GB2185959A

GB2185959A - Core tube and procedure for manufacturing same

Info

Publication number: GB2185959A
Application number: GB08622416A
Authority: GB
Inventors: Ola Marttila; Magnus Johanson
Original assignee: SPIROLIT Oy AB
Current assignee: SPIROLIT Oy AB
Priority date: 1986-01-29
Filing date: 1986-09-17
Publication date: 1987-08-05
Also published as: FI860416A0; NO863685L; DE3633038A1; FI860416A; GB8622416D0; NO863685D0; DK444886A; SE8603922D0; DK444886D0; SE8603922L

Abstract

A core tube (1) for use as a reeling core of a paper roll, on which is formed at least one weakened line (2), by perforation, and extending substantially from end to end of said core tube. A method of making the core tube is also disclosed, in which the weakened line is formed by pressing a disc-like rotating perforation blade (11, Figure 3) through the core tube against a counter roller placed within the tube. <IMAGE>

Description

SPECIFICATION Core tube and procedure for manufacturing same The present invention relatestoacoretubeforuse as reeling core in a paper roll, and to a method for making the core tube.

The invention concerns in particular, though not exclusively, a so-called tear-out core tube, and its manufacturing, such tear-out core tube being meant to be removed bytearing a paperstripoutfrom within the roll e.g. when it is intended to pull a paper web to be used as a towel from the inside of the roll, as an example the paper rolls used as papertowel dispensers at service stations.

Tear-c ut core tubes are nowadays produced by gluing a helically disposed paper strip to become a tube, using tathis purpose a thinner and easierto tear paper strip which hereby joins the first margin of a sturdier paper strip, forming the helix, to the second margin of the next turn of the helix. It is then possible to tear the core tube apart by a pull exerted on the end of the helix, this causing the thinner paper strip to rupture and the core tube, which has been made of more durable paper strip,to come out in the shape of a helically wound strip.

The manufacturing of such a core tube consisting of two paper strips, one fairly strong and the other less strong, is however cumbersome asto its technology. Two different types of paper strip are needed to make the tube and in connection with manufacturing they have to be fed into a machine and glued to each other with exactly correct mutual positioning.

The object of the present invention is to provide a new type oftear-outcoretubefor use as reeling core which is free of the drawbacks mentioned and which can be manufactured more simply and with greater ease than the tear-out core tube of prior art.

It is a further object of the invention to teach a procedure for manufacturing a tear-out core tube by which the core tube can be manufactured more simply and in a way involving easiertechnologythan in the case of tear-out core tubes of prior art.

Regarding the features which characterize the product, respectively the procedure, ofthe invention, reference is made to Claim 1,respectively to Claim 4.

The invention is based on establishing a weakened line on the core tube by perforation in such manner that the core tube can be torn along said weakened line and be removed from the inside through the core tube aperture.

The weakened line advantageously forms a helix, conforminge.g.tothehelixofthepaperstripfrom which the core tube has been made. The weakened line may equally have a configuration other than that of said helix, e.g. that of a straight line. Furthermore, the core tube may present a plurality ofweakened lines.

The weakened line is advantageously produced with the aid of a disk-like, rotating perforation blade, this blade being pressed through the glued tube against a counter-roll placed inside the tu be and by moving the tube and the blade relative to each other in the longitudinal direction of the core tube. The perforation blade and core tube are preferably moved in relation to each other so that the blade is positioned atan oblique angle against the axis of the tube, appropriately an angle consistent with the pitch of the core tube, while tube and blade rotate with equal peripheral velocities.The weakened line may also be produced on the core tube by preperforating the strip of which the coretube is made, in which case the completed core tubewill inherently carry a helical line conforming to the run of the paper strip.

The invention is described in detail in the following with the aid of embodiment examples, referring to the attached drawings, wherein: Figure 7 presents an elevational view of a core tube, intended to be used as reeling core in a paper roll, according to the invention; Figure2 illustrates, in a schematic diagram,the perforation by the procedure of the invention; and, Figure 3 presents the blade used to carry outthe perforation in the procedure of Figure 2.

In Figure 1 can be seen a core tube 1, intended for use as a reeling core in a paper roll, which has been manufactured of a paper strip 3 by winding this strip material helicallytoform a coretube and bygluing the margins of the strip upon each other. If desired, the core tube may equally be made of a pluralityof paper strips glued on each other. As taught bythe invention, on the core tube has been formed a weakened line 2 extending substantially from one end to the other ofthe tube and along which the core tube can with ease be torn and subsequently removed through the core tube aperture, that is, through the hollow space defined by the core tube.

Removal of the core tube becomes necessary when upon the core tube has been reeled up e.g. paper intended to be used as a discardabletowelwhich has to be extractable from within, i.e. through the core tube aperture, after the core tube has first been removed from within the roll.

In Figure 1 is furthermore seen the gluejoint7 of the paper strip (the solid helical line), which constitutes on the surface of the core tube a helix conforming to the helix of the strip 3. Furthermore, in the embodiment depicted in Figure 1 theweakened line 2 forms on the paper strip 3 and on the glue joint 7 thereof a helix conforming to said helix.

In Figure 2 is schematically illustrated the mode of forming the weakened line on the surface of the core tube which has been manufactured bya procedure known in itself in the art, by composing it of a paper strip by gluing; gluing the strip and forming it are procedures previously known in themselves and are therefore not described in greater detail here. The core tube has been manufactured in the shape of an elongated blank 8, from which separate core tubes 11, 12,3,14and 15 are meantto be separated by cross-cutting the blank at the cutting points 9. The coretube blank has further been placed upon a roll 5 which is rotatably carried (10) and provided with a power means (not depicted) for rotating the roll.A substantially round, disk-like perforation blade 11, carried to be freely rotatable on its axle 12 that the blade is positioned at an oblique angle (in the embodiment here depicted, an angle consistent with the helix of the tube) to the axis 6 of the core tube.

Perforation is accomplished by moving the core tube 1,i.e.,thecoretube blank8, and the perforation blade 4 in relation to each other in the direction ofthe core tube's axis while atthe same time coretube and perforation blade rotate in relation to each other in opposite directions with substantially equal peripheral velocities in such manner that the perforation blade partly penetrates through the core tube. In the embodiment depicted, the roll 5 has been provided with a drive means, i.e., a rotating machinery (not depicted), and the perforation blade is freely rotatable. Moreover, the perforation blade is freely movable, e.g. along a slide rod, in the direction longitudinal to the roll Sand to the coretube blank8.

If desired, the perforation blade too may be provided with a drive mechanism, in which case the roll 5 may be freely rotatable or likewise provided with drive machinery.

Figure 3 shows the perforation blade 11 in elevational view. The blade is a round disk-like plate of which the outer periphery has been provided with points 13 placed with a given spacing and meantto be pressed through the core tube in connection with the perforation process, as is commonly known in association with any perforation process. In the figure, the points have been shown partially only in order to simplify the construction.

The embodiment examples are merely meant to illustrate the invention, and embodiments of the invention may vary within the scope of the claims following below.

Claims

1. A core tube for use as a reeling core of a paper roll, in which the core tube has at least one weakened line formed by perforation and extending substantially from end to end of said core tube, so thatthecoretubecan betornalongtheweakened line and removed through the core tube aperture.

2. Acoretube according to Claim 1, in which the weakened line forms a helix.

3. A core tu be according to Claim 2, in which the core tube is made of a paper strip by winding and gluing, and the helix of the weakened line conforms to the helix of the paper strip.

4. A method of making a core tube for use as a reeling core of a paper roll, said core tube being made of a paper strip by gluing, in which aweakened line is formed on the core tube by perforation and substantially from one end to the other of the core tube.

5. A method according to Claim 4, in which the weakened line is formed by pressing a disk-like rotating perforation blade through the glued core tube against a counter-roll placed within the core tube, and by moving the core tube and the blade relative to each other longitudinally of the core tube.

6. A method according to Claim 5, in which the core tube and the perforation blade are moved in relation to each other while atthe same time the core tube is rotated and in such mannerthatthe blade is positioned atan oblique angle (cm), preferablyatan angle consistent with the helix of the core tube, to the axis of the core tube.

7. A method according to Claim 4, in which a weakened line is formed on the core tube by making the core tube of a glued paper strip on which has been formed a weakened line longitudinal to the strip.

8. A core tube according to Claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.

9. A method according to Claim 4 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.