Abstract:
A take-out leading roll, spreader roll or equivalent for a web-like material including a non-revolving roll axle having end parts and a middle part situated between the end parts, and a continuous and tubular roll mantle revolvingly journalled by bearings on the roll axle and extending over the end parts and the middle part. The middle part is pivotally linked to the end parts to enable the roll to be bent to a desired arcuate shape. The roll mantle is preferably journalled on the roll axle only in the areas of the roll ends by bearings supported on the end parts of the roll axle. The material of the roll mantle is preferably a composite material.

Description:
FIELD OF THE INVENTION 
     The invention concerns a take-out leading roll, spreader roll, or equivalent for a web-like material, which roll comprises a non-revolving roll axle and a roll mantle journalled revolvingly by means of bearings on said roll axle, and which roll can be bent to the shape of the desired arc. 
     BACKGROUND OF THE INVENTION 
     Take-out leading rolls and spreader rolls have been formed most commonly so that they have a continuous axle and a roll mantle fitted on the axle, which roll mantle is again composed of a number of parts. The take-out leading roll can be made to be curved to the desired shape by shifting the outer journalling points of the roll mantle in the radial direction, in which connection the mantle forms an arc or a broken line. As a rule, each of the mantle parts is journalled separately on the axle, in which case the arrangement comprises a number of bearings. The conventional solutions involve a number of problems and drawbacks, which are, among other things, problems of journalling of the roll and peaks of heat produced by the journalling in the paper web. The making of the mantle of a number of parts may also constitute a considerable problem, because the gaps between the parts may mark the paper web and because the arc form of the roll is not optimal, but the line of shape of the roll is shaped as a broken line. Further, owing to the metallic roll mantle, problems of corrosion may arise. One such prior-art spreader roll is described, for example, in the U.S. Pat. No. 4,692,971. Attempts have been made to provide an improvement over such a prior-art spreader roll, for example, so that a coating layer of a resilient material has been fitted onto the metal mantle consisting of a number of parts, the objective of this arrangement being in particular to provide an improvement concerning the problem of marking of the paper web and concerning optimization of the arc form of the roll. However, the journalling system of the roll is similar to that described above, and, thus, also the problems related to the journalling are unchanged. Such a spreader roll is described, for example, in the Canadian Patent No. 766,843. 
     Earlier, attempts have been made to find a solution for the problem arising from a roll mantle consisting of a number of parts also so that, as the roll mantle, a continuous metal tube mantle has been used which has been provided with “cuts”, i.e. into which slots have been formed in order to facilitate the bending of the roll mantle. This construction, however, causes its own problems, one remarkable one of said problems being the fact that, owing to its construction, the roll mantle becomes quite slack, i.e. excessively readily bending. In such a case, the roll mantle concerned must be supported on the roll axle by means of bearings at a number of points, for which reason the problems described above and arising from the journalling remain unchanged. Also, the cost of manufacture of the roll mantle is relatively high because of the mode of manufacture. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a novel construction of a take-out leading roll, spreader roll or equivalent, by whose means the problems related to the prior art described above are avoided. In view of achieving the objectives of the invention, the invention is mainly characterized in that the roll mantle is a continuous, tubular mantle, and that the roll axle consists of three parts linked with one another, i.e. of two end parts and of a middle part, which are pivotal in relation to one another for the purpose of bending the roll mantle. 
     By means of the invention, quite a considerable advantage is achieved over the prior art, and of the advantages obtainable by means of the invention, for example, the following should be stated. Owing to the construction in accordance with the invention, in the roll it is possible to use a mantle consisting of one part. As the material of the mantle, it is favourably possible to use a composite material, in which case the lowest natural frequencies of the roll can be raised to such a high level that a roll mantle supported exclusively at the ends can be used as the construction. In such a case the problems of heat arising from journalling, related to the prior art, can be avoided. When a fully continuous roll mantle with no gaps is used, all problems of marking of the paper web can also be avoided. When a composite material is used as the material of the roll mantle, all problems of corrosion can also be avoided. The further advantages and characteristic features of the invention come out from the following detailed description of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, the invention will be described by way of example with reference to the figures in the accompanying drawing. 
     FIG. 1 is a fully schematic sectional view of a roll in accordance with the invention, in particular illustrating the mechanism of bending of the roll. 
     FIG. 2 is a more detailed illustration of the mechanism of bending of the roll as shown in FIG.  1 . 
     FIG. 3 is an illustration corresponding to FIG. 2 of an alternative construction of the mechanism of bending. 
     FIG. 4 is an illustration corresponding to FIGS. 2 and 3 of a further alternative embodiment of the mechanism of bending. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 1 the roll is denoted generally with the reference numeral  10 . The roll  10  comprises a roll mantle  11 , which is fitted to revolve on a non-revolving axle  12   a,    12   b.  The roll axle consists of three parts, i.e. the end parts  12   a  and the middle part  12   b.  In the end areas of the roll  10 , support sleeves  13  have been fitted, on which the roll mantle  11  itself is again mounted. Thus, the roll mantle  11  is journalled on the axle  12   a,    12   b  through said support sleeves  13  by means of bearings  14 , 15 , which form a pair of bearings and which have been mounted, in the way illustrated in FIG. 1, at an axial distance from one another. The roll mantle  11  is continuous and extends from end to end in the roll. In FIG. 1, the mechanism of bending of the roll is denoted generally with the reference numeral  20 , and different alternative embodiments of said mechanism of bending are described in more detail in relation to FIGS. 2 to  4 . 
     FIG. 2 shows a first embodiment of the mechanism  20  of bending of the roll, which corresponds to the illustration of FIG. 1 on a larger scale. Thus, FIG. 2 illustrates one end area of the roll  10 , but it is understood that the opposite end of the roll comprises a fully similar construction. As came out in the description above, the axle of the roll  10  consists of three parts, i.e. of an end part  12   a  placed in each end area of the roll and of a middle part  12   b  interconnecting these end parts. Further, referring to the description above, in the end areas of the roll, support sleeves  13  have been fitted, which have been mounted revolvingly on the end parts  12   a  of the axle by means of pairs of bearings, i.e. the bearings  14 , 15 . The roll mantle  11  has been fitted on the support sleeves  13  so that the bearings  14 , 15  alone take care of the journalling of the roll mantle  11  without necessity of using bearings in the middle area of the roll at all. The end parts  12   a  of the axle extend, in the axial direction of the pair of bearings, from the inner bearings  15  a certain distance in the axial direction into the roll, and the middle part  12   b  of the axle is a tubular piece, in the way illustrated in the figures, into whose interior the parts of the end parts  12   a  of the axle that extend inwards axially from the inner bearings  15  of the pair of bearings penetrate. The end parts  12   a  and the middle part  12   b  are interconnected by means of an articulated joint member  25 , which prevents the end parts  12   a  and the middle part  12   b  from moving in relation to one another in the radial direction, but which permits an inclining of said end parts and the middle part in relation to one another in the axial direction of the roll. The inner diameter of the tubular middle part  12   b  of the axle is substantially larger than the outer diameter of the end parts  12   a,  so that said inclining of the end parts  12   a  and the middle part  12   b  in relation to one another around the articulated joint member  25  is permitted. The end parts  12   a  of the axle are also hollow, tubular pieces, into whose interior the parts of the mechanism of bending of the roll have been fitted. 
     In the exemplifying embodiment of FIG. 2, the bending mechanism  20  comprises a cam member  21 , which is mounted pivotally in the wall  12   a′  of the tubular end part by means of an articulation pin  22  placed in the cross direction of the roll so that, in relation to said articulation pin  22 , the cam member  21  forms a two-arm lever, whose inner end penetrates into the interior of the tubular end part  12   a  and whose outer end extends through the wall  12   a′  of said tubular end part to outside the end art and rests against the inner face  12   b′  of the middle part  12   b.  Further, in the interior of the tubular end part  12   a,  a regulation rod  23  is fitted, which is displaceable in the axial direction and which is supported against the wall  12   a′  of the tubular end part so that the regulation rod  23  is placed centrally inside the end part  12   a.  The inner end of the regulation rod  23  is supported against the cam member  21 . The regulation rod  23  is provided, for example, with screw means or equivalent members (not shown) so that, when the regulation rod  23  is rotated, it can be shifted precisely in the axial direction of the roll into the desired position. In FIG. 2, the regulation mechanism  20  is shown in the neutral position, i.e. in a position in which the roll is not bent. Further, in the illustration in FIG. 2, the cam member  21  rests. against the inner face  12   b′  of the middle part of the axle. This is, however, not fully indispensable in view of the operation, for in said neutral position there may be a little gap between the cam member  21  and the inner face  12   b′  of the middle part. The cam member  21  is shaped so that, when the regulation rod  23  starts being shifted in the axial direction, for example by rotating, inwards in the roll, the regulation rod  23 , at the same time, pivots the cam member  21  around the articulation pin  22 , in which connection, as the cam member  21  pivots, it is supported with a greater force against the inner face  12   b′  of the middle part  12   b  of the axle while at the same time increasing the distance between the end part  12   a  and the middle part  12   b  of the axle at the side of the cam member  21 . In this connection the axle bends. 
     FIG. 3 shows an alternative embodiment of the mechanism of regulation of bending of the roll. In FIG. 3, the regulation mechanism is denoted with the reference  20 A. The end area of the roll is in the other respects identical with that described in relation to FIG. 2, so that, in the following, the construction shown in FIG. 3 will be described in respect of the regulation mechanism only. In the embodiment of FIG. 3, the regulation mechanism  20 A is hydraulically operated. In the axial direction, the inner end of the end part  12   a  of the axle is closed by means of a wall  22 A, and a piston  24 A has been fitted inside the tubular end part  12   a  so that said piston  24 A and the end  22 A define a cylinder space  26 A between them. The cylinder space  26 A is filled with a pressure medium, for example hydraulic fluid. The piston  24 A is connected with a rod  23 A, which penetrates axially out through the roll end. In the exemplifying embodiment shown in FIG. 3, a screw member  27 A is fitted in the end part  12   a  of the axle, by means of which screw member  27 A the rod  23 A and, thus, the piston  24 A can be regulated and shifted in the axial direction of the roll. When the piston  24 A is shifted in the axial direction, the volume of the cylinder space  26 A can be changed. At the cylinder space  26 A, in the wall  12   a′  of the tubular end part, a piston member  21 A has been fitted, which penetrates radially through said wall  12 ′, which rests against the inner wall  12   b′  of the middle part  12   b  of the roll axle, and upon which piston member  21 A the pressure in the cylinder space  26 A can act. In this connection, when the volume of the cylinder space  26 A is reduced by means of the piston  24 A, the pressure is increased in said cylinder space  26 A and shifts the piston member  21 A in the radial direction outwards with a greater force against the inner wall  12   b′  of the middle part of the axle. In such a case, the axle and, thus, the whole roll  10  can be bent in the desired way. 
     Finally, in FIG. 4, a further alternative solution of the bending mechanism of the roll is illustrated, which mechanism is denoted with the reference  20 B in FIG.  4 . FIG. 4 differs from the illustrations in FIGS. 2 and 3 exclusively in respect of the bending mechanism  20 B, and in the other respects, in this figure, the same reference denotations have been used as in said FIGS. 2 and 3. In the embodiment that is being described now, the bending mechanism  20 B consists of a regulation rod  23 B, which has been fitted axially inside the tubular end part  12   a  of the roll axle. In the axial direction, at the outer end of the regulation rod  23 B, a screw member  27 B or an equivalent device is fitted, by whose means the regulation rod  23 B can be shifted and regulated in the axial direction. To the opposite end of the regulation rod  23 B, i.e. to the inner end in the axial direction, an oblique, wedge-shaped face  24 B has been formed. Further, to the inner end of the end part  12   a  of the roll axle, a radially extending and moving wedge piece  21 B has been fitted, which is supported against the inner face  12   b′  of the middle part  12   b  of the roll axle, on one hand, and against the wedge-shaped face  24 B of the regulation rod  23 B, on the other hand. At the side of the regulation rod  23 B opposite in relation to the wedge piece  21 B, a support  22 B has been fitted inside the tubular end part  12   a,  on which support  22 B the regulation rod  23 B rests. In such a case, when the regulation rod  23 B is shifted in the axial direction, the wedge piece  21 B can be made to move in the radial direction so that, when the regulation rod  23 B is shifted axially inwards in the roll, the wedge piece  21 B moves radially outwards and rests with a greater force against the inner face  12   b′  of the middle part  12   b  of the roll axle. By means of this arrangement, the roll axle and, thus, the whole roll can be bent in the desired way. 
     Owing to the embodiments described above of the bending mechanism of the roll  10 , the bearing arrangements can be eliminated in the roll completely from under the paper web, in which case the heat arising from the bearings does not cause a marking in the paper web. The bearings can be fitted exclusively in the end areas in the roll, in which case their lubrication and cooling can be arranged easily. Further, it is significant from the point of view of the invention that, owing to its bending mechanism, the roll  10  retains its curved form even if it had been removed from the machine. By means of the novel construction, it is possible to use a roll mantle  11  consisting of one part on the roll. Further, if constructions of different bend curve forms are desired, the mantle can be made of a composite material, in which connection, when the composite mantle is being manufactured, its rigidity can be varied readily by just changing the fibre angle. In this way, constructions with different rigidities in different locations of the roll can be obtained, whereby the bending curve of the roll can be shaped as desired. Moreover, in respect of its resistance to fatigue, composite is an excellent material. 
     Above, the invention has been described by way of example with reference to the figures in the accompanying drawing. The invention is, however, not confined exclusively to the exemplifying embodiments illustrated in the figures, but different embodiments of the invention may show variation within the scope of the inventive idea defined in the accompanying patent claims.