GB2543534A

GB2543534A - Apparatus to indicate wear of a cutting edge

Info

Publication number: GB2543534A
Application number: GB1518598.6A
Authority: GB
Inventors: Bilal Farhat Assad
Original assignee: British American Tobacco Investments Ltd
Current assignee: British American Tobacco Investments Ltd
Priority date: 2015-10-20
Filing date: 2015-10-20
Publication date: 2017-04-26
Also published as: GB201518598D0

Abstract

The apparatus has an extraction unit 7 with an upstream section 8 and a downstream section 9; a pressure differential is generated across the web 1 of tipping paper to remove cut paper fragments and determine the proportion of fragments removed in each section. Each section 8,9 may have a chamber in which vacuum pressure is generated above the web to form fluid pathways, with a lower pressure in the second chamber. Each chamber may also have a compressed air outlet 33 on the opposite side of the web 1 to the fluid pathways, with a higher pressure applied in the second chamber. The apparatus may form part of a tobacco industry product manufacturing machine having a detector with a processor receiving signals from sensors in each of the two fluid pathways monitoring the fragments removed, alternatively the fragments may be monitored visually through a window in each chamber. The processor may control an adjustable mount (fig.1,6) to vary the separation of a cutting roller (fig.1,2) and an anvil (fig.1,3), or halt operation of the machine, when the relative proportion of cut fragments removed in the second chamber exceeds a predetermined level.

Description

Apparatus to indicate wear of a cutting edge Technical Field

This application discloses an apparatus to indicate wear of a cutting edge that cuts apertures in a web of tipping paper as it passes through a tobacco industry product manufacturing machine.

Background

During manufacture of some rod shaped articles of the tobacco industry such as smoking articles, it is necessary to remove parts of a web of paper to form apertures or similar openings. For example, one application is the formation of ventilation apertures in tipping paper, To achieve this, a crush-cutting system can be used that cuts a pattern using a cutting roller having a mechanical cutting edge that is pressed against a hard flat or profiled anvil to cut the web as it passes in between. In a crush-cutting system the cutting edge does not pass all the way through the thickness of the web, leaving a portion to be separated by the crushing action or weakened to an extent that the cut fragments fall out of the web. In some instances, the cutting edge may only pierce 75% of the thickness of the paper and the remaining 25% bursts due to the pressure of the cutting edge on the paper. To extract the cut fragments, which are waste, an air pressure extraction system is provided downstream of the cutter. The effectiveness of the cut t ing is determined by the sharpness of the cutting edge and by the pressure that the cutting roller applies against the anvil. The cutting pressure is provided by an adjustable mount that presses the cutting roller and anvil together.

Summary

In accordance with some embodiments described herein, there is provided apparatus to indicate wear of a cutting edge used to cut apertures in a web of tipping paper as it passes through a tobacco industry product manufacturing machine, the apparatus comprising an extraction unit to generate a differential air pressure across the web as it passes through the extraction unit from an upstream section to a downstream section to remove paper fragments cut from the web by the cutting edge, the upstream and downstream sections being separated from each other so thatthe relative proportion of paper fragments removed from the web in the upstream and downstream sections can be d etermined, an increase in the proportion of paper fragments removed from the web in the downstream section being indicative of wear in the cutting edge.

The upstream section may comprise a first chamber through which the web travels, the first chamber haring a first fluid pathway for the passage of paper fragments removed from the web as it passes through said first chamber in response to the generation of a vacuum pressure applied to said first fluid pathway.

The downstream section may comprise a second chamber through which the web travels after exiting the first chamber, the second chamber having a second fluid pathway for the passage of paper fragments removed from the web as it passes through the second chamber, and which have not been removed from the web as it passes through the first chamber, in response to the generation of a vacuum pressure applied to said second fluid pathway.

The apparatus for indicating wear of a cutting edge may further comprise a detector to detect an increase in the proportion of paper fragments being removed from the web in the downstream section relative to the upstream section.

The detector may comprise a sensor to generate a signal indicative of an amount of cut paper fragments in the second fluid pathway.

The detector may comprise a sensor disposed in each of said first and second fluid pathways, each sensor being operable to generate a signal indicative of an amount of cut paper fragments in a respective fluid pathway.

The apparatus for indicating wear of a cutting edge may further comprise a processor to receive a signal generated by the or each sensors.

The vacuum pressures applied to each of said first and second fluid pathways may be the same.

The vacuum pressure applied to the second fluid pathway maybe lower than the pressure applied to the first fluid pathway.

The apparatus for indicating wear of a cutting edge may further comprise an airflow generator to apply a vacuum pressure to each of said first and second fluid pathways.

The first and second fluid pathways maybe configured so that a vacuum pressure is generated in each of said first and second chambers in a region above the web as it passes through each of said first and second chambers.

The apparatus for indicating wear of a cutting edge may further comprise a compressed air outlet operable to blow air towards a web as it travels through the first and second chambers, said compressed air outlet being on an opposite side of the web to the first and second fluid pathways.

The pressure of the compressed air blown towards the web in each of the first and second chambers may be the same.

The pressure of the compressed air blown towards the web may be greater in the second chamber than in the first, chamber.

The apparatus may comprise a window or similar viewing port in the first and second chambers. This enables an increase in the proportion of the paper fragements that are being removed in the in the downstream section relative to the upstream section to be visually determined.

In accordance with one embodiment of the invention there is provided a tobacco industry product manufacturing machine comprising the apparatus described above.

The tobacco industry product manufacturing machine may comprise an adjustable cutting mechanism, the processor being configured to adjust the adjustable cutting mechanism when the detector d etects that an increase in the proportion of cut fragments that are being removed in the second chamber exceeds a predetermined level.

The processor may be configured to halt operation of the tobacco industry product manufacturing machine when the detector detects that an increase in the proportion of cut fragments that are being removed in the second chamber exceeds a predetermined level.

According to the invention there is also provided a method for indicating wear in a cutting edge used to cut apertures in a wreb of tipping paper as it passes through a tobacco industry product manufacturing machine, the method comprising generating a differential air pressure across the web as it passes through an extraction unit from an upstream section to a downstream section to remove paper fragments cut from the web by the cutting edge and, determining the relative proportion of paper fragments removed from the web in the upstream and downstream sections.

As used herein, the term “smoking article” includes smokeable products such as cigarettes, cigars and cigarillos whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes and also heat-not-burn (HnB) products, and other nicotine deliver}-' products such as aerosol generation devices including e-cigarettes. The smoking article maybe provided with a filter for the gaseous flow drawn by the smoker. A tobacco industry product refers to any item made in, or sold by the tobacco industry, typically including a) cigarettes, cigarillos, cigars, tobacco for pipes or for roll-your-own cigarettes, (whether based on tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes); b) non-smoking products incorporating tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes such as snuff, snus, hard tobacco, and heat-not-burn (HnB) products; and c) other nicotine-delivery systems such as inhalers, aerosol generation devices including e-cigarettes. This list is not intended to be exclusive, but merely illustrates a range of products which are made and sold in the tobacco industry.

In the context of this specification the term upstream refers to a position in the which is closer to the cutting mechanism relative to a downstream position, which is further away from the cutting mechanism. The web travels in a direction away from the cutting mechanism from an upstream to a downstream position.

In the context of this specification the term vacuum pressure refers to a pressure below atmospheric pressure.

Brief Description of the Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure i is an isometric view of a first embodiment according to the invention;

Figure 2 is a cross section view of an air flow generator for generating a differential air pressure across the web in the extraction chamber;

Figure 3 is a side elevation view of another embodiment according to the invention; Figure 4 is a side elevation view of yet another embodiment according to the invention.

Detailed Description A problem occurs due to wear of the cutting edge or poor calibration of the adjustable mount, as this can cause the web to be improperly cut, so that cut-out fragments remain in the web despite passing through the air pressure extraction system.

Embodiments of the present invention seek to provide an early indication that a cutting edge has worn and cutting performance is declining so that it can be corrected or so that the cutting mechanism can be replaced or repaired, such as by re-grinding the cutting edge or by manual or automatic adjustment of the cutting edge.

Figure 1 shows a first, embodiment of the invention in which a web 1 of material is drawn continuously between a pair of cylindrical rollers 2/3. An upper roller 2 is positioned above the web 1 while a lower roller 3 is positioned below the wreb 1. The upper and lower roller 2/3 have axes that lie in a common plane arranged perpendicular to the direction of travel of the web 1, such that the rollers 2/ 3 are parallel and the upper roller 2 is positioned directly above the lower roller 3, in the depicted embodiment, the upper roller 2 is a crush cutting roller 2 and the lower roller 3 is an anvil roller 3. The crush cutting roller 2 comprises a cutting edge 4 embedded into its curved surface so that a sharpened tip of the cutting edge 4 protrudes from the curved surface. The cutting edge 4 has a profile corresponding to the shape of a window or aperture 5 to be cut from the web 1 of material. Preferably, multiple cutting edges 4 are embedded into the surface of the roller 2 and distributed around the circumference of the roller 2.

In operation, the cutting roller 2 is positioned so that as it rotates, the tip of the cutting edge 4 passes a distance from the curved surface of the anvil roller 3 that is less than the width of the web 1 of material passing in between, The cutting roller 2 and the anvil roller 3 are configured to rotate with a peripheral speed substantially the same as the speed of the web 1 of material . Therefore as the web 1 of material is drawn between the rollers 2/3, the web 1 is intermittently crushed between the tip of the cutting edges 4 embedded in the cutting roller 2 and the curved surface of the anvil roller 3 to crush cut a pattern into the web 1 corresponding to the profile of the cutting edges 4, the pattern defining paper fragments to be removed to create the apertures 5.

An adjustable mount 6 is mechanically coupled to the cutting roller 2 and arranged to control the separation between the cutting roller 2 and the anvil roller 3. As the cutting edge 4 on the cutting roller 2 begins to wear, the adjustable mount 6 can be configured to move the cutting roller 2 closer to the anvil roller 3 to maintain a predetermined distance between the tip of the cutting edge 4 and the curved surface of the anvil roller 3, thereby maintaining an effective cut. Alternatively, the adjustable mount can be configured to be manually adjusted by an operator.

In the illustrated embodiment, the adjustable mount 6 comprises a hydraulic actuator in order to cause the adjustment of the separation distance between the tip of the cutting edge 4 and the anvil roller 3. According to unillustrated embodiments, the adjustable mount, 6 may comprise a pneumatic actuator that, exerts a force on the cutting roller 2 toward the anvil roller 3 so that the web 1 displaces the cutting roller 2 as it passes in between to create a cutting pressure at the tip of the cutting edge 4, the pressure being adjustable by pressure adjusting screw or similar. Equally, the cutting pressure could be effected by a spring and the spring force adjusted by a threaded tensioner (not shown) to change the cutting pressure.

The action of crushing the web 1 of material with the cutting edge 4 of the cutting roller 2 causes the material to weaken in the crushed region so that the pattern formed in the web 1 by the cutting roller 2 forms a line of weakness that causes the paper fragments to either drop out of the web 1 under their own weight or, enable them to be easily removed from the web 1 in response to the generation of a pressure differential across the web.

An extraction unit 7 is disposed immediately downs tream of the rollers 2,3 for removing the paper fragments from the web 1 of material. Embodiments of the invention provide a two-stage paper fragment extraction system. In the embodiment shown in Figure 1, the extraction station 7 comprises an upstream chamber 8 and a downstream chamber 9. The downstream chamber 9 is positioned further away from the rollers 2, 3 than the first upstream chamber 8 and in the direction of travel of the web 1. The web 1 of material passes through the rollers 2,3 and into the upstream chamber 8, whereupon a first pressure differential is applied across the web i to cause paper fragments to be removed from the web 1. As the web i continues to travel through the extraction unit 7, it passes from the upstream chamber 8 into the downstream chamber 9, whereupon a second pressure differential is generated across the web 1 to remove any paper fragments that have not already been removed in the upstream chamber 8.

The first and second pressures may be less than atmospheric pressure so that the paper fragments are blown upwardly by a pressure differential between opposite sides of the web 1.

An opening 10,10’ in each chamber 8, 9 is provided for the extraction of the paper fragments. In the illustrated embodiment, the opening 10,105 is in fluid communication with an airflow generator (see Figure 2) configured to draw air through the opening 10, 10’. By this method a low pressure is generated in a region above the web 1 relative to a region beneath the web 1.

As shown, each chamber 8,9 is arranged to enclose an area immediately above the upper surface of the web 1 and comprises four walls, two side walls 11,12, an end wall 13 and a top wall 14. The side walls 11,12 upstand perpendicular to the surface of the web 1 and extend parallel to the direction of travel of the web 1, with each side wall 11,12 positioned in close proximity to opposite edges 15,15’ of the web 1. The space between the edges 15,15’ of the web 1 and inner faces of the side walls 11,12 is necessarily small to minimise the flow of air around the edges 15/15’ of the web 1 when air is drawn through the opening 10,10’ of the associated chamber 8,9. This has the effect of maximising the pressure acting on the paper fragments to be removed from the web 1.

The top wall 14 extends between upper edges of the side walls 11,12, while the end wall 13 extends to enclose an upstream end 16 of the first chamber 8, connecting outer edges of the top wall 14 and side walls 11,12. The end wall 13 has a lower edge 17 in close proximity to the upper surface of the web 1 to minimise the flow of air into the chamber 8 from the upstream end 16 of the chamber 8 when air is drawn from the chamber 8. The chambers’ 8,9 walls can be made from a transparent material such as Perspex, or a window or other viewing port can be provided in a wall, so that an operator can observe the extraction of paper fragments from the chambers 8, 9.

The second chamber 9 is separated from the first chamber 8 by a duct 18 which forms the extraction opening 10 in the first chamber 8. The duct 18 is connected to a first section of pipe 19 which forms part of a fluid pathway that connects the duct 18 to the airflow generator, The duct 18 is square in section and has a frusto pyramidal shape that forms the walls of the duct 18 and acts as a funnel to channel the paper fragments into the first section of pipe 19. The walls of the duct 18 extend outwardly from the pipe 19 into con tact with inner faces of the chamber 8 walls 11/12/14 to define the opening 10 in the chamber 8. A lower edge 20 of the duct 18 is positioned in close proximity to the upper surface of the web 1 to minimise the flow of air between the first and second chambers 8/9. It will be appreciated that in an alternative embodiment, the first and second chambers 8,9 may be separated from each other by a simple dividing wall and. the duct could instead be mounted so that the extraction opening 10 in the first chamber 8 is formed in the top or side wall of the first chamber 8.

The first section of pipe 19 extends from the back of the duct 18 to the top wall 14 of the second chamber 9. An opening in the top wall 14 allows the passage of air and paper fragments transported by the first section of pipe 19, The first section of pipe 19 is bolted to an inner face of the top wall 14 to form an airtight seal around the opening in the top wall 14. A second section of pipe 21 is aligned with the first 19 and bolted to an outer face of the top wall 14 to create an airtight pathway to a third section of pipe 22. The third section of pipe 22 has a flexible wall to allow it to be routed as necessary to the airflow generator; the third section of pipe 22 can be fitted to the second section 21 by jubilee clip or other suitable means. A second duct 18’ forms the extraction opening 10’ into the second chamber 9. As with the first chamber 8, the duct 18 is fluidly connected to the airflow generator. A fourth section of pipe 23 extends from the duct 18’ and forms part of a fluid pathway that connects the duct 18’ to the airflow' generator. The duct 18’ is the same as the duct 18 described above, so that walls of the duct 18’ extend outwardly from the pipe 23 into contact with inner faces of the chamber 9 walls 11,12,14 to define the opening io\ The opening 10’ is disposed in an upstream end 24 of the second chamber 9. The fourth section of pipe 23 has a flexible wall so that it can be easily routed to the airflow generator. Although the duct 18’ is shown as forming an end wall of the second chamber 9, it will be appreciated that in an alternative embodiment, it can be mounted in a top or side wall of the second chamber 9 and the end wall can be closed by a wall. A cross section view of an example airflow generator 25 is shown in Figure 2. The airflow generator 25 comprises an air permeable bag 26 fluidly connected to the first and second chambers 8/9 so that paper fragments 27 transported from the first and second chambers 8/9 are collected in the bag 26 in similar fashion to a vacuum cleaner. The airflow generator 25 further comprises an air impermeable outer casing 28 to enclose the bag 26, the casing 28 having an opening 29 that leads into the bag 26 and an opening 30 through which air devoid of paper fragments 27 is exhausted. The casing 28 also comprises a mount for a fan 31 configured to draw air out of the casing 28 through the exhaust 30. By drawing air out of the casing 28, the pressure inside the casing 28 drops and air is drawn into the casing 28 from the first and second chambers 8,9 to cause said first and second pressures. The flow of air from the first and second chambers 8,9 to the exhaust 30 carries with it the paper fragments 27 removed from the web, so that said paper fragments 27 are directed by the walls of the ducts 18,18’ into corresponding pipes 19,23,

In another unillustrated embodiment of the invention, the airflow generator 25 does not comprise an air permeable bag 26, but instead comprises an alternative means for collecting the paper fragments 27. For example, the airflow generator 25 may comprise a cyclonic separator for separating the cut parts 27 from the airflow, the cyclonic separator being configured to drop the paper fragments 27 into a bin.

In any embodiment of the invention, the first, and second pressures may be the same. In such an embodiment, paper fragments 27 that are not removed in the first chamber 8 are removed in the second chamber 9 by prolonged exposure to the pressure differential between the lower and upper sides of the web 1.

Alternatively, in another embodiment of the invention, the second pressure is lower than the first pressure so that paper fragments 27 not removed in the first chamber 8 are removed in the second chamber 9 by exposure to an increased pressure differential between upper and lower sides of the web 1. The increased pressure differential results in increased force acting on the paper fragments 27 so that the probability of them being removed from the web 1 is increased.

The lower second pressure can be caused by connecting the duct 18’ of the second chamber 9 to a separate, second airflow generator comprising a fan configured to displace a greater mass flow of air. Alternatively, the lower second pressure can be caused by an alternative means, for example by throttling flow extracted from the first, chamber 8,

Sensors (not shown) are provided to generate a signal to indicate the number or a relative proportion of paper fragments 27 that are passing through each of the openings 10.10’ in the first and second chambers 8,9 in any given timeframe. By determining the quantity of paper fragments 27 that are being extracted via the first chamber 8 compared with the quantity of paper fragments 27 that are being extracted via the second chamber 9, it is possible to determine information about the cutting effectiveness of the crush cutting roller 2. When the crush cutting roller 2 is working well, little to no paper fragments 27 should be extracted via the second chamber 9 as they are easily and readily removed in the first chamber 8. If the crush cutting performance of the roller 2 deteriorates, proportionally more paper fragments 27 are extracted via the second chamber 9 as the sub-standard cut means that they are not so easily and readily removed in the first chamber 8. This way, the crush cutting roller 2 can be adjusted to maintain cutting performance before the cutting performance deteriorates to the point that paper fragments 27 remain in the web 1 downstream of the extraction station 7.

It, will be appreciated that it is not necessary to determine an exact number of paper fragments extracted via the first and second chambers 8,9. Fundamentally, it is sufficient to simply determine whether more paper fragments are being extracted via the second chamber 9 relative to an amount of paper fragments being extracted via the first, chamber 8, as this is sufficient, to enable an operator to ascertain that the cutting performance has begun to deteriorate.

The pressure generated across the web can be determined and set so that when the cutting edge is new or in an optimum condition all the paper fragments, or the vast majority7 of them, wall be extracted by the pressure differential in the first chamber 8. As the cutting edge begins to wear, fragements will then begin to be extracted in the second chamber 9. It may be considered acceptable for some paper fragements to be extracted in the second chamber 9 but when the number of paper fragements extracted in the second chamber 9 relative to those extracted in the first chamber 8 exceeds a certain level, the blade needs to be adjusted or replaced. For example, this may be when more paper fragments start to be extracted in the second chamber 9 relative to the first chamber 8.

The adjustable mount 6 can be configured to adjust the position of the cutting roller 2 in response to information generated by the sensors. For example, when the quantity of paper fragments 27 being extracted via the second chamber 9 is determined to be above a critical value, the adjustable mount 6 can automatically activate to move the cutting roller 2 closer to the anvil roller 3 or to increase the cutting pressure. Therefore, as the cutting edge 4 embedded in the cutting roller 2 wears, the loss in cutting performance can be compensated for by moving the cutting roller 2 closer to the anvil roller 3 to maintain a set separation distance or cutting pressure between the cutting edge 4 tip and the anvil roller 3.

In another example of this embodiment, the adjustable mount 6 is configured to adjust the separation distance or cutting pressure between the cutting edge 4 tip and the anvil roller 3 when the quantity of paper fragments 27 being extracted by the first chamber 8 is determined to be below a critical value. A processor is also provided and configured to receive the signals generated by the sensors to determine if the critical value has been met, the processor being further configured to then transmit a signal to the adjustable mount 6 to cause the adjustment of the separation or cutting pressure between the cutting edge 4 tip and the anvil roller 3-

The cutting edge 4 tip and anvil 3 separation distance may be reduced or the cutting pressure increased by a predetermined value corresponding to the expected amount of wear on the cutting edge tip associated with the critical value being reached. Therefore the critical value can be programmed into the processor, with the degree of displacement of the cutting roller 2 by the adjustable mount made in response set accordingly. An upper level of accepted wear is also set; this corresponds to a total permitted displacement of the cutting roller 2 by the adjustable mount 6. The processor is configured to transmit an alert signal when the total permitted displacement of the cutting roller 2 is reached to indicate that the cutting roller 2 requires replacement.

In an alternative embodiment, the processor can be configured to receive the signals generated by the sensors to d etermine if the critical value has been met, and to then generate an alert signal which is relayed to an operator’s station (not shown). In such an embodiment, the operator can adjust the adjustable mount manually in order to maintain the necessary separation distance or cutting pressure between the cutting edge 4 tip and the anvil roller 3. The operator may equally well choose another maintenance option, such as cleaning the cutting edge s 4 in order to maintain cutting performance.

The processor may also determine from the signals generated by the sensors if the quantity of paper fragments 27 being extracted from the first chamber 8 in combination with the quantity of paper fragments 27 being extracted from the second chamber 9 falls below a required value, the value being indicative of the total number of paper fragments 27 to be removed from the web 1 in any given time frame. Therefore, it can be determined if all the paper fragments 27 have been removed from the web 1 before it passes out from the extraction station 7. The processor is configured to transmit an alert signal if the total number of paper fragments 27 being removed from the chambers 8/9 falls below the required value.

In another embodiment, of the in vention shown in Figure 3, the extraction station 7 further comprises a compressed air source 32 in fluid communication with an array of air jets 33. The compressed air source 32 comprises a compressor to generate a pressurised air stream. The pressurised air stream is distributed through a manifold 34 to the array of air jets 33, with each air jet 33 fluidly connected to an opening of the manifold 34.

The air jets 33 are arranged to direct a stream of air at the underside of the web 1 as the web passes through the first and second chambers 8/9. The air jets 33 are arranged longitudinally with respect to the web 1 so that the web 1 is subject to the stream of air for substantially the full time it is resident in the first or second chamber 8/9, The stream of air hits the underside of the web 1 so that the force of the air hitting the web 1 assists in the upward removal of the paper fragments 27.

Preferably, the air jets 33 arranged under the portion of web t passing through the second chamber 9 are configured to deliver higher velocity air at the underside of the web t than the jets 33 arranged under the portion of web i passing through the fi rst chamber 8. This increases the force acting on the underside of the web 1 in the second chamber 9 to assist with the removal of paper fragments 27 that were not removed in the first chamber 8. The velocity of air passing through the air jets 33 may be increased by known means, such as by modifying the geometry of the air jets 33 or by connecting the jets 33 to a separate compressor (not shown) capable of delivering higher pressure air.

In yet another embodiment of the invention shown in Figure 4, the extraction station 7 comprises a first hood 35 and a second hood 36. The second hood 35 is positioned downstream of the first hood 36. The web 1 of material passes between the cutting roller 2 and the anvil roller 3 and under the first hood 35, whereupon a first pressure is applied to the upper surface of the web 1 to cause the paper fragments 27 to be removed from the web 1. The web passes directly from under the first hood 35 to pass under the second hood 36, whereupon a second pressure is applied to the upper surface of the web 1 to remove any paper fragments 27 that were not removed by the fi rst hood 35.

Preferably the first and second pressures are less than atmospheric pressure so that the paper fragments 27 are blown upwardly by a pressure differential bet ween the underside of the web 1, which will be substantially atmospheric pressure, and the upper si de of the web 1 to which the first and second pressures are applied.

Each hood 35/36 is in fluid communication with an airflow generator 25 as described above, wherein like features retain the same reference numerals. By this method the first, and second pressures are applied to the upper surface of the web 1. A compressed air source 32 and an array of air jets 33 may be provided as described above, wherein like features retain the same reference numerals. The air jets 33 are arranged to direct a stream of air at the underside of the web 1 as the web 1 passes under the first and second hoods 35/36. The air jets 33 arranged under the portion of web 1 passing under the second hood 36 may be configured to deliver higher velocity air at the underside of the web 1 than the jets 33 arranged under the portion of web 1 passing under the first hood 35. This increases the force acting on the underside of the web 1 under the second hood 36 to assist with the removal of any paper fragments 27 that were not removed under the first hood 35.

As shown, each hood 35/36 comprises an opening 37/37’ arranged proximate to the upper surface of the web 1. Air and paper fragments 27 are drawn through the opening 37/37’ arid into the hood 35/36 by the airflow generator 25. Hood walls extend convergentlv from the opening 37/37’ to a pipe 38/38’ that connects the hood 35/36 to the airflow generator 25. The hood 35/36 walls direct the airflow and paper fragments 27 into the pipe 38/38’. Each hood 35/36 is therefore configured to duct air adjacent the upper surface of the web 1 through the opening 37/37’ and into the pipe 38/38’ leading to the airflow generator 25, the paper fragments 27 being transported away from the web 1 by the resultant airflow.

Sensors and a processor maybe provided as described above, wherein like features retain the same reference numerals.

The sensors can be provided in combination with any of the embodiments shown i n Figures 1 to 3. In any of these discussed embodiments, the sensors are preferably arranged with a sensor in each of the two pipes 22/23/38/38’ connecting the extraction station 7 to the airflow" generator 25. The sensors may be optical sensors and comprise a radiation source, such as a source of coherent light, and a light detector. The light is directed through the pipe 22/23/38/38’ in a plane perpendicular to the direction of flow of air and paper fragments 27. The light detector is arranged directly opposite the source of coherent light so that light impinges on the detector. Therefore, each time a cut part 27 passes through the beam of coherent light a signal is generated by the light detector. The change in signal is recorded against time to give an indication of the flow rate of paper fragments 27 passing through the pipe 22/23/38/38’. Therefore, the greater the flow rate of paper fragments 27 passing through the pipe 22/23/38/38’, the greater the frequency at which the signal changes. The processor monitors this frequency to determine if the number of paper fragments being extracted is greater or less than the critical value.

In order to address various issues and advance the art, the entirety of this disclosure shows by way of illustration various embodiments in which the claimed invention may be practiced and provide for superior apparatus for the manufacture of rod shaped articles. The advantages and features of the disclosure are of a representative sample of embodiments only, and are not exhaustive and/or exclusive. They are presented only to assist in understanding and teach the claimed features. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects of the disclosure are not to be considered limi tations on the disclosure as defined by the claims or limitations on equivalents to the claims, and that other embodiments maybe utilised and modifications may be made without departing from the scope of the disclosure. Various embodiments may suitably comprise, consist of, or consist essentially of, various combinations of the disclosed elements, components, features, parts, steps, means, etc. In addition, the disclosure includes other inventions not presently claimed, but which may be claimed in future.

Claims

Claims

1. Apparatus to indicate wear of a cutting edge used to cut apertures in a web of tipping paper as it passes through a tobacco industry product manufacturing machine, the apparatus comprising an extraction unit to generate a differential air pressure across the web as it passes through the extraction unit from an upstream section to a downstream section to remove paper fragments cut from the web by the cutting edge, the upstream and downstream sections being separated from each other so that the relative proportion of paper fragments removed from the web in said upstream and downstream sections can be determined, an increase in the proportion of paper fragements removed from the web in the downstream section being indicative of wear in the cu tting edge.
2. Apparatus according to claim i, wherein the upstream section comprises a first chamber through which the web travels, the first chamber having a first fluid pathway for the passage of paper fragments removed from the web as it. passes through said first chamber in response to the generation of a vacuum pressure applied to said first fluid pathway.
3. Apparatus according to claim 2, wherein the downstream section comprises a second chamber through which the web travels after exiting the first chamber, the second chamber having a second fluid pathway for the passage of paper fragments removed from the web as it passes through the second chamber, and which have not been removed from the web as it passes through the first chamber, in response to the generation of a vacuum pressure applied to said second fluid pathway.
4. Apparatus according to claim 3, comprising a detector to detect an increase in the proportion of paper fragments being removed from the web in the downstream section relative to the upstream section.
5. Apparatus according to claim 4, wherein the detector comprises a sensor to generate a signal indicative of an amount of cut paper fragments in the second fluid pathway.
6. Apparatus according to claim 5, wherein the detector comprises a sensor disposed in each of said first and second fluid pathways, each sensor being operable to generate a signal indicative of an amount of cut paper fragments in a respective fluid pathway.
7. Apparatus according to claim 5 or 6, comprising a processor to receive the signal generated by the or each sensor.
8. Apparatus according to any of claims 3 to 7, wherein the vacuum pressure applied to each of said first and second fluid pathways are the same.
9. Apparatus according to any of claims 3 to 7, wherein the vacuum pressure applied to the second fluid pathway is lower than the pressure applied to the first fluid pathway.
10. Apparatus according to any of claims 3 to 9, comprising an airflow generator to apply a vacuum pressure to each of said first and second fluid pathways.
11. Apparatus according to any of claims 3 to 10, wherein the first and second fluid pathways are configured so that a vacuum pressure is generated in each of said first and second chambers in a region above the web as it passes through each of said first and second chambers.
12. Apparatus according to any of claims 3 to 11, comprising a compressed air outlet operable to blow air towards a web as it travels through the first and second chambers, said compressed air outlet, being on an opposite side of the web to the first and second fluid pathways.
13. Apparatus according to claim 12, wherein the pressure of the compressed air blown towards the web hi each of the first and second chambers is the same.
14. Apparatus according to claim 12, wherein the pressure of the compressed air blown towards the web is greater in the second chamber than in the first chamber.
15. Apparatus according to any of claims 3 to 14, comprising a window in the first and second chambers to enable an increase in the proportion of the paper fragments removed in the in the downstream section relative to the upstream section to be determined visually. ιό. A tobacco industry product manufacturing machine comprising the apparatus according to any preceding claim.
17. A tobacco industry product manufacturing machine according to claim 16, when dependent on claim 7, comprising an adjustable cutting mechanism, the processor being configured to adjust the adj ustable cutting mechanism when the detector detects that an increase in the proportion of cut fragments removed in the second chamber relative to the first chamber exceeds a predetermined level.
18. A tobacco industry product manufacturing machine according to claim 16, when dependent on claim 7, wherein the processor is configured to halt operation of the tobacco industry product manufacturing machine when the detector detects that an increase in the proportion of cut fragments removed in the second chamber relative to the first chamber exceeds a predetermined level.
19. A method of indicating wear in a cutting edge used to cut apertures in a web of tipping paper as it passes through a tobacco industry product manufacturing machine, the method comprising generating a differential air pressure across the web as it passes through an extraction unit from an upstream section to a downstream section to remove paper fragments cut from the web by the cutting edge and, determining the relati ve proportion of paper fragements removed from the web in the upstream and downstream sections.