The present invention relates to an apparatus for flattening a sheet of material, a packaging machine comprising the apparatus and to a method of flattening a sheet of material.

Background

The presence of surface irregularities in sheet material is a known issue. In particular, when a laminate sheet material is manufactured, it may have a non-uniform thickness. The sheet material may be spooled and, when it is unwound for use in wrapping bundles of cigarettes, the lack of uniformity may become visible in the form of wrinkles or waviness in the surface of the material. Summary

In accordance with some embodiments described herein, there is provided an apparatus for flattening a sheet of material as it is unwound from a spool and conveyed along a conveyance path, comprising a rotatably mounted heating roller and a heating element for heating the heating roller, the heating roller being positionable in rolling contact with a surface of the sheet of material as it is conveyed along said conveyance path such that the sheet of material is heated by the heating roller.

The heating roller may comprise a tubular body having a longitudinal axis. The apparatus may comprise a heating roller support, the tubular body may be mounted to the heating roller support such that the tubular body is freely rotatable about said longitudinal axis relative to said heating roller support.

The heating roller support may comprise a base and a pair of mounting plates upstanding from said base, the tubular body may extend between and be rotatably mounted to each of said mounting plates.

The heating element may be received within the tubular body. The heating element may extend in a direction along said longitudinal axis. The heating element may be configured to rotate together with the tubular body.

The heating element may comprise cables extending therefrom and which may extend from an end of the tubular body when the heating element is received therein.

The cables may comprise power supply cables for supplying power to the heating element to heat the heating roller.

Optionally, the heating element may include a temperature sensor for detecting a temperature of the heating element.

The cables may include a data cable to carry a signal indicative of the temperature detected by the temperature sensor. The apparatus may comprise a slip ring having a rotatable hub extending towards said tubular body along said longitudinal axis, said rotatable hub may be rotatable about said longitudinal axis together with said tubular body and may have terminals extending therefrom for connection of said cables extending from said heating element to said rotatable hub.

The slip ring may comprise a stationary hub extending in an opposite direction to said rotatable hub, said stationary hub may have terminals extending therefrom, the slip ring may be configured to transmit power and/ or data via the terminals on the rotatable hub to the terminals on the stationary hub.

The apparatus may comprise a terminal housing located between the tubular body and the slip ring and extending in a direction along the longitudinal axis, the terminal housing may be mounted for rotation together with the tubular body. One end of the terminal housing may be mounted to the rotatable hub of the slip ring for rotation together with said rotatable hub.

Optionally, the terminal housing may comprise a cavity into which the terminals on the rotatable hub of the slip ring extend. The cables extending from the heating element may terminate in a connector block for connection to said terminals on said rotatable hub, said cavity in the terminal housing may be configured to receive the connector block. The apparatus may comprise an aperture in the terminal housing to provide access to the cavity and facilitate connection of the connector block to the terminals on said rotatable hub.

The apparatus may comprise a sliding mechanism configured to move the heating roller between a disengaged position, in which the heating roller is spaced from the surface of the sheet of material being conveyed along the conveyance path, and an engaged position, in which the heating roller is in rolling contact with the surface of the sheet of material being conveyed along the conveyance path. The sliding mechanism may comprise a stationary slide rail mountable adjacent to the conveyance path, and a sliding block configured to slide along said stationary slide rail in a direction towards and away from the conveyance path.

Optionally, the base of the heating roller support may be mountable to the sliding block.

The apparatus may comprise a pair of spaced parallel guide rollers, said guide rollers each having a longitudinal axis parallel to the longitudinal axis of the heating roller and maybe positioned such that the sheet of material passes between the guide rollers and the heating roller when moving along the conveyance path.

The heating roller may be positionable between the parallel guide rollers in an engaged position such that the sheet of material is partially wrapped about the heating roller as it travels between the guide rollers.

According to another aspect of the invention, there is provided a packaging machine comprising a drive for conveying a sheet of material along a conveyance path from a spooled supply of sheet material to a mechanism for packaging items in said sheet of material, and the above apparatus configured such that the heating roller is positionable in rolling contact with the surface of said sheet of material being conveyed along said conveyance path. The apparatus may be configured such that the heating roller is movable between a disengaged position in which the heating roller is spaced from the surface of the sheet of material being conveyed along said conveyance path and an engaged position, in which the heating roller is in rolling contact with a surface of said sheet of material being conveyed along said conveyance path.

The packaging machine may comprise a controller. The controller may be configured to move the heating roller into the engaged position when a predetermined operation speed of the packaging machine has been reached.

The controller may be configured to move the heating roller into the engaged position when an operation speed of 50 ppm has been reached.

The controller may be configured to disengage the power to the heating element if a predetermined temperature of the heating element has been detected by the temperature senor of the heating element. The controller may be configured to disengage the power to the heating element when the predetermined temperature of the heating element detected by the temperature sensor is 120°C.

The controller may be configured to control the temperature of the heating element in dependence on an operation speed of the packaging machine.

The temperature of the heating element may be 92°C when the packaging machine is in standby and the heating roller is in the disengaged position. The temperature of the heating element may be ioo°C when the operation speed of the packaging machine is 10 to 150 ppm.

The temperature of the heating element may be no°C when the operation speed of the packaging machine is 150 to 250 ppm. The temperature of the heating element may be 120°C when the operation speed of the packaging machine is greater than 250 ppm.

According to some other embodiments of the invention described herein, there is provided a method of flattening a sheet of material as it is unwound from a spool and conveyed along a conveyance path, comprising positioning a rotatably mounted heating roller in rolling contact with a surface of the sheet of material as it is conveyed along said conveyance path such that the sheet of material is heated by the heating roller. The method may comprise moving the heating roller between a disengaged position in which the heating roller is spaced from the surface of the sheet of material being conveyed along the conveyance path and an engaged position in which the heating roller is in rolling contact with the surface of the sheet of material being conveyed along the conveyance path.

Brief Description of the Drawings

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

Figure 1 shows an apparatus according to an embodiment of the invention; Figure 2A and 2B show an exploded and isometric view respectively of a portion of the apparatus according to an embodiment of the invention;

Figure 3 shows an exploded view of the apparatus according to an embodiment of the invention;

Figures 4A and 4B show the apparatus in a disengaged and an engaged position respectively; and

Figure 5 shows method steps according to an embodiment of the invention.

Detailed Description

Packaging machines are often used in the manufacturing industry and are used to wrap items in a sheet material. It is common for a long length or web of sheet of material to be stored on a spool and when required, to be unwound and conveyed to the packaging machine for packaging the items in the sheet of material.

During the process of manufacturing the sheet of material, the sheet may develop defects or surface irregularities which renders it uneven and which may give it a slightly wrinkled appearance. When the sheet material is spooled, the sheet material is held under tension, any such defects may not be readily apparent. However, they may become apparent in a wrapped product once the material is no longer under tension. The material may appear as a waviness in the material or an irregular surface finish, both of which result in an undesirable appearance to the wrapped product.

In particular, packaging machines are used in the tobacco industry to wrap tobacco industry products in a wrapping material such as metal foil or polymer material. In some instances, a laminate material is used. Particularly, when a laminate sheet material is produced, the laminate sheet can develop surface irregularities such as areas of varying or non-uniform thickness. This can result in the sheet having a wavy appearance in the wrapped tobacco industry product. Therefore, embodiments of the present invention seek to improve the quality of the sheet of material by providing an apparatus for flattening the material by removing, or at least minimising the appearance of, any surface irregularities or defects in the sheet material immediately prior to use. For example, the apparatus may remove defects from the sheet material immediately after it has been unspooled and whilst it is being fed along a conveyance path in a packaging machine, prior to the packaging machine wrapping the sheet material around a product. The problem with surface irregularities or defects in sheet material is predominantly an issue with a double or triple layered laminate structure, and particularly those that include a polymer or polymeric material and a metal as part of the laminate layers. However, it will be understood that the invention is also applicable to any sheet material which suffers from surface defects and which can be removed by the application of heat, irrespective of whether that sheet material is a laminate.

Figure 1 illustrates an apparatus 1 according to an embodiment of the invention and which maybe mounted on or adjacent to a packaging machine so that it can interact with a sheet of material 2 travelling along a conveyance path through the packaging machine. The packaging machine may have a drive configured to convey the sheet of material 2 from a spool (not shown) along a conveyance path through the machine and to a mechanism for wrapping products in the sheet of material 2.

Figure 2A illustrates an exploded view of a portion of the apparatus 1 according to an embodiment of the invention. The apparatus 1 comprises a rotatably mounted heating roller 4 and a heating element 5 configured to heat the heating roller 4 from within. The heating roller 4 is positionable in rolling contact with a surface 3 of the sheet of material 2 as the sheet of material 2 is conveyed along the conveyance path. Since the heating roller 4 is in contact with the surface 3 of the sheet of material 2, the heating roller 4 transfers heat to the sheet of material 2. Heating of the sheet of material 2 removes or at least minimises surface irregularities and defects in the sheet of material 2.

The heating roller 4 is formed from a heat conductive material and comprises a tubular body 6 having a longitudinal axis A. The heating element 5 is cylindrical in shape and is received within the tubular body 6 of the heating roller 4 so as to extend in a direction along the longitudinal axis A of the tubular body 6.

The apparatus 1 comprises a heating roller support 7 comprising a base 8 and a pair of mounting plates 9 upstanding from the base 8. The heating roller 4 extends between and is rotatably mounted to the mounting plates 9 via bearings. Therefore, the heating roller 4 is free to rotate about its longitudinal axis A. Since the heating element 5 is received within the tubular body 6 of the heating roller 6, the heating element 5 rotates together with the heating roller 4 about its longitudinal axis A. As the heating element 5 rotates together with the heating roller 4, a better thermal contact is maintained between the heating element 5 and the heating roller 4.

The heating element 5 comprises cables 10 extending from one end of the heating element 5 and through one of the mounting plates 9 at an end of the tubular body 6. The cables 10 are configured to transmit power to, and data from, the heating element 5. The power cables provide power to the heating element 5 to heat the heating roller 4.

The heating element 5 includes a temperature sensor to detect the temperature of the heating element 5. Signals indicative of the temperature detected by the temperature sensor are transmitted via data cables extending from the heating element 5 and may be used to control the power supplied to the heating element 5 to control the temperature of the heating element 5.

To prevent the cables 10 from twisting as the heating element 5 rotates with the heating roller 4, the apparatus 1 comprises a slip ring 11. The slip ring 11 comprises a rotatable hub 12 which extends towards the tubular body 6 of the heating roller 4 along the longitudinal axis A. The rotatable hub 12 is mounted for rotation about the longitudinal axis A and rotates together with the heating roller 4. The cables 10 extending from the heating element 5 connect to terminals 13 extending from the end of the rotatable hub 12. The slip ring 11 further comprises a stationary hub 14 which extends in an opposite direction to the rotatable hub 12 along the longitudinal axis A. Terminals 13A extend from the stationary hub 14 and the slip ring 11 is configured to transmit power and/ or data via the terminals 13 on the rotatable hub 12 to the terminals 13A on the stationary hub 14 and vice versa. The slip ring itself is a known device. Example slip rings that may be used in embodiments of the invention are M430-K and 430-SS manufactured by Mercotac. The heating roller 4 and the slip ring 11 are separated by a terminal housing 15 that extends in a direction along the longitudinal axis A and is located between one end of the heating roller 4 and the slip ring 11. One end of the terminal housing 15 is mounted to the heating roller 4. The opposite end is mounted to the rotatable hub 12 of the slip ring 11. The terminal housing 15 is mounted for rotation about the longitudinal axis A and rotates together with the heating roller 4 and the rotatable hub 12 of the slip ring 11. The terminal housing 15 spaces the slip ring 11 from the heating roller 4 and supports the slip ring 11.

The terminal housing 15 may be a tubular body and comprise a cavity 16 into which the terminals 13 on the rotatable hub 12 of the slip ring 11 extend. The cables 10 which extend from the heating element 5 comprise a connector block to connect the cables 10 extending from the heating element 5 to the terminals 13 of the rotatable hub 12 of the slip ring 11. The connector block is received within the cavity 16 of the terminal housing 15. Additionally, the terminal housing 15 comprises an aperture 18 which allows access to the cavity 16 and facilitates connection of the connector block to the terminals 13 of the rotatable hub 12 of the slip ring 11.

An isometric view of the assembled heating roller 4, heating element 5, heating roller support 7, slip ring 11 and terminal housing 15 is illustrated in Figure 2B.

As illustrated in Figure 3, the apparatus 4 further comprises a sliding mechanism 19 to which the heating roller 4 is mounted. The sliding mechanism 19 comprises a stationary slide rail 20 positioned adjacent to the sheet of material 2 being conveyed along the conveyance path and a sliding block 21 configured to slide along the stationary slide rail 20 in a direction towards and away from the conveyance path, preferably in a direction perpendicular to the conveyance path. The base 8 of the heating roller support 7 to which the mounting plates 9 are mounted or extend is connected to the sliding block 21. This allows the heating roller 4 to move with the sliding block 21 as it slides along the stationary sliding rail 20. As illustrated in Figures 4A and 4B, the sliding mechanism 19 is configured to move the heating roller 4 between a disengaged position (Figure 4A) and an engaged position (Figure 4B). In the disengaged position, the heating roller 4 is spaced from the surface 3 of the sheet of material 2 being conveyed along the conveyance path, and so is in a non-functional position. In the engaged position, the heating roller 4 is in contact with the surface 3 of the sheet of material 2 being conveyed along the conveyance path, so that, when the heating roller 4 is heated, heat is transferred to the sheet of material 2 to remove or reduce defects in the sheet of material 2. It will be appreciated that the heating roller 4 is free to rotate and is not driven other than by contact with the surface 3 of the sheet of material 2 which is travelling along the conveyance path.

The apparatus further comprises a pair of spaced parallel guide rollers 22 each having a longitudinal axis parallel to the longitudinal axis A of the heating roller 4. The guide rollers 22 are positioned such that the sheet of material 2 passes over the guide rollers 22 and between the guide rollers 22 and the heating roller 4 as the sheet of material 2 travels along the conveyance path. When in the engaged position, the heating roller 4 is positioned between the guide rollers 22 such that the sheet of material 2 is partially wrapped about the heating roller 4 as it travels between the guide rollers 22.

The packaging machine comprises a controller configured to move the heating roller 4 from the disengaged position to the engaged position when a predetermined operation speed of the packaging machine has been reached. For example, when the packaging machine is operating between a speed of o and 50 packs per minute (ppm), the heating roller 4 is in the disengaged position. When the packaging machine is operating faster than an operation speed of 50 ppm, the heating roller 4 is moved by the sliding mechanism 19 into the engaged position where it contacts a surface 3 of the sheet of material 2 as it is conveyed along the conveyance path. At low operation speeds, the surface 3 of the sheet of material 2 may have prolonged contact with the heating roller 4 which may damage the surface 3 of the sheet of material 2. Therefore, by ensuring that the heating roller 4 is only moved into the engaged position once the packaging machine has reached the desired operation speed (50 ppm), the surface 3 of the sheet of material 2 is not overexposed to the heating roller 4 and thus not damaged. The controller is also configured to disengage the power provided to the heating element 5 if a predetermined temperature of the heating element 5 has been detected by the temperature sensor of the heating element 5. The predetermined temperature maybe 120°C.

Additionally, the controller controls the temperature of the heating element 5 as the operation speed of the packaging machine changes. In particular, the temperature of the heating roller 4 maybe controlled so that it increases as the operational speed of the packaging machine increases. For example, when the packaging machine is in standby and the heating roller 4 is in the disengaged position, the temperature of the heating element 5 is 92°C. At low operation speeds (10 to 150 ppm), the temperature of the heating element 5 is ioo°C. When the packaging machine is operating at material change speeds (150 to 250 ppm), the temperature of the heating element 5 is no°C. At normal running speed (250 ppm or above), the temperature of the heating element 5 is 120°C. It is to be appreciated that these temperatures are examples only and may vary dependent on ambient temperature and material type.

Figure 5 illustrates the method steps according to an embodiment of the present invention. The method includes a first step Si which comprises positioning the heating roller 4 in rolling contact with the surface 3 of the sheet of material 2 as the sheet of material 2 is conveyed along the conveyance path such that the sheet of material 2 is heated by the heating roller 4. The method step may also comprise a second step S2 which comprises moving the heating roller 4 between a disengaged position, in which the heating roller 4 is spaced from the surface 3 of the sheet of material 2 as it is conveyed along the conveyance path, and an engaged position, in which the heating roller 4 is in rolling contact with the surface 3 of the sheet of material 2 as it is conveyed along the conveyance path. The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc, other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.