US2353290A - Apparatus for rolling strip metal - Google Patents

Description

R. G. BENNEWITZ APPARATUS FOR ROLLING STRIP METAL July 1l, 1944.

Filed Dec. 2, 1940 2 Sheets-Sheet 1 ATTORNEY5 July 1l, 1944. R. G. BENNEwl-rz APPARATUS FOR ROLLING STRIP METAL 2 sheets-smet 2 Filed Dec. 2, 1940 a: ...q Y O/ mw* W: w. MM NT. N :Gf 1MM K Q m u p0: R @www u N %M\ wm ma m .@w Kw Nm u@ ww W /m/: ha L@ www wm 1 :2:55:53 .u R f 55m@ ATTORNEYS methods and apparatus for cold Patented July 1 1, 1944 2,353,290 APPARATUS FOR ROLLING STRIP METAL Richard G. Bennewitz, Jersey City,

Steel Company of to Crucible N. J., assignor America, New

York, N. Y., a corporation of New Jersey Application December 2, 1940, Serial No. 368,125

4 Claims.

This 'invention relates to improvements in drawing and rolling metal rod, wire, narrow strip or like stock having a thickness comparable to its width, and is particularly adapted for the cold drawing and rolling of such stock to form special shapes.

This application is a continuation in part of applicants copending parent application, Serial No. 350,789, filed August 3, 1940. Whereas said parent application pertains more particularly to method and apparatus for the cold reduction by rolling of metal strip which is relatively wide in relation to its thickness, the present invention is concerned primarily with the cold reduction by combined drawing and rolling, of metal rod, wire, narrow strip, or like stock, having a thickness comparable to its width, as well as for imparting special shapes thereto, such as a square, hexagonal, etc., contour.

As brought out in said parent application, apparatus for cold rolling metal strip has heretofore been devised, in which the strip is pulled between a pair of relatively small reducing or working rolls, each backed by an anti-frictionally supported backing roll of much larger diameter, the axes of the four rolls all being in a common plane which is perpendicular to the direction of movement of the strip, this constituting the so-called 4-high construction. This construction, however. is subject to a number of disadvantageous and undesirable features as follows. Owing to the fact that the working rolls are backed'only in a direction perpendicular to the direction of rolling, but are unbacked or unsupported in the direction of rolling, they are subject to lateral flexure or bending in this direction due to the pull exerted by the strip, such as is productive of a strip of non-uniform transverse thickness, and produces riilling at the edges. To minimize this tendency the working rolls must be made relatively large and the diameter of the backing rolls correspondingly increased to maintain their appropriate dimensions in relation to the working rolls. These large working rolls diminish the maximum reduction or bite that can be employed during rolling, while the combination of large Working and backing rolls greatly increases the overall dimensions, weight and cost of the mill. Moreover, with the 4-high construction, although the backing rolls maybe provided with anti-friction bearings, such as roller bearings, this cannot be done with the Working rolls due, for onev reason, to lack of space and also, for the more important reason, that the working rolls must be set up tightly in split friction bearings, of babbitt or the like, to hold the working rolls rigidly in line as required with the backing rolls, and in order to make the requisite adjustments from time to time during rolling, rto maintain the working rolls so aligned with the backing rolls. Anti-friction bearings, such as roll or ball bearings, could not be employed for the working .rolls in the 4-high construction, inasmuch as the play in the bearings thus introduced would cause misalignment of 'the working and backing rolls and thus produce riillng, buckling and non-uniform thickness of the strip. The fact that the working rolls must be thus tightly set up in split friction bearings in the 4-high construction entails the further disadvantage that a steady flow of lubrication is required on the roll necks in order to prevent over-heating of the bearings and roll necks. Owingto this heated oil splashing on the strip, it is impossible to produce a strip having a bright lustrous finish.

It is also known to construct cold rolling mills with a pair of working rolls each of which is backed by a pair of spaced backing rolls having their axes in a plane parallel to the strip and each bearing against the associated working roll, the so-called cluster construction. In mills of this type which have been heretofore devised, however, theworking rolls have been directly driven through drive shafts connected thereto. through wobblers on the like. Owing to the drive thus applied directly to the workf ing rolls, these rolls must be made relatively heavy to minimize the resulting tendency for lateral deflection thereof, and the backing rolls must be made correspondingly larger and heavier than would otherwise be required in order to preserve the proper relative sizes of the Working and backing rolls. Also the workingrolls must be made sufficiently large so that such driving connections can be made thereto. To further minimize [this lateral deflection and displacement of the working rolls, they must again be tightly set up in split friction bearings, requiring heavy and continuous lubrication during operation to prevent over-heating, with the resulting disadvantages above noted for the 4-high construction. Likewise, with this type ofV mill, it is difficult to roll strip of uniform cross-sectional thickness with a high degree of Arapidity and with no rifing or buckling of the strip, and for the same reasons explained in connection with the 4-high construction.

' in, such as In accordance with applicants invention, the cluster arrangement of the working and backing rolls is employed, i. e., each of a pair of working rolls is backed by a pair of spaced backing rolls bearing against the same, but with this important distinction over the previous types of cluster mill construction that the Working rolls are not themselves driven, but are merely cradled between and backed by their associated backing rolls. The stock being rolled, is propelled entirely by tension applied thereto, i. e., the material being rolled is pulled through the mill. Owing to the fact that eachworking roll is cradled between and backed by a pair of backing rolls, and thus automatically maintained in proper alignment there, and owing to the further fact that no drive is applied to the working rolls, no bearings, other than loose thrust bearings, are required for the working rolls. The working rolls are thus supported exclusively by the backing rolls in rolling contact therewith. Accordingly, the working rolls are subject to no overheating or frictional drag, such as is produced in prior constructions due to the friction bearings required. Also since, as stated, each working roll is cradled and automatically aligned between a pair of backing rolls in contrast to the vertical roll arrangement of the 4-high construction, and since the working rolls are not themselves directly driven, as in the case of the prior cluster mill constructions, the working rolls of applicants construction are not subject to fiexure in the direction of rolling, as is the case with prior constructions. The working rolls and their associated backing rolls may accordingly be made much smaller than in the prior types of 4c-high or cluster mills, thereby greatly reducing the overall dimensions, Weight and cost of the mill for any given size of stock to'vbe rolled. The smaller working rolls which can thus be employed permit of reducing the stock to the desired dimensions in fewer passes than previously, due to the increased bite that can be employed effectively. Rolling costs are thus reduced and a superior product obtained.

Further in accordance with applicants construction, the backing rolls are mounted in antifriction bearings, such as roller bearings. Owing to this fact and the fact that no bearings are required for the working rolls, the bearing losses for the entire mill are reduced to such a point that the strip or bar may be rolled exclusively by tension applied thereto, i. e., by pulling the strip through the mili and without danger ci rupturing the stock. The friction losses are in fact so small that the stock can be rapidly reduced at a relatively high rate of speed, for example as high as i509 feet per minute. Certain modications of applicants above mentioned improvements, in forms adapted for cold rolling relatively wide metal strip, are disclosed, as stated, in his copending application Serial No. 350,789, filed August'S, 1940, of which this application is a 4continuation in part. The present application is more particularly directed to forms of the invention which are adapted for example, to be employed for drawing and rolling special shapes, such as the conversion of round bars into square, hexagon, etc., shaped rods or wires, or the reduction in cross-sectional area or" round, square, hexagon, etc., shaped rods, wires, etc., while maintaining their contour unchanged. This may be accomplished in accordance with one aspect of the present invention by the use of work rolls having appropriately shaped grooves there- V notches, etc., or more preferably by the use of built-up work rollsl consisting oi hardened and ground washers of appropriate contour.

Cylindrical areas for contacting with the backing rolls may be provided on the work rolls closely adjacent each side of the grooved areas, thus maintaining the full beneilt of the self-aligning feature and preventing bending of the work rolls despite th'e fact that the built-up character of the roll with its grooved area tends to substantially weaken it. If it were attempted to hold in alignment such a small built-up" grooved work roll by the use of roll necks and friction bearings, as in the 4-high" type of mill, the middle portion of the roll would be free to bend in varying amounts depending on the stock tension and the shape and size of the grooves, thus making it impossible to roll the stock accurately' to the desired shape. Also if it were attempted to use the old cluster type of mill with driven workrolls of such a small built-up grooved type, it will be apparent that the above indicated difllculties with that type of mill would be greatly increased and the work roll construction would be too Weak to permit accurate rapid rolling of the stock to the desired special shapes.

'I'he present application is also particularly directed to forms of the invention which are adapted to not only roll the upper and lower surfaces of the stock, but also to roll concurrently its sides or edges to the particular shapes desired. That is, the rolling head for rolling the upper and lower surfaces, may be followed or preceded by another rolling head mounted in a position for example, at rightI angles to the first, and also having a pair of generally similar work rolls formed with grooves of desired cross sections, so that the two pairs of work rolls will serve to reduce complementary portions of the outline of the desired special shape, while the stock is advanced solely by pulling it through the two rolling heads in succession. Thus it is possible to produce round,

square, beveled or other shapes with a cold rolled finish, both on the upper the stock as well as on and lower surfaces of its edges or side surfaces. Such rolling operations could not be carried out on the known types of 4-high and cluster mills. Also the improved types of rolling heads embodying the invention are particularly adapted for use as a draw block through which the stock is pulled.

Various further and more specific objects, features and advantages o the invention will appear from the detailed description given below, taken in connection with the accompanying drawings forming a part of this specification and illustrating merely by way of example certain embodiments of the invention. 'I'he invention consists in such novel features, methods, arrangements and combinations of parts as are shown and described herein.

In the drawings:

Figs. l and 2 are plan and side views, somewhat schematically illustrating the manner in which two of the rolling heads, in accordance lwith the invention may be mounted at right angles to each other and in association with a winding drum for pulling the stock from an unwinding reel through the heads;

Figs. 3 and 4, are top and end views respectively of one of the rolling heads embodying the invention; l

Figs. 5 and 6 lare vertical sectional views taken substantially along the lines 5 5 and 6 6 of Fig. 3; and

Fig. 'l is a view partially in section showing a typical "built-up grooved work roll constructed in accordance with the invention.

Referring now to Fig. l, a winding drum is shown at I which may be of a suitable known type of construction secured to a foundation as at il and adapted to be power driven through gearing as at I2. This drum may be provided with clamping means of a suitable known type as at I3 for securing the end of the stock 9 to the winding drum. The stock 9 may be pulled by this drum from a reel or pay-out block as at i4, through a pair of the rolling heads as indicated at I5 and I6. As shown, each of these rolling heads may include a pair of work rolls as at I1, I8 and I1', I8', preferably of the small built-up grooved type above referred to. Each of these work rolls may be backed or cradled by a pair of backing rolls asat I9, 20 and I9', 20', or as at 2.I,.22 and 2|', 22.

Since the rolling heads I5 and I6 may be the same or similar in construction except for the desired differences in the form of the grooves for the work rolls, Figs. 3-6 inclusive will serve to illustrate the constructional features of both. Each of these rolling heads may be contained in a box-like frame as at 23 having a base as at 24 adapted to be bolted to a Ifoundation as at II. The box 23 may contain two pairs of bearing -housings as at 25, 26 and 21, 28, each of said housings being common to the anti-friction bearings for one end of each of two adjacent backing rolls as shown. That is, as apparent from Fig. 3, the bearing housing 25 for example,` serves to carry the upper anti-friction bearings for the two backing rolls I9, 20, and the bearing housing 21 similarly carries the anti-friction bearings for the two backing rolls I9', 20'. Similarly the bearing housings 25 and 28 respectviely carry the anti-friction bearings for the backing rolls I9, 2U and I9', 20. The bearing housings 25 and 25 `with the bearings and work rolls associated therewith, may be slid into place in the box structure 23 as shown, and removably secured as by bolts 29. The bearing housings 21, 28 with the bearings and backing rolls I9', 20 in association therewith, are adapted to be slidably received in the box structure 23 and so as to be adjustable toward or away from the stock 9. To af.- ford such adjustment, the bearing housings 21, 28 may be backed by a plate member 30 adapted to be engaged by set screws as at 3|, carried in a side wall of the box structure 23. The bearing housings 21 and 28 may be also held in proper spaced relationship at their corners with strips as at 32, 33 removably bolted in place as shown and accurately shaped for slidably engaging the side walls of the box structure 23 so that upon adjustments of the positions of the bearing housings, the same will be accurately slidable in a direction at right angles to the strip. f

The anti-friction bearings for the backing rolls may all be of the same or a similar construction such as shown in Fig. 6. As here shown,

for example, the backing roll I9' is formed with short rigid upper and lower necks 34, 35 journaled in anti-friction roller bearings as at 38, 31. The necks 34, 35 may extend with a smaller diameter as at 33, 38 Vinto anti-friction thrust bearings as at 43, 4I enclosed in bearing rings as at 42, 43.

A pair of bars as at position by screws as shown,

44', 45 may be held in across the top of roll may be readily .built-up having a central 'be shaped to correspond to the two comple- .ment. The side walls of the box structure 23 yif desired therethrough.

while the invention has been` described m de- 42, etc., against displacement vertically from the box structure `while still permitting the bearing assemblies for the backing rolls I8', 20' to be slidably adjusted toward and away from the stock.

The work rolls, a typical one of which is shown in Fig. '1, may comprise a stud-like cylindrical center piece as at 46, formed with a ange as at 41 near one end and threaded near the other end as at 48 for receiving a clamping nut as at 49. Several disc or washer-like members as at 50 forming the built-up construction of the work roll, may be clamped as shown between the flange 41 andnut 49. If for exampleit is desired that the stock be rolled with a hexagonal cross section, then a middle disc of smaller diameter may be provided as at 5I having an outer cylindrical surface. 'I'his disc may be flanked by somewhat larger discs 52, 53 having a part of their outer surfaces of cylindrical form and partially beveled as shown at an appropriate angle. The discs 52, 53 may be flanked by two more discs as at 54, 55 having cylindrical outer surfaces. By using discs of varying diameters and with different forms of peripheral surfaces, in this way it will be apparent that the work groove of the'desired cross section to correspond to the special shape of the stock to be rolled, and the grooved area will be flanked by a pair of adjacent cylindrical areas for contacting with the backing rolls, so that the work roll will be self-aligning and held accurately in position as it rotates, by the backing rolls.' The work rolls of one of the rolling heads may be thus formed with grooves corresponding respectively to two quarters of the cross sectional outline desired to be imparted to the stock, whereas the V*gbvesm of the work rolls of the other rolling head may mentary quarters of such outline. These builtup work rolls in accordance with this invention are not provided with roll necks adapted for journaling the rolls, although as shown in Fig. 7, the central stud member 46 may be extended somewhat as at 56, 51 merely to provide means for centering anti-friction thrust bearings as at 58, 58 respectively (Fig. 5). That is, the work rolls are free in radial directions to assume positions determined by the two cradling backing rolls against which the work roll is thrust under pressure of the stock as pulled through the mill in contact with the work roll grooves. The antifriction bearings as at 58, 59 on the work rolls merely serve to prevent endwise movement ofthe work rolls and to thus retain the grooves of the cooperating pair of work rolls in proper relationship to each other and to the stock.

The anti-friction thrust bearing assemblies at 58 and 59 may be received and held in place within suitably shaped cut-out portions as at 60, 6I, 62, 63, of the bearing housings 21, 28, 25, 25 respectiveLv. 'I'hat is, a substantial portion of the side walls of these bearing assemblies, as wall as portions of the outer'faces thereof, may be embraced within these cut-out portions so that the work rolls are held against endwise displacemay be formed with openings as at 64 (Fig. 4) to permit the stock 8 to be introduced through the rolling head and freely pass back and forth BEST AVAILABLE COPY 4 tail with respect to a particular preferred example, it will be understood by those skilled in the art after understanding the invention that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appendedclaims to cover allsuch changes and modifications.

What is claimed as new and desired to be secured by Letter' Patent is:

1. In apparatus-.for cold rolling and drawing metal rod and thelike to a predetermined crosssectional shape, a cooperating pair of superposed undriven reducing rolls formed respectively with circumferential grooves of cross sections substantially corresponding to complementary portions of the outline of said shape, a pair of axially spaced undrivenl and anti-frictionally journaled backing rolls for each of said reducing rolls, each reducing roll being freely cradled between and supported inl free rolling contact against its associated pair of backing rolls, and means for pulling the stock between said pair of reducing rolls in working engagement with the grooved portions thereof.

2. In apparatus for cold rolling and drawing metal rod and the like to a predetermined crosssectional shape, a cooperating pair of superposed relatively small reducing rolls, at least oneof which is formed with a circumferential groove of a cross section substantially corresponding to a portion of the outline of said shape, a pair of axially spaced, undriven and anti-frictionally journaled backing rolls for each of said reducing rolls, each reducing roll being freely cradled between and supported in. free rolling contact against its associated pair of backing rolls, and means for pulling the stock between said reducing rolls.

line of said shape, another and succeeding cooperating pair of superposed undriven relatively small reducing rolls also formed with circumferential grooves of cross sections substantially corresponding to remaining complementary portions of the outline of said shape, a pair of undriven anti-frictionally journaled and axially spaced backing rolls for each of said reducing rolls, each reducing roll being freely cradled between and supported in free rolling contact against its associated pair of backing rolls, and means for pulling the stock between said pairs of reducing rolls successively in working engagement with the grooved portions thereof.

4. In apparatus for cold rolling and drawing metal rod and the like to a predetermined cross# sectional shape, a. cooperating pair of superposed, relatively small, undriven reducing rolls, at least one of which comprises. a plurality of disc-like members of different diameters retained in faceto-face relationship upon a stud to thereby form a circumferentially grooved Working surface of a cross section substantially corresponding to portions of the outline of said shape, a pair of axially spaced backing rolls for each of said reducing rolls, each reducing roll being freell cradled between and supported in free rolling contact against its associated pair of backing rolls, and means for pulling the stock between said reducing rolls.

l RICHARD G. BENNEWITZ.

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