Abstract:
A segmented roll has a plurality of end-to-end mounted roll segments ( 10, 10′ ), each adapted to rotate on bearings supported on a separate support shaft ( 11 ). In both axial end surfaces of the support shafts ( 11 ) of the roll segments ( 10 ) there are coupling means such as an annular projection and an annular recess serving to disengageably connect two adjacent roll segments ( 10 ) to each other. The support shaft ( 11 ) has at least two parts ( 16, 18 ) whose mutual disposition is made alterable for the purpose of altering the axial length of the support shaft ( 11 ) so much that the coupling means ( 29, 41 ) of the facing axial ends of two adjacent roll segments ( 10 ) can be engaged and disengaged with each other. This arrangement makes it possible to change a single roll segment from the central area of the segmented roll without the need for disassembling the entire row of roll segments.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     This application is a continuation of PCT application No. PCT/FI00/00230, filed Mar. 21, 2000, and claims priority on Finnish Application No. 990633, filed Mar. 22, 1999, the disclosures of both of which applications are incorporated by reference herein. 
    
    
     STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a segmented roll comprised of a plurality of end-to-end mounted roll segments, each adapted to rotate on bearings supported on a separate support shaft. 
     When desired, the bow of such a segmented roll can be changed by adjusting the position and/or distance of the support points of the individual roll segments in regard to their mounting frame, thus making the roll extremely suitable for use, e.g., as a spreader roll in conjunction with the handling of a web-like continuous sheet of material. The segmented roll is also suited for use, e.g., as a guide roll for a paper web or as a pressure roll in winding. 
     In conventional segmented roll constructions, each of the roll segments is generally journaled at its both ends on bearings which are supported on the segmented roll mounting frame or similar support framework. Frequently, two adjacent roll segments share one bearing unit. Then, removal of one roll segment from the central area of this kind of segmented roll may be difficult, because the segmented roll must be disassembled starting from one end in order to reach the roll segment to be replaced at the central area of the segmented roll. 
     From FI laid-open publication no. 62514 is known a spreader roll of the above-described type, wherein the respective abutting stub shafts of adjacent roll segments are adapted to be supported on a two-part support bearing block that determines the roll bow. Thus, each stub shaft is provided with a separate support bearing that is designed to function as a pivotal bearing point. The pivotal bearing points of the abutting stub shafts are adapted in close proximity to each other on the different sides of the support bearing, whereby each support bearing unit supports one of the adjacent pivotal bearing points. This kind of a two-part support bearing block makes it possible to dismount and replace separate roll segments without the need for complete disassembly of the entire spreader roll. On the other hand, such an arrangement places two bowing points at a small distance from each other thus causing nonuniform bowing of the roll. As the bowing point is not exactly at the mating point of the abutting roll segments, but rather, displaced by a small distance therefrom, the bend of the roll tends to lift up the end of the roll segment and thus makes the roll rotate bowed into a toothed shape. Hence, the correct geometry of roll bow is not attained which causes problems in controlling the web travel. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a novel type of segmented roll in which all separate roll segments are dismountable and replaceable without the need for complete disassembly of the entire segmented roll and which segmented roll is capable of assuming a smooth bow. 
     The segmented roll according to the invention has coupling means adapted to both axial end surfaces of the support shafts of its roll segments, said coupling means serving to disengageably connect two adjacent roll segments to each other. The support shaft contains at least two parts such that changing the mutual disposition of said parts makes it possible to alter the axial length of the support shaft. 
     Advantageously, the coupling means on the support shaft end surfaces are such that allow a coupling to be established between two adjacent roll segments, the coupling being capable of accommodating an inclination between the longitudinal axes of the adjacent roll segments. The coupling means may contain a projection or the like on the end surface of the first roll segment and a mating recess on the end surface of the second roll segment. The projection can be formed, e.g., by an annular flange projection made to the end surface of the support shaft with a shape allowing limited rotation and inclination of the projection in a concentric annular recess made to the end surface of the adjacent roll segments when the adjacent roll segments are coupled to each other. Alternatively, one of the mating coupling surfaces may be formed by a concave hemispherical surface, whereby the mating end surface is formed by a convex hemispherical surface. In this arrangement for bowing the segmented roll to a desired curvedness, only one of the mating ends of the adjacent roll segments needs to be directly supported to the mounting frame, while support for the other end is provided by the end of the adjacent roll segment. 
     The support shaft of the roll segment is comprised of two parts adapted to be solidly, advantageously nonrotatably, lockable to each other with the help of a locking element. After the locking element is released, the shaft parts can be axially moved with respect to each other by a distance allowing the coupling means formed on the mating end surfaces of the abutting roll segments to be withdrawn apart from each other. 
     Advantageously, the first part of the support shaft includes an axial projection, most advantageously like a peg that is adapted to fit into an axial bore of the second part of the support shaft. The locking element can be a fastening member, advantageously a lock screw, placed into a radial hole made to one end of the support shaft, the tip of the locking element in its locking position being adapted to press against the outer circumference of the support shaft axial projection thus being capable of solidly locking both parts of the support shaft to each other. 
     Preferably, the lock screw or similar locking element also has another functional position. To this end, the length of the lock screw is advantageously made such that when the lock screw is turned away from resting against the outer circumference of the axial projection, the screw head will tuck against the inner circumference of the roll segment shell thus coupling the other part of the support shaft to follow a possible movement of the roll segment shell. The inner circumference of the roll segment shell is adavantageously provided with a recess suitable for assuring positive contact of the screw head with the roll segment shell when the roll segment is being rotated. 
     Advantageously, at least a portion of the axial projection part and the axial recess part connecting the abutting parts of the support shaft to each other have compatible outer and inner threads, respectively, made thereto. Thus, having first the locking means disengaged, it is possible with the help of the threaded portions to move one part of the support shaft by rotation thereof in regard to the other part in the axial direction. 
     Advantageously, the roll segment of the segmented roll according to the invention is comprised of an outer shell and an inner shell connected to each other by a disc portion. Both parts of the support shaft are provided with an annular recess opening toward the interior of the roll segment, said recesses being adapted to accommodate the tubular flange parts of the inner shell extending to both sides from said disc portion. Each roll segment is rotatably mounted on the support shaft preferably using two bearings, advantageously ball bearings, having their inner races fixed to the rotating inner shell of the roll segment and their outer races fixed to the inner surfaces of the outer walls of the annular recesses made to the support shaft. 
     Advantageously, the segmented roll comprises a plurality of roll segments having their support shafts mounted only at one end on the mounting frame of the segmented roll, complemented with one roll end segment having its both ends mounted on the mounting frame. The mounting arrangement of the support shaft end on the frame is advantageously such that allows the position on and/or distance of the roll segment end to be adjusted in regard to the mounting frame. 
     In a segmented roll embodiment according to the invention, it is possible to replace any single roll segment in the central area of the segmented roll without the need for complete disassembly of the entire segmented roll assembly. To this end, only one end of each roll segment is mounted on the segmented roll mounting frame, while the other end is supported on the adjacent roll segment by means of a coupling that can be disengaged through adjusting the support shaft of the roll segment to a shorter length. 
     As the bowing point between two adjacent roll segments is arranged to coincide with the mating plane of their ends, the segmented roll will bow evenly without any toothed jaggedness in its curvature. Hence, the segmented roll is unproblematically suited for supporting a web, for instance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following the invention will be described by way of an example with reference to the appended drawings, whereby the details thereof are not understood to limit the scope of the invention, in which diagrams 
     FIG. 1 shows a side view of a segmented roll according to the invention; 
     FIG. 2 shows a partially cross-sectional side view of one roll segment of the segmented roll; 
     FIG. 3 shows the roll segment of FIG. 2 as seen from the direction of arrow A; 
     FIG. 4 shows in a partially cross-sectional side view the coupling between two adjacent roll segments of the segmented roll and the structure of the roll end segment; and 
     FIG. 5 shows another embodiment of the roll segment suited for use in a segmented roll according to the invention; 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, the segmented roll schematically illustrated therein comprises five roll segments  10  in an end-to-end succession, whereby the first four of the roll segments are mounted by their one ends via a support member  23  on a mounting frame  5 , while their other ends are supported on the end surface of the respective adjacent roll segment  10 . The last roll segment  10 ′ of the row of roll segments has both of its ends mounted on the mounting frame  5 . Each of the roll segments  10  has a nonrotating support shaft of its own, on which it is adapted to rotate on bearings. The coupling between two adjacent roll segments  10  is adapted to permit a limited angle of inclination between the end-to-end adjacent roll segments  10 . The mounting of the roll segments  10  on the mounting frame  5  is made such that allows the position of any single roll segment  10  to be adjusted both in regard to its height as well as its lateral disposition thus making it possible to adjust the bow of the segmented roll in an uncomplicated manner. 
     In the following, the structure of a single roll segment  10  is described by making reference to FIGS. 2 and 3. The discussion relates to any of the intermediate roll segments illustrated in FIG.  1 . The structure of the roll end segment differs from that of the intermediate roll segments only therein that the roll end segment has both of its ends equipped with a support member  23  (see FIG.  4 ). 
     Each roll segment  10  is comprised of two concentric cylindrical shell parts  12  and  13  connected to each other by a disc portion  14  situated in the central symmetry plane of the cylindrical shell parts. The roll segment  10  is advantageously made by casting. In the roll segment, the outer cylindrical part  12  forms the shell proper that in a segmented roll serving as a spreader roll advantageously has a grooved outer surface. In the axial direction, the inner cylindrical shell part  13  has a length shorter than that of the outer shell part  12  and has the support shaft  11  of the roll segment adapted to pass therethrough. 
     The support shaft  11  of the roll segment is formed by two flange-like parts that are later in the text denoted as an intermediate support member  16  and an intermediate connection member  18 . These members  16  and  18  are adapted into the interior space of the roll segment  10  so that the surfaces of the intermediate support member  16  and the intermediate connection member  18  directed axially outward from the center of the roll segment  10  serve as the end surfaces of the roll segment  10  and, additionally, as the mating surfaces in the coupling between two adjacent roll segments. The two parts of the support shaft  11  are connected to each other by a stub shaft  17  that is incorporated in the intermediate support member  16  and has a length extending through the inner shell  13  of the roll segment into the center bore  19  of the intermediate connection member  18 . In the normal position of the assembly serving the operation of the segmented roll, the support shaft members  16  and  18  are locked to each other nonrotatingly by means of a lock screw  36 . 
     The intermediate support member  16  is mounted on the mounting frame  5  of the segmented roll via a support member  23  which may be separate from or integral with the intermediate support member  16 . In FIG. 1 are schematically shown the fastening and adjustment means  21 ,  22  associated with the support member  23 , advantageously implemented by means of adjustment screws that facilitate the position adjustment of the intermediate support member  16  both vertically and laterally in regard to the segmented roll mounting frame  5 . This arrangement permits the bow of the segmented roll to be controlled by adjusting the position of any roll segment  10  separately in regard to its adjacent roll segments. 
     A stub shaft  17  having an annular recess  27  surrounding its base projects from the center of the disc-like portion of the intermediate support member  16  in the direction of the interior space of the roll segment  10 . This recess serves to accommodate the tubular flange part of the inner shell  13  of the roll segment  10  projecting toward the intermediate support member  16 . In the axial direction, the stub shaft  17  extends through the bore of the inner shell  13  of the roll segment  10  close to the other end of the roll segment  10 . The outer end of the stub shaft  17  has a portion  30  with male thread  32  and there is a flattened area  31  arranged in the perimeter of said threaded portion (see FIG.  3 ). 
     The intermediate connection member  18  located on the other side of the roll segment  10  functions as a mating member to the intermediate support member  16  so that said members  16 ,  18  together form a support shaft  11  of the roll segment  10 . Also the intermediate connection member  18  is shaped into a disc-like piece having a sleeve portion  33  projecting from its center toward the interior space of the roll segment. The sleeve portion  33  has an annular recess  34  made at its base serving to accommodate the tubular flange part of the inner shell  13  of the roll segment  10  projecting toward the intermediate connection member  18 . The axial bore  19  of the sleeve portion  33  extends through the entire length of the intermediate connection part  18  up to the terminal end of the sleeve portion. Both the stub shaft  17  of the intermediate support member  16  and the sleeve portion  33  of the intermediate connection member  18  have an outer diameter slightly smaller than the inner diameter of the inner shell  13  of the roll segment  10 , thus avoiding any direct contact between the inner shell  13  with the parts  17  and  33  of the support shaft  11  passing therethrough. 
     From the outer perimeter of the intermediate connection member  18  inward is drilled an inner-threaded hole  35  reaching radially perpendicular to the longitudinal axis of the roll segment  10  up to the bore  19  drilled axially through the intermediate connection member  18 . Into this threaded hole  35  is placed a lock screw  36  acting as a locking means that has two functional positions. In the first position of the screw  36 , its tip that is directed toward the longitudinal axis of the roll segment is driven tightly against the flat area  31  on the periphery of the terminal end  30  of the stub shaft  17 . Then, the screw  36  serves to lock the intermediate connection member  18  solidly to the stationary intermediate support member  16  so as to prevent rotation of the intermediate connection member  18 . To prevent unintentional excessive tightening of the screw  36  against the flat area  31  of the stub shaft  17 , the cap end of the lock screw  36  that is directed radially outward from the stub shaft is provided with a bushing  37  adapted to meet the perimeter of the intermediate connecting member  18  about the hole  35  when the tip of the lock screw  36  is compressed against the flat area  31  of the stub shaft  17 . Advantageously, the perimeter of the intermediate connection member  18  can be machined to have a partially flat key area (not shown) extending about the hole  35 , whereby the bushing  37  can evenly rest on said flat key area. 
     At least that portion of the axial bore  19  of the intermediate connection member  18  which extends from the hole  35  up to the outer end surface of the intermediate connection member  18  is provided with an inner thread  42  compatible with the outer thread  32  of the terminal end  30  of the stub shaft  17  of the intermediate support member  16 . 
     The roll segment  10  is rotatingly mounted on two ball bearings  20  running on the support shaft  11  formed by the intermediate support member  16  and the intermediate connection member  18 . The bearings are adapted to both sides of the disc portion  14  of the roll segment  10 , on the outer surface of the inner shell  13  so that the inner races of the bearings  20  rotate with the inner shell  13 . The inner shell  13  is formed by two tubular flange parts which extend to both sides from the disc portion  14  and are enclosed by an annular recess  27  on the side facing the intermediate support member  16  and by a respective annular recess  34  on the side facing the intermediate connection member  18 . The stationary outer races of the bearings  20  are then supported on the inner surfaces of the outer walls of these two annular recesses  27  and  34 . 
     As noted above, the inner surface of the inner shell  13  of the roll segment  10  has no direct contact with the members  17 ,  19  of the support shaft  11  passing through the bore of the roll segment&#39;s inner shell  13 . Hence, the bearings  20  are the only point at which the roll segment  10  is connected to the support shaft  11 . The chief function of the stub shaft  17  of the intermediate support member  16  together with the sleeve portion  33  of the intermediate connection member  18  fitted into the central bore of the inner shell  13  is to form the coupling elements for connecting the support shaft members  16  and  18  to each other. 
     In FIG. 4 is shown the structure of the last roll segment  10 ′. As the last roll segment  10 ′ needs to be supported at its both ends to the mounting frame, its support shaft  11 ′ is comprised of the above-described standard-type intermediate support member  16  connected to an end support member  16 ′, whose structure combines certain characteristic details of the standard-type intermediate support member  16  and those of the intermediate connection member  18 . 
     The coupling means for connecting two adjacent roll segments  10  to each other are formed on the end surfaces of the support shaft  11  of the roll segment. As can be seen from FIG. 2 illustrating the roll segment  10 , the outer surface of the intermediate connection member  18  has an annular flange projection  41  made thereon, while the outer surface of the intermediate support member  16  has an annular groove  29  made thereon with a shape essentially concentrically compatible with that of the annular flange projection  41 . 
     In the following, the coupling formed between adjacent roll segments  10  and the removal of a single roll segment from the central area of the segmented roll is described by making reference to FIG. 4, as well as to FIG. 2 for details related to the structure of the roll segment  10 . 
     Accordingly, the universal joint between two adjacent roll segments  10  is formed between the end surfaces of the first roll segment&#39;s intermediate connection member  18  and the second roll segment&#39;s intermediate support member  16 . When two roll segments  10  are aligned end-to-end abutting each other, the annular flange projection  41  made to the end surface of the first roll segment&#39;s intermediate connection member  18  enters the annular recess  29  made to the end surface of the second roll segment&#39;s intermediate support member  16 , wherein it can rotate and tilt within the limits provided by a suitably arranged play. The maximum inclination can be increased by proper beveling of the edges of the annular flange projection  41  and the annular recess  29 . 
     By virtue of arranging the bowing point of two adjacent roll segments  10  to coincide in the above-described manner with the mating surface of the roll segments  10 , the segmented roll can bow without any jaggedness between two adjacent roll segments  10 . 
     To remove a roll segment  10  from the central area of the segmented roll according to the invention, the first step comprises unscrewing the lock screw  36  of the support shaft  11  that fixes nonrotatingly the intermediate connection member  18  to the intermediate support member  16  of the roll segment. To facilitate unscrewing the lock screw  36  from outside the roll segment, the outer shell  12  of the roll segment is provided with an opening  39  drilled in a position coinciding with the head of the lock screw  36  and having a recess  40  made about said opening on the inner surface of the outer shell  12  of the roll segment (see FIG.  3 ). Then, the unscrewing of the screw  36  can be performed by inserting through the opening  39  a tool by means of which the lock screw  36  is rotated until the head  38  of the lock screw meets the recess  40  made to the inner surface of the roll segment&#39;s outer shell  12 . By this time, the tip of the lock screw  36  has been released from the contact with the stub shaft  17  of the intermediate support member  16  and the head of the lock screw  36  has locked intermediate connection member  18  to rotate with the outer shell  12 . Now the roll segment  10  can be rotated in a proper direction by a suitable number of turns depending on the pitch of the threads  32 ,  42  so that the intermediate connection member  18  rotates with the roll segment  10 . Thereby, the cooperation of the outer thread  32  made on the terminal end of the stub shaft  17  and the inner thread  42  made into the center bore  19  of the intermediate connection member  18  force the intermediate connection member  18  to move supported by the stub shaft  17  toward the intermediate support member  16 . This movement causes the annular flange projection  41  of the end surface of the intermediate connection member  18  to withdraw from the annular recess  29  of the end surface of the adjacent roll segment thus disengaging the roll segment  10  from the connection with the adjacent roll segment. 
     The above-described steps must be repeated for the roll segment adjoining the other end of the roll segment  10  to be removed, whereafter the support member  23  of the roll segment  10  can be dismounted from the mounting frame and the roll segment  10  removed from its place. The reassembly of the roll segment back to the row of adjacent roll segments takes place in a reversed order. 
     In FIG. 5 is shown another embodiment of the roll segment suitable for use in a segmented roll and particularly the connection members of the roll segment. The structure of the roll segment is chiefly identical to that of the roll segment shown in FIG.  2 . The connection members comprise a projection  45  formed by a convex hemispherical surface on the end surface of the intermediate connection member  18  and, on the end surface of the intermediate support member  16 , a recess  46  having the shape of a concave hemispherical surface which is essentially concentric and of equal radius of curvature with that of the mating end surface formed by the projection  45 . Then, engaging two roll segments of the kind shown in FIG. 5 into an intimate connection with each other forms a universal joint surface between the projection  45  and the recess  46  that allows different angles of inclination between the axes of the adjacent roll segments. This kind of support joint between the two adjacent roll segments can be disassembled by way of moving the intermediate support member  16  and the intermediate coupling member in the manner described in conjunction with the former exemplifying embodiment. 
     Also other implementations of the segmented roll structure according to the invention can be contemplated. Advantageously, the coupling elements at the end surfaces of the roll segments are concentric members, whereby the release of the support joint between the adjacent roll segments can be arranged to take place by rotation. The coupling member may be, e.g., a threaded bushing attached to the end of the intermediate support member stub shaft and arranged to fit into a recess made to the end surface of the adjacent roll segment when the roll segments are in their coupled position. Then, the entire body of the intermediate support member need not necessarily be movable toward the support member of the roll segment, but instead, the contraction of the support shaft length can be simply accomplished by rotating the threaded bushing along the roll segment support shaft toward the support member.