US3438235A

US3438235A - Pre-stressed rolling mill

Info

Publication number: US3438235A
Application number: US579557A
Authority: US
Inventors: Derek A L Elton
Original assignee: Loewy Robertson Engineering Co Ltd
Current assignee: Loewy Robertson Engineering Co Ltd
Priority date: 1965-09-17
Filing date: 1966-09-15
Publication date: 1969-04-15
Anticipated expiration: 1986-04-15
Also published as: DE1527672A1; GB1114778A

Description

April15,fl 9 6 9 D. m. ELTON 3,438,235

FEE-STRESSED ROLLING MILL FiledSepc. 15.1966 Sheet of 4 Y Inventor, DEREK ARTHUR LMBERT ELTON April 15, 1969 D. A. EL ON IPRESTRESSEDROLLING MILL Filed Sept. 15. "1966 I sheet 2 0M I nvenlor A ril 15, 1969 I V D. A. 1.. ELTON 3,438,235

FEE-STRESSED ROLLING MILL v Filed Sept. 15 1966 Sheet om I n venlor DEREK ARTHUR LAMBERT ELTON April 15,1969

FEE-STRESSED ROLLING MILL Filed Sept. 15, 1966 Sheet 4 of 4 Invenlor DEREK ARTHUR LAMBERT ELTON D. A. I... ELTON 3,438,235

United States Patent 3,438,235 PRE-STRESSED ROLLING MILL Derek A. L. Elton, Poole, Dorset, England, assignor to Loewy Robertson Engineering Company Limited, Bournemouth, England, a corporation of Great Britain Filed Sept. 15, 1966, Ser. No. 579.557 Claims priority, application Great Britain, Sept. 17, 1965, 39,866/ 65 Int. Cl. B21!) 31/20, 31/24 US. Cl. 7-2240 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to rolling mills in which the rollbearing chocks of one of two superposed rolls are supported on the bearing chocks of the other roll by spacing means. The spacing means may be arranged between the chocks of either the working rolls or the back-up rolls of the mill, if provided, and they may be adjustable so that the distance between these rolls, and thereby the rollpass opening, can be varied.

In one mill of this type, the spacing means between the rolls chocks are formed by relatively slender screw spindles threaded at one end into the chocks of -a mill roll and resting with their other ends on the chocks of another roll, with the roll-pass opening between both rolls. A rotary drive is provided for the spindles, whereby the chocks of the first roll can be lifted or lowered as required when the setting of the roll-pass opening has to be changed. This design has been adopted for rolling mills whose housings are pre-stressed, e.g., by hydraulic means.

It has been found that in such mills, the pre-set rollpass opening can be kept constant throughout rolling and a rolled article of uniform thickness produced only if the adverse influence of elastic deformations which are bound to occur during rolling in the rolls and in their chocks are eliminated or at least greatly reduced. To this end, the load on the spacing means during rolling is measured by load-meters, and the output of these load-meters fed into electric control circuits which vary the pre-stressing force in such a manner that the desired result is obtained, as described in the British Patent No. 955,124, the loadmeters there being formed by cells which are in contact with screw spindles acting as spacing means for the chocks. It is essential for exact measurement of the loads and effective control of the pre-stressing force that close contact be maintained between the spindles and the loadmeters throughout rolling.

It is an object of the present invention to provide a rolling mill which is equipped with conventional screwdown means for the adjustment of the roll-pass opening, and also with the afore-described arrangement of chockspacing means, so that load-meters may be used in the manner described above for the control of a pre-stressing force.

According to the present invention, a rolling mill having screwdown means arranged between the mill houslugs and the chocks of a roll for the adjustment of the 3,438,235 Patented Apr. 15, 1969 "ice pass-opening between said roll and another roll, spacing means in the form of screw spindles threaded into these chocks and resting on the chocks of the other roll, and a drive for said screwdown means, is provided with movement-reversing means between the screwdown means and said spacing means, whereby the chocks of the first roll and these spacing means are displaced by the same distance but in opposite directions, so that the spacing means remain stationary relative to the chocks of the second roll during displacement of the chocks of the first roll by the screwdown means. Thus, in the case of loadmeters being placed between said spindles and the chocks of said second roll, the contact between the spindles forming the chock-spacing means and the load-meters will not be affected in any way by the displacement of the chocks of the first roll during adjustment of the roll-pass openmg.

The mill according to the invention may be provided with pre-stressing means for the housings and the prestressing force be controlled by the load-meters so as to eliminate or greatly reduce the adverse influence of elastic deformations of the chocks or rolls on the setting of the roll-pass opening as described in the British Patent No. 955,164.

In a preferred embodiment of the invention, the screwdown means and the chock-spacing means are drivably connected to each other by a set of reversing gears which, upon the chocks of the first roll being lowered by the screwdown means, raises the spindles relative to said chocks by the same distance, and vice versa, so that the position of the spindles in space remains unaltered.

The screwdown means may be of any known design and may consist of heavy rotary spindles threaded into the housings and resting on the top of an upper or the bottom of a lower roll. Alternatively, the spindles may be screwed into wedges acting on the chocks, so that upon rotation of the spindles, the chocks are lifted or lowered. In either case, the setting of the roll-pass opening is effected by the spindles of the screwdown means.

The screwdown means and the chock-spacing means may be driven by the same motor or motors and a reduction gear provided between the motor or motors and either means. The reversing gear provided according to the invention may then be combined with that reduction gear.

Alternatively, the screwdown means and the spacing means may be driven from separate motors, the motors being automatically controlled so that they start and stop simultaneously, the drives of the motors being so laid out that the chocks and spacing means are moved by the same distance, but in opposite directions.

The mill according to the invention may have either working rolls only or working rolls supported by backup rolls, and the screwdown means and the spacing means may accordingly act either on the chocks of working rolls or of the back-up rolls.

Several embodiments of the invention will now be de scribed by way of example with reference to the accompanying drawings, in which:

FIG. 1 is a side elevation of a rolling mill according to the invention, partly in section, along the line I-I of FIG. 4. 1

FIG. 2 is a side elevation, again partly in section, along the line 11-11 of FIG. 5.

FIG. 3 is a section along line III-III of FIG. 2.

FIG. 4 is a section through the rolling mill of FIG. 1 along the line IVIV of FIG. 1.

FIG. 5 is a section through the rolling mill of FIG. 2 along the line V-V of FIG. 2.

The rolling mill shown in FIGS. 1 and 4 comprises a base 2 and two housings 4, of which only one is shown,

each housing having a window 6. Two roll-assemblies are mounted in the housings, each assembly comprising a working roll 8 mounted at its end in bearings 9 supported in chocks 10, and a backing roll 12 mounted at its ends in bearings 13 supported in chocks 14. The upper chocks 14 are spaced apart from the lower chocks 14 by supports 16 in the form of screw spindles threaded into recesses 18 formed in the lower part of each of the upper chocks 14, the lower ends of the supports abutting against pressure pads 20. A load meter 22 in the form of a load cell is inserted between each pressure pad and the top of the lower chocks 14. The pads and the load meters are accommodated together in recesses 23 formed in the upper part of the lower chocks 14. Plungers 24 displaceable in hydraulic cylinders 25 are arranged between the chocks 10 of the upper working roll and those of the lower working roll whereby these two rolls are maintained in contact with their respective backing rolls 12.

Each of the lower chocks 14 is mounted on a thrust block 26 in which a hydraulic cylinder 28 is formed, the cylinders being displaceable over rams 30 secured to the lower wall of the windows 6. The pressure of the hydraulic fluid in the cylinders 28 acts both on the upper and the lower parts of the housings 4, whereby the latter are pre-stressed.

The mill so far described is similar to that of British Patent 955,164, the output of the load meters 22 being utilised for controlling the pre-stressing forces in such a manner that the load taken by the supports 16 remains constant during a rolling operation. However, whereas in the mill according to the above-mentioned patent adjustment of the roll-pass opening is effected exclusively by the screw spindles which act as supports for the upper roll assembly, no other roll-pass adjusting means being provided in the earlier mill, the rolling mill according to FIGS. 1 and 4 of the present invention is provided with roll-pass adjusting means in the form of screwdown spindles which pass through the upper parts of the housings 4 and bear with their lower ends against the upper chocks 14. Each spindle 32 is threaded into a bush 34 secured to a housing 4, for instance, by a retaining ring 35. The spindle 32 has further a smooth upward extension 36 which is slidably keyed at 37 to a worm wheel 38. The latter is driven by a worm 40 from a motor, not shown.

As will be clear from the foregoing, the upwardly directed pressure produced in the hydraulic cylinders 28 is taken partly by the spindles 16 and partly by the

rollassemblies

10, 12, the two pressure components being transmitted to the upper chocks 14 and from there through the spindles 32 to the upper parts of the housing 4. During a rolling operation, the load on the spindles 16 is therefore the difference between the pre-stressing force and the roll-separating force, as is also the case with the rolling mill according to British Patent No. 966,164. I

In the rolling mill according to FIGS. 1 and 4, the adjustment of the roll-pass opening is effected in a well known manner by the screwdown spindles 32 which lower or raise the upper chocks 14 by the required amounts. In order to maintain the spindles 16 in contact with the pads 20 during a rolling operation, irrespective of any adjustments of the roll-pass opening, the spindles 16 are raised relative to the upper chocks 14 by the same distance as that by which these chocks are moved towards the lower chocks 14; conversely, the spindles 16 are lowered relative to the upper chocks 14 by the same distance as the latter chocks are moved away from the lower chocks 14. To this end, the worms 40 are integral with or secured to spur gears 42 which are in mesh with pinions provided on shafts 48 which extend freely from the upper parts of the housings 4 and are connected to upward extensions 44 of the spindles 16. The connection is effected by means of links 46 pivoted to the shafts 48 and extensions 44 by pins 47, whereby assembly and dismantling of the spindles 16 from the shafts 48 is facilitated.

The threads on the

spindles

32 and 16 and the ratio of reduction of the gear drive between the two spindles are so selected that the spindles 16 move by the same distance relative to the upper chocks 14 as these chocks are displaced in the opposite direction by the spindles 32. Thus, the spindles 16 remain stationary in space and the contact between the spindles 16 and the pressure pads 20 is not affected by the movement of the upper chocks 14.

The rolling mill shown in FIGS. 2, 3 and 5 is to some extent identical with that of FIGS. 1 and 4, and corresponding parts have been marked in FIGS. 2, 3 and 5 with the same reference numbers as have been used in FIGS. 1 and 4, increased by 1. The mill of FIGS. 2, 3 and 5 has accordingly two housings 104 with windows 106, working rolls 108 with bearings 109 and chocks 110, backing rolls 112 with bearings 113 and chocks 114, supports 116 in the form of threaded spindles, pressure pads 120 and load cells 122, all arranged as described with respect to the rolling mill of FIGS. 1 and 4. Screwdown spindles 132 are threaded into sleeves 134, the latter being housed in recesses of the upper back-up chocks 114. The sleeves are formed at their outsides with worm teeth for rotation by worms 140 (FIGS. 3 and 5) and are prevented from axial movement with respect to the upper chocks 114 by retaining rings 60. Rotation of the screwdown spindles 132 is prevented by keys 61 which are slidable in grooves 62 in the upper chocks 114. Rotation of the sleeves 134 will therefore cause vertical displacement of the spindles 132 and thereby also of the upper roll assembly.

As shown in FIG. 2, the spindles 132 abut against the upper ends of the windows 106.

The drive of the spindles 132 is here combined with the drive for the spindles 116, as will now be described in more detail with reference to FIG. 3. The horizontal shaft 64 supported on the upper part of upper chock 114- carries a helical gear wheel 66 which drives a pinion gear wheel 67 on a stub shaft 68. A worm 70 mounted on shaft 68 drives a worm wheel 72 mounted on the upper extension of one of the spindles 116. Rotation of shaft 68 is transmitted through bevel gears 74, shaft 75 and bevel gears 76 to another stub shaft 78 which latter has a worm 80 driving a worm wheel 82 mounted on the upper extension of the other spindle 116. Both spindles 116 can therefore move together.

The shaft 75 carries also the afore-mentioned worm 140 which drives sleeve 134. The threads on the

spindles

132 and 116 and their ratio of rotation is so selected that the spindles 116 move by the same amount relative to the upper chocks 114 as these chocks are displaced in the opposite direction by the spindles 132. Here again, the spindles 116 will remain stationary in space irrespective of any movement of the upper chocks 114 for rollpass adjustment purposes, so that the contact between the spindles 116 and the pads 120 remains unaffected.

In an alternative embodiment (not shown) the shaft 64 is extended as far as the second stub shaft 78 and provided with a further set of gear wheels for driving the second stub shaft. The worm can then be arranged between the two sets of gear wheels. This makes the shaft 75 and the

gear wheels

74, 76 unnecessary.

The shaft 64 may be driven through articulated spindles (not shown) from an electric motor.

As will be clear from FIGS. 4 and 5, the arrangement shown in FIGS. 1, 2 and 3 is duplicated in respect of each housing. A separate motor may be provided for driving the screwdown spindles in each housing, and means may be provided for synchronizing the speed of each motor so that the spindles of both housings move by equal distances. For this purpose, the output shafts of both motors may be connected, if desired, by a clutch.

The provision of screwdown means makes it possible to displace the upper roll assembly relative to the lower roll assembly by any desired distance, so that the mill according to the invention can be used for reducing relatively thick rolled articles, such as slabs or plates. At the same time, it is possible with the mill according to the invention to effect accurate control of the pre-stressing force as described in British Patent No. 955,164 and in British application No. 245 19/ 63.

I claim:

1. A rolling mill having housings, rolls mounted in said housings, chocks for mounting said rolls in said housings, screwdown means arranged between said housings, and said chocks for the adjustment of the pass-opening between said rolls, spacing means in the form of screw spindles threaded into these chocks and resting on the chocks of the other roll, a drive for said screwdown means and movement-reversing means between said screwdown means and said spacing means, whereby the chocks of the first roll and these spacing means are displaced by the same distance but in opposite directions, so that the spacing means remain stationary relative to the chocks of the second roll during displacement of the chocks of the first roll by the screwdown means.

2. A rolling mill according to claim 1, in which the movement-reversing means consist of reversing gears which drivably connect to each other the screwdown means and the chock-spacing means and which upon the chocks of one of the mill rolls being lowered by the screwdown means relative to the chocks of another roll, raise the chock-spacing means relative to the chocks of the first roll by the same distance as these chocks have been lowered, and vice versa.

3. A rolling mill according to claim 2, in which the reversing gear is arranged between the screwdown means and the chock-spacing means and drivably connected to both.

4. A rolling mill according to claim 2, in which the reversing gear is drivably connected to a reduction gear arranged in the drive of the screwdown means.

References Cited UNITED STATES PATENTS 3,345,848 10/1967 Henschker 72-237 FOREIGN PATENTS 955,164 4/ 1964 Great Britain.

RICHARD J. HERBST, Primaly Examiner.

B. T. MUSTAIKIS, Assistant Examiner.

U.S. Cl. X.R. 72248