparatus can rying the corrugating tools; it will be seen slotted out to provide guides for any desired number of corrugating tool sections. In the present machine the head isprovided I with two cross slots at right angles to each other so as to provide four .guide sectors 37,

as, 39, 40 (Fig.8) acting as guidesfor the. i f

. tool sections 41, 42, 43, 44 s'lidingly mounted between the adjacent sectors so that they may move in and out radially therebetween.. r

In order to hold the tool sections in place,

an annular ring 45 '(Fig. 5) is provided which is held in place by suitable bolts 46 (Fig. 6) extending into the guide sectors of the head 36. 40 are provided with shoulders 52 cooperating' with shoulders 52 on. the tool sections to limit the outward movement of the tools due to the centrifugal force thereon. The frame l2sur'rounding the head 36 is provided with an enlarged annular recess 47 in which is mounted an annular frameior'ring 48 on the inner surface of which rollsl50 run. These rolls may bereferred to as cam rolls and they are journaled in .two F.1d

rings 51, 51 which'serve to tie the rolls together. The rings 51, 51 and the rolls 50 carried thereby are driven around in ring 48 by engagement of the curved outer ends The guide sectors 37 to of the tool sections with the rolls 50 asthe tool sections are rotated, so that thejrjglls' 50 run around on the inner surfaceiofglifig 48 at a rate considerably less than 'fihe-"ratQ' of rotation of the tool sectionsysomething less than half the rate.

\V hen the spindle 11 is rotatedthea" sections are thrown outward by centrifugal force against the shoulders 52, and as theysimultaneously engage the cam rollers they are momentarily forced inwardlywliile under the rollers, and then thrown out again), by the centrifugal force, etc., so that they are continuously and rapidly recipr'ocated as the spindle is rotated. The inner ends of the tool or die sections'are tapered as shown at 53 (Fig. 6) to permit of the desired radial movement of the sections, and the inner ends of the sections are provided with projections 54 to 58 which, when the die sections are as sembled, form a thread-or helical projection increasing in height and decreasing in pitch toward the finishing end of the die. preferred form of the invention as shown herein (Fig. 5), the projections formed in each section of the die or tool constitute longitudinal sections of a. continuous'thread or helical projection progressively increasing in height and decreasing in pitch, so that In the when the die is assembled, the projections of thedifierent die sections form such a helical projection.

It will be observed that the helical die teeth or projections are so constructed that the advance projection 54: simply initiates 1n the tube a helical mark ,or groove along which the tube is to be folded, and that the advance convolutionof the helical projection marks out along the length of the tube sufficient metal to form the axial sectional configuration of the desired fold in the ultimate product; that is, the distance along the groove between the adjacent points 5+Land 55 is equal to the distance along the groove between the points 57 and 58, and equal to the distance between any intermediate sue-- cessive points. The forward end of the tube before being placed in the machine is drawn down slightly tapering, the extreme end of the tube fitting the mandrel 59 to which it is secured. The taper of the tube at this end is preferably substantially equal to the taper Q of a line connectingthe projections of the .chine as a whole hereinafter.

die sections. It will be observed in Fig. 5 that such line tapers inwardly toward the finishing end of the die. this arrangement is to have the rear convolution or convolutions bring the metal at the end of the taper firmly down on the mandrel so as to start corrugating the tube at this point by'corrugations of gradually increasing depth, but of regular pitch, so as not to unduly strain and distort the tube at the commencement of the operation, the forward projection of the die gradually engaging the tube from there on.

The operation of the die sections to corrugate the tube will be more readily understood by describing the operation of the ma- The rear end of the tube rests upon a series of grooved rollers 38, 33 mounted'on a frame 65, the tube being laid loosely on these rollers, and extending through a gas furnace 66 and through the die to the rotary chuck 24.

, If the chuck is rotated at 500 revolutions a minute to drive the tube at that rate, and the sw nger carrying the tools at too revolutions a minute, the tube will rotate once relative to the tools for every four revolutions of the tools, and since the swager is provided with four cam rolls rotating at say 130 revolutions per minute (something less than half the rate ofthe tools), there will be a relative rotation of 270 revolutions per minute between the tools and the rolls. The tools will therefore deliver 2.7 blows, or, in

other words, grip the tube 2.7 times for each.

rotation of the swager, so that the tube will be gripped and released 10.8 times for each complete rotation thereof relative to the tools. The lead screw is preferably geared so as to movethe tube forward a distance equal to the distance between the last two present form The object of teeth of the die for each rotation of the tube, in other words, to cause the tube to travel in-conformity tool helix.

In order to prevent the mandrel 59 from becoming unduly through whi h it passes, and in order to also with the pitch of the v heated by the furnace cool the corrugated or completed portion of the'tube as it is formed on the mandrel, I provide suitable means for conduct ng a cooling cooling fluid mandrel and cause it to flow back through the mandrel. In Fig. 12, I show a meanso fluid into the mandrel, and the" of the invention, I convey the to the forward end of the accomplishing this, which consists of a pipe 73 supported in any suitable rigid support or clamp 74 and extending through .the mandrel to its forward end where the pipe is turned upward slightly at its forward end to provide a nozzle for discharging the water into the mandrel, from whence the water flows rearwardly and is discharged at the rear'end of the mandrel. The rear end of the pipe 73 is coupled up by any suitable coupling, such as a piece of flexible tubing 7 5, with any suitable source of water supply represented by pipe 76. r j

The operation of the machine is as follows: The forward end of the tube 60isrun into the furnace and the, water supply. pipe 73 is then inserted in the mandrel secured in its support 7 4, andcoupled up to the water supply, and the water turned on;

After the tube 60 has been heated sufficiently, it is pushed through the die and the forward tapered end secured to the end of the mandrel by set screw 61. The tube having been secured in this manner, and

its rear end resting on the rollers 33, 33, the machine is started upj-whereupon the chuck is rotated through the above-mentioned yieldab-le connection with gear wheel 29, the sectional dies are rotated by spindle 11, and the carriage commences to move forward due to the rotation of lead shaft 22. At this time the rear or finishing projection of the' tool sections is in alinement with the end of the tapering portion of the tube, as shown in Fig. 5, and as the spindle 11 rotates, the tool sections are rapidly reciprocated, as heretofore explained, producing a rain of hammer blows upon the tube, the sections gripping the tube momentarily each time they are moved inward by the cam rollers, and releasing it momentarily each time they are thrown outward by centrifugal force after passing the rollers. The sections thus continuously act to momentarily grip and release the tube, and as the tube is fed forward by the lead shaft, the convolutions which are being formed in the metal by the gripping action of the sectional-dies, are gradually screwed along the gradually deepening helix of the die section, increasthe tube being sired finished fold.

through the guiding .ends of the tool ing in depth and decreasing in pitch so as to fold the metal deeper and deeper as the tube is acted upon by the die sections and rotated forward. The advance projection of each section serves to produce a slight indentation along the tube in a helical line,

i and as the tube is fed forward, that'portion of the corrugation which had been acted on by the advance convolution of the die gradually moves through the succeeding convolutions, being momentarily gripped andreleased until it reaches the final convolution of the die having the contour ofthe dedrel to momentarily lag behind the positively driven member of periods, and to be the moments of release. tubeis relieved of the enormous twisting force that would'occur if the dies were always'in engagement with the metal or if it were attempted topoSitively rotate the tube during the moments that it is gripped by the die; This operation is continued until the entire tube has been corrugated, heated by the furnace as it is drawn through'the same. It is advisable, if not necessary, tubes in this manner, to cool the die or tool sections, and for this purpose I deliver,

through passage 49 extending through frame 12 and ring 48 a cooling fluid to the recess 47 in whicha sufiicient depth of water or other cooling fluid is maintained to cool the die sections as they rotate through the same. By regulating the amount of water fed to the recess at? through the passage 49 the water may be-kept below the die sections so only by conduction that they are cooled parts, or it may be kept at such depth as to permit the outer sections to dip into the water as they rotate, the centrifugalforce throwing the water outward from the hot .tube so as not to interfere therewith, and any water thrown off in this manner will flow down the sides of the-ring 48 into the bottom of the recess and out through the opening 72 made for that purpose.

It will be seen from the above description that my preferredmethod of corrugatprocess of corrugating -v1ous to those skilled in standing my lnvention,

ing hot tubes, which. consists in alternately and momentarily gripping and releasing the tube along a helical line at a progressively shifting short length of the tube, may be carried out by this machine.

While I have described with particularity the preferred embodiment of my improveinents in tube-corrugating machines and tubes,it Will be obthe art, after underthat various m0difi It will now be seen. 'that the object of the resilient connection to the chuck is to permit the tube and manthe chuck during tubes,

1n operating upon 110tcations and changes may be made therein without departing from the scope or spirit of the invention, and I aim in theappended claims tocover all such changes and modifications.

Having thus described my invention, What I claim as new and desire to secure by Letters Patent, is

1. In .a machine for corrugating metal tubes, the combination of means rotative relative to the tube for momentarily gripping the tube along a helical line and releasing it .one or more times successively during each relative rotation between the tube and said gripping means to in the tube, and means for rotating said gripping means.

.2. In a machine for corrugating metal the combination of means for rotating the tube, rotative means for momentarily and successively gripping the tube along a helical line and releasing it aplurality of times during each rotation of the tube to form corrugations in the tube, and means for rotating said gripping means relative to the rotating tube.

3. In a machine forcorrugatingmetaltubes, the combination of means rotative' relative to the tube for momentarily gripping the tube along a helical line and releasing it one or more times successively tive rotation between the tube and said gripping means to forn'i-corrugations in the tube, means for rotating said gripping means, and means for producing relative longitudinal movement between the tube and the gripping means.

I. In a machine for corrugating metal tubes, the combination of means for rotating the tube, means continuously operating to momentarily and successively grip the tube along a helical line and release it to'form corrugations therein, means for rotating said gripping means relative to the rotating tube, and means for producing relative longitudinal movement between the tube and the gripping means.

5. In a device for corrugating metal tubes, the combination of a plurality of radial recipro-atory tool sections each provided atits inner end with a longitudinal section of a helix having a plurality of convolution's, means for rotating said. tool sections relative to the tube to be corrugated, and means cooperating with said sections to cause them to be reciprocated when rotated to momentarily grip and release the tube being corrugated.

6. In a device for corrugating metal tubes,

the combination of a plurality of radial reciprocatory tool sections each provided at'its inner end wlth a longitudinal section of an internal thread having a plurality of convoform corrugations tions relative to the tube to be corrugated, and means cooperating w th sa1d sections to cause them to be simultaneously reciprocated' when rotated to momentarily grip and release the tube being corrugated;

T. In a machine for corrugating metal tubes, the combination of a swager having rotative adially' arranged tool sections, each tool section having a section of a helix formed on its inner end, saidsection s of the helix forming, when assembled, a helix increasing in depth and decreasing in pitch for mo tinuous relative rotation and longitudinal movement between the tube and said gripping means. I

9. In a machine for corrugating metal tubes,'the combination of means for continuously acting upon the tube to alternately and momentarily grip the tube along a helical line andrelease it to form corrugations therein, means for producing relative rotation' between the tube and the gripping means, causing a twisting force in the finished portion of the tube, and a smooth mandrel extending beyond the gripping means and through thefinished portion of the tube and of substantially the size of the inner diameter of the folded tube, upon which the tube is folded by the gripping means to protect the folds of the finished tube from distortion due to the twisting force.

10. In a machine for corrugating metal tubes, the combination of means for momentarily and successively gripping the tube along a helical line and releasing it to form corrugations therein, means acting upon the finished end of the tube for producing relative rotation between the tube and said gripping means, said gripping means acting to grip and release the tube one or more times during the formation of each convolution, and a smooth mandrel extending from said rotation producing means and ,upon which the tube is folded to protect the finished folds from distortion due to twisting.

having formed on its inner and a l0ngitudinal section of a helical projection decreasing in p1tch, means for contmuously rotating and reciprocating said tool sections radially w to cause them to continuously act to momen tarily grip and release the tube along a helical line, means for producing continuous relative rotation and longitudinal -movement between the tube and said gripping means, and a mandrel of substantially the size of the inner diameter of the finished tube upon which the tube is folded by the gripping means 12. In a machine for corrugating metal tubes. the combination of means for rotating the tube, a smooth mandrel secured to said means and to which the tube is secured at 1ts ducing relative rotation between the tube and'sald tool, and a smooth mandrel extending from the finishing end of the machine to the gripping means for protecting the folded tube, said mandrel being substantially the size of'the inner diameter of the finished tube. a

14. Ina machine for corrugating metal tubes, the combination of means for momentarily and successively gripping a tube along a helical line and releasing it to form corrugations therein, means for producing relative rotation between the tube and said gripping means, said gripping means acting to grip and release the tube one or more times during the formation of each convolution, means at the intake end of the gripping means for heating the tube, a hollow man drel upon which the tube is folded by the I gripping means, said mandrel being of substantially the size of the inner diameter of the finished tube, and means for cooling said mandrel.

15.In a machine for corrugating metal tubes, the combination of means for continuously acting upon the tube to alternately and momentarily grip the tube along a helical line and release it to form corrugations therein, means at the intake end of the grip ping means for heating the tube, a hollowmandrel upon which the tube is folded by the gripping means, and means for conveying a cooling fluid into said hollow mandrel to cool it. I

1 -1 a machine for corrugating metal tubes, the combination of means for continuously acting upon the tube to alternately and momentarily grip the tube along a helical line and release it to form corrugations therein, means at the intake end of the gripping means for heating the tube, means for rotating the forward end of the tube-relative to said gripping means, a hollow mandrel secured to said rotating means and to which the forward end of the tube is secured, said mandrel extending from the finishing end of the machine toward the gripping means, and means for clrculating a' cooling fluid through said mandrel to cool the same. f

1.7. In a machine for corrugating metal tubes, the combination of means acting continuously to momentarily and successively grip the tube along a helical line and release it to form corrugations .therein, and means for producing relative rotation, between the means having a resilient connection which tube and said gripping means, saidrotationproducing means' including a yieldable connection.

18. In a machine for corrugating metal tubes, the comblnation of means for continuously acting upon the tube to alternately and momentarily grip the tube along a helical line and release it to form corrugations therein, and means for rotating the tube rel-' ativeto the gripping, means, said rotating will momentarily yield when the tube is gripped by the gripping means'and will move the tube forward during the moments of release.

1 9. In a machine for corrugating metal tubes, the combination of means'for continuously acting upon the tubeto alternately and momentarily grip the tube along a helical tubes, thecombination ofarotary sectional corrugating tool having a plurality of recip rocating tool sections acting continuously to momentarily and successively grip the tube along a helical line and release it to form corrugations therein, means for rotating said sectional corrugating tool relative to the tube to be'corrugatedand-means cooperating with saidztool sections to cause them te be reciprocated whenrota'ted to momentarily grip and release the tube being corru-- gated. I

21. In a machine for corrugatingmetal tubes, the combination of a corrugating tool ,7 having a plurality of reciprocating tool 'sections adapted toact continuously to momentive thereto to cause them to reciprocatein their guides and means for rotating the tube relative 'to the sections during the reciprocations.

. tarily and successively grip the tube along a helical line and release it to form corruga- 4 tions therein and having a member with guides in which said reciprocatingtool sec- 3 tions are mounted, means operativelyl' re:

. lated to said tool sections and rotativerela;

22. In a machine for corrugatin 'Inetal tubes,'the combination of a corrugatlng tool .having a plurality of reciprocating tool sec-" f tions adapted toact continuously to momen tarily and successively grip the'tube along a' helical line and release it to form corrugations therein and having a member with guides in which said reciprocating tool sections are mounted, means operatively related to said tool sections and rotatrve relat1ve thereto. to cause them to reciprocate-in their guides and means for rotating the tube relative to thesections during" said reciproca tions, said means, including a mandrel extending to the tool sections and to which mandrel the finishing end of the tube islse cured, the diameter of said mandrel being substantially 23.'In a machine for corrugating metal equal to the inner diameterrof the corrugated tube. 1

tubes, the combination of a rotary sectional corrugating tool having a plurality of'reciprocating tool sections acting contlnuously to momentarily and successively .grip vthe tube along a ing said sectional corrugating tool relative to the tube to be corrugated, means cooperating with said tool sections to cause them tobe reciprocated when rotated to momen-j' tarily' grip and release the tube being corrugated and means for rotating the tube comprising a mandrel extending through the sectional tool and to which the forward end- 1 of the tube is secured, the diameter of said mandrel being that of the inner diameter of the finished tube.

24. In a device for corrugating metal volutions, means for rotating said tool/sec.-

tions relative to the, tube to be corrugated, -means cooperating with said sections tohelical line and release ittoform corrugationstherein, means for rotat- .tubes, the combination of a plurality ofradial reciprocatory tool sections each pro- I vided at its inner end with a longitudinal section ofa helix having a plurality of con-- cause them 'tobe reciprocated when rotated I to momentarily grip and release the tube belng corrugated, means for heating the tube, and means for conyeying a cooling fiuid'to the toolsections to cool'them.

25. The method of corrugating 'metal y hich consists in acting upon the'tube I to alternately and momentarily grip it along a helical line of progressively decreasing pitch and release it, while simultaneously g ipping means.

heiicul line of d veiy shifting 51w imtei y leasing a progressively shite of the hot tube along a hehc 1 creasing pitch.

' icing oizt-ive rotation hetween the "Ian method of corrugeting 10h cons1sts 1n alternately d 1220-- g ripping and *QiHSlRg ntire.

s rin es 27.

28' The method of com ting meta which consists heafi nit iately and mom-enariiy pping anci eleasing the tnbe along a hello 1 line of deuree ing pitch a piiogi'es iy shifting r8101"; length of the tube and protecting the oonvoiutions of the finished tube frorn disiortion.

In testimohy Wk? name to this speoih of two subscribing wn T. have signeci my 1n the presence Eswm SEGER. v

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