WO1991007867A1

WO1991007867A1 - Sheathing apparatus

Info

Publication number: WO1991007867A1
Application number: PCT/GB1990/001820
Authority: WO
Inventors: David James Cundall
Original assignee: Ag-Bag Corporation
Priority date: 1989-11-24
Filing date: 1990-11-23
Publication date: 1991-06-13
Also published as: GB2244971A; GB2244971B; CA2045626C; GB9115925D0

Abstract

Baled material (4) is fed into a resilient sheath (4) through an open end thereof with at least the open end portion held in a resiliently expanded condition so that after insertion of the material the sheath can contract around the material, so expelling excess air. The sheath is held by a holding device having members (25; 124) movable on cranks between positions in which the sheath can be readily located on the members in its unstressed condition and in which at least the open end of the sheath is enlarged by stretching.

Description

SHEATHING APPARATUS

The present invention relates to a method of an an apparatus for placing material, for example, straw grass, hay or silage, which may, but need not be forme into bales, within a tubular sheath.

There is known from GB 2 136 761 A, a bale sheathing device comprising a mobile sheath-carryin structure arranged to support and hold open an axiall closed-up portion of a tubular sheath in a manne enabling said closed-up portion to be progressivel pulled out rearwardly off the sheath-carryin structure, and bale lifting and guide means carried b the mobile sheath-carrying structure and arranged t lift up a bale to be sheathed and guide it through the closed-up portion of the sheath as the device is advanced relative to the bale, the device being so arranged that after passage through the closed-up portion of the sheath, the bale is put down again whereby, in use of the device, the bale comes to rest within an axially opened-out part of the sheath pulled out off the structure during advance of the device.

It was proposed in GB 2 136 761 A that this device be used to sheath bales within tubular plastic sheaths of greater diameter than the bales. Thus, for example, tubular plastics sheaths of 2m diameter and up to 80m in length were proposed to be used for containing large round bales of up to 1.8 m in diameter.

It has however now been appreciated that the relatively large volume of air necessarily contained within a plastics sheath of this dimensional relationship with the baled material can promote undesired fermentation. Also, the slack portions of the sheath are liable to be snagged and torn. The present invention is thus concerned with the provision of a sheathing method and apparatus by which these disadvantages may be overcome.

The present invention accordingly provides a method of and an apparatus for sheathing material in which the material is fed into a resilient sheath through an open end thereof with at least the open end portion of the sheath held in a resiliently expanded condition so that after insertion of the material the sheath can contract around the material, so expelling excess air. The sheath can thus be held during insertion of the material by a holding device having a first position in which the sheath can be readily located on the device in its unstressed condition. The device can then be operated so as to enlarge at least the open end of the sheath by stretching of the resilient plastics sheet of which it is constructed.

The holding devi_see can comprise a plurality of cranks spaced around the periphery of a support ring, the cranks having mounting portions journalled on the ring about axes parallel to the ring axis and axially offset parallel support portions extending away from the ring in the direction in which the material is to be loaded into the sheath. Initially, the cranks are positioned so that the support portions are all located at their innermost positions. The sheath has a diameter in its relaxed condition which is intermediate between that of the ring and that of the circle on which the crank second portions initially lie, so the sheath can be readily placed on the cranks. Rotation of the cranks on the support ring effects movement of the support portions outwardly to positions adjace the support ring periphery,so this movement stretch the sheath side wall so that the sheath has an open e of a cross-section approximating to that of the suppo ring.

The rotation of the mounting portions of t cranks about their axes can be effected by any suitab common drive mechanism. For example, the cranks may mechanically linked by a linkage acted upon by a hydraulic ram. Alternatively, the mounting portion could be rotated by rotation of an outer ring to whic the cranks are in driven relationship by means of gea teeth on the outer ring and meshing with gear teeth o the mounting portions. In the stretched condition of the sheath, th material to be sheathed, preferably but not necessaril in the form of bales, can enter the stretched sheat through the support ring by appropriate relativ movement of material and the apparatus. The suppor ring can thus be carried by a frame which can b connected to a powered vehicle, for example, a tractor so as to be driven over a field so as to move into th sheath baled material awaiting sheathing.

Any convenient equipment can be used to effec filling of the sheath with the material to be enclosed for example, the bale lifting and guiding mean disclosed in GB 2 136 761 A where the material i available in baled form. Blades or wheels or roller can thus be provided to engage underneath the materia and also to engage its sides if in baled form, so as t guide the material into the sheath. A conveyor fo example a passive belt conveyor can be employed instea or in addition to such guide means.

Preferably the sheath is initially contracte lengthwise, as by being bunched, convoluted or forme with bellows-like folds as taught in GB 2 136 761 A. When feeding in of the material begins, by relative movement of the material and the sheath and its holding device, the sheath is then extended lengthwise off the holding device by the incoming material so as to contract resiliently around it. The sheath can be a blown film of plastics material capable of being stretched in respect of its circumference by about 25%. Because of its plastics memory, the sheath will shrink back to about 5% extension within 30 minutes of release with a further contraction over the next 24 hours.

The present invention thus provides for the enclosure in a plastics sheath of straw, hay or silage material, for example, in a convenient and efficient way, by use of simple apparatus. The material is compactly ensheathed without undue free air space within the sheath, so that undesired fermentation is restricted or eliminated. The material is sheathed in such a way that the sheath is resistant to being split or torn, and because of the tight fit of the material within the sheath, a minimal quantity of sheathing material is employed.

The invention is further described below, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a front view of a first apparatus in accordance with the invention;

Figure 2 is a sectional side view of the apparatus of Figure 1 in use and with parts omitted; Figure 3 is a plan view of the apparatus of Figures 1 and 2 again shown in use and with parts omitted;

Figures 4 & 5 are respectively front and side views of a second apparatus in accordance with the invention; and Figure 6 is a fragmentary perspective view of a modification of the apparatus of Figures 4 and 5.

The illustrated apparatus 1 is particularly suitable for enclosing large generally cylindrical bales of for example 1.22 metres (48 inches) in diameter in a tubular sheath of resiliently stretchable plastics material having a rather smaller unstretched diameter for example 1.14 metres (45 inches) in its relaxed or unstretched condition. The apparatus 1 comprises a movable sheath support structure mounted on two ground engaging skids 3. The support ring structure includes a rigid metal ring 5 defining an entry mouth 6 large enough to allow the passage therethrough of the large round bales of about 1.22 metres in diameter with limited but adequate clearance. The ring 5 mounts around its periphery sheath holding or support means, described in detail below, capable of holding at least an open end portion of a tubular plastics sheath 4 of resiliently stretchable material with the open end portion stretched open from a relaxed or unstressed condition, so as to correspond at least approximately in cross- section to that of the mouth 6. The sheath 4 is held on the holding or support means in a condition in which it is not only stretched open but in which it is also axially closed up or contracted as by being concertinered or otherwise provided with peripheral folds so as to considerably shorten its axial length, as indicated in Figure 2. Initially, the shortened axial length can be little more than the length of the support means even with a sheath of some 61 m. (200 feet) length.

Each skid 3 is rigidly connected to the ring 5 by means of a respective leg 7 and strut 8. The skids 3 are arranged to support the support structure at a height off the ground sufficient to ensure that the gap beneath the bottom of the structure and the ground is large enough to prevent the stretched, bunched-up, sheath on the structure, dragging on the ground upon advance of the apparatus on the skids. In practice, the gap between the support structure and ground is of the order of 0.18 m (7 inches).

The apparatus 1 includes means arranged to lift a bale B off the ground and to guide it into the mouth 6 of the support structure. These comprise a pair of blades 10 which project downwardly from the ring 5 and forwardly in the intended direction of advance A of the apparatus. The shape and disposition of the blades 10 is such that upon advance of the apparatus towards a bale B, the blades engage beneath and on respective sides of the bale B and progressively lift it into the mouth. A roller 11 carried by the ring 5 at the bottom of the mouth facilitates the transfer of the bale B from the blades 10 into the interior of the support structure.

To enable the apparatus to be towed by a tractor 1 3 wh i l e l e a v i n g t h e f r ont o f t h e a p p a r a t u s unobstructed , an of f set towing rig 1 4 is provided. This rig 1 4 includes a transverse bar 1 5 which is rigidly connected to the ring 5 and, in use, can be coupled to the tractor in a manner such that the bar 1 5 remains orientated transversely of the tractor centre line. In an alternative arrangement, the bar 1 5 may extend forwardly as well as transversely ( for example , at an angle of 45° ) .

Turning now to the sheath holding or support means carried by the ring 5, this comprises a suitable number of cranks 20, for example six, distributed uniformly around the periphery of the ring. Each crank 20 comprises a rod-like mounting portion 21 extending parallel to the axis of the ring 5 and journalled in a fitting 22 secured to the outer edge of the ring. An intermediate portion 24 extends in the release or loading position illustrated in Figure 1 generally radially inwardly of the ring 5, on its downstream side (having regard to the direction indicated by the arrow A). From the free inner end of the intermediate portion 24, a rod-like support portion 25 extends parallel to the first or mounting portion for a length sufficient to support the plastics sheath. The intermediate portions 24 of the cranks extend outwardly from the mounting portions 21 and are pivotally connected to links 26 which extend to like pivotal connections with adjacent cranks 20. The links 26 thus form a series of links interconnecting all the cranks 20, which series may extend entirely around the ring 5.

Movement of the cranks 20 is effected by means shown in Figure 1 but omitted from Figures 2 and 3 for the sake of clarity. One of the cranks 20A has an intermediate portion 24 extending outwardly beyond the pivotal connection with the links 26 to a pivotal connection with the piston rod 27 of an hydraulic ram of which the cylinder 29 is pivotally connected to the towing rig 14. By extending and contracting the hydraulic ram, the cranks 20 can be pivoted about the axes of the mounting portions 21 on the support ring 5 so as to alter the position radially of the support portions 25, this movement being conveyed from the crank 20A to the other cranks by the links 26, so that all the cranks move uniformly together in the same direction.

Operation of the apparatus is described below. Initially , the hydrau l i c ram 27 , 2 9 i s moved , i f necessary , to its contracted position, corresponding to the radially innermost position of the support portions 25 of the cranks 20. The tubular sheath 4, in an axially contracted condition is then placed on the support portions 25 and the rear end of the sheath is closed to form a sealed end 30 at the free ends of the support positions. The unstressed diameter of the sheath, typically 1.14 metres (45 inches), is such that it can be received on the support portions 25 in this position without stretching, so that the preferred axial contraction can be conveniently ensured. As much as 80 m of sheath can normally be accommodated on the support portions 25.

The hydraulic ram is then extended so as to move the support portions 25 outwardly. This outward movement stretches the wall of the sheath 4, so as to increase its peripheral extent. The final outward position of the support portions 25, shown in Figure 2, corresponds at least approximately to a stretched condition of the sheath wall in which it forms, in effect, a continuation of the support ring 5. A sheath having an unstressed diameter of 1.14 metres can be expanded to a diameter of about 1.52 metres (60 inches) to accommodate a bale of 1.22 metres.

In order to sheath a row of large round bales B, the apparatus is aligned with one end of the row. The tractor 13 can then be advanced in the direction of arrow A to move the blades 10 beneath the first bale B, causing the latter to be lifted up through the mouth of the ring 5 and into the space between the crank support portions and then into the interior of the stretched and axially contracted sheath.

As the tractor 13 continues its advance, the blades 10 engage beneath the second bale B and raise this bale up towards the ring mouth, the first bale B being pushed by the second along the crank support portions. With the subsequent passage of the third bale B up the blades 10, the first bale B is pushed outwardly beyond the ends of the support portions. The bale B then engages the sealed end of the sheath 4 and causes some of the sheath to be drawn off the crank support portions. The portion of the sheath 4 drawn off in this way is pulled out to its full axial extent and also resiliently contracts around the bale so as to engage and slightly compress it. It is of course the bunched-up sheath which moves about the bale B rather than vice versa and the first bale is deposited back on the ground within the sheath when it has emerged from between the support portions.

This first bale B thereafter serves as an anchor for the sheath 4 so that as the apparatus moves away from the first bale, a corresponding length of sheath is pulled off to contract around the second, third and subsequent bales as these in turn pass through the space between the crank support portions to be deposited back on the ground, tightly enclosed by the sheath 4.

All the bales B of the row are thus sheathed in a single continuous operation. The last bale in a row, or an isolated bale, is moved through the apparatus manually or in some other way, as there is no following bale to "push" this bale right through it.

In Figures 4-6 the reference signs used in Figures 1 -3 are used to indicate parts of the second apparatus 100 of the invention which are identical or functionally similar to parts of the first apparatus. Except as described below, the second apparatus 100 corresponds in function and configuration to the apparatus 1.

The second apparatus 100 again has a support structure including a ring 5 supported at one side only by a wheel 103 carried by an arm 107 projecting laterally from the lower region of the ring.

To guide the bales B into a sheath stretched onto the sheath holding means of the apparatus 100, a conveyor 110 extends from a position somewhat forward of the ring 5 to a rear position approximating to the rear end of the sheath holding means. The conveyor has a belt 111 which moves on rollers of which the ends are journalled in spaced parallel bearings 112 extending axially from the base of the ring 5. To provide lateral support for the bales B, frame members 118 extend forwardly from the ring 5 and are bent downwardly and inwardly to terminate just short of the forward roller of the conveyor 110. The apparatus 100 is also arranged to be advanced by a tractor to which it can be connected by means of the offset towing ring 14. The apparatus is then additionally supported by the wheel 103. When disconnected from the tractor, as shown in Figure 4, the apparatus rests on the wheel, the frame member 115 and the rear ends of the beams 112.

The sheath holding means of the apparatus 100 again comprises cranks operating similarly to the cranks 20 but comprising arms having inclined inner and outer portions 121 and 122 pivoted to the ring 5 at the join of these portions. A rod-like sheath mounting portion 124 extends axially rearwardly from the inner end of each inner portion 121 and a link 125 is pivotably connected to the outer end of the outer portion 122. The link 125 extends to a pivotal connection to the next outer portion 122 in the direction away from the hydraulic ram, the piston rod 27 of which is pivotably connected to the outer end of the adjacent centre portion 122A. To prevent the sheath end from being stretched in a straight line between the two lowermost portions 124 above the conveyor, a fixed shaft 127 extends parallel to these portions on each side of the conveyor and is received within the sheath together with the portions 124. The sheath holding means of the apparatus 100 can include means for individual adjustment of the relative positions of the mounting portions 124 and/or adjustment of all the portions 124 to accommodate sheaths of different diameter. Both such adjustments can be provided for by making the lengths of the links 25 selectively variable. Conveniently, as shown at the left-hand side of Figure 4, each link can comprise two tubular end portions 128 having tapped adjacent end portions connected by an intermediate portion 129 threaded so that the portions 128 are drawn together or spaced apart by rotation of the threaded portion.

In the modification shown in Figure 6, each of the frame members 115 mounts two spaced rollers 130 about rotational axes which are parallel and inclined downwards and inwardly so that the four rollers constitute a roller conveyance of V-shaped cross- section extending rearwardly from just forwardly of the conveyor 110 to just forwardly of the ring 5.

Various modifications to the apparatus described are, of course, possible. For example, the apparatus can be provided with a power drive for the input rollers or conveyor, or can be made self-propelled rather than tractor-drawn. Different forms of the holding device for the sheath can be employed.

Claims

1. A method of enclosing baled material within a resilient tubular sheath comprising the steps of stretching the sheath so as to have at least an open end portion of greater cross-sectional area than in the relaxed condition of the sheath, relatively moving the sheath and the material to effect entry of the material into the sheath, and allowing the sheath to resiliently contract around the material received therein.

2. A method as claimed in claim 1 wherein the sheath is held in the stretched open condition by holding means from which the sheath is released to contract around the material by the relative movement of the material and the sheath.

3. A method as claimed in claim 2 wherein the sheath is held on the holding means in an axially contracted condition so as to be progressively axially extended by movement of the portion thereof containing the material from the holding means.

4. An apparatus for enclosing baled material within a resilient sheath comprising a holding device for holding the sheath with at least an open ended portion thereof stretched to provide an enlarged open end of greater cross-sectional area than in the relaxed position thereof, and means for relatively moving the material and the holding means so that the material enters the sheath through the enlarged open end thereof, whereby the sheath can subsequently resiliently contract around the material therewithin.

5. An apparatus as claimed in claim 4 wherein the holding device is such as to permit removal therefrom of the stretched sheath as .the material enters the sheath, to thereby effect the contraction of the sheath around the material.

6. An apparatus as claimed in claim 5 wherein the holding device is arranged to hold the sheath in an axially contracted condition from which the sheath is progressively axially extended as it leaves the holding device.

7. An apparatus as claimed in claim 4, 5 or 6 comprising roller or conveyor means for assisting entry of the material into the sheath.

8. An apparatus as claimed in claim 7 having a power drive for the roller or conveyor means.

9. An apparatus as claimed in claim 4, 5, 6, 7 or 8 comprising mounting means mounting the holding device with the open end of the sheath in substantially upright position, and means for moving the holding device over a surface on which the material rests to cause entry of the material into the sheath.

10. An apparatus as claimed in claim 4, 5, 6 or 9 wherein the holding device comprises a plurality of elongate members extending substantially in ring formation in the direction of relative movement, and means for moving the members between an inner position in which the sheath can readily be placed on the members and an outer position in which a sheath so placed on the members is stretched to provide the enlarged open end.

11. An apparatus as claimed in claim 10 wherein the holding device comprises a ring member having spaced around it a plurality of arms pivoted on axes parallel to the ring member axis, wherein each of the elongate members extends axially from a respective one of the arms at an end thereof inwardly of the ring member, and wherein the arms are connected together outwardly of the ring members by links whereby the elongate members can be moved together between the inner and outer positions thereof.

12. An apparatus as claimed in claim 11 comprising a hydraulic or pneumatic jack connected to the linkage to effect the movements between the inner and outer positions.

13. An apparatus as claimed in claim 11 or 12 comprising a frame mounting the ring member in a substantially upright position and means on the frame for connection thereto of a powered vehicle moving the device over ground on which the material rests in baled form.

14. An apparatus as claimed in claim 13 comprising a passive belt conveyor at the lower region of the ring member to assist entry of the material into the sheath.

15. An apparatus as claimed in claim 12 or 13 comprising fixed guide means at the lower region of the ring member providing lateral guidance for material entering the sheath.

16. An apparatus as claimed in any one of claims 10-15 including means for adjusting the inner positions of the elongate members individually and/or collectively.