US3155029A - Calenders - Google Patents

Description

R. THOMAS Nov. 3, 1964 CALENDERS 4 Sheets-Sheet 1 Filed Dec. 24, 1962 INVENTOR.

Rex THOMAS ATTORNEYS Nov. 3, 1964 R. THOMAS & 9

CALENDERS Filed Dec. 24, 1962 4 Sheets-Sheet 2 I nw 10 M 25 2 IHIIH INVENTOR.

Rex THOMAS BY v %www/4 4 &

ATTORNEYS R. THOMAS CALENDERS Nov. 3, 1964 4 Sheets-Sheet 3 Filed Dec( 24, 1962 INVENTOR. Rex THOMAS i A TTORNE YS R. THOMAS 3,155,029

CALENDERS 4 Sheets-Sheet 4 Nov. 3, 1964 Filed Dec. 24, 1962 INVENTOR Rex THOMAS A TTORJVE YS United States Patent O &1555929 CALENDERS Rex Thomas, Terrasse Vandreuil, Quebec, Canada, as-

signor to Dominion Engineering Works Limited, Montreni, Quebec, Canada Filed Dec. 24, 1962, Ser. No. %6,784 Claims priority, application Canada Nov. 2'2, 1962 6 Claims. (Ci. lihi-170) This invention relates to calender stacks and more particularly to open-side calender stacks as used in the p per making and other industries for calendering material in sheet, web, or strip form.

Although this invention is described as embodied in a cflender stack for use in the paper making industry, it will be understood that the principles and features described herein may be employed in calenders designed :for use in `the textile, p las-tic and other industries, where regulation of the calender roll nip-pressure is an important factor.

One conventional method for obtaining relief of nip pressures in closed calender stacks, includes fluid diaphrag-ms positioned on the tops of the roll bearing housings. When pressure is applied to these fluid diaphragms, upward lifting forces are exerted on the roll bearing housings positioned immediately above.

A disadvantage inherent in this method is tha-t the whole system is interdependent. The reactions to the nip-relieving -pressures are transferred to the hearing .housings immediately below and, as this effect is cumulative, the lower roll bearings support the resultant load from all the nip-relievng pressures, resulting therefore in excessive hearing and fluid diaphragm sizes.

Another disadvantage is that the procedure of removing rolls from the calender stack is extremely complicated.

Another known method for obtaining partial relef of nip pressures in closed calender stacks, includes two p-airs of vertical tubes arranged within the calender frame columns, one pair being positioned on each side of the calender. The upper ends of the tubes are connected to istons within fluid pressure cylinders, and attached to the lower ends of each pair of tubes is a yoke which car- -ries a roll hearing housing. Mounted coaxially within thetubes are sha-fts, which are also connected at their upper ends to pistons within fluid pressure cylinders. These sh afts project below the lower ends of the tubes and also carry yokes' adjustably positioned between each pair of sha fts for mounting roll hearing housings thereon@ Thus the stack of-rolls is divided into two sections and it is possible to vary the nip-pressures between each section of rolls by varying the pressures in the fluid cylinders.

The maindisadvantage with this method is that this system becomes objectionably. complexif .the stack is required to be divided into more than two sections, making it impract-icable, therefore, to obtain nip-relief on all rolls. v e

Another disadvantage is that large diameter interme- 'diate rolls are required at the stack divisions.,

A further conventional method for obtaining relief of nip-pressures in open-side calender stacks, includes arms :pivotal-ly mounted at their mici-positions on the calender frames. The roll bear-ing housings are mounted on ,one end of the arms and, attheir op posite ends, the arms are connected to air diaphragms which are operably connecte on the opposite endof the arms. a

To facilitate roll lifting, for separation of nips, etc., links are connected between each hearing housing with ;of the calender.

the upper bearing housing links connected to lifting means. Slots in .the links allow for roll separation when the rolls are lifted. In this conventional nip-relieving arrangement, the lifting links and the nip-pressure relieving diaphragms, are both mounted outside the calender frarne structure.

A disadvantage in the last mentioned conventional method is that the bearng housings, being positioned between the connecting links, are themselves utilized as connecting means. Therefore, when rolls are removed from the stack for re-grnding purposes, etc., it is necessary to install longer conneoting links to replace the bearing hous ings of the removed rolls.

Another di sadvantage is that the roll removal procedure is complicated by the need to remove mechanical 'links and pins in order to d isconnect the hearing housings from hearing housings immediately above and beow.

A further disadvantage is that the air diaphragms are Very bulky andproject beyond the calender fra-me structure, therefore being very susceptible to dama-ge. k

It is the main object of this invention to provide, in an open-side calender, a mechanism which performs the functions of roll lifting, nip-relieving and nip-loading, and in which the said mechanism is totally enclosed in the calender frame structure.

Another object is to provide a mechanism which permits the calender to be operated with less than the full number of roll-s in the stack app lying nip-pressures, without the need for additional roll litting equipment.

Another object is to provide an .open-side calender in which intermediate rolls may be removed from the stack, without the need for disconnect-ing the roll lifting mechansm.

Another object is to improve the efliciency of roll removal in open-side calenders by providing a calender design featuring no obstruction above the roll stack.

A further object is to provide an enclosed and compact open-side calender design, providing improved 'ap-` pearance and permitting more eflicient operation.

These .objectives are embodied in this invention by providing a calender roll nip-pressure regulatin-g means which includes pivotally mounted lever arms mounted in pair-s, one arm of each pair being mounted on each side A calender rol-l is supported between the ends of the arms on one side of their p ivots, and the ends' of the armsrcmote from the calender roll are connected to vertical-ly extending and vertically movable operating members, by means' of fluidpressure responsive devices. The fluid pressure responsive devices 'are arran ged to exert Upward or downward pressure on the calender roll by applying, respectively, downward or upward pressures on the ends of the arms remote from the calender roll. r

The vertical-ly extending and vertically mova ble operting members are also arranged to open the nip-s between the calender rolls, from thetop of the stack pro gressively downwards, whenlthe Operating members aremoved progressively downwards. A These. features are characterized in the preferred execution of this invention by mounting each calender roll, above the'bottomor king roll, on -the ends of arms pivotally mounted on the calender frarne structure. The ends of the pivotaily mounted arms remote from' the calender rolls are connected to vertcal operating orlifting screws, positioned one on each side of the calender, by means of fluid cylinder and piston devices, the ends of the arms being connected to piston'rods attached to the Pistons and the head-ends of the cyiinders being atjtache d to the lifting screws bymeans of positioning brackets Pressure fluid applied to either the head-ends or the red-ends of the fluid cylinders provides either,

&155329 downward or upward forces respectively on the ends of the pivotally mounted arms, resulting in either decrease or increase in the calender roll nip-pressure&

The lifting screws are threaded externally and the positioning brackets are threaded internally and adjustably positioned on the lifting screws, to provide progressively increasing distances, from the top calender roll position downwards, between the pistons in the fluid cylinders and the head-ends of the fluid cylinders. Separation of the calender roll nips is accomplished by lowering the lifting screws by means of screwjacks. This results in the exhaustion of the fluid above the pistons in the uppermost cylinders, whereupon the pistons bottom at the head-ends of the cylinders to form solid links between the lifting screws and the arms. Further lowering of the lifting screws forces the ends of the pivotally mounted arms, which are connected to the piston rods, downwards, therefore lifting the top roll. The positioning of the positioning brackets on the lifting screws provides for progressive lifting of the rolls, from the top to the bottom of the stack, as the lifting screws are lowered still further.

An alternative arrangement of this invention provides onlyfor relief of the nip-pressures and uses the same basic arrangement as used in the preferred execution, except that the pivotally mounted arms each comprise two members, each member being pivotally` mounted on the same pivot. The two arm members have nnilateral abutments which contact to provide a lifting force on the roll when a downward force is applied to the end of the arm member which is attached to the piston rod in the fluid cylinder and piston device. The unilateral abutments are free to separate to allow the roll to be lii'ted by means other than the cylinder and piston device, such as when a lump of paper stock passes through the roll nip.

A preferred embodiment of this invention is illustrated by way of example in the accompanying drawings i for accomplishingroll lifting.

FIG. 5 is a part sectional view, showing details of an alternative arrangement of the present invention.

' FIG. 6 is a sectional plan View taken on 6-6 in FIG. 5.

FIG. 7 is a hydraulic circuit diagram, showing the equipment and piping arrangement for the preferred execution. r

FIG. 8 is a hyd'aulic circuit diagram, showing the equipment and piping arrangcment for an alternative xecuton.

Refet'- now to FIGS. 1 to 6, with the understanding that only one side of the calender assembly has been illustrated and that the Components hereinafter described are duplicated for the side of the calender not shown.

-Lifting screw 10 is slidably mounted for vertical movement-in calender' vertical frame 11 and is threaded over 'a large proportion .of its length. Lifting screw 18 may be lifted or lowered by means of screwjack 12, which 'is coupled to lifting screw 10 by means of coupling 13 and operated by drive means 14. The output screw 15 of screwjack`12 is keyed for non-rotation. Crossshaft 16' transmits synchronized Operating torque to the screwjack (not shown) on the other side of the calender. By this means, the lifting and lowering motions of lifting screws 16' oneach side of the calender, aresynchronized. Liftng screw 1% is slidably jonrnaled at itsupper end in bushing 17, which is positioned in the upper part of the calender vertical frame 11.

Pivot arms 18 are pivotally mounted on calender vertical frame 11 by means of pivot pins 19 and mounting brackets 29. calender rolls 21 are journaled in bearings and housings 22, which are rigidly attached to flanges 23 of pivot arms 18.

The clevis-ends 24 of pivot arms 13, extend alternately to positions on either side of lifting screw 10. FIG. 3 shows alternate pivot arms 25. Fluid cylinders 26 are attached at their red-ends to clevis-ends 24 of pivot arms 18 and 25, and at their head-ends to positioning brackets 27. Positioning brackets 27 are mounted on liting screw 16 and are threaded internally to correspond with the thread on liiting screw IG. Positioning brackets 27 are assembled to position fluid cylinders 26 alternately on either side of lifting screw 10, and are locked in position by locknuts 28.

In accordance with the above arrangement when fluid pressure is applied to the head-ends of the pisto-ns within cylinders 26, downward forces are exerted on the clevisends 24 of pivot arms 13 and 25, which, through pivot pins 19, apply upward lifting forces to hearing housings 22. Similarly, fluid pressure applied to the rod-ends of the pistons within cylinders 26, applies downward forces to hearing housings 22. Spacers 29 maintain the relative positions between mounting brackets 20.

Calender base frames 30 (one on each side of the calender), support calender vertical frames 11 and carry screwjacks 12 and bearings and housings 31, which journal the bottom calender roll 32.

All connections to fluid cylinders 26 are located within the calender vertical frames 11, removable panels 33 providing access to the fluid connections and to` facilitate adjustrnent of positioning brackets 27, etc.

In the alternative arrangement shown in FIG. 5 and 6, the pivot arm is in two parte, lever arm 34 and mounting arm 35. The turning moment exerted by lever arm 34 on mounting arm 35, is transmitted through contacting surfaces 36.

Contacting surfaces 35 are unilateral abutments. Thus, although a lifting force may be ap'plied to hearing housings 22 by fluid cylinders 26, hearing housings 22 are free to move upwards under the influence of any external force, such as a wacl of paper passing through the nips, etc., without aecting the position of lever arm 34. i

To study the operation of this invention, refer now to FIGS. 1, 2, 3 and 7, which show-the mechanical arrangement and basic pressure fluid circuit diagram for the preferred execution.

To obtain relief of nip-pressures between calender rolls' V 21, fluid under pressure is applied to the head-ends of cylinders 26. This produces turning moments about pivot pins 19 and results in Upward lifting forces exerted on the rolls. To increase the nip-pressures between calender rolls 21, fluid under pressure is applied to the rod-ends of cylinders 26, which reverses the nip-relieving action and V provided for each roll, one at each end, and are controlled in parallel.

Nip-relief between calender rolls 21 is obtained by moving 4-way 3-position manual control valve41 to the left, which is the cross-over position. Fluid under` pressure enters pressure reducing valve 37, which is regulated to` give the required roll nip-relief using pressure gage 40 passes through manual control valve 41 and on tojthe head-end of cylinder 26. This produces a downward act-" corresponding roll 21 will also commence to lift.

ing force on piston 43 in cylinder 26, which results in an upward lifting force acting on roll 21.

Increased loading between calendar rolls 21 is obtained by moving 4-way 3-postion manual control valve 41 to the right, which is the straight-through position. Fluid under pressure enters pressure reducing valve 37, which is regulated to the required pressure using pressure gage 49, passes through manual control valve 41 and on to the rod-end of cylinder 26. This produces an upward lifting force on piston 43, which results in a downward acting force on roll 21.

Should an extra thick wad of paper pass through the nips during nip-loading, pressure fluid in the space beneath piston 43 in cylinder 26, will be suddenly increased. This increase in pressure will be immediately relieved through pressure relief valve 39 to tank 42. Pressure relief valve 39 is set to operate at a pressure consistent with component strength.

The preferred execution shown in FIGS. l, 2, 3 and 7, while designed primarily to enable the loading between the nips to be increased or decreased to suit ditfering conditions of Operations, this same execution can be used solely for increasing the nip loading or solely for decreasing the nip loading.

Refer now to FIGS. 5, 6 and 8, which show an alternative execution of this invention, in which fluid cylinders 26 are operable for relief of nip-pressures only.

Relief of nip-pressure between rolls 21 is obtained by moving 4-way 2-position manual control valve 44 downward, thus providing a through-path for the pressure fluid. Fluid under pressure enters pressure reducing valve 37, which is regulated to the required nip-relieving pressure using pressure gage 49, passes through manual control valve 44 and on to the head-end of cylinder 26. This produces a downward acting force on piston 43 in cylinder 26, and results in an upward lifting force on roll 21.

Refer now to FIG. 4, which is a schematic diagram showing the basic Operating sequence for roll lifting, as applied to both the preferred and alternative executions.

An essential feature of the roll lifting procedure is the fact that positioning brackets 27 are positioned on lifting screws 18 to provide progressively increasing distances, from the top roll position downwards, between pistons 43 within fluid cylinders 26 and the head-ends of fluid cylinders 26. These distances are shown as A in FIG. 4.

As lifting screws 10 are lowered by means of screwjacks 12, the fluid in the upper cylinders 26 is exhausted to tank 42 and the pistons bottom at the head-ends, forming solid links between pivot arms 18 and positioning brackets 27. Thus, further lowering of lifting screws 10 produces lifting of the upper roll 21. As the lowering progresses still further, pistons 43 in the cylinders 26 next down from the top, will bottom," and the It is thus seen that the progressively increasing distances between the pistons 43 and the head-ends of cylinders 26, result in successive lifting of the rolls and produce the required gaps between the rolls when lifted, as shown at D' in FIG. 4.

This method of roll lifting can also be used to reduce the number of active nips in the stack, by lowering lifting screws I'll, lifting the rolls and separating the nips, until the desired number of rolls remain in contact.

From the preceding description, it is seen that rolls may be simply removed from the stack without the need for disconnecting and removing links or lifting mechanisms from the hearing housings. At the same time, roll removal is facilitated by the fact that no roll lifting equipment is located above the roll stack.

A further feature of this invention is the fact that the combination of the mechanisms for roll lifting, niprelieving and nip-loading into one set of Components, which is totally enclosed in the vertical calender frame,

enables all pipings and connections to be located within the enclosed frame. This provides an unobstructed and compact assembly resulting in increased operator elficiency and, at the same time, the enclosed system and piping arrangements are protected from damage and kept free of accumulated dirt.

What I claim is:

1. A roll stack calender including vertically movable shafts, means for raising and lowering said shafts, valve controlled fluid pressure actuated nip-pressure regulating roll supporting means connected between said shafts and one or more of the calender rolls located above the bottom or king roll, said nip-pressure regulating means being operable independently of said shafts to apply upward pressure to the connected roll to decrease the load or nippressure at the nip between said roll and the next lower roll and being also operable independently of said vertically movable shatts to apply downward pressure to the connected roll to increase the load or nip-pressure at said nip, said calender being further characterized in that downward movement of said shafts results in upward movenment of all the calender rolls connected to said shafts through the agency of said nip-pressure regulating roll supporting means.

2. A roll stack calender including intermediately pivoted lever arms carrying calender rolls at one end thereof and having their other ends directly connected to vertically movable shafts through cylinder and p-iston devices, said cylinder and piston devices constituting fluid pressure actuated valve controlled nip-pressure regulating means operable independently of said shafts to apply upward pressure to the connected roll to decrease the load or nippressure at the nip between said roll and the next lower roll and being also operable independently of said movable shafts to apply downward pressure to the connected roll to increase the load or nip-pressure at said nip, and means for lowering and raising said shafts, said calender being further characterized in that downward movement of said shafts results in upward movement of all the calender rolls connected to said shafts through the agency of said nip-pressure regulating roll supporting means.

3. A roll stack calender including vertically movable shafts, means for raising and lowerng said shafts, valve controlled fluid pressure actuated nip-pressure regulating roll supporting means connected between said shafts and one or more of the calender rolls located above the bottom or king roll, said nip-pressure regulating roll supporting means including intermediately pivoted lever arms mounted in pairs, each of said pairs .of lever arms having a calender roll mounted between the ends thereof on one side of their intermediate pivots and a connection to the vertically movable shats from the remaining ends of said lever arms said connection comprising fluid pressure responsive cylinder and piston devices, the pistons of said devices being connected to said remaining ends of said leverarms and the cylinders of said devices being connected to said vertically movable shafts, the cylinder and piston devices of said nip-pressure regulating means being operable independently of said shafts to apply up- Ward pressure to the connected roll to decrease the load or nip-pressure at the nip between said roll and the next lower roll and being also operable independently of said vertically movable shafts to apply downward pressure to the connected roll to increase the load or nip-pressure at said nip, said calender being further characterized in that downward movement of said shafts results in upward movement of all the calender rolls connected to said shafts through the agency of said cylinder and piston devices.

4. A roll stack calender including vertcally movable shafts, means for raising and lower-ing said shafts, valve controlled fluid pressureactuated nip-pressure regulating roll supporting means connected between said shafts and one or more of the calender rolls located above the bottom or king roll, said nip-pressure regulating roll sup- 'co-Operating 'pai 1s, each of said lever arni assemblies comprising two lever arm sections having adjacent ends thereof pivotlly mounted on a common pivot and extendng outwardly from said common pivot in opposing directions, the outer ends of similar lever arm sections in each of said pairs of lever arm assemblies being connected to said vertically movable shafts and the outer cnds of the other lever arm sections in said pairs supporting the ends of said calender roll, said adiacent ends of said lever arm sections in each of said lever arm assemblies having co acting horizontal stop faces such that downward pressure on the ends of said level' arm sections connected to said shafts produces Upward pressure on the ends of said levet' .arm sections supporting the ends of said calender roll,

Whilst at the same time leaving said calender roll free to move upwardly when any lumps of paper stock or like objects pass through the nip between said calender roll and the next lower calender roll in said stack, said calender being further characterized in that downward movement of said shafts results in an Upward movement of all the calender rolls connected to said shafts through the agency of said nip-pressure regulating roll supporting means.

5. A roll stack calender as set forth in claim 4 in which the connection between the outer ends of similar lever arm sections and said shafts comprises fluid pressure responsive cylinder and pisten devices, the istons of said devices being connected to the outer ends of said similar lever arm sections and the cylinders of said devices being connected to said shafts.

6. A roll stack calender as set fo'th in claim 4 including a calender frame and in which each of said lever arm assemblies is internediately pivoted on said calender frame.

References cited' in the file of this patent UNITED STATES PATENTS 1,934,233 Malkin Nov. 7, 1933 2,300,994 Thiele et al Nov. 3, 1942 2,8SO,952 Hornbostel Sept. 9, 1958 2,98S,1G0 Hornbostel May 23, 1961 2,992,866 Cavalieri July 18, 1961 FOREIGN PATENTS 523,866 Germany Api'. 29, 1931 794531 France Dec. 12, 1935 %08,317 Germany July 12, 1951 1,054,953 Germany Apr. 16, 1959

Claims (1)

1. A ROLL STACK CALENDER INCLUDING VERTICALLY MOVABLE SHAFTS, MEANS FOR RAISING AND LOWERING SAID SHAFTS, VALVE CONTROLLED FLUID PRESSURE ACTUATED NIP-PRESSURE REGULATING ROLL SUPPORTING MEANS CONNECTED BETWEEN SAID SHAFTS AND ONE OR MORE OF THE CALENDER ROLLS LOCATED ABOVE THE BOTTOM OR KING ROLL, SAID NIP-PRESSURE REGULATING MEANS BEING OPERABLE INDEPENDENTLY OF SAID SHAFTS TO APPLY UPWARD PRESSURE TO THE CONNECTED ROLL TO DECREASE THE LOAD OR NIPPRESSURE AT THE NIP BETWEEN SAID ROLL AND THE NEXT LOWER ROLL AND BEING ALSO OPERABLE INDEPENDENTLY OF SAID VERTICALLY MOVABLE SHAFTS TO APPLY DOWNWARD PRESSURE TO THE CONNECTED ROLL TO INCREASE THE LOAD OR NIP-PRESSURE AT SAID NIP, SAID CALENDER BEING FURTHER CHARACTERIZED IN THAT DOWNWARD MOVEMENT OF SAID SHAFTS RESULTS IN UPWARD MOVEMENT OF ALL THE CALENDER ROLLS CONNECTED TO SAID SHAFTS THROUGH THE AGENCY OF SAID NIP-PRESSURE REGULATING ROLL SUPPORTING MEANS.

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