US2147301A - Method and apparatus for rolling metal - Google Patents

Description

Feb. 14, 1939. F. KRAUSE METHOD AND APPARATUS FOR RQLLING METAL Filed Oct. 29, 1935 3 Sheets-Sheet 1 0 776 F H 1 1 l l INVENTOR. L JAM R. /W BY AM, 6W2? 62-14 WW1 MM.

" ATTORNEY! METHOD AND APPARATUS FOR ROLLING METAL Filed Oct. 29, 1955 3 Sheets-Sheet 2 46 3.9 4 1 44 33 Wgmmm 42 s 37 INVENTOR. WITNESSLIS 9 47 Y Q MM WW 44 ATTORNEYA.

Bill

Patented Feb. 14, 1939 UNITED STATES PATENT OFFICE Frank R. Krause, Ellwood City, Pa.

Application October 29, 1935, Serial No. 47,237

29 Claims.

This invention relates to a method and apparatus for rolling metal, and more particularly to the controlling of slippage of rolls against the entering portion of a metal blank at or near its lrst contact zone with the rolls to limit backard displacement of the metal and to cause to extrude through the roll passwhile being illed.

Prior to this invention it has been proposed to roll blanks of metal by pushing them through a pair of rolls disposed between substantially parallel tracks along which the rolls are rolled by their frictional engagement with the blanks. However, by pushing a blank through the rolls in this manner the metal of the blank is not prevented from flowing backwardly relative to the entering portion of the blank as it is displaced by the rolls, and the rolls will slip against the blank in its first contact zone with them. Both the roll slippage and backward flow of metal contribute to a condition in which the rolled portion of the blank emerging from the roll pass does so at a velocity only slightly greater than the surface velocity of the rolls, whereby the rolling efiects very little extrusion of the metal. The amount of reduction that can be taken with such a millis limited to the coemcient of friction between the rolls and blank, and il greater reductions are attempted the blank will not enter the bite of the rolls nor will it pass between the rolls, but will push them along with their surfaces sliding against the front end or entering section of the blank. On the other hand, if a blank of metal is pushed through a conventional rolling mill in which the rolls are journaled in stationary bearing: the draft is not limited by the coefficlent of friction because the rolls are mounted in fixed position from which they can not be moved by "the blank, but there is a serious disadvantage in that the bite angle for any given draft is greater than in the type of mill first referred to. so that stress on the mill and a blankls correspondingly increased. When rolling light sections, the'iorce required to cause the blank to pass between the rolls becomes too great, and as a result the blank upsets instead of passing between the rolls. r,

In eithercase, when a blank is being rolledthe rolls revolve at .a speed which is but slightly less r than the speed of the rolled portion of the blank away from the rolls. In other words, the rolls turn at a higher speed than'thespecdot' the portion of the blank entering the bite of the rolls,

andtherefore slip thereon. The so-called ex- 'trusioniorces to which'the blank is subjected in being rolled are only partially effective because of this slippage. It has been found that the metal can be improved if it is more completely, if not entirely, extruded" between the rolls while being rolled by limiting or substantially eliminating their slippage against the entering portion of the blank in the bite zone of the rolls.

In an ordinary rolling mill the rolls engage the blank at a sharper angle in the entering portion of the roll pass than in the remainder there- 01. Therefore, the greater resistance of the rolls to the entering oi the blank than to its exit causes a greater length of the portion of the blank in the pass to tend to flow backwardly than forwardly. As a result, the neutral point at which the surface speed of the rolls is the same as the linear speed oi the blank is always in the forward or delivery half of the pass. From that no-siip point forward the metal of the blank is extruded, but it is not extruded behind that point. Consequently, in the past extrusion in a rolling mill has been quite limited, but with my invention substantial or material ill extrusion can be efiected, substantial being used herein to mean extrusion in a mill in which the neutral or no-slip point of engagement of rolls and blank lies behind the location of the neutral point in an ordinary rolling mill in which slippage oi the rolls against a blank is not positively controlled. For best results, the no-slip point should lie Within the first or rear half of the roll-blank contact zone.

. lt is among the objects of this invention to provide a method of simultaneously rolling and extruding metal while passing between a pair of rotating rolls, in which slippage oi rolls against the entering section of a metal blank being rolled thereby is controlled and can be substantially eliminated if desired to eilect as complete extrusion of the metal as possiblewhile being rolled, and in. which greater reductions can be taken than har'sfbeenv possible heretofore.

It is' alsoa'mong the objects 'of'this invention to provide apparatusiorcarrying out the foregoing method which is relatively inexpensive, strong, easy'jtooperata'lantl adapted to take g reat'er re'ductions than heretofore. ff:

According to this invention'the' rotation of mill l irolls' i s controlled to obtain a predetermined ratiobetween theirjspeed andithe relative linear speed ores elongate blank andthe' rolls toward .each other while'iorce is applied to the blank in the direction "of itslongitudinal axis and towards therolia" Also, the reaction oi the-force just mentioned occurs at "the" periphery "of the rolls approximately opposite to the pass, and not at the roll axes.

The invention is illustrated in the accompanying drawings in which Fig. 1 is a view of the delivery end of a mill; Fig. 2 is a vertical section thereof taken on the line lIII of Fig.' 1; Fig. 3 is a view, similar to Fig. 2, of another embodiment of the invention; Fig. 4 is a vertical section taken on the line IVIV of Fig. 3; and Fig. 5 is a vertical section, somewhat diagrammatic, of another modified embodiment of the invention.

Referring to Figs. 1 and 2 of the drawings, a massive bed-frame I, having parallel side walls 2 at one end connected by an end wall or abutment 3, is mounted on a suitable foundation. Movable longitudinally of the bed-frame is an open-ended track housing 4 supported by wheels 6 journaled in the sides thereof and traveling on horizontal tracks I at the sides of the bed-frame base.

Reciprocable longitudinally within this housing is a roll housing 8 open at top and bottom and provided in the tops and bottoms of its side walls with vertical recesses 9 in which bearings H are loosely mounted for vertical movement. The necks of a pair of rolls l2 are journaled in these bearings, and when no metal is between the rolls they are biased away from each other and into frictional engagement with parallel flat track plates l3, secured to the top and bottom walls of the track housing, by coil springs l4 compressed between depressions in the inner ends of recesses 9 and bearings ll. As shown in Fig. 1, the ends of the roll necks are convex, and engage horizontal thrust bars l6 that are horizontally adjustable in recesses I! in the side walls of track housing 4 by adjusting screws [8. These bars center the rolls in the track housing and are engaged by the ends of the roll necks throughout their path of travel therein.

The front end of the roll housing is provided with a forwardly extending tubular support guide member l9 (Fig. 2) through which metal blanks 2| pass to enter the rolls, and which is also adapted to slidably and snugly receive the free end of a stationary ram 22 the opposite end of which is securely attached to abutment 3 of the bed-frame. The interior cross-sectional area of the tubular guide corresponds in size and shape to the cross-section of the blanks which the mill is adapted to roll, which is substantially the same as that of the ram.

To cause the rolls to roll over metal blanks abutting against the ram in the tubular guide, the rolls and roll housing are moved toward the stationary ram by means of chains or cables 23 which are secured at one end to abutment 3 and extend rearwardly along the ram and outwardly around sheaves 24 mounted on the roll necks outside of the roll housing. From the sheaves the cables extend back to drums or reels 26 journaled in sides 2 of the bed-frame where they are rotated by any suitable power means, as shown in Fig. 2.

It will thus be seen that the rolls float. term "float or floating", as used in the description and claims herein, refers to a roll which is mounted for rotation by a force couple in which the forces are applied only at the periphery of the roll substantially diametrically opposite to each other, as distinguished from a roll journaled in the customary manner on its axis so that the reaction to a force applied at the periphery of the roll is at the roll axis.

The mill is prepared for operation by discon- Thenecting the reels from their source of power and moving the two housings back away from the ram to the opposite end of the bed-frame. This can be done in any suitable manner such as by counterweights 21 and 28, weight 21 moving the track housing and weight 28 causing cables 23 to unwind from the reels and permit the roll housing to move backwardly too. When ready to beginoperation the roll housing is at the front or right end of the track housing as seen in Fig. 2, with the front end of tubular guide I9 spaced from the ram so as to permit the insertion of metal blanks 2| in the guide. Reels 26 are then rotated to wind up the cables which rotate the sheaves and rolls in the direction of the arrows. The frictional engagement of the rolls with tracks l3 of the track housing causes it to be moved in the same direction as the roll housing, 1. e., toward the ram, so that the track housing moves forward relative to the roll housing while both housings are moving forward together in the direction of the arrows.

As soon as the rolls reach a blank 2|, which is prevented from moving backwardly by the stationary ram, they roll onto the blank and in so doing they force the metal of the blank to pass between them and be reduced by simultaneous extrusion and rolling. As the blank can not move away from the rolls, or the rolls away from the blank, the metal of the blank can not flow backwardly as it is displaced by them, and as the rolls are positively moved by the cables toward the tail-end of the blank, the blank must necessarily pass between the rolls, whereby greater reductions can be taken than heretofore. After the blank has been reduced by the rolls the resulting slab is removed from the mill, the cable reels are released and counterweights 21 and 28 pull the two housings back to their starting positions at the rear end of the bed-plate.

Due to the frictional engagement of the rollrotating cables with sheaves 24, the rolls can not be rotated faster by the more rapidly moving reduced portion of the blank than they are being rolled forward by the cables, and therefore they are prevented from slipping on the entering portion of the blank. Consequently, the peripheral speed of the rolls at their point of engagement with the entering portion of the blank is substantially the same as the linear speed of the blank relative to the rolls, and the metal of the blank is subjected to substantially as complete extrusion, as far as longitudinal movement is concerned, as can be efiected in a rolling mill. The extrusion is more complete when the blank is of a shape, such as a tube, requiring grooved rolls, or when a blank is rolled in a roll pass. As the rolls of the mill described herein are not turned through their axes but at their peripheries, the apex of the bite angle of each roll, as well as the point of reaction of the force exerted longitudinally of the blank toward the rolls, is at its point of engagement with the track so that for any given draft the bite angle is smaller than for a like draft ona mill in which the apex of the bite angle is at the axis of a roll. The smaller the bite angle the less the stresson the cross section of the blank from a force exerted longitudinally of the blank and toward the rolls, and therefore with this mill reductions can be taken with less stress on the entering section of the blank than with those in which the rolls are turned through their axes with force acting on the entering section of a blank.

The function of "backing rolls is performed by 15 the track housing and steel track plates l3 which are considerably less expensive initially and in upkeep than such rolls, but the mill is strong and durable and easy to operate. The tubular guide member prevents long .blanks from buckling due to the longitudinal compression exerted on them by the relative movement of the ram and the rolls towards each other. If desired, some of the load on the rolls can be removed by aiding them in moving the track housing forward, such as by connecting a suitable source of power to the latter directly.

In the embodiment of the invention shown in Figs. 3 and 4 an open-ended track housing 3i is formed in and as a part of a bed-frame 32 relative to which, unlike the track housing referred to hereinbefore, it is stationary. Disposed in this housing for movement longitudinally thereof is a roll housing 33 open at top and bottom and provided in the tops and bottoms of its side walls with vertical recesses 34 in which bearings 36 are slidable vertically. Projecting through these bearings are the necks of a pair of rolls 31. The bodies of the rolls frictionally engage parallel track-plates 38 secured to the top and bottom walls of the track housing between the sides of the roll housing, and the ends of the roll bodies engage the sides of the roll housing to prevent the rolls from moving endways therein.

Extending from the front end of the roll housing is a tubular guide member 33 through which elongate metal blanks 4| are pushed into the bite of the rolls by a means, such as a movable ram 42, applying force to the blank in the direction of its longitudinal axis. In addition to being a guide for the ram and blanks, tubular member 39 is also a support for them and prevents long blanks from buckling under the compression of the ram as it moves towards the rolls.

The ram is moved through the tubular guide by 1 any suitable means, such as a hydraulic cylinder, not shown, to push the blank between the rolls by which it is reduced in thickness.

- As the metal of the blank passes between the rolls it causes them to rotate, and they therefore roll against track-plates 38 from the front to the rear of the track housing and carry the roll housing and guide 38 along with them in the same direction that the ram is traveling but at a slower speed than the latter. To prevent the rolls from sliding on the track-plates, when extra heavy drafts are attempted, and thereby moving along at the same speed as the ram instead of rolling and reducing the blank, the upper and lower walls of the track housing are provided with parallel gear racks 43 the teeth of which mesh with gears 44 rigidly mounted on the projecting ends of the roll necks arid thus assure rotation of the rolls as they are moved along by the blank.

However, in spite of this, if it were attempted to take extra heavy drafts with the mill as described this far, the blank would not enter the bite of the rolls but would push the rotating rolls along ahead of it with them sliding against its end. Also, in such a mill the peripheral speed of the rolls when metal is passing between them would be approximately the delivery speed of the blank. Therefore, to prevent the rolls from merely being pushed along-1% a blank without reducing it, to control their notation relative to the linear speed of the blank entering the roll pass and to cause the rolledportion of the blank to leave the rolls on the delivery side of the mill with a considerably greater velocity than the surface speed of the mils, a gear rack 46 is disposed between upper and lower gears 44 at each side of the roll housing. Each of these center racks is provided on its upper and lower surfaces with teeth which mesh with the gear teeth and which are also of the same pitch as the teeth of outer racks 43. These center racks extend along both sides of the ram and tubular guide and are connected to suitable actuating means, such as the means that moves the ram, for moving them between gears 44 as the blank passes between the rolls.

If the center racks are moved at the same speed as the ram and blank, the peripheral speed of the rolls can not be faster than the linear speed of the blank entering the pass because gears 44 can not turn faster than the center racks In such a case the metal is not subjected to as much extrusion as when there is no slippage 'ofthe rolls on the metal. By controlling the speed of the center racks relative to the ram, more or less extrusion of the blank can be effected while it is being rolled.

It is highly desirable that when the rolls are new their diameters be greater than those of gears 44 in order to allow for redressing of the rolls. In such a case the rolls will advance a greater distance per revolution than would the gears if they were independent of the rolls. However, as the gears are mounted on the rolls so that all must advance together, outer racks 43 preferably are not rigidly mounted on the track housing. Instead, each rack 43 is shorter than the track housing and is disposed between two plates 41 connected to the opposite ends of the housing. -The rear end ofthe rack is normally spaced from the rear plate but is connected thereto by a pin 43 slidably mounted in an opening therein and screwed intothe end of the rack.

The opposite end is connected to the front plate I by apin 49 in the same manner, but the front pin is provided with a head between which and the front plate a coilspring 51 is compressed for biasing the rack against that plate. When the gears and rolls revolve, the racks are carried slowly backward against the resistance of springs 5| so that the gears can travel the same distance per revolution as the rolls. The same result can be obtained, if racks 43 arerigidly mounted in the housing, by mdunting a friction clutch between each gear and the adjoining roll.

The rolling mill shown in Fig. 5 of the drawings'has the general appearance of a 4-high mill, but the housing 6| is provided on the entry side of the mill with a tubular guide member 62 through which metal blanks or strip 63'is forced between working rolls 54 by any suitable'means,

such as pinch rolls 66. The axes of the working rolls in the housing'are offset in front of "the axes of. backing rolls 8! in order to distribute some of the linear force exerted by the blank against the working rolls to the backing rolls. The working rolls are'preferably further backed up against the linear force of the blank by small backing rolls 68 joumaled in the housing behind them.

To control slippage between the floating working rolls and the sheet being reduced thereby, the working rolls are positively rotated at any predetermined speed, preferably by the backing rolls which in turn are rotated by any suitable means. Slipping of the backing rolls on the working rolls when extra heavy drafts are being taken is prevented by means of gears 69 mounted on the necks of the working rolls and meshing with gears ll mounted on the necks of the powerdriven backing rolls. Preferably, gears H are connected to the backing roll necks through any well-known friction clutch (not shown) in order to permit those rolls to slip relative to gears II when necessary to compensate for the difference between the pitch diameters of gears 69 and H and the diameters of the rolls to which they are connected when the latter are redressed. The blank is caused to pass between working rolls 64 by the combined action of pinch rolls 66,

which force the blank against the working rolls, and the working rolls themselves which are driven by backing rolls 61.

As the speed at which the sheet is fed into the mill is controlled by pinch rolls 86, and the rotation of working rolls 64 is controlled by the speed at which the backing rolls are rotated, the amount of slippage of the working rolls on the sheet can be controlled, whereby the degree of extrusion of the metal can also be controlled.

According to the provisions of the patent stautes, I have explained the principle and mode of operation of my invention, and have illustrated and described what I now consider to be its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. The method of rolling an elongate blank of metal, comprising applying force to the blank in the direction of its longitudinal axis and towards a floating roll while rolling the blank by the roll with its rotation positively restricted by force applied only at substantially the periphery thereof to control slippage of the roll against the entering portion of the blank in order to effect substantial extrusion thereof.

2. The method of rolling a blank of metal, comprising applying opposing forces to the blank and a pair of floating rolls to effect relative linear movement of the blank and rollstoward each other and cause the blank to enter and pass through the rolls, and positively controlling the rotation of the rolls by force applied only to sub-r stantially the peripheries thereof to obtain a predetermined ratio between the speed of rotation of the rolls and said relative movement to control slippage of the rolls against the blank in order to effect substantial extrusion thereof.

3. The method of rolling an elongate blank of metal, comprising applying force to the blank in the direction of its longitudinal axis and towards a pair of floating rolls while rolling the blank between the rolls with the rolls turning at a surface speed equal to the relative linear movement of the blank and rolls to prevent slippage of the rolls against the blank at the bite of the rolls.

4. The method of rolling an elongate blank of metahcomprising applying force to the blank in the directionof its longitudinal axis and towards a pair of floating'rolls to cause theblank to enter and pass through the rolls, and positively controlling the rotation of the rolls by force applied only at their peripheries to obtain a predetermined ratio between the speed of rotation of the rolls and the speed of the blank relative to the rolls to control slippage of the rolls against the blank in order to effect substantial extrusion thereof.

5. The method of rolling an elongate blank of metal, comprising applying force to the blank in the direction of its longitudinal axis and towards a pair of rolls to cause the blank to enter and pass through the rolls and roll the rolls in the direction of movement of the blank, and positively controlling the rotation of the rolls to obtain a predetermined ratio between the surface speed of the rolls and the speed of the blank to control slippage of the rolls, against the blank in the entering half of the roll pass.

6. The method of working metal by rolling it between a pair of rolls supported only at their peripheries, comprising backing up the tail-end of a metal blank, effecting relative linear movement of the rolls and said backing-up means towards each other to cause the blank to be rolled between the rolls, and positively controlling the rotation of the rolls by force applied only at their peripheries to obtain a predetermined ratio between the speed of rotation of the rolls and said linear movement to control slippage of the rolls against the blank in order to effect substantial extrusion thereof.

. "7. The method of working metal by rolling it between a pair of rolls, comprising backing up the tail-end of a stationary metal blank, rolling the rolls over the blank in the direction of its tail-end, and restricting the rotation of the rolls to a speed substantially equal to their linear movement to control slippage of the rolls against the blank in order to effect substantial extrusion thereof.

8. A rolling mill comprising a roll supported only at its periphery, means for applying force to an elongate blank of metal in the direction of its longitudinal axis and towards said roll while rolling the blank by the roll, and means. for turning the roll by force applied only at its periphery at a speed limiting slippage of the roll againstf the blank in order to effect substantial extrusion thereof.

9. A rolling mill comprising a pair of rolls sup: ported only at their peripheries, means for applying force to an elongate blank of metal in the supported only at their peripheries, means for applying force to an elongate blank of metal in the direction of its longitudinal axis and towards said rolls to cause the blank to enter and pass through the rolls, and means for retarding the rotation of the rolls to obtain a predetermined ratio between the speed of rotation of the rolls and the speed of the blank relative to the rolls to decrease slippage of the rolls against the entering portion of the blank in order to effect substantial extrusion thereof.

l1. A roliingniill comprising a pair of rolls,

means for applying force to an elongate blank of metal in the direction of its longitudinal axis and towards said rolls while rolling the blank between the rolls, and means independent of said blank for turning the rolls at a speed limiting slippage of the rolls against the blank in order to eilect substantial extrusion thereof, said means acting on the rolls through force applied at their peripheries.

12. A rolling mill comprising a pair of rolls, means for backing up the tail-end of a metal blank, means for effecting relative linear movement of said rolls and backing-up means towards each other to cause the blank to be rolled between the rolls, and means for controlling the rotation of the rolls to obtain a predetermined ratio between the speed of rotation of the rolls and said linear movement to control slippage of the rolls against the blank in entering half of the roll pass in order to effect substantial extrusion thereof, said rotation-controlling means applying force to said rolls substantially at their periphery.

13. A rolling mill comprising a pair of rolls,

means for backing up the tail-end of a metal blank and for pushing the blank through the rolls to cause it to be rolled, and means for controlling the rotation of the rolls to obtain a predetermined ratio between the speed of the rolls and said linear movement to control slippage of the rolls against the entering portion of the blank in the entering half of the roll pass.

14. A rolling mill comprising a pair of rolls, means for backing up the tail-end of a metal blank, means for rolling the rolls over the blank in the direction of its tail-end, and means for positively controlling the rotation of the rolls to obtain a predetermined ratio between the speed of rotation of the rolls and their linear movement to control slippage of the rolls against the blank in order to efiect substantial extrusion thereof.

15. A rolling mill comprising working rolls,

- backing rolls therefor, means engaging the unrolled portion of a blank of metal for forcing it through the working rolls to cause it to be rolled and extruded thereby, and means for controlling the rotation of the working rolls toobtain a predetermined ratio between the surface speed of the working rolls and the linear movement of the entering blank to control slippage of said rolls against the blank to obtain substantial extrusion thereof,

16. A rolling mill comprising floating working rolls, backing rolls therefor, means for pushing a blank of metal through the working rolls to cause it to be rolled and extruded thereby, and means for rotating the working rolls, said means being adapted to control the rotation of the working rolls to obtain a predetermined ratio between the surface speed of the working rolls and the linear movement of the entering blank to control slippage of said rolls against the blank in the entering half of the roll pass.

1'7. A rolling mill comprising working rolls, backing rolls therefor, pinch rolls for forcing a blank of metal through the working rolls to cause it to be rolled thereby, means for driving the pinch rolls, means for gearing the working rolls to the backing rolls, and means for driving the backing rolls at a speed having a predetermined ratio to the speed of the blank whereby to control slippage oi the working rolls against the blank.

18. A rolling mill comprising an abutment for backing up the tail-end of a blank of metal, a

housing reciprocable relative to said abutment, a pair of rolls journaled in said housing, sheaves rigidly mounted on said rolls, cables anchored to said abutment and passing around said sheaves, and means mounted at the abutment end of the mill for reeling in the free ends of said cables to cause the rolls to roll over said blank.

19. A rolling mill comprising an abutment for backing up the tail-end of a blank of metal, a track housing reciprocable relative to said abutment, a roll housing disposed in said track houring, a pair of rolls journaled in said roll housing and frictionally engaging the track housing, means connected to the roll housing for supporting said blank, sheaves rigidly mounted on said rolls, cables anchored to said abutment and passing around said sheaves, and means mounted at the abutment end ofthe mill for reeling in the free ends of said cables to cause the rolls to roll over said blank.

20. A rolling mill comprising a rack housing, racks mounted inside of the housing on two oppo site walls thereof, a roll housing loosely disposed in the rack housing, a pair of rolls journaled in the roll housing, gears mounted on said rolls and meshing with said racks, means connected to the roll housing for guiding a blank of metal to the rolls, means for pushing said blank through the rolls, and a rack meshing with said gearing between the rolls and adapted to be moved forward with said blank at a speed having a predetermined ratio to the speed of the blank whereby to control slippage of the rolls against the blank.

21. A rolling mill comprising a rack housing, racks mounted inside of the housing on two opposite walls thereof, a roll housing loosely disposed in the rack housing, a pair of rolls journaled in the roll housing, gears mounted on said rolls and meshing with said racks, means connected to the roll housing for guiding a blank of metal to the rolls, means for pushing said blank through the rolls, and a rack connected to said pushing means and meshing with gears on both rolls simultaneously for controlling slippage of the rolls against the blank.

22. The method of reducing an elongate metal blank, comprising supporting a pair of rolls only at their peripheries, effecting relative linear movement of said blank and rolls toward each other to cause the blank to be rolled, and positively controlling rotation of the rolls relative to said linear movement to control slippage of the rolls against the blank to thereby effect material extrusion of the blank.

23. The method of reducing an elongate metal blank between a pair of floating rolls, comprising applying opposing forces to the blank and rolls to effect relative linear movement of the blank and rolls toward each other to cause the blank to pass between the rolls and to positively control the speed of their rotation relative to the speed of said relative linear movement, said forces acting on said rolls only at substantially the periphery thereof.

24. The method of rolling an elongate blank of metal, comprising applying force to the blank in the direction of its longitudinal axis and towards a pair of rolls while rolling the blank between the rolls with their rotation restricted to control slippage of the rolls against the blank, the rolls being turned by force applied at their peripheries, said turning force being in addition to that furnished by the blank itself.

25. The method of working metal by rolling it between a pair of rolls, comprising backing up the tail-end of a stationary metal blank, applying a force at substantially the periphery of said rolls to roll them over the blank toward its backed-up end, and restricting the rotation of the rolls to a speed substantially equal to the linear speed of the working surface of the rolls.

26. A rolling mill comprising a pair of floating rolls, means for backing up said rolls, means for backing up the tail-end of a metal blank, and means for applying opposing forces to the rolls and blank backing-up means to eiiect their relative linear movement toward each other to roll the blank between the rolls and to positively control the speed of rotation of the rolls relative to the speed of said relative linear movement, whereby extrusion of the blank being rolled is positively controlled, said forces acting on said rolls only at substantially the periphery thereof.

27. A rolling mill comprising a pair of floating rolls, means for backing up said rolls, means for applying force to an elongate blank 01 metal iongitudinally thereof and towards said rolls while rolling the blank between them, and means independent of said blank and roll backing-up means for turning the rolls at a predetermined speed, said turning force being applied to the rolls at substantially the peripheries thereof.

28. A rolling mill comprising a pair of rolls, means for backing up one end 01' a metal blank, and means for applying a force at substantially the periphery of said rolls to roll them over the blank toward said backed up end, said force-applying means controllingthe rotation of the rolls relative to their movement longitudinally of the blank to thereby control the amount of extrusion 01' the pass-entering portion of the blank being rolled.

29. A rolling mill comprising a pair of rolls, means for backing up the rolls, means for backing up one end of a metal blank, and means for applying a force at substantially the periphery of said rolls to roll them over the blank toward said backed-up end, said force-applying means controlling the rotation of the rolls relative to their movement longitudinally of the blank to thereby control the amount of extrusion of the blank being rolled.

FRANK R. KRAUSE.

CERTIFICATE OF CORRECTION. Patent No. 2,lh7,50l. February 1h, 1959.

' FRANK R. KRAUSE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, first column, line 19, claim 12, after the word "in" insert the; 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 25th day of April, A.D 1959c Henry Van Arsdale (Seal) Acting Commissioner of Patents.

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