Method and a device for detecting the turned segments in a movable shaft in a multi-segment in the machine used in the tobacco industry

Description of the invention

The present invention relates to a method and a device for detecting rotated segments in a multi-segment roller moved in a machine used in the tobacco industry.

The tobacco industry produces cigarettes equipped with filters, and the filters may be made of a single type of material or may be composed of a number of materials with different physical properties. Filters with several segments with different filtration properties are increasingly used in cigarettes produced today. Machines are known in the art for producing multi-segment filter bars from endless multi-segment filter rolls. These machines assemble a plurality of different segments fed from a plurality of feeding devices, the segments formed by cutting filter rods moved, for example, on a drum conveyor using a cutting head equipped with circular knives. The individual segments are arranged side by side or one behind the other, depending on the device, to finally form an endless multi-segment roller cut into single multi-segment bars. In further stages of the cigarette production process, multi-segment bars are cut into single multi-segment filters applied to individual cigarettes.

A very important aspect of the production of multi-segment bars is their quality. The quality is determined by keeping the dimensions of the bar, for example, the diameter and length, but also by keeping the sequence of the segments and the spacing between the segments. Moreover, it is essential that the segments are correctly positioned with their axes in relation to the axis of the manufactured shaft or the direction of its production. Currently, cigarette manufacturers use shorter and shorter segments, for example those whose length (axial dimension) is similar to their diameter. Filters are also known in which the applied segments have a length less than a diameter, for example 5 mm or less. For such segment proportions there is a risk of the segment rotating such that its axis is non-parallel, for example perpendicular to the axis of the shaft in which it is placed. This is possible since the dimensions of the space provided for such a segment will allow it to be positioned, with some deformation of the segment, both with the axis parallel to the axis of the entire shaft as well as substantially perpendicular to the axis of the shaft. With a slightly larger segment deformation, it is also possible to position such a segment angularly with respect to the shaft axis. The direction of rotation with respect to the shaft and the angle of rotation are therefore completely random. Moreover, the rotated segment itself is deformed, as is the tissue itself that wraps the multi-segment roller, locally adopting an outline similar to that of the segment. In other words, by turning the segment, the shaft produced is deformed to some extent, i.e. in the region of an incorrectly positioned segment, the shaft is not cylindrically formed. As the manufacturers expect, multi-segment bars with flipped segments should be rejected from production.

Systems for the quality control of multi-segment rollers are known in the art. Such systems are described in US 4,001,579, US 4,212,541, GB 2043962 and US 2011 / 162665A1. They relate to checking the types of segments, to the relative positioning of successive segments in the shaft, and to adjusting the cut length of a multi-segment bar. However, they do not disclose how to detect rotated segments.

The object of the present invention is to provide a method and a device for the reliable and quick detection of rotated segments such that the detection takes place irrespective of the direction in which the segments are rotated.

According to the invention, a method of detecting rotated segments in a multi-segment roller moved in a machine used in the tobacco industry by producing a shape error signal of said roller, comprising a plurality of consecutive segments in a common casing, is provided, in which the roller moving linearly along its axis is scanned simultaneously using at least two optical sensors, whose scanning directions are at an angle other than 90 ° to each other.

The method according to the invention is characterized in that by repeatedly scanning at such a frequency that the shortest segment in the roller is scanned at least once, the diameter of the roller is measured, the results of the successive scans being compared with a defined reference result and any difference between any scan result and the reference result are converted to a shape error signal.

The roller can be scanned with two optical sensors with scanning directions directed mutually at an angle ranging from 40 ° to 60 °, preferably 45 °.

PL 223 633 B1

According to the invention, there is also provided a device for detecting rotated segments in a multi-segment roller moved in a machine used in the tobacco industry by generating a shape error signal of said roller comprising a plurality of consecutive segments in a common casing, comprising at least two optical sensors for scanning the moving roller, which the scanning directions are at an angle different from 90 ° to each other.

The device according to the invention is characterized in that the optical sensors are adapted to measure the diameter of the roller by repeatedly scanning it with a frequency such that the shortest segment on the roller is scanned at least once, the device being further provided with a controller enabling the results to be compared successively. scans with a specific reference result, which converts any detected difference between any scan result and the reference result into a shape error signal.

The device may contain two optical sensors with scanning directions directed mutually at an angle ranging from 40 ° to 60 °, preferably 45 °.

Preferably, each sensor comprises a radiation source, preferably in the visible range, and a photosensitive element, the radiation source and the photosensitive element being arranged mutually on two sides of the moving roller.

Preferably, the sensors are line sensors.

Preferably, the scanning planes of the line sensors substantially coincide.

Alternatively, the sensors are surface sensors.

Preferably, the scanning surfaces of the line sensors substantially coincide.

The advantage of the method and device according to the invention is efficient operation with a low-cost and simple method of implementing the solution according to the invention.

The subject of the invention is shown in more detail in a preferred embodiment in the drawing, in which: Fig. 1 shows an exemplary multi-segment filter roller; Fig. 2 illustrates another exemplary multi-segment filter roller; Fig. 3a shows a detail of a machine for producing multi-segment bars; Fig. 3b shows exemplary bars one of which has a shape error; Fig. 4 shows the shaft of Fig. 1 with the segment rotated; Fig. 5 shows the roller of Fig. 1 with a differently rotated segment; Fig. 6 shows a section through the plane AA of a rotated segment in the shaft of Fig. 5; Figure 7 is a section view on BB of a rotated segment in the shaft of Figure 5; Figure 8 shows an array of two optical sensors; Figures 9a and 9b show the operation of individual linear optical sensors for a non-rotated segment; Figures 10a and 10b show the operation of individual line sensors for a pivoted segment; fig. 11a and 11b show the operation of individual surface optical sensors for a non-rotated segment; Figures 12a and 12b show the operation of individual surface optical sensors for a rotated segment; Figure 13 shows the scan points on the roller of Figure 2; Fig. 14 shows the results of scanning the roller of Fig. 1 using line sensors.

Figures 1 and 2 show schematically portions of exemplary multi-segment filter rollers CR1, CR1 'comprising alternating segments 2 and 3 in Figure 1 and segments 2, 3 and 4 in Figure 2, typically cylindrical segments - full or tubular made of various filter materials. The segments may be arranged in a sequence directly one after the other or spaced and are enclosed in a common casing, in particular they are wrapped in tissue paper. In the figure, multi-segment rollers are shown as if the tissue paper was transparent. As can be seen in Fig. 3a, showing a fragment of a machine for producing multi-segment bars S from rollers CR1, CR1 ', the feeding unit 101 feeds the filter segments prepared in advance on the conveyor 102, with the tissue 103 being placed on its surface. of segments on the conveyor 102, the paper 103 is wrapped in known manner around the segments and sealed. The resultant multi-segment roller CR moves through the operating zone of the control unit 104 and is then cut into segments S by a cutting head 105 equipped with knives 106. The typical means for supporting and guiding the roller CR are omitted in the drawing.

Fig. 3b shows three exemplary bars S, S 'and S, the bar S' having a defect which will be detected by the device according to the invention, and as a result the bar S 'will be rejected from the production process.

PL 223 633 B1

The segment 2 is the shortest of the segments in both the examples shown in Figures 1 and 2, its length being similar to the diameter of the filter roll. In manufacturing a multi-segment filter roll, it may happen that such short segments may be accidentally rotated. In Figures 4 and 5, such rotated segments are designated 2A and 2B. The axial direction of the roller movement during manufacture is shown by arrow 10. The Y axis of the CR1 multisegment roller in Fig. 4 lies in the drawing plane, while the XA axis of the rotated segment 2A is perpendicular to the drawing plane. 5, the XB axis of the segment 2B is inclined to the drawing plane and perpendicular to the Z axis, and it is possible to set the XB axis at an angle to the Z axis. in Fig. 5. The reference numeral 11 refers to a tissue paper with which the roller segments CR1 are wrapped. The tissue paper 11, which is cylindrically shaped along the entire length of the shaft, is deformed in the region of the rotated segment so as to encircle the rotated segment. In other words, the tissue paper 11 passes from a cylindrical configuration to a shape similar to that of the rotated segment 2B and again to a cylindrical configuration. In Fig. 7, the tissue paper 11 has a circular section corresponding to the circular section of a segment 3 around which the tissue paper is cylindrically shaped.

In manufacturing the multisegment filter roller CR, the roller passes through the region of operation of at least two optical sensors 5 which together constitute a shape sensor 12 adapted to measure the diameter of the roller shown in Fig. 8, which may belong to the control unit 104 shown in Fig. 3a. The sensors 5 operate in the plane of the drawing, while the multi-segment roller moves in a direction perpendicular to the plane of the drawing. Each optical sensor 5 comprises a radiation source 6, for example in the visible range, and a photosensitive element 7, both sensors being connected to the controller 8. The radiation source 6 may be linear or surface, similarly the photosensitive element 7 may be linear or linear. surface. Marker 9 shows the scanning direction of the optical sensor 5. 8 shows a shape sensor 12 comprising two optical sensors 5 scanning in the scanning directions 13 and 14, the optical sensors being connected to a controller 8 for controlling the operation of the sensors 5. The scanning directions of the optical sensors are arranged angularly, the angle α being different from 90 °. Preferably, the angle between the scanning directions 13 and 14 is 45 °. For this angle, the detection efficiency of the rotated segments is greatest. This is due to the fact that the rotated segment of the multi-segment roller is a rectangle in cross-section and depending on the actual angle of rotation of the segment with respect to the directions of illumination of the roller, the sensors can give different signal values, most often it is an analog signal. The sensors 5 are arranged to measure the diameter of the shaft, and more specifically the diameters of its individual segments by multiple scans. The results of these measurements, i.e. the values ​​of the diameters of successive segments, are transmitted to the controller 8, which, in the event of a difference between a given result and a certain reference result initially introduced into the controller, generates a shape error signal. As a result, an error signal is generated whenever the diameter of a segment is different from the reference diameter. In the context of the present description, the shaft diameter is also understood to mean a dimension which may not actually be the diameter (if the segment is rotated and the shaft is therefore not cylindrical in this section), but is between the sections A1 and B1 or A2 and B2 (cf. Figures 9-a, 9-b). As shown by tests carried out for different angles between the sensor scanning directions, the greatest certainty of correct detection of rotated segments was achieved for the 45 ° angle. Importantly, the comparison of the obtained results and the generation of the corresponding shape error signals (in other words, diameter error) takes place in the controller 8, which is faster than, for example, comparing scanned images showing the deformation of the roller, as it requires much less information to be analyzed.

Fig. 9a shows an embodiment of the device according to the invention, in which the photosensitive element is made as a line element 7 '. In manufacturing the multisegment filter roll CR1, the linear radiation source 6 '(Fig. 9a) illuminates the roller CR1 and partially the photosensitive element 7' (Figs. 9a and 9b). In the case when there are no rotated segments in the multi-segment filter roller and there is no resulting shape error, two fragments (segments) A are illuminated₁ and b₁photosensitive element 7 'belonging to the line sensor 5'. Fig. 10a shows a line photosensitive element 7 'as in Fig. 9a, where, due to the rotation of the segment 2B, it is illuminated on two portions A₂ and b₂also shown in Fig. 10b in an axial direction view of the multisegment filter roller CR1. Depending on the alignment of the optical sensor 5 'with respect to the segment 2B, a situation is possible when A₂<A₁ and b₂<B₁. It is also possible that A₂= A₁

PL 223 633 B1 and B₂<Bi or B₂= Bi and A₂<Ai and the situation when A₂= Ai and B₂= Bi (ie the shaft deformation is "invisible" to the sensor), with the values ​​of A! and B-ι marked in Fig. 10a are taken as the reference results stored in the controller 8. In practice, certain limit values ​​A must be entered into the controller 8 to which the optical sensor is connected._g and b_g corresponding to a diameter greater than the nominal diameter of the shaft, that is, leave a tolerance field for the diameter of the shaft, which may vary to some extent during production. The controller will generate a shape error signal when one of the lit segments Ai, A₂, Bi, B₂ the photosensitive element 7 'will be smaller than A, respectively_g or B_g. In the shape sensor (Fig. 8), in which, for example, two linear optical sensors set at the right angle are used, in the case where for one sensor the situation is such that A₂= A₁ and b₂= B₁ and for the second sensor the situation is such that A₂<A₁and b₂<B₁a shape error signal from only one optical sensor will confirm that there is a rotated segment in the multi-segment filter roller. Regardless of the position of the rotated segment, the shape sensor will always detect an error in the shape of the shaft, i.e. it detects the rotated element.

Fig. 11a shows an embodiment of the device according to the invention, in which the photosensitive element is formed as a surface element 7 ", for example as a photosensitive matrix. In manufacturing the multisegment filter roller CR1, the flat radiation source 6 "illuminates the roller CR1 and partially the photosensitive element 7" (Figures 11a and 11b). In the case when there are no rotated segments in the multi-segment filter roller and the resulting error in the shape of the roller does not occur, two fragments of the element are illuminated - the P area₁ and r₁ photosensitive element 7 ''. Fig. 12a shows a surface photosensitive element 7 '' as in Fig. 11a, where due to the rotated segment 2B it is illuminated in two parts - P fields₂ and r₂, the field P₂<P₁and R.₂<R₁. Depending on the orientation of the 5 '' optical sensor relative to segment 2, a situation is possible when P₂<P₁ and r₂<R₁. It is also possible that P₂= P₁and R.₂<R₁ or R₂= R.₁and P₂<P₁ and the situation when P₂= P₁ and r₂= R.₁ (ie, shaft deformation is "invisible" to the sensor), where the P values₁ and r₁ shown in Fig. 11a are taken as reference results. In practice, certain reference results Pg and Rg corresponding to a diameter greater than the nominal diameter of the shaft must be entered into the controller to which the optical sensor is connected, i.e. there must be a tolerance field for the diameter of the shaft, which may vary to some extent during production. The controller will generate a shape error signal when one of the illuminated surfaces of the photosensitive element 7 "is smaller than P_g or R_g. In the shape sensor (Fig. 8), in which, for example, two surface optical sensors set at the right angle are used, in the case where the situation P occurs for one sensor₂= P₁ and r₂= R.₁ situation or P is the case for the second sensor₂<P₁ and r₂<R₁the shape error signal from only one optical sensor confirms that there is a rotated segment in the multi-segment filter roller. Regardless of the position of the rotated segment, the shape sensor will always detect an error in the shape of the shaft, i.e. it detects the rotated element. Any number of optical sensors can be used in the shape sensor. In this case, the error signal from each sensor can be used to confirm the detection of the rotated segment.

Fig. 13 shows an exemplary multisegment filter roller CR1 'in which vertical short lines M indicate the places for which scanning takes place as the roller is moved in the direction 10. Scanning with the shape sensor 12 is performed cyclically with an appropriate frequency such that the shortest element is scanned at least once along its length. The time between consecutive scans of the roller is selected to be less than a value equal to the length of the shortest segment divided by the speed of movement of the multi-segment filter roller. The shown exemplary spacing of successive scanning points on a moving roller serves only to illustrate how successive scanning points are distributed along the length of the roller. In fact, the number of such points will be greater and will result from the scanning frequency of for example 10 kHz, 20 kHz, 50 kHz or 100 kHz depending on the controller or computer used and the speed of the roller in the range for example 50 m / min to 600 m / min. The scanning frequency can be selected according to the speed of the roller. In Figure 13, the reference numeral "w" denotes the distances between successive points along the length of the roller at which the surface of the roller will be scanned. For example, for a scanning frequency of 20 kHz and a roller speed of 500 m / min, the surface of the roller will be scanned in the region of the shape sensor each time after a longitudinal movement of the roller by 0.416 mm, i.e. a 5 mm long segment will be scanned 12 times along its length. It is possible that the multi-segment roller is not

The PL 223 633 B1 is scanned along its entire length, and only on the sections with short segments. Figure 14 shows an exemplary scan result using the linear optical sensors with short vertical ML lines. The values ​​of A1 and B1 were recorded for the correctly positioned segments, while the values ​​of A2 and B2 were recorded for the rotated segment 2B. On the basis of the measured values ​​obtained, filter bars S 'within which the rotated segments are located can be rejected.