US2442850A - Method of and apparatus for making flat metal tubes - Google Patents

Description

June 8, 1948. L. G: GLESMANN 2,442,850

METHOD OF AND APPARATUS FOR MAKING FLAT METAL TUBES Filed Dec. 20, 1943 3 Sheets-Sheet l Invenifow L 6.616 M m v June 8, 1948. 1.. G. GLESMANN 2,442,850

METHOD OF AND APPARATUS FOR MAKING FLAT METAL TUBES Filed. Dec. 20, 1943 3 Sheets-Sheet 2 .1; 11267111 12121 WWO R mwrmm bk .lIl'lIl-ll v m. mw

in ir June 8, 1948. 2,442,850

METHOD OF AND APPARATUS FOR MAKING FLAT METAL TUBES L. G. GLESMANN 5 SheetsSheet 3 Filed Dec. 20, 1943 Patented June 8, 1948 METHOD OF AND APPARATUS FOR MAKING FLAT METAL TUBES Louis G. Glesmann, Rome, N. Y., assignor to Revere Copper and Brass Incorporated, Rome, N. Y., a corporation of Maryland Application December 20, 1943, Serial No. 515,034

11 Claims. 1

My invention relates to apparatus for and methods of making flat metal tubes.

The invention, which has among its objects a method of making such tubes particularly adapted to be practised by rolling operations, will be best understood from the following description when read in the light of the accompanying drawings of examples of the method and apparatus for performing it, while the scope of the invention will be more particularly pointed out in the appended claims.

In the drawings:

Fig. 1 is a plan of the right hand portion of apparatus according to the invention with parts broken away;

Fig. 2 is an elevation of the portion of the apparatus according to Fig. 1;

Fig. 3 is a plan of the left hand portion of apparatus according to the invention with parts broken away, being a continuation of the apparatus partly shown by Fig. 1, the fragments of the gear and grooved roll shown at the extreme right of Fig. 3 being part of the same gear and grooved roll shown at the extreme left of Fig. 1;

Fig. 4 is an elevation of the apparatus according to Fig. 3 with parts broken away;

Fig. 5 is a section on the line 5--5 of Fig. 4 on an enlarged scale with parts in elevation;

Figs. 6, '7 and 8 are, respectively, sections on the lines 66, 1'! and 8-8 of Fig. 3 on an enlarged scale;

Fig. 9 is a section on the line 9-9 of Fig. 4 on an enlarged scale with parts omitted;

Fig. 10 is an elevation according to Fig. 9;

Fig. 11 is a schematic diagram of the gearing according to Figs. 1 to 4;

Figs. 12 to 16 are, respectively, sections on the lines l2-l2 to iii-l6 inclusive of Fig. 2 on an enlarged scale;

Figs. 17 to 22 are, respectively, sections on the lines l'l-l l to 22-22 inclusive of Fig. 4 on an enlarged scale; and

Fig. 23 is a section corresponding to Fig. 21 showing a tube of modified cross-section.

Heretofore seamless tubes of flattened crosssection have been formed from tubes of circular cross-section by use of a plug die, that is to say, by drawing the tube of circular cross-section through a die opening and over a plug positioned in that opening, the die opening and plug having respectively the cross-sectional shapes of the exterior and interior surfaces of the flattened tube. Commonly it is necessary to perform the drawing operation in two steps, the first consisting of a rough drawing operation and the second a finished drawing operation. Likewise it is necessary when drawing the tubes to preliminarily straighten the tube of circular cross-section before it is drawn so as to secure a straight flat tube, it being impossible for such tubes when they are of rather small cross-section and of thin gauge to be straightened on account of the straightening operation buckling the tube Walls. Still further, because of the necessity of supporting the plug employed in the drawing operation on a rod which projects beyond the end of the seamless tube being operated on the length of flat tube that can be formed is rather limited.

According to the present invention, flattened seamless tubes are formed by a rolling operation preferably starting with the tube of circular cross- 7 section, the invention being particularly applicable to tubes of relatively small size and thin gauge. For example, but without limitation thereto, a copper tube of circular cross-section having an outside diameter of 0.5 inch with a wall thickness of 0.05 inch may be operated on to produce a flattened tube of the cross-section shown in Fig. 21 about 0.75 inch wide outside and 0.09 inch thick outside.

By practice of the present invention it is unnecessary preliminarily to straighten the tube of circular cross-section, being operated on, while the flattened tube, produced in a single pass through the apparatus, is uniformly straight and of uniform cross-section. Further, the only limitation on the length of the tube that may be produced is determined by the length of the tube constituting the starting material. Still further, the tubes can be produced vary rapidly, say at the rate of about feet per minute, as compared to the rate at which they may be produced by drawing operations.

In the embodiment of apparatus shown by the drawings a table I (Figs. 1 and 2) is provided of sufficient length to support the tubes 3 to be operated on, which tubes before being operated on are, as shown, of circular cross-section. Adjacent the table is a support 5 carrying a guide I for the tubes. As shown (Figs. 1, 2 and 12), this guide comprises an elongated member having a slot 8 so formed as to provide walls 9 adapted to engage with the exterior lateral walls of the tube, the top of the slot being open so that the operator may readily place the ends of tubes in the slot and push them toward the first of the series of cooperating rolls hereinafter mentioned. Conveniently, the guide 1 is detachably secured to the support 5 as by removable stud bolts 'll so that 12 to the oval cross-section illustrated in Fig, 16.;

As best illustrated in Figs. 13, 14, 15'and16, the peripheral lengths of the openings formed-by the pairs of cooperating grooves .transverse to the tube are greater than the circumference' of;

the tube, so that the extreme edge portions of the grooves do not operate on the extreme edge portions of the tube. Were these peripheral lengths of the grooves less-than the circumference of the tube the walls of the oval tube would be locally crumpled, On the other hand, were such lengths substantially the same as the circumference of the tube, the walls of the oval tube at one side of its major medial plane would be liable to be offset from its walls at the opposite side of that plane because of the practical impossibility of insuring that the groove in one roll will be exactly in registry with the groove in its cooperating roll. The existence of local crumpling of the tube wall or of offsets in it may result in splitting or weakening of that wall when the tube is operated on further to flatten it, and in any event will cause objectionable malformation of the tube.

7 Asa result of the above operation, the bends at opposite edge portions of the oval tube formed by the rolls I3, l5, l1, I9 are such that those edges are rather pointed, these bends being sharper than is suitable for producing the bends desired at the edges of the finished tube when the oval tube leaving the rolls I9 is subjected to the tube flattening operations hereinafter described, the overall efiect of the rolls [3, I5, I! and l9-in this respect being analogous to that which would be secured at the edge portions. of an oval tube if formed by passing a tube of circular cross-section between a single pair of cooperating" fiat rolls, which latter, like the rolls illustrated, also would not operate on the extreme edge portions of the oval tube.

Were the flattening operation continued by passing the tube leaving the rolls [9 between flat rolls, or rolls having grooves of the desired shape of the finished tube, that desired shape would not be secured, the opposite edge portions of the flattened tube in such case being overfiattened in the sense that such edges would make a sharper bend than desired, and it has been found that this would be true even if a series of pairs of rolls were provided gradually to flatten the tube leaving the rolls [9. 'To avoid this defect the machine shown is provided adjacent the driven rolls"!!! with a pair of cooperating idle rolls 23 positioned transverse to'the rolls l9. These rolls 23 are provided with peripheral grooves 25 which operate on the opposite edge portions of thefiattened tube to remove the above mentioned sharpness of the bends at those edges, so as to increase the radii of curvature of those bends to such extent that operating on the tube in the manner hereinafter described will result in a flattened tube having edge portions of the desired curvature. It will be observed from a comparison of Figs. 16 and 17 thatthe. edgerolls 23 secure this result by bendingthe tube walls at the opposite edges of the oval to spread apart the opposite flattened walls of the tube between those edges, the resulting curvatures at such edges being greater than those of the final finished tube. From one aspect the operation performed by the edge rolls 23.may be said to be that of blunting the edges of the oval tube leaving the grooved rolls I9.

- After the tube leaves the edge rolls I! it, according to the present invention, is operated on adjacent the center portions of its flattened sides further to decrease its thickness and further flatten those sides. In this way a minimum of bending oi isuch nature as will act to point the opposite edges of thetube will occur, so that in the final tube the edges thereof will be bent approximatelyon arcs of circles and the sides of the tube will" be substantially flat across their full widths to the tube edges.

To the above ends, in the machine shown the tube after leaving the edge rolls '23 passes between the cooperating driven flat rolls 3|, then between the pairs of cooperating crowned idle rolls 35 and 37 the profiles of which, as viewed in Figs. 3 and 5, are shown as arcs of circles, and finally between the cooperating driven flat rolls 45 The rolls 3!, 35 and 31. are adapted to contact with the center portions of the opposite sides or faces of the tube presented to them and act gradually to fiattenthose sides and to decrease the tube thickness, while the rolls act to size'the tube and remove any irregularities initsfiattened sides. Best results will be secured by having the rolls 3'! at their crowns spaced apart but slightly more than the rolls 45 so as to cause no'more working of the tube by the latter than is necessaryto size the tube and cause proper operation of the tube straightening means hereinafter described.

The spacing between the rolls 45 ordinarily should be very slightly less than the desired thickness of the finished tube to compensate for spring in such tube, customarily, however, such spring will not amount .to much more than about 0.01 inch. By reason of the rolls 3|, 35 and 31 acting at the center portions of .the sides of the tube presented to them excessive bending at the edge portions of the tube is avoided as above explained, the shape imparted to the edge portions by the edge rolls 23 being such as to cause such bending as occurs at the edge portions after the tube leaves the edge rolls to result in the edge portions of the finishedtube being approximately arcs of circles after the tube is operated on by the rolls 45, .which latter cause the plane flattened side surfaces of the "tube to extend to the edges defined by these arcs.

Further, pressing the sides of the oval tube toward each other by acting on them adjacent the minor axis of the oval tends to bow outwardly portions of the tube walls'between that axis and the tube edges, and to avoid such bowing of the walls, and thus make them approximatelyfiat, the arcs defining theprofiles of the crowned rolls are made rather flat so' as to minimize such bowing, it being observed'that an excess tendency of the. walls to bow outwardly will be obstructed by the surfaces of the crowned rolls opposite where the bowing tends to occur. The radii of curvature of these arcs of the surfaces of the crowned rolls is not critical however so long as it is sufficient to prevent material bowing of the walls constituting the sides of the tube .beyondthe limit ofthe spring of those walls, thus to cause the sides 'of' the tube to be approximately fiat, because the sizing rolls 45 will remove any slight irregularities in the sides of the tube presented to it. In Figs. 19 and 20 these arcs, for convenience of illustration, are shown of smaller radius than commonly would be used in practice. In practice in making a tube of the dimensions mentioned arcs of about 5 inches radius will give satisfactory results.

It will be understood that in making a tube of the shape shown in Fig. 22, although each of the rolls I3, I5, IT and I9 is shown as grooved, the final rolls IQ of this group of rolls may be flat rolls, and in some instances even the intermediate rolls I5. Also in many instances four pairs of rolls need not be employed in this group, but a lesser number, and in some instances it may be necessary to employ a greater number of rolls. Likewise in some instances the flat pair of rolls 3| may be omitted, and in some instances but one pair of crowned rolls need be employed. These considerations will depend upon the wall thickness of the tube being operated on and the temper of such wall.

It will also be understood, that because of the spring in the tube walls, the cross-section of the tube after leaving a given pair of rolls commonly will not be exactly the same as when it is between those rolls. For example, the walls of the tube after the latter leaves the rolls 3i commonly will spread apart at its minor axis so that the sides of the tube will not be fiat as shown in Fig. 18. This effect is particularly noticeable as the tube passes toward the final rolls, because as it passes through the machine it becomes progressively work hardened and its spring increases. However, as above mentioned, this spring will seldom amount to but more than 0.1 inch measured transversely of the tube. Because of the spring in the tube varying with the wall thickness, shape, size and material of the tube, in practice, if it is necessary frequently to make tubes having varying characteristics in these respects, the various pairs of rolls may be conveniently mounted for adjustment of their axes toward and away from each other in any of suitable well known ways. commonly employed for that purpose in rolling mills so that the spacing of the rolls may be readily adjusted by trial to suit the characteristics of any particular tube being produced.

Leaving the rolls 45 the tube passes through the guide indicated in its entirety at 41 (Figs. 4, 9 and and then onto the top of the table 49 (Fig. 3) being guided over the latter by the guide strips 5 I.

The guide 41, as best shown in Figs. 9 and 10, comprises a pair of spaced upstanding rigid members 53 carried by a plate 55, which plate is secured to a fixed bracket 51 by studs 59 passing through a slot 6| in the plate so that the members 53 may be adjusted properly to position them relative to the path of the tube 3, and so that diflerent plates 55 and members 53 may be substituted to accommodate difierent sizes of tubes, the bracket 51 being carried by the support 5. The guide members 53 are positioned adjacent the bite of the driven rolls 45 at the exit side thereof. Any tendency of the tube to deviate edgewise from a straight line will cause one or the other of the two edges, depending upon in which direction the deviation tends to occur, to bear against one or the other of the guide members and hold the tube against such deviation while the rolls 45 are working it, As a result of this the tube passes from between the guide members 53 perfectly straight in so far as edgewise out of straightness is concerned. Conveniently, to insure retention Of the tube between the guide members, the same are preferably bridged by a plate 58.

The guide strips 5|, which are removably secured to the table 49 so that guide strips may be employed spaced the proper distance apart to accommodate the width of the tube, restrain the tube from passing over the table 49 otherwise than in a straight line, and thus act to insure that the tube in passing over the table will not be accidentally bent.

The pairs of rolls I3 to I9 which work the tube to deform it from its circular cross-section to an oval cross-section act to level the tube, that is to say, remove any unstraightness that may exist in the tube originally presented to the apparatus. The rolls which subsequently act upon the tube maintain this straightness in so far as fiatwise out of straightness of the tube is concerned, while the guide 41, as above explained, insures that the finished tube will be straight ,edgewise.

It will be observed that the several driven rolls progressively act upon tube portions of progressively decreasing thickness. Consequently, these rolls tend to place the tube under slight lengthwise tension, and thus avoid buckling the tube. The rolls however do not elongate the tube, the finished tube being substantially the same length as the tube presented to the apparatus. Any difference in the speed at which the several driven rolls tend to move the tube is compensated forloy.

slippage between the tube and the rolls. Preferably the driven rolls are of the same diameter and rotate at the same speed, or are otherwise of such diameters and rotate at such speeds as will cause the portions of the tube between adjacent pairs of rolls to be under slight tension.

The various rolls may be supported and driven in any suitable way. As shown (see Figs. 1, 3 and 7), the support 5 is provided with bosses 63 in which are rotatably supported shafts 55, the latter having tapered ends 61 on which the rolls are removably mounted by means of the nuts 59 and washers I I, so that different rolls may be substituted to accommodate tubes of different dimen sions. Opposite the rolls the projecting ends I3 of the shafts in any suitable way rigidly carry meshing gears I5 for driving cooperating rolls of pairs of rolls at the same speed in opposite directions. Also carried by the support 5 are idle gears Ii which mesh with adjacent gears I5. This arrangement of gearing will be clear from the diagram shown by Fig. 11. The train of gearing may be driven in any suitable way. As shown, in place of an idle gear between the gears 75 for driving the pairs of rolls 3| and 45 is a driven gear I9 connected to any suitable source of power. As shown (Figs. 3, 4 and 5), this gear is fixedly mounted on a driven shaft SI rotatably supported in the boss 83 carried by the support 5.

As shown (Figs. 3, 4 and 8) the idle rolls 23 are rotatably supported on studs 85 carried by a bracket 81 secured to the support 5, these rolls being removably mounted on the studs, and the bracket being removably mounted on the support, in any convenient way so that rolls of different diameter and with different grooves 25 may be readily substituted to accommodate different sizes and shapes of tubes to be formed.

The crowned rolls 35 and 31, as best shown in Figs. 3, 4 and 5, may be removably mounted on studs. 89 carried by the "support its!) that crowned i,

rollsof different diameter and shape may,- be subs: stituted. -\to accommodate diiferentrsizes: .and

shapesof tubes.

It willbe understood that, instead oi presenting a tube of circular cross-section to the apparatus,

there may be presented a tube of any cross-sec.- tion intermediate that shown by Figs; 12 to 21 inclusivain which case .onlythe rolls necessary to reduce atube of that cross-section to the final cross-section will. be employed'.- Foriexample, a

tube of cross-section shown by Fig.- 16 could be produced in any suitable way and be presented; to

the machine, in which case the rolls'indicated in Figs; 13, la and would be omitted, while aguide 7 having a slot 8 of proper-shape to accommodate the tubecould be substituted for the guide. shown.

Similarly it will be understood that the flattened tube produced by the machine need not have the cross-section shown by Fig; 21. It could, for ex ample, have the cross-section shown-byFig. 23, in which case, after the tube is brought to the,

shape shown in Fig. 19 to space apart thetube face portions at the minor longitudinal medial plane: 1.

1. Apparatus for forming flattened tubes having continuously spaced walls circumferentially thereof from tubes of circular cross-section of the same wall thicknesses comprising rolling means for flattening a tube of circular cross-section to one of continuously open oval cross-section by operation on opposite faces-of the tube without substantially operating on the edge portions of the tube adjacent the major axis of the oval, rolling means for operating on said edge portions of the open oval tube thus formed adapted to increase their radii of curvature and spread apart the faces of said tube while maintaining a tube of continuously open oval cross-section, and rolling means for operating on said spaced apart faces adjacent the minor axis of the oval adapted to flatten said faces and decrease the radii of curvature of said edge portions without operating on the portions of said faces adjacent said edge portions.

2. Apparatus according to claim 1 comprising a pair of opposed rolls between which the tube passes for sizing it after operation thereon of the last mentioned means of claim 1, guide means being provided adjacent the bite of said rolls at the exit side thereof against which one or the other of the opposite tube edges is adapted to bear upon the portion of the tube leaving said rolls tending to deviate edgewise from a straight line whereby to produce a tube which edgewise is straight.

3. Apparatus for forming from relatively thin walled tubes of circular cross-section flattened tubes havin exteriorly convex edges comprising a series of pairs of opposed complementary rolls, the rolls of at least one pair of which are formed with complementary grooves, for progressively flattening a tube of circular cross-secti0n to one of oval cross-section with-out substantially oper: ating on theedge portions. of the tube adjacent the majoraxis-of the oval, means engaging the sides'iof the .tube of circular cross-section transverse'rto the axis'of said rolls for. guiding said tube I to thegrooves; of said rolls,,means comprisinga pair of rolls positionedtransverse to the first mentioned: rolls adjacent the last of said seriesat the exit side thereof: for operatin on the edgeportions of the'oval tube thus formed forincreasing the radii of curvature of said edge per-- tions: andspreading apart the faces of said' oval tube, means comprising a pair'of opposed crowned rolls forjoperatingon said spread apart faces ad-u jacent the minor axis. of the oval for flattening saidfaces. anddecreasing the radii of curvature of saidedgeportions, means comprising a pair, of complementary. rolls for sizing the tube after beingoperated on by said crowned rolls, and op-' erativelyrigid guide means adjacent the biteof said rolls for sizing the tube at the exitside thereof opposed to each edge of the tube adapted to prevent edgewise bending of the portions of the tubevleaving said rolls.

4. Apparatus for forming flattened tubes having rounded edges and continuously spacedwalls circumferentially thereof from tubes of openoval'v cross-section of the same wall thicknesses comprising opposite cooperating crowned oval tubewith' the minoraxial line of the. oval in the medial plane of the crowns of suchrolls, and,

allowing for the spring of sai faces, ,withsaid crowns spaced apart at said plane a dlstanceinot less than the distance between the faces of the flattened tube at its edges, whereby to apply. i

rollsadapted-to operateonthe opposite faces-of the.

5. Apparatus accordingto claimA comprisinga pair of cooperating exit rolls for operating on the faces of the tube for. sizing the tubeafter be-' a ing operated "on by said'crowned rolls,.:guide: :means being provided adjacentathe bite'of saidr exit rolls against which one or the other of the opposite tube edges is adapted'to bear upon the'portion of the .tube leaving said .exit rolls' tending to deviate from a. straight line wherebyjto produce a tube which edgewise is straight;

6. The method of forming a, flattened tubeu,

havingv continuously spaced walls circumferentially thereof from a tube of circular.cross-secs"v tion of the same wall; thicknesses which .com-

prises flattening a tubev of circular cross-section to one of continuously open oval cross-section by. pressing the .tube of circular: cross-section fromopposite sides thereof. without 'substantiallyiops 4 eratingon the portions of the oval adjacentits major axis, pressing the open oval- .tubethus formed from its oppositeedges. to increase the radii of curvature of its edge portions, and subsequently pressing the tube from its opposite faces adjacent the minor axis of the oval to fiat-- ten said faces anddecrease saidradii of curvature withoutoperating on the portions of said facesradjacent said edge. portions.

'7. The method oi forming a flattened tubezhave ing continuously spaced wallsrcircumferentiallyz thereof from a' tube 'of circular .cross-sectionof the same-wall thicknesses which comprises flat-.

tening a: tube of circular cross-section to one of continuously open oval. cross-section by rolling:. the .tubeof circularqcrossesection to press its op-.: posite sides: toward each:other;:without substan;

tially operating on the portions of the tube adjacent the major aXis of the oval, rolling the open oval tube thus formed edgewise to increase the radii of curvature of its edge portions and to spread apart its faces, and subsequently operating on the tube by passing it between cooperating rolls engaging said faces adjacent the minor aXis of the oval for decreasing said radii and flattening said spread apart faces without operating on the portions of said faces adjacent said edge portions.

8. The method of forming a flattened tube having continuously spaced walls circumferentially thereof from a tube of circular cross-section of the same wall thicknesses which comprises flattening a tube of circular cross-section to one of continuously open oval cross-section by rolling the tube of circular cross-section to press its opposite sides toward each other without substantially operating on the portions of the tube adjacent the major axis of the oval, rolling the open oval tube thus formed edgewise to increase the radii of curvature of its edge portions and to spread apart its faces, and subsequently operating on the tube by passing it between cooperating crowned rolls engaging said faces adjacent the minor axis of the oval for decreasing said radii and flattening said spread apart faces without operating on the portions of said faces adjacent said edge portions.

9. The method of forming a flattened tube having rounded edges and continuously spaced walls circumferentially thereof from a tube of open oval cross-section of the same wall thicknesses which comprises pressing the oval tube from its opposite faces by forces applied thereto confined to the portions thereof adjacent the minor axis of the oval to flatten said faces and decrease the radii of curvature of its opposite edge portions without operatin on the portions of said faces adjacent said edge portions, and, allowing for the spring of said faces, without pressing said portions thereof to which said forces are applied toward each other a distance less than the distance the portions of said faces adjacent said edge portions are deformed toward each other.

10. Apparatus for forming flattened tubes having rounded edges and continuously spaced walls circumferentially thereof from tubes of open oval cross-section of the same wall thicknesses comprising means adapted to operate on the faces of the oval tube adjacent the minor axis of the oval for decreasing the radii of curvature of the edge portions of the oval, and means providing abutment surfaces opposed to portions of said faces which are between said axis and the tube edges acting to prevent excess outward bowing of said portions.

11. The method of forming a flattened tube from a tube of open oval cross-section of the same wall thicknesses which comprises pressing the oval tube from its opposite faces by forces applied thereto confined to the portions thereof adjacent the minor axis of the oval to decrease the radii of curvature of its opposite edge portions, and during the pressing operation providing abutment surfaces opposed to portions of said faces which are between said axis and the tube edges for preventing outward bowing of said portions beyond the limit of spring of the tube walls.

LOUIS G. GLESMANN.

REFERENCES GITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Certificate of Correction Patent No. 2,442,850. June 8, 1948.

LOUIS G. GLESMANN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Column 8, line 3, claim 3, for axis read axes; and that the said Letters Patent should be read With this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 10th day of August, A. D. 1948.

THOMAS F. MURPHY,

% Assistant Gammz'ssz'oner of Patents.

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