US3103875A

US3103875A - Roll deflection

Info

Publication number: US3103875A
Application number: US94261A
Authority: US
Inventors: Lawrence A Moore
Original assignee: Beloit Iron Works Inc
Current assignee: Beloit Iron Works Inc
Priority date: 1961-03-08
Filing date: 1961-03-08
Publication date: 1963-09-17
Anticipated expiration: 1980-09-17
Also published as: GB940938A

Description

Sept. 17, 1963 L. A. MOORE 3,103,875

ROLL DEFLECTION Filed March s. 1961 26: INVENToR i s 26@ Lawrence /hgasus Muore S BY 2@ zwmww; :zw

A TTO NE YS United States Patent Oh ice Patented Sept. i7, 1663 3,163,375 RUM., DEFLECTIN Lawrence A. Moore, Beloit, Wis., assigner to Beloit Iron Works, Beloit, Wis., a corporation of Wisconn Filed Mar. 8, 1%1, Ser. No. 94,261 8 Claims. (Ci. HPO-155) This invention relates to apparatus for mounting a roll whose axis is subject to deection, and more particularly, -to an apparatus for mounting a roll that is subjected to a load tending to effect central deflection of the roll axis.

Although the instant invention may be useful in a number of arts, it is lparticularly useful in the paper making art and will be described primarily in connection therewith. In paper machines, there are a number of different types of rolls of substantial size (i.e., substantial length-to-diameter ratios) which are subjected to loads tendinf7 to deiiect such rolls centrally. For example, wire return rolls in a Fourdrinier paper machine are subject to a load tending to effect central deliection thereof by virtue of the weight of the rolls themselves and of the Fourdrinier wire carried by the rolls, the tension on the `Fourdriner wire, and, in the case of a driven roll, the force component resulting from the resistance or reaction of the wi-re itself to the idriving fonce. hese forces tend to deiiect the roll downwardly in the middle and this results in an undesirable `guidance of the traveling wire, which it has been `found advantageous to avoid by counteracting the tendency for downward deilection of the return roll in one manner or another.

In addition, in press couples, calender stacks, etc. the web passes through a nip between a pair of superimposed rolls whereat the web is subjected to pressures. The pressures thus applied at such nip tend to load the lower roll 1and 4deliect the same centrally downwardly. Such deection results in 'an undesirable application of forces across the nip and other undesirable operating features; and such deflection is often corrected in paper machines yby crowning of the lower roll. The crowning of the roll requires accurate and expensive iinishing of the roll surface so `as to obtain a slightly greater roll diameter in the central portion of the roll; but such crowning is carried out on the basis of a predetermined set of force conditions and may not be satisfactory for operation `under la diiferent set of force conditions. Accordingly, crowning of rolls often does not alford satisfactory operation for many different types of operating conditions.

In other -arts relating to paper machines, such as the coating of paper or lfabrics with plastic materials, pressure or calender rolls are also used. Also, paint mixing roll systems or the like are subject to the Ibuildup of forces in the centra-l portion of pressure nips which tend to cause cent-ral deiiection yof the rolls and result in nonuniform and/or other undesirable conditions across the width of such press nips.

The instant invention affords a simple lbut unique mounting arrangement for a roll subject to a load tending to cause deflection of its axis. One aspect of the instant invention involves the use of force couples applied through allochir-al pairs of ybearings mounting a roll, ie., a right y hand pair land a left hand pair of bearings rotatably receiving ystub shaft elements at `opposite ends of the roll (or looking in the machine direction, at opposite sides of the roll). These pairs of bearings are referred to herein ias allochiral for the reason that they are opposed right and left hand `assemblies although not entirely symmetrical in every detail. The use of a pair of bearings to rotatably receive a shaft at one end of a roll for, the purpose of applying 4a. force couple thereto, wherein one of the bearings is fixed and the other movable, is shown in the prior art, for example, in Goulding U.S. Patent No. 2,611,150.

In the instant invention, however, lboth of each pair of bearings in the assembly used to .apply a given force couple to the shaft are bearings lfixed with respect to each other but carried in a housing that is movable (as contrasted to rigid assembly of one of the bearings` in, for example, a stationary frame). Each of the allochiral pairs of bearings, and the housing therefor, is in rigid connection with 2a lever arm extending therefrom and beneath the roll. These allochiral lever arms carry the entire lWeight of the roll, bearings and bearing housings, and such lever arms are in turn supported from beneath by means positioned inwardly from the roll ends. This force arrangement thus results in the application of force couples to the shaft elements tending to bow or dellect the roll upwardly. The exact contour which the axis of the roll will take depends, of course, upon the relative strength .of the roll and the load applied thereto; but in accordance with the instant invention it also depends upon and may be varied by radjustable positioning of the means supporting the lever arms.

It is, therefore, an important object of the instant invention to provide an improved assembly for mounting Ia roll subject to a load.

It is another object of the instant invention to provide an improved roll assembly wherein force couples are applied via shaft elements at the ends of la roll subject to a load in a predetermined manner based upon the location `of certain ladjustably positioned means carrying the weight of the roll.

Yet another object of the instant invention is to provide, in a mounting for a roll whose centroidal saxis is subject to ideiiection (said roll having shaft elements at opposite ends thereof), in combination, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto (for deflecting the axis), :allochiral lever arms rigidv with each of said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, and means positioned inwardly fr'om the roll ends supporting the lever arms and the roll :carried thereby.

Other and Ifurther objects, features and advantages of the instant invention will become apparent to those skilled in the art from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

On the drawings:

FIGURE 1 is a diagrammatic illustration showing the two lower rolls of a stack ofrolls, illustrating in exaggerated fonm the manner in which such rolls may be deflected during a specic correlation among the essential control factors in a calender `stack of the prior art;

FIGURE 2 is a diagrammatic illustration similar to V FIGURE 1, but showing mounting means of the invention for a roll subjected to a load tending to cause deilection; and

FIGURE 3 is an end elevational View taken substantially from the right hand side of FIGURE 2.

As shown on the drawings:

In FIGURE l, a bottom portion of a calender stack, indicated :generally by the refe-rence numeral 1d, is shown comprising a king roll 11 at the bottom mounted on suitable bearings 12 and 13 which are in turn -iirmly secured to a iixed mounting such as a iloor F. Immedh ately above the king roll 11 is ya calender roll le which, in turn, is mounted -for rotation in bearings 1S and 16. Actually, the roll 1l is provided with a left hand stub shaft 11a or shaft element which is rotatably received by the left hand 'bearing 12 and a .right hand stub shaft 11b which is rotatably received by the right hand bearing 13. The roll 14 is also provided with a left hand stub shaft 14a rotatably received by the left hand bearing 15 and a right hand stub shaft lfib rotatably received by the right hand bearing 16.

As will fbe noted, the axis X-ll lfor the roll i1 is defiected downwardly below a horizontal or center line Cdl at the `middle of the roll l1 'and this is caused by the load applied to the roll l1 by the weight of the roll 1d- (and any other rolls thereabove). This weight is transmitted through the sheet of paper (shown in exaggerated thickness at W-l) passing through the nip bctween the lrolls il. and 14. In the calender 1i), however, the central portion of the top surface of the roil 1i is still crowned so as to extend a distance R-11 above the outer extremities of the roll il, and the bottom surface of the roll is downwardly Ibowed still a greater distance D-ll. The amount of operating crown 1?.-11 depends upon the amount of original crown formed on the roll 11 and the total weight of the calender stack of rolls 14, etc. mounted therea'bove. As will be appreciated, if it is desired to operate a calender with substantially no operating crown (R41) in the king roll 1i, the initial crown of the king roll 11 and the total weight of the calender rolls 14, etc. are correlated so as to obtain :substantially no `operating crown. If, however, it then becomes desirable to make a change in the operation of the prior art calender yby using less calender rolls in the stack, then a greater operating crown R-11 will be obtained. This may possibly result in an undesirable pressure distribution at the portion of the web W-l passing through the nip Isl-1. The same is true with respect to variations in load which may 'be applied to any other crowned roll in a paper machine or other device.

In many of such prior art devices, the crown initially formed on the roll being subjected to the load is just sufcient to permit the roil to deflect in response to this predetermined load to such an extent that the roll presents a substantially iiat (usually horizontal) nip defining surface. It will be appreciated that any variation from such predetermined load will, however, necessarily result in a devi-ation from the desired flat or Alevel contour of the operating surface or nip defining line of the roll (herein designated llc).

Referring now to FIGURE 2, it will be seen that the apparatus of the instant invention is adapted to mount a roll 21 whose centroidal axis in the unloaded condition of roll (C411) is subject to deflection. It will be appreciated that the deflections and crowns indicated in FIGURES 1 and 2 are greatly exaggerated for purposes of simplifying the disclosure.) As indicated diagrammatically in FIGURE 2, the axis C-2'1 is -a center line for the roll 21 which would be a substantially straight, horizontal line in the View of FIGURE 2, if the roll 21 were not subjected to any loading forces including the load of its own weight. The roll 21 is, however, subjected to a load across its entire width, including the load of its weight and the load applied by an upper roll (shown partially at 24 in FIGURE 3 and represented in FIGURE 2 diagrammatically by arrows 24a and 24h at the quarter points and 24C at the center of the roll 21, although such load 24a, b, c is actually applied uniformly across the entire width of the roll 21). As indicated in FIGURE 3, a paper web W-2 traveling along the surface of the upper roll 24 (shown fragmentarily) passes downwardly and into a nip N2 between the

rolls

21 and 24 and then outwardly from the nip N-Z.

As shown in FIGURE 2, the roll 21 has shaft elements or stub shafts 2da and 2lb at opposite ends thereof. Ailochiral pairs of bearings (shown diagrammatieally as axially spaced bearings 22a, b as the left hand pair and 23a, b as the right hand pair) rotatably receive the stub shafts 21a and 2lb respectively. The right hand pair of bearings 23a, 23b rotatably receive the stub shafts 21a and 2lb respectively. The right hand pair of bearings 23a, 23b rotatably receives the stub shaft 2lb, with the bearings 23a and 2311 spaced each other so that they are adapted to apply a force couple in a generaiiy vertical piane of the roll axis C-21 and the load Zita, b, c (such couple being represented diagrammatically above the bearings 23a, 23h at FC-l). The bearings 23a and 231') are securely mounted in a conventional housing 23, so that the bearings 23a and 2311 will maintain a predetermined spaced relationship (sufficiently close to the retained conveniently in a single housing 23). The bearings 22:1 and 22h are, likewise, mounted in a housing 22. A lever arm 25 that is rigidly connected to the housing 23 (which in turn is rigidly connected to the bearings 23a, 2311) extends from the housing 23 and bearings 23a, 23h downwardly at 25a and then inwardly from the right hand end of the roll 2l and beneath the roll 21, at 25h. The portion 25h of the lever arm 25 extending beneath the roll 21 is mounted on `a suitable carriage 26, which is here shown mounted on track means 28 aligned generally parallel with the center axis C-21 of the roll 21. The carriage 25 preferably comprises a means for readily adjusting the position of the load, eg., a roll pyramid system consisting of a plurality of spaced lower rollers 26a, 26h on tbe track 28 carrying a plate 26e which in turn mounts one or more top rollers 26d directly supporting the total load via the arm 25h. Conventional adjustable positioning means (such as a jack screw device or the like indicated diagramrnatically at 29) move the carriage 26 to the exact location desired on the track 23. r[he track means 23 are secured to a rigid support S. As is apparent `from FIGURE 2, the left yhand pair of bearings 22a, 22b are mounted in a substantially symmetrical assembly wherein parts corresponding to the right hand mounting assembly are designed by the prime of the same reference numeral.

It will be noted that the entire weight of the roll 21, plus the load (24a, 24b, 24C) applied thereto is carried by the allochiral pairs of bearings 22a, b and 23a, b, which are in turn carried by the

allochiral lever arms

25, 25 rigidly secured to the pairs of bearings. The load thus transferred to the

lever arms

25, 25 is in turn carried by the carriage means 26, 26'. As indicated, the carriage means 26, 2.6 are effectively positioned at 30, 30 approximately beneath the quarter points (designated respectively at 24h and 24a in FIGURE 2) of the roll 21. This results in a substantial straightening out of the roll 21 so as to obtain an axial alignment A-21 shown in dashed lines to deviate from the center line C 21 in greatly exaggerated manner. -In the absence of this straightening out effect of the invention, the axis of the roll 21 wouid deflect centrally under the load 24 along a dot-dash line B-21 also shown to deviate from the center line C-21 in greatly exaggerated manner.

`In actual practice, these deviations from the center line C-21 are very small numerically but their effects are significant. The center line A-21 is really substantially straight, so as to present for loading a substantially horizontal straight top surface 21C for the roll 21. The application of the force couple FC-l at the right hand side will tend to deflect the center line A-21 slightly upwardly at the right hand quarter point 24h; and the opposite couple FC-2 tends to deflect the center line A-21 slightly upwardly at the left hand quarter point 24a. The unsupported center of the roll 21 will respond to the load 2d much like a normal beam and will deflect centrally downwardly slightly (at 24e). This configuration A-21 is, however, substantially straight for practical purposes (and much more straight than the normal beam deection line B-21); and it involves a minimum average deviation from the theoretical ccnter line C-21.

As indicated in FIGURE 2, the effective support point 30 for Ithe carriage 26 is midway between the wheels 26a, `Zeb and substantially opposite the quarter point 24b. In most instances, this is preferable for obtaining a minimum average deviation from the theoretical center line C-.ZI by having a peak upward deflection in the actual center line A-21 at approximately the quarter point 24h. But the invention provides the additional advantage of extremely line control by adjusting means 29. The carriage 26 is movable preferably in a region inwardly from the roll end or shaft 2lb but outwardly from the roll center (at 24C), approximately in the region of the quanter point 2421!; (which might be expressed numerically as within the region of of the roll length on either side of the quarter point, i.e., to of such roll length inwardly from each end).

An additional advantage of the invention resides in the fact that the force couple FC1 does not involve the application of an end or axially aligned load to the bearings 23a, b; lwhich allows for changes in the overall length of the roll 21 due to operating temperature changes, and lwhich minimizes bearing wear.

ln addition, it will be noted that the roll 2l is preferably a driven roll (although not necessarily). For this purpose a drive tang 31 is connected in conventional manner to the stub shaft 2lb and extends out of the housing 23 to engage suitable drive means indicated diagrammatically at 32.

As indicated fragmentarily in FGURE 3, vertical stabilizing

means

33, 33 are preferably provided for the housing 23, in the form of tracks slidably receiving the housing 23 and permitting vertical movement.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

I claim as my invention:

l. In a mounting for a roll having a substantial lengthto-diameter ratio whose axis is subject to deflection, said roll having shaft elements ait opposite ends thereof, in combination, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid -with each of said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, and means positioned appreciably inwardly from the roll ends supporting the full weight of the lever arms and of the roll c-arried thereby.

2. ln a mounting for a roll whose axis is subject to eilection, said roll having shaft elements at opposite ends thereof, in combination, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll and `toward the other of said pairs of bearings, said arms supporting the weight of the roll and said bearings, and means positioned inwardly from the roll ends supporting the lever arms from beneath and applying such force couple to said shaft elements.

3. In a mounting for a roll whose axis is subject to deflection, said roll having shaft elements at opposite ends thereof, in combination, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid with each of said pairs of |bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, said arms supporting the weight of the roll and said bearings, and means positioned inwardly from the roll ends, supporting the lever arms from beneath and applying such force couple to said shaft elements, said means being independently shiiitable generally parallel to the axis of the roll.

4. In a mounting for a roll Whose axis is subject to deiiection, said roll having shaft elements at opposite ends thereof, in combination, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, track means aligned generally parallel to the roll axis, and carrier means movable in` said track means, said carrier means being positioned inwardly from the roll ends, supporting the lever arms from beneath and applying such force couple to said shaft elements. Y

5. In combination, a roll having a substantial length- Vto-diameter ratio and whose axis is subject to deflection, said roll having shaft elements at opposite ends thereof, mea-ns applying a load to said roll tending to effect deection of the roll axis, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid with each of -said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, and means positioned appreciably inwardly from the roll ends supporting the weight of the lever arms and of the roll carried thereby.

6. In combination, a roll whose axis is subject to deection, said roll having shaft elements at opposite ends thereof, means applying a load to said roll tending to effect deflection of the roll axis, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, track means aligned generally parallel to the roll axis, and carrier means movable in said track means, said carrier means being positioned inwardly from the roll ends, supporting the lever arms from beneath and applying such force couple to said shaft elements.

7. In combination, a roll whose-axis is subject to deflection, said roll having shaft elements at opposite ends thereof, means applying a load to said roll tending to effect deflection of the roll axis, allochiral pairs of bearings rotatably receiving said shaft elements andv adapted to apply a force couple thereto, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll and toward the other of said pairs of bearings, and means positioned inwardly from the roll ends supporting the lever arms from beneath and applying such force couple to said shaft elements.

8. In a mounting for a roll having a substantial lengthto-diameter ratio and whose axis is subject to deflection, said roll having shaft elements at opposite ends thereof, in combination, allochiral pairs of .bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, allochiral housing elements rigid with each of said pairs of bearings and maintaining a spaced relation between the bearings of each pair, allochiral lever arms rigid with each of said housing elements and the pair of bearings maintained in spaced relation thereby and extending downwardly from said housing elements beneath the roll and toward the other of said pairs of bearings generally in a vertical plane passing through the centroidal axis of the roll, and means positioned approximately 15% to 35% of the roll length inwardly from the roll ends supporting the Weight of the lever arms and of the roll carried theerby.

References Cited in the le of this patent UNITED STATES PATENTS

Claims

1. IN A MOUNTING FOR A ROLL HAVING A SUBSTANTIAL LENGTHTO-DIAMETER RATIO WHOSE AXIS IS SUBJECT TO DEFLECTION, SAID ROLL HAVING SHAFT ELEMENTS AT OPPOSITE ENDS THEREOF, IN COMBINATION, ALLOCHIRAL PAIRS OF BEARINGS ROTATABLY RECEIVING SAID SHAFT ELEMENTS AND ADAPTED TO APPLY A FORCE COUPLE THERETO, ALLOCHIRAL LEVER ARMS RIGID WITH EACH OF SAID PAIRS OF BEARINGS AND EXTENDING THEREFROM BENEATH THE ROLL AND TOWARD THE OTHER OF SAID PAIRS OF BEARINGS, AND MEANS POSITIONED APPRECIABLY INWARDLY FROM THE ROLL ENDS SUPPORTING THE FULL WEIGHT OF THE LEVER ARMS AND OF THE ROLL CARRIED THEREBY.