US1772538A - Method and apparatus for die rolling - Google Patents

Description

Aug. 12,-1930. wQH. DONNER AND APPARATUS FOR DIE ROLLING METHOD Filed June 4. 1927 2 Sheets-Sheet l INVENTOR Aug. 12, 1930. v w. H. DOQNNER- v 1,772,538

IE'i'HOD AND APPARATUS FOR DIE ROLLING Filed June 4, 1927 2 Sheets-Sheet 2 Patented Aug. 12, 1930 UNITED STATES WILLIAM H. BONNER, OF BUFFALO, NEW YORK METHOD AND APPARATUS FOR DIE ROLLING Application filed June 4, 1927. Serial No. 196,512.

This invention relates to the rolling of articles the cross sectional area of which varies more or less throughout their length and it particularly relates to a method of accurately die rolling such articles and to apparatus for carrying the method into efiect.

The method of forming articles of var ing cross sectional area by die rolling has een practiced for many years and has been often resorted to when large quantities of articles capable of being die rolled are required. Die rolling can only be used to advantage when the demand for the articles justifies the necessary large outlay.

It is customary in die rolling articles to roll the same in a connected series from relatively long leader bars of the proper and substantially constant cross section.

Where the die rolled articles (which are usually partially finished blanks for use in the manufacture of finished articles) are of generally circular but varying cross sectional area throughout their length, it is customary to use a leader bar of more or less oval section and of such cross sectional area as to just fill after it is reduced the largest section of the matrix portions of the die rolls.

The matrices are designed and machined or otherwise cut in the pair of rolls forming the die roll pass.

When the leader bar is reduced in cross section during rolling to conform to the matched matrices of the die rolls an. over fill or flash is (except in exceptional cases) bound to occur along opposite sides of the rolled string of blanks at all those portions which are of smaller cross sectional area than the lar est port-ion.

ne important item of expense in the die rolling of such articles as'here contemplated and in addition to the cost of the rolls is the time and laborre uired to initially set up and adjust the dra ts in the different stands of rolls necessary to produce the leader bars of proper cross section, to set up and obtain relative circumferential adjustment of the die rolls to obtain matching of their matrices as well as the adjustment of the draft of the die rolls.

Owing to this and to the fact that the die roll matrices or passes deteriorate more or less rapidly during rolling it is advisable to have in each pair of die rolls as many passes or matrices as possible in order to avoid frequent changing of rolls. Relatively long rolls, are there ore necessary in order to accommodate these multiple passes.

The diameters of the rolls used in die rolling are controlled by the lengthof the blanks to be rolled and cannot, therefore, be uniform.

In die rolling some articles it is preferable to form one article during each revolution of the die rolls while in rollin other articles, two or more articles may be ormed per revolution of the die rolls. Rolls of small diameter have a greater extrusion effect than rolls of large diameter but rolls of small diameter necessarily spring or deflect more under rolling pressure than those of large diameter. Springing of die rolls interferes more or less with the securing of accurate transverse as well as length dimensions of the rolled products and occasions variations in the thickness of the overfill or flash which is necessarily formed, when rolling articles that vary in cross sectional area throughout their length. The flash should be maintained of even thickness adjacent the body of the blank and as thin as practicable so that it can be removed to the bestadvantage.

It is, of course, necessary in designing the matrices of die rolls to compensate for roll spring and when the articles to be rolled are of varying cross sectional area throughout their length, it is necessary to take this into account 1n calculating the roll spring as the spring will vary at different points along the lengths of the-blank being rolled. The problem, therefore, of designing a die rollpass is not the simple problem encountered in designing a pass for rolling sections, of constantcross sectional area. a

In rolling circular articles in which large variations in cross sectional area occur, the roll spring encountered during rolling of the smaller sections of such articles causes the finished articles to be more or less elliptical at those smaller sections. 5

It will be understood that over fill or flash is not desired, but is a necessary evil in the die rolling in a single pass of articles of varying cross section. he over fill or flash is generally trimmed off by means of trimming dies and beside this trimming, it is generally necessary to grind off that portion of the flash which is immediately adjacent the body of the blank. The flash, therefore, should be kept comparatively thin adjacent the body of the blank because in grinding it off there is a tendency to grind a flat portion on the blank which tendency is increased if the flash is thick.

An object of this invention is to provide a method of die rolling from a leader bar of substantially constant or uniform cross section articles of varying cross section in the form of a connected series of blanks with the over fill or flash which necessarily occurs at portions throughout the length of such series of blanks as thin and as uniform in thickness adjacent the body of the blanks as is practicable in order to insure accuracy in the length and transverse dimensions of the finished blanks and to reduce the work required in the operation of removing the over fill or flash and the finishing of the blanks.

This, as well as other objects,.which will appear to those skilled in this particular art, I attain b means of the method described in the speci cation and adapted to be carried out by means of the organized apparatus i1- lustrated in the drawings and described in the specification.

In the drawings Fig. 1 is a view in longitudinal section of an organized apparatus designed for the carrying out of this method. The apparatus consists of a die roll mill provided with backing rolls of relatively large diameter, a pinion stand having a pair of pinions mounted in rigid bearing and of equal pitch diameter, drive connections between the stand pinions and the rolls and means for obtaining relative circumferential adjustment of the die rolls for the purpose of matching their matrices.

The four universal joints used in the drive connection are identical and the details of construction of these joints are illustrated in Figs. 2, 3 and 4.

Figs. 5, 6 and 7 are detail views of the means for obtaining relative circumferential adjustment of die rolls.

In carrying out this invention, I preferably utilize a pair of rolls each having a number of suitable circumferential grooves or matrices, the grooves or matrices in one roll co-operating with those in the other roll during rolling to give the proper contour to the rolled blanks.

These rolls have a constant annular velocity ratio and leader bars of the proper cross section when reduced by the rolls will form a connected series of accurately rolled articles; the number of which of course will depend upon the length of the leader bar.

In order to control or limit the deflection or spring of the die rolls which varies during each revolution of the rolls when rolling articles which vary in cross sectional area throughout their length, I oppose the vertical thrust of such rolls and I oppose this thrust immediately adjacent the forming grooves or matrices by rolls having their axes parallel to the forming roll axes, and in approximately the plane including the roll axes. I do this by mounting below the lower roll and above the upper roll a thrust opposing or stiffening roll. These two thrust opposing rolls are so mounted with relation to the die rolls that their axes lie in approximately the plane including the axes of the die rolls.

The thrust preventing rolls are merely idling rolls and are driven by frictional contact with the die rolls and being in contact with the die rolls adjacent their matrices, they so limit the deflection of the die rolls during rolling that the over fill or flash that can rarely be avoided is limited and maintained as thin as practicable and of uniform thickness adjacent the body of the blanks.

In the mill illustrated, the lower die or forming roll 8 and the upper die or forming roll 9 are provided with grooves 10 and 11 re spectively. These grooves or matrices are machined or otherwise formed of proper design in the surfaces of the rolls and by cooperating one with the other are adapted to forge a leader bar into a connected series of blanks each having the required contour and dimensions.

These rolls are relatively long and are provided with roll necks which are journaled in bearings mounted in windows in the roll housing.

Mounted in suitable bearings in the same windows and below and in line with lower roll 8 is a thrust opposing roll 12 and mounted above upper roll 9 and in line therewith is a thrust opposing roll 13. Rolls 12 and 13 are mounted in the usual manner and the ordinary means are taken to prevent their axes from crossing the axes of rolls 8 and 9.

Rolls 8 and 9 are made materially longer and in some instances smaller in diameter than the standard rolls now generally used for die rolling and a number of forming grooves or matrices as shown are cut in each roll. The deflection limiting rolls 12 and 13 prevent undue deflection in rolls 8 and 9 during rolling even though these rolls are made longer than usual.

I have shown thrust opposing rolls l2 and 13 of greater diameter than forming rolls 8 and 9, in order to make an extremely rigid roll assembly.

It will be apparent that if die rolls having a number of grooves in each roll as those shown in the drawings were utilized without limiting the spring by the backing rolls to a negligible amount there would be more spring in the die rolls when using the grooves adjacent the center of the rolls than there would when using those ad acent the roll necks. If this difference in roll snring for the forming grooves adjacent the roll necks and those adjacent the center of the roll is not taken into account in designing the roll matrices, the transverse as well as the len h dimensions of articles rolled in the di erent forming grooves will be different.

By means of utilizin the backing rolls to control the spring of tie die rolls, I am enabled to use the same calculations in laying out the matrices of all the grooves and I am tageous to drive the lower roll 8 through a enabled to roll identical articles in the different forming grooves; that is, articles havlng the same transverse and the same length dimensions. It is preferable to have the bearings for roll 12 fixed and the bearings for roll 9 adjustable so that roll 9 can bear on roll 12. The bearings of rolls 9 and 13 are adjustable and the upward movement of said rolls is limited by SCIBWfdOWIlS 14.

It will be seen that by such an arrangement of thrust opposing or stiffening rolls the undesirable but necessarilypresent over fill or flash can be kept comparatively thin and can be maintained of an even thickness adjacent the body on the blank. Such a flash can be trimmed off the blank without any-tearing or breaking effect, such as is liable to produce a rupture capable of being magnified by the 5 heat treatment, resulting in a blank of in ferior quality.

The die rolls are driven from a pinion stand having two intermeshing pinions 15 and 16 of the same pitch diameter and of the herring bone type which is preferable. The shafts 17 and 18 of the pinions are mounted in rigid bearings in the stand 19 and shaft 17 carries a gear 20 adapted to mesh with a pinion not shown, which will be driven from any suitable source of power, preferably a vari able speed electric motor. Pinion shaft 17 is connected to drive upper die roll 9 by means of a driving connection which includes a spindle 21 two universal joints 22 and 23 and a device 24 (shown in detail in Figures 5, 6

and 7) for obtaining circumferential adjustment of die roll 9 relative to pinion 15. By this means 24, relative circumferential adjustment of the die rolls can be obtained for the purpose of matching their cooperating matrices.

Lower die roll 8 is driven from pinion 16 through a spindle 25 and universal couplings 26 and 27.

Shaft 28 of die roll 8 is made longer than shaft 29 of die roll 9 in order that the universal couplings 22 and 26 can be horizontally offset or staggered as shown in Figure 1. This allows the use of relatively large universal couplings having ample bearing surfaces.

An suitable universal couplings or jointsmay e used in the driving connections so long as they have ample bearing surfaces and are constructed with the least possible play, and in Figures 2, 3 and 4, I have illustrated a well known type of universal coupling. which is suitable for use in this organized apparatus.

It will be'obvious that under certain circumstances universal couplings 26v and 27 and spindle 25 may be done away with and shaft 28 of the lower roll 8 directly and rigidly connected to shaft 18 of pinion 16.

In most cases, it is advisable and advantwo joints lie in parallel planes with the cor-- responding arms of the crosses in the same planes, I am able to obtain a constant angu-- lar velocity ratio of the die rolls.

Because of the fact that the adjustment device 24 for securing relative circumferential adjustment of the die rolls is carriedby one of the pinion shafts or in other words is .carried outside or beyond the universal joints of the driving connections, the necessary relative circumferential adjustment can be obtained while maintaining a constant angular velocity ratio of the die rolls. This device 24 can be located on either of the roll shafts 28 or 29 or on either of the pinion shafts.

While any suitabledevice may be utilized for obtainingcircumferential adjustment of upper roll 9, it is preferable to use one in which a fine adjustment can be obtained and.

in which the motion is transmitted through relatively large contact surfaces. The ad- Figures 5, 6 and 7 includes two coupling mend tion 32. A bore provided with suitable key Ways extendsthrough the hub and body portion of each coupling member to permit the member to be rigidly secured to the end of-a shaft, in one case the reduced end 33 of pin ionshaft 17 and in the other a shaft 34 formed as a part of universal coupling 23.

The two adjacent faces of the coupling members 30 and 31 are provided with sector shaped projections 35 and 36 formed respectively on the coupling members 30 and 3,1. .I

The projections of the two coupling members are spaced apart and between the radial faces thereof wedges are positioned which are movable toward and from the common axis of the coupling members for the purpose of obtaining relative circumferential adjust.-

ment of the same. This relative circumfelha to the other.

jections and the concave recesses are substantially semi-circular and offer large hearing surfaces for withstanding the stress encountered during die rolling. These semicircular bearing surfaces make it possible to arrange the outer flat faces of the two parts ofthe wedge members at different angles one In the construction shown screws 41 are employed for adjusting the wedge blocks toward and from the common axis of the coupling members. The heads 42 of these bolts are arranged within recesses within body member 31 and at their outer ends the screws are 5 uared to receive a wrench. The screws are t readed through the body portions of convex projections 40. It will be obvious that the turning of the screws will produce a radial movement of thetwo part wedges. The screws are locked in adjusting position by means of lock nuts 43.

The coupling members 30 and 31 are held together by means of bolts 44 which extend through holes in one member and slots- 45 in the othermember. Nuts 46 are provided for drawing the coupling members together and slots 45 permit relative circumferential adjustment of the two coupling members. Nuts 46 will of course be loosened to permit the coupling members to be adjusted and then tightened to hold the abutting faces of the mem-' bers in contact.

This organized apparatus having the relativel large backing rolls for the die rolls is capalile of exerting a great pressure on the leader bar without deflecting the die rolls except to a negligible extent. This allows a large portion of the leader bar to be squeezed sideways so as to produce blanks with greater differences in cross sectional areas than is possible in die rolling apparatus as heretofore constructed. 7

Having thus described my invention, what I claim is 1. The method of rolling from a leader bar of substantially uniform cross section a series of blanks, each of varying cross section,

which consists in passing between die rolls having suitable grooves or matrices formed therein a leader bar. raised to rolling temperature and in opposing the vertical thrust at approximately the section of rolling oi the cylindrical portions of said die rolls by cylindrical rolls whereby their deflection is prevented except to a negligible extent and the transverse and length dimensions of the blanks controlled within narrow limits.

2. The method of die rolling blanks of varying cross sectional area and to closely accurate dimensions, which comprises passing a leader of substantially regular cross section, and while at rolling temperature, between a air of rotating relatively long die rolls having peripheral matrix grooves varying in size lengthwise of the grooves and which grooves are spaced apart lengthwise of the rolls, and applying thrust pressure to the, die. rolls at points adjacent the grooves in use and approximately opposite the points of rolling contact with the leader to provide rolling pressure and restrict deflection of the die rolls while the leader is being operated upon.

3. The method of die rolling blanks of varying cross sectional area and to closely accurate dimensions, which comprises passing a leader of substantially regular cross section, and while at rolling temperature, beoperating matrix grooves varying in size tween a pair of rotating die rolls having cooperating matrix grooves varying in size peripherally of the rolls, and applying radial pressure to the rolls closely adjacent said grooves and approximately opposite the points of rolling contact with the leader to provide rolling pressure and prevent deflection of the rolls.

4. A mill for rolling blanks, having cross sectional areas varying lengthwise thereof, to closely accurate dimensions, which comprises a pair of relatively long die rolls having in their peripheries a plurality of cooperating matrix grooves, whose size varies peripherally of the rolls, said grooves being spaced apart lengthwise of the rolls to provide thereon a plurality of separate rolling dies, and means for applying rolling thrust to said rolls at points approximately opposite the points of rolling contact with the leader in any desired groove in which said leader is fed and closely adjacent the particular dies operating upon the leader, whereby deflection of the rolls will be reduced to a minimum and the flash maintained of even and small thickness.

-5. A mill for rolling blanks having cross sectional areas varying lengthwise thereof to closely accurate dimensions, which comprises a pair of relatively long die rolls having in their peripheries a plurality of cooperating matrix grooves, whose size varies peripherally of the rolls, said grooves being spaced apart lengthwise of the rolls to provide thereon a plurality of separate rolling dies, and a backing roll bearing on each die roll approximately opposite the points of rolling contact of the dies rolls with the leader, and closely adjacent the particular dies operating upon the leader, whereby deflection of the rolls will be reduced to a minimum and the flash maintained of even thickness.

6. A mill for rolling blanks, having cross sectional areas varying lengthwise thereof, to closely accurate dimensions, which comprises a pair of rotating die rolls having cooperating matrix grooves varying in size peripherally of the rolls, and means for applying thrustresisting pressure to the rolls closely adjacent said grooves approximately opposite the points of rolling contact with the leader to prevent material deflection of the rolls.

In testimony whereof, I have hereunto su-bscribed my name this 28th day of May, 1927.

WILLIAM H. DONNER.

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