US3648342A

US3648342A - Movable combination of rolls

Info

Publication number: US3648342A
Application number: US12355A
Authority: US
Inventors: Gerhard Walter Dorfel
Original assignee: Ahlstrom Corp
Current assignee: Lenox Machine Co Inc
Priority date: 1969-04-29
Filing date: 1970-02-18
Publication date: 1972-03-14
Anticipated expiration: 1989-03-14
Also published as: CA922333A; FI45589C; FI45589B

Abstract

A beam provides a support for a series of rolls journaled side by side between bearing brackets. The bearing brackets are forked and movable vertically in relation to the beam. The relative movement of the brackets is controlled by, e.g., pressure bellows, diaphragm cylinders, pneumatic or hydraulic cylinders and the like. The rolls are journaled between the bearing brackets in pivot bearings mounted in the furcations of the bearings. Between these furcations there has been journaled a smaller diameter intermediate roll to establish a substantially continuous line of contact together with the rolls. By the aid of the control elements disposed between the beam and the brackets the shape of the contact line is changed as desired. The combination of rolls may be used as a loading roll for a roll of a material web which is to be wound up, for the purpose of achieving uniform lineal pressure over the entire width of the roll. The combination may also be utilized as a support roll for a moving web, wire or felt to equalize differences in tension occuring in the direction across the wire, felt or material web.

Description

Unite Muriel 1 ar. M, W72

[54] MOVABLE COMBINATION OF ROLLS Primary Examiner-Alfred R. Guest [72] Inventor' gag? Walter Dorm Rlmulanmak" Attorney-Ralph E. Bucknam, Jesse D. Reingold, Robert R.

Strack and Henry A. Marzullo, Jr. [73] Assignee: A. Ahlstrom Osakeyhtio, Noormarkku,

Finland [57] ABSTRACT [22] Filed:. Feb. 18, 1970 A beam provides a support for a series of rolls journaled side by side between bearing brackets. The bearing brackets are [21] Appl' 112555 forked and movable vertically in relation to the beam. The

relative movement of the brackets is controlled by, e.g., pres- [30] Foreign Application Priority Data sure bellows, diaphragm cylinders, pneumatic or hydraulic cylinders and the like. The rolls are journaled between the Apr. 29, 1969 Finland ..1258 bearing brackets in Pivot bearings mounted in the furcations of the bearings. Between these furcations there has been jour- 8| naled a smaller diameter intermediate m" to establish a [58] Fie'ld 242/66 65 stantially continuous line of contact together with the rolls. By 542/55 the aid of the control elements disposed between the beam and the brackets the shape of the contact line is changed as [56] References Cited deslred- The combination of rolls may be used as a loading roll for a UNITED STATES PATENTS roll of a material web which is to be wound up, for the purpose 3,301,498 1/1967 Greding ..242/66 of achieving uniform lineal pressure over the entire width of 3,308,519 3/1967 Westgate the roll.

gir 242/66 The combination may also be utilized as a support roll for a moving web, wire or felt to equalize diflierences in tension oc- FOREIGN PATENTS OR APPLICATIONS curing in the direction across the wire, felt or material web.

822,592 1 l/l951 Germany ..29/ 125 10 Claims, 9 Drawing Figures SHEET 1 BF 5 PATENIEDMAR m 1912 SHEET 3 OF 5 PATENIEBMAR 1 4 I972 SHEET 0F 5 PAIENTEBHARMISTZ 3,648,342

sum 5 (1F 5 MOVABLE COMBINATION or sous BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a movable system of rolls joumalled at a distance from each other on a support, and particularly to loading and tension equalizing systems for material webs, wires and felts.

2. Description of the Prior Art In multiple calendar machines (U.-S. Pat. No. 3,203,552) the lineal pressure between rolls placed one above the other has been controlled by providing upon the uppermost roll a loading mechanism which comprises a plurality of rolls carried in supporting arms axially one beside the other at equal distance and the loading pressure exerted by which on the top roll can be individually adjusted by means of a pressure medium-operated control device acting upon the pair of supporting arms of each loading roll. This implies that the rolls need not have any bulged shape, while it is possible all the same to achieve a straight press nip. In addition, it has been possible to large because the supporting arms placed on either side of each loading roll require much space. Therefore, it has not been possible with the aid of the loading rolls to establish any continuous contact with the top roll. But this is no serious drawback in multiple calender machines, in which the pressure from the loading rolls acts on the material web only indirectly, often over an interposed roll, whereby the pressure produced by the loading rolls is continuously distributed across the web.

But this loading mechanism known in the prior art, which has been used in multiple calender machines, cannot be ap plied, e.g., as a loading roll for a winding-on roll, where the loading rolls would act immediately on the material web without any interposed rolls. This is because extensive unloaded stretches remain between the loading rolls, which would decisively affect the result of the winding process.

SUMMARY OF THE INVENTION The improved combination of rolls according to the invention comprises bearings at the ends of the rolls by which the rolls are joumalled between the opposite furcations of the adjacent bearing brackets and a smaller diameter intennediate roll joumalled between the adjacent rolls in the prong of each bearing bracket.

The movable combination of rolls according to the invention can be applied immediately against the web without interposed equalizing rolls, e.g., for the purpose of:

a. exerting equal lineal pressure over the entire axial length of rotating cylindrical bodies, such as paper rolls,

b. automatically eliminating differences in tension which may occur in moving webs,

c. measuring in the course of manufacturing, differences in diameter of rolls and differences in elasticity occurring in moving webs, and

d. measuring stresses occurring in moving webs and lineal pressures acting on them.

When paper, fabric, plastic or thin metal sheet webs are wound up into rolls upon so-called supporting rolls, consistent lineal pressure between the roll and the supporting rolls possesses decisive importance in view of unifonn winding stress in the axial direction of the roll. Requisite uniformity of lineal pressure is achievable when a movable combination of rolls according to the invention is used as a loading mechanism.

When manufacturing and handling paper, fabric and plastic webs, a movable combination of rolls according to the invention can be applied to equalize the differences in tension occurring in the web which result from unavoidable differences in the elastic properties of the web. At the same time partial overstressing of the web is prevented.

A combination of rolls according to the invention may also advantageously be used for equalizing the tension in endless moving screen or membrane webs, e.g.,. as tension roller for a wire or felt in a paper machine.

When a combination of rolls according to the invention is used as loading roll or as tension equalizing roll, it is possible to gain an indication of the differences in roll diameter or in web tension by measuring the displacements of the journalling brackets. When such a combination of rolls is applied as web tension equalizing roll, the tension of the web can be measured, and when it is applied as loading roll, the lineal pressure can be measured across the entire web. The measured values may then be employed in controlling the web tension or lineal pressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 presents a transversal view of a combination of rolls according to the invention,

FIG. 2 is the section along the line 8-8 in FIG. I and shows a cross-sectional vertical partial view of an advantageous embodiment of the invention,

FIG. 3 is taken along the line A-A of FIG. 2,

FIG. 4 is the section along the line C--C in FIG. 2,

FIG. 5 presents a similar partial view as that in FIG. 2 of another alternative embodiment,

FIG. 6 shows a vertical axially sectioned partial view of an additional embodiment according to the invention,

FIG. 7 shows the same device as FIG. 6 but from another point and only partly in section, and

FIGS. 8 and 9 finally show two different embodiments from the side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The combination of rolls shown in FIG. 1 comprises a highly rigid horizontal beam or girder I, under which there are several comparatively short rolls 2, placed axially and at equal distances from each other. Adjacent rolls 2 have been journalled in-the bearing brackets 4 on both sides, that is each roll is carried at both ends in one bearing bracket each. Between each two rolls 2 and also beside the outer ends of the outermost rolls 2 there have furthermore been fitted intermediate rolls 3 of smaller diameter, which have been joumalled in the prongs of the bearing brackets 4 so that the

rolls

2 and 3 form a substantially continuous point of contact, which is a straight line when the combination is uniformly supported, as in FIG. 1. The prongs of brackets 4 form a socket for the rolls.

Between the bearing brackets 4 and the girder I there have been fitted

pressure bellows

7, 9, which have been mutually connected by means of a line 8 to which furthermore has been connected a pressure gauge 13, as has been schematically indicated in FIG. 1.

In FIGS. 2, 3 and 4 it has been shown in greater detail how the

rolls

2 and 3 are carried in the bearing brackets 4 and how these in their turn have been fitted to connect'with the girder I. It is seen that the rolls have been fitted axially on both sides of the bearing bracket 4 in pivot bearings 14, which have been mounted on cylindrical projections on either side of the bearing bracket 4. Therefore the rolls 2 are freely rotatable and angularly turnable at their ends so that their imaginary axes can freely assume various angular positions with reference to each other. Between the prongs of the bearing bracket 4 a freely rotatable intermediate roll 3 has been joumalled, which is smaller in diameter than the rolls 2 and the axial length of which is only little less than the distance between the rolls 2. The

rolls

2 and 3 thus form a substantially continuous contact point, but which is changeable of its shape, with the web or equivalent (not shown) which is placed against them.

Both edges of the mantle of the rolls 2 have furthermore been rounded with the radius R (FIG. 3) so that no sharp transition is formed between the

rolls

2 and 3 which might cause marginal stresses, even if the imaginary axis of the roll 2 is in inclined position with reference to the axis of the roll 3.

To the front and rear of the bearing bracket 4 vertical flanges have been fixed which have been fitted to slide between guide plates 5 attached to the girder 1. One of the two flanges has a guide rail, which has been fitted to guide the bracket 4 with the aid of a groove provided in the adjacent guide plate 5, as can be seen from FIG. 4. To the lower edges of the guide plates 5, furthermore, stops 6 have been fixed which limit the downward travel of the bearing bracket 4.

Between the flanges of the bearing bracket 4, between the bearing bracket and the girder 1, there have been placed pressure bellows 7, which have been connected to a common, closed pressure system consisting of the pipe 8. The

bellows

7, 9 and pipe 8 have been filled with some appropriate pressure medium, such as air or some conventional hydraulic fluid. Both outermost pressure bellows 9 have a functional area smaller by one half than the intermediate pressure bellows 7, because the first-mentioned bellows only act upon one roll 2 each. Accordingly, the relation between pressure and force is equal in all bellows 7, 9. The line 8 is moreover connected to a pressure gauge 13, by means of which the force acting on the combination of rolls is measurable.

Thanks to the closed pressure system, automatic equalization of the pressure in the entire combination of rolls is achieved. If one of the brackets 4 rises upwardly, the pressure in its bellows 7 increases when this is compressed, and pressure medium will flow from the bellows 7 into the line 8, from which it is uniformly distributed into the

other bellows

7, 9, each of which forces its respective bracket downward by a greater or smaller amount of travel. It follows that part of the stress placed on the bracket 4 is uniformly distributed among the other parts of the combination of rolls and no overloading may ensue. The gauge 13 also always indicates the true load acting on the

rolls

2, 3.

In FIG. 5 another embodiment of the bearing bracket involving lesser freedom of travel has been presented. In this instance the bearing bracket is a lever arm 4' which has been pivoted to be tumable about the axis 15 on one outer side of the girder 1. The

rolls

2 and 3 have been joumalled in the manner described above in one end of the lever arm 4', the travel of which has been restricted by means of a stop 6 fixed immediately to the girder. Between the girder 1 and the said end of the lever arm 4' there has also been fitted a pressure bellows 7, by the aid of which the angular travel of the lever arm 4 is controllable. The position of the lever arm 4' is indicated by means of a measuring instrument 12, which is in contact with the other, shorter arm of the lever 4'. On the basis of the result of measurement of the instrument 12, the pressure in the bellows 7 may be either increased or decreased in order to change the position of the lever arm 4.

It is also possible to use electrical or electronic pressure gauges instead of pressure bellows, whereby'force equalization in the longitudinal direction of the combination of rolls is accomplished with the aid of a control valve, which on the basis of the mean from all points of measurement is governed by the true force value. This embodiment is comparatively expensive, however.

The

rolls

2 and 3 may also be provided with a resilient coating if desired.

The embodiment presented in FIG. 6 differs from that shown in FIG. 3 in that the rolls 2 have been connected with each other by means of a shaft 19 of adjustable length, which has at both ends universal joints 17, which connect this shaft 19 to the shafts of both rolls 2, which have been carried in swivel bearings in the prongs of the bearing bracket 4. The intermediate roll 3 carried between the prongs of the bearing bracket 4 below the shaft 19 is even now freely rotatable, whereas the rolls 2 rotate at identical speed and are advantageously positively driven, as can be seen from FIG. 7.

In FIG. 7, the rightmost roll 2 has been connected to an external power transmission comprising pulleys 15 driven by a motor 18, the lower of these pulleys being joumalled in the girder 1 and driving a shaft provided with universal joints 17 at both ends and the inner end of which is connected with the said roll 2. The said shaft passes through a bore 20 in the hearing bracket 4.

Instead of using a shaft of adjustable length, it is possible to connect the shafts of the rolls 2, which then have been lengthened, immediately with each other by means of a universal joint. The intermediate rolls need not necessarily be freely tumable, instead of which they may be made positively driven and may be driven at the same speed as the rolls 2. It is also possible to make the rolls 2 freely rotatable and the intermediate rolls positively driven, if desired.

In the embodiment illustrated by FIG. 8, a combination of rolls according to the invention has been arranged to constitute the loading roll 16 for a roll 11 placed upon two supporting rolls. When the problem is to wind a web 10 of nonunifon'n thickness into a roll 1 1 having uniform hardness in the transversal direction, the roll 11 will have somewhat greater diameter at the points where the web is thicker than at its thinner points. A nonnal roll used in conventional manner as a loading roll would then'only rest on those points where the diameter is largest, and the roll would obviously be nonuniform in hardness. This is prevented by means of a combination of rolls according to the invention and uniform lineal pressure is achieved over the entire width of the roll 11. With the aid of the closed pressure system, pressure equalization is accomplished in the pressure bellows 7, 9, whereby pressure medium is pressed from the bellows located opposite areas of large diameter into those which coincide with areas presenting a smaller diameter. The differences in diameter can be indicated by means of the measuring instrument 12 (FIG. 5), and the lineal pressure can be indicated by means of the pressure gauge 13 (FIG. 1). The desired lineal pressure may be adjusted and controlled by relieving or loading the girder 1.

It is important, when manufacturing and handling elastic material webs, that a given web tension is accomplished across the web so that the web can be unwound and subjected to further handling under best possible conditions, and formation of folds in the manufacturing process itself is prevented. At the manufacturing of paper, fabric and plastic webs, it is not possible to achieve equal elastic properties all over the surface of the web. During manufacturing and handling, the webs have been maintained under reasonable tension by the aid of pairs of traction rolls or of the winding-on shafts. It is obvious, however, that less elastic parts of the web are then subjected to greater stress than other portions of the web. In many instances this has been the cause of ruptures and of inferior quality.

When a combination of rolls according to the invention is applied, in its embodiment shown in FIG. 9 the above-mentioned drawbacks may be completely eliminated.

In FIG. 9, the girder 1 has been immovably arranged in horizontal position and in a vertical plane, and the material web 10 is passed over the combination of rolls 20 with small lapping angle, symmetrically with reference to the contact point between the

rolls

2 and 3 and the web. This arrangement eliminates the differences in tension in the web 10 by means of the pressure equalization between the

bellows

7, 9, in that the less elastic parts of the web will have to travel a shorter distance for the reason that the rolls opposite to such portions descend to a lever lower than that of the other rolls. The pressure prevailing in the

bellows

7, 9 and in the line 8 is directly proportional to the tension of the web and it may be conducted over a pressure transducer 13, as the true pressure value, to eflect after-adjustment of the web tension. The rolls 3 are advantageously made as large as possible in diameter, compared to the rolls 2, and the mass of the

rolls

2 and 3 is made as small as possible.

The embodiment shown in FIG. 9 may also advantageously be applied to produce tension in the wire of felt of a paper machine.

The closed pressure system may be formed in simple manner of tubing of sufficiently large diameter and which is closed at its ends, which is fitted axially between each bearing bracket and the girder.

A combination of rolls according to the invention may equally be used in multiple calender machines, in presses, in bumishing appratus and equivalent, in which the combination of rolls acts indirectly upon the web by mediation on one or several interposed working rolls. The control elements, e.g., the pressure pipes, may also be made individually controllable, whereby the point of contact constituted by the rolls may be adjusted to have desired shape, independent of the load.

Iclaim:

l. A roll assembly providing a substantially uninterrupted line of work contact comprising a transverse beam, a plurality of bearing units mounted on the beam, a pressure control member mounted upon each of said bearing units, means for connecting said pressure control members to the bearing units, a plurality of first rolls pivotally mounted between the bearing units, joumalled at a predetermined distance one from the other to the bearing units, said rolls being vertically displaceable in relation to the beam, a plurality of second intermediate rolls of smaller diameter pivotally mounted on said bearing units between adjacent pairs of said first rolls, the axis of said second rolls being offset from the axis of said first rolls whereby a single substantially continuous line of contact with a workpiece is established across the faces of said first and said second rolls.

2. The roll assembly according to claim 11 wherein the pressure control members are bellows and the means for connecting the bellows are pipes filled with a hydraulic fluid.

3. The roll assembly according to claim 2 wherein the bearing units are cup shaped and form sockets to which are mounted said bellows.

ll. The roll assembly according to claim 1 wherein the bearing units are lever arms to which are joumalled said first and second rolls.

5. The assembly according to claim 1, wherein the said first rolls have shafts and the shaft of adjacent rolls are mutually connected with a universal joint in order to rotate the rolls at the same speed.

6. The assembly according to claim 1 wherein the shafts of adjacent rolls are mutually connected by a shaft of adjustable length, both ends of which are connected by a universal joint to the respective roll for the purpose of rotating the rolls at the same speed.

7. The assembly according to claim 1 wherein at least one terminal roll is connected to an external drive unit for driving the rolls.

8. The combination according to claim 1, wherein the outermost pressure control members have an operative area onehalf that of the intermediate control members.

9. The assembly according to claim 1, in which the second rolls have rounded mantle edges in order to provide a curved transition between each of the second rolls and the adjacent first roll when the axes of these rolls from an angle with each other.

it). In an apparatus for winding a web into a roll having uniform hardness in the transversal direction, which roll is rotatably joumalled in a frame for movement about a horizontal stationary axis, an improved loading mechanism comprismg:

a traverse beam extending across the frame above the roll and vertically movable in relation thereto;

a plurality of loading rolls on the beam joumalled at a distance one of the other;

forked bearing brackets supporting the loading rolls therebetween and vertically movable in relation to the beam;

bearing units at the ends of the loading rolls for supporting the loading rolls between the bearing brackets;

smaller diameter intermediate rolls joumalled between the loading rolls, in the prongs of each forked bearing bracket for establishing a substantially uninterrupted line in cooperation with the loading rolls; and

communicating fluid pressure means; disposed between the beam and each bearing bracket for the purpose of achieving uniform lineal pressure over the entire width of the

Claims

1. A roll assembly providing a substantially uninterrupted line of work contact comprising a transverse beam, a plurality of bearing units mounted on the beam, a pressure control member mounted upon each of said bearing units, means for connecting said pressure control members to the bearing units, a plurality of first rolls pivotally mounted between the bearing units, journalled at a predetermined distance one from the other to the bearing units, said rolls being vertically displaceable in relation to the beam, a plurality of second intermediate rolls of smaller diameter pivotally mounted on said bearing units between adjacent pairs of said first rolls, the axis of said second rolls being offset from the axis of said first rolls whereby a single substantially continuous line of contact with a workpiece is established across the faces of said first and said second rolls.

2. The roll assembly according to claim 1 wherein the pressure control members are bellows and the means for connecting the bellows are pipes filled with a hydraulic fluid.

4. The roll assembly according to claim 1 wherein the bearing units are lever arms to which are journalled said fiRst and second rolls.

6. The assembly according to claim 1, wherein the shafts of adjacent rolls are mutually connected by a shaft of adjustable length, both ends of which are connected by a universal joint to the respective roll for the purpose of rotating the rolls at the same speed.

7. The assembly according to claim 1, wherein at least one terminal roll is connected to an external drive unit for driving the rolls.

8. The combination according to claim 1, wherein the outermost pressure control members have an operative area one-half that of the intermediate control members.

10. In an apparatus for winding a web into a roll having uniform hardness in the transversal direction, which roll is rotatably journalled in a frame for movement about a horizontal stationary axis, an improved loading mechanism comprising: a traverse beam extending across the frame above the roll and vertically movable in relation thereto; a plurality of loading rolls on the beam journalled at a distance one of the other; forked bearing brackets supporting the loading rolls therebetween and vertically movable in relation to the beam; bearing units at the ends of the loading rolls for supporting the loading rolls between the bearing brackets; smaller diameter intermediate rolls journalled between the loading rolls, in the prongs of each forked bearing bracket for establishing a substantially uninterrupted contact line in cooperation with the loading rolls; and communicating fluid pressure means disposed between the beam and each bearing bracket for the purpose of achieving uniform lineal pressure over the entire width of the roll.