WO1995031892A1

WO1995031892A1 - Bale wrapping apparatus

Info

Publication number: WO1995031892A1
Application number: PCT/GB1995/001169
Authority: WO
Inventors: John Charles Macleod; Andrew Thomas Macleod; Benjamin Tremaine Hatch
Original assignee: John Charles Macleod; Andrew Thomas Macleod; Benjamin Tremaine Hatch
Priority date: 1994-05-23
Filing date: 1995-05-23
Publication date: 1995-11-30
Also published as: AU2532595A; GB9410415D0

Abstract

Apparatus for wrapping rectangular section bales comprises spaced apart substantially parallel bale-supporting rollers which in use cause a bale loaded thereon to rotate about a horizontal axis substantially parallel with the axes of the rollers and means for encircling the bale with a wrapping material and applying the material to the bale, in which the bale-supporting rollers comprise a pair of rollers having a lateral spacing which is less than the minor cross-sectional dimension of a bale to be supported and diameters such that the centre of gravity of a supported bale during rotation thereof is within the vertical planes containing said roller axes.

Description

BALE WRAPPING APPARATUS

This invention relates to bale wrapping apparatus especially for the wrapping of rectangular bales of agricultural material with stretchable self-adhesive plastics film. By "agricultural material" is meant straw, hay fodder, silage and the like.

It has been known -for some time to form agricultural material in large, cylindrical bales -and to wrap such bales for storage purposes with stretchable self-adhesive plastics film, and apparatus for the wrapping of such bales has been developed. For example, EP-A-0234763 describes apparatus for wrapping cylindrical bales, the apparatus including at least two driven horizontal bale- supporting rollers and a crank mechanism for carrying a roll of stretchable self-adhesive film, the roll being moved in a horizontal path around the bale as the bale is rotated by the rollers.

More recently, large rectangular bales have become more common, especially such bales having oblong-shaped faces. Such bales cannot be wrapped on apparatus for wrapping cylindrical bales, because the rollers need to be spaced sufficiently close together to prevent the bale falling through when the bale is positioned vertically with its minor dimension between the rollers, whereby the bale is prone to lateral overbalancing when the bale is positioned at an angle to the vertical, especially since there is a degree of flexure in a large bale which increases the tendency to overbalancing. Apparatus for wrapping rectangular bales has therefore been developed, for example as described in EP-A-0543792, in which two horizontally-disposed drive rollers are each mounted as a roller unit with two auxiliary rollers in a predetermined spaced relationship, typically such that their axes define an "L" configuration in cross section, the "roller units being rotatably prestressed and pivotable about the centre axis of the drive rollers, whereby a rectangular bale can be turned through 360° as the rollers rotate. Such apparatus however tends to be slow in operation and requires the bale to be wrapped to be longitudinally-disposed on the rollers. Additionally, known apparatus requires the use of .relatively narrow, typically 500 mm width, wrapping material, whereas it would be advantageous to be able to use broader material with the possibility of greater overlap between successive turns of the material.

It is an object of the present invention to provide apparatus for wrapping rectangular bales, the apparatus being faster in operation than existing apparatus and being able to accommodate rectangular bales irrespective of whether their length is longitudinally or laterally disposed, in relation to the longitudinal axes of the rollers, and which enables broader wrapping material to be used.

According to one aspect of the present invention, apparatus for wrapping rectangular section bales comprises spaced apart substantially parallel bale- supporting rollers which in use cause a bale loaded thereon to rotate about a horizontal axis substantially parallel with the axes of the rollers and means for encircling the bale with a wrapping material and applying the material to the bale, in which the bale-supporting rollers comprise a pair of rollers having a lateral spacing which is less than the minor cross-sectional dimension of a bale to be supported and diameters such that the centre of gravity of a supported bale during rotation thereof is within the vertical planes containing said roller axes.

In apparatus according to the invention, the diameters of the bale-supporting rollers are larger than the diameters of conventional rollers for use in wrapping cylindrical bales whereby, for a given lateral spacing between the rollers, the effective bale-supporting distance for supporting a non-vertical bale is sufficiently large to ensure that the centre of gravity of the bale is within the said vertical planes and, hence, to prevent the bale from overbalancing laterally externally of one roller or the other.

The bale-supporting distance as a bale is rotated on the rollers is that distance between the points at which the bale is supported on the respective rollers, and may be defined as the length of a tangent from its point of touching one roller in the upper inner-facing quadrant to its point of intersection with the other roller in the upper inner-facing quadrant, such distance being required to be greater than half the major cross-sectional dimension of the supported bale, whereby the bale is always cradled by the rollers and is urged by gravity to adopt a disposition in the valley between the rollers irrespective of its rotational position.

The rollers are preferably laterally adjustable, to allow their spacing to be altered according to the minor cross- sectional dimension of a bale to be wrapped. As indicated, the lateral spacing is required to be less than the said dimension, in order that the bale will be subject to a slight "pinching" effect when in the vertical orientation or, at the least, is in sufficient contact with the rollers when in the vertical orientation that the bale is subject to rotational forces from the rollers. At least one of the rollers may be resiliently biassed towards the other roller, to enhance the gripping effect. The rollers may be provided as replaceable sleeves of different diameters, as one way of providing the or additional dimensional adjustment, or may be rendered expandable and contractable.

In most embodiments"^"of the invention, the rollers will be of circular cross-section but, in the event of a roller of non-circular cross section being used, the diameter will be understood as being double the minimum radius. As an alternative to non-circular rollers, circular rollers could be mounted for rotation about an eccentric axis, to improve the coverage of the bale with the wrapping material.

Optionally, the bale-supporting rollers are arranged for rotation about a vertical axis so that a bale loaded thereon can be rotated about both said horizontal and vertical axes, whereby the bale-encircling means for applying wrapping material to the bale may comprise a stationary wrapping head. In a preferred embodiment, however, the wrapping means comprises at least one wrapping arm which encircles the bale about an axis substantially orthogonal to the horizontal roller axes.

Apparatus according to the invention may include bale- ejection means, for example comprising means to cause the bale to be removed from the valley between the rollers, whereby the bale will be urged by one of the rollers to the outside thereof. Such means may comprise an uplift device between the rollers or a tilting mechanism to the rollers themselves. Preferably, the apparatus includes bale feed and bale removal means, comprising for example tables optionally including conveyors such as belts or rollers which may be driven or pivotable, to allow feed and/or removal under the influence of gravity. The tables may be separate for feed and removal and mounted respectively on each outer side of the bale-supporting rollers, each table surface being preferably tangential to the upper part of the respective roller, to ensure a smooth passage of the unwrapped bale from the feed table to the bale-suporting rollers and of the wrapped bale from the rollers to the removal table. However, common feed and removal means may comprise a raisable and lowerable table optionally including conveyor means and mounted between the bale-supporting rollers, whereby a bale to be wrapped is presented to the table in the raised position, the table is lowered to cause the bale to be cradled by the rollers and, at the end of the wrapping operation, the table is again raised to lift the wrapped bale clear of the rollers for removal. The bale feed and removal means may be demountably attachable to the apparatus or may be pivotably or foldably mounted, for movement between extended in use positions and compact transportation and storage positions.

In apparatus according to the invention, at least one of the bale-supporting rollers is motor-driven, optionally reversibly, and the surface of at least the driven roller may be provided with grip-enhancing means to assist in providing operative engagement with the bale for rotation purposes. Such means may comprise grab teeth or ridges, or a friction coating. A slip arrangement may be incorporated in the driving mechanism or transmission to minimise damage to the wrapping material in the event of any impediment to the free rotation of the bale.

Apparatus according to the invention may be free-standing including integral drive and power means or attachable to a tractor via the standard three-point linkage or draw bar with suitable connections being optionally provided for power take-off purposes, and may be arranged for automated bale handling in terms of delivery and removal of bales.

The invention also provides a method for wrapping a rectangular section bale, the method comprising supporting a bale on substantially parallel rollers and causing the bale to rotate while applying wrapping material to the bale, in which the lateral spacing between the rollers is less than the minor cross- sectional dimension of the bale and the diameter of the rollers is such that the centre of gravity of the bale is within the vertical planes containing the roller axes.

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

Figure 1 illustrates the disposition of the principal elements of bale-wrapping apparatus diagrammatically and

Figure 2 illustrates various instantaneous orientations of a bale during rotation, when supported on the rollers of the apparatus of Figure 1.

Referring firstly to Figure 1 , the apparatus consists essentially of bale-supporting rollers 11 and 12 which are rotably driven by drive means (not shown) in the direction of the arrows about horizontal axes 13, 14. A roller table 15 is provided for feeding rectangular bales to the support rollers and a roller table 16 is for receiving wrapped bales from the support rollers. A pair of cantilevered wrapping arms 17 are attached at their proximal ends to a bush 18 which is mounted for rotation by drive means (not shown) about a central vertical axis 19. The distal ends of the arms 17 each carries a wrapping head 20 which includes a roll of flexible or stretchable self-adhesive plastics wrapping material 21. In use and on rotation of the arms 17 about the axis 19, the wrapping heads 20 encircle or orbit about a bale (not shown) supported on and being rotated by the support rollers 11, 12; at the end of the wrapping operation, an ejection arm 22 is caused to rise vertically between the support rollers 11, 12 to displace the wrapped bale out of the valley between the rollers so that the rotation of the rollers urges the bale onto the roller table 16 for removal and storage. The next succeeding bale to be wrapped is then caused to move from the roller table 15 to be supported by and between the support rollers 11, 12 while the arms 17 and wrapping heads 20 encircle the bale and apply wrapping material from the rolls 21. The roller tables 15 and 16 are hinged to the body of the apparatus at horizontal axes 23, 24, to permit the tables to be extended horizontally, as shown, for use or to be swung upwardly to a stowed position for transportation and storage.

With reference to Figure 2, four instantaneous positions assumed by a bale being rotated by the support rollers 11, 12 of the apparatus of Figure 1 are illustrated. In Figure 2(a), the bale is shown disposed vertically; as shown, the minimum distance between the surfaces of the rollers 11, 12 corresponds with the minor cross-sectional dimension of the bale and the bale cannot, therefore, slip downwards between the rollers. Figures 2(b), (c) and (d) illustrate three non-vertical positions of the bale and, in each case, the bale-supporting distance between the rollers 11, 12 is defined by a tangent from the surface of roller 11 to intersect the surface of roller 12, as shown by the line X in Figure (b), the line Y in Figure (c) and the line Z in Figure (d) . It will be seen that, in Figures (c) and (d), the tangent coincides with the lower surface of the bale. After the position illustrated in Figure 2(d), and on further rotation of the rollers 11, 12, the bale is moved to the right, as shown, whereupon the lower rear corner region 25 assumes a position in the valley between the rollers as the bale moves towards the next vertical orientation, similar to that shown in Figure 2(a) but with the bale inverted. It will be understood that at no time during the total rotation process does the bale assume an unstable condition with respect to the rollers; by contrast, it is at all times stably held between the upper inner quadrants of the support rollers and will not, therefore, topple out. In addition, the bale is automatically correctly aligned with the rollers as it moves off the feed table 15 and into the valley between the rollers, irrespective of its positioning on the feed table.

It has been found that large silage bales having a major cross-sectional dimension of approximately 1.2 m and a minor cross-sectional dimension of approximately 0.6 m can be satisfactorily wrapped on apparatus according to the invention, using rollers of diameter 0.6 m. Prior art rollers, by contrast, have a typical diameter of approximately 25 cm and it has been found that bales having the above dimensions, when attempts have been made to wrap them on prior art rollers, overbalance.

Wrapping material of 700 mm in width may be satisfactorily applied to the bales using the inventive apparatus.

Claims

1. Apparatus for wrapping rectangular section bales, the apparatus comprising spaced apart substantially parallel bale-supporting rollers which in use cause a bale loaded thereon to rotate about a substantially horizontal axis substantially parallel with the axes of the rollers and means for encircling the bale with a wrapping material and applying the material to the bale, in which the bale-supporting rollers comprise a pair of rollers having a lateral spacing which is less than the minor cross-sectional dimension of a bale to be supported and diameters such that the centre of gravity of a supported bale during rotation thereof is within the vertical planes containing said roller axes.

2. Apparatus according to Claim 1, in which the rollers are laterally adjustable towards and away from each other.

3. Apparatus according to Claim 1 or Claim 2, in which at least one of the rollers is resiliently biassed towards the other roller.

4. Apparatus according to any preceding claim, in which the rollers are provided as replaceable sleeves of different diameters, rotatably mountable on fixed spindles.

5. Apparatus according to any of Claims 1 to 3, in which the diameter of the roller is expandable and contractable.

6. Apparatus according to any preceding claim, in which the bale-supporting rollers are arranged for rotation about a vertical axis.

7. Apparatus according to any of Claims 1 to 5, in which the wrapping means comprises one or more wrapping arms which encircle the bale about an axis substantially orthogonal to the horizontal roller axes.

8. Apparatus according to any preceding claim, further including bale-ejection means.

9. Apparatus according to any preceding claim, further including bale feed and bale removal means.

10. Apparatus according to Claim 9, in which the bale feed and removal means comprise respective tables for feed and removal and mounted respectively on each outer side of the bale-supporting rollers, each table surface being tangential to the upper part of the respective roller.

11. Apparatus according to Claim 9, in which the bale feed and removal means are common and comprise a raisable and lowerable table optionally including conveyor means and mounted between the bale-supporting rollers.

12. Apparatus according to any preceding claim, in which at least one of the bale-supporting rollers is motor- driven, optionally reversibly, and a slip arrangement is incorporated in the driving mechanism or transmission.

13. A method for wrapping a rectangular section bale, the method comprising supporting a bale on substantially parallel rollers and causing the bale to rotate while applying wrapping material to the bale, in which the lateral spacing between the rollers is less than the minor cross-sectional dimension of the bale and the diameter of the rollers is such that the centre of gravity of the bale is within the vertical planes containing the roller axes.