WO2003038187A1

WO2003038187A1 - Method for replacing an intermediate roller

Info

Publication number: WO2003038187A1
Application number: PCT/FI2002/000838
Authority: WO
Inventors: Markku Kirvesmäki; Aaron Mannio
Original assignee: Metso Paper, Inc.
Priority date: 2001-10-30
Filing date: 2002-10-29
Publication date: 2003-05-08
Also published as: DE10297366T5; FI111394B; FI20012096A0; FI20012096A

Abstract

The invention relates to a method for replacing an intermediate roller (4) in a set of multiple rollers (5) comprising an upper roller and a lower roller and at least two intermediate rollers (4) between these. In the method, the fixing means between the journal box of the first intermediate roller and the roller fixing means is released, the locking means (3) of the control means (1) of the axles (4; 42) of the first intermediate roller are released, the first intermediate roller is shifted through the passage (7; 71) of the control duct to the mouth openings (7; 72) of the control ducts, and then the first intermediate roller (4) is replaced with another intermediate roller. After this, the second intermediate roller is introduced in the set of rollers (5) by shifting the axles (4; 42) of the intermediate roller through the control duct (7) of the control means to its fixing point. The invention also relates to the control means used in the method.

Description

Method for replacing an intermediate roller

The invention relates to a method as defined for instance in the preamble of claim 1 for replacing an intermediate roller.

The invention also relates for instance to a control means as defined in the preamble of claim 4 for replacing an intermediate roller.

A set of multiple rollers frequently comprises up to 10-12 rollers, which are disposed on top of each other to form a substantially vertical staple of rollers, whose height may be up to 10 metres. The set of rollers includes an upper roller and a lower roller, and a varying number of intermediate rollers, one or more of which are usually polymer-coated. The rollers are disposed on top of each other in nip contact, with the fibre web passing through the roller nips. In currently used calenders with multiple rollers, the journal boxes of an intermediate roller are fixed to levers, which may be subjected to the desired torsional force by means of hydraulic cylin- ders or similar actuators fixed to them. The levers used for compensating the intermediate roller mass are articulated in the frame of the set of rollers (calender).

New methods for replacing intermediate rollers in a set of rollers have been developed, the most frequently implemented among these being probably the use of separate lifting bushings. Such bushings are disclosed i.a. in DE Utility Model 20,001,001, DE Patent Application 19,904,180 and DE Patent Application 19, 856,517. In use, one of the major problems of lifting bushings has been that, for replacing an intermediate roller, an operator is required at both ends of the intermediate roller in order to fit the lifting bushings onto the axles provided at the ends of the intermediate roller. If operators are required on the service bridge while the in- termediate roller is replaced, work safety will be poor, because there is always a risk of the intermediate roller dropping.

A lifting bushing is a lifting device between the lift hook and the roller. A lifting bushing suspended from a lift hook is pushed in parallel with the longitudinal axis of the roller so that the roller axle is inserted into the opening in the lifting bushing. The lifting bushing is mechanically locked in a groove in the roller axle to prevent the roller from sliding off. The lifting bushing thus forms a stiff structure together with the roller, so that the roller can be lifted on a lifting line located notably outside the roller configuration. This arrangement is necessary, because rollers located above the roller to be lifted and other calender structures form a bar to the selection of a lifting line at the roller.

For replacement of intermediate rollers of a set of rollers to be successful, one must avoid contact between the surfaces of hot thermo-rollers and polymer-coated inter- mediate rollers during the lifting, because polymer-coated intermediate rollers would then be exposed to damage on their surface.

In the extreme case, rollers placed on top of each other are spaced by only approx. 5 mm, so that the problem may even be serious if an intermediate roller is not evenly hoisted during the replacement operation. Intermediate rollers cannot be lifted di- rectly from their positions due to rollers located above. Rollers located above also make it impossible to bring an intermediate roller into position without accessory equipment.

The purpose of the invention is to eliminate the inconveniences of prior art. Thus, the first purpose of the invention is to provide a method and a means used in this for replacing an intermediate roller, with the intermediate roller being prevented from touching the rollers located above or underneath this particular roller at any stage of the replacement process. A second purpose of the invention is to prevent an intermediate roller from dropping during the roller replacement and to provide more safe roller replacement.

The invention relates to a method as defined for instance in claim 1 for replacing an intermediate roller in a set of multiple rollers.

The invention also relates to a control means as defined for instance in claim 4 for replacing an intermediate roller in a set of multiple rollers.

In the method of the invention, a set of multiple rollers comprises an upper roller and a lower roller, with at least two intermediate rollers between these. In the method, the fixing means between the journal box of the first intermediate roller and the roller fixing means are released and the locking means of the control means of the axles of the first intermediate roller are released. After this, the first intermediate roller is brought through the passage of the control duct to the mouth openings of the control ducts, after which the first intermediate roller is replaced with another intermediate roller. The second intermediate roller is brought into the set of rollers by shifting the intermediate roller axles through the control duct of the control means to its fixing point. In this context, we point out that the concepts of first intermediate roller and second intermediate roller do not refer to the order of the rollers in the set of rollers. The first intermediate roller implies any intermediate roller in the set of rollers, which is to be removed from the set of rollers for service, intermediate storage, transfers or for any other reason. The second intermediate roller, again, refers in this case to a roller that is new, repaired or the like, and which is intended to replace an intermediate roller that has been removed from the set of rollers.

The control means of the invention comprises a fork member for controlling the intermediate roller axle and a locking means for locking the intermediate roller axle in the fork member. The central line of the control duct of the control means passes at the same distance relative to the rollers located above and underneath the intermediate roller. The distance of the central line of the control duct from the rollers located above and underneath the intermediate roller is always greater than the diameter D of the cylindrical mantle portion of the intermediate roller.

With the use of the control means of the invention for replacing an intermediate roller, the intermediate roller will not at any stage of the replacement operation touch rollers located above or underneath this intermediate roller, because, as an intermediate roller is removed from the control means, its axles are moved through the control duct of its control means while the intermediate roller is between the rollers. The distance of the central line P of the control duct of a given intermediate roller from the central lines of the control ducts of intermediate rollers located higher or lower than this intermediate roller will always be greater than the diameter D of the cylindrical mantle portion of the intermediate rollers. Thus, the control duct formed between the upper and lower prongs of the fork member of the control means will prevent the intermediate roller from moving excessively in the up-down direction during the replacement process.

The fork member of the control means of the intermediate roller comprises a locking means, which prevents the roller from dropping from the fork member in an error situation, such as for instance, when the fixing screws of the roller have been re- leased and there are still people in the risk zone (while unscrewing the fixing screws of the roller, mechanics have to operate on a platform in the dropping line of the roller).

Among additional benefits gained with the invention, we note that the mechanism for releasing the locking means of the control means can be provided with a very straightforward embodiment; the bolt means of all of the intermediate rollers in the set of rollers can be released simultaneously, since only one intermediate roller at a time is replaced, the fixing screws between the other intermediate rollers and their roller fixing means being still tightened, so that the remaining intermediate rollers cannot move by mistake. The central line of the control duct is advantageously di- rected downwardly from the plane of the roller fixing point on the control means. When removed, the intermediate roller will then slide downwardly in the passage in the control duct, facilitating the removal of the intermediate roller from the set of rollers.

The invention is described below in further detail with reference to the accompany- ing drawings.

Figure 1A shows an intermediate roller viewed perpendicularly to the end, with the fixing screws of the journal box of the intermediate roller and the lever released.

Figure IB shows the intermediate roller of figure 1 moved to the mouth of the fork member of the control means.

Figure 2 shows the lower roller of a set of multiple rollers and two intermediate rollers on top of this, viewed perpendicularly to the end of the set of rollers.

Figures 1 A and IB show an intermediate roller 4 equipped with the control means 1 of the invention including its axles 42, viewed perpendicularly to the intermediate roller end. The control means structure will be studied below with reference to fig- ure 1A.

The control means 1 has a fork member 2 and a locking i.e. bolt means 3 in locking position. The fork member 2 comprises an elongated upper prong 21. The rear part 21a of the upper prong 21 is slightly tapered, whereas its front part 21b is strongly tapered in the direction away from the roller fixing point on the upper prong. The elongated lower prong 22 has a mirror- like design relative to the upper prong; its rear part 22a is slightly tapered, whereas the front part 21b is strongly tapered. Between the rear parts 21a, 22a of the upper and lower prong, a housing 23 connecting the prongs is provided, which is curved in shape and in which the radius of curvature of the inner surface roughly matches the radius of curvature of the roller axle 4; 42. Thus a control duct 7 is formed between the upper and lower prong of the fork member 2 for the control of the movements of the roller axle 42. In the passage 7; 71 of the control duct facing the fork member housing 23, the diameter d of the control duct 7 is of the same order as the diameter of the roller axle 4; 4. The diameter d; dl of the passage 7; 71 increases slightly in the direction towards the front part of the fork member prongs, because the rear part of the lower and upper prongs taper gradually, with the distance of the inner surfaces of the rear part from the central line P of the fork member increasing gradually. The front parts 2; 21b, 22b of the upper and lower prongs taper strongly, so that the distance of their inner surfaces from the central line P of the fork member increases strongly, a largely open mouth part 72 of the control duct 7 being formed between the front parts of the upper and lower prongs. The central line P passes at the same distance from the upper and the lower prongs 21, 22 of the fork member 2, forming at the same time the central line of the control duct 7. The central line is directed downwardly on the control means from the plane defined by the roller fixing point, as can be better seen in figure 2.

The central line P of the fork member 2 controlling the intermediate roller axles and at the same time that of the passage 7; 71 is in a direction such that the intermediate roller mantle will not touch the mantles of rollers located above and underneath the intermediate roller when the intermediate roller is removed from the set of rollers or is returned in position in the set of rollers.

The control means 1 is fixed to the end of a lever 6 used to compensate the mass of the intermediate roller. The control means 1 comprises the fork member 2 described above and the locking i.e. bolt means 3. The bolt means 3 comprises a bolt member 32 and a press means 33 actuating the bolt member. The frame 32; 32a of the bolt member is pivotally fixed by its joint 32; 32b to a two-part axle 31. The press means 33 has a helical spring 33b and a pneumatic cylinder 33a, which can be supplied with compressed air. The first straight part 31a of the two-part axle 31, which faces the pneumatic cylinder, touches the helical spring 33; 33b. The second part 31b of the axle 31 facing the bolt member is articulated in the first part 31a of the axle facing the pneumatic cylinder, and the bolt member frame 32; 32a, again, is fixed by articulation to its end. The spring force 33; 33b of the helical spring maintains the bolt member 32 in locking position, i.e. inserted into the control duct 7, even if basic air pressure had been conducted into the pneumatic cylinder 33; 33a.

In the situation shown in figure 1 A, the fixing screws between the journal box of the axle 4; 42 (not shown in the figure) and the lever 6 are released, and the bolt means 3 is thus in locking position, where the bolt member 32 is inserted into the passage 7; 71 in the control duct. The locking, i.e. the bolt means 3 in its locking position prevents movement of the intermediate roller axles 4; 42 in the passages 7; 71 of the fork members 2, so that the intermediate roller 4 cannot drop from the fork member 2 of the control means. Figure 1A also shows the resultant force F exerted by the roll axle 4;42 on the inner surface of the lower prong 2; 22 as the axle strives to move towards the mouth opening 72 of the passage 7. The location of the articulation point (fixing point) of the bolt member 32 of the bolt means 3 at the end of the second part 31 ; 31b of the two-part axle is disposed such that the direction of the resultant force F passes in the vicinity of the fixing point of the bolt member. Then the resultant force F will press the frame 32; 32a of the bolt member inwardly, should the axle 4; 42 of the intermediate roller be allowed to move in the fork member before the bolt means is released, which, again, would result in additional locking of the locking means. This ensures that the intermediate roller axle is not allowed to pass by the locking means, even if it would move in the passage of the fork member after the fixing screws have been released.

Figure IB shows the same intermediate roller control means as figure 1, but with its bolt means 3 released. The bolt means 3 has been released by feeding air into the pneumatic cylinder 33a of the pressure means 33, generating compression of the helical spring 33b. While compressing, the helical spring 33b propels the first part 31a of the two-part axle 31, causing simultaneously the bolt member frame 32; 32a fixed by articulation to the end of the second part 31b of the two-part axle to swing inside the rear part of the lower prong.

The bolt means of all of the intermediate rollers in the set of rollers can be released simultaneously, since one single intermediate roller is replaced at a time. The fixing screws of the remaining intermediate rollers remain tightened, and are thus not al- lowed to shift by mistake. Such a mechanism for releasing the bolt means of intermediate rollers notably simplifies the way of regulating the supply of compressed air into the control means, compared to the case where each bolt means is equipped with an individual control of compressed air supply. The supply of compressed air in order to release the bolt members of the bolt means can be safely performed un- der remote control, e.g. by remote radio control, in situations where there are no people in the vicinity of the set of rollers.

With the bolt means 3 of the intermediate roller 4 in released position, the axles 4; 42 of the intermediate roller can be freely moved in control duct passages 7;71 be- tween the fork member prongs to the mouth openings 7; 72 of the control ducts, by means of bushings fixed to the axles at the ends of the intermediate roller, for instance (not shown in the figure). The passage 7; 71 is inclined downwardly from the axle fixing point on the control means, the roller sliding by force of gravity to the mouth opening 7; 72 of the control duct. When the intermediate roller axles have reached the mouth openings of the control ducts, the intermediate roller can be replaced by another intermediate roller.

When a second intermediate roller is introduced in the set of rollers, the bolt means is maintained in locking position by interrupting the air supply to the pneumatic cylinder. The intermediate roller axles 4; 42 are inserted through the control duct passages 7; 71 to their fixing point on the control means, the intermediate roller axles thus releasing the bolt members 3; 32 of the bolt means by pushing. When the axles provided at the ends of the intermediate roller have passed by the bolt members 3; 32 of the bolt means, they close automatically, thus preventing the intermediate roller from returning towards the mouth opening of the control duct.

Figure 2 illustrates the disposition of intermediate rollers equipped with the control means 1 of the invention in a calender consisting of a set of multiple rollers 5.

Figure 2 shows the lowermost roller in a set of multiple rollers and three intermediate rollers located above this. The rollers of the set of rollers 5 have been disposed on top of each other to form a substantially vertical staple of rollers. The lowermost intermediate roller 4; 4' and the uppermost intermediate roller 4; 4"' are polymer- coated, whereas the central intermediate roller 4; 4" is a heated roller. The figure shows the orientation of the central lines P; P', P" of the control ducts of the control means 1 ; 1 ' and 1 ; 1 " and 1 ; 1 '" of the intermediate rollers such that, during the process of replacing intermediate rollers, the mantles of successive intermediate rollers do not get into mutual contact even by mistake. The distance S of the central line P of a given intermediate roller to the central line of intermediate rollers located above and underneath this particular intermediate roller will then always be larger than the diameter D of the cylindrical mantle portion of the intermediate rollers.

Merely one embodiment of the invention has been described above, and it is obvi- ous to those skilled in the art that the invention can be implemented in many other ways as well without departing from the inventive idea defined in the claims.

Claims

1. A method for replacing an intermediate roller (4) in a set of multiple rollers (5) comprising an upper roller and a lower roller and at least two intermediate rollers (4) between these, characterised in

- releasing the fixing means between the journal box of the first intermediate roller and the roller fixing means (6),

- releasing the locking means (3) of the control means (1) of the axles (4; 42) of the first intermediate roller,

- shifting the first intermediate roller through the control duct passage (7; 71) to the mouth openings (7; 72) of the control duct, and then replacing the first intermediate roller (4) by another intermediate roller,

- introducing the second intermediate roller in the set of rollers (5) by moving the axles (4; 42) of the intermediate roller through the control duct (7) of the control means to its fixing point.

2. A method as defined in claim 1, characterised in that, as the second intermediate roller is returned to the set of rollers (5), the locking means (3) is in its locking position, and when the axles (4; 42) of the intermediate roller have reached their fixing point on the control means (1), the locking means (3) is locked.

3. A method as defined in claim 1 or 2, characterised in that the first intermediate roller (4) is moved through the passage (7; 71) of the control duct by being allowed to slide downwardly in the passage by force of gravity or by being shifted with a lifting device.

4. A control means (1) for replacing an intermediate roller (4) in a set of multiple rollers (5) comprising an upper roller and a lower roller and at least two intermedi- ate rollers (4) between these, characterised in that each control means (1) comprises

- a fork member (2) for controlling the axle (4; 42) of the intermediate roller,

- a locking means (3) for locking the axle (4; 42) of the intermediate roller to the fork member.

5. A control means (1) as defined in claim 4, characterised in that the fork member comprises upper and lower prongs (2; 21, 22), between which the control duct (7) is formed.

6. A control means (1) as defined in claim 5, characterised in that the central line (P) of the control duct (7) passes at the same distance relative to the rollers located above and underneath the intermediate roller.

7. A control means (1) as defined in claim 6, characterised in that the distance of the central line (P) of the control duct from the rollers located above and underneath the intermediate roller is always larger than the diameter D of the cylindrical mantle portion of the intermediate roller.

8. A control means (1) as defined in claim 6, characterised in that the central line (P) is directed downwardly from the plane of the roller fixing point on the control means (2).

9. A control means (8) as defined in any of claims 4-6, characterised in that the locking means (3) of all of the intermediate rollers can be released/closed simultaneously.

10. A control means (8) as defined in any of claims 4-9, characterised in that the locking means (3) of the control means can be released/opened by a pneumatic cylinder (3; 33).