EP3085253B2 - Rod processing machine in the tobacco-processing industry, and method for producing multi-segment rods - Google Patents

Description

The present invention relates to a rod-making machine for the tobacco processing industry for producing multi-segment rods, comprising an endless, driven format belt for conveying a wrapping strip placed on the format belt and a series of segments placed on the wrapping strip, an enclosing device for enclosing the segments with the wrapping strip, and an optical measuring device for detecting a property of the multi-segment rod formed from the segments and the wrapping strip. The present invention further relates to a method for producing multi-segment rods in the tobacco processing industry.

A rod making machine in the tobacco processing industry for producing multi-segment rods with an endless format belt and an enclosing device has been known for a long time, see for example DE 27 36 871 A1 .

It is also already known to provide an optical measuring device in such a strand machine for detecting the individual segments, see for example EP 1 913 824 A1 The signal from such an optical measuring device is used, for example, to control the cutting position of a subsequent cutting device for cutting the endless strand into individual bars. Document EP 2 628 399 A1 discloses a rod-forming machine for multi-segment rods, comprising an endless, driven format belt for conveying a wrapping strip placed on the format belt and a series of segments placed on the wrapping strip, an enclosing device for enclosing the segments with the wrapping strip, and an optical measuring device for detecting a property of the multi-segment rod formed from the segments and the wrapping strip. Increasingly, opaque wrapping materials are being used in the tobacco processing industry, for which currently known optical measuring devices do not allow position detection of the segments in the closed rod. However, the use of non-optical measuring devices, such as microwave or X-ray measuring devices, is comparatively complex and expensive, and also requires considerable installation space. Furthermore, the latter are relatively slow in terms of the required evaluation speed, making them unsuitable for online measurement in online applications.

The object of the invention is to provide a strand machine and a method in which reliable optical detection of the segments is possible regardless of the nature of the wrapping material.

The invention solves this problem with the features of the independent claims. By arranging the light outlet upstream of the enclosing device in the conveying direction, an inspection of the segments before they are wrapped with the wrapping strip on the still open strand is possible. For a strand machine with a format belt, it is surprising that such an arrangement is possible, since very little space is available in the area upstream of the segment wrapping, and the field of view is usually obscured by a hold-down device for holding the segments down on the format.

Conventional optical sensors with corresponding optical elements can only partially reach all inspection points. Especially with internal positioning markings on a wrapping material strip, such as print marks, and the mechanical constraints in the format area, the angle of incidence is too shallow, meaning too little light from the object reaches the receiving optics of the conventional sensor. A mechanical hold-down device and the guidance of the still loose segments also complicate the integration of conventional sensors.

According to the invention, the light exit is formed by at least one optical fiber. Using optical fibers, for example, based on fiber optics, optical detection can be advantageously implemented with minimal installation space. The compact design allows for a measuring distance and angle of incidence that enable reliable measurement without the need for additional optical elements.

The at least one light exit is preferably arranged in direct measuring relationship with the surface to be measured. In the context of this application, "direct measuring relationship" means that the light exiting the light exit falls directly onto the object to be examined (segment or cladding strip), without any optical elements such as lenses, filters, or the like arranged in the beam path.

Preferably, the measuring device is configured to perform at least one point and/or rectangular reflection measurement. Optical reflection measurements can be performed with comparatively little effort compared to optical transmission measurements, which, depending on the material being examined, do not always function reliably. A point measurement means that only the light intensity reflected by a point or light spot is determined, rather than the laborious capture and evaluation of a two-dimensional image consisting of a large number of pixels, for example, using a camera.

According to the invention, the measuring device comprises a first light exit arranged in a measuring relationship with the segment string. This advantageously allows the (axial) positions of the individual segments along the conveying direction and/or the lengths of the segments, in particular of different segments with different properties, to be determined. For this purpose, the segments advantageously differ in color.

According to the invention, the measuring device comprises a second light exit arranged in a measuring relationship with the wrapping strip. This advantageously allows optical differentiation of markings or print marks on the wrapping strip, in particular on the inside of the wrapping strip, from which the position of the wrapping strip relative to the segments can advantageously be determined. For this purpose, the markings or print marks advantageously differ from the color of the wrapping strip.

Preferably, the light exits are arranged at an angle in the range between 0° and 180°, more preferably between 50° and 110°, to each other. This advantageously enables reliable detection of both the segments and markings or print marks on the wrapping paper with sufficiently steep light incidence angles.

Preferably, each light exit is generated by an associated transmitting optical fiber, whereby, in particular, each transmitting optical fiber can be associated with a corresponding receiving optical fiber. In a preferred embodiment, the at least one optical fiber is advantageously held in a fiber optic head. In this case, the transmitting optical fiber and the corresponding receiving optical fiber are preferably arranged in a common exit opening of the fiber optic head. With such a design, optical detection with the desired functionality can be realized in the smallest possible space.

In an advantageous embodiment, the fiber optic head is attached to a hold-down device for holding down the segments. Since the hold-down device is in a fixed spatial relationship to the segments, this easily ensures that the fiber optic head is also in a fixed spatial relationship to the multi-segment strand. This is advantageous for reliable and accurate optical measurement.

The fiber optic head can be attached to the hold-down device directly or indirectly, for example, via a support element. In one embodiment, the fiber optic head is guided through an opening in the hold-down device, which can be particularly space-saving. The fiber optic head, which is, for example, tubular or pin-shaped, is preferably arranged at an angle in the range between 0° and 90°, more preferably between 30° and 60°, to the horizontal. This advantageously enables detection of both the segments and the wrapping strip using a simply constructed fiber optic head.

The invention is applicable to all rod-making machines in the tobacco processing industry for producing multi-segment rods. An advantageous application relates to a rod-making machine for producing multi-segment filter rods. The invention can be used, in particular, for quality assurance with regard to defined segment lengths and/or for possible cutting position monitoring or control. Relative position detection can be advantageously implemented using a corresponding fiber optic arrangement, for example, with contrast or color sensors.

Fig. 1

eine schematische Seitenansicht einer Multisegment-Filterstabherstellmaschine;

Fig. 2

eine perspektivische Ansicht auf den Formatbereich einer Multisegment-Filterstabherstellmaschine;

Fig. 3

ein vergrößerter Auszug aus Figur 2 unter Weglassung des Niederhalters;

Fig. 4

eine perspektivische Schnittdarstellung des Niederhalters mit integriertem Lichtleiterkopf; und

Fig. 5

eine Schnittdarstellung des Lichtleiterkopfs mit zwei Lichtaustritten unter Weglassung des Niederhalters.

The invention will be explained below using preferred embodiments with reference to the attached figures.

Fig. 1

a schematic side view of a multi-segment filter rod manufacturing machine;

Fig. 2

a perspective view of the format area of a multi-segment filter rod manufacturing machine;

Fig. 3

an enlarged extract from Figure 2 omitting the hold-down device;

Fig. 4

a perspective sectional view of the hold-down device with integrated light guide head; and

Fig. 5

a sectional view of the fiber optic head with two light outlets, omitting the hold-down device.

The stranding machine 10 is part of a machine for producing multi-segment filter rods 48, each consisting of a plurality of optically distinguishable filter rod segments 17. In a group-forming device 12 (not shown in detail) arranged upstream of the stranding machine 10, groups of filter segments 17 are assembled and, by means of an insertion device 33, continuously placed longitudinally axially onto a wrapping strip 39 drawn from a reel 37 and provided with glue by means of a gluing device 38. In this way, an initially open multi-segment filter strand 41 is formed from the filter segment groups arranged longitudinally axially. Optically detectable markings or printed marks 30 can be arranged on the inside of the wrapping strip 39. The wrapping strip 39 can, in particular, be a wrapping paper strip.

The wrapping strip 39 and the multi-segment filter strand 41 rest on a strand conveyor in the form of an endless format belt 42 driven by a drive 40. The format belt 42 guides the components 39, 41 through a format 45 or an enclosing device 43, which wraps the wrapping strip 39 completely around the filter strand 41, seals it by gluing, and thus forms an endless, closed multi-segment filter strand 44. This can pass through a seaming plate 46, in which the glued seam is dried by heat input or cooling. Individual multi-segment filter rods 48 are then continuously cut from the multi-segment filter strand 44 by a cutting device 47. and transferred to a downstream discharge conveyor.

In the Figures 2 and 3 The strand machine 10 is shown in a cross-section in the area between the insertion device 33 and the enclosing device 43, in which the filter strand 41 is not yet enclosed by the wrapping paper. In this area, the format 45 has a longitudinal axial recess 49 for receiving and guiding the filter strand 41. In the recess 49, the format belt 45 is placed on the format 45 in a U-shaped cross-section. The wrapping strip 39, in turn, is placed on the format belt 45 in a U-shaped cross-section, with the legs 39a of the wrapping strip 39 projecting upwards over the filter strand 41.

Since suction of the filter strand 41 to the format 45 is not practical due to the format belt 42, a longitudinally axially extending hold-down device 20 is provided, which is inserted into the Figures 2 and 4 is shown. The hold-down device 20, which is, for example, plate- or strip-shaped, is arranged on the format 45 or in the recess 49 of the format 45 to hold down the segments 17 forming the filter strand 41. The hold-down device 20 can be pivotable about a horizontal axis in order to make the format 45 accessible in the event of a malfunction.

In the area between the insertion device 33 and the enclosing device 43, in which the filter strand 41 is not yet enclosed by the wrapping paper, a light guide head 21 is provided, which is part of an optical measuring device 19 (see Figure 4 ) for detecting the segments 17 in the filter strand 41 and/or for detecting markings or print marks 30 on the inside of the wrapping paper 39. The light guide head 21 is advantageously attached to the hold-down device 20, so that due to the fixed spatial relationship between the filter strand 41 and the hold-down device 20, there is also a fixed spatial relationship between the light guide head 21 and the filter strand 41. To attach the light guide head 21 to the plate-shaped hold-down device 20, for example, a holder 15 attached to the hold-down device 20 and extending perpendicularly thereto can be provided. The light guide head 21 is guided at an angle advantageously in the range between 0° and 90°, more preferably between 30° and 60°, even more preferably between 40° and 50°, through an opening 16 in the hold-down device 20 (see Figures 4, 5 ), which allows for a particularly space-saving arrangement.

The light guide head 21 comprises a housing 22, for example, in the shape of a pin or tube, in which light guides 25, 31, 37, 50, which will be explained later, are arranged. The pin shape results in an optimally small design and high stability and protection for the light guides 25, 31, 37, 50. In the event of a product jam, the hold-down device 20, including the light guide head 21 and the flexible light guides 25, 31, 37, 50, can be folded to the side.

In order to detect differences, in particular color differences, on the jacket side of the filter strand 41, which are caused in particular by transitions between the segments 17 in the filter strand 41, the light guide head 21 comprises a first light exit 23 (see Figures 3 and 5 ), through which a first light beam or light cone 24 directed onto the jacket side of the filter strand 41 emerges.

The first light beam 24 is preferably directed vertically, or substantially vertically in the range of +- 20°, downwards and arranged such that it preferably strikes the center of the segments 17 of the filter strand 41. To generate the first light beam 24, a first transmitting light guide 25 is provided (see Figure 4 ), which extends from the first light exit 23 inside the housing 22 and is connected, for example, via a cable 26 to a remotely arranged light source 27. The light source 27 can be any suitable source of visible light, an infrared source and/or UV source.

The first light exit 23 is formed by an end face of the first transmitting light guide 25, which is inclined at a suitable angle to the measuring head axis, preferably in the range between 30° and 60°, more preferably in the range between 35° and 55°, and even more preferably in the range between 40° and 50°. The light exiting the first light exit 23 of the first transmitting light guide 25 falls directly and immediately, i.e., without intervening optical elements such as lenses, filters, etc., onto the surface to be examined—here, the lateral surface of the filter strand 41 or the segments 17. However, it is not excluded that the housing 22 has a transparent exit window that closes the first light exit opening 29.

The light reflected from the surface to be examined falls on a first light inlet 28, which can be arranged adjacent to the first light outlet 23. This thus involves a point-shaped and/or rectangular reflection measurement. The first light outlet 23 and the first light inlet 28 are advantageously arranged together in one and the same outlet opening 29 of the measuring head 21 or the measuring head housing 22.

A first receiving optical fiber 31 is assigned to the first light inlet 28, with which the reflected light entering the measuring head 21 through the first light inlet 28 is guided to an optical sensor 32 arranged remotely, in particular in the region of the light source 27, in order to generate an electrical signal dependent on the intensity of the reflected light.

The optical sensor 32 is expediently matched to the measuring wavelength of the light source 27. It can preferably be a contrast or color sensor. A luminescence or infrared sensor can also be used depending on the requirements. In principle, all sensor principles that are physically connected to optical fibers or are based on other The sensor 32 can be conveniently installed at a suitable location due to the variable length of the optical fibers 25, 31, 37, and 50.

For detecting markings or print marks 30 on the inside of the wrapping strip 39, the light guide head 21 comprises a second light outlet 35 (see Figures 3 and 5 ), through which a second light beam or light cone 36 directed towards the inside of the wrapping strip 39 emerges.

The second light beam 36 is preferably directed approximately horizontally in the range of +- 20° laterally and is arranged such that it preferably strikes the wrapping strip 39 approximately perpendicularly. To generate the second light beam 36, a second transmitting light guide 37 is provided (see Figure 4 ), which extends from the second light exit 35 inside the housing 22 and is connected, for example, via the cable 26 to the light source 27 (or a suitable further light source).

The second light exit 35 is formed by an end face of the second transmitting optical fiber 37, which is inclined at a suitable angle relative to the measuring head axis, preferably in the range between 30° and 60°, more preferably in the range between 35° and 55°, and even more preferably in the range between 40° and 50°. Preferably, the light exits 23, 35 or the light beams 24, 26 form an angle in the range between 50° and 110°, preferably between 60° and 100°, and even more preferably between 70° and 90°.

The light emerging from the second light exit 35 of the second transmitting light guide 37 falls directly and immediately, i.e., without intervening optical elements such as lenses, filters, etc., onto the surface to be examined, here the inside of the enveloping strip 39. However, it is not excluded that the housing 22 has a transparent exit window that closes the second light exit opening 13. The second light exit 35 is advantageously arranged below the upper edge of the enveloping strip 39, which allows for a spatially optimal measurement arrangement.

The light reflected from the surface to be examined falls on a second light inlet 11, which can be arranged adjacent to the second light outlet 35. This also involves a point-shaped and/or rectangular reflection measurement. The second light outlet 35 and the second light inlet 11 are advantageously arranged together in one and the same outlet opening 13 of the fiber optic head 21 or the housing 22.

A second receiving optical fiber 50 is assigned to the second light inlet 11, with which the reflected light entering the optical fiber head 21 through the second light inlet 11 is guided to the optical sensor 32 (or a suitable further sensor) in order to generate a preferably electrical signal dependent on the intensity of the reflected light.

The electrical signals are converted into a digital signal and transmitted to an electronic data processing device 34. The signals are evaluated in the data processing device 34 in order to determine the relative position and/or length of the individual segments 17, and/or a position and/or width detection of an internal mark 30 on the wrapping strip 39, as actual values for downstream monitoring and synchronization tasks. The evaluation can be carried out, for example, by determining one or more rising or falling signal edges. Based on the evaluated signals, process-related material processing, such as cutting position control of the cutting device 47, detection of the object or segment length, and position control, can then be carried out in a controlled and automatic manner and online during the manufacturing process.

In one embodiment, an (error) signal can be generated if the relative assignment of a segment 17 to an inner marking 30 on the wrapping strip 39 exceeds or falls below predetermined limits. The error signal can advantageously be used to eject defective articles, issue a warning to an operator, and/or stop the machine.

The light outlets 23, 35 are preferably flush with the exit surface of the light guide head 21. The cone angle of the beam cone of the light cones 24, 36 is preferably small, in particular less than 70° or 68°, preferably less than 45°, more preferably less than 30°, and preferably 22°. The shape of the light outlets 23, 35 can vary and be, for example, round or square. The light outlets 23, 35 are preferably smoothly polished and can therefore be easily cleaned, for example, in the event of glue deposits, etc.

The optical measuring device 19 comprises the light source 27, the fiber optic head 21, the fiber optics 25, 31, 37, 50 and the optical sensor 32. The fiber optic technology used makes it possible to realize any geometric holders and guides with one or more optical detection points as an online measuring device 19.

Instead of a single fiber optic head 21, a plurality of fiber optic heads may also be provided. For example, one fiber optic head may be provided for each pair of transmit-receive fiber optics. A separate fiber optic head for each fiber optic is also possible.

Claims (12)

1. Strand forming apparatus (10) of the tobacco processing industry for producing multi-segment rods, including a continuously driven garniture tape (42) for conveying a wrapping strip (39) placed on the garniture tape (42) and a number of segments (17) placed on the wrapping strip (39), a wrap-around device (43) for enwrapping the segments (17) with the wrapping strip (39), and an optical measuring device (19) for detecting a property of the multi-segment strand (41) formed from the segments (17) and the wrapping strip (39), wherein the optical measuring device (19) includes at least one light outlet (23; 35) which in the conveying direction is located before the wrap-around device (43), wherein the measuring device (19) includes a first light outlet (23) which is located in correlation with the measurement of the segments (17), characterized in that the at least one light outlet (23; 35) is formed by at least one light guide (25; 37) and that the measuring device (19) includes a second light outlet (35) which is located in correlation with the measurement of the wrapping strip (39).
2. Strand forming apparatus according to claim 1, characterized in that the measuring device (19) is configured to perform at least one punctiform and/or rectangular reflection measurement.
3. Strand forming apparatus according to any one of the preceding claims, characterized in that the light outlets (23, 35) are arranged at an angle in the range between 0° and 180°, in particular between 50° and 110° to each other.
4. Strand forming apparatus according to any one of the preceding claims, characterized in that each light outlet (23, 35) is formed by an assigned transmitting light guide (25, 37), wherein preferably each transmitting light guide (25, 37) is provided with one receiving light guide (31, 50).
5. Strand forming apparatus according to any one of the preceding claims, characterized in that the at least one light guide (25, 31, 37, 50) is mounted in a light guide head (21).
6. Strand forming apparatus according to the claims 4 and 5, characterized in that the transmitting light guide (25; 37) and the corresponding receiving light guide (31; 50) are located in a common outlet aperture (29; 13) of the light guide head (21).
7. Strand forming apparatus according to claim 5 or 6, characterized in that the light guide head (21) is attached to a hold-down device (20) for holding down the segments (17) in the shaping garniture (45).
8. Strand forming apparatus according to claim 7, characterized in that the light guide head (21) is guided through an aperture (16) in the hold-down device (20).
9. Strand forming apparatus according to one of the claims 5 to 8, characterized in that the light guide head (21) is arranged to be inclined to the horizontal at an angle in the range between 0° and 90°, in particular between 30° and 60°.
10. Method for producing multi-segment rods of the tobacco processing industry, including conveying a wrapping strip (39) and a number of segments (17) placed on the wrapping strip (39) by a garniture tape (42), enwrapping the segments (17) with the wrapping strip (39) by means of a wrap around device (43), and optical detection of a property of the multi-segment strand (41) formed from the segments (17) and the wrapping strip (39) by means of an optical measuring device (19), wherein the optical detection is carried out prior to enwrapping the segments (17) with the wrapping strip (39), wherein the optical measuring device (19) includes at least one light outlet (23; 35) which in the conveying direction is located before the wrap-around device (43), wherein the measuring device (19) includes a first light outlet (23) which is located in correlation with the measurement of the segments (17), characterized in that the at least one light outlet (23; 35) is formed by at least one light guide (25; 37) and that the measuring device (19) includes a second light outlet (35) which is located in correlation with the measurement of the wrapping strip (39).
11. Method according to claim 10, characterized in that the electrical signals from the optical detection are evaluated to determine therefrom the relative position and/or length of the individual segments (17), and/or a position and/or width determination of an internal marking (30) on the wrapping strip (39), as actual values for a subsequent monitoring and synchronization function, for example control of the cutting point.
12. Method according to claim 10 or 11, characterized in that a signal is generated as soon as the relative assignment of a segment (17) to an internal marking (30) on the wrapping strip (39) exceeds or falls below predetermined threshold values.

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