Abstract:
A sheathing method includes the steps of depositing a bale on a sheathing carrier. The bale is pushed onto the carrier and slides on the carrier base plate against the preceding bale using a pusher-ejector device. A pushing motion of the pusher-ejector device causes a handling equipment to simultaneously move the tractor attached to the handling in a direction opposite to the direction of the pushing motion. The movement of the tractor is caused by a cross piece arranged beneath the frame of the pusher-ejector device. The carrier has a stop integral with the two rails that define the base plate. The cross piece contacts the stop to move the carrier by a step corresponding to a length of the bale in the same direction as the tractor.

Description:
BACKGROUND OF THE INVENTION 
     This invention concerns a method for sheathing bales of plants, fodder or other, under a plastic film. 
     This invention also relates to the material used for sheathing bales of plants, fodder or other, under plastic film, round bales as well as parallelepipedic bales. 
     This material consists on the one hand of a storing and drawing frame for the plastic film in order to form a kind of funnel, as described in the document CA-111 546 for round bales and, on the other hand, loading means that enable placing the bales one after the other into said funnel. 
     The drawing frame is mounted on a carrier that is, moreover, suitably arranged upstream of said drawing frame, for accommodating, centring and guiding each bale as it is pushed into the funnel whose inlet is formed and held open with sufficient diameter by said drawing frame. 
     The carrier can be moved as the bales are inserted, as described in the document GB-2 227 220, by a step corresponding to the length of these bales, directly by the vehicle that handles the bales, i.e. a transport vehicle such as a farming tractor fitted for example with a loading arm or similar. 
     Handling these bales on the fields does not enable accurate positioning of the bales on the carrier or reliable sheathing; the latter operation calls for a certain skill on the operator&#39;s part. 
     SUMMARY OF THE INVENTION 
     This invention suggests means that enable simplification of this sheathing operation and especially ensure fast execution of said operation. 
     Besides, the method according to the invention enables improvement of the compacting of the bales with respect to one another inside the sheath. Preferably, this sheath is made of plastic material; it is preferably stretched to enable insertion of the bales and then, after leaving the drawing frame, it resumes its normal position while compressing the periphery of the bales. 
     The sheathing method according to the invention using a sheath-carrier that moves as the sheath is being filled, consists: 
     in handling a bale by means of a transport vehicle fitted with a handling tool that is for instance equipped with spindles, 
     in laying the bale on the carrier, upstream of the plastic film storage supports making up said sheath, 
     in pushing the bale inside the sheath, resting against the previous bale, 
     in moving the carrier by a step matching the length of the bale, which operation that consists in pushing the bale uses the handling tool equipped to that effect with a pusher-ejector device whose movement causes, by reaction, the reverse motion of said vehicle by means of said handling tool, whereas said tool is arranged to drive and move the sheathing carrier simultaneously over a distance corresponding to the length of the bale laid last on said carrier. 
     This method enables using a relatively simple tool. The sheathing carrier does not need any permanent energy source. It has a passive role throughout the sheathing operation. 
     The invention also relates to the handling tool mounted on a vehicle such as a farming tractor or similar, for implementing the method, which tool comprises a frame on which is mounted at least a pair of spindles, a pusher-rejector integrated to the spindle-carrying frame, behind said spindles, which frame comprises fastening means to the three-point coupling system, at the front or the rear of the tractor or still, according to the situation, to the end of a loading arm with which said tractor is equipped. 
     According to a preferred embodiment of the invention, the pusher-ejector device consists of a pair of compasses retracted inside the frame of the handling tool and that extend under the effect of a hydraulic actuator, for instance, controlled form the tractor by the operator, the pair of compasses extend over a distance that is at least equal to the length of the bale, in order to eject said bale from the spindles and to move simultaneously by reaction, the tractor and the sheathing carrier by a step corresponding to the distance travelled by the pusher, i.e. at least the length of the bale ejected. 
     Still according to the invention, the pair of compasses consist—of a first leg whose length corresponds more or less to the width or the diameter of the bale, which leg is articulated at one of its ends on an axle integral with the spindle-carrying frame and, —of a second leg articulated at the other end of the first leg, and that is fitted at its free end, with a pusher centered more or less on the longitudinal axis of the tractor, which first leg is mobile under the effect of an actuator that is mounted don the spindle-carrying frame and this first leg causes, when moving, the second leg to extend so that said pusher remains more or less centered on said longitudinal axis throughout its travel. 
     Still according to the invention, the second leg extends using a chain or cable that winds around a pulley section that is centered on its axis of articulation, at the end of the first leg of the pair of compasses, which cable is integral at one of its ends, with said sector of the second leg and at its other end, with the spindle-carrying frame at one point selected to enable displacement of the pusher along the longitudinal axis of the tractor, i.e. along a line more or less on the middle vertical plane of the spindles, or still the middle vertical plane of the bale to be laid on the sheathing carrier and picked up by said spindles. 
     Under certain operating conditions, the cable of the pusher may become slack and leave its guiding system at the angle of the pair of compasses. 
     This invention suggests using a roller chain, a double chain for instance, to ensure extension of the pair of compasses, which double roller chain advantageously maintains high stiffness on a plane that is perpendicular to the axis of its rollers, i.e. on the extension plane of the pair of compasses, which plane is for example horizontal. 
     Still according to the invention, the spindle-carrying frame comprises at its lower section, a crosspiece in the form of a heel or shoe that, on the one hand, serves as a marker to the operator with respect to the ground, to enable accurate spindling of the bales and, on the other hand, serves as a coupling means for pulling the sheathing carrier, by reaction during the ejection of the bale pushed onto the spindles, which member co-operates to that effect with a stop integral with said carrier. 
     The invention also concerns the sheathing carrier for implementing the method, which carrier co-operates with the handling tool and comprises, upstream of the drawing frame, a kind of base plate consisting of the upstream section of the rails integral with the frame of said carrier, and that extend over a length equal to at least twice the length of a bale, which rails are cantilever at their downstream end, i.e. on the sheathing side, and they comprise a fixed or removable stop system at their upstream end that co-operates with the heel or shoe of said tool in order to move said carrier by reaction, when the bale is ejected by means of the pusher of said handling tool. 
     According to another embodiment of the invention, the position of the stop on the rails is adjustable to suit the length of the bales and these rails may also comprise a second stop arranged downstream, preferably removable to enable sheathing of the last bale for example; this second removable stop is situated at a distance from the upstream stop that is at least equal to the length of a bale. 
     Taking into account the size and the weight of the bales, the invention suggests a stop system that makes handling of the bales easier, and in particular their placement on the carrier. 
     To that effect, the carrier comprises an area for laying the bales in the form of a base plate, made preferably of two rails separated by a distance that corresponds more or less to the radius of said bales; these guiding rails are situated as low as possible with respect to the ground and are extended downstream of the base plate in order to form a tilted plane at the inlet of the carrier; the space between the upstream extensions of the rails is able to accommodate a plate that co-operates to guide the bales as they are positioned by the tractor and the tool associated with said tractor. This guiding plate is articulated around a transversal and horizontal axis arranged at the upstream end of the legs of the rails, maintained elastically in a protruding position and capable of being retracted automatically when a bale is inserted. This plate also serves as a stop system and co-operates with the handling tool. The latter comprises a crosspiece in the form of a heel or shoe that retracts the plate automatically, and the latter can play a warning role as it resumes its normal stop positions soon as the handling tool has reached its normal bale unloading position. In this position, the stop is interposed between the crosspiece of the frame of the handling tool and the tractor vehicle, which causes during the ejection of the bale, by simple reaction, i.e. when the pusher of said tool rests on the bale, the tractor and the carrier simultaneously to move back, whereas the tractor is pushed directly by the frame of the handling tool whereas the carrier is pulled by said frame thanks to the stop installed upstream of said carrier. 
     Such arrangement of the inlet of the carrier with a stop in the form of a guiding late, limits vertical displacement of the bale and of the handling tool to the strict minimum. 
     The frame of the handling tool comprises, on the side of the tractor vehicle, means that enable to fasten it directly to the three-point coupling system of said tractor, as well to the rear or to the front of the tractor according to the equipment of said tractor, or to a carrier device mounted at the front of said tractor. 
     Moreover, this handling tool may fit other bale handling means such as for instance a barrel-type loading device such as described in the document FR-2 530 117; in such a case, there are as many handling tools as bales, for example three tools arranged in a star pattern. 
     Still according to the invention, the upstream section of the rails carrying the stop, forms a kind of frame that is articulated on said rails or the chassis of the carrier, around a horizontal and transversal axis, which frame is foldable at a right angle and lockable in this retracted position by means of tension rods or similar and said chassis and said frame are arranged to enable fastening of said carrier to the conventional three-point coupling system of a tractor in order to move the carrier as required. In such a case, the handling tool can be placed on the carrier, to be transported by the latter. 
     According to another embodiment of the invention, the carrier comprises at the guiding rails, guides to protect the plastic film during the introduction of the bales, which guides also enable centering of the bales in the funnel formed by the plastic sheath stretched on the drawing frame arranged on the carrier. 
     Still according to the invention, the chassis of the carrier is arranged in order to place the guiding rails of the bales as close to the ground as possible. In their upstream section, the rails are situated at a height compatible with the normal lifting capacity of a tractor when the latter is fitted with a handling tool fixed directly to its three-point lifting system. In their downstream section, the rails are situated a few centimetres above the ground, no more than 10 cm, so that generally these rails form a guiding plane that delineates an angle S with respect to the ground of approximately 5 to 7°. 
     The equipment according to the invention is also advantageously compact. The length of the guiding rails of the bales, downstream of the stop, is approximately twice and a third of the bales. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will also be detailed using the following description and appended drawings given for exemplification purposes, and on which: 
     FIG. 1 represents, in a schematic lateral view, the sheathing carrier with the portion of a farming tractor fitted with a bale handling tool; 
     FIG. 2 shows an assembly variation of the handling tool that is carried by a lifting arm with which a farming tractor is equipped; 
     FIG. 3 represents, in the form of a functional diagram, the elements making up the handling tool with the pair of compasses in retracted and extended positions; 
     FIG. 4 represents a lateral view, and still in the form of a functional diagram, of certain elements making up the handling tool, with the pair of compasses in an extended position; 
     FIG. 5 is a schematic diagram of the carrier seen from above, with notably the drawing frame, the guiding rails and the stop system; 
     FIG. 6 is a schematic diagram of the front section of the carrier showing the upstream end of the guiding rails, and the stop in a position retracted by a bale that is carried by the handling tool; 
     FIG. 7 shows the stop in active position when the bale rests on the carrier, before implementing the pusher; 
     FIG. 8 shows the system arranged at the front of the carrier to enable fastening it to a three-point coupling of a tractor. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 shows schematically the carrier  1  on which lie bales  2  that are fed by a tractor  3 . 
     The tractor  3  comprises, conventionally, a three-point type coupling system  4  on which is mounted the frame  5  of a tool  6  enabling to handle the bales  2 . The three-point coupling system co-operates with anchoring points  7  arranged on the vertical face  9  of the frame  5 . 
     The three-point coupling system  4  has sufficient clearance to collect the bales  2  on the ground and to raise them to sufficient height before presenting them to the inlet of the carrier  1 , on a base plate  10  consisting for example of a pair of rails  11  arranged longitudinally. 
     The frame  5  of the handling tool comprises spindles  12  that engage into the bale  2  halfway up. An additional spindle  12 , arranged at the lower section of the frame  5 , can engage into the lower section of the bale, to improve its stability with respect to the handling tool. 
     The length of these spindles is for example approximately half the length of a bale  2 . 
     The three-point coupling system comprises, conventionally, two lower coupling bars  13  and according to the handling requirements, a third telescopic point consisting of an actuator  14 . 
     This actuator  14  enables tilting the frame  5  of the handling tool  6  as required to assist, for instance, the placement of the bales on the carrier, before the drawing frame  16 . 
     The bales  2  are placed one behind another in a sheath  17 . This sheath  17  is stored in the form of superimposed layers  19  at the drawing frame  16 , which layers are carried by supporting arms  20  arranged for instance in such a fashion as to form a six-sided polygon for sheathing round bales or to form a square for sheathing parallelepipedic bales. These supporting arms  20  pull the layers  19  of the sheath apart, thereby forming a kind of funnel to enable the passage of the different bales  2 . 
     The carrier  1  is capable of moving on the ground. It comprises to that effect wheels  21  arranged at the base plate  10  and, at the rear, it may comprise pads  22  and/or wheels as well. Preferably, the frame of the carrier and its rails  11  are tilted with respect to the ground by an angle S of 5-7° for example and the downstream end of said rails is very close to the ground, a few centimetres, ten or so, to enable smooth formation of the sheath and of the bale ‘sausage’. 
     The handling tool  5  compromise a pusher  25  detailed below in relation to FIGS. 3 and 4, which pusher resses the bale  2  against the bale laid previously that is situated downstream of the drawing frame  16 . When the pusher  25  touches and bears against the face  2 ′ of the bale that it is carrying, it rests on the latter and it is the frame  5  of said pusher  25  that moves by reaction, driving the tractor  3  and the carrier  1  that, as it moves, unwind the layers  19  automatically in order to pack up the last bales. 
     The travel C of the pusher  25 , FIG. 3, corresponds at least to the length of a bale  2  and the length of the guiding rails  11  is greater than twice the length of a bale. The rails  11  can also be extended at their downstream section in order to hold the bale longer, once it has left the drawing frame  16 . 
     The displacement of the carrier  1  by reaction is caused by the presence of a stop  26  arranged upstream of the base plate  10  between extensions  11 ′ situated at the front end of the rails  11 . This stop  26  co-operates with a crosspiece  27  arranged under the frame  5  of the handling tool. When the bale  2  carried by the tool is fed onto the base plate  10 , this crosspiece  27  extends above the upstream end of the rails  11 , between the face  2 ′ of the bale  2  in question and the active section of the stop  26  detailed below. 
     FIG. 2 shows an assembly variation of the handling tool  6 . Said tool is fixed on a loading arm  30  mounted conventionally at the front of the tractor  3 . This arm  30  comprises at its front end a plate  31  whose movement around the axis  32  is controlled by an actuator  33 . The anchoring points  7  of the tool  6  are attached to the plate  31  provided to this end. 
     The operation of the handling tool  6  is the same, whatever its situation on the tractor, which tractor may besides comprise several tools provided at the front and at the rear. 
     FIGS. 3 and 4 represent in the form of functional diagrams, the handling mechanism of the pusher of the tool  6 . 
     The movement of the pusher  25  is obtained for instance by means of a compass-type device comprising a pair of compasses accommodated in the spindle-carrying frame  5 . These pair of compasses that are advantageously compact, consist of a first leg  35  whose length is close to the width or the diameter of the bale  2  if the bale is round. This leg  35  is articulated on an axle  36  integral with the frame  5 . This first leg is initially vertical and comprises at its free end a second leg  37  articulated around an axis  39  provided at the end of said first leg, which second leg  37  comprises at its other end, the pusher  25  mounted on an axle  40 . 
     The first leg  35  us mobile by means of an actuator  41  that is attached to an axle  42  integral with the frame  5 . The operator controls this actuator from the tractor. The extension of the first leg  35  around its articulation axis  36  causes the second leg  37  to pivot round the axis  39  that is common with the first leg  35 . 
     The purpose of this pivoting is to maintain the pusher  25  and in particular its axle  40  on the longitudinal axis of the tractor, which axis also corresponds to the middle vertical plane of the carrier when the loader has laid a bale on said carrier. 
     The pusher  25  is articulated on the axle  40  and held by a low tension spring  43  that tends to bring it back to the leg  37 . 
     The co-ordinated movement of the legs  35  and  37  of the pair of compasses is performed using a cable or a chain  44 , that reels around a circular sector  45  in the form of portion of a pulley or of a pinion for instance; this sector  45  is centered on the articulation axis  39 , integral with said second leg. The cable or chain is attached at its end  46  on an extension of the sector  45 , in an adjustable fashion and at its other end to a fixed point  4  integral with the frame  5 , which point  47  is selected in order to obtain quasi-rectilinear displacement of the pusher  25 , along the longitudinal axis of the tractor, as mentioned previously. 
     It can be noted that a large portion of the cable  44  is situated between the first leg  35  and the actuator  41 . 
     The link between the actuator  41  and the leg  35  uses a cap  48  through which runs the chain  44 , and the actuator  41  is articulated on this cap by means of an axle  49 . 
     A return spring  50  is interposed between the first and the second leg to maintain the cable  44  in traction and to enable automatic return of said second leg. 
     The chain  44  consists preferably of a double roller chain as represented separately on FIG.  3 . This roller chain is advantageously rigid on a plane that is perpendicular to the axis of its rollers, which plane corresponds to the spreading lane of the pair of compasses, i.e. a horizontal plane. 
     FIG. 4 also shows the spindles  12  that are integral with the frame  5 , locked in orifices  51 . The pusher  25  extends between both spindles  12  below the level of the latter for example. 
     It can be noted on FIG. 3 that the travel C of the pusher  25  between its inactive position where it is situated on the plane of the assembly face of the spindles  12  and its active position when the dihedron consisting of the leg  35  and the leg  37 , is completely extended under the effect of the actuator  41  and of the chain  44 . 
     This travel C is first of all vastly greater than the length of the spindles  12  to enable ejection of the bale and, as mentioned previously, it is greater than the length of the bales  2 , for example approximately one and a quarter times the length of the bales  2 . 
     The first leg  35  is articulated on the axis  36  that is integral with the spindle-carrying frame  5 . The anchoring point  47  of the chain or of the cable  44  can still be seen, as well as the axle  42  on which is articulated the actuator  41  that serves for controlling the first leg  35 . 
     The first leg  35  is articulated on the axle  36  that is integral with the spindle-carrying frame  5 . The anchoring point  47  of the chain or of the cable  44  can still be seen, as well as the axle  42  on which is articulated the actuator  41  that serves for controlling the first leg  35 . 
     FIG. 1 shows that the upstream extensions  11 ′ of the rails are tilted towards the ground, forming a kind of ramp to assist the insertion of the bale  2 . Between these extensions  11 ′, we can see, as represented on FIG. 5 as well, the stop  26  that is in the form a rectangular plate filling up the space between the extensions  11 ′. This stop serving as a guide is articulated on a horizontal transversal axle  62 , at the front end of the extensions  11 ′. An elastic return system in the form of a spring  63  enables holding the stop  26  in active position, i.e. in such a position that its downstream end face  64  can grab the crosspiece  27  of the frame  5 , as represented on FIGS. 1 and 7. 
     Tabs  65 , visible on FIGS. 6 and 7, limit the travel of the stop  26  when it comes back into active position after the passage of the tool  6  and in particular of its crosspiece  27 . Sudden return of the stop  26  to active position is indicated by a characteristic warning clatter, that informs the operator and enables him to initiate the bale ejection and sheathing procedure. 
     FIG. 1 shows the length LR of the rails  11  between the active face  64  of the stop  26  and the downstream end of said rails. 
     This length LR is approximately twice and a third the length of the bales  2 . It comprises the length of the base plate LS, plus the length of a bale L and an additional rest LA for the sheathed bale in order to maintain said bale in an intermediate position between the ground and the carrier. 
     The length LS of the base plate  10 , between the face  2 ′ of the bale that is situated in the drawing frame  16  and the active face  64  of the lock  26 , is substantially greater than the length LM of a bale increased by the distance between the pusher  25  and the active face of the crosspiece  27  of the handling tool. These different alterations enable to obtain a compact and particularly efficient equipment. 
     The transversal middle axis  66  of the drawing frame  16  is situated at a distance LB from the downstream end of the rails  11  that is approximately equal to one third of their length LR. 
     FIG. 8 shows additional means provided at the front of the carrier  1 , i.e. in its upstream section, to assist its displacement on the ground, by means of the tractor. 
     The front end of the frame of the carrier  1  comprises anchoring points  75  that co-operate for example with the lower lifting arms  13  of a conventional coupling system. The third anchoring point is provided at the front end of a transversal bar  76  that connects the upstream ends together of the extensions  11 ′ of the rails  11 . 
     The third point  79  is provided on this crosspiece  76 , in its central section. 
     The extensions  11 ′ form with the crosspiece  76 , a kind of frame, FIG. 5, that is articulated around an axle  80  arranged horizontally and transversally above the level of the hooks  75 . The extensions  11 ′ are mounted on the caps  81  articulated on the axle  80  and the rails  11  are cut slantwise. 
     The position of the cuts  82  of the rails  11  and that of the axle  80  are such that they enable the front end of the assembly consisting of the extension  11 ′, of the stop  26  and of the third point  79  to be tilted vertically. In such a position, this assembly is held by means of tension rods  84  interposed between these axles  85  arranged laterally on the rails  11  of the carrier or on the frame of said carrier, and axles  80  arranged for example at the ends of the crosspiece  76 . 
     The sheathing carrier can be handled notably to install it on the site or to start a new sausage-like silo. 
     Handling can also take place upon completion of an on-site operation and then, the handling tool can be dismantled and laid on the carrier. 
     Additional bars  87  arranged halfway up the bale can also be provided, on either side of the bale, for improved guiding and insertion into the drawing frame without any possible damage of the plastic film of which the sheath is composed. 
     Similarly, at the lower section of the base plate  10 , as represented on FIGS. 1 and 5, guides  88  can be placed, that enable locking and guiding the bale  2  at the inlet of the drawing frame, always with a view to avoid any attacks on the plastic film  9 . 
     These guides  88  consist of metal plates integral with the rails  11 , arranged on either side of said rails, in the lower section of the drawing frame. 
     FIG. 5 also shows between the rails  11  and upstream of the drawing frame  16 , a removable stop  26 ′, represented as a thin mixed line. This second stop  26 ′, similar to the upstream stop  26 , enables pushing the last bale beyond the drawing frame  16  when the handling tool is installed as represented on FIG. 2, on a loading arm  30 . The stop  26 ′ co-operates with the handling tool as detailed previously for the stop  26 . 
     If the handling tool  6  is installed on the lifting arms of a tractor, as represented on FIG. 1, the last bale can be cleared while interposing a space whose length corresponds to that of the bales between the pusher  25  and the face  2 ′ of the bale that is inside the drawing frame  16 . Then the sheathing procedure is performed as detailed previously.