A METHOD AND AN APPARATUS FOR PRODUCING A SHEET WRAPPED STRING OF PRESSED BALES OF VEGETABLE MATERIAL

Abstract: For building up a sheet protected string of straw or grass bales it is known to move the bales through a rotating ring (12) carrying one or more supply reels (18) for a sheet web (26). During their passage through the ring the bales should be free-carried for enabling a wrapping of the web at the lower bale region, this so far being achieved by a troublesome carrying at the bale through axial clamping of it. With the present invention use is made of a real support shaped as lower carrier spears (22), which in a free-carried manner project rearwardly from the foremost end of the wrapping area, such that the web can be wrapped underneath these spears and thereafter be withdrawn therefrom axially rearwardly in an obstructed manner. It is then possible, advantageously, to make use of a simple feeding conveyor (16) for moving the bales to the wrapping area, and it is also proposed to use, instead of a rigid wrapping ring (22), a round-going carrier belt for the web reels, this belt being advanceable through straight partial runs between position adjustable guiding rollers (30) for adaptation to bales of different cross-sectional shapes.

Description: A method and an apparatus for producing a sheet wrapped string of pressed bales of vegetable material. The present invention relates to a method and an apparatus for producing a sheet wrapped string of pressed straw bales, i.e. joined bales of vegetable material, particularly of straw, hey or grass, such that these bales can be stored in the free in a protected manner. Theoretically the bales can be wrapped individually, but the wrapping, of course, will be easier and cheaper, if only a sheet tube should be provided about a string of joined bales. Various techniques have been proposed for producing such a wrapping, but to be considered here is particularly the type based on a successive sheet web wrapping about bales that are laid together for forming a continuous string, this string at its forming area being wrapped by a sheet web, which is wrapped up with a screw shaped configuration and with a certain overlapping between consecutive windings, such that the result will be a generally tightly surrounding wrapping by the sheet web. For carrying out the wrapping the bales are succes¬ sively moved trrough a rotating ring body, which carries at its periphery one or more web roll holders, from which the sheet web required for the screw wrapping is delivered. It is already known to use a similar technique for the wrapping of rigid articles, confer e.g. EP-A2-152,960, which are brought through the wrapping area standing on a conveyor, which, in a free-carried manner, extends through this area, such that the web is wrapped about both the articles and the conveyor; the wrapped string of articles is conveyed further on a succeeding conveyor, whereby it is moved out over the free end of the first mentioned conveyor, such that the underside of the string now be covered by the sheet originally wrapped underneath the conveyor. In order to facilitate an easy delivery of this sheet there is arranged, underneath the conveyor, another conveyor, the lower run of which moves in the same direction as the upper run of the upper conveyor, such that the sheet is caused to be discharged in syncronism with the articles. For the wrapping of large and heavy bales this technique is not usable, because the carrying conveyor arrangement in the wrapping area will be so heavy and thick that it will be difficult or impossible to obtain a resulting wrapping with the required degree of tightness of the sheet web, and in particular round bales will be difficult to treat. On this background, in the relevant prior art it has been chosen to let the bales as successively moved through the rotating ring body be held in an entirely free-carried and non-rotatable manner during their passage through the ring in being held axially squeezed between the end of the bale string so far produced and one or more feeding pistons or, respectively, one or more subsequent bales held under such a piston actuated feeding pressure. This gives rise to problems both at the beginning and the end of the building up of the bale string, where there are no counter pressure bales in front of the first bale and behind the last bale, respectively, while also the length extension of the free-carried stretch and therewith the width of the sheet web will be correspondingly limited. In connection with the invention it has been recognized that the bales may very well be simply supported during their passage of the rotating ring, such that the said problems can be avoided. According to the invention the bales can be supported on a rigid carrier plate or on rigid spears projecting from the inlet side of the ring forwardly, fully or.partly through the ring at the lower area thereof, and in a self supported manner to a free end portion; surely the web will then be wrapped down about such lower carrier means, but this is without any adverse effect, when only the dimension of the carrier means in the radial direction of the ring is reasonably small, because the actually wrapped bale may then easily leave the ring area, the wrapped web hereby being drawn off over the free end portion of the carrier means without any resulting occurrance of overlength or slackness of the web. For example, with the use of only a pair of carrier spears the bales will sink down slightly over the spears, with the bale material compressed locally in the carrier area, and hereby the lower sides of the spears will not have to be located outside the natural peripheral contour of the bales, i.e. the web can be effectively wrapped, as tightly as with free-carried bales. When only the forwardly self-carried carrier means are suitably smooth for the sliding off of the bales and the lower wrapping, respectively, it has been found fully sufficient for the throughpassage of the bales that these are pushed through by a moderate pressure, preferably only from a preceding feeding conveyor acting by the feeding pressure against the next following bale. When care is taken that the wrapping apparatus is moved on the ground corresponding to the throughpassage movement og the bales through the rotating ring, a wrapped row of closely juxtaposed bales can be produced without requirements as to any particularly increased pressure for passing the bales through the ring, and hereby it is possible to make use of a considerably simplified feeding system. The wrapping can be carried out effectively on both the first and the last bale without any special precautions with respect to additional support of the bales. The conveying should take place in synchronism with the delivery from the apparatus, preferably by the pressure excerted by a delivery conveyor for delivering the wrapped article string. Preferably, the invention is even used in connection with a treatment setting high requirements to the tightness of the wrapping, viz. a so-called lye treatment of the bales prior to their incorporation in the wrapped bale row. Whether the product is grass silage or lye treated straw for use as fodder, it is important that the wrapping be tight, such that an escape of the lye agent by evaporation can be counteracted, and it is important, therefore, that the simplification achieved by the invention is not achieved at the expense of the tightness of the wrapping. This tightness is even likely to be improved by the avoidance of the said start and stop problems, which may well give rise to leaks if the extra precautions required for securing the tightness are not taken with great care. In connection with the invention there are no special problems in supporting the bales over a relatively great length, i.e. it is possible to operate with a rotating ring member of a relatively large axial dimension. This involves that it is also possible to use a relatively broad sheet web, which, with the required overlapping between the consecutive windings, will result in a noticeably reduced sheet consumption, because there may be fewer windings per length unit of the bales. In the following the invention is described in more detail with reference to the drawing, in which:- Fig. 1 is a schematic perspective view of an apparatus according to the invention, Fig. 2 is a longitudinal sectional view thereof. Fig. 3 is a cross sectional view along the line III-III of Fig. 2, Fig. 4 is a perspective view of a modified embodiment of the wrapping means, Fig. 5 is a front view thereof, and Fig. 6 a corresponding view of the same means in another configuration thereof. The apparatus shown has a lower chassis 2, which is supported by driving wheels 4 in a position slightly downwardly inclined from a feeding conveyor 6 mounted on the chassis 2 to a delivery conveyor 8 likewise mounted on the chassis. The feeding conveyor 6 is provided with entrainment ribs 10 and is driven by a motor not shown. In the space between the two conveyors there is provided a cross mounted ring body 12, which is supported and centered by resting on cross oriented driving wheels connected with the chassis. The ring body consists of two mutually separated rings held together by means of connector rods 16, and at two diametrically opposite areas there is mounted, between these rings, a holder for a web reel 18. The two conveyors 6 and 8 extend almost in line with each other and further inclined towards the ground, such that the delivery conveyor almost reaches the ground at its free end. The ring body 12 is located so as to have its lower part situated spaced underneath the conveying plane of the two conveyors, such that there will be space for a throughpassage of bales without these interfering with the ring body. In accordance with the invention, however, it is desirable to arrange for a direct support of the bales while they pass through the ring body, and to this end there is provided, on a traverse 20 on the chassis next to the delivery end of the feeding conveyor 6, a pair of forwardly protruding carrier spears 22, which are located approximately in or even slightly above the common plane of the conveyors. These spears extend forwardly almost all the way to the delivery conveyor. 8 In operation, the bales are loaded onto the feeding conveyor 6, preferably in being carried on a front loader spear and driven to a position above the free end of the conveyor, where they are lowered onto the conveyor, whereafter the front loader spear is withdrawn from the bale, with the illustrated upstanding portion 24 used as a holding abutment for the bale. Thereafter the bale is advanced on the driven conveyor 6 so as to be fed to the ring body 12. A preceding bale, after its throughpassage of the ring body, has been stopped with its rear side located just adjacent the front side of the ring body. When it is detected, e.g. by means of a suitable sensor equipment, that the front side of the new bale has reached this position, the driving wheels 14 of the ring body 12 are caused to be started. From the beginning, the sheet webs from the reels 18 have been placed against the sides of the first bale, whereafter the next bales have been wrapped in the sheet by the rotation of the ring body. When the new bale is supplied this wrapping will thus be continued, when the ring body is rotated, and during this rotation the operation of the feeding conveyor 6 is maintained. At the same time the driving motor of the front wheel pair 4 is actuated so as to drive the entire apparatus forwardly with the same speed, by which the conveyor 6 moves the bale rearwardly, whereby the result will be that via the delivery conveyor 8 a further, wrapped bale row portion will be deposited on the ground behind the apparatus. In Fig. 3, the sheet web or webs are designated 26. During the rotation of the ring body 12 the webs 26 will be wrapped tightly about the bale, but also down under the spears 22, which will thus be located inside the wrapped bale. However, as these spears end freely towards the rear they will in no way obstruct a rearward retraction of the wrapped bale, which may thus be transferred to the conveyor 8 without obstruction and without disturbance of the wrapping. In connection with the invention it is possible, in an advantageous manner, to use a rather broad ring body, i.e. having a relatively large axial dimension and a correspondingly large width of the webs 26, e.g. in the range 50-150 cm. For the required tightness it is desirable to make use of a noticeable overlapping between the neighboring windings of the web, and when the invention enables the use of a relatively large web width the result may be both a relatively small sheet consumption and, in spite of that, also a safe overlapping, even where considerable jumps in the bale sizes might occur. It should be noted that for the propulsion of the apparatus it is important that this be effected primarily by the rearward displacement of the bales as caused by the the delivery conveyor 8; it is then ensured that the pushed-off bales remain closely juxtaposed in the 'bale sausage' that is left on the ground, irrespectively of such spacings, with wich the bales are fed to the apparatus. The associated tight juxtaposition is important in that the sheet wrapping will then be continuous and not just partly covering the ends of bales supplied with mutual spacing. This involves a saving of sheet material and a more efficient wrapping of the vegetable material, as the bale ends will not be exposed at all. It will be readily understood that the rearward pushing force of the delivery conveyor will be converted into a forward pushing on the entire apparatus, when the pushing off takes place against a row of previously wrapped bales already resting on the ground. For lateral support of the bales placed on the feeding conveyor 6 there may be arranged side bars, not shown, connected with the chassis 2 and located above and outside the edges of this conveyor. The ring body 12, of course, may be supported and stabilized by various wheel engagements in addition to the carrying by the rollers 14. In practice the chassis 2 may be provided with a further, intermediate set of driving wheels 4, as shown in dotted lines in Fig. 1. Thereby the chassis may be designed so that the entire rear conveyor section 8 can be swung into an upright transportation position, such that the apparatus can be transported with a correspondingly reduced length dimension. The important carrier spears 22 may be replaced by a preferably arch-profiled plate portion correspondingly projecting freely rearwardly from the chassis immediately behind the feeding conveyor. It could be remarked that the apparatus will be well suited for a picking up of the laid-out 'bale sausage', when only the first bale in this sausage is lifted onto the foremost conveyor 8. Based on the apparatus here shown and described, some possible modifications thereof could be as follows: When the intermediate driving wheels 4 shown in dotted lines are used, the wheels 4 at the low rear end of the apparatus may be avoided, and the pivotable conveyor 8, which is held by the front chassis 2, should then only be swung down as far as possible for bringing its outer end as close to the ground as possible. This conveyor could be a simple, pure roller conveyor, without any conveyor belt and with relatively thin rollers, whereby at its free end it can reach almost entirely down to the ground, i.e. causing a minimum of influence on the bale sausage when the latter is delivered to the ground. The foremost retraction stop 24 may be avoided if there is used a bale loader of the type having its own means for pushing off the bales from its carrier spears. It has been mentioned that the front driving wheels 4 are motor driven, controlled for synchronous propulstion of the apparatus, but this function may be superfluous and thus be left out for apparatuses which shall only work on relatively flat, even fields. At such surfaces the motor driven feeding conveyor 6, pushing the new bales rearwardly against the front end of the already established bale sausage, will provide the oppositely directed force required for the displacement of the entire apparatus, because the front end of the bale sausage will be fixed relative to the ground. Hereby it is fully ensured that the successive bales will be fully pressed together, such that no vulnerable gaps will occur, in which the web 26 would not be inwardly supported. Otherwise care should be taken that the conveyor 6 be driven by a speed slightly higher than the propulstion speed of the apparatus determined by the wheels 4. On this background it is realistic to let the feeding conveyor 6 operate continuously as long as the apparatus is in use, although it would of course be possible to use sensor means for starting and stopping this conveyor depending of the factual supply of bales. The apparatus may be provided with a system for injection of a treating fluid in the bales as these are supplied to the feeding conveyor 6 or even as they are delivered therefrom. Most suitably the injection can be effected by ijjecting spears through an end surface of the bales, e.g. one or more curved spears to be injected by an inward pivoting from a side area of the conveyor 6, optionally from an area at the front end of the conveyor. The fluid injection should be dosed in dependence of the moisture content of the material, as hereby the consumption of treating fluid can be minimized, but the injection system may well be combined with or supplemented by means for a rapid measurement of the degree of moisture. Moreover, the injection should be dosed in dependence of the bale weight, and particularly with the use of a feeding conveyor 6, on which the bales may rest freely, it is easy to arrange for a weighing system either underneath the upper run of the conveyor belt or underneath an independent, belt carrying chassis. An associated control unit may rapidly calculate the correct dosage according to weight and moisture content, and by a summing up the unit will be able to provide a reasonably precise indication of the total amount of material in the sausage store, which may be of interest also when wrapping crops that should not be fluid treated, e.g. grass. By the wrapping of the bales it is important, already for minimizing the sheet consumption, that the web be wrapped rather tightly. In the system shown in Fig. 3 this is achievable by the web reels 18 being tardily rotatable or by the web from these reels being paid out through clamping rollers, which can be rotated with a suitably high friction or even are driven with a delivery speed corresponding to less than the supply speed of the web to the round bales. Hereby a tight wrapping and a positive stretching of the web will be obtained currently. The conditions, however, may be different if the contour of the bales or for that sake other units to be wrapped deviates from the circular shape, e.g. in case of rectangular bales. In that case the situation may or will arise that the web reel, after having deposited the web along one side of the unit, will be moved over the next side, but here with a highly varying stretching of the web; during the last phase of this m the web will only be stretched slightly, because the web reel will approach the farther corner of the new side by a motion more or less perpendicularly to this side, such that the rolled off web length will practically only be laid against the side by an inward folding about the front corner of the side. On this background Figs. 4-6 show an important alternative to the use of the circular wrapper ring 12. According to Fig. 4 this ring is replaced by a controlled cord or chain guidance of the web reels 18, in that the ends of these reels are held by brackets 30 outstanding from respective cords, belts or chains 32 running over sprocket wheels 34 in such a manner that the reels 18, when one or more of the pairs of wheels 34 are driven, will be moved around along a four-sided path, which, see Fig. 5, is adapted so as to surround a box shaped bale or article 36, optionally, as shown, two such articles piled on each other. Hereby the reeled off web will be uniformly stretched all the time, because the web reel or reels 18 will be moved substantially in parallel with the single bale or article sides. In Fig. 5 it is indicated that on the delivery side of the web reel or reels 18 theremay be provided guiding rollers 38, which serve to retain the delivered web for building up a tensile stress therein and also to produce a longitudinal stretching and, optionally, also a transverse stretching of the paid out web. The pulleys 34 may be arranged in the apparatus in such a manner that they are easy to rearrange between different positions, whereby their location can easily be adapted to the actual size and shape of the handled articles. Thus, it is shown in Fig. 4 that the pulleys 34 may be carried by fork portions 40, which are height adjustable by means of a connected telescopic system 42. Correspondingly, the inwardly protruding length of the fork portions may be adjustable, such that the apparatus, as shown in Fig. 6, may surround more irregular article shapes, shown as round bales piled into a triangular shape, cf. DK-C-159,987. It would be possible to use a resilient or otherwise length variable cord 32, such that it will not necessarily be required to change out the cords if it becomes actual to shift to another configuration of the bales or the articles. Just because it is highly desirable to operate with a well tightened wrapping web it is correspondingly important that the means for supporting the bales in the wrapping area should not be of any large thickness, confer the spears 22 in Fig. 1. Similar spears may be used in connection with Fig. 4, where, however, there is used a thin carrier plate 44 projecting from a thicker support 46, which may be a chute or a conveyor. The disclosed embodiments are particularly well suited for the handling of vegetable bales, but it will be appreciated that the systems may also handle other articles, which will be particularly relevant for the system according to Figs. 4-6.

Claims: C L A I M S : 1. A method of producing a sheet wrapped string of pressed bales of vegetable material, whereby the bales are successively passed through a wrapping area, in which means for carrying one or more supply reels of a sheet web are moved about each added bale for wrapping the latter in continuation of the preceding wrapping of the preceding added bale, the newly added bale being held axially against the preceding bale and the wrapping means being moved for progressively wrapping the bale, and the bale during its passage through the wrapping area being carried in such a manner that the web reel or reels are freely movable in the cross direction of the string underneath the underside of the bale, characterized in that the bales during their passage of the wrapping area are held carried on a lower, freely rearwardly projecting and smooth support such as a pair of carrier spears, the web by the wrapping being wrapped underneath this support and subsequently is brought to leave the support together with the bale by an unobstructed movement over the free end of the support. 2. A method according to claim 2, whereby the supplied bales are loaded onto a feeding conveyor, which moves the bales rearwardly through the wrapping area and thereby at least contributes to a forward movement of this area by the force, with which the conveyor pushes the consecutive bales against the front end of the bale string so far produced. 3. A method according to claim 1, whereby the wrapping is effected by means of a belt or a pair of chains carrying the web supply reels and extending in linear stretches between preferably position adjustable diversion rollers or pulleys. 4. An apparatus for carrying out the method according to claim 1, comprising means for wrapping one or more sheet webs about successively supplied bales and means for moving the bales through the associated wrapping area, means being provided for carrying the bales in the wrapping area in a position free-to-be-wrapped, characterized in that the carrying means are constituted by lower, rigid and smooth supporting means such as a carrier plate or a pair of carrier spears, which, from an infeed area at the foremost end of the wrapping area projects in a free-carried manner rearwardly towards, optionally to or past, the rear end of the wrapping area, these supporting means being designed with a small thickness in the height direction and located above the lower part of the path of movement of the wrapping means. 5. An apparatus according to claim 4 and comprising feeding and throughfeeding means in the form of a rearwardly conducting entrainment conveyor. 6. An apparatus according to claim 5, in which there is provided, in connection with the said conveyor, a weighing system for weighing the received bales, preferably for determination of the dosing of a treating agent for injection into the bales by associated means for effecting such an injection. 7. An apparatus according to claim 4, in which the wrapping means comprise a belt or a pair of cords or chains carrying one or more sheet web supply means and extending in straight runs between preferably position adjustable diverter rollers or pulleys.

Inventors: KORSGAARD EBBE, KORSGAARD, EBBE
Applicants: KORSGAARD EBBE, KORSGAARD, EBBE
Application year: 1992
Main classification: B65B11
IPC codes: A01F15, A01F25