US2105736A

US2105736A - Process and mechanism for rolling endless lengths of metal in reversible mills

Info

Publication number: US2105736A
Application number: US741133A
Authority: US
Inventors: Edwin B Hudson
Original assignee: AMERICAN RELLING MILL Co
Current assignee: AMERICAN RELLING MILL Co
Priority date: 1934-08-23
Filing date: 1934-08-23
Publication date: 1938-01-18
Anticipated expiration: 1955-01-18

Description

Jan. 18, 1938. E. B. HUDSON ECHANISM FOR ROLLING ENDLESS PROCESS AND M LENGTHS 0F METAL IN REVERSIBLE MILLS Filed Aug. 25, 1954 2 Sheets-Sheet l INVENTOR. fam/vfi/vuasoM ATTORNEYS.

Jan. 18, 1938. E. B. HUDSON 2,105,736

PROCESS AND MECHANISM FOR ROLLING ENDLESS LENGTHS OF METAL IN REVERSIBLE MILLS Filed Aug. 25, 1934 2 Sheets-Sheet 2 INVENTOR [aw/N5 fluasam ATTORN E Y5.

Patented Jan. 1

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' PROCESS AND MECHANISM FOR ROLLING ENDLESS LENGTHS F METAL IN RE- VERSliBlL-E Ii/HILLS Application August 23,

16 Claims.

My invention relates to the rolling of metal in reversible mills, the metal being carried down to gauge by a plurality of forward and backward passes. Hereinafter I shall describe my invention 5 in an exemplary embodiment which has to do with the rolling of strip metal of sheet width in a single four-high reversible mill. It will be understood that neither the character of the metal being rolled nor the nature of the mill itself, are necessary limitations upon my invention; and where I have referred to a single mill, it will be understood that more than one mill may be employed, if desired. Of course, if a tandem train of mills is employed, consisting of enough mills so that the metal may be reduced to the desired finished gauge by a single passage through the train, then there is no need of forward and backward rolling. Under some circumstances, however, the capital investment, floor space or the like, required to set up a tandem train of mills as referred to, may not be available; or for some other reason, it may be desired to use a fewer number of mills and obtain the desired reduction in gauge by passing the strip a plurality of times through each mill. In its ultimate simplicity, of course, such a system would consist of but a single mill; in more elaborate embodiments more mills may be employed, and the desired reduction effected by fewer form ward and backward passes, as will be readily understood.

My invention further has to do with the use oftension in rolling, by which I imply suflicient tension in the piece to assist materially in the reduction thereof, as distinguished from the relatively minor tensions which might be employed merely for the purpose of assisting in the feeding of the mill or mills, or in reducing camber.

It has hitherto been suggested to roll-strip material under tension in a single mill. The way in which this is done is by providing, at either side of the mill, a tight or tension coiler, threading a piece through the mill, attaching it to both coilers, and then proceeding to roll the piece forwardly and backwardly through the mill, the forward coiler on each passage of the metal being driven, and the rear one braked or otherwise retarded. The tension in the piece may be the same on either side of the mill, or of different values, as desired, and this is characteristic also of my invention. A primary difficulty with procedures of this character hitherto has arisen from the fact that it is not possible, under conditions of tension, to roll a single piece entirely through the 55 mill at each pass. So long as forward and back 1934, Serial-No. 741,133

ward rolling is being done, there always must be an end of the piece extending from the mill to the coiler, as a consequence of which this end is not reduced; and while great reductions may be accomplished in the tension mill, yet the wastage is high because of the unreduced ends of the strip. There is no very good way of cutting down this wastage, because, with tight coilers or like apparatus the amount of strip which may be handled is limited. I

It therefore appears, as a primary object of my invention, that I provide a method and means for rolling in a backward and forward process strip metal under tension without wastage. I accomplish this essentially by the provision first, of a continuous supply, and second, of means for acting upon a given length of the continuous supply until all portions thereof are reduced to the desired gauge, and third, by providing for the removal of the portion of the metal so reduced, and the reducing of a contiguous portion thereof without leaving any unreduced portions in the length of the strip. Inthis way wastage is reduced'to an inconsiderable minimum.

In previous methods of reducing strip metal under tension by forward and reverse rolling, a breakage in the strip has caused serious inconvenience, and has greatly multiplied the necessary wastage, In some cases both sections of the broken strip have had to be treated as scrap.

In other instances, one section may still be rolled, but the amount of scrap is, of course, greatly increased. Another object of my invention, therefore, is the provision of means and a method for reducing'wastage arising from breakage of the strip.

Still another object of myinvention is the provision of better control means and method in a mill of this type, as will be set forth hereinafter.

These and other objects of my invention which will be apparent to one skilled in the art upon reading these specifications, I accomplish by that series of process steps and in that mechanism of which I shall hereinafter set forth two exemplary embodiments, reference being had to the accompanying drawings, wherein Figure 1 is an elevational view, semi-diagrammatic in character, of an exemplary mill and associated apparatus.

Figure 2 is a plan view thereof.

Figure 3 is an exemplary view of a somewhat different assembly of apparatus.

Figure 4 is a plan view thereof.

, In the practice of my invention I provide a mill of a reversible type adapted for forward and reverse rolling. I also provide means for sup= plying the mill with a continuous band of metal. I lead this metal through the mill, and essentially I segregate a portion thereof for rolling, which portion is then passed forwardly and bacirwardly through the mill as many times as may be necessary to give the desired reduction. This segregation of the metal may be accomplished in several ways, two of which I shall describe in detail. The first of these comprises clamping the metal on either side of the mill, allowing sufilcient length between the clamping means for the rolling desired. Between the clamping means and the mill, on both sides, there will be located take-up means to handle first the length of the metal provided for rolling, and second, the length of the metal as increased by the rolling operation. These take-up means will, in this instance, be means which also can supply to the piece being rolled, irrespective of its length on either side of the mill, the desired amounts of tension. Another provision which may be made, is to place on either side of the mill :3. continuous pulling device, and beyond these pulling devices to provide means for taking up the strip, but not under tension. Preferably there will be located between the pulling devices and the mill, a means for applying to the strip a constant, predetermined, continuous tension, irrespective of its length. Under either procedure it is necessary, of course, to provide means for taking up and paying out the strip as it is being rolled. The ordinary loopers are not flexible and responsive enough to make their use particularly desirable. Consequently, a part of my invention resides in the provision of a new type of take-up device for the purpose described.

In Figures 1 and 2 I have indicated at i a stand of four-high rolls which may be driven,

as will be readily understood, through suitable gearing from a reversible motor 2. I have indicated at t a decoiling device in which coils of strip metal are unwound and flattened out so that the leading edge of .one such strip may be welded to the trailing edge of another such strip at a welding device This welding device may be of any style found suitable, although I prefer to employ an electric butt welder. A device 5 operates to remove from the weld any excess metal on either side thereof, so that the resultant strip may be rolled; and this mechanism will hereinafter he referred to as a flash cutter. Pinch rolls 6 follow the flash cutter, and at a station marked 8, provision is made for taking up a short length of the strip indicated at 8, as may be required by the exigencies of welding. The strip next passes under a hydraulic clamp 9, which is one of the segregating means aforesaid. In my take-up device I have provided a carriage it mounted slidably on tracks M. This carriage bears a series of rolls l2, and another series of rolls i3 is mounted on. a fixed end support it. The strip 8 is passed back and forth between the rollers i2 and I3 in zigzag formation, as shown, so as to take up a considerable length thereofl The carriage is propelled to the right by the pull of the strip. It is propelled to the left by cables i5 operating on a driven drum it. as shown. This drum is moved through a suitable train of gearing by a motor H. The carriage in the mechanism just described is shown nearthe right hand end of its path of travel. In other words, it is shown as hating paid out very nearly as much strip as it can.

It will be clear that the driving or bramng escapee effect of the motor iii upon the carriage it will exert tension upon the strip 8. It is desirable'to provide means for maintaining this tension constant in spite of the sporadic variations which might occur either in the mechanism, the rolling, or the characteristics of the material being rolled. To this end I may make the hydraulic clamp ii slidable bodily in ways 38 in the frame member 9a, and urge it in a direction away from the carriage it (Figure 1) by connecting it to the piston of a cable 12 to a rheostat Q3 controlling the speed'of the motor ii, so that the force exerted by the motor on the strip may be compensated for such changes as occur.

Other ways of actuating the carriage may, of course, be employed. One of these ways would be to actuate the carriage by cables operated by weights which would exert thereon a constant force, irrespective of the position of the carriage. Another way would be to actuate the carriage either directly or indirectly, by means of a fluid cylinder under constant pressure. The carriage may have an index finger or pointer iii, reading along a fixed scale it, which will show the length of strip taken up in this mechanism at any given time, as determined by the position of the carriage.

The strip 8 thence passes through the mill and to a second take-up device comprising a carriage it, end take-up rolls 2i and motor 28. This carriage has been shown in its extreme right hand position, i. e., having taken up as much strip as possible. A final hydraulic c1amp'22 is provided.

Preferably this clamp likewise is movable under the actuation of a cylinder 68, fed by an accumulator 415 controlling a rheostat as hereinabove described for the clamp d.

Beyond this, pinch rolls 23 serve to feed the strip to a shear 2 3, after which individual coils are formed from the rolled section in a coiler indicated at 25. The hydraulic clamps 22 and 9 may be actuated through suitable conduits indicated generally at 26, by a hydraulic pump 27, connected to the accumulators ti and 35.

In operation, assuming that one length of metal has already been rolled, and has passed beyond the clamp 22 so as to be sheared and coiled as at M and 25, the take-up device on the right hand end of the machine in Figures 1 and 2 will be in such a position that it holds the least possible amount of metal. The clamp 22 will be closed. The clamp 9 will next be opened, and strip allowed to be fed to the left-hand take-up device until that device has taken up as much strip as may be desired. course, to fill up the left-hand take-up device, because some provision must be made for the expected elongation; Next the clamp s is closed, and the mill started rolling in the forward direction. The strip at either end of the machine beyond the clamps 9 and 22 is of course, stationary; but intermediate these clamps the strip will be rolled by being paid out of the left hand take-up device and taken up by the right hand take-up device. Both take-up devices are pro- It will not be advisable, of

aiceyse vlded with tensioning means as described, so that the tension on the strip forwardly and rearwardly of the mill will be maintained to constant values, irrespective of the amount of strip taken 1 indicated at on the entering side of the mill,

til

up in either of said devices.

When the left-hand take-up device has paid out as much strip as'lt can, the mill is reversed, whereupon the right-hand take-up device starts paying out strip, which is taken up by the lefthand take-up device. By a reversal of these procedures the strip is thus rolled forwardly and backwardly until the desired reduction has been accomplished. When this is done, the left-hand take up device is moved so as to pay out the strip, and the right-hand take-up device is likewise moved to pay out the strip. The clamp 22 is released, and. the pinch rolls 23 feed out the already rolled strip. While it is not necessary to do this, it is usually preferable to stop the strip in such a position that the unreduced portion thereof lies aft or slightly ahead of the mill 5. When the right-hand take-up device has paid out as much strip as it can, the clamp 22 is again tightened up, the clamp 9 released, and additional strip is fed into the system as previously described. lfhus, by a continuation of these steps an endless length of strip may be rolled so that all parts thereof are reduced to final gauge without any wastage whatever arising from unreduced portions in the length of the strip.

In Figures 3 and 4 I have illustrated a different type or apparatus in which the mill is again in-. dicated at l and the decoiler, welder, flash cutter. the pinch rolls, the shear, and the final coiler, are the same, and are indicated by the same numerals. In this system, however, I have a continuous pulling device. This may be of a type set forth in my copending application, Serial No. 668,100 filed April 26, 1933. A second continuous puller is indicated at lid, on the leaving side of the mill, and may be of the same type. Intermediate the mill and these pulling devices I have indicated at M and 3? continuous tension take-updevices. These devices are fully described in my said copending application.

They have been indicated here only diagrammatically but they comprise in essence a pair of interspaced knee rolls 33 and a vertically movable roll 3%. The vertically movable roll is moved either upwardly or downwardly under a constant force. This may be done by connecting these rolls to a hydraulic cylinder driven by a suitable pump in connection with an accumulator, or the rolls may be connected withcables to which weights are attached, orthe like. The strip is passed about the knee rolls and over or under the movable rolLs, so that a length thereof will be taken up between these rolls as shown. Since the movableroll has applied to it a constant force, the strip between the pullers and the mill will have in it a constant, continuously applied tension, irrespective of its length. Since the length of the strip in these tension take-up devices has ultimate r limits, it is preferable to cause the length of the strip itself to control the speeds of the dynamic instrumentalities in the train, such as the mill and pullers. This may be accomplished as set forth in my copending application referred to, by connecting a rheostat actuating the puller or mill motors to the movable roll 35, so that when the length of the strip has increased or decreased beyond predetermined minimum amounts, the

dynamic instrumentalities will be slowed down or speeded up, as may be required.

In this system I have shown lying beyond the pullers on either side of the mill, take-up devices indicated generally at 35 and 36. These devices will preferably be of the type described in connection with Figures 1 and 2, but are not necessarily so, since the problem here is merely to take up the strip under only such tension as may be required for this specific purpose. The tension of the strip for rolling purposes is accomplished essentially solely between the pullers and the mill. As a consequence, no great force need be exerted upon the carriages in the take-up de--

vices

35 and 36. In this system it may be preferred to drive the carriages of these take-up devices along the tracks merely by motors connected with the wheels or trucks thereof, so that there will be no tendency beyond the pullers to break the strip on either side of the mill. Clamps may likewise be provided, if desired, andI have indicated such clamps at 37 and 3%.

In this system the rolling tension is developed between the pullers and the mills, and is maintained constant on either side of the active pass by the static tension take-up devices referred to. These will be operative for the purpose, irrespective of variations in the rolling conditions, but may be shifted to new values when desired, as will be readily understood. The strip is rolled forwardly and backwardly as before, the operation of the take-up devices being the same, excepting that they are relied upon neither to produce nor to maintain the tension.

It will be understood that modifications may be made in my invention without departing from the spirit thereof.

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

1. In combination, a rolling device, means for providing an endless supply of metal thereto, means for segregating a portion of said supply on either side of said 'rolling mechanism, and means for taking up and paying out said segregated portion on either side of said rolling mechanism.

2. In combination, a rolling mechanism, means for providing an endless supply of strip metal thereto, segregating means on either side of said rolling mechanism, and means intermediate said segregating device and said rolling mechanism for taking up and paying out said strip.

3. In combination, a rolling mechanism, means for providing an endless supply of strip metal thereto, segregating means on either side of said rolling mechanism, means intermediate said segregatlng device and said rolling mechanism for 4 taking up and paying "but said strip, and means for exerting a force on said taking up and paying out means whereby to tension the strip.

4:. In combination in the order named, welding means for forming a continuous supply of metal, clamping means for rearwardly segregating a portion of said supply, taking up and paying out means, a rolling mechanism, a second taking up and paying out means, and clamping means acting forwardly of said mill to complete the segregation of a portion of said continuous supply for reversible rolling.

5. In combination in the order named, welding means for forming a continuous supply of metal,

clamping means forrearwardly segregating a second continuous pulling device, and a second reversible taking up and paying out means.

7. The combination claimed in claim 6, with means intermediate said pulling devices and said rolling mechanism for controlling the tension in said strip to predetermined constant amounts for each pass.

8. In combination, clamping means, taking up and paying out means, a rolling mechanism, a second taking up and paying out means, and a second clamping means, said clamping means be-- able and means for exerting a constant force thereon to control said movement, means for applying a tension-producing force to said taking-up and paying out means, and an operative connection between each clamping means and its adjaoent taking up and paying out means to vary the force applied to the latter in accordance with movements of the former.

iii. A process for the reversible rolling of strip metal without end wastage which comprises providing an endless supply or metal, segregating for rolling purposes a portion or said endless supply, rolling said segregated portion forwardly and backwardly under tension until reduced to the desired gauge, and afterward segregating without severing a contiguous portion of said supply, rolling said last mentioned segregated portion, and continuing the steps of the process aforesaid, whereby to produce an endless, uniform rolled supply of metal, from which parts may be severed for use after the completion of the rolling thereof.

11. A process for the reversible rolling of strip metal without end wastage which comprises providing an endless supplyoi said metal, segregating a portion thereof between fixed members while maintaining the continuity of said supply, and

aromas tioned portion, and continuing the steps of said process on said endless supply, whereby to produce an endless supply of uniform rolled product, from which after the completion of the rolling, portions may be cut for use.

12. The process of claim 11 which includes the taking up and paying out of parts of said segregated portions during said rolling and between the rolling mechanism and said fixed members.

13. The process as set forth in claim 11 including the step of exerting a substantially constant tension during the reversible rolling on at least that part of said segregated portion being rolled which lies ahead of the rolling mechanism in the direction of rolling. Y

14. A. process for the reversible rolling of strip metal without end wastage, which comprises providing an endless supply of strip metal, segregating without severing a portion of said endless supply between fixed members, intermediate said members passing said segregated portion forwardly and backwardly through a reversible rolling mechanism, and continuously pulling on said portion in a direction at least forwardly of the mechanismwhile taking up and paying out said segregated portion forwardly and rearwardly of the point of application of said pull.

15. The process set forth in claim 14 involving the steps of maintaining between the point of application of said pull and said rolling mechanism constant, predetermined and continuous tension on said strip metal.

16. in combination, means for providinga continuous supply of strip metal, reversible taking up and paying out means, a continuous pulling device, a rolling mechanism, a second continuous pulling device, and a second reversible taking up and paying out means, means intermediate said pulling devices and said rolling mechanism for controiling the tension in said strip metal to predetermined constant values for each pass, and means whereby said last mentioned means are operative to govern the speeds of other dynamic instrumentalities.

EDWIN B. HUDSON.