SEGMENTED VACUUM ROLL

Abstract: A segmented vacuum roll comprising an inner assembly on which a plurality of cylindrical sleeve tubes (2a, 2b, 2c) having apertures over their circumference are rotatably and coaxially mounted side by side, each of said sleeve tubes being individually rotatable and one or several first chambers (9a, 9b, 9c) formed in said inner assembly and partly defined by a first portion of circumference of said sleeve tubes, said inner assembly comprising linking means (6a, 6b, 6c) for linking a vacuum source to said chambers so that said first portion of circumference of said sleeve tubes may be submitted to vacuum. Said inner assembly comprises an inner tube (3), at least one outer tube (5a, 5b, 5c) surrounding said inner tube and a plurality of longitudinal walls extending between said inner tube and said outer tube so as to form longitudinal channels (6a, 6b, 6c) making part of said linking means.

Description: SEGMENTED VACUUM ROLL FIELD OF THE INVENTION The invention relates to a vacuum roll for conveying webs and, more particularly, to a vacuum roll having several segments each of which being able to convey a separate web resulting, for instance, from a main web split into several webs of smaller wide. BACKGROUND OF THE INVENTION Webs such as polymeric foils (like polyester foils) or other sheet materials are manufactured in a continuous process and the final products are wound up on rolls for storage and transportation. On such production lines or on converting rewinding machines, vacuum rolls may be used to transport, pull, guide (or even dry) the web. Those vacuum rolls are known in the art for a long time. However, on the production line or on a converting equipment, the web may be split into several lanes and each lane may have to be transported, pulled or guided individually, at a speed different from the speed of the other lanes. SUMMARY OF THE INVENTION The object of the present invention is to provide a segmented vacuum roll each segment of which is rotatable independently from the other segments so that each segment drives a respective web at an own speed according to the need of the process. This object is achieved with a vacuum roll according to claim 1. Preferred embodiments are defined in the depending claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. la and lb schematically show respectively the left half and the right half of a longitudinal section according to line A-A shown in fig. 2 of a segmented vacuum roll according to the invention; Fig. 2 schematically shows a cross section of the segmented vacuum roll of fig. 1 according to line B-B; Fig. 3 schematically shows a cross section of the segmented vacuum roll of fig. 1 according to line C-C; Fig. 4 schematically shows a cross section of the segmented vacuum roll of fig. 1 according to line D-D; Fig. 5 schematically shows a cross section of the segmented vacuum roll of fig. 1 according to line E-E; Fig. 6 schematically shows a cross section of the segmented vacuum roll of fig. 1 according to line F-F; Fig. 7 schematically shows a lateral view of the segmented vacuum roll of fig. 1 completed with the driving arrangement for its segments. DETAILED DESCRIPTION OF THE INVENTION FigJa and lb show respectively the left half and the right half of a longitudinal section of a segmented vacuum roll according to a preferred embodiment of the invention. The segmented vacuum roll comprises five segments la, lb, lc, Id and le disposed side by side. The segmented vacuum roll is based on a common fixed inner assembly on which are rotatably mounted side by side five sleeve tubes 2a, 2b, 2c, 2d and 2e corresponding each to a respective segment la, lb, lc, Id and le. Those sleeve tubes 2a, 2b, 2c, 2d and 2e preferably have the same inner and outer diameter and have each a quantity of apertures or perforations over their whole surface through which the vacuum effect will be exerted. Said perforations may be of any type (holes, slots) and size (microscopic or macroscopic). Sleeve tubes 2a, 2b, 2c, 2d and 2e are known per se. The segmented vacuum roll comprises at each end a support 26a, respectively 26b for mounting purpose. For each segment la, lb, lc, Id and le, the common inner assembly forms a respective chamber 9a, 9b, 9c, 9d and 9e one wall of which is formed by a portion of the corresponding sleeve tube 2a, 2b, 2c, 2d and 2e. Each chamber 9a, 9b, 9c, 9d and 9e is connected to a respective vacuum generator (not shown) via a respective channel 6a, 6b, 6c, 6d and 6e. To form said chambers 9a, 9b, 9c, 9d and 9e and said channels 6a, 6b, 6c, 6d and 6e, the inner assembly comprises an inner tube 3 passing through the whole segmented vacuum roll and five outer tubes 5a, 5b, 5c, 5d and 5e mounted side by side and coaxial on inner tube 3 as well as several longitudinal walls between them and separating disks. Inner tube 3 and outer tubes 5a, 5b, 5c, 5d and 5e have preferably a cylindrical cross section. We will now describe each segment la, lb, lc, Id and le. First segment la will be described in relation with fig. la and 3. First segment l a comprises sleeve tube 2a. Sleeve tube 2a is rotatably mounted by each end on inner tube 3 via an end disk 4a on the free end side of the segmented vacuum roll and via a separator disk 4b on the side towards second segment lb. End disk 4a as well as separator disk 4b have a central hole corresponding substantially to the outer diameter of inner tube 3 so that they may be mounted on the latter. The joint between end disk 4a and inner tube 3 and the joint between separator disk 4b and inner tube 3 are preferably welded in a substantially sealed manner. Sleeve tube 2 is rotatably mounted on end disk 4a and separator disk 4b via respectively a ball bearing 17a and a first ball bearing 17b. Outer tube 5a is mounted coaxial on inner tube 3 between end disk 4a and separator disk 4b. Outer tube 5a has preferably substantially the same outer diameter than end disk 4a and separator disk 4b, but it could also be smaller. As a result, sleeve tube 2a surrounds also outer tube 5a. Five longitudinal walls 10a, 1 1a, 12a, 13a, andl4a extend preferably radially between inner tube 3 and outer tube 5a in spaced relationship from one another around the circumference of inner tube 3. The circumference portion of outer tube 5a comprised between wall 10a and wall 14a is omitted so that the space comprised between wall 10a and wall 14a is limited in outward direction by the corresponding circumference portion of sleeve tube 2a. A further longitudinal wall 15a extending preferably radially is arranged on inner tube 3 between wall 10a and 14a. Walls 10a, 1 1a, 12a, 13a, 14a and 15a extend longitudinally from end disk 4a to separator disk 4b. The space between wall 10a and wall 15a and limited radially by the corresponding portion of inner tube 3 and sleeve tube 2a defines chamber 9a. The space between wall 15a and wall 14a and limited radially by the corresponding portion of inner tube 3 and sleeve tube 2a defines a chamber 21a. Preferably, said walls 10a, 1 la, 12a, 13a, 14a andl5a are welded on inner tube 3 as well as on end disk 4a and separator disk 4b and are glued on outer tube 5a, both in a substantially sealed manner. Thus, the space defined between two successive walls (chosen among walls 10a, 11a, 12a, 13a and 14a) as well as the portions of inner tube 3 and outer tube 5a comprised between the latter forms a channel usable to transmit vacuum if relevant. Two holes 18a are arranged on inner tube 3 between walls 10a and 15a so that chamber 9a communicates with the inside of inner tube 3. A separator disk 7a is arranged in press fit manner inside of inner tube 3 at substantially the same longitudinal level than separator disk 4b mounted outside of inner tube 3. Preferably, a seal 19a is disposed in a groove arranged on the circumference of separator disk 7a in order to provide a sealing between separator disk 7a and inner tube 3. The inside of inner tube 3 corresponding to the segment la side (i.e. the portion of inner tube 3 extending from separator disk 7a towards the end of inner tube 3 on the side of end disk 4a) forms channel 6a connected at its free end to a vacuum generator (not shown) via a sleeve 20a. Thus, vacuum is transmitted from said vacuum generator to chamber 9a successively through sleeve 20a, channel 6a and holes 18a. As already mentioned, chamber 9a is delimited in outward direction by a circumference portion of sleeve tube 2a which is perforated. As a consequence, the vacuum effect will be exerted through the perforations of that circumference portion, i.e. it is the active portion of segment la of the segmented vacuum roll. On the other hand, no vacuum effect is exerted on the remaining circumference portion of sleeve tube 2a. Of course, the gap between sleeve tube 2a and outer tube 5a taken at the level of wall 10a is preferably minimized in order to avoid vacuum leakage. Similarly, the gap between sleeve tube 2a and wall 15a is also preferably minimized for the same reason. As a result, when a web is placed on segment la, it will be sucked onto the active portion of sleeve tube 2a through the action of vacuum existing in chamber 9a. Further, when sleeve tube 2a is caused to rotate, it will drive the web. The means for causing sleeve tube 2a to rotate will be described later. Second segment lb will be described in relation with fig. la, 2, 3 and 4. Second segment lb comprises sleeve tube 2b. Sleeve tube 2b is rotatably mounted by each end on inner tube 3 via separator disk 4b on the side towards first segment la and via a separator disk 4c on the side towards third segment lc. Separator disk 4c has a central hole corresponding substantially to the outer diameter of inner tube 3 so that it may be mounted on the latter. The joint between separator disk 4c and inner tube 3 is preferably welded in a substantially sealed manner. Sleeve tube 2b is rotatably mounted on separator disk 4b via a second ball bearing 17b arranged aside first ball bearing 17b which supports sleeve tube 2a. Sleeve tube 2b is further rotatably mounted on separator disk 4c via a first ball bearing 17c. Outer tube 5b is mounted coaxially on inner tube 3 between separator disk 4b and separator disk 4c. Outer tube 5b has preferably substantially the same outer diameter than separator disks 4b and 4c, but it could also be smaller. As a result, sleeve tube 2b surrounds also outer tube 5b. Five longitudinal walls 10b, l ib, 12b, 13b andl4b extend preferably radially between inner tube 3 and outer tube 5b in spaced relationship from one another around the circumference of inner tube 3. The circumference portion of outer tube 5b comprised between wall 10b and wall 14b is omitted so that the space comprised between wall 10b and wall 14b is limited in outward direction by the corresponding circumference portion of sleeve tube 2b. A further longitudinal wall 15b extending preferably radially is arranged on inner tube 3 between wall 10b and 14b. Walls 10b, l ib, 12b, 13b, 14b and 15b extend longitudinally from separator disk 4b to separator disk 4c. Further, walls 10b, 1 lb, 12b, 13b, 14b and 15b are substantially aligned respectively with walls 10a, 1 la, 12a, 13a, 14a and 15a. The space between wall 10b and wall 15b limited radially by the corresponding portions of inner tube 3 and sleeve tube 2b defines chamber 9b. The space between wall 15b and wall 14b limited radially by the corresponding portion of inner tube 3 and sleeve tube 2b defines a chamber 21b. Preferably, said walls 10b, 1 lb, 12b, 13b, 14b and 15b are welded on inner tube 3 as well as on separator disk 4b and separator disk 4c and are glued on outer tube 5b, both in a substantially sealed manner. Thus, the space defined between two successive walls (chosen among walls 10b, 1 lb, 12b, 13b and 14b) as well as the portions of inner tube 3 and outer tube 5b comprised between the latter forms a channel usable to transmit vacuum if relevant. A curved oblong hole 16b is arranged in separator disk 4b between, on one hand, wall 10a and wall 10b and, on the other hand, wall 1 la and wall 1 lb. Thus, the space between walls 10a and 1 1a and walls 10b and l ib limited radially by the corresponding portions of inner tube 3 and respectively outer tubes 5a and 5b defines channel 6b extending longitudinally from separator disk 4c to end disk 4a. Several holes 18b are arranged in wall 10b allowing channel 6b to communicate with chamber 9b. A curved oblong hole 16a is arranged in end disk 4a between wall 10a and wall 1 la. An adapter 20b is mounted on the end of the segmented vacuum roll on the end disk 4a side which puts in communication hole 16a with an external vacuum generator (not shown). Thus, vacuum is transmitted from said vacuum generator to chamber 9b successively through hole 16a, channel 6b (comprising hole 16b) and holes 18b. As already mentioned, chamber 9b is delimited in outward direction by a circumference portion of sleeve tube 2b which is perforated. As a consequence, the vacuum effect will be exerted through the perforations of that circumference portion, i.e. it is the active portion of segment lb of the segmented vacuum roll. On the other hand, no vacuum effect is exerted on the remaining circumference portion of sleeve tube 2a. Of course, the gap between sleeve tube 2b and outer tube 5b taken at the level of wall 10b is preferably minimized in order to avoid vacuum leakage. Similarly, the gap between sleeve tube 2b and wall 15b is also preferably minimized for the same reason. As a result, when a web is placed on segment lb, it will be sucked onto the active portion of sleeve tube 2b through the action of vacuum existing in chamber 9b. Further, when sleeve tube 2b is caused to rotate, it will drive the web. The means for causing sleeve tube 2b to rotate will be described later. Third segment lc will be described in relation with fig. la, lb, 2, 3, 4 and 5. Third segment lc comprises sleeve tube 2c. Sleeve tube 2c is rotatably mounted by each end on inner tube 3 via separator disk 4c on the side towards second segment 1 b and via a separator disk 4d on the side towards fourth segment I d. Separator disk 4d has a central hole corresponding substantially to the outer diameter of inner tube 3 so that it may be mounted on the latter. The joint between separator disk 4d and inner tube 3 is preferably welded in a substantially sealed manner. Sleeve tube 2c is rotatably mounted on separator disk 4c via a second ball bearing 17c arranged aside first ball bearing 17c which supports sleeve tube 2b. Sleeve tube 2c is further rotatably mounted on separator disk 4d via a first ball bearing 17d. Outer tube 5c is mounted coaxially on inner tube 3 between separator disk 4c and separator disk 4d. Outer tube 5c has preferably substantially the same outer diameter than separator disks 4c and 4d, but it could also be smaller. As a result, sleeve tube 2c surrounds also outer tube 5c. Five longitudinal walls 10c, l ie, 12c, 13c and 14c extend preferably radially between inner tube 3 and outer tube 5c in spaced relationship from one another around the circumference of inner tube 3. The circumference portion of outer tube 5c comprised between wall 10c and wall 14c is omitted so that the space comprised between wall 10c and wall 14c is limited in outward direction by the corresponding circumference portion of sleeve tube 2c. A further longitudinal wall 15c extending preferably radially is arranged on inner tube 3 between walls 10c and 14c. Walls 10c, l ie, 12c, 13c, 14c and 15c extend longitudinally from separator disk 4c to separator disk 4d. Further, walls 10c, 1 lc, 12c, 13c, 14c and 15c are substantially aligned respectively with walls 10b, l ib, 12b, 13b, 14b and 15b. The space between wall 10c and wall 15c limited radially by the corresponding portions of inner tube 3 and sleeve tube 2c defines chamber 9c. The space between wall 15c and wall 14c limited radially by the corresponding portion of inner tube 3 and sleeve tube 2c defines a chamber 21c. Preferably, said walls 10c, 1 lc, 12c, 13c, 14c and 15c are welded on inner tube 3 as well as on separator disk 4c and separator disk 4d and are glued on outer tube 5c, both in a substantially sealed manner. Thus, the space defined between two successive walls (chosen among walls 10c, 1 lc, 12c, 13c and 14c) as well as the portions of inner tube 3 and outer tube 5c comprised between the latter forms a channel usable to transmit vacuum if relevant. A curved oblong hole 23c is arranged in separator disk 4c between, on one hand, wall 12b and wall 12c and, on the other hand, wall 13b and wall 13c. Similarly, a curved oblong hole 23b is arranged in separator disk 4b between, on one hand, wall 12a and wall 12b and, on the other hand, wall 13a and wall 13b. Thus, the space between walls 12a and 13a, walls 12b and 13b and walls 12c and 13c limited radially by the corresponding portions of inner tube 3 and respectively outer tubes 5a, 5b and 5b defines channel 6c extending longitudinally from separator disk 4d to end disk 4a. A separator disk 7b is arranged in press fit manner inside of inner tube 3 at substantially the same longitudinal level than separator disk 4e (described later in relation with fifth segment le) mounted outside of inner tube 3. Preferably, a seal 19b is disposed in a groove arranged on the circumference of separator disk 7b in order to provide a sealing between separator disk 7b and inner tube 3. Thus, the space inside of inner tube 3 comprised between separator disk 7a and separator disk 7b defines a sealed chamber 24. Several holes 18c are arranged in the portion of inner tube 3 comprised between wall 10c and wall 15c, said holes allowing chamber 24 to communicate with chamber 9b. Similarly, several holes 18c' are arranged in the portion of inner tube 3 comprised between wall 12c and wall 13c, said holes allowing channel 6c to communicate with chamber 24. A curved oblong hole 23a is arranged in end disk 4a between wall 12a and wall 13a. An adapter 20c is mounted on the end of the segmented vacuum roll on the end disk 4a side which puts in communication hole 23a with an external vacuum generator (not shown). Thus, vacuum is transmitted from said vacuum generator to chamber 9c successively through hole 23a, channel 6c (comprising holes 23b and 23c), holes 18c', chamber 24 and holes 18c. As already mentioned, chamber 9c is delimited in outward direction by a circumference portion of sleeve tube 2c which is perforated. As a consequence, the vacuum effect will be exerted through the perforations of that circumference portion, i.e. it is the active portion of segment lc of the segmented vacuum roll. On the other hand, no vacuum effect is exerted on the remaining circumference portion of sleeve tube 2c. Of course, the gap between sleeve tube 2c and outer tube 5c taken at the level of wall 10c is preferably minimized in order to avoid vacuum leakage. Similarly, the gap between sleeve tube 2c and wall 15c is also preferably minimized for the same reason. As a result, when a web is placed on segment lc, it will be sucked onto the active portion of sleeve tube 2c through the action of vacuum existing in chamber 9c. Further, when sleeve tube 2c is caused to rotate, it will drive the web. The means for causing sleeve tube 2c to rotate will be described later. Fifth segment le will be described in relation with fig. lb and 6. Fifth segment le is designed symmetrically to first segment la. Fifth segment le comprises sleeve tube 2e. Sleeve tube 2e is rotatably mounted by each end on inner tube 3 via an end disk 4f on the free end side of the segmented vacuum roll (opposite to the side with end disk 4a) and via a separator disk 4e on the side towards end disk 4a. End disk 4f as well as separator disk 4e have a central hole corresponding substantially to the outer diameter of inner tube 3 so that they may be mounted on the latter. The joint between end disk 4f and inner tube 3 and the joint between separator disk 4e and inner tube 3 are preferably welded in a substantially sealed manner. Sleeve tube 2e is rotatably mounted on end disk 4f and separator disk 4e via respectively a ball bearing 17f and a first ball bearing 17e. Outer tube 5e is mounted coaxially on inner tube 3 between end disk 4f and separator disk 4e. Outer tube 5e has preferably substantially the same outer diameter than end disk 4f and separator disk 4e, but it could also be smaller. As a result, sleeve tube 2e surrounds also outer tube 5e. Five longitudinal walls lOe, l ie, 12e, 13e, and 14e (not shown) extend preferably radially between inner tube 3 and outer tube 5e in spaced relationship from one another around the circumference of inner tube 3. The circumference portion of outer tube 5e comprised between wall lOe and wall 14e is omitted so that the space comprised between wall lOe and wall 14e is limited in outward direction by the corresponding circumference portion of sleeve tube 2e. A further longitudinal wall 15e (not shown) extending preferably radially is arranged on inner tube 3 between wall lOe and 14e. Walls lOe, l ie, 12e, 13e, 14e and 15e extend longitudinally from end disk 4f to separator disk 4e. The space between wall l Oe and wall 15e limited radially by the corresponding portion of inner tube 3 and sleeve tube 2e defines chamber 9e. The space between wall 15e and wall 14e limited radially by the corresponding portion of inner tube 3 and sleeve tube 2e defines a chamber 21e (not shown). Preferably, said walls lOe, l ie, 12e, 13e, 14e and 15e are welded on inner tube 3 as well as on end disk 4f and separator disk 4e and are glued on outer tube 5e, both in a substantially sealed manner. Thus, the space defined between two successive walls (chosen among walls lOe, l ie, 12e, 13e and 14e) as well as the portions of inner tube 3 and outer tube 5e comprised between the latter forms a channel usable to transmit vacuum if relevant. Two holes 18e are arranged on inner tube 3 between walls lOe and 15e so that chamber 9e communicates with the inside of inner tube 3. As already mentioned, separator disk 7b is arranged in press fit manner inside of inner tube 3 at substantially the same longitudinal level than separator disk 4e mounted outside of inner tube 3. Preferably, a seal 19b is disposed in a groove arranged on the circumference of separator disk 7b in order to provide a sealing between separator disk 7b and inner tube 3. The inside of inner tube 3 corresponding to segment le side (i.e. the portion of inner tube 3 extending from separator disk 7b towards the end of inner tube 3 on the side of end disk 4f) forms channel 6e connected at its free end to a vacuum generator (not shown) via a sleeve 20e. Thus, vacuum is transmitted from said vacuum generator to chamber 9e successively through sleeve 20e, channel 6e and holes 18e. As already mentioned, chamber 9e is delimited in outward direction by a circumference portion of sleeve tube 2e which is perforated. As a consequence, the vacuum effect will be exerted through the perforations of that circumference portion, i.e. it is the active portion of segment le of the segmented vacuum roll. On the other hand, no vacuum effect is exerted on the remaining circumference portion of sleeve tube 2e. Of course, the gap between sleeve tube 2e and outer tube 5e taken at the level of wall l Oe is preferably minimized in order to avoid vacuum leakage. Similarly, the gap between sleeve tube 2e and wall 15e is also preferably minimized for the same reason. As a result, when a web is placed on segment le, it will be sucked onto the active portion of sleeve tube 2e through the action of vacuum existing in chamber 9e. Further, when sleeve tube 2e is caused to rotate, it will drive the web. The means for causing sleeve tube 2e to rotate will be described later. Fourth segment Id will be described in relation with fig. lb and 6. Fourth segment Id is designed as second segment lb, but symmetrically. Fourth segment Id comprises sleeve tube 2d. Sleeve tube 2d is rotatably mounted by each end on inner tube 3 via separator disk 4d on the side towards third segment lc and via separator disk 4e on the side towards fifth segment le. Sleeve tube 2d is rotatably mounted on separator disk 4d via a second ball bearing 17d arranged aside first ball bearing 17d which supports sleeve tube 2c. Sleeve tube 2d is further rotatably mounted on separator disk 4e via a second ball bearing 17e arranged aside first ball bearing 17e which supports sleeve tube 2e. Outer tube 5d is mounted coaxially on inner tube 3 between separator disk 4d and separator disk 4e. Outer tube 5d has preferably substantially the same outer diameter than separator disks 4d and 4e, but it could also be smaller. As a result, sleeve tube 2d surrounds also outer tube 5d. Five longitudinal walls l Od, l id, 12d, 13d and 14d (not shown) extend preferably radially between inner tube 3 and outer tube 5d in spaced relationship from one another around the circumference of inner tube 3. The circumference portion of outer tube 5d comprised between wall lOd and wall 14d is omitted so that the space comprised between wall lOd and wall 14d is limited in outward direction by the corresponding circumference portion of sleeve tube 2d. A further longitudinal wall 15d (not sown) extending preferably radially is arranged on inner tube 3 between wall lOd and 14d. Walls lOd, l id, 12d, 13d, 14d and 15d extend longitudinally from separator disk 4d to separator disk 4e. Further, walls lOd, l id, 12d, 13d, 14d and 15d are substantially aligned respectively, on one hand, with walls 10c, l ie, 12c, 13c, 14c and 15c and, on the other hand, with walls lOe, l ie, 12e, 13e, 14e and 15e. The space between wall l Od and wall 15d limited radially by the corresponding portions of inner tube 3 and sleeve tube 2d defines chamber 9d. The space between wall 15d and wall 14d limited radially by the corresponding portion of inner tube 3 and sleeve tube 2d defines a chamber 21d (not shown). Preferably, said walls lOd, l id, 12d, 13d, 14d andl5d are welded on inner tube 3 as well as on separator disk 4d and separator disk 4e and are glued on outer tube 5d, both in a substantially sealed manner. Thus, the space defined between two successive walls (chosen among walls lOd, l id, 12d, 13d and 14d) as well as the portions of inner tube 3 and outer tube 5d comprised between the latter forms a channel usable to transmit vacuum if relevant. A curved oblong hole 25e (not shown) is arranged in separator disk 4e between, on one hand, wall 1 Od and wall 1 Oe and, on the other hand, wall 1 1 d and wall l ie. Thus, the space between walls lOd and l id and walls lOe and l ie limited radially by the corresponding portions of inner tube 3 and respectively outer tubes 5d and 5e defines channel 6d (not shown) extending longitudinally from separator disk 4d to end disk 4f. Several holes 18d are arranged in wall lOd allowing channel 6d to communicate with chamber 9d. A curved oblong hole 25f is arranged in end disk 4f between wall lOe and wall l ie. An adapter 20d is mounted on the end of the segmented vacuum roll on the end disk 4f side which puts in communication hole 25f with an external vacuum generator (not shown). Thus, vacuum is transmitted from said vacuum generator to chamber 9d successively through hole 25f, channel 6d (comprising hole 25e) and holes 18d. As already mentioned, chamber 9d is delimited in outward direction by a circumference portion of sleeve tube 2d which is perforated. As a consequence, the vacuum effect will be exerted through the perforations of that circumference portion, i.e. it is the active portion of segment Id of the segmented vacuum roll. On the other hand, no vacuum effect is exerted on the remaining circumference portion of sleeve tube 2d. Of course, the gap between sleeve tube 2d and outer tube 5d taken at the level of wall lOd is preferably minimized in order to avoid vacuum leakage. Similarly, the gap between sleeve tube 2d and wall 15d is also preferably minimized for the same reason. As a result, when a web is placed on segment Id, it will be sucked onto the active portion of sleeve tube 2d through the action of vacuum existing in chamber 9d. Further, when sleeve tube 2d is caused to rotate, it will drive the web. The means for causing sleeve tube 2d to rotate will be described later. As a result from what has been described up to now, the segmented vacuum roll comprises five vacuum roll segments la, lb, lc, Id and le rotatable independently from one another. The active portion of each segment la, lb, lc, Id and le (i.e. the portion of corresponding sleeve tube 2a, 2b, 2c, 2d and 2e through which the vacuum effect will exert on webs placed on the segmented vacuum roll) is preferably about 90°. In other words, wallsl Oa and 15a, wallslOb and 15b, wallslOc and 15c, walls lOd and 15d and walls lOe and 15e respectively form an angle of about 90°. Fig. 3 illustrates a web 27a driven by segment la. Web 27a arrives substantially horizontally on segment l a and contacts it approximately at the beginning of its active portion (i.e. at the level of wall 10a which is consequently arranged vertically). Web 27a leaves segment la vertically and downwards at a level corresponding approximately to the end of its active portion (i.e. at the level of wall 15a which is consequently arranged horizontally). Of course, sleeve tube 2a is caused to rotate clockwise in the example of fig. 3. The other segments lb, lc, Id and le work similarly. It may be taken from fig. 2, 3, 4, 5 and 6 that two tie rods 41a and 41b passes through the whole segmented vacuum roll. Tie rod 41a passes in the channel formed between walls 1 la and 12a, walls 1 lb and 12b, walls 1 lc and 12c, walls l id and 12d and walls l ie and 12e delimited radially by the corresponding portions of inner tube 3 and outer tubes 5a, 5b, 5c, 5d and 5e, the corresponding portions of separator disks 4b, 4c, 4d and 4e having a hole for passing tie rod 41a. Similarly, tie rod 41b passes in the channel formed between walls 13a and 14a, walls 13b and 14b, walls 13c and 14c, walls 13d and 14d and walls 13e and 14e delimited radially by the corresponding portions of inner tube 3 and outer tubes 5a, 5b, 5c, 5d and 5e, the corresponding portions of separator disks 4b, 4c, 4d and 4e having a hole for passing tie rod 41b. Tie rods 41a and 41b are threaded and provided with nuts at both ends and are tightened in such a way that the deflection of the vacuum roll is cancelled. The segmented vacuum roll may also comprise an air shower in order to ensure that the webs will not adhere on its inactive portions (i.e. the portions of sleeve tubes 2a, 2b, 2c, 2d and 2e where no vacuum effect is exerted on the webs) which would result in an unwished winding of the webs on the segmented vacuum roll. The air shower is obtained by blowing air into chambers 21a, 21b, 21c, 21d and 21e. For that purpose, a hole 28b, 28c, 28d and 28e is arranged respectively in each separator disk 4b, 4c, 4d and 4e between respectively walls 14a and 15a, walls 14b and 15b, walls 14c and 15c, walls 14d and 15d and walls 14e and 15e (hole 28e not shown). Thus, chambers 21a, 21b, 21c, 21d and 21e are in communication one by one. An external air generator (not shown) is connected on a further hole 28a arranged in end disk 4a between walls 14a and 15a. Alternately, it is possible to connect a further air generator on a hole arranged in end disk 4f between walls 14e and 15e. As a result, air will flow through the perforations of the portions of sleeve tubes 2a, 2b, 2c, 2d and 2e corresponding respectively to chambers 21a, 21b, 21c, 21 d and 21 e and will cause the webs to leave the segmented vacuum roll at this location. Alternately, it is also possible to connect each chamber 21a, 21b, 21c, 21 d and 21e to a respective air generator in which case holes 28b, 28c, 28d and 28e are omitted and air transmission from the air generators to the respective chambers could be ensured with channels similarly to vacuum transmission for chambers 9a, 9b, 9c, 9d and 9e. The segmented vacuum roll may also be adapted to the overall width of the web. For that purpose, segment la comprises two longitudinal screws 30a and 30a' extending in chamber la between end disk 4a and separator disk 4b. Screws 30a and 30a' are mechanically coupled to each other (e.g. by means of a timing belt) and guide and actuate an isolation part 29a. The outer shape of isolation part 29a substantially corresponds to the cross section of chamber 9a so that isolation part 29a divides chamber 9a into two sub chambers 9a' and 9a" substantially sealingly isolated from one another. Preferably, a seal 32a is arranged into a groove formed in the outer surfaces on the side of inner tube 3 and of walls 10a and 15a. On the other hand, the gap between isolation part 29a and sleeve tube 2a is preferably minimized. The longitudinal position of isolation part 29a is adjustable by driving screws 30a and 30a' from the outside. Holes 18a arranged on inner tube 3 are preferably located near separator disk 4b. Thus, solely the resulting sub chamber 9a' comprised between isolation part 29a and separator disk 4b is connected to the external vacuum generator via channel 6a. On the contrary, the sub chamber 9a" comprised between isolation part 29a and end disk 4a is not fed with vacuum. As a result, the active portion of sleeve tube 2a is longitudinally limited to the length of sub chamber 9a'. Practically, when the web (split in several webs) is placed on the segmented vacuum roll, it is possible to adapt the position of isolation part 29a so that its longitudinal location substantially corresponds to the external edge of the web on segment la. Thus, there is no vacuum leakage through the portion of sleeve tube 2a not covered by the web. Symmetrically, segment le comprises the same features. Two longitudinal screws 30e and 30e' extend in chamber le between end disk 4f and separator disk 4e. Screws 30e and 30e' are mechanically coupled to each other (e.g. by means of a timing belt) and guide and actuate an isolation part 29e. The outer shape of isolation part 29e substantially corresponds to the cross section of chamber 9e so that isolation part 29e divides chamber 9e into two sub chambers 9e' and 9e" substantially sealingly isolated from one another. Preferably, a seal 32e is arranged into a groove formed in the outer surfaces on the side of inner tube 3 and of walls lOe and 15e. On the other hand, the gap between isolation part 29e and sleeve tube 2e is preferably minimized. The longitudinal position of isolation part 29e is adjustable by driving screws 30e and 30e' from the outside. Holes 18e arranged on inner tube 3 are preferably located near separator disk 4e. Thus, solely the resulting sub chamber 9e' comprised between isolation part 29e and separator disk 4e is connected to the external vacuum generator via channel 6e. On the contrary, the sub chamber 9e" comprised between isolation part 29a and end disk 4f is not fed with vacuum. As a result, the active portion of sleeve tube 2e is longitudinally limited to the length of sub chamber 9e'. Practically, when the web (split in several webs) is placed on the segmented vacuum roll, it is possible to adapt the position of isolation part 29e so that its longitudinal location substantially corresponds to the external edge of the web on segment le. Thus, there is no vacuum leakage through the portion of sleeve tube 2e not covered by the web. Of course, isolation parts 29a and 29e may be moved by any other means known in the art. In reference to fig. 7, we will now describe the means for driving sleeve tube 2a in rotation. Fig. 7 is a lateral view of the segmented vacuum roll: only its mounting support 26a and sleeve tube 2a are depicted (in dot-and-dash lines). The segmented vacuum roll is fixed onto a frame 33. A girder 35 having a square section extending parallel to the segmented vacuum roll is mounted on frame 33 horizontally spaced from the segmented vacuum roll. Girder 35 is somewhat longer than the segmented vacuum roll and is fixed on frame 33 by its ends so as to leave a free space 34 between girder 35 and frame 33 through which the overall wide of the split web arrives onto the segmented vacuum roll. A driving apparatus 36a mounted on girder 35 is provided for driving sleeve tube 2a in rotation. A motor (not shown) is fixed on girder 35. An arm 40a extending towards the segmented vacuum roll and slightly downwards is articulated on girder 35. A friction roller 38a is rotatably mounted on the free end of arm 40a. Friction roller is driven by a motor (not shown) mounted on girder 35 through a driving belt device 39a. A pneumatic cylinder 37a the housing of which is rotatably mounted on girder 35 has its rod rotatably linked on arm 40a. Thus, pneumatic cylinder allows friction roller 38a to engage or disengage sleeve tube 2a. As a result, friction roller 38a allows to drive in rotation sleeve tube 2a. Four other driving apparatuses (not shown) similarly designed are mounted on girder 35 in spaced relationship for driving in rotation respectively sleeve tube 2b, 2c, 2d and 2e. As a result, each segment la, lb, lc, Id and le of the segmented vacuum roll is driven by a respective motor and so, may rotate at an own speed. However, this segmented vacuum roll may also be used for driving one large web extending, for instance, from segment la to segment le due to the fact that all sleeve tubes 2a, 2b, 2c, 2d and 2e have the same outer diameter and are aligned. Alternately, it is also possible to use a respective external belt drive instead of friction rollers for driving each sleeve 2a, 2b, 2c, 2d and 2e. To drive each of sleeves 2a. 2b, 2c, 2dand 2e, it is also possible to use a respective gear transmission arranged internally to the sleeve tubes 2a, 2b, 2c, 2d and 2e; in this case, it may be gears with built-in motors or gears coupled to motors arranged externally, on the ends of the segmented vacuum roll via shafts. Alternately, there might be no driving means at all for driving sleeves 2a, 2b, 2c, 2d and 2e. The segmented vacuum roll behaves then as an idle segmented vacuum roll: thus, sleeves 2a, 2b, 2c, 2d and 2e are driven by their respective webs. In the described embodiment, each sleeve tube 2a, 2b, 2c, 2d and 2e has a diameter of 540 mm and a length of about 1 100 mm, thus the overall length of the segments is about 5500 mm. Of course, these sizes may be changed. The inner assembly is preferably made of steel material. The invention was described in reference to a preferred embodiment. However, many variations are possible within the scope of the invention. For instance, inner tube 3 may be not cylindrical as well as the outer tubes 5a, 5b, 5c, 5d and 5e. The number of walls between inner tube 3 and outer tubes 5a, 5b, 5c, 5d and 5e may be varied, depending in particular on the number of channels wished for transmitting vacuum to respective segments. Similarly, the several channels (for transmitting vacuum to respective segments) formed between the walls as well as the inside of inner tube 3 may be defined differently and connected to other segments by distributing differently the holes in the separator disks 4b, 4c, 4d and 4e or placing differently separator disks 7a and 7b inside of inner tube 3. Also, further separator disks may be arranged inside of inner tube 3. It is easy to vary the number of independent segments of the segmented vacuum roll by varying the number of channels for transmitting vacuum.

Claims: CLAIMS 1. A segmented vacuum roll comprising: an inner assembly on which a plurality of cylindrical sleeve tubes (2a, 2b, 2c, 2d, 2e) having apertures over their circumference are rotatably and coaxially mounted side by side, each of said sleeve tubes being individually rotatable; one or several first chambers (9a, 9b, 9c, 9d, 9e) formed in said inner assembly and partly defined by a first portion of circumference of said sleeve tubes, said inner assembly comprising linking means (6a, 6b, 6c, 6d, 6e. 24) for linking a vacuum source to said chambers so that said first portion of circumference of said sleeve tubes may be submitted to vacuum. 2. The segmented vacuum roll according to claim 1, characterized in that each of said sleeve tubes (2a, 2b, 2c, 2d, 2e) corresponds to a respective one of said first chambers (9a, 9b, 9c, 9d, 9e). 3. The segmented vacuum roll according to claim 1 or 2, characterized in that said linking means (6a, 6b, 6c, 6d, 6e, 24) allow to link a respective vacuum source to each of said first chambers. 4. The segmented vacuum roll according to any one of claims 1 to 3, characterized in that said first portion of circumference corresponds to about an angular sector of 90°. 5. The segmented vacuum roll according to any one of claims 1 to 4, characterized in that, for one or both of said sleeve tubes located at the extremity of said vacuum roll, adjustable means (29a, 30a, 30a', 31a, 29e, 30e, 30e', 31e) prevent a longitudinal portion of selectable length at the free extremity of said sleeve tube from being submitted to vacuum. 6. The segmented vacuum roll according to any one of claims 1 to 5, characterized in that at least one second chamber (21a, 21b, 21 c, 2 Id, 21e) is formed in said inner assembly and partly defined by a second portion of circumference of said sleeve tubes (2a, 2b, 2c, 2d, 2e), said inner assembly comprising means (28a, 28b, 28c, 28d, 28e) for linking said second chamber to an air generator so that air may be blown through the perforations of said second portion of circumference of said sleeve tubes. 7. The segmented vacuum roll according to claim 6, characterized in that said second portion of circumference of said sleeve tubes (2a, 2b, 2c, 2d, 2e) is located immediately after said first portion of circumference of said sleeve tubes. 8. The segmented vacuum roll according to any one of claims 1 to 7, characterized in that said inner assembly comprises an inner tube (3), at least one outer tube (5a, 5b, 5c, 5d. 5e) surrounding said inner tube and a plurality of longitudinal walls (l Oa-e, 1 la-e, 12a-e, 13a-e, 14a-e, 15a-e) extending between said inner tube and said outer tube so as to form longitudinal channels (6a, 6b, 6c, 6d, 6e) making part of said linking means. 9. The segmented vacuum roll according to claim 8, characterized in that at least one of said longitudinal channels is subdivided in at least two channels (6a, 6e; 6b, 6d) by at least one radial separation (7a, 7b; 4c, 4d). 10. The segmented vacuum roll according to claim 8 or 9, characterized in that a portion of the circumference of said outer tube (2a, 2b, 2c, 2d, 2e) is omitted so that the cross section of said first chambers (9a, 9b, 9c, 9d, 9e) is defined by a portion of said inner tube (3), two (lOa-e, 15a-e) of said longitudinal walls (l Oa-e, 1 la-e, 12a-e, 13a-e, 14a-e, 15a-e), and said first portion of circumference of said sleeve tubes (2a, 2b, 2c. 2d, 2e). 11. The segmented vacuum roll according to any one of claims 8 to 10, characterized in that a portion of the circumference of said outer tube (5a, 5b, 5c, 5d, 5e) is omitted so that the cross section of said second chambers (21a, 21b, 21c, 2 Id, 21 e) is defined by a portion of said inner tube (3), two (14, 15) of said longitudinal walls (lOa-e 11a- e, 12a-e, 13a-e, 14a-e, 15a-e), and said second portion of circumference of said sleeve tubes (2a, 2b, 2c, 2d, 2e). 12. The segmented vacuum roll according to anyone of claims 8 to 11, characterized in that, for at least one (9a; 9e) of said first chambers (9a, 9b, 9c, 9d, 9e), the corresponding linking means (6a; 6e) comprise an inner end portion of said inner tube (3). 13. The segmented vacuum roll according to anyone of claims 8 to 12, characterized in that, for at least one (9b; 9d) of said first chambers (9a, 9b, 9c, 9d, 9e), the corresponding linking means comprise one (6b; 6d) of said longitudinal channels (6b, 6c, 6d) formed between said inner tube (3) and said outer tube (5a, 5b, 5c, 5d, 5e), and separated from said first chamber by at least one (10a; lOe) of said longitudinal walls (lOa-e l la-e, 12a-e, 13a-e, 14a-e, 15a-e), at least one hole (18a; 18e) being arranged in said longitudinal wall allowing vacuum communication between said longitudinal channel and said first chamber. 14. The segmented vacuum roll according to anyone of claims 8 to 13, characterized in that, for at least one (9c) of said first chambers (9a, 9b, 9c, 9d, 9e), the corresponding linking means comprise an inner portion (24) of said inner tube (3) and one (6c) of said longitudinal channels (6b, 6c, 6d) formed between said inner tube (3) and said outer tube (5a, 5b, 5c, 5d, 5e), said first chamber being in vacuum communication with said longitudinal channel via said inner portion of said inner tube 15. The segmented vacuum roll according to anyone of claims 1 to 14, characterized in that said sleeve tubes (2a, 2b, 2c, 2d, 2e) have the same outer diameter. 16. The segmented vacuum roll according to anyone of claims 1 to 15, characterized in that it further comprises driving means (38a, 39a) for driving in rotation each of said sleeve tubes (2a, 2b, 2c, 2d, 2e) independently from one another. 17. The segmented vacuum roll according to claim 16, characterized in that, for at least one of said sleeve tubes (2a, 2b, 2c, 2d, 2e), said driving means comprise a friction roller (38a) external to said sleeve tubes.

Inventors: MARNACH JOS, NICOLAI LUC MARIE HUBERT ANDRE, PETITJEAN GILLES, MARNACH, JOS, NICOLAI, LUC, MARIE, HUBERT, ANDRE, PETITJEAN, GILLES
Applicants: DU PONT, MARNACH JOS, NICOLAI LUC MARIE HUBERT ANDRE, PETITJEAN GILLES, E.I. DU PONT DE NEMOURS AND COMPANY, MARNACH, JOS, NICOLAI, LUC, MARIE, HUBERT, ANDRE, PETITJEAN, GILLES
Application year: 2000
Main classification: B65H20
IPC codes: B65H20, B65H23