US3505849A - Roll stand for a rolling mill - Google Patents

Description

A ril 14, 1970 D. GRUBE 3,

' ROLL STAND FOR A ROLLING MILL Filed Sept. 27, 1967 2 Sheets-Sheet 1 Fig 7 N es April 14, 1970 D. GRUBE ROLL STAND FOR A ROLLING MILL 2 Sheeis-Shee; 2

Filed Sept. 27, 1967 United States Patent O 3,505,849 ROLL STAND FOR A ROLLING MILL Dietrich Grube, Ratingen-Tiefenbroich, Germany, as-

signor to Schloemann Aktiengesellschaft, Dusseldorf, Germany, a company of Germany Filed Sept. 27, 1967, Ser. No. 670,991 Claims priority, application Germany, Oct. 1, 1966, Sch 39,613 Int. Cl. B21b 29/00 US. Cl. 72-215 4 Claims ABSTRACT OF THE DISCLOSURE A roll stand with the working rolls guided along arcuate paths and having swinging backing segments with arcuate section bearing surfaces for backing the working rolls.

The present invention relates to a roll stand for a rolling mill, having co-operating working rolls rotatably mounted in swinging supports for guiding the working rolls along respective arcuate paths, the working rolls being braced against bending during operation.

Roll stands of this kind are known in which the work ing rolls are displaceable in the swinging supports in a direction which is radial to the axis of swing, and are supported by a stationary guide path or track during the working operation, the swinging supports being driven by for instance crank drives.

In such a roll stand, a radial guide way is required for the working rolls, for two reasons; firstly, the guide way must bear any non-radial load caused by internal shear and elongation stresses within the material being worked, during deformation, such non-radial loads being particularly high due to the low speed of operation in such roll stands; secondly, the guide way must bear the non-radial loads caused by the brutal operation of the roll stand and the high energy loss arising from the inertial forces of the to-and-fro movement of the material being rolled. Such a roll stand has a complex structure and is relatively expensive.

In a second known roll stand, two working rolls of small diameter are mounted on carriages so that they can be displaced relative to each other at right angles to the machine direction, i.e. the direction of travel of the material being rolled, the rolls being driven by frictional engagement (or by like arrangement) with eccentric segments which in turn are driven by means of racksand toothed sectors.

The spacing between the centres of rotation of the eccentric segments cannot be altered because this spacing is established by the toothed sector driving gear; thus the spacing between the axes of the Working rolls cannot be changed in this manner in order to take up wear or allow for changes in the section of the material being rolled. A further disadvantage is that a slideaway system is required for the carriages and the entire roll housing undergoes a reciprocatory motion in operation.

As a development of roll stands in which the axes of swing are themselves rotated about a further axis and which has the disadvantage that the direction of rolling is opposed to the direction of travel of the material being rolled, roll stands are known in which the working rolls are rotatably mounted in swinging supports which are driven by means of suitable mechanisms (for instance jointed or articulated linkages) with the working rolls having a small diameter and braced against bending by means of backing rolls also mounted in the swinging supports.

Roll stands of this latter type are not economical for all working loads; the greater the bending stress acting on the working rolls, the greater the size the backing rolls should have; however, the size of the backing rolls is lim- Patented Apr. 14, 1970 ited on the one hand by the distance of the working rolls from the axis of swing and on the other hand by the loss of power (which is proportional to the square of the radii of the backing rolls) caused by the inertial losses as the backing rolls reverse their direction of rotation twice during each swing of the swinging supports.

In addition, it is often necessary to replace the working rolls frequently due to the high frictional loading on the working rolls caused by the transmission of the forces to the backing rolls necessary to change the direction of rotation of the backing rolls.

According to the present invention, there is provided a roll stand for a rolling mill, having cooperating Working rolls rotatably mounted in swinging supports for guiding the working rolls along respective arcuate paths, and swinging backing segments mounted for swinging movement about the same axes as the respective swinging supports and'having arcuate section bearing faces against which the respective working rolls bear and roll along in operation, thereby to brace the working rolls against bending."

The roll stand of this invention can reduce the power loss in the mill and reduce the wear of the working rolls which is caused by inertial forces due to to-and-fro movement of the workpiece; in addition, the roll stand of this inventipn can be adjusted to allow for different sections of workpiece, and can be designed for any particular rolling load, the radius of the backing segments corresponding to the required resistance against bending stress; in this manner, the backing segments can have a minimum moment of inertia and can allow for a smaller roll stand housing. Furthermore, the roll stand of this invention can be arranged to be suitable for brutal operation.

The backing segments may be driven and a mechanical connection (i.e. friction or gear) provided to cause the working rolls to roll along the bearing surfaces of the backing segments and move along their arcuate working paths. This can reduce the frictional forces on the working rolls and avoid the necessity for driving the backing segments by means of the working rolls.

In order to prevent the working rolls from slipping on the backing segments or on the material being rolled, at least one gear Wheel may be fixed to each working roll so that it meshes both with an external gear segment fixed to the respective backing segment and with a stationary internal gear segment, the radius of the gear wheel pitch circle being the same as the radius of the working roll, and the radius of the external gear segment pitch circle being the same as the radius of the backing segment bearing surface.

The roll stand of the invention can be mounted in series with at least one other roll stand in a rolling mill in order to roll the material to its final size in one pass through the mill at a predetermined throughput speed; the material may for instance issue from a continuous casting plant. In order to balance or partly balance the inertial forces of the swinging supports, adjacent stands may be out of phase in the rolling cycle.

The. invention will be further described, by way of example, with reference to the accompanying drawings, in which:

FIGURE 1 is a vertical section through a roll stand in accordance with the invention, along the line I-I of FIGURE 2; and

FIGURE 2 is an elevation of a rolling mill in accordance with the invention, incorporating two roll stands generally as shown in FIGURE 1.

For convenience, the same references are used for the left-hand roll stand in FIGURE 2 as for the right-hand roll stand, but the references for the left-hand roll stand are primed. Though the section line for FIGURE 1 is 3 taken along the plane I-I of FIGURE 2, the references are not shown primed in FIGURE 1.

As shown in FIGURE 1, the two working rolls 1 are rotatably mounted in swinging supports 2 which are pivoted to spindles 3 mounted on a roll housing 4.

In addition, backing segments 5 are pivoted to the spindles 3 and are arranged to be driven in an oscillatory manner by reciprocating links 6, 7; the links 6, 7 may be driven by a crank drive (as shown in FIGURE 2) or by any other suitable manner, for instance an articulated drive system.

Gear wheels 8 are mounted at each end of each working roll 1 using suitable connection flanges, and these gear wheels 8 mesh both with an external gear segment 9 fixed to the respective backing segment 5 and with a stationary internal gear segment 9a, fixed to the roll stand. The pitch circles of the gear wheels 8 and of the gear segments 9 are arranged (in the manner indicated above) such that the working rolls 1 roll along the arcuate bearing surfaces of the backing segments 5, and are driven by the movement of the backing segments 5.

Though not shown, means (such as an eccentric mounting) may be provided for varying the spacing between the power of spindles 3.

In operation, the backing segments 5 are swung in unison, causing the working rolls 1 and the swinging supports 2 to swing at the same time. The material W is advanced into the roll gap when the swinging supports 2 have reached their outermost (i.e. upstream) dead centre position, the amount of advance of the material W depending on the smoothness of the material W and on the acceptable load during each stroke. The material W is held fast (for instance by the rolls 24, 25 shown in FIGURE 2) whilst the working rolls I carry out their rolling action.

The mill of FIGURE 2 has a driving system 10 including two contra-rotating gears 11 and spindles 12, 13. The cranks 14, 16 for the links 7', 6 are at an angle of 90 to the cranks 15, 17 for the links 7, 6 so that the two roll stands are 90 out of phase.

In operation, the material W is advanced by the pinch rolls 24, 25 when the working rolls 1 of the right-hand stand are in their outermost dead centre position. In the subsequent movement of the working parts, the working rolls 1 will move in the opposite direction to the working rolls 1' whilst the working rolls 1' smooth the surface of the material W.

The phase difierence between the roll stands makes the load on the driving system 10 more even. Furthermore, the spacing of the waves which are formed in the surface of the material W by the working rolls 1 of the right-hand stand is halved in the left-hand stand and the surface of the rolled material W is made more uniform.

The roll stand or mill of the invention may be used for rolling ferrous or non-ferrous metals.

Iclaim:

1. A roll stand for a rolling mill, having co-operating Working rolls rotatably mounted in swinging supports, for guiding the working rolls along respective arcuate paths, swinging backing segments mounted for swinging movement about the same axes as the respective swinging supports and having arcuate section bearing surfaces against which the respective working rolls bear and roll along in operation, thereby to brace the working rolls against bending, and means for driving the arcuate movement of the backing segments and the arcuate and rotary movements of the working rolls, the driving means including a mechanical driving connection between the working rolls and the backing segments to constrain the working rolls to roll along the bearing surfaces of the backing segments during the arcuate movement of the backing segments.

2. A rolling mill having in series at least two roll stands as claimed in claim 1, a driving mechanism, and mechanical transmissions connecting each stand to the driving mechanism with adjacent stands out of phase in the working cycle.

3. A rolling mill as claimed in claim 2, having only two said stands with the stands out of phase.

4. A roll stand as claimed in claim 1, comprising an external gear segment fixed to each respective backing segment, the radius of the external gear segment pitch circle being the same as the radius of the respective backing segment bearing surface, at least one gear wheel fixed to each working roll means and meshing with the respective external gear segment, the radius of the gear wheel pitch circle being the same as the radius of the respective working roll means, and a stationary internal gear segment meshing with each gear wheel.

References Cited UNITED STATES PATENTS 2,085,729 7/1937 Coe 72-214 2,125,686 8/1938 Norton 72-215 3,103,139 9/ 1963 Saxl 72215 FOREIGN PATENTS 48,131 10/1937 France.

LOWELL A. LARSON, Primary Examiner US. Cl. X.R. 72241

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