US3076360A

US3076360A - Clam shell cold rolling mill

Info

Publication number: US3076360A
Application number: US756574A
Authority: US
Inventors: Sendzimir Tadeusz
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-08-22
Filing date: 1958-08-22
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05
Also published as: FR1361899A; GB988196A; CH425698A; BE627714A; DE1187580B

Description

4 Sheets-Sheet 1 Feb. 5, 1963 T. sENDzlMlR CLAM SHELL COLD ROLLING MILL Filed Aug. 22. 1958 E Mf il? 1 Feb. 5, 1963 T. sENljzlMlR 3,076,360

. CLAM SHELL COLD ROLLING MILL l Filed Aug. 22. 1958 4 Sheets-Sheet 2 INVENTOR TAm-:Usz SENDziMiQ Flgu 3 l ATTORNEYS.

Feb. 5, 1963 T7 sENDzlMlR 3,076,360

CLAM SHELL COLD ROLLING MILL Filed Aug. 22. 1958 4 sheets sheet 3 2f ze' f 26' 26 afsz Savez/Mae, BY

@flaw @flag ATToRNEYs.

Feb. 5, 1963 T. sENDzlMlR CLAM SHELL COLD ROLLING MILL 4 Sheets-Sheet 4 Filed Aug. 22. 1958 INVEMTOR. 72050.52 e'Naz/M/f, BY

ATTQRNE'YS.

United States Patent Oilice 3,076,360 CLAM SHELL COLD ROLLING MILL :Tadeusz Sendzimir, SendzimirfCogQxford Circle,

Waterbury 12, Conn. .FiledAug 22, 1958, Ser. N0. 756,574

' 'tsfclaims (CLso-,stn

The Linvention relatessto niillsffor cold rolling strip materials,-ihe mills being of thelgeneral type disclosed in U.S. Patent 2,776,586. Such mills are `beam-type mills, characterizedby' greatrigidity coupled with the ability to use small working rolls, which are evenly and rigidly backed allacross the width of the strip being rolled. Thus heavy reductionscan be `made on work-hardening materials, and alsofstrips may be rolled to an accuracy impossible to attain in other `types of equipment. i

Such millsarequite expensive to build. `For one thing, the mill housing '(as can be seen in FIG. 8 of the above noted patent) is a solid casting, pierced in one horizontal direction by a passageway for the strip, and having an opening in the otherhorizontal direction, which contains the operating instrumentalities of `the mill. This opening has to be very accurately machined all over its inside surfaces, the machining consisting for the most part in the precision boring of eight semi-circular trough-like conguratioris which, aside from being accurate "in diameter, must jbe parallel with each other with lextreme accuracy.

` :Such Vhousings maybe made on spo-called precisionhoriz ontal boring mills, requiring weeks of work on an expensiveA machine tool, followed by weeks of laborious hand` scraping to attain the minimum limits `of accuracy. Specially designed inside boring tools, where the parallelism of the `individual troughs `is insured by the accuracy of the tool itself, could be used, and the necessity of `hand-scraping avoided. But the c ost of such tools lis high, and a separate boring machine would be required for each type and size of mill, so that vamortization costs are excessive.

For another thing, the interior construction of the mill is `complicated by the fact that `eccentric mountings for the so-called casters have to be provided for screwdown purposes.

` A Vprimary.object of the invention is to provide a mill ofthe general type of that shown in Patent 2,776,586, which will V"have a housing substantially as accurate and rigid as the housing ofthe patented mill, and which will permit the use of working rolls of as small a diameter and as well supported, but which can be built at a substantially lessercost'. It is an object of theinvention to provide a mill in which the interior mechanism is more readily accessible for replacement or repair. It is an object vrof the invention to provide va mill in which a much wider rollopening can be attained. y

It is an object of the invention to provide a mill of the type designated which has a` simplerinterior construction.

"It is an'obje'c't of the yinvention to provide a mill charac# teriZed by new ways of compensating for deection.

It is an object of theinvention to provide a millhaving a simpler screwdown.

These Yand other objectslof the invention, which will' be set forth hereinafter `or will be apparent to one skilled in the art upon reading these specifications, are accomplished by`that certain constructionv and arrangement of parts of which an exemplary embodiment will now be described. Reference ismade to the accompanying `drawings wherein:

FIG. lis a side elevational view ofthe mill of this invention.

` FIG..2a is an elevational view showing another mode of connecting the hydraulic cylinder to thelower housing member. d

FIG. '2b `is` a partial end elevation ofthe Vm'illtaken .from theleft side of FIG. 11.

uF1620 is a partial end elevationof the-milltaken from the right side of FIG. l. s i

FIG. 3 is a partial end View, and FIG.4, a partial plan View of the table of a machinetool illustrating a mode 'of manufacture of the housing members `of the `mill Aof the present invention.

FIG. 5 is a longitudinal section :of the mill proper.

FIG. 6 is a transverse sectiontaken through'the mill proper along the section line 6-6 of FIG. 5.

VIt has hitherto been suggested that the housingv of `amill, such as is shown in Patent 2,776,586, could `be made in upper and lower sections, the sections being vhingedtogetheriat one side, and held together by adjustable means at the other side, which means could serve as a screwdown. However, a beambacked mill of this character is not .the full equivalent of a-mill having a -solid or one-piece housing. One reason for this is that the four vertical columns at the `sides of a mill having a one-piece housing, being integral with the beams themselves, have a substantial eiect in resisting deflection, and exert -a controlling effect on the manner in which deilection takes place. As a consequence, while it will be obvious that Yif the upper `half of a mill housing could be swung back with respect to the lower half, or even removed entirely therefrom, the interior components of the mill would be more accessible, a satisfactory construction embodying separable housing parts has not hitherto been provided.

IThe manner in which these and other problems have been `solved in the present invention will be made vclear after `a brief description `of the organization of the mill.

Referring lto FIGS. V1 and 2, the mill of this invention comprises an upper housing part 1 and a lower-housing part 2. The lower half of the mill housing rests upon and is bolted to Va suitable foundation, which is preferably in the form of a box of hollow construction 3, since vcertain elements of the mill, as will hereinafter appear, vextend below the lower housing element 2.

The upper mill housing element 1 rests upon the lower housing element at one end by means of a hinge construetion indicated generally at 4. This construction is termed a hinge because the upper mill housing element pivots on it for screwdown purposes; but it need not be such ahinge as would enable the top portion of the mill housing to be swung out of the way,'or through an angle of 90 or 180 on the hinge. Furthermore, the hinge has an important function in maintaining the alignment of the upper housing portion of the mill with the lower housing portion. The hinge as illustrated in FIG. 1 comprises two adjust# able block members 4a and 4b with approaching surfaces bearing cylindrical hollows indicated at 4c and 4d, `and a cylindrical member 4e engaged in these hollows. In describing the mill of this invention, the term ends willbe used to designate those portions which lie inthe direction of rolling, the face portionsof the mill which lie at 96 thereto being referred to as the .sidesf At the other end of the

mill housing elements

1 and 2, a screwdown mechanism 5 is provided (see FIGS. 1 and 2b).

A fluid pressure cylinder 7 engages the under side of the lower housingelement 2, its piston rod 8 acting against a lower platen 9Ato which it is Vpreferably swiveled as:indi cated at 10 in FIG. l. The lower platen is connected by four tie rods indicated at 11, 12 and 13 tothe upper'housing element 1. The fourth tie rod is not shown in the drawings, but itsposition will be understood from the position of the others. The tie rods may be held to the lower platen by-nuts or in any other suitable fashion; but the upper ends of the tie rods will be provided with enlarged heads 14 pivoted to ear portions of the upperhousing member by pintles 15. This construction, together with the swivel connection 10, will permit 4a tilting of the upperv housing element 1 such as may be requiredfor` screwdown Patented Feb. 5, 17963v purposes. The pintles may be removable, so that the entire upper portion of the mill, including the housing member 1, may be lifted off the lower portion and carried away, as by means of a crane.

It will be understood from the figures that the tie rods, the hinge constructions, and the interengaging portions of the screwdown are located toward the sides of the mill, so as to permit passage of the strip 16 which is to be rolled.

The fluid pressure cylinder 7 is connected through suitable valve controls to an hydraulic system (not shown). So long as the force exerted by the cylinder 7 is greater than the roll separating force encountered during the rolling operation, pressure will be exerted on the hinge constructions 4 and on the screwdown constructions 5. Under these circumstances, the

mill housing portions

1 and 2 will be accurately positioned because the preload eliminates all chances of play and of misalignment. Also, they will act in a more rigid manner, as hereinafter explained.

If, on the other hand, the roll separating forces should at any time exceed the hold-down force of the hydraulic cylinder 7 (as for example when a piece of metal too thick for a given pass is fed into the mill through error), the two

housing portions

1 and 2 will part slightly either at the hinge construction 4 or at the screwdown device 5, or both, thereby relieving the working and supporting rolls as well as the bearing elements of the mill from overload, and preventing damage to the mill.

As has been indicated above, the characteristics of rigidity in a mill having a two-piece housing are not identical with those of a mill having a one-piece housing. The four integral, short, vertical columns of a one-piece housing have a relatively heavy section, and help to rigidify the mill through their own resistance to bending as Well as through their rigid connection with the upper and lower beam elements. They act effectively to reduce deflections due to bending of the beam elements both in a direction perpendicular to the rolling direction, and in the direction of the strip being rolled.

Deflection of the beam members in the direction of movement of the strip is of little consequence, both in magnitude, and in influence on the accuracy of the mill and the accuracy of the product being rolled therein. This is chiefly because such deflection is uniform all across the width of the strip, is largely compensated for by the action of the screwdown, and is practically negligible in magnitude when compared to other deflections in the mill such as the flattening of rolls under pressure.

Deflection in the mill at right angles to the length of the strip is, however, a matter of substantial concern, because such deflection has as its ultimate consequence the bending or deflection of the working rolls. Such a deflection will cause the distance between the working rolls to be greater in an area corresponding to the center of the strip, and smaller near the edges of the strip. The rolled product will, therefore, be variable in gauge across its width.

The mill of this invention, having as has been described

separable housing elements

1 and 2, has certain inherent characteristics of rigidity in the side-to-side direction. The hinge elements 4 and the screwdown elements 5, as will be most apparent from FIGS. 2b and 2c, have a substantial width. lf the upper housing element 1, as a result of rollseparating forces in the mill, should tend to deflect as a beam, its side portions 17 and 18 (as indicated in those figures) would tend to rotate counterclockwise and clockwise through minute angles corresponding to the deflection of the beam. The line indicated at a represents a horizontal plane through the end portion 17 of FIG. 2b. If the upper housing element 1 deflects as a result of roll separating forces in the mill, the center portion would bow upwardly tending to rotate the side portion 17 downwardly in a counterclockwise direction as shown in exaggerated fashion by the dotted line a'. A similar line b in FIG. 2c represents a horizontal plane through the side portion 1S. The dotted line b illustrates in an exaggerated fashion the counterclockwise rotation of the side portion 18 that would be caused by such a beam deflection. Such rotation will be opposed by the action of the

elements

4 and 5 because these elements are under pressure, and the pressures would be concentrated toward the outer portions of these elements. The total pressures do not change, and therefore the elements 4 and S tend to prevent deflection across the mill, which deflections are further minimized by the action of the

tie rods

11, 12 and 13 which, it will be noted, are so located as to coact with the

elements

4 and 5 in creating torques which are opposed to the type of mill deflection under consideration.

The construction of the mill in accordance with the present invention makes it possible to create an elasticity factor to counteract or offset beam deflection in a direction across the mill. This can be explained as follows:

In a beambacked mill having a one-piece housing, the roll separating forces are transmitted to the four vertical columns of the mill housing in the form of tensional stresses. In contradistinction, in the mill of this invention, where the two halves of the housing come together, i.e. at the hinge elements 4 and the screwdown elements 5, the condition is one of compression. As has been indicated, the tie rods 11 to 13 exert a downward pull on the upper housing element 1 which is greater than the normal roll separating force. The tie rods can all be elements of high tensile strength material and rather highly loaded, because their own elongation under tension is of no consequence, so far as the accuracy of the mill is concerned.

The cylinder 7, which exerts the pressure on the lower platen 9 by which the tensional forces are transmitted to the tie rods 11 to 13 inclusive, is affixed to the center of the lower housing element 2. Thus, it will tend to deflect the lower housing element 2 in directions opposite to those in which the roll separating forces tend to deflect it. Thus, a deflection of the upper housing mem ber produced by the roll separating forces can be accomplished for by a deliberately produced deflection of the lower housing element 2 produced in the way just described. There are various Ways in which this compensation can be controlled. In the first place, the forces exerted by the fluid pressure cylinder 7 can be increased or diminished, so long as their value continues to be greater than that of the roll separating forces. The ability of the lower housing portion 2 to deflect under any given stresses can be controlled in the design of the mill by increasing or diminishing the cross section of the lower housing. It will be noted in the drawings hereto appended that the upper mill housing element 1 has been given a large cross sectional area so as to minimize transverse deflection, while the lower mill housing element 2 has a lesser cross sectional area to permit a compensating dellection produced by the cylinder 7.

In most cases, the general relationship between the effective area of the cylinder 7 and the relative rigidity of the lower housing element 2 will be such that counterdeflection of the lower mill housing element will suffice as a corrective measure, making the mill much easier to operate, particularly in the selection and development of appropriate profiles in the strip material being rolled. The deflection of the lower mill housing element 2 can be increased under any given pressure exerted by the fluid cylinder 7 by slightly crowning that base of the cylinder assembly which is aflixed to the flatly machined bottom of the housing element 2. This will concentrate the pressure in the center of the housing element; and when this is done, the bolts 19, which aflix the cylinder to the housing element 2, may be loosened so that the deflection of the housing element will depend upon the force exerted by the cylinder 7 rather than on the tightening force of the bolts.

For very wide mills, i.e. those designed to roll strips from 50 inches to 100 inches and wider, measures such as those just described for minimizing total mill deflection by introducing other deflections which, when opposed to the inevitable natural deflection ofthe upper housing, even out the deflection across the strip, are of great importance.

In very wide mills it is `often preferable, instead of using a single point of reaction of the cylinder 7 against "the lower mill housing, to employ two or more points of application of the force that urges the two mill parts together. One way of doing this is illustrated in FIGURE 2a. Here the hydraulic cylinder 7 does not bear directly against the lower mill housing 2, but upon thecentral por Vtion' of a beam 79 extending parallel with the work rolls,

the beam having near each end` abut-,ment screws 80 and 81 which contact the lower mill housing at spacedpoints `and transmit the pressure of thev cylinder thereto. The distance between these abutment screws is preferably less than one-third of maximum width of strip accommodated by the mill; and of course they should be symmetrically disposed.

lt will be seen from the above` explanation that this `invention provides for the first time a controlled rigidity in a beambacked mill having a housing made in separable parts. It also provides means for compensating for deection in such a mill. With these provisions, it becomes feasible to construct the mill housing in two parts, and hence to take advantage of a mode of machining the interior surfaces of themill which involves a great lowering of cost. This mode of manufacture is illustrated in FIGS. 3 and 4. In this mode of manufacture, both portions of the

mill housing

1 and 2 are clamped on the table 20 of a precision machine tool. If the two housing portions are of the same eiective thickness, their machined backs may rest directly on the table. If one housing element is thinner than the other, it will rest on the table through the intermediary of a suitable machined block `for the purpose of equalizing the heights. The clamping `will be done in such a way that the positions of the four trough-shaped configurations of each mill housing section will be disposed in alignment as continuations of each other. As is usual in machining operations, a template may be positioned on the table to guide the cutting. The four trough-shaped configurations are indicated in FIG. 3 at 22, 23, 24 and 25.

The machine tool may be any suitably accurate ltype of planer-miller, a milling machine, or even a precision planing machine having an accurately guided table. A tool is used which is centered at the end of each stroke on the surface of the template 21, and metal may be removed from both

housing sections

1 and 2 in a concurrent operation with perfect assurance of parallelism of the trough-shaped configurations.

A machine tool operator of even moderate experience can readily follow the outline of the template 21, for example, with a half-round nose milling or other cutter, thus producing perfectly machined inner surfaces. Methods have now been developed to do this completely automatically, so that the only discrepancy or deviation from parallelism which is encountered in the nishedproduct arises from the wear of the tool itself during any one pass. This is negligible since the attempted accuracy is ofthe order of from something less than `0.0001 to 0.0002 in., depending upon the size of the mill.

While stress has been laid above on the semi-circular trough-like configurations in the interior of the mill, which contain the saddles for the casters, there are other elements which must be accurately aligned in order to assure a parallel registration of the

mill housings

1 and 2. This applies to the serrations which serve to locate the hinge blocks, hereinafter more fully described, and the troughs which serve to locate the shafts or bearings forthe shafts which are involved in the screwdown mechanism 5. The serrations are indicated in FIGS. -3 and 4 at 26, and the last mentioned troughs in FIG. 3 at 27,. The machining method hereinabove described permits the formation of these configurations at thel same time and in Substantially the Same Way as the trough-like @Misurations 22' to 25 `discussed hereinabove. Thus, complete parallelism is attained here also, together with avery substantial saving in cost.

As best shown in FIGS. 1 and 5, each hinge element comprises an upper block 28 and a lower block 29, these blocks having on their rear surfacesa vseries of machined serrations mating with the serrations 26 hereinabove de,- scribed. The blocks are held to the

housing members

1 and 2 by a series of

bolts

30 and 31 which pass through slots in the blocks. The approaching ends of the blocks are somewhat reduced as shown, and are recessed to receive the actual hinging element or pintle 4. The ser.- rated structure which has been described permits the blocks 23 and 29 to be fastened to the

housing members

1 and 2 in adjusted positions. Thisis to say thatfor the tolti-ng of thicker materials a greater separation between the

housing elements

1 and 2 may be ldesired at the righthand end of the mill in FIG. 1 and vice versa. The construction is also of value in compensatingfor Iwear; and for changes in diameter of rolls, as where rolls are dressed or exchanged. The screwdown hereinafter described takes care of the actual roll separation during the operation of the mill; but the mill is conveniently adjusted for overall thicknesses by means of the hinging construction. The hinge ldesign permits the use of blocks and pins, both of which are made of relatively hard materials; and the diameter of the pintle 4 may be relatively small so'that its pivoting action, when opening and closing the roll bite of the mill, can be relatively frictionless. The hinge construction preserves the alignment of the'mill housings in the direction of rolling so long as there is pressure between the'two housing elements. Lateral alignment of the two parts of the housingY can be accomplished in various ways. The tie `rods 11 to 13, passing through A-perforations in the lower housing element 2, ten-d to preservea general lateral alignment even though they are `freely movable in the perforations. A more precise align- Vin bearings located in the troughs 27 hereinabove described, ,and heldin place by means of bolted

retainers

36 and 37. These shafts are each provided with eccentric portions 3S and39, located near the sides ofthe mill, and out of theopath of the strip 16 whichris being rolled. The eccentrics are preferably made in one piece with the shafts 32 and-`33.

In FIG. 3 there is shown alever arm splined to the Shaft 33. This lever arm is pivoted to the piston rod 4d of anthydraulic cylinder 42, the opposite end of which is connected to the mill housing as at 43. It will be understood that actuation ofthe cylinder 42 lwill. rock the, Yshaft 33, actuating the eccentric portion thereof, and forcibly separating the

shafts

32 and 33. The shaft 33 is preferably provided with an hydraulic actuator at each side of the mill. y f' l The treatment of the upper shaft 32 may be similar, in` that it may be provided with its own lever arms and hydraulic actuators attached tothe upper half of the mill housing. However, there lare otherfway's of treating the upper shaft. In FIG. 2 the left half. of the drawing has been reversed, for the purposeof showing the eccentric screwdown means instead of the hinge. Here the eccen tries are again indicated` at 3S and 39; but the

shafts

32 and 33 are indicated as geared together by gear elements 44 and 45. When this is done, and when the hydraulic cylinders 42 are actuated, the

shafts

32 and 33 are forced to rotate in opposite directions. Obviously, the largest displacement will be secured when the two eccentrics are in symmetrical relationship to each other, but other combinations are possible to suit the operator. l

The screwdown arrangement which has been described is negative in the sense that when actuated it `forces the

housing members

1 and 2 apart at one end, these parts ao'faseo pivoting on the pintles 4 at the other end. This type of screwdown is possible so long as the mill housings are under pressure from the hydraulic cylinder 7. The screwdoiwn effect is attained with great accuracy and simplicity; and cost is saved in the interior of the mill because it is not necessary to provide eccentricity in connection with the saddles for screwdown purposes.

The screwdown mechanism has been described above as though the

shafts

32 and 33 extended across the entire mill. Such a construction is not necessary, and separate short shafts may be provided at each side of the mill housing members, the short shafts being controlled as hereinabove described. When such a construction is adopted, the screw-down arrangements at each side of the mill will not be mechanically interconnected; and another advantage is secured, namely, the use of a slightly asymmetric setting, where desired, within the limits of the elastic deflection of the

housing elements

1 and 2. In this case each cylinder should have its own independent hydraulic valve (servo valve).

Within the accuracy limits that are realized in rolling fiat strip on the type of mill hereinabove described, there is never any need for large variation in the setting of the right side in relation to the left side of the mill. A difference of, say, 0.0001 in. is quite noticeable. But it does happen in practice that a slight differentiation in pressure and setting of the mill is desirable; and it can be obtained on the mill herein described, whereas it cannot be obtained in a solid housing mill such as is described in Patent 2,776,586 referred to above.

An exemplary internal arrangement for a mill of the present invention is indicated in FIGS. 5 and 6. The two halves of the mill are the same, so that they can be described in common. The working rolls 46 are of very small diameter, and they rest each against a pair of intermediate rolls 47. -For convenience herein, these rolls are called the first intermediate rolls. They rest against a series of three larger second intermediate rolls 48. The second intermediate rolls in each half of the mill are backed by a set of four casters. The supporting portions of these casters may be in the form of very heavy outer races 49 of roller bearings mounted on shafts 50. The casters on each shaft are spaced lengthwise of the shaft, as most clearly shown in FIG. 6. Between the casters, the shafts 50 are supported by saddle members 51, which saddles in turn bear -on the surfaces of the semi-circular machined troughs of the housing members heretofore described and designated by the index numerals 22 to 25. On the shafts the casters are grouped in assembly, each caster being disposed between two of the saddle members 51. All of the saddle members and the inner races of the caster bearings are held axially compressed on the shafts 50, as by nuts threaded on the ends of the shafts.

From FlG. 5 it can be seen that the saddle members have portions shaped to fit the semi-circular troughs, and other portions shaped to abut against or to clear saddle members in adjacent troughs. In this manner all of the saddles 51 can be oriented in the same manner, and so located that they do not interfere with neighboring assemblies. The nuts on the ends of the shafts 50 compress the inner races of the casters 49 so that they will not rotate by themselves; but during the course of the use of any mill, these inner races may be rotated from time to time, usually by about one-third of a revolution so as to get the full life out of the structures. It will be understood that the shaft-holding portions of the saddles are all ground to the same inside diameters, and that the saddles themselves have the same outside diameters. Hence, they provide a spaced backing (with accurately machined casters) for the second intermediate rolls, and ultimately for the working rolls. Since screwdown is not accomplished in this mill by means of eccentric saddles or eccentric saddle shafts, the construction of the saddle and caster assemblies is substantially simplified and cheapened.

For other details of construction of beambacked cold rolling mills, and ways in which they can be adequately lubricated and cooled, reference may be made not only to Patent 2,776,586, noted above, but also to such United States Patents as 2,566,679 and 2,479,974.

In a simple mill of the type herein being described, an adjusting means may be provided as indicated in FIG. 5. This adjusting means comprises screws such as the screw 52, threaded in the housing, and bearing against a saddle member 53. Each such screw may be fitted with a sliding head 54 which has precision marks to show its angular position. Means are provided whereby each such screw can be engaged by a wrench or other turning device; and the screws are preferably provided with locking means (not shown) to inhibit accidental changes of rotative position. One such screw is provided for each saddle in an outer saddle assembly of at least one housing assembly ofthe mill. The screws 52 are disposed approximately in the line of greatest pressure of the saddles against the trough surface of the beam in which they are housed, which line of pressure in the outer saddle assemblies of the exemplary mill herein illustrated, lies very nearly in the horizontal plane. The screws 52 are employed to adjust or control the crown or shape of the mill. In operation, the screws are not intended to lift the respective saddles entirely off their seats, but only slightly to relieve the pressure of the saddles against the seats, within the elastic limits of the parts. Turning any of the screws 52 inwardly will result in putting more pressure on the saddle contacted by that screw than on neighboring saddles, which is the way in which the crown or shape of the mill is adjusted, whenever such adjustment is necessary. In more elaborate and expensive beambacked mills, more elaborate means have been devised for mill adjustment; but in the relatively inexpensive mill of this invention, the adjustment means above described has been found adequate.

Another desirable simplification has been found practical in the mill of this invention, namely, the application of the main mill drive to the center roll only of the second intermediate backing roll series. Hitherto it has been found necessary or advisable to drive all or a plurality of the backing rolls of the second series, as in Patent' 2,776,586. Surprisingly, it has been found that a mill drive applied only to the center roll of the second intermediates series is satisfactory in the mill of this invention; disadvantageous slippage does not occur. It will be evident from FIG. 5 that a driving force applied to the center roll of the second intermediate series, not only transmits its torque by friction to the first intermediate rolls, and thence to the working rolls, but also transmits torque to the casters, and through the casters to the outer ones of the intermediate rolls of the second series. But the success of the simplified drive taught herein is believed to be more directly due to the following consideration: If two rolls of each second intermediate series are driven, it becomes necessary to grind each pin of the driven rolls with great accuracy to the same diameters. If this is not done, all of the drive will be concentrated on the roll which has the larger diameter; and the smaller roll in the same series may actually drag or resist the drive. Such a situation does not occur when only the center rolls of the two second intermediate series are driven. These rolls do not have to have exactly the same diameter as other intermediate rolls in the same series, and while the one driven roll in the second intermediate series should have substantially the same diameter as the one driven roll in the other second intermediate series (the other half of the mill), a small discrepancy in diameter only slightly alters the position of the socalled non-slip point of the metal being reduced in the roll bite, which is not a serious disadvantage. Despite a small discrepancy in their diameters, each directly driven roll has substantially the same share in the transapre-,36o

`9 mission of driving force to the mill; and the rolls do not ywork against each other.

In FlG. 6 the two middlejintermediate rolls of the `second series (marked 48,) -are'shown ,as provided with

thrust bearings

55 and 56 lat one of their ends, and elongated at the other of their ends (as at 57 and 5S) so that connections may be made therewith .by means of driving 'and `thrust-sustaining

spindles

59 and 60 with Va pinion stand (not shown) which will be powered in any suitable way, as by an electric motor.

`At eachl side of .each ofthemilhhous-ing members, there :may tbe, provided removable plates illustrated in FIG. 6 .at :61, -62 63a `and 6,4, The

plates

6,1 and 62 carry

vthe thrust bearings

55 and 56 for the rolls in each second intermediate series.

AS. was taught in Fatent 2.776.586., more perfect rolling is accomplished `in rigid bsambacked mills by prov-iding one -or bothof the rolls `of the first intermediate yseries `with slight taper-reliefs, so located that they start `inside the edges of the material being rolled and Vextend `outwardly therebeyond. In that patent also. there was `discl-osed the expedient of providing taper reliefs near or at the ends of atleast a pair of intermediate rolls, `but at `opposite ends of the respective rolls, and then adjusting `the rolls by relative longitudinal movement until these `taper reliefs were brought into the relationship with the edges of the material being rolled which has been described above. In this way the mill could `readily be adjusted for the rolling of materials of different widths, `without changing the rolls of the first intermediate series A.each time the width of rolling material was changed.

The same effect is accomplished in .the mill of this invention in a much simplified manner. The simplification is based on the discovery, after long experimen tation, that it was not detrimental to the rolling operation to shift the `working rolls 46 along with the rs-t series intermediate rolls 47 in an axial or longitudinal direction.

lThe simplification is effected by placing the working roll and its adjacent supporting rolls of the first intermediate series in each half of the mill in a common drawen The drawer elements are indicated at 65, 66, 67 `and 68 in FIG. 5. They comprise not only theillusltrated elements extending across the mill in spaces between the supporting rolls and the work piece, but also end elements indicated in FIG. 6 `at 69, 70, 71 and 72. The intermediate rolls of the first series and the work rolls are either journaled in or have a thrust bearing against these end elements, the drawers thus constituting frames which are capable of being moved transversely of `the mill.

Bracket elements

73 and 74 are lattached respectively to the end mill plate 61 `and 62; and these `brackets bear threaded

shafts

75 and 76,. The end elements 71 and 72 of the respective drawers are provided with `fittings 77 and 78 (FIG. 6), each including a nut portion which is threaded -on one of the shafts 75 or `,76. By turning either of these threaded shafts, its entire drawerincluding the working roll and the two intermediate rolls of the first series may be moved laterally of the mill. It will be understood that at least one of the supporting rolls` of the first series in the upper half of the mill will have a taper relief near one of Vits ends, `and that at least one of the supporting rolls of the rst intermediateseries in the lower half of the mill will `have a taper `relief adjacent its other end.I The positions of `these tapered reliefs can be adjusted by turning the threaded `

shafts

75 and 76 so as to bring the tapered reliefs into coincidence with the edges of material being rolled, `when the width of these materials is changed. The threaded shafts arein a position of convenient access on `.the -operators side of the mill which makes it possible to observe the exact axial position of each drawer. The -ttings `"I7 and 78 may conveniently carry pointers mov- `ing over `scales to indicate -the exact positions in the mill of the taper reliefs.

-In the new arrangement, it is possible to use working rolls devoid of any crown, along with taper-relieved inter.-

-hereinabove described, and since adjustment may also be effected by the use of independent screwdowns at each side of the mill. Crowned working rolls may, however, `be used if desired.

Those portions of the drawers which extend across the mill and are generally indicated at 65, 66, 67 and 68 in FIG. 5 may be shaped or enlarged in such fashion as to be disposed in a floating position on the first intermediate rolls 47 and the outer ones of the second intermediate rolls 48. These portions of the drawers are preferably lined with `an anti-friction, usually plastic, material. They may be urgedslightly against the rolls aforesaid by any suitable spring elements. The longitudinally extending drawer portions, or members attached to them, may be `Prforated or made hollow for the delivery of lubricant to the mill. They lare provided with suitable perforations to form jets of the lubricant, which is also a coolant.

Lubricant may be directed against the working rolls as theycontact the piece being rolled, and it may alsorbe injected between the casters into the space between the vari-ous supporting rolls so as to work -t-oward the workingrolls.

The locationV of the jets 4and the introduction of lubricant is important since this constitutes a means for maintaining the wheat balance of the mill, and of avoiding undue cXpansion of any of the mill elements from an unequal rise of temperature. As a rule the discharge of cooling lubricant should be greater toward the cen-ter of `the rolls than near the edges of the strip being rolled; but

the exact number of jet-forming holes and their positions will depend on the type of mill, its size, the material being rolled, and other factors. The lubricant normally issues from the mill at the level of the strip being rolled, .and may be filtered `and recirculated in any suitable fashion. Oil issuing from themill may be arranged -to be caught in the foundation box 3.

lt will be observed that the mill of this invention is not provided with doors ateither side. This gives greater space for the passage of lubricant and coolant.

The interior portions of the mill of this invention are unusually accessible. The hydraulic cylinder 7 may be so constructed and operated that it will lift the upper half of the mill to any desired height. The hinge construction and the screwdown construction, as will be evident, are separable vertically since they are required to sustain only compressive forces. Means for retaining the working roll and the intermediate rolls of both sets, together with the casters and saddles, `are easily provided in a mill lof this type so that if the upper half of the mill is raised for access to its interior, the positions of these elements will not change. A lifting 'of the upper half of the mill by means of the hydraulic cylinder 7, the lower platen 9 and the tie rods 11 to 13 is suicient for all ordinary jobs of replacement and repair; but as indicated above, by disconnecting the tie rods, the entire upper housing member together with its appurtenances may be removed from the mill `and transported elsewhere.

Modifications may be made in the invention without `departing from -the spirit of it. Having thus described the invention in an exemplary embodiment, what is claimed as new and desired to be secured by Letters Patent is:

l. A gbeambacked mill for rolling flat products,` comprising two separable beams, each having rotatable inner elements adapted to back a working roll throughout its working length, said beams having corner portions extending beyond the working length of the said working rolls, means interposed between the corner portions of the two beams at one side of said working rolls for maintaining said corner portions apart by a desired distance, said means acting as hinges for said beams, adjustable separators interposed between the corner portions of the two smesso beams at the opposite side of said working rolls, and pressure means for urging the two beams toward each other with a force in excess of the roll-separating force encountered in reducing a work piece between said working rolls, whereby the means interposed between the respective corners of said beams may be maintained under compression during a rolling operation.

2. The structure claimed in claim 1 wherein said pressure means are of yielding character so as to permit separation of said beams under excessive roll-separating force.

3. A beambacked mill comprising two symmetrically disposed and substantially identical backing structures, each comprising a one-piece beam with parallel cavities in which cavities casters are supported for transferring rollseparating forces encountered by working rolls to said beams, said beams having corner portions located laterally of the path of travel of a strip of metal to be rolled between said working rolls, means interposed between the respective corner portions of the two beams for maintaining said beams in separated position, and means urging said beams together with a force greater than the rollseparating force encountered by said working rolls in reducing said strip, whereby to maintain the means interposed between said corner portions under compression.

4. The structure claimed in claim 3 in which the means interposed between the corner portions f said beams at one side of said working rolls are adjustable whereby to provide screwdown.

5. A beambacked mill having two separable parts, each part comprising a beam generally rectangular in plan and having corner portions, a working roll, at least one set of intermediate rolls backing said working rolls, casters journaled in saddles and backing said intermediate rolls, said saddles being mounted in hollows extending from side to side in said beams, said mill parts being disposed in opposition to each other with said work rolls in alignment, an hydraulic cylinder and piston means engaging the outer central portion of the beam of one of said mill parts and the central portion of a platen, said platen having corner portions connected respectively by rods with corner portions of the beam of the other of said mill parts, said hydraulic cylinder and piston means being capable of exerting a force urging said mill parts together and greater than the roll separating forces exerted on said Working rolls during a rolling operation, separable abutment means interposed between the corner portions of said beams at one end of the mill and negative, continuously adjustable screwdown means interposed between the corner portions of said beams at the other end of said mill.

6. The structure claimed in claim 5 wherein said hydraulic cylinder and piston means are swiveled to the central portion of said platen, and in which said rods are pivotally connected to the corner portions of the beam of the said other of said mill parts.

7. The structure claimed in claim 6 in which the beam of the said other of said mill parts is of greater thickness than the beam of the mill part to which the hydraulic cylinder and piston means are attached, whereby a deflection of the beam of the said other of said parts due to working roll separation forces will be compensated at least in part by the deection of the beam of the opposite mill part due to the pressure exerted on the central portion of the last mentioned beam by the said hydraulic cylinder and piston means.

8. The structure claimed in claim 7 wherein the said negative screwdown means comprises at least one eccentrically mounted shaft on each corner portion of an end of at least one of said beams and bearing on members attached to the corresponding corner portions of the other of said beams and means for adjusting and fixing the rotative portions of said shafts whereby to effect a negative screwdown.

9. The structure claimed in claim 8 wherein the abutment means connecting the corners of said beams at the opposite end of said mill each comprise abutment means 12 adjustably attached respectively to the `corner portions of said beams, said abutment means having approaching surfaces bearing cylindrical hollows, and a cylindrical member engaged in the hollows of approaching ones of said abutment members to provide a hinging action.

10. The structure claimed in claim 8 including lever arms non-rotatably affixed to said eccentrically mounted shafts and hydraulic cylinder and piston means connected to said lever arms and to a support whereby said lever arms may be rocked and held in adjusted position.

11. The structure claimed in claim 10 wherein said abutment members have a toothed engagement with corner portions of said beams whereby to provide for stepwise adjustment.

i2. The structure claimed in claim 11 wherein said eccentrically mounted shafts and said abutment means including said cylindrical members have substantial length in the side-to-side direction of said beams, and in which said rods are pivoted to corner portions of the beam of the said other of said mill parts at a position intermediate the ends of said eccentrically mounted shafts and abutment means, whereby said negative screwdown means and said abutment means tend, under the stresses exerted by said hydraulic cylinder and piston means, to maintain the corner portions of said beams in parallelism with each other to minimize beam deflection in the side-to-side direction.

13. The structure claimed in claim 12 wherein each mill part has a first set of two intermediate rolls and a second set of three intermediate rolls, and wherein the mill drive is applied to the central roll of the second set of intermediate rolls in each mill part.

14. The structure claimed in claim 13 wherein one at least of the intermediate rolls of each first set is provided with a taper relief adjacent one of its ends at a position such that the said taper relief can be brought into coinciidence with an edge of a piece being rolled in the mill.

15. The structure claimed in claim 13 wherein the first intermediate rolls together with a working roll in each of the mill parts are provided with thrust bearings in a member slidable transversely of the mill, at least one of the first intermediate rolls of one mill pa-rt having a taper relief near its end and at least one of the first intermediate rolls of the other mill part having a taper relief near its opposite end, and means for moving said sliding members adjustably, whereby to bring said taper reliefs into coincidence with opposite side edges of varying widths of pieces being rolled.

16. The structure claimed in claim 15 including members threaded into at least one of the said beams so as to bear on the saddles contained at least in one of the hollows thereof whereby to effect a mill adjustment.

17. In a beambacked mill of the type having working rolls, intermediate rolls, casters, and saddles mounted in hollows extending from side to side of beam members extending across the mill, beam members which are separable from each other and which have corner portions, means at the respective corners 0f said beams for holding them apart by a desired distance determinative of screwdown, and means for urging said beams toward each other with a force greater than the roll separating force during a rolling operation, said last mentioned means comprising force exerting means for a reaction against the central portion of one of' the said beams and against the corner portions of the other of said beams whereby defiection in one vof said beams is compensated for at least in part by a ideiiection of the other of said beams in the same direction.

18. in a mill of the type having working rolls, intermediate rolls, casters, and saddles respectively located in hollows in a pair of beams extending in the direction of the length of said working rolls, an elevated platform, said beams being generally rectangular in plan and having corner portions, one of said beams being mounted on said platform by means of its corner portions, an hydraulic 13 cylinder and piston means attached to the center portion of said beam and extending below said platform through a perforation therein, a platen engaging the lower end of said hydraulic cylinder and piston means and rods connesting corner portions of said platen with corner portions of the other of said beams, said last mentioned beam being located above the beam which is attached to said platiiorm, and abutment means located between the respective corners of said beams, the abutment means between the said corner portions at one end of said mill being adjustable for screwdown purposes.

References Cited in the le of this patent UNITED STATES PATENTS 385,437 Baldwin July 3, 1888 1,636,057 .Tones July 19, 1927 1,787,558 Tinsman Ian. 6, 1931 14 Ifobke Sept. 22, 1931 McFadden Jan. 7, 1936 Rohn June 29, 1937 Sendzimir Aug. 15, 1939 Sendzirnir Aug. 22, 1939 Sendzimir Apr. 8, 1941 Larsson Jau. 23, 1945 Sendzimir et al Aug. 23, 1949 Sendzimir et al Sept. 4, 1951 Mock June 15, 1954 Bai-lard Sept. 14, 1954 Sendzimir Ian. 8, 1957 FOREIGN PATENTS Great Britain Nov. 11, 1936 Germany Aug. 25, 1936 France June 27, 1938

Claims

1. A BEAMBACKED MILL FOR ROLLING FLAT PRODUCTS, COMPRISING TWO SEPARABLE BEAMS, EACH HAVING ROTATABLE INNER ELEMENTS ADAPTED TO BACK A WORKING ROLL THROUGHOUT ITS WORKING LENGTH, SAID BEAMS HAVING CORNER PORTIONS EXTENDING BEYOND THE WORKING LENGTH OF THE SAID WORKING ROLLS, MEANS INTERPOSED BETWEEN THE CORNER PORTIONS OF THE TWO BEAMS AT ONE SIDE OF SAID WORKING ROLLS FOR MAINTAINING SAID CORNER PORTIONS APART BY A DESIRED DISTANCE, SAID MEANS ACTING AS HINGES FOR SAID BEAMS, ADJUSTABLE SEPA-