US20080060747A1 - Paper tube and method of making the same - Google Patents

Abstract

An apparatus for manufacturing a paper tube having a polygonal cross section includes a frame, an elongate core assembly having an end rotatably supported to the frame and the other free end and having an outer peripheral surface of a predetermined polygonal shape, and a delivery member installed to the core assembly for at least a portion of the delivery member to be exposed from the outer peripheral surface of the core assembly on which the strips are wound, the delivery member being installed for the exposed portion to move toward the free end of the core assembly after receiving the power, whereby the exposed portion contacts with an inner surface of the lowermost one of a plurality of the strips and thus a plurality of the strips wound on the core assembly continuously move toward the free end of the core assembly.

Description

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
• This application is a continuation application under 35 U.S.C. § 365(c) of International Application No. PCT/KR2006/001664, filed May 3, 2006 designating the United States. International Application No. PCT/KR2006/001664 was published in English as WO2006/121253 A1 on Nov. 16, 2006. This application further claims the benefit of the earlier filing date under 35 U.S.C. § 365(b) of Korean Patent Application No. 10-2005-0039872 filed May 12, 2005. This application incorporates herein by reference the International Application No. PCT/KR2006/001664 including the International Publication No. WO2006/121253 A1 and the Korean Patent Application No. 10-2005-0039872 in their entirety.
BACKGROUND
• 1. Field
• The present disclosure relates to paper tubes, and more particularly, to paper tubes with a corrugated paper layer, method of making of paper tubes, machines for making paper tubes.
• 2. Discussion of the Related Technology
• References which disclose paper tubes are as follows: International Publication No. WO 97/13695, published on Apr. 17, 1997, entitled “METHOD AND DEVICE FOR PRODUCTION OF TUBES”; Korean Patent Laid-Open Publication No. 10-2002-0038467, published on May 23, 2002, entitled “POLYGONALLY WRAPPED PAPER PIPE MAKING MACHINE”; U.S. Pat. No. 4,120,323, issued on Oct. 17, 1978, entitled “POLYGONALLY WRAPPED SLEEVE AND METHODS AND DEVICES FOR MAKING SAME”; Japanese Patent Laid-Open Publication No. (Sho) 50-91808, published on July 22, 1975, entitled “METHOD OF MAKING POLYGONALLY WRAPPED PAPER TUBE”.
• Instead of a pallet made from used wood or synthetic resin, a pallet made of paper has been recently developed and used in the transport of freight. In general, a paper pallet comprises an upper plate on which freight is placed, and a support member which is attached to a lower surface of the upper plate to support the upper plate. As a support member of a paper pallet, a paper tube having a quadrangular cross section is widely used.
• Methods and apparatuses for manufacturing a paper tube having a quadrangular cross section are disclosed in International Publication No. WO 97/13695, Korean Patent Laid-Open Publication No. 2002-0038467 and Japanese Patent Publication Laid-Open No. (Sho) 50-91808. The apparatus for manufacturing a polygonally wrapped paper tube disclosed in the aforementioned patent documents causes a plurality of paper strips previously coated with adhesive to be supplied to a rotating core having a quadrangular cross section and to be wound on an outer peripheral surface of the core. The apparatus is also provided with a plurality of rollers rotating about a rotational axis of the core at the same angular velocity as the core, wherein the plurality of rollers press the strips wound on the outer peripheral surface of the core and simultaneously rotate in a longitudinal direction of the core (rotate about the rotational axis perpendicular to the longitudinal direction of the core). That is, the apparatus for manufacturing a polygonally wrapped paper tube uses the principle that when a plurality of the rollers rotate in the longitudinal direction of the core while pressing the strips (paper tube) wound on the core, the paper tube wound on the core is separated from the core and discharged in the longitudinal direction of the core if a friction force generated between the rollers and an outside surface of the paper tube is greater than that generated between the core and an inside surface of the paper tube.
• According to a method for manufacturing a quadrangularly wrapped paper tube disclosed in U.S. Pat. No. 4,120,523, a quadrangularly wrapped paper tube is manufactured by successively forming a circularly wrapped paper tube, which is continuously formed and discharged, to have a quadrangular cross section using a plurality of forming rollers.
• The foregoing discussion is to provide general background information, and does not constitute an admission of prior art.
SUMMARY
• One aspect provide a tube comprising a hollow polygonal cross-sectional body of a plurality of layers, which may comprise at least one corrugated paper layer, wherein at least one of the plurality of layers may comprise at least one continuous paper band that is spirally arranged so as to define a polygonal cross-section.
• In the foregoing tube, the at least one corrugated paper layer may comprise at least one continuous corrugated paper band that is spirally arranged so as to define a polygonal cross-section. Each continuous corrugated paper band may comprise a non-corrugated paper band and a corrugated paper structure bonded onto the non-corrugated paper band. Each corrugated paper layer may extend free of a substantial gap between two neighboring portions of the continuous corrugated paper band. The plurality of layers may comprise an inner-most layer, an outer-most layer, and at least one intermediate layer, wherein the at least one intermediate layer may comprise the at least one corrugated paper layer. The at least one of the inner-most layer and the outer-most layer does not comprise a corrugated paper band. Each layer may comprise a paper material.
• Still in the foregoing tube, the plurality of layers may comprise a non-corrugated paper layer comprising a non-corrugated continuous paper band that is spirally arranged so as to define a polygonal cross-section, wherein a portion of the continuous, non-corrugated paper band may be overlapping with another portion of the continuous, non-corrugated paper band in the spiral arrangement, wherein the overlapping portions may be glued together. Each corrugated paper layer may comprise a continuous corrugated paper band that is spirally arranged so as to define a polygonal cross-section, wherein the continuous corrugated paper band does not comprise portions that are overlapping with each other in the spiral arrangement.
• Another aspect of the invention provides an article comprising a tubular body extending in a longitudinal direction, wherein the tubular body has a polygonal cross-section in a plane generally perpendicular to the longitudinal direction, wherein the tubular body may comprise a first layer and a second layer, wherein the second layer may comprise a continuous paper band that is spirally arranged around the first layer, wherein at least one of the first and second layers may comprise corrugated paper.
• In the foregoing article, the article may further comprise a plurality of additional tubular body arranged together so as to form a pallet. The first layer may be the inner-most layer of the tubular body and may comprise a continuous paper band that is spirally arranged so as to define a polygonal cross-section. The first layer does not comprise the corrugated paper. The second layer may comprise a continuous corrugated band that is spirally arranged so as to define a polygonal cross-section around the first layer, wherein the continuous corrugated band may comprise a continuous, non-corrugated band and the corrugated paper, which is bonded onto the continuous, non-corrugated band. The second layer may extend substantially free of a gap between two neighboring portions of the continuous corrugated band. The tubular body may further comprise a third layer interposed between the first and second layers, wherein the third layer may comprise the corrugated paper.
• Still another aspect of the invention provides a method of making a hollow tube, which comprise: spirally winding a plurality of bands around at least one rotating shaft so as to form a tubular body comprising a plurality of layers around the at least one shaft, wherein the tubular body may comprise an inner surface; frictionally engaging the inner surface with a friction surface movable in the tubular body; and moving the friction surface so as to transfer the tubular body in a longitudinal direction thereof.
• In the foregoing method, frictionally engaging and moving may occur substantially simultaneously. Frictionally engaging and moving occurs substantially continuously. The friction surface may be part of a conveyor belt, a roller or a lead screw driven by a dedicated power source therefor. The at least one shaft may comprise a plurality of edges extending in the longitudinal direction, wherein the plurality of bands may be winding around the plurality of edges such that the tubular body has a polygonal cross-section. The method may further comprise cutting the tubular body transferred away from the friction surface, wherein prior to cutting, the method does not comprise substantially changing the polygonal cross-sectional shape of the tubular body. The tubular body may be continuously moving generally in the longitudinal direction such that the plurality of bands are wound around a substantially identical portion of the at least one shaft. The plurality of bands may comprise at least one corrugated paper band so as to form at least one corrugated paper layer.
• An aspect of the present invention is to provide a method and apparatus for manufacturing a polygonal paper tube, wherein a thick paper tube having high strength can be produced and its productivity can also be improved since it is possible to continuously produce the paper tube by helically winding strips on a core to overlap each other. Another aspect of the present invention is to provide a method and apparatus for producing a polygonal paper tube using corrugated cardboard strips. A further aspect of the present invention is to provide a polygonal paper tube having superior strength produced according to the foregoing method. An aspect of the present invention provides a method for manufacturing a paper tube having a polygonal cross section. The method for manufacturing a paper tube having a polygonal cross section comprises steps of winding a plurality of paper strips on an outer peripheral surface of a rotating core having a polygonal cross section to be helically overlapped, the paper strips except the lowermost strip being previously coated with adhesive; and delivering continuously a plurality of the paper strips wound on the core in a longitudinal direction of the core by bring a delivery member into contact with an inner surface of the lowermost strip wound on the outer peripheral surface of the core, the delivery member having at least a portion continuously exposed from the outer peripheral surface of the core on which the strips are wound, the delivery member being installed in the core to move in the longitudinal direction of the core.
• The method for manufacturing a paper tube according to embodiments of the present invention does not discharge a paper tube from a core by pressing an outside surface of the paper tube formed by winding strips on the core as in an exemplary method for manufacturing a polygonal paper tube, but is an originative method in that a paper tube helically overlapped and wound on a core is continuously separated from the core by causing a delivery member, which is brought into contact with an inside surface of paper tube formed by winding strips on the core, to continuously move toward a free end of the core.
• In order to easily separate the paper tube from the core, in the method for manufacturing a paper tube according to embodiments of the present invention, it is also preferred that the step of delivering be performed while an upper surface of a plurality of the wound strips corresponding to a position with which the delivery member is brought into contact is pressed with a pressing means at the same time, the pressing means being installed to a frame and rotating at the same angular velocity as the core. As the delivery member used in the method of embodiments of the present invention, delivery belts, delivery gears, or delivery screws may be used. The delivery member is installed in the core so that a portion of the delivery member is exposed from the outer peripheral surface of the core and moves in the longitudinal direction of the delivery member.
• An aspect of the present invention, there is provided an apparatus for manufacturing a paper tube having a polygonal cross section. The apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention comprises a frame; an elongate core assembly having an end rotatably supported to the frame and the other free end to helically overlap and wind a plurality of paper strips on an outer peripheral surface of the core assembly, the paper strips except the lowermost strip being previously coated with adhesive, the outer peripheral surface of the core assembly having a predetermined polygonal shape; a first driving means for providing power for rotating the core assembly; a first power transmitting means for transmitting the power of the first driving means to the core assembly after receiving the power; a delivery member installed to the core assembly for at least a portion of the delivery member to be exposed from the outer peripheral surface of the core assembly on which the strips are wound, the delivery member being installed for the exposed portion to move toward the free end of the core assembly after receiving the power, whereby the continuously exposed portion is brought into contact with an inner surface of the lowermost one of a plurality of the strips wound on the outer peripheral surface of the core assembly and thus a plurality of the strips wound on the core assembly continuously move toward the free end of the core assembly; a second driving means for providing power for causing the portion of the delivery member to be continuously exposed from the outer peripheral surface of the core assembly; and a second power transmitting means for transmitting the power of the second driving means to the delivery member after receiving the power.
• As the core assembly rotates, the delivery member installed to the core assembly causes the lowermost paper strip of a plurality of the paper strips helically wound on the outer peripheral surface to move toward the free end of the core assembly. Contrary to an apparatus disclosed in the references discussed above, which causes an inner peripheral surface of a paper tube to be slid and discharged from a core by pressing an outer peripheral surface of the wound paper tube with rollers, the apparatus for manufacturing a polygonal paper tube according to embodiments of the present invention causes the delivery member to be brought into contact with the inner peripheral surface of the wound polygonal paper tube and to push and discharge the paper tube toward the free end of the core, so that a friction force between the core and the polygonal paper tube is small and thus it is possible to manufacture a thicker paper tube. That is, a paper tube is manufactured by discharging a plurality of paper strips (paper tube) wound on the outer peripheral surface of the core assembly toward the free end of the core assembly by a friction force generated when a portion of the delivery member which is continuously exposed from the outer peripheral surface of the core assembly is brought into contact with the inside surface of the lowermost paper strip.
• Also, the apparatus for manufacturing a paper tube according to embodiments of the present invention can advantageously manufacture a polygonal paper tube using one-sided corrugated cardboard strips. Since an apparatus disclosed in the references discussed above presses an outer peripheral surface of paper strips wound on a core, if one-sided corrugated cardboard strips are used when a polygonal paper tube is manufactured, corrugations of the corrugated cardboard strips are damaged and thus it is impossible to use corrugated cardboard strips. However, in the apparatus for manufacturing a polygonal paper tube according to embodiments of the present invention, a portion of the delivery member which is installed in the core assembly and continuously exposed from the outer peripheral surface of the core assembly is brought into contact with corrugated cardboard strips wound on the core assembly and pushes the wound paper tube toward the free end of the core assembly to discharge the paper tube from the core assembly, so that corrugations of the corrugated cardboard strips are not damaged.
• Also, in the apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention, the first power transmitting means includes a first hollow rotational shaft rotatably supported to the frame to rotate after receiving the power from the first driving means and formed with a through-hole in a longitudinal direction of the first rotational shaft, and a coupling member having a side connected to the first rotational shaft and the other side connected to the core assembly; and the second power transmitting means includes a second rotational shaft rotatably supported to the first rotational shaft, the second rotational shaft being inserted into the through-hole of the first rotational shaft to rotate after receiving the power from the second driving means, and a third power transmitting means for transmitting the rotational power of the second rotational shaft to the delivery member. That is, the first rotational shaft for transmitting the power of the driving means (motor) for rotating the core assembly is formed to be hollow and the second rotational shaft for transmitting the power of the driving means (servo motor) for driving the delivery member is installed to rotate in the hollow of the first rotational shaft, so that it is possible to reduce a size of the apparatus for manufacturing a paper tube and to stably transmit power.
• Also, in the apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention, delivery belts, delivery gears or delivery screws may be used as the delivery member. When delivery belts are used as the delivery member, a pair of delivery belts are installed for portions of the delivery belts to be exposed from opposite portions of the outer peripheral surface of the core assembly along the longitudinal direction thereof, and the exposed portions of the delivery belts are installed to move toward the free end of the core assembly. Also, the third power transmitting means further includes a third rotational shaft rotatably installed to the coupling member to be perpendicular to the second rotational shaft, a pair of bevel gears which are respectively installed on the second and third rotational shafts and meshed with each other to transmit the power of the second rotational shaft to the third rotational shaft, and a fourth power transmitting means for transmitting the rotational power of the third rotational shaft to a pair of the delivery belts.
• When the delivery belts are used as the delivery member, it is possible to increase the strength of the delivery member by fixing a pair of delivery guide members for guiding the movement of the delivery belts to a quadrangular rod core of the core assembly. It is also possible to easily change a width of the paper tube to be manufactured by installing the delivery belts to upper and lower cores and controlling a gap between the upper and lower cores.
• In a case where a core assembly is configured using a single quadrangular rod core and delivery guide members, the core assembly comprises an elongate quadrangular rod core with an end fixed to the coupling member and a pair of elongate delivery guide members fixed to both opposite side surfaces of the quadrangular rod core, each of the delivery guide members including a base portion having a width larger than that of the quadrangular rod core and fixed to each of both the side surface of the quadrangular rod core and upper and lower guide wing portions protruding in parallel from both widthwise ends of each base portion toward the opposite one of the base portions spaced apart from each other and extending by a predetermined length in the longitudinal direction of the delivery guide member; a pair of the delivery belts are installed to be wound on the opposite upper guide wing portions and the opposite lower guide wing portions of a pair of the delivery guide members, respectively; and the fourth power transmitting means includes upper and lower belt driving shafts which are rotatably installed to the fixed end of the quadrangular rod core of the core assembly and on which the upper and lower delivery belts are respectively wound, upper and lower idle rollers which are rotatably installed to the free ends of the delivery guide members of the core assembly to be spaced apart from each other and on which the upper and lower delivery belts are respectively wound, and gears for transmitting the power of the third rotational shaft to the upper and lower belt driving shafts.
• In a case where a core assembly is configured using upper and lower cores, the core assembly comprises an elongate upper core with an end fixed to the coupling member and an elongate lower core with an end fixed to the coupling member, the lower core being spaced apart by a predetermined distance from the upper core; a pair of the delivery belts are installed to be wound on the upper and lower cores in the longitudinal direction, respectively; the fourth power transmitting means includes upper and lower belt driving shafts which are rotatably installed to the fixed ends of the upper and lower cores and on which the upper and lower delivery belts are wound, respectively, upper and lower idle rollers which are rotatably installed to the free ends of the upper and lower cores and on which the upper and lower delivery belts are wound, respectively, and a power transmitting means for transmitting the power of the third rotational shaft to the upper and lower belt driving shafts, respectively.
• In a case where delivery gears are used as the delivery member, at least a pair of delivery gears are installed to be rotatable about a rotational shaft installed perpendicular to the longitudinal direction of the core assembly and are installed for portions of the delivery gears to be exposed from opposite portions of the outer peripheral surface of the core assembly. Also, the third power transmitting means further includes a third rotational shaft rotatably installed to the coupling member to be perpendicular to the second rotational shaft, a pair of bevel gears which are respectively installed on the second and third rotational shafts and meshed with each other to transmit the power of the second rotational shaft to the third rotational shaft, and a fifth power transmitting means for transmitting the rotational power of the third rotational shaft to a pair of the delivery gears.
• When delivery screws are used as the delivery member, an end of each delivery screw is rotatably installed to the coupling member for a portion of the delivery screw to be exposed from the outer peripheral surface of the core assembly in the longitudinal direction thereof, and the other end of each delivery screw is rotatably installed to the core assembly. Also, the third power transmitting means includes a driving gear installed to the second rotational shaft, and a plurality of driven gears fixedly installed to the ends of the delivery screws to be meshed with the driving gear, respectively.
• In addition, the apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention further comprises a means for preventing the free end of the core assembly from vibrating in order to operate the apparatus safely, for discharging a paper tube to the free end of the core assembly without slip, and for keeping a discharged paper tube to have a polygonal shape. The apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention further comprises a fourth hollow rotational shaft installed to be supported to the frame and to rotate at the same angular velocity as the core assembly, the fourth rotational shaft being formed with a through-hole through which the paper tube of a plurality of the wound strips passes, the paper tube being discharged toward the free end of the core assembly, and a pressing means fixed to the fourth hollow rotational shaft to symmetrically press an upper surface of the uppermost one of a plurality of the strips wound on the free end of the core assembly. Preferably, the pressing means is supported by an elastic member to press the paper tube at constant pressure.
• Also, the apparatus for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention further comprises a paper tube cutting means for cutting the paper tube continuously manufactured and discharged toward the free end of the core assembly by an appropriate length. The paper tube cutting means includes a base installed to the frame to be movable in the longitudinal direction of the core assembly, and a cutter installed to the base to be movable in the direction perpendicular to the longitudinal direction of the core assembly. Preferably, a rotating circular cutter or a saw blade is used as the cutter. In addition, the paper tube cutting means further comprises a fourth hollow rotational shaft installed to be supported to the base and to rotate at the same angular velocity as the core assembly and formed with a through-hole through which the paper tube of a plurality of the wound strips passes, the paper tube being discharged toward the free end of the core assembly.
• A further aspect of the present invention provides a paper tube manufactured by the method for manufacturing a paper tube having a polygonal cross section according to embodiments of the present invention. Particularly, in the paper tube manufactured by the method according to embodiments of the present invention, a plurality of paper strips used for manufacturing a paper tube preferably includes at least a one-sided corrugated cardboard strip.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of an apparatus for manufacturing a paper tube having a polygonal cross section according to an embodiment of the present invention.
• FIG. 2 is a plan view illustrating a state where a plurality of paper strips are wound around the paper tube manufacturing apparatus shown inFIG. 1.
• FIG. 3 is a sectional view taken along line A-A ofFIG. 2.
• FIG. 4 is a sectional view taken along line C-C ofFIG. 3.
• FIG. 5 is a sectional view taken along line D-D ofFIG. 3.
• FIG. 6 is a sectional view taken along line E-E ofFIG. 3.
• FIG. 7 is a sectional view taken along line F-F ofFIG. 3.
• FIG. 8 is a sectional view taken along line I-I ofFIG. 3.
• FIG. 9 is a sectional view taken along line H-H ofFIG. 3.
• FIG. 10 is a sectional view taken along line B-B ofFIG. 3.
• FIG. 11 is a sectional view taken along line J-J ofFIG. 10.
• FIG. 12 is a perspective view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to another embodiment of the present invention.
• FIG. 13 is a plan view of an embodiment shown inFIG. 12.
• FIG. 14 is a front view of an embodiment shown inFIG. 12.
• FIG. 15 is a schematic view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to a further embodiment of the present invention.
• FIG. 16 is a sectional view taken along line Q-Q ofFIG. 15.
• FIG. 17 is a sectional view taken along line R-R ofFIG. 15.
• FIG. 18 is a sectional view taken along line S-S ofFIG. 15.
• FIG. 19 is a schematic view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to an embodiment of the present invention.
• FIG. 20 is a sectional view taken along line N-N ofFIG. 19.
• FIG. 21 is a sectional view taken along line P-P ofFIG. 19.
• FIG. 22 is an exemplary view illustrating a state where a polygonal paper tube is manufactured using one-sided corrugated cardboard strips.
DETAILED DESCRIPTION OF EMBODIMENTS
• Various embodiments of the invention will be described below.
• According to the methods and apparatuses for manufacturing a quadrangular paper tube, disclosed in all the aforementioned documents and discussed in the foregoing background section, it is difficult to continuously manufacture a polygonal paper tube of a predetermined thickness or more, for example, a quadrangular paper tube of a thickness of at least 5 mm by helically winding the paper tube.
• According to the method for manufacturing a polygonal paper tube by winding a plurality of paper strips on a rotating polygonal core and then pressing an outer peripheral surface of the wound paper strips with a plurality of rollers and simultaneously separating the paper tube from the core, discussed in the foregoing background section, when a paper tube is thick, a pressing force of the roller should be significantly great in order to increase a friction force between the rollers and the paper tube. However, since the friction force between the core and an inside surface of the paper tube is increased as the pressing force of the rollers is increased, there is a problem in that it is difficult to separate the paper tube from the core. According to the method for forming a circular paper tube into a quadrangular paper tube, discussed in the foregoing background section, there is a problem in that it is theoretically impossible to make a paper tube having an accurate quadrangular cross section since a perimeter of a circle is not accurately identical to a perimeter of a quadrangle. Further, there is a problem in that when a thickness of the paper tube is greater than a predetermined thickness, a gap between the inner wound strip and the outer wound strip is increased and thus the paper tube is distorted while it is formed.
• Furthermore, when the method for manufacturing a polygonal paper tube discussed in the background section is applied to corrugated cardboard strips, the corrugations of the corrugated cardboard strips can be damaged, and thus it is impossible to manufacture a polygonal paper tube using strips of corrugated cardboard strips.
• FIG. 1 is a perspective view of an apparatus for manufacturing a paper tube having a polygonal cross section according to an embodiment of the present invention,FIG. 2 is a plan view illustrating a state where a plurality of paper strips are wound around the paper tube manufacturing apparatus shown inFIG. 1, andFIG. 3 is a sectional view taken along line A-A ofFIG. 2.
• Referring to FIGS.1 to3, anapparatus100 for manufacturing a paper tube having a polygonal cross section according to the present embodiment comprises aframe10, acore assembly20 having an end rotatably supported to theframe10 and the other free end, a delivery member for continuously moving a plurality of paper strips a, b, c, d, e, and f, which are previously coated with adhesive and are helically wound on thecore assembly20 to overlap each other, toward the free end of thecore assembly20. In the present embodiment, the delivery member includes a pair ofdelivery belts71 and72.
• Referring toFIG. 2, thecore assembly20 is narrow and elongate and has a quadrangular cross section. When thecore assembly20 rotates with power received from a first driving means30, a plurality of the paper strips a, b, c, d, e, and f are helically wound on an outer circumferential surface of thecore assembly20 to overlap each other, wherein the paper strips except the paper strip a are previously coated with adhesive. InFIG. 2,unexplained reference numeral91 designates an adhesive supply device for coating the strip with adhesive, andreference numeral92 designates an adhesive coating roller. Referring toFIG. 3, theframe10 is equipped with the first driving means30 for providing power needed to rotate thecore assembly20, and a first power transmitting means50 for receiving the power from the first driving means30 and transmitting the received power to thecore assembly20. Further, referring toFIG. 2, theframe10 is equipped with a second driving means40 for providing power to a pair of thedelivery belts71 and72, and a second power transmitting means60 for receiving the power from the second driving means40 and transmitting the received power to a pair of thedelivery belts71 and72. The first and second driving means30 and40 preferably include motors. Particularly, it is more preferably that a servomotor be used as the second driving means to control a discharge velocity of apaper tube200 after receiving a velocity of thepaper tube200 and a rotational velocity of thecore assembly20 as feedback signals.
• Further, in theapparatus100 for manufacturing a paper tube of the present embodiment, a fourthrotational shaft80 is installed to theframe10 so as to rotate at the same angular velocity as thecore assembly20. The fourthrotational shaft80 is formed with a through-hole80athrough which thepaper tube200 passes, wherein thepaper tube200 is continuously discharged toward the free end of thecore assembly20. At an end of the fourthrotational shaft80 which is hollow, there is installed a pressing means83 for pressing the paper tube to prevent the free end of thecore assembly20 from vibrating, to allowing thepaper tube200 to be discharged toward the free end of thecore assembly20 without slip, and to keep the paper tube to be quadrangle-shaped. The pressing means83 is fixed to the fourthrotational shaft80, rotates at the same angular velocity as the fourth rotational shaft, and symmetrically presses opposite side surfaces of thepolygonal paper tube200, which is discharged toward the free end of thecore assembly20 by a pair of thedelivery belts71 and72. In order to transmit the power for rotating the fourth hollowrotational shaft80, to which the pressing means83 is fixed, at the same angular velocity as thecore assembly20, a drivenpulley82 is fixed to an end of the fourth hollowrotational shaft80. Also, in theframe10, atransmission shaft81 for transmitting power to the drivenpulley82 is supported by a pair ofbearings81band81cand connected to the first driving means30. In addition, a drivingpulley81afor transmitting power to the drivenpulley82 is fixed to the end of thetransmission shaft81, and the drivingpulley81aand the drivenpulley82 are connected to each other with atiming belt81d.By appropriately determining diameters of the drivingpulley81aand the drivenpulley82, it is possible for thecore assembly20 and the fourthrotational shaft80 to have the same rotational velocity.
• Referring toFIG. 3, the first power transmitting means50 for receiving power from the first driving means30 and transmitting the power for rotating thecore assembly20 is schematically shown within a dotted line. The first power transmitting means50 includes a first hollowrotational shaft51 rotatably supported to theframe10 by bearings and formed with a through-hole51aand acoupling member52 having a side connected to the firstrotational shaft51 and the other side to which thecore assembly20 is fixed. The firstrotational shaft51, thecoupling member52 and thecore assembly20 are integrally fixed to each other to have the same rotational center, and thus, rotate at the same angular velocity. Apulley53 is fixed to the other end of the first hollowrotational shaft51 and is connected through abelt54 to thepulley55 connected to the rotational shaft of the first driving means30.Unexplained reference numeral56 designates a reducer. When themotor30 rotates, power is transmitted to thecore assembly20 through thepulley55, thebelt54, thepulley53, the firstrotational shaft51, and thecoupling member52, whereby thecore assembly20 rotates. In addition, when themotor30 rotates, the power is transmitted to the pressing means83 through thetransmission shaft81, thepulley81a, thebelt81d,thepulley82, and the fourth hollowrotational shaft80, whereby the pressing means presses thepaper tube200 and at the same time rotates at the same angular velocity as thecore assembly20.
• Referring toFIG. 2, the second power transmitting means60 for transmitting the power for driving a pair of thedelivery belts71 and72 installed to the core assembly after receiving the power from the second driving means40 is schematically shown within a dotted line. Referring toFIG. 3, the second power transmitting means60 includes a secondrotational shaft61 inserted into the through-hole51 a of the firstrotational shaft51 and rotatably supported by bearings and a third power transmitting means for transmitting rotational power of the secondrotational shaft61 to thedelivery belts71 and72. Referring toFIG. 9 which is a sectional view taken along line H-H ofFIG. 3, the third power transmitting means includes a thirdrotational shaft62 rotatably installed to thecoupling member52 to be perpendicular to the secondrotational shaft61, abevel gear63 installed to an end of the secondrotational shaft61 for transmitting the power of the secondrotational shaft61 to the thirdrotational shaft62 arranged to be perpendicular thereto, and abevel gear64 meshed with thebevel gear63 for perpendicularly transmitting the power thereto and installed on the thirdrotational shaft62. In addition, the third power transmitting means includes a fourth power transmitting means for transmitting the power of the thirdrotational shaft62 to a pair of thedelivery belts71 and72 installed to thecore assembly20.
• FIG. 4 is a sectional view taken along line C-C ofFIG. 3. Referring toFIGS. 3 and 4, thecore assembly20 includes an elongatequadrangular rod core21, and a pair of elongatedelivery guide members22 fixed at both opposite side surfaces of thequadrangular rod core21. An end of thequadrangular rod core21 is fixed to thecoupling member52 while the other free end is inserted into the through-hole80aof the fourthrotational shaft80. Each of thedelivery guide members22 is provided with anelongate base portion22bto be fixed to each of both the side surfaces of thequadrangular rod core21, and upper and lowerguide wing portions22aand22cextending from thebase portion22b.Thebase portion22bhas a width larger than that of thequadrangular rod core21 and is fixed to each of both the side surfaces of thequadrangular rod core21 with a plurality ofbolts23. The upper and lowerguide wing portions22aand22cprotrude in parallel from both widthwise ends of eachbase portion22btoward the opposite one of thebase portions22bspaced apart from each other and extend by a predetermined length in a longitudinal direction. The upperguide wing portions22aof a pair of thedelivery guide members22 are wound by theupper delivery belt71 while the lowerguide wing portions22cof a pair of thedelivery guide members22 are wound by thelower delivery belt72.
• Referring toFIGS. 3, 8 and9, the fourth power transmitting means for transmitting the rotational power transmitted to the thirdrotational shaft62 to a pair of thedelivery belts71 and72 includes upper and lowerbelt driving shafts76aand76band upper and loweridle rollers73 and74. The upper and lowerbelt driving shafts76aand76bare rotatably installed at the fixed end of thequadrangular rod core21. The upper and loweridle rollers73 and74 are rotatably installed to be spaced apart by a predetermined length from each other at the free ends of thedelivery guide members22, respectively. The upper and lowerbelt driving shafts76aand76bare installed to a pair ofbrackets26 and27 fixed to thequadrangular rod core21 to be supported by bearings. The annularupper belt71 is wound on the upperbelt driving shaft76a,is guided by the upperguide wing portions22ainserted into theupper belt71, and is wound on the upperidle roller73. In addition, the annularlower belt72 is wound on the lowerbelt driving shaft76b,is guided by the lowerguide wing portions22cinserted into thelower belt72, and is wound on the loweridle roller74. That is, theupper delivery belt71 is wound on the upperbelt driving shaft76aand the upperidle roller73 and the upperguide wing portions22aof thedelivery guide members22 are inserted into both the sides of theupper delivery belt71 while thelower delivery belt72 is wound on the lowerbelt driving shaft76band the loweridle roller74 and the lowerguide wing portions22cof thedelivery guide members22 are inserted into both the sides of thelower delivery belt72, whereby the upper andlower delivery belts71 and72 do not interfere with each other when they rotate.
• In addition,FIG. 8 is a sectional view taken along line I-I ofFIG. 3. Referring toFIGS. 8 and 9, the fourth power transmitting means is provided withgears65,66,67 and68 for respectively transmitting the rotational power of the thirdrotational shaft62 to the upper and lowerbelt driving shafts76aand76b.Although gears, as the power transmitting means, are used in the present embodiment, the belt and pulleys may be used. Thegear65 fixed to an end of the thirdrotational shaft62 is meshed with thegear66 fixed to an end of the lowerbelt driving shaft76b,while thegear67 fixed to the other end of the lowerbelt driving shaft76bis meshed with thegear68 fixed to an end of the upperbelt driving shaft76a.Thus, when thegear65 rotates in one direction, the upper and lowerbelt driving shafts76aand76brotate opposite to each other. Therefore, by properly controlling the rotational direction of thegear65, it is possible to cause the portions of the upper andlower delivery belts71 and72, which the paper strips are wound on and brought into contact with and which are respectively positioned above and below the upper and lowerguide wing portions22aand22cand exposed to the outside, to move toward the free end of the core assembly.
• In the present embodiment, the respective portions of the upper andlower delivery belts71 and72 positioned outside theguide wing portions22aand22care the portions of the delivery member installed to the core assembly such that at least the portions can be exposed from the outer peripheral surface of the core assembly on which the strips are wound. As thedelivery belts71 and72 rotates by means of the received power, the exposed portions of the delivery belts move toward the free end of thecore assembly20. The portions of thedelivery belts71 and72 which move toward the free end, are continuously brought into contact with an inner peripheral surface of thepolygonal paper tube200 which is formed by helically winding a plurality of the paper strips on the outer peripheral surface of thecore assembly20, and cause thepaper tube200 to be discharged to the free end of thecore assembly20.
• Referring toFIG. 3,idle rollers77aand77brotatably installed to thequadrangular rod core21 are movable so as to control tensions of theupper belt71 and thelower belt72, respectively. Anidle roller75 rotatably installed to the free end of thecore assembly20 is to guide the movement of thelower belt72 and control the tension thereof. The movement guidance and tension control of theupper belt71 can be performed by controlling the position of the loweridle roller74.
• FIG. 5 is a sectional view taken along line D-D ofFIG. 3, which illustrates a state where theidle roller75 is rotatably installed to thebase portions22bof thedelivery guide members22 by bearings is shown.FIG. 6 is a sectional view taken along line E-E ofFIG. 3, which illustrates a state where thelower belt72 is wound on the loweridle roller74 that is rotatably installed to thebase portions22bof thedelivery guide members22 by bearings.FIG. 7 is a sectional view taken along line F-F ofFIG. 3, which shows a state where theupper belt71 is wound on the upperidle roller73 that is rotatably installed to thebase portions22bof thedelivery guide members22 by bearings.
• Referring toFIGS. 1, 10 and11, the pressing means83 of the present embodiment include a pair ofidle belts85 installed above and below thecore assembly20 symmetrically to face the exposed surfaces of the upper andlower delivery belts71 and72. A pair of theidle belts85 is wound on a pair ofidle rollers86 and circularly rotates. A pair of theidle rollers86 is installed tobrackets89, and thebrackets89 are installed tohousings87 constrained to be vertically movable by the guide bars84. Although in the present embodiment, theidle belts85 are used for increasing the surface pressure pressing the outside surface of thepaper tube200, rollers or sliding plates may be used. Further, thebracket89 is guided bylinear guides88 fixed to aflange portion80bformed on the other end of the hollow fourthrotational shaft80, and thereby can be vertically controlled. In addition, springs84aare fitted around the guide bars84, so that it is possible to press an upper surface of the formed paper tube at constant pressure.
• Hereinafter, referring toFIGS. 2 and 3, the operation of the apparatus for manufacturing a paper tube according to the present embodiment will be described.
• As shown inFIG. 2, a plurality of the strips are attached on the outer peripheral surface of thecore assembly20 to overlap each other slantly at a constant angle such that the strips except the lowermost strip are previously coated with adhesive. Next, when the motors, which are the first and second driving means30 and40, rotate together at an appropriate velocity ratio, the operation of the first power transmitting means50 causes thecore assembly20 to rotate and simultaneously the operation of the second power transmitting means60 causes the exposed portions of the upper andlower delivery belts71 and72 installed to thecore assembly20 to circularly move toward the free end of thecore assembly20. Thus, a plurality of the paper strips attached on the outer peripheral surface of thecore assembly20 are helically wound thereon and the wound strips (paper tube)200 move simultaneously toward the free end of thecore assembly20 by means of the upper andlower delivery belts71 and72 brought into contact with the lowermost strip. Therefore, the paper tube is continuously formed by causing the strips to be wound and is discharged toward the free end. At this time, if the pressing means installed at a side of the free end presses the upper surface of the paper tube, the friction force between the upper andlower delivery belts71 and72 and the inside surface of the paper tube in contact therewith is increased, so that the friction force assists the paper tube to be discharged smoothly without slip between the delivery belts and the inside surface of the paper tube.
• FIG. 12 is a perspective view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to another embodiment of the present invention,FIG. 13 is a plan view of an embodiment shown inFIG. 12, andFIG. 14 is a front view of an embodiment shown inFIG. 12.
• A core assembly of the present embodiment is different from an embodiment shown inFIG. 1 in that the core assembly of the present embodiment makes it possible to easily control a width of a paper tube to be manufactured by installing delivery belts to upper and lower cores and enabling the gap between the upper and lower cores to be controlled although an embodiment shown inFIG. 1 increases its strength by fixing a pair of the delivery guide members for guiding the movement of the delivery belts to the quadrangular rod core of the core assembly.
• Referring to FIGS.12 to14, acore assembly120 of the present embodiment includes an elongateupper core121 with an end fixed to thecoupling member52 and an elongatelower core122 with an end fixed to thecoupling member52, thelower core122 being spaced apart from theupper core121. In the present embodiment, the fourth power transmitting means for transmitting the rotational power transmitted to the thirdrotational shaft62 shown inFIG. 9 to the upper andlower delivery belts71 and72 includes the upper and lowerbelt driving shafts76aand76band the upper and loweridle rollers73 and74 in the same manner as an embodiment shown inFIG. 1. The upper and lowerbelt driving shafts76aand76bare rotatably installed to the fixed ends of the upper andlower cores121 and122, respectively, and the upper and loweridle rollers73 and74 are rotatably installed to free ends of the upper andlower cores121 and122, respectively. The annularupper belt71 is wound on the upperbelt driving shaft76aand the upperidle roller73, thereby being installed in a conveyor form which winds theupper core121 in its longitudinal direction. The annularlower belt72 is also wound on the lowerbelt driving shaft76band the loweridle roller74, thereby being installed in a conveyor form which winds thelower core122 in its longitudinal direction. In the present embodiment, the power transmitting means for respectively transmitting the rotational power of the thirdrotational shaft62 to the upper and lowerbelt driving shafts76aand76bincludes a pair oftransmission belts167 and168 and a plurality ofpulleys165,166,169 and170. Thepulleys165 and166 are fixed to both ends of the thirdrotational shaft62. Thepulley169 is connected to the lowerbelt driving shaft76b, and thepulley170, which is a medium for switching the rotational direction of theupper delivery belt71, transmits power to the upperbelt driving shaft76athrough agear172 fixed to the upper belt driving shaft and agear171 fixed to thepulley170. That is, in order to cause a portion of theupper delivery belt71 which covers anoutside surface121 a of theupper core121 and a portion of thelower delivery belt72 which covers anoutside surface122aof thelower core122 to move together toward the free end of thecore assembly120, a pair of themeshed gears171 and172 for transmitting power to the upperbelt driving shaft76aby switching the rotational direction of thepulley170 are installed to the upperbelt driving shaft76aand a shaft of thepulley170, respectively.
• In the present embodiment, the portion of theupper delivery belt71 positioned on theoutside surface121aof theupper core121 and the portion of thelower delivery belt72 positioned on theoutside surface122aof thelower core122 are the portions of the delivery member installed to the core assembly such that at least the portions can be exposed from the outer peripheral surface of the core assembly on which the strips are wound. As thedelivery belts71 and72 receive power to rotate, the exposed portions of thedelivery belts71 and72 move toward the free end of thecore assembly120. Thedelivery belts71 and72 are continuously brought into contact with the inner peripheral surface of thepolygonal paper tube200 which is formed by helically winding a plurality of the paper strips on the outer peripheral surface of thecore assembly120, and cause thepaper tube200 to be delivered toward the free end of thecore assembly120.
• Also, the apparatus for manufacturing a paper tube of the present embodiment makes it possible to control the gap between theupper core121 and thelower core122 fixed to thecoupling member52, whereby it is possible to change the width of a paper tube to be manufactured. That is, thecoupling member52 is equipped with linear guides153, and theupper core121 and thelower core122 are respectively fixed to a pair ofbrackets154 and155 movably installed to the linear guides153.
• In addition, the apparatus for manufacturing a paper tube of the present embodiment further comprises a paper tube cutting means130 for cutting the paper tube continuously discharged toward the free end of thecore assembly120 by an appropriate length. The paper tube cutting means130 comprises a base131 installed to theframe10 to be movable in the longitudinal direction of thecore assembly120, and acutter132 installed to the base to be movable in the direction perpendicular to the longitudinal direction of thecore assembly120. Theframe10 is mounted with amotor146 for providing the power for moving thebase131 and a pair oflinear guides144 for guiding the movement of thebase131. When the paper tube is cut, thebase131 is caused to move at the same velocity as the discharge velocity of the paper tube by aball screw145 installed on a shaft of themotor146.
• Further, thebase131 is mounted with abed133 for moving thecutter132 in the direction perpendicular to the discharge direction of the paper tube, and thebed133 is mounted with vertical delivery guides140. Adelivery plate139 is mounted to the guides and thus is installed on an upper portion of thebed133, and thecutter132 and amotor134 for driving thecutter132 are installed to an upper portion of thedelivery plate139. Thecutter132 and themotor134 are installed to thedelivery plate139, which is provided with linear guides to minutely move in the discharge direction of the paper tube when the paper tube is cut. As shown in the figure, it is preferred that a rotating circular cutter or a saw blade be used as thecutter132.
• In addition, the paper tube cutting means130 is supported to thebase131, is installed so as to rotate at the same angular velocity as thecore assembly120, and further includes a fourth hollowrotational shaft146 formed with a through-hole146athrough which the paper tube discharged toward the free end of thecore assembly120 passes. Although not shown, the fourth rotational shaft is equipped with a device for gripping the paper tube the end of which is pushed by the cutter when the discharged paper tube is cut.
• Since the operation of the apparatus for manufacturing a paper tube of the present embodiment is identical to that of the operation of the apparatus for manufacturing a paper tube of an embodiment shown inFIG. 1 except that the paper tube cutting means130 cuts the paper tube discharged toward the free end of thecore assembly120 in the present embodiment, the description of the operation of the present embodiment will be omitted.
• FIG. 15 is a schematic view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to a further embodiment of the present invention,FIG. 16 is a sectional view taken along line Q-Q ofFIG. 15,FIG. 17 is a sectional view taken along line R-R ofFIG. 15, andFIG. 18 is a sectional view taken along line S-S ofFIG. 15.
• The apparatus for manufacturing a paper tube according to one embodiment of the present invention is different from the apparatus for manufacturing a paper tube shown inFIG. 1 in that delivery gears79a,79b,79dand79einstalled acore assembly20 are used as the delivery member for a paper tube. Thecore assembly20 of the present embodiment includes an elongatequadrangular rod core21 with an end fixed to acoupling member52 and a pair of elongatedelivery guide members22 fixed to both opposite side surfaces of thequadrangular rod core21. Each of thedelivery guide members22 includes abase portion22bwider than thequadrangular rod core21 and fixed to each of both the side surfaces of thequadrangular rod core21 and upper and lowerguide wing portions22aand22cprotruding in parallel from both widthwise ends of eachbase portion22btoward the opposite one of thebase portions22bspaced apart from each other and extending by a predetermined length in a longitudinal direction. A pair of the delivery gears79aand79bis rotatably installed to the free ends of thedelivery guide members22 where theguide wing portions22aand22care removed so that addendum circles of the gears protrude upward from thedelivery guide members22. Agear79cis a transmission gear for transmitting power to a pair of the delivery gears79dand79eadjacent thereto.
• A power transmitting means for transmitting the rotational power of the thirdrotational shaft62 shown inFIG. 9 to the delivery gears79aand79bincludes abelt driving shaft76 rotatably installed to the fixed end of thequadrangular rod core21, a gear, not shown, for transmitting the rotational power of the thirdrotational shaft62 to thebelt driving shaft76, a belt drivenshaft77 installed to the free end of thecore assembly20, abelt75 for connecting thebelt driving shaft76 and the belt drivenshaft77 to each other, and agear78 fixed to the belt drivenshaft77 and installed to be meshed with thedelivery gear79a.
• In the present embodiment, the addendum circle portions of the respective delivery gears79a,79b,79cand79dwhich protrude outward from thedelivery guide members22 are the portions of the delivery member installed to the core assembly such that at least the portions can be exposed from the outer peripheral surface of the core assembly on which the strips are wound. As thedelivery gear79a,79b,79cand79dreceive the power of thebelt75 to rotate, the addendum circle portions thereof which protrude outward from thedelivery guide members22 move toward the free end of thecore assembly20. The addendum circle portions are continuously brought into contact with an inner peripheral surface of the polygonal paper tube which is formed by helically winding a plurality of the paper strips on the outer peripheral surface of thecore assembly20, and cause thepaper tube200 to move toward the free end of thecore assembly20.
• FIG. 19 is a schematic view illustrating an apparatus for manufacturing a paper tube having a polygonal cross section according to an embodiment of the present invention,FIG. 20 is a sectional view taken along line N-N ofFIG. 19,FIG. 21 is a sectional view taken along line P-P ofFIG. 19.
• The apparatus for manufacturing a paper tube of the present embodiment is different from the apparatus for manufacturing a paper tube shown inFIG. 1 in that delivery screws installed to thecore assembly20 are used as the delivery member of the paper tube in the present embodiment.
• Referring toFIGS. 19 and 20, acore assembly320 according to this embodiment includes an elongatequadrangular rod core321 having an end fixed to thecoupling member52 and the other free end. Four corner portions of thequadrangular rod core321 are removed by a predetermined length along its longitudinal direction from the portion where thequadrangular rod core321 is connected to thecoupling member52. In addition, the delivery screws322,323,324 and325 are respectively inserted into the four removed corner portions of thequadrangular rod core321 and are installed such that portions of outer peripheral surfaces of the delivery screws are exposed to the outside. One ends of the delivery screws are rotatably installed to thecoupling member52 and the other ends thereof are rotatably installed to the non-removed portions of thequadrangular rod core321. Although not shown, the outer peripheral surfaces of the respective delivery screws322,323,324 and325 are formed with threads. Referring toFIG. 21, drivengears326,327,328 and329 are fixed to the ends of the delivery screws322,323,324 and325 which are fixed to thecoupling member52, respectively. Adriving gear61afixed to an end of the secondrotational shaft61 is installed at the center of the driven gears to be meshed therewith. A pressing means383 of the apparatus for manufacturing a paper tube of the present embodiment is also different from the pressing means83 of an embodiment shown inFIG. 1 in that the pressing means383 of the present embodiment usestapered rollers384 for pressing corner portions of the paper tube.
• In the present embodiment, the threads which are formed on the outer peripheral surfaces of the delivery screws322,323,324 and325 rotatably installed to the removed corner portions of thequadrangular rod core321 and brought into contact with an inner peripheral surface of the paper tube are the portions of the delivery member installed to the core assembly such that at least the portions can be exposed from the outer peripheral surface of the core assembly on which the strips are wound. As the delivery screws322,323,324 and325 receive the power from thedriving gear61ato rotate, the threads of the delivery screws move toward the free end of thecore assembly20. At the same time, the threads are continuously brought into contact with the inner peripheral surface of thepolygonal paper tube200, and cause the paper tube to move toward the free end of thecore assembly20.
• FIG. 22 is an exemplary view showing a state where a polygonal paper tube is manufactured using one-sided corrugated cardboard strips, which have corrugations parallel with the longitudinal direction of the strips. Referring toFIGS. 2 and 22, when using the method and apparatus according to an embodiment of the present invention, it is possible to manufacture a polygonal paper tube by arranging liner base papers a, e and f and one-sided corrugated cardboard b, c and d on thecore assembly20 in order shown in the figure. In the apparatus according to an embodiment of the present invention, the portion of a delivery member exposed to the outside in the core assembly moves toward the free end of the core assembly, so that it is possible to manufacture a paper tube without damaging the corrugations of the corrugated cardboard strips. Although one-sided corrugated cardboard strips are used in the present embodiment, it is not limited thereto and both-sided corrugated cardboard strips may be used. It is also possible to manufacture a paper tube with the direction of corrugated medium paper of one-sided corrugated cardboard reversed (that is, to face an inside surface of a polygonal paper tube to be formed). According to embodiments of the present invention, it is possible to manufacture a thick paper tube by discharging a plurality of paper strips helically overlapped and wound on a rotating core from the core using a delivery member which moves in the core. Also, according to embodiments of the present invention, since a thick polygonal paper tube can be manufactured, it is possible to provide a polygonal paper tube with high strength. In addition, according to embodiments of the present invention, even though a polygonal paper tube is manufactured using one-sided corrugated cardboard strips, it is possible to prevent corrugations of the corrugated cardboard from being damaged.
• According to embodiments of the present invention, since a paper tube is continuously produced by helically overlapping and winding strips, the productivity of the paper tube is superior. If there is provided a polygonal paper tube, which has high strength since the paper tube is thick, it is possible to provide a paper pallet with high strength and low costs. If a paper pallet with high strength is provided, it is possible to substitute paper pallets for wood pallets used in delivery of a weight, which can reduce felling and also contributing to the environment preservation.
• Embodiments of the present invention described above and shown in the figures should not be analyzed to limit the technical spirit of the present invention. The true scope of the present invention is defined only by the claims. Those skilled in the art of the present invention can modify and change the technical spirit of the present invention into various forms. Therefore, as far as the modifications and changes are apparent to those skilled in the art, the modifications and changes will belong to the true scope of the present invention.

Claims (24)

1. A tube comprising a hollow polygonal cross-sectional body of a plurality of layers, which comprises at least one corrugated paper layer, wherein at least one of the plurality of layers comprises at least one continuous paper band that is spirally arranged so as to define a polygonal cross-section.

2. The tube ofclaim 1, wherein the at least one corrugated paper layer comprises at least one continuous corrugated paper band that is spirally arranged so as to define a polygonal cross-section.

3. The tube ofclaim 2, wherein each continuous corrugated paper band comprises a non-corrugated paper band and a corrugated paper structure bonded onto the non-corrugated paper band.

4. The tube ofclaim 2, wherein each corrugated paper layer extends free of a substantial gap between two neighboring portions of the continuous corrugated paper band.

5. The tube ofclaim 1, wherein the plurality of layers comprises an inner-most layer, an outer-most layer, and at least one intermediate layer, wherein the at least one intermediate layer comprises the at least one corrugated paper layer.

6. The tube ofclaim 5, wherein the at least one of the inner-most layer and the outer-most layer does not comprise a corrugated paper band.

7. The tube ofclaim 1, wherein each layer comprises a paper material.

8. The tube ofclaim 1, wherein the plurality of layers comprises a non-corrugated paper layer comprising a non-corrugated continuous paper band that is spirally arranged so as to define a polygonal cross-section, wherein a portion of the continuous, non-corrugated paper band is overlapping with another portion of the continuous, non-corrugated paper band in the spiral arrangement, wherein the overlapping portions are glued together.

9. The tube ofclaim 8, wherein each corrugated paper layer comprises a continuous corrugated paper band that is spirally arranged so as to define a polygonal cross-section, wherein the continuous corrugated paper band does not comprise portions that are overlapping with each other in the spiral arrangement.

10. An article comprising a tubular body extending in a longitudinal direction, wherein the tubular body has a polygonal cross-section in a plane generally perpendicular to the longitudinal direction, wherein the tubular body comprises a first layer and a second layer, wherein the second layer comprises a continuous paper band that is spirally arranged around the first layer, wherein at least one of the first and second layers comprises corrugated paper.

11. The article ofclaim 10, further comprises a plurality of additional tubular body arranged together so as to form a pallet.

12. The article ofclaim 10, wherein the first layer is the inner-most layer of the tubular body and comprises a continuous paper band that is spirally arranged so as to define a polygonal cross-section.

13. The article ofclaim 12, wherein the first layer does not comprise the corrugated paper.

14. The article ofclaim 10, wherein the second layer comprises a continuous corrugated band that is spirally arranged so as to define a polygonal cross-section around the first layer, wherein the continuous corrugated band comprises a continuous, non-corrugated band and the corrugated paper, which is bonded onto the continuous, non-corrugated band.

15. The article ofclaim 14, wherein the second layer extends substantially free of a gap between two neighboring portions of the continuous corrugated band.

16. The article ofclaim 10, wherein the tubular body further comprises a third layer interposed between the first and second layers, wherein the third layer comprises the corrugated paper.

17. A method of making a hollow tube, the method comprising:

spirally winding a plurality of bands around at least one rotating shaft so as to form a tubular body comprising a plurality of layers around the at least one shaft, wherein the tubular body comprises an inner surface;

frictionally engaging the inner surface with a friction surface movable in the tubular body; and

moving the friction surface so as to transfer the tubular body in a longitudinal direction thereof.

18. The method ofclaim 17, wherein frictionally engaging and moving occurs substantially simultaneously.

19. The method ofclaim 17, wherein frictionally engaging and moving occurs substantially continuously.

20. The method ofclaim 17, wherein the friction surface is part of a conveyor belt, a roller or a lead screw driven by a dedicated power source therefor.

21. The method ofclaim 17, wherein the at least one shaft comprises a plurality of edges extending in the longitudinal direction, wherein the plurality of bands are winding around the plurality of edges such that the tubular body has a polygonal cross-section.

22. The method ofclaim 21, further comprising cutting the tubular body transferred away from the friction surface, wherein prior to cutting, the method does not comprise substantially changing the polygonal cross-sectional shape of the tubular body.

23. The method ofclaim 17, wherein the tubular body is continuously moving generally in the longitudinal direction such that the plurality of bands are wound around a substantially identical portion of the at least one shaft.

24. The method ofclaim 17, wherein the plurality of bands comprises at least one corrugated paper band so as to form at least one corrugated paper layer.

Images