US2060779A - Method for making rolled hollow metal articles - Google Patents

Description

Nov. 10, 1936. c. G. STEELE ET AL METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES Filed Dec. 9, 1951 5 Sheets-Sheet l .Zwswmaas Nov. 10, 1936. c. G. STEELE ET AL METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES Filed Dec. 9, 1951 5 Sheets-Sheet 2 wx lHH iin rzzzwz'azas 1 31 Sraazs 77H 5'15 wsws' mm? q,

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METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES Filed Dec, 9, 1931 5 Sheets-Sheet 3 Nov. 10, 1936.

'c. G. STEEILE ET AL METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES 5 Sheet s-Sheet 4 Filed Dec. 9, 1951 Wis-4x72 47125 55: 525525 WHISJZBVEJVS BY W M JIIUJPNEYS.

Nov. 10, 1936. TEELE ET A 2,060,779

METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES 5 Sheets-Sheet 5 Filed Dec. 9, 1931 55 Mayra-1.22s

5. WWW w J y E UNITED STATES PATENT OFFICE METHOD FOR MAKING ROLLED HOLLOW METAL ARTICLES Charles G. Steele and Walter H. Stevens, Los Angeles, Calif.

Application December 9, 1931, Serial No. 579,888

5 Claims.

Our invention relates to an apparatus and method for transverse rolling of metal articles, preferably hollow metal articles, between a plurality of rolls, which rolls, during the rolling op- 5 eration have their axes at fixed distances apart. In this type of rolling there are usually two rolls which may be considered as supporting or form rolls, these generally having a configuration to fit the finished article. With these two supporting rolls there cooperates a forming or pressure roll. This pressure roll has a segment cut out, a convenient manner being to have this with a flat side, such flat side forming a chord of the roll, and the articles to be rolled are inserted between the two supporting rolls and the forming roll while this flat or non-operative surface is located above the supporting rolls. The articles may then be inserted transversely to the set of rolls or inserted longitudinally of the axis of the rolls. In this type of rolling a single rotation of the pressure roll gives a complete, finished article.

Our invention relates principally to rolling hollow blanks without a mandrel by which not only the outside but the inside diameter may be re- 25 duced and thus retaining a wall thickness in even the most reduced parts substantially equal to that of the original blank at these particular parts.

Another feature of our invention relates to using a pair of supporting rollers having a complementary configuration to that of the finished blank and rolling the articles transversely by means of a forming or pressure roll which has a general spiralled cam-shaped increase in radius to force a reduction of the blank and then terminates the rolling with surfaces of constant radii.

A further feature of our invention is that the blank is rotated a comparatively large number of times or turns on the supporting rollers which are of relatively small diameter compared with the pressure roll for one rotation of the pressure roll and during the action of the last section of the pressure roll the radii at various places are constant.

In this type of rolling apparatus and in the method of operation, one of the objects of our present invention is to .provide adjustment for the various rolls to simultaneously regulate the distance apart whereby when the pressure roll is lowered. to roll comparatively small articles, the two supporting or form rolls are brought together, but the arrangement is always such that the axis of the form roll is vertically above the mid distance between the axes of the two supporting or form rolls. This control or adjustment of the relative position of the rolls also separates the supporting or form rolls when the pressure roll is elevated to accommodate articles of larger diameter. The ratio of vertical movement of the pressure roll to the lateral or horizontal movement of the supporting or form rolls is so related that the articles undergoing the rolling are adequately supported while being reduced by the pressure roll. This is accomplished by the simultaneous vertical movement of the pressure roll and the lateral to and from movement of the two form or supporting rolls.

Another object and feature of our present invention is employing in the pressure roll a cam or series of cam surfaces for reducing the article to be treated as distinguished from the eccentric type of reducing surfaces or sections of the pressure roll. The cam construction allows a gradual reduction of the article under treatment with a gradual pressure being brought to bear on the article by the pressure roll. By the cam construction of the reducing sections of the pressure roll, pressures which would distort the finished article or jam the machine may be avoided.

Another object and feature of our present invention relates to the rolling of hollow articles in such a manner that these may have diiferent sections considered longitudinally reduced in different degrees or in different shapes but maintaining the wall thickness substantially constant. In other words, by our invention, tubular blanks of substantially a constant wall thickness or of different wall thicknesses at various parts may be rolled transversely, changing the configuration to conform with that of the finished article in one turn of the pressure roll and in which the wall thickness of the finished article is substantially the same as that of a similar section of the blank. By our method of rolling, a reduction in diameter of the article causes an extension of its length.

Another object and feature of our invention relates to a clutch which is automatically operated to stop the pressure roll at each rotation with the fiat side down for withdrawing the rolled article and inserting a new blank. Together with this clutch we incorporate a manual control which will allow the clutch to be retained in driving position to continuously drive the pressure and the supporting rolls.

Our invention is illustrated in connection with ,the accompanying drawings, in which:

Fig. 1 is a side elevation of our invention taken in the direction of the arrow I of Fig. 2;

Fig. 2 is a plan taken in the direction of the arrow 2 of Fig. 1;

. Fig. 3 is an end elevation taken in the direction of the arrow 3 of Fig. 1;

Fig. 4 is a partial elevation in partial section of one of the housings for the rolls;

Fig. 5 is a horizontal section on the line 5-5 of Fig. 4 in the direction of the arrows;

Fig. 6 is a vertical section on the line 5-5 of Fig. 1 in the direction of the arrows;

Fig. '1 is a section on the line 'I--'I of Fig. 1 in the direction of the arrows;

Fig. 8 is an elevation of a blank;

Fig. 9 is an elevation of a finished article;

Fig. 10 is a diagram to illustrate a reducing roll having a cam reducing surface. the cam surface being exaggerated relative to the diameter of the roll;

Fig. 11 is a diagram illustrating prior attempts to use an eccentric reducing surface on the reducing roll, the eccentric being exaggerated relative to the diameter of theroll.

In the drawings, referring first to Figs. 1 and 2, I employ the reducing roll stand II, a gear drive II, a main clutch 13, a reducing transmission gear i4, and an electric motor l5 as a source of power. The drive gears connect the rolls by spindles It.

The reducing roll stand, the transmission gears I 2, and the reducing gears l4, are illustrated as mounted on longitudinally extending tracks H,

which are firmly secured to the floor IS. The reducing roll stand is constructed with two end pedestals I! which have lugs 20 at the opposite sides for bolting the tracks I! and each of these has internal vertical guides 2|, an enlarged lower opening 22, and a horizontal guide base 23 for the lower rolls. A head piece 24 is mounted on the sides 25 of the ends of the stand. The pressure roll-23 has end axles 21 which are mounted in sliding bearings 23. This is formed in the manner of a split bearing having a lower half section 23 and an upper half section 30. There are guide plates 3| which hold these bearing sections in position in the guide 2|. The lower supporting or form rolls 32 each have axle ends 33, these being mounted in a horizontally slidable bearing block 34, which blocks are open at the top and are arranged to slide transversely on the base 23 and are guided by side plates 35.

The gear drive l2 has a pair of pedestals 36 also connected to the tracks II. In the pedestals there is a central drive gear 31 which has an axle 33 extending through the housing and being journaled therein in any suitable manner and .having one element 39 of the clutch. The gear 31 meshes with two lower gears 40 and M, these each having their own shaft suitably journaled in the pedestal 35. A large or upper gear 42 has its own, 'shaft also Journaled in the pedestals. Thus the drive is communicated from the driving shaft 33 through its gear 31 to the gears 40 and 4| at the bottom and also to the gear 42' at the top. The shaft carrying the gears 40 and 4| and also the shaft carrying the gear 42 are connected by spindles to the shafts of the form roll 32 and to the shaft of the pressure or formingrnli 25, thereby communicating the drive to the rolls. The reduction gear mechanism need not be described in detail as it is not part of our immediate invention, except to state that this has a power transmission shaft 43 on which is slidably mounted the second element 44 of the clutch I3. As the drive from the electric motoris constant and the clutch element (is constantly driven, therefore, when the clutch is engaged it rotates the rolling gears and on disconnection these gears become stationary.

The general shape of the ripper or pressurein the direction of the arrow 49. The roll is designed to first obtain a pressure engagement on a cylindrical object to be worked at substantially the center of the roll and a pressure exerting portion is formed as a cam 50. This cam has a starting end 5| from the cylindrical portion 48 of the roll. The cam gradually merges so there will be no abrupt pressure brought to bear on the article to be rolled. The final stages of this cam section indicated at 52 are made on the radius 53, this having the center 45 so that the article at the center has a finished cylindrical rolling after being pressed inwardly or reduced to the desired extent. The particular configuration of the roll is dependent on the articles to be manufactured.

In Fig. 8 a hollow cylindrical blank is indicated at 53. This is indicated as having a wall thickness 54. Fig. 9 illustrates a finished article 55, in this particular instance being an axle blank and having a tapered section 56 with a long taper, an opposite taper 51 at the end, these tapers diverging from the line 58. The opposite end 59 has a cylindrical section illustrated as of the same diameter as the blank with the inclined shoulder 60 adjacent thereto. Therefore, to form an article of this type the pressure roll will have a cam-shaped pressing center which will engage the blank 53 at about its center and reduce this to form the taper 56. This reduction gradually elongates the metal of the blank so that the finished article is longer than the blank. The reducing pressure forms the tapered shoulder 60. In the present instance the portion 59 is left substantially the same diameter as the blank initially used. The end taper 51 is also formed by a cam-shaped surface 6i on the pressure roll which commences its action subsequent to the pressure at thecenter so that the elongation is substantially fully accomplished before the end section 6! is started. The operation is such that it leaves a constant thickness wall 62 when rolling hollow articles. This wall is substantially of constant thickness provided its thickness was the same in the original blank because the reduction of the tubular blank does not increase or decrease materially the thickness of the wall but causes an elongation lengthwise which accommodates the displaced metal forced from the center, usually in both directions.

The supporting or form rolls 32 are formed with a surface configuration designated generally at 63. This configuration is such as to accommodate and support the finished article; and in the illustration given requires an enlargement 54 to accommodate the shoulder portion 60 of the article and an enlargement 65 at the end to accommodate the contracted end 51 of the article. It is obvious that the pressure and supporting rolls will be changed in their configuration in accordance with the article to be rolled and that the pedestals of the roll stand may be placed further distance apart for the mounting of longer or shorter rolls. The articles to be rolled may'be entered between the rolls from one side while as is used in the art. The headpieces on each side of the machine are connected by a top bar 68 which is illustrated as being in the form of a channel having a web 81 and two flanges 88 (note Fig. 6). This rigidly secures the two pedestals of the roll stand spaced proper distances apart. If the distance is to be changed the top bar must necessarily be elongated or shortened. In the center of each head bar 24 there. is a central bore 89 in which is fitted a bushing 10, this having a flange II at the bottom and is bolted in place by bolts I2. This bushing is threaded, and extending therethrough are the thrust screws 13. These thrust screws have a conical enlargement 14 adjacent the top forming a thrust bearing for the complementary conical bearing I5 in the ends I8 of the transverse beam 11, this beam extending across between the two pedestals and being supported on each of the thrust screws. The lower end I9 of the thrust screw bears in a thrust socket 19 in the upper half 30 of the bearing 28. Four adjustable tension rods 80 extend from the end I6 of the beam 11 and engage below the bottom half 29 of the bearing 28. These are tightened sufficiently to give a proper fit to the bearing on the end shaft 21 of the pressure roll. It will thus be seen that the weight of the pressure roll when there is no work being operated upon is carried by the thrust screws" to the beam 11 and from the end 16 of this beam the rods 80 support the bearing 28 and thus suspend the pressure roll.

The manner of operating the pressure roll to raise and lower'this comprises an electric motor 83 mounted in the center of the beam 11 and driving shafts 94 extending in opposite directions from the motor. These shafts extend through bearings 88 also mounted on the beam I1 driving a beveled gear 88 (note Figs. 5 and. 6)

The beveled gear 88 meshes and drives a complementary beveled gear 81 on a transverse shaft 88 which extends along cross arms 89 mounted I on the ends of the beam 11 and extending over the pedestals having the journals for the rolls. This shaft has bearings 90 in this cross arm. It is provided with a worm 9| which meshes with a worm wheel 92 on the spindie end-93 of the thrust screw I3, thus rotating this screw. One direction of rotation threads the screws 13 on both sides of the roll stand downwardly and thus lowers the pressure roll to the proper position on the work, the upward thrust in rolling being taken by the threads on the thrust screws and in the bushings 10.. Conversely, when the thrust screws are rotated in the opposite direction to raise the pressure roll the rods 80 lifting on the lower section of bearing of this roll elevate the roll. v

The drive to separate or to thrust together the supporting or form rolls is as follows, having reference particularly to Figs. 1 through 6. At-

each side of each pedestal there is a vertical divided shaft 94 with splined connecting sleeve 94' journaled at the top 95 in the cross arm 89 and at the bottom in a journal 98 extending outwardly from the lower part of the pedestal. At the upper end each of these shafts carries a worm wheel 91 which meshes with a worm 98 on the outer ends of the cross shaft 88. At the bottom of each vertical shaft 94 there is a beveled gear 99 which meshes with a beveled gear I00 each splined to a transverse screw IIlI. This screw is journaled in a journal bracket I02 on lugs 20 at the lower portions of the pedestal I9. Such screws operate through a threaded bushing I03 in each leg of the pedestal. They have enlarged heads I04 which fit in the sockets I05 in the bearing blocks 34 which form the bearings for the axle shafts of the lower, that is, the form or supporting rolls. Therefore, in one direction of rotation of these vertical shafts 94, the screws IOI are threaded inwardly and thus thrust the bearing blocks 34 toward each other, bringing the supporting or form rolls closer together and in I this same action the center and upper pressure or reducing roll is lowered. Conversely, in a reverse direction of the shafts 94 the screws IOI are withdrawn outwardly, thus separating the hearing blocks 34 and the lower rolls mounted therein and simultaneously the thrust screws 13 are threaded upwardly, causing the elevation of the upper roll. It' will thus be seen that the three rolls which coact together in rolling and reducing articles are simultaneously separated and brought together and the proper gear system may be chosen and pitch of all of the screws so that the vertical distance between the lower rolls and the upper pressure and reducing roll bears a correct relation to the horizontal distance between the two lower supporting or form rolls.

The movable clutch element 44 is as follows, having reference particularly to Figs. 1 and 2:

A pair of journal blocks I08 are each secured to the rail I1 and may be adjusted therein longitudinally of such rail. Journaled in these is a rock shaft I0'I extending transversely from one block to -the other, which rock shaft has a rocking lever I08 connected thereto. This lever has a sliding link I09 connected thereto, the upper part II 0 of which is pivoted to the lower part. The free end III has a pin thereon which is adapted to engage a projecting pin II2 of a cam type on the shaft on the upper gear 42. The arrangement-is designed whereby when the flat side of the roll 26 is opposite the lower rolls the cam pin engages the pin on the end III of the link and raises this. A yoke H3 is connected to the rock shaft I01 and connects with a collar II4 fitted on the clutch eement 44. Therefore, when the link I09 is pulled up through the action of the pressure roll the clutch element 44 is disengaged from the clutch element 39, thus allowing the gears and hence the drive to come to a stop. It is necessary to reset the clutch manually, which is done by the following mechanism:

An elongated rock shaft H5 is mounted in journals IIS on the floor, and this has a series of vfoot pedals III extending outwardly from the machine. A lever II8 connects to the rock shaft and the link II9 leads to the rocking lever I08. Springs I20 underneath the foot pedals and engaging the fioor tendto elevate these pedals, causing a thrusting upwardly on the link II9, thus rocking the lever I08 down and disengaging the clutches. This action pulls down on the link I09, the upper portion IIO of which has a cam I20A, which engages with a cam I-20B, on the pedestal 38, and thrusts the pin III outwardly. This upper end is normally retracted by a spring I20C. This action causes the pin 0 to clear the cam pin H2 and allow the manual resetting of the clutch. Then if the pedal is not held down the drive will be continuous and this is of use where articles can be removed and inserted between the rolls at each rotation. There is suflicient slip connection between the various links and levers to allow the manual setting and continuous operation as well as the intermittent operation.

One of the features of our invention, as above mentioned, is that the reducing portion of the pressure roll is formed in the manner of a cam and, of course, if there are a number of difierent portions of the article to be reduced in diameter, there will be a plurality of these cams. We use the cams in contradistinction from the prior art in which attempts have been made to use eccentric reducing surfaces. The cams are usually formed somewhat in the manner of a spiral with the smallest radius being at the initial point of grip on the work and the point of maximum radius being that at which the reducing operation is completed on the work. Following this the pressure roll usually has a cylindrical section whose radius equals from the axial center of the roll to the point of maximum radius of the cam.

In Fig. 10 we illustrate in diagram a form of the pressure roll 26. In this case the center 45 is the axial center of the roll on which it rotates.

.41 is the radius from the center to the initial starting point of the grip of the roll. The roll rotates in the direction of the arrow 49. In this case the cam 50 is illustrated as having its initial working surface start at substantially adjacent the part 48 which is substantially cylindrical. The cam gradually increases in radius from the center 45 and, in fact, may be made somewhat in the form of a spiral having the radius gradually increase from the radius of the circle of the roll to the maximum required for the reduction of the work in hand. The final portion I 2| of the cam is indicated as having the radius 53 and the remaining portion I22 of the rolling surface as having a radius I23, this portion being a cylindrical section. It will thus be seen that by this construction of cam the cam surface is greater than 180 and gives a gradual increase in radius without dipping inside of the circle formed by the radiusof the roll at its place of smallest diameter. This circle is indicated dotted at I24.

Referring to Fig. 11, the axial center of the roll is designatd at I25. This has a flat side I26 and in this instance the radius to the point I21 of the initialgrip on the work is indicated as of the same radius "as that of the roll having the cam. In this case an eccentric rolling surface is illustrated having a center I28 which, as will be seen, is offset from the center I25 and an eccentric curve I29 would illustrate the shape of such a reducing surface. It will be noted that this surface for a portion I30 is inside of the portion I3I of the circle having the radius 41 at the center I25. The remaining portion of this circle is indicated dotted at I32. It will, therefore, be seen that the eccentric crosses the line of the circle substantially at the point I33. If this type of roll is used the initial point of the grip on the work is represented by the part I2! of the roll which is of greater radius than the portion I30 from the center I25. Therefore, there would be a release in pressure on' the work while the roll turned without having effective action on the articles being operated upon. The pressure would then suddenly be brought to bear on the work substantially at the point I33 of the roll and thus would increase to the maximum at the point I34, which is on the radius I35 of the eccentric. The portion I36 is indicated as having a radius I3'I with I25 as the center. It will, therefore, be seen that when the cam reducing surface is used there is a gradual and increased pressure being brought on the work being handled, giving a continuous reduction in diameter of this part. This tends to elongate the article. With the eccentric construction a portion of the surface of the roll does ineffectual work and then a more or less sudden pressure with a, rapid reduction is brought on the work. This causes an ineffectual rolling of articles rolled transversely by.our procedure. We are under the impression that the camshaped reducing roll is one of the factors which enables us to roll tubular blanks having cylindrical exterior and interior surfaces with a constant thickness in such a manner that this blank may be reduced in diameter at various portions to the desired extent and that the finished article will have substantially the same wall thickness as the original blank at both the reduced and nonreduced sections. The metal which is displaced in reducing the diameter is forced lengthwise of the article and thus elongates such article.

On account of the supporting rollers being of quite small diameter compared to the forming or pressure roll the blank is given quite a number of turns or rotations for one rotation of the pressure roll to operate on the blank as various sections of constant radii designated I23 (Fig. give the blank what might be termed a cylindrical rolling during the final stages of the operation. The portion of the pressure roll having the constant radii I23 is suflicient to give at least one complete rotation to the blank. The wall thickness of the finished blank at any particular section is maintained substantially equal to that of the original blank at this section because the blanks are reduced by rolling without a mandrel. The supporting rollers have a configuration complementary to that of the finished blank and at every diametrical section the radius is constant. Therefore, as the forming or pressure roll which has a spiralle'd cam-shaped increase in radius as it rotates presses the blank to change the exterior configuration to be complementary to that of the supporting rollers but as there is no mandrel on the inside of the blank the metal of the blank meeting no resistance at the parts which are reduced is pressed inwardly. If the reduction in diameter of the blank is very great the pressing inwardly of the inside portion of the blank does not quite take care of the reduction so that in such there is some elongation of the blank but this is taken care of by the design of both the supporting rollers and the pressure roll.

An important feature of our invention in rolling hollow blanks without a mandrel is that the inner skin of the blank is not injured or distorted nor is it cut away or pressed in any manner. Therefore, this inner skin does not materially lose in strength in the rolling operations as the fibres of the skin are more or less undisturbed.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined in the appended claims.

We claim:

1. The method of rolling hollow blanks without a mandrel, rotating a blank on its axis without bodily displacement of the blank and at the same time applying pressure in a radial direction on the blank, the pressure gradually increasing taining the wall thickness of the finished article substantially the same as the original wall thickness of the blank at corresponding diametrical sections.

2. The method of rolling hollow blanks without a mandrel having a circular periphery and of substantially a constant wall thickness at any diametrical plane, comprising rotating the blank on its axis without bodily displacement of the blank and gradually exerting pressure radially inwardly of said blank, said pressure increasing until the blank is reduced to a predetermined radius, said rolling elongating the blank to form the finished article but leaving the wall thickness of the finished article at any diametrical plane substantially the same as that of the blank at the same plane.

3. The method of transverse rolling hollow blanks without a mandrel having a circular periphery at different diametrical sections, comprising supporting the blanks on form rolls having a peripheral shape to conform to the finished article and having circular working surfaces, and exerting a pressure in a radial direction on the blank by a pressure roll having a camshaped pressure surface formed somewhat as a spiral, the pressure roll completing the rolling in one complete rotation, said blanks having their diameter reduced at the sections acted upon by the cam of the pressure roll, the wall thickness of the finished article and the blank being substantially the same for corresponding parts, the finished article being elongated in amount varying with the reduction in diameter, and in the rolling retaining the blank without bodily longitudinal displacement.

4. The method of rolling hollow blanks without a mandrel, comprising supporting a blank on a pair ofspaced supporting rollers having a configuration complementary to that of the finished article, exerting a radial pressure on the blank to force the exterior of the blank into the configuration of the supporting rollers, the pressure gradually increasing while the blank rotates a plurality of times, and then finishing the blank by a circular rolling without increase of pressure whereby the interior of the blank is reduced in diameter at various portions simultaneously with the exterior of the blank to maintain sub stantially the original wall thickness at various diametrical sections, said radial pressure increasing in proportion with constantly increasing radii of the pressure roll from its axis. a

5. The method of rolling hollow blanks without a mandrel, comprising rotating a blank on its axis without bodily displacement. of the blank and at the same time applying pressure in a radial direction on the blank, the pressure gradually increasing to continually change the radius of parts of the blank under deforming pressure while the blank rotates a number of times, said pressure changing the diameter of different portions of the blank considered longitudinally thereof, then finishing the blank by a rolling at least one complete rotation of the blank without reducing pressure, whereby the interior diameter of the blank at various sections is reduced while the exterior is reduced, and the original wall section at the corresponding sections remaining substantially constant, said radial pressure increasing in proportion with constantly increasing radii of the pressure roll from its axis.

CHARLES G. STEELE.

WALTER H. STEVENS.

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