US3082685A - Roll deflection - Google Patents

Description

March 26, 1963 L. A. MOORE ROLL DEFLECTION Filed March 8, 1961 INVENTOR. Lawrence 14({718/06 Moore BY 7 WWI, ZfMEORN/EYS United States Patent. Ofiice 3,082,685 Patented Mar. 26, 1963 3,082,685 RGLL DEFLECTION Lawrence A. Moore, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Mar. 8, 1961, Ser. No. 94,262 8 Claims. (Cl. 100-155) This invention relates to apparatus for mounting a roll whose axis is subject to deflection, and more particularly,

to an apparatus for mounting a roll that is subjected to a load tending to eifect central deflection of the roll axis.

Although the instant invention may be useful in a number of arts, it is particularly 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 which are subjected to loads tending to deflect such rolls centrally. For example, wire return rolls in a Fourdrinier paper machine are subject to a load tending to effect central deflection thereof by virtue of the weight of the rolls themselves and of the Fourdrinier wire carried by the rolls, the tension on the Fourdrinier Wire, and, in the case of a driven roll, the force component resulting from the resistance or reaction of the wire itself to the driving force. These forces tend to deflect 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 deflection of the return roll in one manner or another.

In addition, in pressv 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 and deflect the same centrally downwardly. Such deflection results in an undesirable application of forces across the nip and other undesirable operating features; and such deflection is often corrected in paper machines by crowning of the lower roll. The crowning of the roll requires accurate and expensive finishing 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 a different set of force conditions. Accordingly, crowning of rolls often does not afiord satisfactory operation for many different types of operating conditions.

In other arts relating to paper machines, such as the coating of paper or fabrics with plastic materials, pressure or calender rolls are also used. Also, paint mixing roll systems or the like are subject to the buildup of forces in the central portion of pressure nips which tend to cause central deflection of the rolls and result in nonuniform and/ or other undesirable conditions across the width of such press nips.

The instant invention affords a simple but 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 allochiral pairs of bearings mounting a roll, Le, a right hand pair and a left hand pair of bearings rotatably receiving stub 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 referredto herein as allochira 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 a force couple thereto, wherein one of the bearings is fixed and the other movable, is shown in the prior art, for example, in Goulding US. Patent No. 2,611,150.

In the instant invention, however, both of each pair of hearings in the assembly used to apply a force couple to the shaft are bearings fixed with respect to each other but carried in a housing that is movable (as contrasted to rigid assembly of one of the hearings in for example a stationary frame). Each of the allochiral pairs of bearings, and the housing therefor, is in rigid connection with a lever arm extending therefrom to terminate adjacent the other of said pairs of bearings. Each bearing housing is pivotally mounted for a rocking type of movement required to exert the force couple, and the lever arm rigid with such housing is used to effect this rocking movement. A particular advantage of the instant invention resides in the extension of the lever arm from the housing rigid therewith at one end of the roll to the opposite end of such roll, for the reason that this extension of the lever arm provides a distinct mechanical advantage in the application of the very great forces required for the force couple. This positioning of the lever arm also 'makes possible an excellent weight and positional arrangement for delicate control. The extension of the terminal I portion of the lever arm beneath the roll and to the opposite side thereof makes possible the mounting of the actuating or positioning means for the terminal portion of the lever arm completely outside the effective operating area of the roll. The actuation of such lever arm (which is ordinarily done by a generally vertically aligned actuator at the terminal portion thereof) also does not involve the application of an end thrust to the bearings applying the force couple.

The force arrangement thus employed results in the application of force couples to the shaft elements tending to bow or deflect the roll in the desired direction, which is generally opposite to the direction of application of the "load. 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 the force couples applied at the shafts at opposite ends of the roll. In the present force arrangement, the force couple is applied via the lever arm (which does not carry the weight of the roll) and the weight of the roll is carried via pivot means associated with each of the bearing housings at opposite ends of the roll.

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

It is another object of the instant invention to provide an improved roll assembly wherein force couples are ap- 'plied via shaft elements at the ends of a roll subject to load in a predetermined manner which affords delicate and accurate application of the force couples by actuating means remote from the operating area of the roll itself.

Yet another object of the instant invention is to provide, in a mounting for a roll whose centroidal 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, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms to apply such force couple to said shaft elements.

Other and further objects, features and advantages of the present 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 of rolls, illustrating in exaggerated form the manner in which such rolls may be defiected during specific correlation among the essential control factors in a calender stack of the prior art;

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

FIGURE 3 is an end elevational view taken substantially from the right hand side of FIGURE 2; and

FIGURE 4 is a top sectional view taken along the line IVIV of FIGURE 2.

As shown on the drawings:

In FIGURE 1, a bottom portion of a calender stack, indicated generally by the reference numeral 10, is shown comprising a king roll 11 at the bottom mounted on suitable bearings 12 and 13 which are in turn firmly secured to a fixed mounting such as a floor F. Immediately above the king roll 11 is a calender roll 14 which, in turn, is mounted for rotation in bearings 15 and 16. Actually, the roll 11 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 14b rotatably received by the right hand bearing 16.

As will be noted, the axis X-11 for the roll 11 is defiected downwardly below a horizontal or center line C-ll at'the middle of the roll 11 and this is caused by the load applied to the roll 11 by the weight of the roll 14 (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 between the rolls 11 and 14. In the calender 10, however, the central portion of the top surface of the roll 11 is still crowned so as to extend a distance R-ll above the outer extremities of the roll 11, and the bottom surface of the roll 11 is downwardly bowed still a greater distance D11. The amount of operating crown R-ll 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 thereabove. As will be appreciated, if it is desired to operate a calender with substantially no operating crown (R-ll') in the king roll 11, 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 by using less calender rolls in the stack, then a greater operating crown R-ll will be obtained. This may possibly result in an undesirable pressure distribution at the portion of the web W-l passing through the nip N-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 sufficient to permit the roll to deflect in response to this predetermined load to such an extent that the roll presents a substantially flat (usually horizontal) nip defining surface. It will be appreciated that any variation from such predetermined load will, however, necessarily result in a deviation from the desired flat or level contour of the operating surface or nip defining line of the roll (herein designated 11c).

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 the roll; (C -21) is subject to deflection. As will be appreciated, the extent of deflection and crown has been greatly exaggerated in FIGURE 1 and will also be exaggerated in the description of FIGURE 2 for the purpose of simplifying the nature of the disclosure. As indicated diagrammatically in FIGURE 2, the axis (3-21 is a center line for the roll 21 which would be a substantially straight, horizontal line in the view of FIG- URE 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 24b at the quarter points and 240 at the center of the roll, 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 N-2 between the rolls 21 and 24 and then outwardly from the nip N-2.

As shown in FIGURE 2, the roll 21 has shaft elements or stub shafts 21a and 21b at opposite ends thereof. Alloohiral pairs of bearings (shown diagrammatically 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 21b respectively. The right hand pair of bearings 23a, 23b rotatably receives the stub shaft 21b, with the bearings 23a and 23b spaced from each other so that they are adapted to apply a force couple in a generally vertical plane of the roll axis 021 and the load 24a, b, c (such couple being represented diagrammatically above the bearings 23a, 23b as FC-l). The bearings 23a and 23b are securely mounted in a conventional housing 23, so that the bearings 23a and 23b will maintain a predetermined spaced relationship. The bearings 22a and 2212 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, 23b) extends from the housing 23 and the bearings 23a, 23b downwardly at 25a and then inwardly from the right hand end of the roll 21 and beneath the roll 21 at 25b the full width of the roll 21 to terminate, at 250 in the region of the opposite pair of bearings 22a, 22b, and preferably beyond the left hand extremity of the roll 21.

The housing 23 is pivotally mounted, on a fixed pivot P, for limited rocking movement. The pivot P is preferably positioned intermediate the bearings 23:; and 23b. A left hand fixed pivot P carries the housing 22 and the bearings 22a and 22b rigid therewith in like manner. The pivot P and P carries substantially the entire weight of the roll 21, the bearings 22a, b and 23a, b and the load 24a, b, c.

As is apparent from FIGURE 2, the left hand pair of bearings 22a, 22b are mounted in a substantially symmetrical assembly wherein parts corresponding to the right hand mounting assembly are designated by the prime of the same reference numeral.

The terminal portion 250 of the lever 25' is equipped with means for acting thereon to apply the force couple FC-l to the shaft element 21b. The means provided herein is a fluid pressure actuated diaphragm 26 mounted on a fixed supporting surface S. The diaphragm 26 is adapted for limited vertical movement of the lever terminal portion 256. The right hand lever terminal portion 250 is also equipped with a fluid pressure actuated diaphragm 26 which functions in like manner. The diaphragms 26, 26 are conveniently located away from the operating area of the roll 21 (which will be primarily the peripheral surface thereof and the region immediately above and below). In addition, the length of the lever arm portions 25b and 25b is very substantial so as to provide the most favorable mechanical advantage for the operation of the levers 25, 25' so as to permit extremely delicate control of the application of both the right hand force couple (PC-1) and the left hand force couple UFO-2). The force couples (FC-l, 2) are shown diagrammatically to indicate the manner in which the force couples are applied to corresponding stub shafts 21a, 21b

when an upward force is applied to the terminal lever portions 250, 25's by the diaphragms 26, 26'. This results in a substantial straightening out of the roll 21.

As will be appreciated, in the absence of such straightening out efiiect the centroidal axis of the roll 21 would deflect centrally under the weight of the roll 21 and the load 24 along a dot-dash line B21 shown to deviate from the theoretical center line C-21 in greatly exaggerated manner in FIGURE 2. In actual practice, such a deviation from the center line C-21 is very small numerically, but the effect thereof may be quite significant. Among other things, it may cause the presentation of a non-horizontal top surface 21c for the roll 21.

In the practice of the instant invention, however, it is possible to correct the normal tendency of the roll 21 to deflect so as to obtain a centroidal axis indicated in dash lines at A-21 (but also deviating in greatly exaggerated manner from the theoretical center line C-21). The application of the force couple FC-l of the right hand side will tend to deflect the center line A-21 slightly upwardly along the right hand side, here indicated at approximately the quarter point 24b. The opposite couple FC-2 tends to deflect the center line A-21 slightly upwardly at the left hand side, here indicated at approximately the quarter point 24a. The unsupported center of the roll 21 will respond to the load 24 much like a normal beam and will deflect centrally downwardly slightly (at 240). This configuration A-21 is, however, substantially straight for practical purposes (and much more straight than the normal beam deflection line B-21); and it involves a minimum average deviation from the theoretical center line C-21.

It will be appreciated that under certain preferred conditions it may be possible to adjust the diaphragms (26, 26) so as to obtain what may be an ideal configuration for certain paper machine uses in the form of the axis configuration A-21. In other instances, it may be desirable to impart an overall crown to the upper surface 21c of the roll 21, and this can be done by applying difierent forces through the force couples and using different load combinations on the roll 21. Also, should it be desirable to bow the operating surface 21c downwardly for the roll 21, this can be done by applying reverse forces to the bearing couples 22a, b and 23a, b. A particular advantage of the instant invention resides in the delicate control which is permitted by the use of the present lever arm arrangement with improved mechanical advantage. Another improved feature of the invention resides in the fact that the force couples FC-l, 2 do not involve the application of an end or axially aligned load to the bearings 22a, b or 23a, [2, and this permits limited changes in the overall length of the roll 21 due to operating condition changes such as temperature changes. This arrangement also minimizes bearing wear.

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:

1. 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, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms to apply such force couple to said shaft elements.

2. In a mounting for a roll whose axis is subject to de- 6 flection, 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, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom to terminate adjacent the other of said pairs of bearings,

and diaphragm means for acting on the terminal portions of each of said lever arms to apply 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, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms to apply such force couple to said shaft elements.

4. In a mounting for a roll whose axis is subject to deflection, said r-oll having shaft elements at opposite ends thereof, in combination, allochiral pairs of bearings rotatably receving said shaft elements and adapted to apply a force couple thereto, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms in a direction generally normal to the axis of said roll to apply such force couple to said shaft elements.

5. 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 eflect deflection of the roll axis, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, fixed pivots mounting each of said pairs of bearings, allochiral lever arms rigid with each of said pairs of bearings and extending there from to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms to apply such force couple to said shaft elements.

6. In combination, a generally horizontally aligned roll whose axis is subject to deflection downwardly in the contral portion of the roll, means applying a load to the top of the roll tending to effect such deflection, allochiral pairs of bearings rotatably receiving said shaft elements and adapted to apply a force couple thereto, fixed pivots mounting each of said pairs of bearings carrying the roll Weight and such load, allochiral lever arms rigid with each of said pairs of bearings and extending therefrom beneath the roll to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms in a generally vertical direction to apply such force couple to said shaft elements.

7. 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 housing elements rigid with and receiving each of said pairs of bearings and maintaining a spaced relation between the bearings of each pair, fixed pivots mounting each of said housing elements, allochiral lever arms rigid with each of the housing elements and extending therefrom to terminate adjacent the other of said pairs of bearings, and means for acting on the terminal portions of each of said lever arms to apply such force couple to said shaft elements.

8. 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 8 effect deflection of the roll axis, allochiral pairs of bearpairs ofbearings, and means for acting on the terminal ings rotatably receiving said shaft elements and adapted portions of each of said lever arms to apply such force to apply a force couple thereto, allochiral housing elecouple to said shaft elements. ments rigid with each of said pairs of bearings and maintaining a spaced relation between the bearings of each 5 Refefelwes Cited in the file Of this patent pair, fixed pivots mounting each of said housing elements, UNITED STATES PATENTS allochiral lever arms rigid with each of said housing elements and pairs of bearings contained therein and extend- 235-05952 Sept 1958 ing therefrom to terminate adjacent the other of said 2897538 Shaplro et a1 1959

Claims (1)

1. 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, FIXED PIVOTS MOUNTING EACH OF SAID PAIRS OF BEARINGS, ALLOCHIRAL LEVER ARMS RIGID WITH EACH OF SAID PAIRS OF BEARINGS AND EXTENDING THEREFROM TO TERMINATE ADJACENT THE OTHER OF SAID PAIRS OF BEARINGS, AND MEANS FOR ACTING ON THE TERMINAL PORTIONS OF EACH OF SAID LEVER ARMS TO APPLY SUCH FORCE COUPLE TO SAID SHAFT ELEMENTS.

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