Apparatus and methods for wrapping cylindrical objects

Abstract

The invention provides an apparatus for wrapping a film around a cylindrical object, the apparatus comprising a wrapping table supported by a base frame. The wrapping table is configured to support the cylindrical object and has a plurality of support rollers which rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object. At least one wrapping arm is configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table to wrap the film around the cylindrical object in partially overlapping layers. An inclining mechanism is operable to move the wrapping table between a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal, and a second condition in which the axes are inclined at a roller angle with respect to the base frame.

Description

[0001] APPARATUS AND METHODS FOR WRAPPING CYLINDRICAL OBJECTS

[0002] The present invention relates to apparatus and methods for wrapping cylindrical objects such as bales of consolidated material. Aspects and embodiments of the invention relate particularly to apparatus and methods for use in wrapping cylindrical objects with a film.

[0003] Background to the invention

[0004] In the agricultural industry, it is common to compact materials into consolidated bales for handling, transport, storage and reuse. Example materials include grass, maize, sugar beet pulp and other plant matter. Bales of wood chips, wood shavings, wood wool, organic waste and other biomass are also formed and used in other industries. It is common to wrap the bales of material with a plastic film or foil, either using combination machines designed to form and fully wrap a bale, or using machines designed for wrapping pre-formed bales. Preformed cylindrical bales might be partially wrapped in the baling machine by providing a net or a plastic film that covers the entire curved side surface of the bale. In such cases it is still necessary to fully wrap the bale in order to seal the end planes of the bale and increase the coverage over the curved surface for protection and containment.

[0005] When wrapping pre-formed bales, a wrapping machine is required to pick up the bale from the ground, transfer it to a wrapping location on the machine, and return the wrapped bale to the ground. This must be achieved with minimal loosening or loss of material, and minimal damage to the bale and the wrapping film. Bales formed from some materials are more prone to damage than others. For example, bales formed from grass or other matter that can be compacted into a cohesive mass are relatively stable, whereas bales formed from dry and small material particles (e.g. wood chips) or heavy and slippery material particles (e,g. sugar beet pulp) are of relatively low stability, and required careful handling, particularly before they are fully wrapped.

[0006] Conventional wrapping devices have a supportive surface underneath the bale, often referred to as a wrapping table, and means of achieving relative rotation between the bale and at least one film roll. The relative rotation could either be due to a stationary bale and a moving film roll, or the bale may be rotated with respect to a static film roll. Typically, a cylindrical bale is also slowly turned around its own axis on the wrapping table at a speed adapted to the rotational velocity of the film roll, to ensure a certain overlap of the foil from one turn to the next. In conventional wrapping methods, every layer of film will wrap the centre of the bales side surfaces, but only a small portion of the edges of said side surfaces. A consequence is that much more plastic film foil will be applied in the centre of the sides than on the edges. The number of layers is essential for the preservation of the bales’ material, where more layers give a better preservation. For example, for bales with diameter 1150mm and width 1200mm and standard width of the plastic film of 750mm, in order to obtain a foil wrapped bale with at least six layers of foil at every point of the bale, the centre of the sides of the bale is provided with approximately 27 layers of foil. This means that an excessive amount of plastic foil, and number of rotations of the film roll is necessary to achieve the required coverage. If the bale is covered as the example above, with 27 layers in the central cluster, and 6 at the edges, the edges will be the point of leakage and thus the limiting factor for the quality of the bales’ preservation.

[0007] WO 2023 / 106929 describes a bale wrapping apparatus that improves the efficiency of bale wrapping by applying the film with an inclination angle between the wrapper arm and the wrapping table, where the wrapping table is shorter than a typical bale length so that an end of the bale is unsupported.

[0008] WO 2015 / 185732 describes a bale wrapping machine that has an inclined bale supporting arrangement to help prevent a bale from drifting off from the end of the rollers and to compensate for offset wrapping that occurs when the bale is rotated at increased speeds.

[0009] Summary of the invention

[0010] There is generally a need to develop bale wrapping and / or handling machines to enable effective implementation of efficient wrapping methods, in particular those using inclined wrapping tables.

[0011] It is amongst the aims and objects of aspects the invention to provide a bale wrapping machine and / or method of use which enables efficient bale wrapping in terms of film consumed and / or wrapping time. It is a further aim and object of aspects of the invention to provide a bale wrapping machine that reduces damage to bales and / or loss or loosening of materials. It is a further aim and objective of aspects of the invention to enable implementation of efficient wrapping methods in a machine package that is compact to facilitate transport (e.g. on public roadways).

[0012] [C]

[0013] According to a first aspect of the invention, there is provided an apparatus for wrapping a film around a cylindrical object, the apparatus comprising: a wrapping table supported by a base frame, the wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein the wrapping table is operable to move between a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal, and a second condition in which the longitudinal axes of the plurality of support rollers are inclined at a roller angle with respect to the horizontal; wherein the apparatus further comprises an inclining mechanism operable to move the wrapping table between the first and second positions, wherein the inclining mechanism comprises an actuator positioned between a part of the base frame and a part of the wrapping table.

[0014] The actuator may be positioned part way along the length of the wrapping table (as determined by the length of the support rollers. The actuator may be positioned closer to a raised end of the wrapping table than a low end of the wrapping table when the table is in the second condition.

[0015] The actuator may comprise a hydraulic actuator. Alternatively, or in addition, the actuator may comprise an electro-mechanical actuator.

[0016] The actuator may be a linear actuator, and may comprise a hydraulic cylinder operable to move between an extended and a retracted condition. Alternatively, tor in addition, the actuator may comprise a rotary actuator. The actuator may be oriented to extend substantially vertically from the base frame.

[0017] At least one of the plurality of support rollers may have a length less than an axial length of the cylindrical object. Having one end of the bale unsupported enables wrapping of a bale around and under a lower edge between the cylindrical side surface and an end plane surface of the bale.

[0018] The apparatus may comprise a supplementary bale support assembly. The supplementary bale support assembly may comprise at least one supplementary surface. The supplementary surface is preferably a surface of a roller, but could be another low friction surface.

[0019] The at least one supplementary surface may support a part of the cylindrical object when the wrapping table is in the first position. The at least one supplementary surface may be retracted from the wrapping table when the wrapping table is in the second position.

[0020] The at least one supplementary surface may comprise at least one, preferably two or more, supplementary support rollers. The supplementary support roller or rollers may extend from a side of the apparatus in a direction opposing the extension of the wrapping table, which is also the raised end of the wrapping table. The supplementary support roller or rollers may be horizontally oriented, and / or may support a part of the cylindrical object when the wrapping table is in the first position.

[0021] The at least one supplementary surface may comprise at least one end roller. The end roller may have a roller axis that is oriented in a substantially vertical plane. The end roller may vertically overlap an end plane of a bale when the apparatus is in a first position.

[0022] The supplementary bale support assembly may comprise a frame, and the at least one supplementary surface may be mounted to the frame. The assembly may comprise one or more retractable wing members, and the supplementary surface(s) may be mounted on a respective wing member. The retractable wing members may be operable, e.g. by actuation, to move between an extended position in which the surface(s) provide support to the cylindrical object (which may be the first position of the apparatus), and a retracted condition in which the surface(s) are clear of the object (which may be the second position of the apparatus). The apparatus may comprise a pair of supplementary support rollers mounted to respective retractable wing members. The apparatus may comprise a pair of end rollers mounted to the frame. The pair of supplementary support rollers and the pair of end rollers may be mechanically linked so that retraction and extension of the supplementary support rollers and the pair of end rollers may be effected by a single actuator.

[0023] The wrapping table may be configured to be pivoted about a horizontal transverse axis between at least two positions. The at least two positions may comprise two of a bale receiving position in which the wrapping table is tipped towards the loading assembly; a bale wrapping position in which the wrapping table is substantially symmetrical about a vertical axis; and a bale ejecting position in which the wrapping table is tipped away from the loading assembly.

[0024] [F]

[0025] According to a second aspect of the invention, there is provided method of wrapping a film around a cylindrical object using an apparatus comprising: a wrapping table supported by a base frame, the wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein the method comprises: supporting the cylindrical object on the wrapping table with the wrapping table in a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal; operating an inclining mechanism of the apparatus to move the wrapping table to a second position in which the longitudinal axes of the plurality of support rollers are inclined at a roller angle with respect to the horizontal; and wrapping a film around the cylindrical object. The method may comprise wrapping the film around the cylindrical object when the wrapping table is in the first position, prior to moving the wrapping table to the second position.

[0026] The method may comprise moving the wrapping table from the second position to the first position. The method may comprise cutting a film with the wrapping table in the first position. The method may comprise unloading the wrapped cylindrical object from the wrapping table in its first position.

[0027] Features of the second aspect of the invention may combined with the first aspect of the invention, and embodiments of the second aspect of the invention may comprise preferred or optional features of the first aspect of the invention.

[0028] [El

[0029] According to a third aspect of the invention, there is provided an apparatus for wrapping a film around a cylindrical object, the apparatus comprising: a base frame; a wrapping table supported by the base frame, the wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein at least one of the plurality of support rollers is has a length less than an axial length of the cylindrical object, and wherein the apparatus comprises at least one supplementary roller which supports a part of the cylindrical object that is unsupported by the plurality of support rollers.

[0030] The wrapping table may be operable to move between a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal, and a second condition in which the longitudinal axes of the plurality of support rollers are inclined at a roller angle with respect to the horizontal. The apparatus may comprise an inclining mechanism operable to move the wrapping table between the first and second positions. The at least one supplementary roller may support a part of the cylindrical object when the wrapping table is in the first position. The at least one supplementary roller may be retracted from the wrapping table when the wrapping table is in the second position.

[0031] The at least one supplementary roller may be a part of a supplementary bale support assembly.

[0032] Features of the third aspect of the invention may combined with the first or second aspects of the invention, and embodiments of the third aspect of the invention may comprise preferred or optional features of the first or second aspect of the invention.

[0033] [D]

[0034] According to a fourth aspect of the invention, there is provided an apparatus for wrapping a film around a cylindrical object, the apparatus comprising: a wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm with respect to the wrapping table about a rotation axis, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein the at least one wrapping arm is supported above the wrapping table by a support structure; and wherein the support structure is adjustable to enable the rotation axis of the at least one wrapping arm to be changed.

[0035] The support structure may comprise an upper structure and a lower structure, wherein the orientation of the upper structure is adjustable with respect to the lower structure to enable the rotation axis of the at least one wrapping arm to be changed. The orientation of the upper structure may be adjustable by inclining the upper structure with respect to the lower structure, which may be by pivoting the upper structure with respect to the lower structure.

[0036] The lower structure may comprise a column, which may extend substantially vertically from the base frame. The upper structure may comprise a horizontally extending beam joined to the lower structure. An upper column may join the beam to the column, or the beam may be coupled directly to the column. The horizontal beam may be oriented in a plane that is approximately perpendicular to the column, although this is not essential as long as the beam extends in a horizontal dimension away from the column.

[0037] The lower structure and the upper structure may be joined together by a pinned coupling, and the pinned coupling may enable the upper structure to pivot with respect to the lower structure. The apparatus may comprise an actuator which acts on the upper and lower structures to adjust the position of the upper structure with respect to the lower structure. The actuator may act across the pinned coupling, and may be attached to the upper structure and the lower structure. The actuator may be a hydraulic actuator. The actuator may be a linear actuator. The actuator may be a hydraulic cylinder which may extend across the pinned joint, and which may be tied to each of the upper and lower structure at respective ends.

[0038] Where the lower structure comprises an upper column, the upper column may be operable to be inclined with respect to the lower structure under control of a control system for the actuator.

[0039] The longitudinal axes of the rollers of the wrapping table may be inclined with respect to the base frame. Alternatively, the longitudinal axes of the rollers of the wrapping table may be parallel to the base frame.

[0040] The wrapping arm may be configured such that a longitudinal axis of a film to wrapped is oriented at an angle in the range of around 20 to 35 degrees to a longitudinal axis of the bale rollers.

[0041] The wrapping arm may be configured such that a centre line of a film to wrapped passes a bale centre point with a maximum offset or deviation from the centre point of 10% of the bale diameter, and preferably 5% of the bale diameter.

[0042] The wrapping arm may be configured such that a film is wrapped over at least one of the edges of the bale between the cylindrical surface and the circular ends. Features of the fourth aspect of the invention may combined with the first to third aspects of the invention, and embodiments of the fourth aspect of the invention may comprise preferred or optional features of the first to third aspects of the invention.

[0043] According to a fifth aspect of the invention, there is provided a method of configuring the apparatus of the fourth aspect of the invention, the method comprising: adjusting the support structure to change the rotation axis of the at least one wrapping arm to achieve a desired wrapping geometry for a selected bale size.

[0044] Features of the fifth aspect of the invention may combined with the first to fourth aspects of the invention, and embodiments of the fifth aspect of the invention may comprise preferred or optional features of the first to fourth aspects of the invention.

[0045] Brief description of the drawings

[0046] There will now be described, by way of example only, various embodiments of the invention with reference to the drawings, of which:

[0047] Figure 1 is a front view of a bale wrapping machine according to an embodiment of the invention, loaded with a bale;

[0048] Figures 2A and 2B are simplified schematic side and front views of a wrapping table of the bale wrapping machine of Figure 1 in a horizontal position, having certain parts removed to improve clarity;

[0049] Figures 3A and 3B are simplified schematic side and front views of a wrapping table of the bale wrapping machine of Figure 1 in an inclined position, having certain parts removed to improve clarity;

[0050] Figure 4 is a flow diagram schematically showing a dual wrapping operation according to an embodiment of the invention;

[0051] Figure 5 is a simplified schematic side view of the bale wrapping machine of Figure 1 in a bale receiving position; Figure 6 is a simplified schematic side view of the bale wrapping machine of Figure 1 in a bale wrapping position;

[0052] Figure 7 is a simplified schematic side view of the bale wrapping machine of Figure 1 in a bale ejection position;

[0053] Figures 8A to 8C are simplified schematic isometric, side and front views respectively of a wrapping table and supplementary bale support assembly according to an embodiment of the invention, in a horizontal position;

[0054] Figures 9A to 9C are simplified schematic isometric, side and front views respectively of the wrapping table and supplementary bale support assembly of Figures 8A to 8C, in an inclined position;

[0055] Figure 10 is a schematic representation of a bale wrapping arm and bale geometry according to wrapping methods used in embodiments of the invention;

[0056] Figure 11 is an enlarged view of an adjustment mechanism of the bale wrapping machine of Figure 1 ;

[0057] Figure 12 is a front view of the bale wrapping machine of Figure 1 , loaded with a bale of different dimensions; and

[0058] Figure 13 is a block diagram schematically showing the functional components of a control system in an embodiment of the invention.

[0059] Detailed description of preferred embodiments

[0060] Embodiments of the invention are described in the context of the handling and wrapping of bales of consolidated material. .Example materials include, but are not limited to, grass, maize, sugar beet pulp and other plant matter, wood chips, wood shavings, wood wool, organic waste and other biomass. The principles of the invention may also be applied to the handling and / or wrapping of cylindrical objects in general, which may be objects other than bales. Nevertheless, the following example embodiments illustrate the application of the invention to the handling and wrapping bales, in which the invention has particular benefits and advantages.

[0061] Referring firstly to Figure 1 , there is shown a bale wrapping machine 100 loaded with a bale 1. Figure 1 is a front view of the bale wrapping machine 100 and bale 1. The machine 100 is designed to be towed by a vehicle such as a tractor (not shown), and has a base frame or chassis 12, a wrapping table 14 comprising multiple rollers 16, and a bale loading assembly 18. A supplementary bale support assembly 15 is provided on one side of the machine. Two wheels 20a, 20b (together 20) are mounted on the base frame 12, and an extending member 22 of the base frame has a coupling 24 at a forward end. Together, the base frame, wheels and coupling enable towing of the machine 100 by a vehicle in a position that enables the bale loading assembly 18 to be brought into proximity with a preformed cylindrical bale on the ground.

[0062] Also provided on the machine is a bale wrapping assembly 120 comprising a wrapping arm 122 supporting film rolls 124, and a support structure 126 that suspends the wrapping arm 122 above the bale 1.

[0063] The machine 100 is shown in Figure 1 with the loading assembly 18 returned to a lowered position, having previously loaded the bale 1 onto the wrapping table 14 such that the curved cylindrical surface of the bale rests on the wrapping table. Figures 2A to 3B are simplified side and front views of the wrapping table 14 and its rollers 16, which are mounted on a part of the base frame 12 via pin attachments 19. Figures 2A and 2B show the table 14 in a horizontal position, and Figures 3A and 3B show the table 14 in the inclined position as also shown in Figure 1. Some parts are removed from Figures 2A to 3B to improve clarity.

[0064] The wrapping table 14 comprises six support rollers 16a-16f, which have roller axes substantially parallel to the longitudinal axis of a loaded cylindrical bale (and perpendicular to the circular end surfaces of the bale). The six support rollers each define a line of contact for the bale surface, and are positioned to form a concave arrangement of supports that corresponds (at least approximately) to the curvature of the bale surface. The support rollers comprise two inner rollers 16c, 16d, close to the lowest part of the cylindrical bale, that is close to a vertical line passing through the centre of an end plane of the bale 1 . Two outer rollers 16a, 16f are displaced circumferentially from the inner rollers, and contact the bale surface at positions vertically higher on the bale. Intermediate rollers 16b, 16e are each located between a respective inner and outer roller. The rollers enable rotation of the bale about its longitudinal axis during wrapping. One or more of the rollers is driven to rotate about its axis by drive motor 19, which is a hydraulic motor, to cause rotation of the bale during wrapping. A greater or lesser number of rollers may be provided in alternative embodiments.

[0065] As shown most clearly in Figures 1 and 3B, the wrapping table 14 is inclined with respect to the base frame 12. The axes of the rollers 16 are inclined with respect to the horizontal plane of the base frame by an angle of inclination 0i in a transverse direction of the machine. In this regard transverse means in a direction between the two wheels, and generally at right angle to the normal forward direction of the machine in use. Angle 0i may be measured in a vertical plane that is oriented transverse to the machine and parallel to axes of rotation of the wheels. Inclining the wrapping table facilitates retention of a bale on the table. Gravity acts on the bale to retain it towards the “low” side of the table, which is provided with an end roller 17 that prevents further movement. A typical value of angle 01 is 9 degrees, although other angles may be used in alternative embodiments. Inclining the angle of the rollers of the wrapping table also facilitates wrapping a film at an inclined angle with respect to a supported bale, as will be described further below. The wrapping table may be inclined, or the axis of a wrapping arm may be inclined, or a combination of both, in order to achieve the desired film orientation.

[0066] The machine also comprises a bale inclination actuator 26 disposed between the wrapping table 14 and the base frame 12 part-way towards one side of the table. The actuator is a hydraulic cylinder, which is coupled to a hydraulic system (not shown). The cylinder is operable to move between a retracted condition, as shown in Figure 2A, and an extended condition, as shown in Figure 3B. In the retracted condition, the axes of the rollers of the table 14 are horizontal (or otherwise aligned with the plane of the base frame 12) in a transverse direction of the machine. In the extended condition, the actuator 26 supports one side of the table in a raised position, and the axes of the rollers of the table 14 are inclined to the plane of the base frame 12 and the horizontal in a transverse direction of the machine. The table 14 is therefore operable to move between a horizontal orientation, which may for example improve loading of a bale onto the table or ejection of a bale from the table, and an inclined orientation which may be preferable for bale retention and / or a desired wrapping geometry. Operation of the actuator 26 to move the table between horizontal and inclined positions may be automated from a control system of the machine, and / or may be manually controlled by an operator.

[0067] The adjustable wrapping table described above facilitates flexible approaches to bale wrapping and improvements in bale handling. One example is the possibility of a “dual mode” wrapping method, as will be described with reference to Figure 4.

[0068] Figure 4 is a flow diagram depicting steps of a bale wrapping method that may be performed using the machine 100. The method, generally shown at 40, comprises a first step 41 of receiving a bale on to the wrapping table 14, while the bale is in a horizontal position as shown in Figure 2. The horizontal position of the wrapping table facilitates smooth loading of a bale from a horizontally oriented loader. The bale is then partially wrapped in a conventional manner (step 42) while in the horizontal orientation to provide a single layer of film around the bale. When a single layer has been applied, all of the material within the bale is contained, albeit not at the level of integrity required of a fully wrapped bale. The actuator 26 is operated (step 43) to incline the wrapping table 14 with respect to the base frame 12. Optionally, the rotary axis of the bale wrapping arm is also adjusted (step 44) to create the required wrapping geometry (see description of Figures 10 to 12 below).

[0069] When inclined, the bale is wrapped (step 45) with an inclined wrapping geometry, for example as described in WO 2023 / 106929 or as described below, until the required number of layers of film have been wrapped around the bale. Subsequently the actuator is operated (step 46) to lower the table to the horizontal position shown in Figure 2. In this position, cutters (not shown) cut the film (step 47), and the wrapped bale is ejected from the machine (step 48).

[0070] The dual mode wrapping operation described above, consisting of a partial horizontal wrapping phase before a second wrapping phase with inclined wrapping geometry, may be particularly suitable for low stability bales of material that have been consolidated but are prone to disintegration. The horizontal table position facilitates smooth loading of a bale from a conventional loading arm, with low impact forces that might cause loosening or material losses before wrapping. The bale is well supported on the horizontal table with evenly distributed forces across the cylindrical surface of the bale during the initial horizontal wrapping phase. The bale is only moved in the inclined position, in which the forces on the bale are more uneven, and in which greater forces are experienced on a lower end surface of the bale, after a layer of film has been applied. The greater integrity of the partially wrapped bale is better able to withstand the forces without damage. In the inclined position, the bale may be wrapped with inclined wrapping geometry that is efficient in terms of film use and wrapping time.

[0071] The number of film layers applied in each wrapping mode may be preset into a control system. The operator can adjust the numbers of layers manually via a Human Machine Interface of the control system, and optionally store them as presets in the system.

[0072] Figures 5 to 7 are simplified schematic side views of base frame 12, wheels 20, loading assembly 18 and wrapping table 14 of the machine 100 in various positions. The support surface of the wrapping table 14 has a generally concave shape that is defined by the positioning of the rollers 16 on an imaginary circle that corresponds to the bale shape. In Figure 5, the table is tipped in a forward direction about an horizontal axis transverse to the machine towards the loading assembly 18. Tipping the wrapping table 14 forwards in this manner facilitates loading of a bale from the loading assembly 18; the lip to the table created by the forwardmost roller 16d is lowered to facilitate transfer of the bale onto the table. In addition, in this position the lip to the table created by the rearmost roller 16a is raised, which helps prevent unintended rolling of the bale off the back of the table.

[0073] Figure 6 shows the wrapping table 14 in a bale wrapping position. Compared with the bale table position in Figure 5, the table 14 is no longer tipped forwards, and is in a neutral or symmetrical position.

[0074] Figure 7 shows the wrapping table 14 in a bale ejection position. The bale table is tipped backwards sufficiently for a bale (e.g. after wrapping) to be easily ejected from the rear of the table 14 and the machine.

[0075] The above-described fore and aft tipping of the wrapping table around a horizontal transverse axis is achieved by a hydraulic actuation assembly (not shown) within the machine. This functionality provides loading and / or ejection improvements when handling and / or wrapping bales. Figures 8A to 9C are simplified schematic views of the wrapping table 14 and supplementary bale support assembly 15 of the machine 100. Figures 8A to 8C show the components in a horizontal position and Figures 9A to 9C show the components in an inclined position.

[0076] The wrapping table 14 is as described with reference to Figures 1 to 3. The inner pair of rollers 16c, 16d is shorter in length than the length of the bale, and supports around 90% of the bale length. The intermediate rollers 16b, 16e support about 75% of the bale length, and the outer rollers 16a, 16f support around 55% of the bale length. This roller arrangement enables wrapping geometries that promote efficient wrapping, as will be described below, but leave significant proportions of the bale unsupported. While this is acceptable for many bale types, for low stability bales of relatively loosely consolidated material, the reduced support for the bale may result in loosening and / or loss of material from the bale.

[0077] This potential issue is mitigated by the supplementary bale support assembly 15. The assembly 15 is arranged on the base assembly 12 at one side so that it opposes the wrapping table. The assembly 15 comprises a frame in the form of vertical support plate assembly 81 to which are mounted a pair of outer supplementary rollers 82, and a pair of end rollers 84. The support plate assembly 81 is in the form of an inverted A shape. The upper extremities of the plate assembly 81 are each connected to outer wing members 85, and an outer supplementary roller 82 is pivotally mounted to each wing member. The supplementary rollers extend and rotate on axes perpendicular to the plane of the plate assembly 81. The wing members 85 are operable to pivot with respect to the plate assembly 81 , and move the supplementary rollers 82 between a support position shown in Figures 8A to 8C, and a retracted position shown in Figures 9A to 9C. The end rollers 84 are each mounted to the extremities of the plate assembly 81 inboard of the wing members 85. The end rollers have rotation axes in a plane parallel to the plane of the plate assembly. In an operating position, shown in Figures 8A to 8C, the end rollers overlap an end surface of the bale 1 , so that they provide low friction abutment surfaces for the bale, assisting with retaining the bale on the table. The end rollers 84 are pivotally mounted to the plate assembly so that they may be moved in the plane of the plate assembly to a retracted position, shown in Figures 9A to 9C. In this embodiment, the mounts for the end rollers 84 are tied to the wing members 85 so that rotation of a wing member causes rotation of the end roller in the opposite direction, and the supplementary rollers 82 and the end rollers can be retracted and extended together by a single hydraulic actuation mechanism (not shown). When the wrapping table is horizontal, as shown in Figures 8A to 8C, the supplementary support assembly 15 is in a support position. The supplementary rollers 82 are located on the same imaginary circle described by the rollers of the wrapping table 14. The supplementary rollers in this embodiment are coaxial with the outer rollers 16a, 16f, and provide additional support to the bale 1 at the unsupported bale end. This position supports the bale in the area of most need; the outer rollers are the shortest of the rollers and therefore provide the least support to the bale.

[0078] Figures 9A to 9C show the wrapping table 14 in an inclined position ready for wrapping with a film. The supplementary support assembly 15 is in a retracted position, in which the supplementary rollers 82 and the end rollers 84 are retracted and provide clearance for a wrapping film.

[0079] The supplementary bale support assembly 15 mitigates against potential issues of inclined wrapping of low stability bales. The arrangement shown has particular application in the method 40 described with reference to Figure 4. In the horizontal position of the wrapping table, the bale is provided with additional support while a partial wrap of film is applied to the bale. The partially wrapped bale is less prone to loosening and / or loss of material than an unwrapped bale, and can be fully wrapped in an efficient inclined wrapping geometry.

[0080] Figure 10 is a simplified, transparent side view showing an advantageous bale wrapping geometry that achieves efficient use of wrapping film and efficient wrapping time. In the arrangement shown, a bale 101 is supported on a wrapping table 114 consisting of two pairs of support rollers, R1 , R2 (only one roller of each pair is visible in the drawing). The wrapping table and bale 101 are inclined in relation to the base frame 112, and the wrapping arms 122 are inclined in the opposing direction, resulting in an angle 03 between the centre line Bci of the bale and the centre line Fciof the film 123 being wrapped.

[0081] Figure 10 shows a desirable configuration of the machine in which the film is wrapped over at least one of the edges of the bale between the cylindrical surface and the circular ends (in this case edge 103), and the centre line Fciof the film passes at a distance d above the bale centre point Bcp. A deviation from crossing of the foil centre line Fcithrough the bale centre point Bciis acceptable within the scope of the invention but the offset or deviation d preferably does not exceed 10% of the bale diameter and more preferably not more than 5% of the bale diameter. In an optimised configuration of the device, the foil centre line Fci of passes through the bale centre point Bcp, i.e. through the exact centre of the bale, and the film may overlap both edges 103 and 105 between the cylindrical surface and the circular ends. A typical angle 03 for the described wrapping method is in the range of 20 to 35 degrees.

[0082] To facilitate wrapping of the film over a lower edge 105 between the cylindrical surface and the circular ends, the support rollers R1 and R2 have a length less than the bale length. The rollers R1 , which are close to the lowermost part of the bale, have an extension only slightly less than the bale length, leaving about 10% of the bale length unsupported. The second support roller pair R2 is significantly shorter, leaving about 45% of the bale length unsupported. This arrangement of gradually shorter support rollers when moving from the lowermost part of the bale up to higher parts enables the desired manner of bale wrapping. The reduced extension of the support rollers is required to avoid conflict thereof with the foil to be wrapped. It will be appreciated that more than two roller pairs may be provided, and typically there will be 2 or 3 pairs of rollers.

[0083] For a given pair of support rollers positioned at a given angle (p from a vertical line through the centre of the cylindrical object (or a vertical line through the centre of an imaginary circle defined by the rollers), there is an inverse correlation between the angle (p (in degrees) and the relative supported length extension Re(N) of the bale, N being an integer 1 , 2 or 3 indicating which pair of support rollers the Re(N) refers to. The larger the angle cp, the shorter the support roller.

[0084] This may be expressed mathematically in an equation constituting a mandatory feature of one specific aspect of the present invention, namely:

[0085] Re(N) < Nemp " k CPN where

[0086] Re(N) is the extension of the support roller in question as a per centage of the length of the cylindrical object, k is a constant decided empirically

[0087] <PN is the angular position of the support roller in degrees from a vertical line through the centre of the cylindrical object (or a vertical line through the imaginary circle defined by the support rollers), Nempis an empiric number found in the development of the present invention. It has been found that Nempis 105 and that k =1 .4.

[0088] It is preferred that the length extensions of the support rolls in practice are chosen within 80 to 100% of the calculated value for Re(N) and more preferred in the region 90 to 95%.

[0089] Figure 11 is an enlarged front view of the machine of Figure 1 , showing a part of the support structure 130 of the wrapping assembly 120. The support structure is designed to facilitate the desired wrapping geometries as described above, including for a typical range of bale sizes likely to be encountered. The support structure 130 has a lower structure and an upper structure. The lower structure comprises a column 130 that extends substantially vertically from the base frame of the machine. The upper structure comprises an upper column 132 and a horizontally extending beam 133. The upper column 132 is attached to an upper end of the column 130, and an upper end of the upper column supports the horizontally extending beam 133 at a first end. The opposing end of the beam 133 supports the wrapping arm 122 and its drive mechanism 136.

[0090] The column 130 and upper column 132 are joined together by a pinned coupling 131 , which enables the upper column 132 to pivot with respect to the column 130. An actuator in the form of a hydraulic cylinder 135 is attached to the column 130 and the upper column 132 across the joint, such that operation of the cylinder can control the relative angle between the respective axes of the column 130 and the upper column 132. Pivoting of the upper column with respect to the vertical rotates the beam and the rotary axis of the wrapping arm, which in turn changes the angle at which the film is applied to the bale. By controlling the angular position of the upper column 132 by the actuator, adjustments can be made to the wrapping geometry, for example to achieve the desired overlaps as described above.

[0091] Figure 12 is a front view of the bale wrapping machine of Figure 1 loaded with a bale 201 of smaller diameter compared with the bale 1. In Figure 13, the rotational axis of the wrapping arm 122 has been adjusted to optimise the inclination between the film (not shown) and the bale by adjustment of the angular position of the upper column 132 to a more vertical position in line with the column 130.

[0092] The adjustment of the support structure for the wrapping arm as described herein provides a simple mechanism for adjustment of wrapping geometry, for example to enable desired wrapping for a range of sizes of cylindrical object. In embodiments of the invention, adjustment can be automated by entering the bale size into a control system for the bale wrapping machine. Alternatively, or in addition, adjustment can be made by an operator.

[0093] It will also be appreciated that the support structure facilitates adjustment of the wrapping arm access to enable the wrapping geometry to be changed from a horizontal wrapping mode and an inclined wrapping mode, as described with reference to Figure 4.

[0094] Figure 13 is a schematic block diagram showing the main functional components of a control system for a bale wrapping machine according to an embodiment of the invention. The control system, generally depicted at 140, comprises a control unit 141 , a sensor system 142, and actuation system 143, and a human machine interface (HMI) 144. The control unit 141 may be a part of a dedicated hardware unit for the machine, located on the machine itself or remotely from the machine. The human machine interface 144 may also be a part of a dedicated hardware unit, or may be in separate hardware communicating with the control unit. The control system 140 may alternatively or in addition be partially implemented in other computer hardware, such as in a module of a general equipment control unit, or as software running on a general computer or mobile computer processing device. The sensor system 142 comprises a number of physical sensors associated with components of the machine, such as an axle position sensor, an inclination sensor, loader (or loading assembly) status sensor, loader (or loading assembly) angle sensor, wrap table (or wrapping table) angle sensor, wrap arm angle sensor, wrap arm position sensors, bale proximity sensor, bale ejector position sensor, film roller sensors. Each sensor is in signal communication with the control unit 141. The control unit 141 operates the actuation system 143 in response to sensor signals and operation commands. The actuation system 143 comprises a plurality of actuators associated with components of the machine. Some or all of the actuators may be implemented as hydraulic actuators, and thus the control unit may control a hydraulic system. Alternatively, or in addition, some or all of the actuators may be electro-mechanical actuators, and thus the control unit may control an electronic system. The system of actuators comprises an axle position actuator, a wrap arm position actuator, a wrap table (or wrapping table) position actuator, a loader (or loading assembly) position actuator, a loader arm (or bale grapple) position actuator, a wrap arm and table drive, cutter actuators, and a bale ejector actuator. In use, the control unit may control the actuation system according to programmed routines and settings, in conjunction with signals received from the sensors. In addition, an operator may select particular settings via the HMI, and / or may manually operate some or all of the actuation system via the HMI.

[0095] In alternative embodiments, the sensor system may comprise additional or alternative sensors for detecting additional or different conditions or statuses of the machine and its components, or may comprise fewer sensors for a simplified control system. Similarly, alternative embodiments may comprise additional or alternative actuators for operating additional or different components of the machine, or may comprise fewer actuators where all components are not present in the machine.

[0096] The invention provides an apparatus for wrapping a film around a cylindrical object, the apparatus comprising a wrapping table supported by a base frame. The wrapping table is configured to support the cylindrical object and has a plurality of support rollers which rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object. At least one wrapping arm is configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table to wrap the film around the cylindrical object in partially overlapping layers. The wrapping table is operable to move between a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal, and a second condition in which the axes are inclined at a roller angle with respect to the base frame. An inclining mechanism moves the wrapping table between the first and second positions, and comprises an actuator positioned between a part of the base frame and a part of the wrapping table.

[0097] In another aspect, the invention provides a bale wrapping apparatus comprising a base frame and a wrapping table supported by the base frame. At least one of the plurality of support rollers is has a length less than an axial length of the cylindrical object, and the apparatus comprises at least one supplementary roller which supports a part of the cylindrical object that is unsupported by the plurality of support rollers.

[0098] In another aspect, the invention provides a bale wrapping apparatus characterised in that at least one wrapping arm is supported above the wrapping table by a support structure; and wherein the support structure is adjustable to enable the rotation axis of the at least one wrapping arm to be changed. The machine and apparatus described comprise features and functions that enable efficient bale wrapping in terms of film consumed and / or wrapping time, while reducing damage to bales and / or loss or loosening of materials in a bale. These objectives are delivered in a machine package that is compact enough to enable transport on public roadways. The invention in its aspects and embodiments are particularly suited to inclined wrapping geometries that have improve efficiency for a wide range of bale materials, including low stability bales of relatively loosely consolidated material, such as dry and small material particles (e.g. wood chips) or heavy and slippery material particles (e,g. sugar beet pulp).

[0099] Various modifications to the above-described embodiments may be made within the scope of the invention, and the invention extends to combinations of features other than those expressly claimed herein.

Claims

22Claims:1 . An apparatus for wrapping a film around a cylindrical object, the apparatus comprising: a wrapping table supported by a base frame, the wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein the wrapping table is operable to move between a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal, and a second condition in which the longitudinal axes of the plurality of support rollers are inclined at a roller angle with respect to the horizontal; wherein the apparatus further comprises an inclining mechanism operable to move the wrapping table between the first and second positions, wherein the inclining mechanism comprises an actuator positioned between a part of the base frame and a part of the wrapping table.

2. The apparatus according to claim 1 , wherein the actuator is positioned part-way along the length of the wrapping table.

3. The apparatus according to claim 1 or claim 2, wherein the actuator is closer to a raised end of the wrapping table than a low end of the wrapping table when the table is in the second condition.

4. The apparatus according to any preceding claim, wherein the actuator comprises a hydraulic actuator or an electro-mechanical actuator.

5. The apparatus according to any preceding claim, wherein the actuator comprises a hydraulic cylinder operable to move between an extended and a retracted condition.

6. The apparatus according to any preceding claim, wherein the actuator is oriented to extend substantially vertically from the base frame.

7. The apparatus according to any preceding claim, wherein at least one of the plurality of support rollers has a length less than an axial length of the cylindrical object.

8. The apparatus according to any preceding claim, wherein the apparatus comprises a supplementary bale support assembly, the supplementary bale support assembly comprising at least one supplementary surface that supports a part of the cylindrical object when the wrapping table is in the first position.

9. The apparatus according to claim 8, wherein the at least one supplementary surface is retracted from the wrapping table when the wrapping table is in the second position.

10. The apparatus according to claim 8 or claim 9, wherein the at least one supplementary surface is a part of at least one supplementary roller.

11. The apparatus according to claim 10, wherein the at least one supplementary roller comprises at least one supplementary support roller.

12. The apparatus according to claim 11 , wherein the at least one supplementary support roller extends from a side of the apparatus adjacent a raised end of the wrapping table.

13. The apparatus according to claim 11 or claim 12, wherein the at least one supplementary support roller is horizontally oriented.

14. The apparatus according to any of claims 11 to 13, wherein the at least one supplementary support roller is coaxial with a support roller of the wrapping table when the wrapping table is in the first position.

15. The apparatus according to any of claims 10 to 14, wherein the at least one supplementary roller comprises at least one end roller having a roller axis that is oriented in a substantially vertical plane, and which vertically overlaps an end plane of a bale when the apparatus is in a first position.

16. The apparatus according to any of claims 8 to 15, wherein the supplementary bale support assembly comprises a frame, and the at least one supplementary surface is mounted to the frame.

17. The apparatus according to any of claims 8 to 16, wherein the supplementary bale support assembly comprises one or more retractable wing members on the frame, and the at least one supplementary surface is mounted on a respective wing member.

18. The apparatus according to claim 17, wherein the retractable wing members are operable to move between an extended position in which the at least one surface provides support to the cylindrical object when the wrapping table is in the first position, and a retracted condition in which the at least one surface is clear of the object when the wrapping table is in the second position.

19. The apparatus according to claim 17 or claim 18, wherein the apparatus comprises a pair of supplementary support rollers mounted to respective retractable wing members and a pair of end rollers mounted to the frame.

20. The apparatus according to claim 19, wherein the pair of supplementary support rollers and the pair of end rollers may be mechanically linked so that retraction and extension of the supplementary support rollers and the pair of end rollers may be effected by a single actuator.

21. A method of wrapping a film around a cylindrical object using an apparatus comprising: a wrapping table supported by a base frame, the wrapping table configured to support the cylindrical object and comprising a plurality of support rollers configured to rotate the cylindrical object on the wrapping table about a longitudinal axis of the cylindrical object; at least one wrapping arm configured to stretch film across the outer surface of the cylindrical object by rotating the at least one wrapping arm or the wrapping table, thereby wrapping the film around the cylindrical object in partially overlapping layers; wherein the method comprises:25 supporting the cylindrical object on the wrapping table with the wrapping table in a first position in which longitudinal axes of the plurality of support rollers are substantially horizontal; operating an inclining mechanism of the apparatus to move the wrapping table to a second position in which the longitudinal axes of the plurality of support rollers are inclined at a roller angle with respect to the horizontal; and wrapping a film around the cylindrical object.

22. The method according to claim 21, comprising wrapping the film around the cylindrical object when the wrapping table is in the first position, prior to moving the wrapping table to the second position.

23. The method according to claim 21 or claim 22, comprising moving the wrapping table from the second position to the first position.

24. The method according to any of claims 21 to 23, comprising cutting a film with the wrapping table in the first position.

25. The method according to any of claims 21 to 24, comprising unloading the wrapped cylindrical object from the wrapping table in its first position.

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