US3355925A

US3355925A - System for dynamically adjusting the working roll separation in rolling mills

Info

Publication number: US3355925A
Application number: US405749A
Authority: US
Inventors: Peter J Barnikel; Robert P Freedman
Original assignee: General Dynamics Corp
Current assignee: General Dynamics Corp
Priority date: 1964-10-22
Filing date: 1964-10-22
Publication date: 1967-12-05
Anticipated expiration: 1984-12-05
Also published as: DE1427895A1; ES318732A1; DE1427895B2

Description

1967 P .1. BARNIKEL ETAL 3, 5,

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLING MILLS Filed Oct. 22, 1964 4 Sheets-Sheet l INVENTORS.

PETER J. BARNIKEL a ROBERT F? FREEIDMAN @ME L, mam

their ATTORNEYS 5, 1967 P. J. BARNIKEL ETAL 3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLING MILLS Filed Oct. 22, 1964 4 Sheets-Sheet 2 INVENTORS. PETER J. BARNIIKEL 8 ROBERT F? FREEDMAN their ATTORNEYS 5, 1967 P. J. BARNiKEL ETAL 3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLING MILLS Filed Oct. 22, 1964 4 Sheets-Sheet 15 wk N R Q m wt mm wQm mN INVENTORS. PETER J. BARNIKEL 8 ROBERT P. FREEDMAN BY W 9m, wzw

their ATTORNEYS 1967 P. J. BARNIKEL ETAL 3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLING MILLS Filed Oct. 22, 1964 4 Sheets-Sheet 4 INVENTORS. PETER J. BARNIKEL 81 ROBERT P. FREEDMAN their ATTORNEYS United States Patent 3,355,925 SYSTEM FOR DYNAMICALLY ADJUSTING THE ROLL SEPARATION IN ROLLING I Peter J. Barnikel, New London, and Robert P. Freedman,

Waterford, C0nn., assignors to General Dynamics Corporation, New York, N.Y., a corporation of Delaware Filed Oct. 22, 1964, Ser. No. 405,749 9 Claims. (Cl. 72-244) This application is a continuation-in-part of our copending application Serial No. 182,062, filed March 23, 1962, for Actuating Device and now abandoned.

This invention relates to systems for controlling the separation of the working rolls in rolling mills during mill operation and, more particularly, to a new and improved dynamic roll separation adjusting system capable of very accurate roll adjustment at extremely rapid rates.

Prior to the introduction of the modern tandem mill to the metal processing industry, it was not necessary to adjust the separation of the working rolls during operation of a rolling mill and the only adjustments which were made were of the preset type. Initially, such preset adjustments were accomplished by driving tapered steel wedges between the roll bearing blocks and the mill frame with the aid of a sledge hammer, the wedges being retained in place by friction when a load was applied to the rolls. Later, to provide a wider range of adjustment of the preset roll separation, hand-operated screws were substituted for the wedges, thereby providing a bi-directional control to improve the accuracy of setting the roll separation, and eventually, electrically-driven presetting screws were substituted for the manually-operated screws. As in the case of the wedge, the high friction between the screw and its nut was effective to preserve the separation setting when the rolling load was applied. At about the same time, it was proposed to make the original steel wedge bidirectionally adjustable by replacing the sledge hammer with a lead screw; but this proposal was never put into practice.

With the advent of tandem rolling it became necessary to provide adjustment of the separation of the working rolls with metal in the mill in order to maintain the constant mass flow which is required by the tandem proc: ess. To permit this adjustment, the electric adjusting screw presetting motors were replaced with must larger electric motors which could be jogged to overcome the friction that had previously served so well to hold the preset roll separation during operation. More recently, in response to an ever-increasing demand for higher quality rolled strip material, attempts have been made to regulate the gauge of the finished strip with greater accuracy by adjusting the roll separation in a controlled manner during rolling of the strip in response to measured gauge variations. Accordingly, the previously large electric screw motors, which were incapable of providing continuous roll separation adjustment at rapid response rates, were replaced by even larger screw drive motors, supplemented by more sophisticated motor controls and antifriction bearings. Because of the very large mass required in the rotor of the electric drive motor and the connecting gear train, the maximum response rate which it is possible to obtain with such systems corresponds to a working roll acceleration in the order of 0.1 inch per second per second, but the correctional demands of high speed rolling mills can require accelerations up to five to ten times that which is possible with the electrically driven screw. Consequently, when automatic gauge control is attempted with electrically driven screws, a number of mill stands having dynamic separation adjustment control must be used for correction, since only a small fraction of the total correction is attainable in each stand.

One attempt to overcome these ditficulties is described in United States patent to Wheeler No. 2,961,901, where in the nuts for the two adjusting screws of the rolling mill are provided with gear segments which are simultaneously rotated by a hydraulically driven rack. Although this arrangement provides some improvement in working roll adjustment acceleration over the electric motor-driven screws, it still does not approach the maximum control requirements of modern rolling mills for automatic gauge control because of the high inertia of the nut system and the very high flow rate required of the geared-down hydraulic drive system.

Accordingly, it is an object of the present invention to provide a new and improved system for adjusting the working roll separation during operation of a rolling mill which overcomes the above-mentioned disadvantages of the prior art.

Another object of the invention is to provide a new and improved dynamic roll separation adjusting system which responds rapidly enough to permit complete automatic gauge regulation of the material being rolled in a single mill stand.

A further object of the invention is to provide an adjusting system of the above character which is simple and efiicient in operation, may be installed easily in conventional rolling mill stands, and is capable of providing highly accurate roll separation settings.

These and other objects of the invention are attained by providing, in a rolling mill stand having a fixed frame and a pair of working rolls, one of which is adjustable relative to the other one in the plane of the working roll axes soas to vary the roll separation, a wedge member interposed between the adjustable roll and the stand frame, hydraulic piston means connected to the wedge member to impart motion thereto prependicularly to the direction of relative motion of the adjustable working roll, and a layer of polytetrafluoroethylene interposed between each of the wedge surfaces and the frame and the adjustable working roll, respectively. Preferably, the layer of polytetrafluoroethylene is in the form of a fabric made of fibers of polytetrafluoroethylene so as to withstand the extreme pressures generated in a rolling mill while providing almost ideal anti-friction characteristics.

More particularly, the stand of the invention is preferably provided with two separate adjusting systems interposed between the stand frame and a bearing chock at each end of that backup roll which applies pressure to the adjustable working roll. Within each adjusting system are a backup wedge which is complementary to the movable wedge and a bearing plate, both having surfaces which coact with the movable wedge surfaces and both of which are provided with a removable insert plate upon which the layer of polytetrafluoroethylene is mounted. Moreover, inasmuch as the backup wedge must move perpendicularly to the direction of motion of the movable wedge and must have good lateral support without permitting lateral motion, guide members coated with a poly: tetratluoroethylene surface are provided to guide the backup wedge in its motion. Furthermore, to assure proper alignment of the components of the adjusting device despite Wear of the polytetraflu-o-roethylene layer and manufacturing variations, the hydraulic piston is linked to the wedge member by a tie rod which extends through a central opening in the piston and holds the piston against the adjacent end of the wedge member. 1

Further objects and advantages of the invention will be apparent from a reading of the following description in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a rolling mill stand provided with a representative roll separation adjusting system according to the invention;

FIG. 2 is an end view of the mill stand shown in FIG. 1, looking from the right-hand side of FIG. 1 and partly broken away;

FIG. 3 is an enlarged fragmentary view in longitudinal section, taken along the line 33 of FIG. 1 and looking in the direction of the arrows, illustrating the adjusting systern in greater detail; and

FIG. 4 is a plan view, partly in section, taken along the line 4--4 of FIG. 3 and looking in the direction of the arrows.

In the typical embodiment of the invention illustrated in the drawings, a rolling mill stand includes a rigid frame 11 in which are mounted, as best seen in FIG. 2, a lower backup roll 12, a lower working roll 13, an upper working roll 14, and an upper backup roll 15, all of the usual type. Within each side of the frame 11 the lower backup roll is supported in a lower bearing chock 16 (only one being visible in FIG. 2) and each side of the lower working roll is supported and guided in a smaller bearing chock 17 which fits into a corresponding opening in the chock 16. Similarly, at each side of the frame the upper backup roll is supported in a bearing chock 18 and each side of the upper working roll 14 is guided by a small bearing chock 19 which is received in a corresponding opening in the chock 18, each of these bearing chocks being mounted for vertical sliding motion in the usual manner so as to permit adjustment of the working r-oll separation.

As in convention-a1 mill stands, an electric screwdown system 20 is mounted at the top of the frame 11 in order to make any large scale separation adjustments which may be necessary before or between mill operations. This system includes the usual drive motor 21 along with a reduction gear system 22, a worm gear 23, a splined screw 24 and a lubricated nut 25 above the upper backup roll bearing chock 18 at each side of the frame 11 and, in conventional apparatus, the screw 24 would hear through a breaker block directly upon the bearing chock 18.

In order to provide a highly accurate adjustment of the separation of the

working rolls

13 and 14 during operation with a high acceleration rate in accordance with the present invention, however, a rapid response hydraulically actuated adjusting mechanism 26 is inserted between the screw 24 and the bearing chock 18 on one side of the frame 11 and an identical adjusting mechanism 26' is inserted between the screw 24' and the bearing chock 18' on the opposite side of the frame. Inasmuch as the two adjusting mechanisms and the associated apparatus are identical, only the left hand system 26 as viewed in FIG. 1 will be described in detail, corresponding parts of the other system being identified by primed reference characters.

As shown in the enlarged views of FIGS. 3 and 4, the rapid response adjusting mechanism 26 comprises a vertical support plate 27, on one side of which a horizontal rectangular frame 28 and two

vertical reinforcing plates

29 and 30 are attached by welding, for example, the

plates

29 and 30 being connected to the frame 28 by two

horizontal plates

31 and 32. On the other side of the vertical plate 27 a hydraulic cylinder 33 includes a piston 34 attached to a hollow central shaft 35 which projects through both of the end Walls 36 and 37 of the cylinder. A tie rod 38, extending through the central opening of the hollow shaft 35, has an enlarged head 39 hearing against one end of the shaft 35 through a thrust washer 40 and, at the other end of the shaft, the tie rod is threaded into a socket 41 connected by a neck portion to one end of a rectangular wedge member 42, the rim of the socket 41 engaging the shaft 35 through a spacer 43 and another thrust washer 44. With this mounting arrangement, slight variations in the position of the wedge member 42 with respect to the piston 34, which may result from manufacturing variations or from wear in the layers of polytetrafiuoroethylene which are described below, can be accommodated to prevent the binding of the wedge 42 and piston 34 which would occur if they were constrained to exact alignment.

The cylinder 33 is arranged to receive hydraulic fluid on either side of the piston 34 through two

conduits

45 and 46, as shown in FIG. 2, so as to be double acting with regard to the direction of control. Hydraulic fluid is supplied to the

conduits

45 and 46 from a conventional control unit 47 wherein fluid from a high pressure line 48 is supplied to one or the other of the

conduits

45 and 46 by a conventional control valve (not shown) within the unit 47 in accordance With a control signal applied by a cable 49, the fluid being returned from the control unit through another conduit 50. Preferably, the hydraulic system including the

conduits

45 and 46, the internal control valve in the unit 47, and the cylinder 33 are capable of handling hydraulic fluid at pressures up to about 4,000 psi. or higher.

In addition, to provide a control signal regulating the operation of the control unit 47 a control system (not shown) which may be of the type described in the copending application of Freedman, Barnikel and Torrance, Serial No. 150,738 filed Nov. 7, 1961 and now Patent No. 3,197,986 entitled Control System for Rolling Mills is provided. As described in that application, the working roll force required to attain a desired reduction in the thickness of the material is determined in advance of rolling from a variety of factors such as the thickness of the incoming material to be rolled, the temperature of the material, the tension of the strip of material entering and leaving the mill, the velocity of the material passing through the mill, etc. and is compared with the actual force applied by the mill and a corresponding control signal is applied at the proper time to a Wedge control unit to produce the required force. Accordingly, a control signal, obtained in that manner or in any other appropriate manner and corresponding to the change in force required to produce the desired thickness reduction is applied to the control unit 47 through the cable 43 so as to control the direction in which hydraulic fluid is applied to the cylinder 33. Inasmuch as there are two adjusting

systems

26 and 26, one for each side of the rolling mill, the necessary force to be applied to each side of the backup roll and working roll may be determined separately and the systems '26 and 26' actuated separately, thereby enabling variations in temperature, incoming thickness, etc. which occur between one side of the mill and the other to be taken into account.

In order to provide a signal which represents the position of the wedge at any instant, a linear potentiometer 52 is mounted at the side of the reinforcing plate 29, as shown in FIG. 4. A potentiometer control rod 53 connected to the wedge 42 by an extension rod 54 moves with the wedge so as to cause the potentiometer 52 to produce in the cable 51 a control signal accurately representing the position of the wedge. In the method of operation just described, wherein the necessary force is computed and compared with the actual force and the wedge is moved so as to produce the desired force, the Wedge position signal is used only to control the initial position of the wedge when the mill stand is being prepared for operation. If desired, however, in other methods of oper-- ation, the signal from the potentiometer 52 will be com-- pared with a desired wedge position signal to control the position of the wedge.

In the typical embodiment illustrated in the drawings, the adjusting system 26 is releasably attached to the screw 24 while permitting rotation of that screw, by a horizontal bearing plate 55 which is affixed to the top of the rectangular frame 28 and has a control circular recess 56 to receive a flange 57 at the lower end of the screw. The flange 57 is retained by an inwardly projecting lip 58 which extends around one half of the periphery of the recss 56 and a locking plate 59, slidably mounted in the top bearing plate 55, which is movable toward and away from the screw 24 so as to be extendable over the opposite edge of the flange 57. To operate the locking plate 59, a lever 60, pivotally mounted on the top bearing plate 55 by a stud 61, is linked to the plate by a pin 62, and an actuating arm 63 slidable through an aperture in the support plate 27 is connected to the lever 60 at an elbow 64, as shown in FIG. 4. A releasable locking member 65 is provided in the plate 27 to retain the actuating arm and the lever in the position corresponding to the closed position of the locking plate.

Below the laterally movable wedge 42, a backup wedge 66 is supported between the members of the rectangular frame 28 and a crossbar 67, retaining plates 68 being mounted on the crossbar 67 and the frame 28 to limit the downward travel of the backup wedge and retain it within the adjusting assembly. In the illustrated rolling mill stand a clearance hole 70 is provided in the backup wedge 66 to accommodate a pin 69 which projects from the top of the upper backup roll chock 18.

r In order to overcome the frictional resistance to motion, which heretofore had defeated all previous attempts to use wedges for dynamic rolling mill adjustments no matter how well the wedges were lubricated with conventional lubricants, it is essential that an antifriction layer of a material having extremely low coefficients of static and sliding friction be retained between the coacting surfaces of the movable wedge 42, the bearing plate 55, and the backup wedge 66. Moreover, although the polytetrafiuoroethylene material which is made by the E. I. du Pont de Nernours and Co. and is sold under the trademark Teflon has been used in solid or sheet form to provide very low coeflicients of static and sliding friction, its tendency towards cold flow or plastic deformation makes it undesirable as a bearing material for unit loads exceeding about 3,000 p.s.i.

It has been discovered, however, that the tensile strength of polytetrafluoroethylene fibers is many times that of the solid or sheet form of the material. Conse quently, when polytetrafiuoroethylene fibers are woven into a fabric they form a surface having the lubricating properties of solid polytetrafluoroethylene but capable of withstanding loads of more than 20,000 p.s.i. without cold flow. One form of fabric which may be used for this purpose comprises a composite weave of polytetrafluoroethyh ene fibers with other fibers as described in the United States Patent to White No. 2,804,886. It has been found, however, as described in the copending application of Edward Hobaica, Serial No. 395,468 filed Sept. 11, 1964, now Patent No. 3,283,718, and assigned to the same assignee as the present application, that a fabric made entirely of p-olytetrailuoroethylene fibers may be bonded to a clean metal surface by chemically etching one face of the polytetrafiuoroethylene fabric, applying an adhesive material having an affinity for metal to the metal surface, placing the etched fabric surface on the adhesive covered metal surface, and applying heat and pressure to bond the fabric to the metal surface. For a more detailed description of the bonding method, reference may be had, if necessary, to the above-mentioned Hobaica application. In addition, it has been found that fabrics made entirely of polytetrafluoroethylene fibers having a wearing quality superior to that of the composite fabric. Alternatively in certain cases, the polytetrafluoroethylene material may be held in a metallic matrix of the type described, for example, in United States patent to Love No. 2,798,005 or may consist of a filled polytetrafluoroethylene sheet of the type sold by the Dixon Corporation of Providence, Rhode Island under the trade name Rulon, in order to form the antifriction layer.

In the illustrated embodiment of the invention both the bearing plate 55 and the backup wedge 66 are provided with

insert plates

71 and 72 respectively at the surfaces facing the wedge 42 and each of these plates has bonded to its outer surface a

layer

73 and 74 respectively of the above-mentioned polyt-etrafluoroethylene fabric. These insert plates are retained in corresponding recesses in the bearing plate and the backup wedge by a plurality of set screws 75. Also, to permit vertical motion of the backup wedge 66 while resisting the laterally directed force component the crossbar 67 has mounted on the side adjacent to the backup wedge a guide shim 76 having a polytetrafiuoroethylene fabric bonded to its working surface in the manner previously described. Furthermore, to guide both the movable wedge 42 and the backup wedge 66 along the sides adjacent to the rectangular frame 28,

similar shims

77 and 78 having polytetrafluoroethylene fabric surfaces are mounted on the frame members. Consequently, metal to metal contact of the movable wedge and the backup wedge during operation is completely eliminated and those wedges engage only surfaces which have extremely low coefficients of static and sliding friction. In addition, flexible rubber seals 79 mounted on the rectangular frame 28 and the crossbar 67 engage the sides of the backup wedge 66 and sheet metal covers 80 and 81 are mounted above and below the space between the

vertical plates

29 and 30 to keep the interior of the adjusting assembly 26 free of dirt.

In operation, with a layer of material to be rolled passing between the working rolls 13 and 14 and with the screw 24 preset at a desired setting, a signal representing any change in the force which is required to produce a desired reduction in the thickness of the material is applied through the cable 49 to the control unit 47. In response to this control signal, the internal valve (not shown) in the control unit moves to supply hydraulic fluid from the line 48 to one or the other of the

conduits

45 and 46 to move the piston 34 in the proper direction to reduce the difference between the actual force applied and the required force. As the wedge 42 moves to the left as viewed in FIG. 3, for example, it drives the backup wedge 66 downwardly, thereby increasing the pressure applied by the working rolls 13 and 14 so as to reduce the thickness of the material being rolled, and, as the wedge moves to the right the pressure is reduced so that the thickness of the material is not decreased to as great an extent.

By virtue of the very small mass, in contrast to conventional apparatus, of the movable members of the adjusting system 26 including the piston 34 and the wedge 42, the roll separation adjusting system of the present invention is enabled to make roll separation adjustments at very high acceleration up to, for example 0.8 inch per second per second while controlling the separation very accurately, e.g., to less than three ten-thousandths of an inch. in fact, the accelerations attainable with the piston and wedge arrangement of the present invention re not limited by the inertia of the components being driven and any reasonable acceleration may be provided. In contrast, as pointed out above, conventional electrically driven screw controls are limited to about 0.1 inch per second per second maximum acceleration and the hydraulically actuated screws described in Patent No. 2,961,- 901 are limited to about 0.3 inch per second per second maximum acceleration by the system inertias. Stated another way, the inertias of a comparable wedge adjusting system of the present invention, a hydraulically driven screw system, and an electrically driven screw system are in the ratios of one to one hundred to one hundred thousand. Also, in addition to having a mass which is negligible compared to the driving force available and a static friction which is about the same as its sliding friction, the coefficient of friction of the polytetrafluoroethylene antifriction layer utilized in the present invention varies with the velocity of the wedge in such a way as to approach true viscous damping, which is highly desirable in high speed servo mechanisms.

Exemplary of the high performance capabilities of the adjusting system of the present invention is the fact that an adjusting system of the type described herein, subjected to a total load of over two million pounds and a pressure in the range of 5,000 to 10,000 p.s.i. on the polytetrafiuoroethylene bearing surfaces was operated with continuous adjustment motion at varying rates for over 1400 hours without failure, consistently providing accurate adjustments at accelerations far exceeding those attainable with conventional apparatus.

Although the invention has been described herein with reference to a specific embodiment, many modifications and variations therein will readily occur to those skilled in the art. Accordingly all such variations and modifications are included within the intended scope of the invention as defined by the following claims.

We claim:

1. Apparatus for adjusting the working roll separation in a rolling mill including a frame and first and second relatively movable working rolls disposed within the frame comprising a wedge member having two surfaces disposed at an angle interposed between the frame and the first working roll and movable transversely therebetween so as to increase or decrease the force urging the first working roll toward the second working roll, a first bearing member linked to the mill frame and having a bearing surface coacting with one of the surfaces of the wedge member, a second bearing member linked to the first working roll and having a bearing surface coacting with the other surface of the wedge member, an antifriction layer including polytetrafiuoroethylene disposed between each of the surfaces of the wedge member and the coacting surfaces of the first and second bearing members respectively, and hydraulic drive means including a piston connected directly to the wedge member to impart said transverse motion thereto, including removable insert plates mounted in the first and second bearing members to provide the bearing surfaces thereof, and means affixing the layer including polytetrafiuoroethylene to each of the insert plates so as to dispose it between the coacting surfaces of the wedge member, and the first and second bearing members.

2. Apparatus for adjusting the working roll separation in a rolling mill including a frame and first and second relatively movable working rolls disposed within the frame comprising a wedge member having two surfaces disposed at an angle interposed between the frame and the first working roll and movable transversely therebetween so as to increase or decrease the force urging the first working roll toward the second working roll, a first bearing member linked to the mill frame and having a bearing surface coacting with one of the surfaces of the wedge member, a second bearing member linked to the first working roll and having a bearing surface coacting with the other surface of the wedge member, an antifriction layer including polytetrafluoroethylen disposed between each of the surfaces of the wedge member and the coacting surfaces of the first and second bearing members respectively, and hydraulic drive means including a piston connected directly to the wedge member to impart said transverse motion thereto, including a hollow shaft on which the piston is mounted, and a tie rod extending through the hollow shaft and attached to the wedge member to hold one end of the shaft in rigid abutment with the wedge member but permit positional adjustments in the plane of abutment.

3. Apparatus for adjusting the working roll separation in a rolling mill including a frame and first and second relatively movable working rolls disposed within the frame comprising a wedge member having two surfaces disposed at an angle interposed between the frame and the first working roll and movable transversely therebetween so as to increase or decrease the force urging the first working roll toward the second working roll, a first bearing member linked to the mill frame and having a bearing surface coacting with one of the surfaces of the Wedge member, a second bearing member linked to the first working roll and having a bearing surface coacting with the other surface of the wedge member, an antifriction layer including polytetrafluoroethylene disposed between each of the surfaces of the wedge member and the coacting surfaces of the first and second bearing members respectively, and hydraulic drive means including a piston connected directly to the wedge member to impart said transverse motion thereto, wherein the second bearing member is wedge-shaped to complement the shape of the wedge member, and including support means supporting the second bearing member for motion perpendicular to the transverse motion of the wedge member and guide means in the support means having a polytetrafluoroethylene surface to provide lateral support for the second bearing member while permitting said perpendicular motion thereof.

4. Apparatus for adjusting the working roll separation in a rolling mill including a frame and first and second relatively movable Working rolls disposed within the frame comprising a wedge member having two surfaces disposed at an angle interposed between the frame and the first working roll and movable transversely therebetw-een so as to increase or decrease the force urging the first working roll toward the second Working roll, a first bearing member linked to the mill frame and having a bearing surface coacting with one of the surfaces of the wedge member, a second bearing member linked to the first working roll and having a bearing surface coacting with the other surface of the wedge member, an antifriction layer including polytetrafluoroethylene disposed between each of the surfaces of the wedge member and the coacting surfaces of the first and second bearing members respectively, and hydraulic drive means including a piston connected directly to the wedge member to impart said transverse motion thereto, including screw leans mounted in the mill frame and having a movable end to provide large scale adjustments in the Working roll separation and locking plate means releasably locking the first bearing member to the movable end of the screw means to provide said link to the mill frame.

5. A rolling mill comprising a mill frame, first and second relatively movable working rolls disposed within the frame, and a pair of adjusting means interposed between the frame and each end of one of the working rolls, respectively, each adjusting means comprising a Wedge member having two surfaces disposed at an angle interposed bctween the frame and the first Working roll and movable transversely therebetween so as to increase or decrease the force urging the first working roll toward the second working roll, a first bearing member linked to the mill frame and having a bearing surface coacting with one of the surfaces of the wedge member, a second bearing member linked to the first Working roll and having a bearing surface coacting with the other surface of the wedge member, an antifriction layer including polytetratluoroethylene disposed between each of the surfaces of the wedge member and the coacting surfaces of the first and second bearing members respectively, and hydraulic drive means including a piston connected directly and rigidly to the wedge member to impart said transverse motion thereto.

6. A rolling mill according to claim 5 wherein each of the first and second bearing members has a removable insert plate to provide the bearing surface thereof and wherein the layer including polytetrafinoroethylene comprises a fabric including fibers of polytetrafiuoroethylene bonded to each of the insert plates.

7. A rolling mill according to claim 6 wherein each of the adjusting means includes a hollow shaft on which the piston is mounted and a tie rod extending through the hollow shaft and attached to the wedge member to hold one end of the shaft in rigid abutment with the wedge member but permit positional adjustments in the plane of abutment.

8. A rolling mill according to claim 7 wherein the second bearing member of each adjusting means is wedgeshaped to complement the shape of the wedge member,

and each adjusting means includes support means supporting the second bearing member for motion perpendicular to the transverse motion of the Wedge member and guide means in the support means having a polytetrafiuoroethylene surface to provide lateral support for the second bearing member While permitting said perpendicular motion thereof.

9. A rolling mill according to claim 8 including a pair of screws mounted in the mill frame each having a movable end directed toward a corresponding end of the first Working roll to provide large scale adjustments in the Working roll separation, and locking plate means in each adjusting means releasably locking the first bearing member of the adjusting means to the movable end of the corresponding screw to provide said link to the mill frame.

References Cited UNITED STATES PATIENTS 1,821,483 9/1931 Shover et a1. 72--244 2,798,005 7/1957 Love. 2,804,886 9/1957 \Vhite. 3,081,644- 3/1963 Hud-gens et al 74-4243 3,197,086 8/1965 Freedman et a1 72244 FRANCIS S. HUSAR, Primary Examiner.

Claims

1. APPARATUS FOR ADJUSTING THE WORKING ROLL SEPARATION IN A ROLLING MILL INCLUDING A FRAME AND FIRST AND SECOND RELATIVELY MOVABLE WORKING ROLLS DISPOSED WITHIN THE FRAME COMPRISING A WEDGE MEMBER HAVING TWO SURFACES DISPOSED AT AN ANGLE INTERPOSED BETWEEN THE FRAME AND THE FIRST WORKING ROLL AND MOVABLE TRANSVERSE THEREBETWEEN SO AS TO INCREASE OR DECREASE THE FORCE URGING THE FIRST WORKING ROLL TOWARD THE SECOND WORKING ROLL, A FIRST BERARING MEMBER LINKED TO THE MILL FRAME AND HAVING A BEARING SURFACE COACTING WITH ONE OF THE SURFACES OF THE WEDGE MEMBER, A SECOND BEARING MEMBER LINKED TO THE FIRST WORKING ROLL AND HAVING A BEARING SURFACE COACTING WITH THE OTHER SURFACE OF THE WEDGE MEMBER, AN ANTIFRICTION LAYER INCLUDING POLYETRAFLUOROETHYLENE DISPOSED BETWEEN EACH OF THE SURFACES OF THE WEDGE MEMBER AND THE COACTING SURFACES OF THE FIRST AND SECOND BEARING MEMBERS RESPECTIVELY, AND HYDRAULIC DRIVE MEANS INCLUDING A POSTION CONNECTED DIRECTLY TO THE WEDGE MEMBER TO IMPART SAID TRANSVERSE MOTION THERETO, INCLUDING REMOVABLE INSERT PLATES MOUNTED IN THE FIRST AND SECOND REMOVING MEMBERS TO PROVIDE THE BEARING SURFACES THEREOF, AND MEANS AFFIXING THE LAYER INCLUDING POLYTETRAFLUOROETHYLENE TO EACH OF THE INSERT PLATES SO AS TO DISPOSE IT BETWEEN THE COACTING SURFACES OF THE WEDGE MEMBER, AND THE FIRST AND SECOND BEARING MEMBERS.