EP4588651A1

EP4588651A1 - Method and apparatus for manufacturing spiral paper tubes composed of at least two strands of material

Info

Publication number: EP4588651A1
Application number: EP24152671.4A
Authority: EP
Inventors: Maciej WITKOWSKI
Original assignee: International Tobacco Machinery Poland Sp zoo
Current assignee: International Tobacco Machinery Poland Sp zoo
Priority date: 2024-01-18
Filing date: 2024-01-18
Publication date: 2025-07-23
Also published as: WO2025153724A1

Abstract

An apparatus (1) for manufacturing spiral tubes (2) composed of at least two strands of material (10, 10'), provided with a unit (4, 4') feeding the strands of material (10, 10'), a forming mandrel (13) for forming a continuous spiral tube (3), a forming unit (6) provided with a forming belt (14) running at an angle (α) relative to the longitudinal axis (X) of the forming mandrel (13), characterised by being further provided with a vision system (18) generating a digital image of the formed continuous spiral tube (3) moving on the forming mandrel (13) below the forming unit (6), and a controller unit (19) extracting from the image a set of first physical parameters concerning the base position (8) of the joint (21) between the edges (C, D) of the strand of material (10) forming the continuous spiral tube (3) and the distance (d₁, d₂) of the edges (C, D) of the strand of material (10) from the base position (8), and the forming unit (6) is adapted to adjust the angle (α) at which the forming belt (14) runs relative to the longitudinal axis (X) of the forming mandrel (13) so that the distance (d₁, d₂) between the edges (C, D) of the strand of material (10) and the base position (8) of the joint (21) approaches zero. The object of the application is also a method of adjustment.

Description

The object of the invention is a method and apparatus for manufacturing spiral paper tubes composed of at least two strands of material.
Spiral tubes manufactured by rolling strands of material which, when rolled up, form layers of tubing, are used in many branches of food industries. Spiral tubes can be multi-layered, whereas at least two layers of material are required to manufacture a tube of stable shape. Spiral tube forming apparatuses are known, among others, from the documents DE1786551A1 , EP1631425B1 , US3150575A , US4378966A , US3942418(A ), WO2020099360A1 , WO2020099361A1 . Apparatuses for forming a spiral tube in both vertical and horizontal arrangement are known, whereas individual tubes are cut off by means of usually circular knives, slidable in the direction of movement of the tube to be formed.
In known apparatuses, spiral tubes are manufactured in winding apparatuses for spiral winding of paper strips around a mandrel to form a base tube. During winding, at least one of the strips is placed with the contact side in direct contact with the mandrel. In addition, the tube making systems comprise apparatuses feeding the strips to the winding apparatus, cutting apparatuses to cut the made tube to a predetermined length to form the tube sections. The system may comprise a lubricating apparatus along which at least one selected strip is moved so as to apply a layer of lubricating material on the contact side of at least one strip before at least one strip is wound around the mandrel. The lubricating apparatus may comprise at least one lubricating element, having a cylindrical outer surface and made of a lubricating material.
Also known from publications WO2020099360A1 , WO2020099361A1 is the use of a forming belt which winds around the mandrel and presses the paper strips against each other and around the mandrel to form a spiral tube.
In known tube making apparatuses, one of the rollers around which the forming belt is guided is stationary and the other is adjustable and is used to tension the forming belt, so the rollers are not symmetrically arranged with respect to the continuous tube forming place around which the forming loop of the forming belt is wound. The distance of one roll to the forming loop and the forming mandrel is fixed, while the distance of the other roll to the forming loop and the forming belt can vary, which can lead to deformation of the forming mandrel and variations in production parameters, thus to the manufacture of tubes of reduced quality.
The object of the invention is an apparatus for manufacturing paper spiral tubes composed of at least two strands of material, provided with a feeding unit for feeding the strands of material, a forming mandrel for forming a continuous tube, a forming unit provided with a forming belt running at an angle to the longitudinal axis of the forming mandrel. The apparatus according to the invention is characterised by being provided with a vision system generating a digital image of the formed continuous spiral tube moving on the forming mandrel below the forming unit, a controller unit extracting from the image a set of first physical parameters concerning the base position of a joint between the edges of the strands of material forming the continuous spiral tube and the distance of the edges of the strands of material from the base position, and the forming unit is adapted to adjust the angle at which the forming belt runs relative to the longitudinal axis of the forming mandrel so that the distance between the edges of the strands of material and the base position of the joint approaches zero.
Preferably, the apparatus according to the invention is characterised in that the set of first physical parameters concerning the base position of the joint is initially extracted from the reference image of the calibration instrument.
Preferably, the apparatus according to the invention is characterised in that the controller unit is provided with a PID controller which receives a signal of distance between the edges of the strands of material and generates a signal for adjusting the angle at which the forming belt runs relative to the longitudinal axis of the forming mandrel.
The object of the invention is also a method for manufacturing spiral paper tubes composed of at least two strands of material, wherein the strands of material are fed by winding them around the forming mandrel to the forming unit, a continuous spiral tube is formed in the forming unit, the spiral tube being formed by means of the forming belt running at an angle to the longitudinal axis of the forming mandrel. The method according to the invention is characterised in that a digital image of the formed tube moving on the forming mandrel below the forming unit is generated, a set of first physical parameters concerning the base position of the joint between the edges of the strands of material forming the continuous spiral tube and the distances of the edges of the strands of material from the base position are extracted from the image, and the angle at which the forming belt runs relative to the longitudinal axis of the forming mandrel is adjusted so that the distance between the edges of the strands of material and the base position of the joint approaches zero.
Preferably, the method according to the invention is characterised in that the set of first physical parameters concerning the base position of the joint is initially extracted from the reference image of the calibration instrument.
Preferably, the method according to the invention is characterised in that the adjustment of the angle at which the forming belt runs relative to the longitudinal axis of the forming mandrel is performed by generating a signal by the PID controller receiving the distance signal between the edges of the strand of material.
An advantage of the apparatus and method according to the invention is obtaining spiral paper tubes with significantly improved quality parameters and increasing the stability of the spiral paper tube production process.
The object of the invention is illustrated in more detail in a preferred embodiment in a drawing in which:

Fig. 1: shows, in simplified terms, an apparatus for making spiral tubes;
Fig. 2: first view of a measuring area observed by the vision system of the apparatus according to the invention;
Fig. 3: second view of the measuring area observed by the vision system of the apparatus according to the invention;
Fig. 4: third view of the measuring area observed by the vision system of the apparatus according to the invention;

Fig. 1 shows, in simplified terms, an apparatus for making spiral tubes according to the invention. The apparatus 1 for manufacturing spiral tubes 2, substantially of paper, cut from a continuous spiral tube 3 comprises feeding units 4, 4' for feeding strands of material 10, 10', further comprises an adhesive unit 5, a forming unit 6, a cutting head 7. Strands of material 10, 10' of paper are usually used to manufacture the spiral tubes 2, but it is possible to use the apparatus 1 for manufacturing the spiral tubes 2 made of another material in the form of a strand, for example a biodegradable film of plant origin.
The feeding unit 4, 4' for feeding the strand of material 10, 10' is adapted to unwind the strand of material from a bobbin and feed this strand to the forming unit 6. In the embodiment shown in Fig. 1 , the apparatus 1 is provided with two feeding units 4, 4' for feeding two strands of material 10, 10'. For the sake of simplicity, the bobbins from which the material strands 10, 10' are unwound are not shown in the figure. The strand of material 10, 10' is fed through a plurality of rollers, in the figure the last roller for each strand of material 10, 10' is marked as 11, 12, from these rollers the material strand 10, 10' runs directly to a forming mandrel 13 in the forming unit 6. The strand of material 10' runs by the adhesive unit 5 which feeds the glue continuously onto the surface of such strand.
The forming unit 6 is adapted to receive the strands of material 10, 10' and to wind these strands around the forming mandrel 13 in such a way that they form a layer of continuous spiral tube from the strand of material, hereinafter the formed tube will be referred to as continuous tube or continuous spiral tube 3. The strand of material 10' is wound around the forming mandrel 13 first to form the first layer of the continuous spiral tube 3, and then the strand of material 10 is overlap-wound onto the wound strand 10' to form the outer layer of the continuous spiral tube 3. The strand of material 10 and 10' is wound on the forming mandrel 13 at an angle β relative to the longitudinal axis X. The angle β should have substantially the same value for both strands of material 10 and 10'. Both strands of material 10 and 10' have substantially the same width so that by overlapping them at the same angle β of winding on the forming mandrel 13, a covering of a joint 21' formed on the strand of material 10' by the outer strand of material 10 will be obtained, as shown in Fig.4 The forming unit 6 comprises a drive unit 15 provided with a symmetrical movement mechanism (not shown in the figure), the forming mandrel 13 and a forming belt 14 wound around the rollers 16, 17. Each of the rollers 16, 17 can be a drive roller, and it is also possible to drive both rollers 16, 17 simultaneously, for example by means of two motors synchronised with each other, whereas the motors can be synchronised such that alteration in speed for each motor is carried out in the same way. In this embodiment, the roller 16 is a drive roller driven by a motor M and the roller 17 is a passive roller.
The cutting head 7 is situated below the forming mandrel 13 and is arranged to cut individual spiral tubes 2 from the continuous spiral tube 3. The cutting head 7 is provided with a body in which circular knives are fixed, the channel for the continuous spiral tube 3 being situated coaxially with the forming mandrel 13. The circular knives rotate about their axes and, when cutting the tube, move in a direction parallel to the axis of rotation of the body 7 at a speed equal to the forming speed of the continuous spiral tube 3, which makes it possible to cut individual spiral tubes 2 from the moving continuous spiral tube 3. The operation of such a cutting head is described in more detail in the international publication WO2020099361A1 . From the cutting head 7, the individual spiral tubes 2 can be received in any way, for example onto a belt conveyor or onto a drum conveyor.
The continuous spiral tube 3 is formed by the forming loop 14A of the forming belt 14 in the forming unit 6, whereas the forming loop 14A is centrally situated between the loops 14B and 14C of the forming belt 14 ( Fig. 1 ) wound around the rollers 16 and 17 of the drive unit 15, the rollers 16, 17 being fixed on a symmetrical movement mechanism (not shown). The symmetrical movement mechanism is arranged to move the rollers 16, 17 simultaneously away from each other or towards each other, i.e. synchronously in opposite directions, for example in order to alter the tension of the forming belt 14. An alteration in the position of the rollers 16, 17 may be necessary due to the selection of optimal operating parameters of the apparatus 1. During the insertion and replacement of the forming belt 14, the forming loop 14A does not change its position, so there is no force directed transversely to the forming mandrel 13 that can deform such mandrel. Forming the continuous spiral tube 3 requires tension to some extent in the forming belt 14. The symmetrical movement of the rollers 16, 17 ensures that in the loops 14B, 14C of the forming belt 14, when the manufacturing speed varies, the tension varies in a similar manner over the entire speed range of the manufacturing apparatus 1 of the spiral tubes 2 so that the oppositely directed forces acting on the forming mandrel 13 have similar values and the forming mandrel 13 is not deformed during the operation of the apparatus. The symmetrical movement mechanism can be adapted to move the drive roller 16 together with the drive unit and the roller 17, which is a passive roller, at the same time away from each other or towards each other.
The apparatus 1 for manufacturing the paper spiral tubes 2 composed of at least two strands of material 10, 10', is further provided with a vision system 18 generating a digital image in the observation area 9 of the formed continuous spiral tube 3 moving on the forming mandrel 13 below the forming unit 6. The apparatus 1 according to the invention is provided with a controller unit 19 extracting from the image of the continuous spiral tube 3 a set of first physical parameters concerning the base position B of the joint 21 between the edges C, D of the strand of material 10 forming the outer layer of the continuous spiral tube 3 and the distances d1, d2 of the edges C, D of the strand of material 10 from the base position B.
The measurement of distance and extraction of features from a video image involves, for example, the use of known edge-identifying image processing algorithms, and algorithms that calculate the distance in SI units or in synthetic units, the distance can, for example, be represented by the number of pixels between two material strand edges identified in the image.
The first physical parameters concerning the base position B of the joint 21 between the edges C, D of the strand of material 10, are parameters determined, for example, by the measurement of the calibration instrument which is placed in the observation area 9 of the vision system 18. Alternatively, the base position B may be calculated from the parameters of the shape of the tube 3 taking into account its diameter, the feeding speed and the designed angle β at which the strands of material 10, 10' are wound around the forming mandrel 13 and the width of the strand of material 10, 10'.
Furthermore, in the embodiment shown, the apparatus 1 has an illuminator 8 adapted to illuminate the controlled surface of the continuous spiral tube 3 in the observation area 9. The illuminator 8 is in the form of a ring mounted coaxially on the continuous spiral tube 3. Since it is ring-shaped, this allows the manufactured continuous spiral tube 3 to be accurately illuminated from all sides simultaneously. Preferably, the light rays 20 extend from the illuminator 360° around the longitudinal axis X of the forming mandrel 13. Furthermore, the small angle of incidence of the light rays 20 from the illuminator 8 on the surface of the continuous spiral tube 3 highlights any imperfections present on its surface, by more easily generating shadows arising from these defects. It is essential that the angle of incidence of the light rays 20 from the illuminator 8 on the surface of the tube being manufactured is between 1- 45°, preferably 5-30°.
The observation area 9 shown in Figs. 2 and 3 may preferably comprise a section of the continuous spiral tube 3, in which several coils of the material strands 10 are visible, and several sections of the joint 21, between the edges C, D of the material strand 10. In such case, it is possible to average the measurements or to increase the frequency of calculation of the distance d₁, d₂ of the edges C, D of the material strand 10 from the base position B.
Fig. 2 shows a situation where the edges C, D of the continuous strand of material 10 diverge and a gap 22 is formed between them, the reason for such a phenomenon may be a variation in the physical parameters of the strand of material 10, a variation in environmental parameters, e.g. a variation in humidity or temperature, or winding of the strand of material 10 on the forming mandrel 13 at an angle β being too small. The vision system 18 captures an image in the observation area 9, determines from the image the distances d₁, d₂ between the edges C, D of the strand of material 10 and the line representing the base position B shown in the figure by the dashed line. The first distance d₁ is measured from the first edge C of the strand of material 10 to the base position B. The second distance d₂ is measured from the second edge D of the strand of material 10 to the base position B. Between the edges C and D, at the slot 22, the strand of material 10' constituting the inner layer of the continuous spiral tube 3 is visible.
Fig. 3 shows a situation in which the strand of material 10 overlaps, i.e. a situation in which the strand of material 10 has been wound onto the forming mandrel 13 at an angle β being too large so that in the recorded image only a single edge C of the strand of material 10 and only one distance d₁ defined in relation to the line representing the base position B of the joint 21 are visible. Since the second edge D is under the strand of material 10, it is not visible and has been marked with a dotted line.
Fig. 4 shows a magnified image from the observation area 9 in which the outer layer of the continuous spiral tube 3 formed by the strand of material 10 with a properly made joint 21 is visible. The visible strand of material 10 has a width W and is wound on the forming mandrel 13 (not shown) at an angle β relative to the longitudinal axis X. The edges C and D of the strand of material 10 are also situated at the base position B. Both edges C and D descend to the face and coincide with the base position B. The distances d₁, d₂ in this case are equal to zero.
Furthermore, the forming unit 6, in response to the signal representing the measured distance d₁, d₂ of the edges C, D of the strand of material 10 from the base position B is adapted to adjust the angle at which the forming belt 14 runs relative to the longitudinal axis X of the forming mandrel 13 so that the distance d₁, d₂ between the edges C, D of the material strands 10 and the base position B of the joint 21 approaches zero. The forming unit 6 or the controller unit 19 of the apparatus 1 is provided with a PID controller which receives the signal of distance d₁, d₂ between the edges C, D, of the material strands 10 and generates a signal for adjusting the angle α at which the forming belt 14 runs relative to the longitudinal axis X of the forming mandrel 13. The settings of the PID controller determine the dynamics of the adjustment process.
According to the invention, a method for manufacturing spiral tubes 2 comprising at least two strands of material 10, 10' is introduced wherein the strands of material 10, 10' are fed by winding them around the forming mandrel 13 to the forming unit 6, the continuous spiral tube 3 is formed in the forming unit 6, the tube 3 being formed by means of the forming belt 14 running at an angle α relative to the longitudinal axis X of the forming mandrel 13. In the method according to the invention, a digital image of the formed spiral tube 3 moving on the forming mandrel 13 below the forming unit 6 is generated. A set of first physical parameters concerning the base position B of the joint 21 between the edges C, D of the strand of material 10 forming the continuous spiral tube 3 and the distance of the edges C, D of the material strand 10 from the base position B is then extracted from the image, and the angle α at which the forming belt 14 runs relative to the longitudinal axis X of the forming mandrel 13 is adjusted so that the distance d₁, d₂ between the edges C, D of the strand of material 10 and the base position B of the joint 21 approaches zero.
The set of first physical parameters concerning the base position B of the joint 21, is initially extracted from the reference image of the calibration instrument. In the method according to the invention, the adjustment of the angle α at which the forming belt 14 runs relative to the longitudinal axis X of the forming mandrel 13 is performed by generating a signal by the PID controller receiving the signal of distance d₁, d₂ between the edges C, D of the strands of material 10 and the base position B of the joint 21.

List of elements

1	Apparatus	M	drive
2	Spiral tube	B	base position
3	Continuous spiral tube	d₁	distance of the edge C of the strand of material from the base position
4	Material strand feeding unit	d₁
4'.	Material strand feeding unit	d₂	distance of the edge D of the strand of material from the base position
5	Adhesive unit	d₂
6	Forming unit	X	longitudinal axis of the forming mandrel
7	Cutting head	C	edge of a strand of material
8	Illuminator	D	edge of a strand of material
9	Observation area	α	winding angle of the forming belt relative to the longitudinal axis of the forming mandrel
10	Strand of material
10'	Strand of material
11	Guide roller	β	angle of winding the material strands on the forming mandrel
12	Guide roller	β
13	Forming mandrel
14	Forming belt
14a	Forming loop
14b	Loop
14c	Loop
15	Drive unit
16	Roller
17	Roller
18	Vision system
19	Controller unit
20	Beams of light
21	Joint
22	Gap

Claims

An apparatus (1) for manufacturing spiral tubes (2) composed of at least two strands of material (10, 10'), provided with
a feeding unit (4, 4') for feeding the strands of material (10, 10');

a forming mandrel (13) for forming a continuous spiral tube (3);

a forming unit (6) provided with a forming belt (14) running at an angle (α) to the longitudinal axis (X) of the forming mandrel (13);

characterised by being further provided with a vision system (18) generating a digital image of the formed continuous spiral tube (3) moving on the forming mandrel (13) below the forming unit (6), and

a controller unit (19) extracting from the image a set of first physical parameters concerning the base position (B) of a joint (21) between the edges (C, D) of the strand of material (10) forming the continuous spiral tube (3) and the distances (d₁, d₂) of the edges (C, D) of the strand of material (10) from the base position (B), and

the forming unit (6) is adapted to adjust the angle (α) at which the forming belt (14) runs relative to the longitudinal axis (X) of the forming mandrel (13) so that the distance (d₁, d₂) between the edges (C, D) of the strand of material (10) and the base position (B) of the joint (21) approaches zero.
The apparatus as in claim 1, characterised in that the set of first physical parameters concerning the base position (B) of the joint (21) is extracted from the reference image of the calibration instrument.
The apparatus as in claim 1 or 2, characterised in that the controller unit (19) is provided with a PID controller which receives a signal of distance (d₁, d₂) between the edges (C, D) of the strand of material (10) and generates a signal for adjusting the angle (α) at which the forming belt (14) runs relative to the longitudinal axis (X) of the forming mandrel (13).
A method for manufacturing paper tubes (2) composed of at least two strands of material (10, 10'), wherein
the strands of material (10, 10') are fed by winding them around the forming mandrel (13) to the forming unit (6), a continuous spiral tube (3) is formed in the forming unit (6), the continuous spiral tube (3) being formed by means of the forming belt (14) running at an angle (α) to the longitudinal axis (X) of the forming mandrel (13);
characterised in that further a digital image of the formed continuous spiral tube (3) moving on the forming mandrel (13) below the forming unit (6) is generated,

a set of first physical parameters concerning the base position (B) of the joint (21) between the edges (C, D) of the strands of material (10) forming the continuous spiral tube (3) and the distances (d₁, d₂) of the edges (C, D) of the strand of material (10) from the base position (B) is extracted from the image, and

the angle (α) at which the forming belt (14) runs relative to the longitudinal axis (X) of the forming mandrel (13) is adjusted so that the distance (d₁, d₂) between the edges (C, D) of the strands of material (10) and the base position (B) of the joint (21) approaches zero.
The method as in claim 4, characterised in that the set of first physical parameters concerning the base position (B) of the joint (21) is initially extracted from the reference image of the calibration instrument.
The method according to claims 4 or 5, characterised in that the adjustment of the angle (α) at which the forming belt (14) runs relative to the longitudinal axis (X) of the forming mandrel (13) is performed by generating a signal by the PID controller receiving the distance signal (d₁, d₂) between the edges (C, D) of the strand of material (10).