United States Patent: 3554118

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United States Patent	3,554,118
Laine	January 12, 1971

RELIEF AND RAISING DEVICE ARRANGEMENT IN MULTINIP CALENDER

Abstract

A relief and raising device arrangement in a multinip calender or calender stack, in which upon a stationarily rotatable lower roll are mounted two or more superimposed rolls which are pivotably attached by arms to the calender body and in which each roll has its individual relief device attached to a common raising device. The relief devices are so attached to the raising device that the raising device will through the pneumatically regulated relief device constantly be in connection with the roll and that an adjustable free spacing for movement of the relief devices increases in the downward direction. The raising device is preferably a rod movable in vertical direction and attached to the lower or upper part of the calender body.

Inventors:	Laine; Paavo J. (Tampere, SF)
Assignee:	Oy Tampella Ab (Tampere, SF)
Appl. No.:	04/704,909
Filed:	February 12, 1968

Current U.S. Class: 100/163A ; 100/170

Current International Class: D21G 1/00 (20060101); B30b 003/04 ()

Field of Search: 100/163,163A,170

References Cited [Referenced By]

U.S. Patent Documents


2850952	September 1958	Hornbostel
3044440	July 1962	Molsberry et al.
3155029	November 1964	Thomas
3158088	November 1964	Seidel
3270664	September 1966	Veneman et al.

Foreign Patent Documents


1,150,272	Jun., 1963	DT

Primary Examiner: Blum; Daniel

Claims

I claim:

1. In a paper machine a multinip calender, comprising a calender body, a stack of calender rolls including a bottom roll and a plurality of superimposed rolls, separate and independent bearings rotatably carrying the ends of each of said superimposed rolls and separate arms pivotably attached to the calender body and independently carrying said bearings and independent pneumatic relief devices urging each of said bearings upwardly, said relief devices comprising expandable bellows elements, a common raising device coupled to said relief devices, said raising device being attached to the calender body for raising and lowering said bearings and being constantly in contact through said relief devices with said bearings, said relief devices having a free spacing increasing in the downward direction.

2. A multinip calender as claimed in claim 1, wherein each of said superimposed rolls is mounted at the end of one arm of a lever pivotably attached to said calender body, said raising device is provided at the opposite side of the body from said rolls and the said relief devices are pivotably in connection with the ends of opposite arms of said levers.

3. A multinip calender as claimed in claim 1, wherein said superimposed rolls are mounted on levers pivotably attached to said calender body and said relief devices are pivotably secured to free end of said levers.

4. A multinip calender as claimed in claim 1, wherein the free spacing for movement of said relief devices is adjustable.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a portion of the paper machine known as calender or calender stack and more particularly, to an improvement in a multinip calender.

2. Description of the Prior Art

U.S. Pat. Nos. 2,850,952 and 2,985,100 disclose hydraulically or pneumatically operated relief devices, which act on the end of a lever mounted on the body and extending to the side of the calender body opposite of the roll, and in which arrangement the raising device of the rolls acts on that end of said lever which extends toward the roll, that is on the opposite end with respect to the relief device. This arrangement has the drawback that in the event of paper accumulations squeezing into the nip between two rolls, the end of the lever facing toward the relief device loses connection with the hydraulic or pneumatic relief device, giving rise to shocks straining the device.

THE SUMMARY OF THE INVENTION

This invention relates to a relief and raising device arrangement in multinip calender stacks of the type in which upon a stationarily rotatable lower roll are mounted one upon the other two or more rolls which by means of pivotably attached arms are secured to the calender body and wherein individual relief devices for each roll and a common lifting device are provided. The object of the invention is to provide a relief device arrangement, which is simpler, more reliable and easier to operate than the prior known arrangements of corresponding type.

BRIEF DESCRIPTION OF THE DRAWING

The relief and raising device arrangement according to the invention is described more fully in the following with reference to the accompanying drawings, in which:

FIG. 1 shows a multinip calender stack provided with the relief and lifting arrangement according to the invention, in side elevation and in partial section;

FIG. 2 is a detail view of a single relief device in section;

FIG. 3 is a side view of the apparatus similar to the view of FIG. 1 and with some parts cut away to show internal structure;

FIG. 3a is a detail view of the lifting arrangement of FIG. 3 in transverse section;

FIG. 4 is a sectional view of the lower portion of the apparatus of FIG. 3 and taken at right angles to the view of FIG. 3;

FIG. 5 is a detail view, in section, of the relief device of the invention;

FIG. 6 is a view, in elevation, of a detail of the relief device;

FIG. 7 illustrates schematically an adjusting screw of the relief device of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In the drawing reference numeral 1 indicates a calender body, 2 is a bearing for the lower roll or king roll 3, reference numeral 4 indicates generally the rolls mounted upon the lower roll in the ends of arms 5 of levers. The levers are at points 6 pivotally mounted on the calender body 1, a driving means for a raising rod 7 being provided in the lower portion of said body. Beyond their pivot points 6, the levers have arms 20 which are longer than the lever arms 5, thus providing a mechanical advantage to the relief devices to be described in detail hereafter.

The actuating mechanism for the raising rod 7 includes a pin 8, which is pivotally secured to the lower end of the raising rod 7. A worm gear transmission mounted on the bed or floor upon which the calender rests is shown enclosed in a housing 10. An internally threaded fitting 9 rotatable by the worm gear transmission in housing 10 surrounds the pin 8 at its lower end and lifts or lowers the pin 8 by means of trapezoidal threads on the pin 8 engaging the internal threads of the fitting 9.

The drive means may obviously be any other mechanically or hydraulically operated suitable device.

At spaced locations along the lifting rod 7 there are provided adjustable mounted braces or lugs 11, below which the relief devices are mounted. Since the relief devices are arranged between the braces or lugs 11 and the ends of the lever arms 20 the expansion and contraction of the relief devices, braced by the lugs 11, serve to raise and lower the ends of the lever arms 20. The lever arms 20 are longer than the lever arms 5 to which they are secured at pivot points 6, so the lever arms 5 convey a fraction of the movement of the relief devices to the rolls 4, lifting or lowering the rolls. Each of the braces or lugs 11 bears a downwardly extending cylindrical element extending into the adjacent relief device.

The relief device comprises plates 14 and 15 joined together by a bellows 13 of annular form. The lower plate 14 is identical in all relief devices, and its upper surface, which remains inside the bellows, consists of an engaging surface 16, and its lower surface is provided with a central depression, into which penetrates a stud 18 having at its lower end a T-branch 19 of circular section. This T-branch is positioned in a recess 21 at the free end of one 20 of the arms of a lever. The relief devices are thus pivotally coupled at 19 to the free ends of the lever arms 20. The upper plate 15 has in its lower surface remaining inside the bellows 13 an engaging portion 22, the height of which increases from one relief device to the other in the upward direction. Both the lower and the upper plates are bored for weight reduction of the device. Thus the relief device is similar to a piston and cylinder arrangement, with an exterior bellows 13 cushioning its movements. Of course, it is the pneumatic action of the bellow which moves the ends of lever arms 20, through the coupling 19, but the bellows 13 is also effective to prevent the sudden jarring of the mechanism when a paper accumulation or "paper cud" passes between two rolls 4 of the calender. Because of the high speeds at which the rolls of modern calenders rotate, the import of a "paper cud" passing between two rolls is very forceful and might easily cause the failure of the raising mechanism if it were not for the shock absorbing effect of the bellows 13.

In the above described relief and raising device arrangement according to the invention the support force of the roll relief is not applied to the body but through the roll raising rod to the foundation, which reduces the strains on the body Sudden shocks, as in the case of the passage of a paper cud between tow rolls 4, are thus conveyed through the raising rod 7 to the worm gear transmission at 10 to the bed or foundation. The arrangement according to the invention can however be utilized with the raising rod secured to the upper portion of the body, in case the consequent additional strains on the body are deemed to be without greater importance.

Instead of using levers having pivot points 6 intermediate their ends as in the above description, it is also possible to utilize a relief and raising device according to this invention with a different class of lever. Thus the rolls 4 could be secured to levers which have fixed "fulcra" at one end and the raising and relief devices at their other ends, the rolls 4 being between the fulcra and the raising and relief devices.

The spacing between the engaging surfaces 16 and 22 of the relief device can be adjusted as required by raising or lowering the threaded member 12 in the lug 11. Since there is a mechanical advantage in the system the individual adjustment of the threaded cylindrical members 12 is done in multiples of the spacing which is desired between adjacent rolls 4. Also, because of the cumulative effect of the adjustments it will be clear that the uppermost lug or brace 11 will be closer to the end of the adjacent lever arm 20 than the next lower lug or brace 11, and so on in an aritmetical series of increasing distances. This spacing increases from one device to the other in downward direction just as in prior known structures, permitting consecutive disassembly of the rolls. The hydraulic or pneumatic pressure inside the bellows can of course be individually controlled in each device.

In the arrangement of this invention the relief devices constitute a part of the raising device, because of which the rolls 4 through the arms 20 and 5 are in continuous contact through the relief devices with the raising rod 7, and in the event of paper accumulations squeezing into the nip between two rolls this relief method and relief device arrangement provide more resilient shock absorption.

As has been stated above the invention is not restricted to the relief and raising device arrangement described above and shown in the drawings but can be varied within the scope of the following claims.

* * * * *

Current U.S. Class:	100/163A ; 100/170
Current International Class:	D21G 1/00 (20060101); B30b 003/04 ()
Field of Search:	100/163,163A,170