US3750448A

US3750448A - Twin stand rolling mill-azial roll alignment

Info

Publication number: US3750448A
Application number: US00125678A
Authority: US
Inventors: R Oxlade
Original assignee: British Iron and Steel Research Association BISRA
Current assignee: British Iron and Steel Research Association BISRA
Priority date: 1970-03-18
Filing date: 1971-03-18
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07
Also published as: ZA711436B; DE2112998A1; SE382398B; CA951549A; BE764414A; FR2083396B1; GB1333065A; FR2083396A1

Abstract

A four-high rolling mill stand has each work roll mounted to the free end of a preloaded drive shaft rotatably carried in an individual arm pivotally mounted in the mill frame. The effective position of the pivot axis of one arm is movable through a limited arc relative to the pivot axis of the other arm by means of limited rotation of eccentric pivot pins, whereby to effect adjustment of the axial position of the work rolls relative to one another to avoid ovality or assymetry in the rolled stock.

Description

United States Patent [191 [111 3,750,448

Oxlade 1 Aug. 7, 1973 [54] TWIN STAND ROLLING MILL-AZIAL ROLL 3,613,428 10/1971 Townsend et a1 72/237 ALIGNMENT 3,468,151 9/1969 Diolot 72 245 x W s M. 3,190,098 6/1965 Wilson 72/223 [75 Inventor: Roy R. Oxlade, London S. W. 8, 1,822,697 9/1931 Hahnemann 72/247 England Assignee: The British Iron and Steel Research Association, London, England Primary Examiner-Milton S. Mehr Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A four-high rolling mill stand has each work roll mounted to the free end of a preloaded drive shaft r0- tatably carried in an individual arm pivotally mounted in the mill frame. The effective position of the pivot axis of one arm is movable through a limited arc relative to the pivot axis of the other arm by means of limited rotation of eccentric pivot pins, whereby to effect adjustment of the axial position of the work rolls relative to one another to avoid ovality or assymetry in the rolled stock.

9 Claims, 3 Drawing Figures PATENTEDAuc 7 I975 sum 1 or 3 INVENTOR ATTORNEY PAIENIEL 71975 3.750.448

sum 2 or 3 FIG.2.

lNVENTOR BIY ATTORNEY.

PATENTEL 7 I975 SHEEI 3 OF 3 @V/ZV/Z INVENTOR ATTORNEY TWIN STAND ROLLING MILL-AZIAL ROLL ALIGNMENT BACKGROUND OF THE INVENTION This invention relates to rolling mills and particularly, but not exclusively, to rod or bar stock rolling mills.

US. Pat. No. 3,613,428, discloses a rolling mill stand including a frame, two work rolls drivably carried in said frame, an arm rotatably carrying one of said work rolls, means pivotally mounting said arm in said frame, said means defining a pivot axis extending substantially parallel to and spaced apart from the stock pass line between said work rolls, said pivot axis being substantially fixed in position relative to said arm, whereby said arm carrying its associated work roll is pivotally movable about said fixed pivot axis to permit adjustment of the work gap between said rolls, and wherein said work rolls are backed up by support rolls rotatably mounted in said frame so that the axes of rotation of the support rolls are movable with respect to the frame for alignment of the support rolls on their associated work rolls. Preferably, each said work roll is carried in an individual arm pivotally mounted in said frame, both arms being pivoted about a substantially common pivot axis.

US. Pat. No. 3,587,267, discloses, in one aspect thereof, a rolling mill stand wherein at least one of the work rolls is carried on a shaft mounted to be movable to a limited extent at least about a specified axis, and preferably about a point, so that the work roll can move slightly in the stock pass line. A load cell is provided between the work roll shaft and the mill frame to provide a signal indicative of the stock tension. The shaft is preferably mounted in a bearing block which is slidable in a guide to a limited extent axially of the shaft. Hydraulic capsules are defined between the block and the guide and means are provided for controllably supplying fluid under pressure to said capsules, whereby the axial position of the shaft is controllably adjustable. The main reason for this adjustment is to permit accurate alignment of the roll grooves in the work rolls to avoid ovality or assymmetry in the rolled stock. The pressure in the capsules also determines the preloading of the shaft bearing assembly as a whole.

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved arrangement for permitting alignment of the roll grooves with respect to one another.

According to the present invention there is provided a rolling mill stand comprising a frame, two work rolls drivably carried in said frame, an arm rotatably carrying one of said work rolls, said arm being pivotally mounted in said frame, said work rolls being backed up by support rolls rotatably carried in said frame and wherein means is provided for adjusting the effective position of the pivot axis of said pivotal mounting whereby to permit adjustment of the axial position of the work rolls with respect to one another.

BRIEF DESCRIPTION OF THE DRAWINGS An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a side view of a fOUFhIgl'I rolling mill stand according to the invention with a vertical part of the mill frame removed for clarity;

FIG. 2 is a sectional view taken substantially along line A--A of FIG. 1, and

FIG. 3 is a sectional view taken substantially along line 8-8 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings there is shown a four-high rolling mill stand comprising a frame having

vertical side members

10, 11 and upper and lower cross members l2, 13. Two arms l4, 15 are pivotally mounted in the frame. The upper arm 14 has a pivot axis 16 and the lower arm a pivot axis 17. The arms rotatably mount work

roll drive shafts

18, 19 respectively having work rolls 20, 21 mounted to the free ends thereof. The shafts are driven by motors (not shown) through

couplings

22, 23, preferably both of which allow limited axial movement of their respective shafts.

Support rolls

24, 25 back up the work rolls and are mounted in the frame so that their axes of rotation are movable for alignment of the support rolls on their respective work rolls. In this embodiment the support rolls are carried by the respective arms l4, 15.

The lower arm 15 is pivotally mounted to the frame by means of pivot pins 30 which are symmetrical about pivot axis 17 and which work in bores 31 formed in the heads 32 of eccentric pivot pins 33. Heads 32 are normally fixedly secured with respect to the lower arm 15. The heads 32 have an outer cylindrical surface 34 coaxial with the axis 17 of pin 30. The heads 32 are received in split housings forming part of the lower arm 15. An upper semi-circular part 40 of each housing is secured to arm 15 by two bolts 41. The dimensions are such that when bolts 41 are tightened the housing grips or locks the associated pivot pin head 32 to prevent rotation thereof. When the bolts 41 are slackened the heads 32 may be rotated relative to the arm 15.

Pivot pin 33 has a circular cross section tail portion 45 eccentric with respect to its head 32. This is best shown in FIG. 3. The upper arm 14 is mounted for rotation on the tail portion about the tail portion axis 16 by means of a suitable bearing assembly, such as a preloaded taper roller bearing assembly 46.

It will now be appreciated that if the eccentric pivot pin 33 were to be rotated about the axis 17 of pivot pin 30, then the axis 16 of the tail portion 45 will describe a small circle about pivot axis 17. Since only a small amount of relative movement of the

pivot axes

16 and 17 is required, and that amount is required generally only in the axial direction of the work roll shafts l8, 19, the eccentric pivot pin 33 is arranged only to be rotated through a limited arc to both sides of a lower dead center position as shown in FIGS. 2 and 3. An arc of up to about 45 each said of the center position would normally be sufficient.

The pin 33 may be so rotated by any suitable means, but the arrangement particularly shown comprises toothed segments 50 secured to the respective pins 33. The segments are driven by gears 51 mounted on a shaft 52 which in turn is driven by a suitable motor (not shown). The extent of movement of segments 50 is preferably indicated by a scale visible to the mill operator. As an alternative to segments 50, bell crank levers may be employed, and instead of a drive motor, hydraulic cylinder power or manual operation may be used. As noted above, bolts 41 should be slackened before the above adjustment is effected, and retightened after adjustment. It will be appreciated that the adjustment described comprises movement of the whole upper arm 14 relative to the lower arm, in either direction generally axially of the work roll shafts. Consequently precise alignment of the roll grooves in the work rolls can be effected.

Details of other features of the mill stand will be found in U. S. Pat. Nos. 3,611,53l, 3,587,267, 3,613,428 and pending US. Application Ser. No. 881,801, filed December 3, 1969 each of which is assigned to the assignee of the present invention.

An advantage of the above described arrangement for adjusting alignment of the roll grooves is that the upper arm 14 is moved as a whole, including its associated work roll drive shaft. Thus the bearings of the drive shaft and their preloading remain undisturbed by the adjustment. In more detail, the drive shaft 18 is rotatably mounted in a rear bearing assembly 60 which preloads the shaft both radially and axially and also permits universal pivotal movement of the shaft to a very limited extent in any direction about point 61. The reason for this is discussed more fully in the above noted U.S. patents and pending U.S. patent application.

The bearing assembly 60 comprises a central selfaligning spherical roller bearing 62 with a pair of oppositely directed spherical

roller thrust bearings

63, 64 spaced on opposite sides thereof by

spacer rings

65, 66. The whole bearing assembly is axially preloaded by hydraulic fluid introduced under pressure to capsule 70 to urge'sliding block 71 axially against bearing 63. The more remote face of opposite bearing 64 is consequently urged against a positive end stop constituted by a part 72 of the bearing housing. This arrangement pro vides a somewhat stiffer system in the axial direction than an earlier arrangement wherein balanced hydraulic pressure cap chambers were utilized both to preload the shaft and to adjust its position axially.

I claim:

1. A rolling mill stand comprising a frame, two work rolls drivably carried in said frame, an arm rotatably carrying one of said work rolls, pivot means pivotally mounting said arm in said frame, said pivot means defining for said arm a movable pivot axis extending parallel to and spaced apart from the stock pass line between said work rolls, said work rolls being backed up by support rolls rotatably carried in said frame, means being providedfor adjusting the effective position of the movable pivot axis defined by said pivot means in a direction transverse to said pivot axis position to permit adjustment of the axial position of the work rolls with respect to one another.

2. A rolling mill stand according to claim 1 wherein each said work roll is carried in an individual arm pivotally mounted in said frame.

3. A rolling mill stand according to claim 2 wherein the effective position of said movable pivot axis of said first mentioned arm is adjustable in an are centered on the pivot axis of the other arm.

4. A rolling mill stand according to claim 1 wherein said means for adjusting the effective pivot axis position comprises means for rotation through an arc, and in unison, a pair of eccentric pivot pins, said pivot pins being associated with and serving pivotally to mount said first mentioned arm.

5. A rolling mill stand according to claim 4 wherein the eccentric pivot pins are each rotatable through a limited arc to both sides of a lower dead center position.

6. A rolling mill stand according to claim 4 including releasable means for releasably clamping each pivot pin to prevent rotation thereof when adjustment movement is not required.

7. A rolling mill stand according to claim 1 wherein said work rolls and their associated support rolls have substantilly cylindrical outer surfaces for mutual engagement.

8. A rolling mill stand according to claim 1 wherein said movable pivotal axis intersects the axis of rotation of the work roll carried by said pivotally mounted arm.

9. A rolling mill stand according to claim 1 wherein said first mentioned arm carries its associated work roll mounted to a free end of a work roll drive shaft, said shaft being rotatably mounted in said arm in bearings arranged to preload the shaft both radially and axially. It i II F UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 7 ,448 Dated August '7, 1973 Inventor-(s) R Y OXLADE v It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the Heading:

Delete the present title reading "TWIN STAND ROLLING MILL-AZIAL ROLL ALIGNMENT", and insert --TWIN STAND'R'OLLING MILL-AXIAL ROLL ALIGNMENT-- Signed and sealed this 25th day of December 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMIEYER Attesting Officer Acting Commissioner of Patents F ORM PO-105O (10-69) I USCOMM-DC 6O376-P69 u.s. GOVERNMENT PRINTING OFFICE Isis oass-3u.

Claims

1. A rolling mill stand comprising a frame, two work rolls drivably carried in said frame, an arm rotatably carrying one of said work rolls, pivot means pivotally mounting said arm in said frame, said pivot means defining for said arm a movable pivot axis extending parallel to and spaced apart from the stock pass line between said work rolls, said work rolls being backed up by support rolls rotatably carried in said frame, means being provided for adjusting the effective position of the movable pivot axis defined by said pivot means in a direction transverse to said pivot axis position to permit adjustment of the axial position of the work rolls with respect to one another.

3. A rolling mill stand according to claim 2 wherein the effective position of said movable pivot axis of said first mentioned arm is adjustable in an arc centered on the pivot axis of the other arm.

4. A rolling mill stand according to claim 1 wherein said means for adjusting the effective pivot axis poosition comprises means for rotation through an arc, and in unison, a pair of eccentric pivot pins, said pivot pins being associated with and serving pivotally to mount said first mentioned arm.

9. A rolling mill stand according to claim 1 wherein said first mentioned arm carries its associated work roll mounted to a free end of a work roll drive shaft, said shaft being rotatably mounted in said arm in bearings arranged to preload the shaft both radially and axially.