Patent Description:
Bundling machines for hay bales or similar material are known, of the type which group the bales, forming a vertical pack inside a bale bundling chamber which is disposed vertically on the frame of a machine. These machines have the main advantage that their length is very small, unlike other types of machines that gather the bales forming a pack that extends horizontally on the frame.

Machines that form vertical bale packs, such as, for example, that described in patent <CIT>, group the bales according to a bundling system comprising a pushing device arranged to insert bales into the bundling chamber through a bale entrance of the bundling chamber, a vertically displaceable bale lifting platform mounted to displace the bales from a lower position to an upper position within the bundling chamber, and retaining means to retain the bales in the upper position when the lifting platform recovers its initial lower position.

According to the bundling system described in the aforementioned patent, a transport device moves the bales one by one from a loading mouth to the entrance of the bundling chamber where the pushing device introduces the incoming bales of a layer into the interior space of the bundling chamber. Subsequently, the lifting platform vertically displaces the incoming bales of each layer to an upper position where the retaining means hold the layer so that the lifting platform can regain its lower position, pending reception of bales of a new layer. When the layer loading cycle of the pack ends, the lifting platform holds the group of bales stacked inside the chamber to allow the bundle to be bound. A rear door of the bundling chamber is then opened, and an ejector element acts to release the bundle and deposit it on the field while the tractor is under way. Subsequently, the packs deposited on the field are collected and stored to be transported by trucks or containers.

In practice, the bundling system described in the aforementioned patent has the disadvantage that it does not provide a sufficiently compact pack of bales, with a firm and tight binding intended to facilitate the handling of the pack, and which minimizes the risk that the pack becomes undone when handled.

In fact, although it is known that the width of the interior space of the bundling chamber where the pack is formed is desirable to conform as much as possible to the value resulting from the sum of the nominal width "A" of the bales of a layer, in practice, this is not possible, since, when the actual width of the bales is greater than the nominal, for example, due to an excessive humidity of the plant material or due to the variability of bale dimensions according to the baler, the lifting platform presents difficulties to move the bales vertically to the upper position. In practice, the dimensions of the inner space of the bundling chamber are loosely designed to facilitate that the layers of bales can be displaced vertically without problems, regardless of the humidity, the type of plant material or the dimensions of the bales. However, this results in obtaining a pack that is not very compact.

In view of the above, it is clear that there is a need to obtain a bale-bundling system that makes it possible to form compact packs of bales, which facilitate subsequent handling in the field, minimizing the risk of undoing the pack and facilitating the optimization of the space occupied by the pack during transport.

The aim of the present invention is to solve the aforementioned drawbacks by providing a bale bundling system with the advantages that will be described below.

In accordance with this objective, according to a first aspect, the present invention provides a bale bundling system for forming a pack of bales of hay or similar material according claim <NUM>.

According to a second aspect, the present invention provides a method for forming a bundled pack of hay bales or similar material according to claim <NUM>.

According to a third aspect, the present invention provides a bundling machine for forming a pack of bales of hay or similar material according to claim <NUM>.

For one embodiment, the bundling machine comprises a conversion kit for adjusting the width "a" of the interior space of the bundling chamber. In particular, a conversion kit to adapt the width "a" of the interior space of the bundling chamber to form a pack with bale layers each formed by a plurality of bales of nominal width "A" equal or greater than <NUM> each bale, for example, to form a pack with bale layers each formed by two bales of nominal width "A" of <NUM> each bale. Alternatively, the conversion kit allows adapting the width "a" of the interior space of the bundling chamber to form a pack with bale layers each formed by three or more bales of nominal width "A" equal or lower than <NUM>, for example, formed by three bales of nominal width "A" of <NUM> each bale.

Advantageously, said conversion kit comprises a bale-lifting platform extension removably attachable to the existent bale-lifting platform and a rear wall of the bundling chamber displaceable mounted on at least one pair of guides to be able to adjust the width "a" of the interior space of the bundling chamber as a function of the nominal width "A" of the bales that form a layer of bales of the pack.

In the present invention, the pushing device that inserts the layer of bales into the bundling chamber includes a compressing surface adapted to apply an active compression force on the layer of bales, in a transverse "X" direction of the pack and against the rear wall of the bundling chamber, while the lifting platform displaces the layer to the upper position. Thanks to this, the width "a" of the interior space of the bundling chamber can be designed with an adjusted value, without fear that the humidity of the plant material, or the dimensions of the bales, may cause problems when moving the bale layer vertically.

In fact, it has been observed that, by actively compressing the layer transversely against the rear wall of the bundling chamber while the lifting platform moves the layer to the upper position, the width "a" of the bundling chamber can be even less than the value resulting from the sum of the nominal width "A" of the bales that form the layer, without the risk that the dimensions of the bundling chamber are not adequate, for example if the humidity of the vegetal material is not the desired one, or the actual width of the bales is greater than the nominal width "A". In addition, it has been observed that, by reducing the dimensions of the bundling chamber, the walls of the chamber itself can passively compress the layers once the lifting platform recovers its initial position. As a result, an extremely compact pack with a very low risk of becoming undone is obtained that, in addition, significantly optimizes the space occupied by the packs to facilitate their transport.

Preferably, according to an embodiment of the bundling system, the processing and control means, for example, a processing and control unit, is configured to send a compaction signal to the bale lifting platform for the lifting platform applies on the bales an active compression force in a longitudinal "Y" direction of the pack at the end of a bale loading cycle of the pack.

Thus, at the end of the loading cycle, for example, when the lifting platform vertically displaces the last layer of bales, the lifting platform applies a longitudinally active compression force on the bales that allows the stacked bale pack inside the bundling chamber to be vertically compacted.

Advantageously, the interior space of the bundling chamber comprises a width "a" in a transverse direction "X" of the pack that is equal to or less than the value resulting from the sum of the nominal width "A" of the bales of a layer. For example, the width "a" of the bundling chamber can be designed with a value of <NUM> less than the value of <NUM> resulting from the sum of the nominal width "A" of <NUM> of two bales that form the layer.

In this way, the front and rear walls of the bundling chamber itself are susceptible to applying a passive compression force on the bales in a transverse direction once the bales lose contact with the compressing surface of the pushing device. In this way, the claimed system makes it possible to obtain an extremely compact pack, both in the transverse and longitudinal direction of the pack. The passive compression force applied by the front and rear walls of the bundling chamber limits the transverse expansion of the pack when the lifting platform applies the active compression force, at the end of the loading cycle. As a result, the breakage of the straps of the bales, frequent in the systems of the state of the art, is avoided.

Preferably, the compressing surface of the bales comprises a pushing plate sized so as to provide a contact surface with the bales equal to or greater than <NUM><NUM>, advantageously, a contact surface comprised between <NUM><NUM> and <NUM><NUM> suitable to provide the aforementioned active compression force on the bales in the transverse "X" direction of the pack, where preferably, the active compression force that is applied to the bale layer is comprised between <NUM>/cm<NUM> and <NUM>/cm<NUM>.

Again preferably, the drive means of the pushing plate comprise a parallelogram mechanism and the pushing plate is articulately attached to a pair of pivoting arms of the parallelogram mechanism. The parallelogram mechanism allows the plate to be displaced by maintaining a substantially vertical position inside the bundling chamber, maximizing the contact surface with the bales throughout the travel.

According to a preferred embodiment, the parallelogram mechanism is mounted so that the pivoting arms and the pushing plate hang over the bale receiving surface, the articulation of the parallelogram mechanism being configured so that the pushing plate is susceptible to oscillate on the bale receiving surface while maintaining contact with the bales, to horizontally displace the bales and apply the active compression force in the transverse direction "X", inside the bundling chamber.

Advantageously, the ends of the pivoting arms are attached and rotatably articulated to the corresponding pivot axes, the pivot axes being arranged such that a lateral projection in the plane of the parallelogram mechanism represents said pivot axes aligned according to an inclined line forming an acute angle with the horizontal.

In the present invention, the pusher plate oscillates up to <NUM>° about the bale receiving surface actuated by the parallelogram mechanism, maintaining a substantially vertical position, in contact with the bales. The pivot axes of the pivoting arms of the parallelogram mechanism are mounted such that the arms are susceptible to being collected in a rear position so that the bales can be positioned opposite the entrance of the bundling chamber. In the forward position, the pushing plate penetrates into the bundling chamber while maintaining contact with the bales.

According to one embodiment, the bundling chamber comprises a rear wall, wherein at least one portion of the rear wall of the bundling chamber defines a pack unloading door, the system comprising fixing means for blocking the opening of the unloading door when the pushing surface applies the compression force on the bales and against the rear wall of the bundling chamber. Advantageously, according to one embodiment, the fixing means comprise:.

In this way, the fastening member acts to prevent the unloading door from opening when the pushing surface applies the active compression force on the bales and against the rear wall of the bundling chamber. The electromechanical device may comprise, for example, a motor or a magnetic interlock.

According to a preferred embodiment, the system comprises an adjusting mechanism for adjusting the width "a" of the bundling chamber to modify the width "a" of the interior space of the bundling chamber, based on the nominal width "A" of the bales of the layer.

Thanks to this, the system is suitable for use with bales of different nominal widths "A", for example, of nominal width "A" of <NUM>, <NUM>, or <NUM>. Thus, depending on the nominal width "A" of the bale, the user can adjust the width "a" of the bundling chamber so that the passive compression force applied to the plant material of the pack is optimal. Table <NUM> shows, by way of example, different values of reduced width "a" of the bundling chamber suitable for applying a passive compression force on the layer of bales.

Preferably, the processing and control means, for example a processing and control unit connected operatively to the bale bundling system, is configured to send the compaction signal to the actuation means for actuating the compressing surface so that the compressing surface applies a predetermined active compression force value based on the value of the width "a" of the interior space of the bundling chamber.

According to one embodiment, the adjustment mechanism comprises the rear wall of the bundling chamber mounted displaceable on at least one pair of guides to be able to adjust the width "a" of the interior space of the bundling chamber as a function of the nominal width "A" of the bales and/or the moisture content of the material of the bales.

Preferably, the rear wall of the bundling chamber comprises a rear wall portion acting as the lower unloading door of the pack, wherein said rear wall portion is pivotally mounted clockwise on at least one pair of mounted skids displaceable on at least one pair of lower guides, and a rear wall portion acting as the upper door, wherein said rear wall portion is pivotally disposed counter clockwise on at least one pair of mounted skids displaceable on at least one pair of upper guides.

Optionally, for the embodiment of the bundling machine comprising the conversion kit for adjusting the width "a" of the interior space of the bundling chamber, the conversion kit comprises;.

Thus, with the claimed system, it is the rear wall of the chamber itself that defines the lower unloading door and the upper unloading door. Besides, the width "a" of the bundling chamber can be adjusted and/or adapted to form packs including bale layers with a plurality of bales of nominal width "A" selected from a range between <NUM> and <NUM>.

The closing of the two doors is ensured by means of fixing means that act by blocking the opening of the doors, so that both doors are able to withstand the active compression force of the compressing surface of the pushing device.

Advantageously, the fixing means comprise at least one fluid-dynamic element, or electromechanical device, arranged to actuate a force multiplier mechanism associated with a fastening member of both doors, for example, at least one fastening member configured to act as a staple. Preferably, said fluid-dynamic element, or said electromechanical device, is mounted displaceable along the transverse direction "X" of the pack to adapt the position of the fixing means to the width "a" of the bundling chamber. For example, one end of the fluid dynamic element may be displaceable mounted on a side wall of the bundling chamber by a threaded rod mechanism.

As discussed, the system includes retaining means for retaining or holding the bales in the upper position when the lifting platform recovers its initial lower position. According to an embodiment, the retaining means comprise a bale retaining device that is articulately attached to a wall of the bundling chamber, preferably, articulately attached to the rear wall of the chamber, the retaining device comprising at least one retaining member for retaining bales in the upper position, wherein said retaining member is associated with a parallelogram mechanism, the retaining member being susceptible to being displaced linearly along the transverse "X" direction of the pack when the parallelogram mechanism is actuated for retaining the bales inside the bundling chamber.

Thanks to these characteristics, the retaining member acquires a deployed position that is susceptible of contacting the bales laterally and uniformly within the bundling chamber, providing optimal fastening of the pack while the machine is travelling on the irregular surface of the field.

Advantageously, the system includes processing and control means, for example, a processing and control unit, configured to send a packet retention signal to actuation means associated with the retaining device so that the retention member moves linearly a predetermined distance based on the value of the width "a" of the interior space of the bundling chamber.

Preferably, the system comprises a plurality of binding units distributed aligned in correspondence with the bale entrance of the bundling chamber, each of the binding units being susceptible to provide one turn of yarn on the bale pack, the system including at least one element that acts as a pivot and is arranged adjacent to the binding units, on the outside of the bundling chamber, to guide the turn of yarn on the pack from the outside of the bundling chamber, according to an upward trajectory "T" inclined with respect to the surface of the pack.

Thus, it has been observed that the binding operation of the pack is improved, since the inclined section of trajectory facilitates the tensioning of the yarn so that the binding operation is carried out by tightening the yarn to the pack in an optimal way.

According to one embodiment, the system comprises four distributed binding units aligned in correspondence with the bale entrance of the bundling chamber so as to be able to bind by means of four turns of yarn, packets formed by bales of a nominal length "L" equal to or greater than <NUM>, for example, a nominal length "L" comprised between <NUM> and <NUM>, and a fifth distributed binding unit aligned to the four binding units so as to be able to bind, by means of five turns of yarn, packets formed by bales of nominal length "L" equal to or greater than <NUM>, for example, bales whose nominal length "L" is comprised between <NUM> and <NUM>.

It has been observed that the system of the present invention is optimal for also working with bales of nominal length "L" greater than <NUM>, which requires the application of a fifth string or turn of yarn in the pack. The systems of the state of the art present difficulties when working with bales of this nominal length "L" since the application of the fifth turn of yarn results in a greater risk of overturning of the layer of bales when this layer is introduced into the bundling chamber and moved to the upper position. In the system claimed, the compressing surface of the pushing device holds the bales and prevents the overturning of the layer, actively compressing the bales against the wall of the bundling chamber while the lifting platform vertically displaces them to an upper position.

Preferably, the bundling system comprises an ejector device of the pack of bales provided with a plurality of ejector members, preferably of at least four ejector members of bales, wherein said ejector members each comprise a first member section associated with the front wall of the bundling chamber, and a second member section associated with an upper wall of the bundling chamber, the second member section of each of the ejector members being articulately attached to the upper wall of the bundling chamber, so that the set of ejector members pivots with respect to the front wall and the upper wall of the bundling chamber to accompany the removal of the pack when the ejector device is actuated.

The present invention provides a bundling system and method for forming bundles of hay bales or similar material which, in their different embodiments, greatly improves the existing systems and methods in the state of the art, allowing the obtaining of extremely compact bundles formed by bales that can be from <NUM> to <NUM> in nominal length "L", advantageously, bales from <NUM> to <NUM> in nominal length "L" each bale.

The pack layers may be formed by two or more bales on which an active compression force is applied in the transverse direction "X" of the pack and against the rear wall of the bundling chamber, by means of the plate of the pushing device. Thanks to this, the width "a" of the inner space of the bundling chamber can be designed with a very tight value, which can be even lower than the value resulting from the sum of the nominal width "A" of the bales that form a layer, without the risk that the variability of dimensions of the bales prevents the layer of bales from being introduced into the bundling chamber when the actual width of the bales is greater than the nominal width "A".

At the end of the loading process, the lifting platform can apply an active compression force on the bale layers in the longitudinal direction "Y" of the pack, without causing a breakage of ropes or yarns by lateral expansion of the plant material, since the front and rear walls of the bundling chamber itself apply a passive compression force on the bale layers when the width "a" of the bundling chamber is less than the value resulting from the sum of the nominal width "A" of the bales that form a layer. It has been observed that this passive compression force that the layers receive facilitates the binding operation and significantly reduces the risk of undoing the pack during subsequent handling in the field, also optimizing the space that the pack occupies during transport.

For the better understanding of the description made herein, a set of drawings has been provided wherein, schematically, and solely by way of a non-limiting example, several practical cases of embodiments are represented.

An embodiment of the claimed bundling system and of the bundling machine incorporating the claimed system is described below, with reference to <FIG>.

The present invention relates to a bundling machine <NUM> for bales <NUM> incorporating the claimed bundling system to form a pack <NUM> of bales <NUM> of hay or similar material inside a bale bundling chamber <NUM>. This bundling chamber <NUM> has the peculiarity that it is disposed vertically on the frame <NUM> of the machine <NUM> to form a vertical pack <NUM> of bales <NUM> in the longitudinal direction "Y" of the pack <NUM>. The bundling machine <NUM> is suitable for bales of nominal length "L" comprised between <NUM> and <NUM>, or bales of nominal length "L" comprised between <NUM> and <NUM>.

The bundling chamber <NUM> of the bales <NUM> has an inlet 4a of bales which is arranged in correspondence with a receiving surface <NUM> which receives the bales <NUM> coming from a loading mouth <NUM>. As can be seen in <FIG> and <FIG>, the machine <NUM> incorporates a conveying device <NUM> that displaces the bales <NUM> from the loading mouth <NUM> to the receiving surface <NUM> located in front of the entrance 4a. The conveying device <NUM> of the machine <NUM> of <FIG> includes chains with traction elements as traction disks <NUM>, while <FIG> shows another embodiment, wherein the conveying device <NUM> includes conveyor belts <NUM>, instead of traction disks <NUM>, for displacing the bales <NUM>. The conveyor belts <NUM> have the advantage that they do not have mechanical traction elements drawn by chains. As a result, the bales <NUM> move on the conveyor belts <NUM> quickly and without risk of cord or string breakage <NUM> to the entrance 4a of the bundling chamber <NUM>, since no mechanical traction element penetrates the bale <NUM> during transport. In both <FIG> and <FIG>, the element <NUM> is seen as a pivot that serves as a support to guide the change of direction of the bales <NUM> between two substantially perpendicular conveying sections, and to lead the bales <NUM> towards the receiving surface <NUM> located in front of the entrance 4a of the bundling chamber <NUM>.

To introduce the bales <NUM> into the bundling chamber <NUM>, a pushing device has been provided that has the particularity that it includes a compressing surface 13a adapted and sized to apply an active compression force on the bales <NUM> in a transverse "X" direction of the pack <NUM>. In the embodiment described, the compressing surface 13a is that provided by a pushing plate <NUM> that is articulately attached to pivoting arms <NUM> of a parallelogram mechanism <NUM> hanging on the receiving surface <NUM> of the bales <NUM>. The dimensions of the compressing surface 13a of the pushing plate <NUM> are suitable to provide a contact surface with the bales <NUM> equal to or greater than <NUM><NUM>, for example, a contact surface comprised between <NUM><NUM> and <NUM><NUM>, suitable to apply on the bales <NUM> an active compression force equal to or greater than <NUM>/cm<NUM>.

The pushing plate <NUM> is actuated by a fluid-dynamic cylinder <NUM> that acts on the parallelogram mechanism <NUM>, so that the pushing plate <NUM> can be displaced maintaining a substantially vertical position while oscillating from a retracted position to an advanced position (see <FIG>).

In the embodiment described, the parallelogram mechanism <NUM> is mounted in such a way that the pivoting arms <NUM> hang from a structure 5a of the frame <NUM> of the bundling machine <NUM>, on the reception surface <NUM> for the bales <NUM>, and is configured in such a way that the lateral view of the mechanism <NUM> represents two axes <NUM>, <NUM> of rotation of the pivoting arms <NUM> arranged aligned forming an acute angle with the horizontal. Thus, in the retracted position, the pivoting arms <NUM> are collected so that the bales <NUM> can be positioned in front of the entrance 4a of the bundling chamber <NUM>, while, in the advanced position, the same pivoting arms <NUM> penetrate into the bundling chamber <NUM> in order to apply the active compression force on the bales <NUM>.

Inside the bundling chamber <NUM>, a lifting platform <NUM> is provided that is mounted vertically displaceable to be able to move a layer <NUM> of two incoming bales <NUM> to an upper position, where a retaining device <NUM> retains the bales <NUM> so that the lifting platform <NUM> can recover its initial lower position.

The images of <FIG> show a working sequence of the system on a layer <NUM> formed by two bales <NUM>, wherein the value resulting from the sum of the nominal width "A" of the two bales <NUM> exceeds a reduced width "a" of the bundling chamber <NUM> (see <FIG>). <FIG> and <FIG> show the compressing surface 13a of the pushing plate <NUM> applying on the bales <NUM> of the layer <NUM> an active compression force in the transverse "X" direction of the pack <NUM> and against the rear wall 4c of the bundling chamber <NUM>, while the lifting platform <NUM> displaces the layer <NUM> vertically to an upper position. In the upper position shown in <FIG>, the front wall 4b and the rear wall 4c of the bundling chamber <NUM> exert a passive compression force on the bales <NUM> of the layer <NUM>, since the bundling chamber <NUM> has a reduced width "a". <FIG> shows the layer <NUM> retained in the upper position by the retaining device <NUM>, while the platform <NUM> recovers its lower position awaiting a new layer. The retainer device <NUM> is articulately attached to the rear wall 4c of the bundling chamber <NUM> via a parallelogram mechanism <NUM>.

The images of <FIG> show a working sequence of the system on a pack <NUM> formed by seven layers <NUM> of bales <NUM>, at the end of a loading cycle, when the lifting platform <NUM> moves to lift the last layer <NUM> of bales. <FIG> shows the lifting platform <NUM> applying on the bales <NUM> an active compression force in the longitudinal direction "Y" of the pack <NUM>, to compress the pack <NUM> vertically. <FIG> also shows one of the complete turns of a yarn <NUM> that surrounds the pack <NUM> of bales <NUM>, and its corresponding needle <NUM> that holds the yarn <NUM>. Also shown is an element <NUM> that acts as a pivot to guide the turns of yarn <NUM> from the outside of the bundling chamber <NUM>, according to an upward trajectory "T" inclined with respect to the surface of the pack <NUM>. In <FIG>, the needles <NUM> that hold the respective yarns <NUM> have been displaced to a higher position in order to form the binds that bind the pack <NUM>. The inclined upward trajectory "T", which includes each of the yarn turns <NUM>, facilitates the tensioning of the yarn <NUM> so that it is tight to the pack <NUM>, while reducing the length of yarn <NUM> necessary to carry out the binding operation.

According to one embodiment, the claimed machine <NUM> includes a plurality of binding units <NUM> distributed aligned in correspondence with the entrance 4a of bales <NUM> of the bundling chamber <NUM>. Each of these binding units <NUM> provides one of the turns of yarn <NUM> on the bale pack <NUM>. In a preferred embodiment, four of the binding units <NUM> are distributed aligned to be able to bind, using four turns of yarn <NUM>, the packs <NUM> formed by bales <NUM> of nominal length "L" comprised between <NUM> and <NUM>, while a fifth binding unit <NUM> is distributed aligned with the other four, but in an outer lateral position displaced to be able to bind, using five turns of yarn <NUM>, packs <NUM> formed by bales <NUM> of nominal length "L" equal to or greater than <NUM>, for example bales <NUM> of length "L" comprised between <NUM> and <NUM> (see <FIG>).

The systems of the prior art do not include the fifth binding unit, since experience shows that this results in a greater risk of overturning of the layer <NUM> of bales <NUM> due to the effect of contact with the yarns <NUM>, when the layer <NUM> is introduced into the bundling chamber <NUM>. In the system claimed, unlike the systems of the state of the art, the compressing surface 13a of the pushing device <NUM> holds the bales <NUM> inside the bundling chamber <NUM>, preventing the overturning of the layer <NUM>, while the lifting platform <NUM> moves the layer <NUM> vertically. As a result, the claimed bundling system may include more than four binding units <NUM>, for example, five, six or even seven binding units, so that it is optimal for working with bales of nominal length "L" comprised between <NUM> and <NUM>.

According to a preferred embodiment, the claimed system includes an adjustment mechanism for adjusting the width "a" of the bundling chamber <NUM> as a function of the nominal width "A" of the bales <NUM> that form each layer <NUM>. Thanks to this, the system is suitable for use with bales <NUM> of different nominal "A" widths, for example, of nominal "A" width of <NUM>, <NUM> or <NUM>. Thus, depending on the nominal width "A" of the bales <NUM>, the user can adjust the width "a" of the bundling chamber <NUM> to cause the front wall 4b and the rear wall 4c of the bundling chamber <NUM> itself to apply a passive compression force on the layers <NUM> of bales <NUM> in a transverse direction "X" of the pack <NUM>.

For example, the width "a" of the bundling chamber <NUM> can be designed with a value of <NUM>, which is lower than the value of <NUM> resulting from the sum of the nominal width "A" of <NUM> of two bales <NUM>. In this way, the claimed system makes it possible to obtain an extremely compact pack <NUM>, both in the transverse and longitudinal direction of the pack, since the passive compression force applied by the front 4b and rear 4c walls of the bundling chamber <NUM> limits the lateral expansion of the layers <NUM> of the pack <NUM>, when the lifting platform <NUM> longitudinally presses the layers <NUM>, at the end of the loading cycle. As a result, the breakage of the strings of the bales, frequent in systems of the prior art, is also avoided.

In the embodiment shown in the figures, the rear wall 4c of the bundling chamber <NUM> comprises a wall portion 4c that acts as the lower unloading door <NUM> of the pack <NUM> and a wall portion 4c that acts as the upper unloading door <NUM> of the pack <NUM>. In order to expand or reduce the width "a" of the interior space of the bundling chamber <NUM>, both unloading doors <NUM>, <NUM> are pivotally mounted on respective skids <NUM>, <NUM>, which, in turn, are mounted displaceable on respective guides <NUM> and <NUM> on which both doors <NUM> and <NUM> are horizontally moved (see <FIG>).

<FIG> and <FIG> are schematic side views of the bundling machine <NUM> of <FIG>, showing the bundling chamber <NUM> adjusted to two different working widths "a". <FIG> shows the bundling chamber with a greater working width "a" once the lower unloading door <NUM> and the upper unloading door <NUM> of the rear wall 4c have been displaced horizontally outwards on the skids <NUM> and <NUM> and their respective guides <NUM> and <NUM>.

In order to ensure the closing position of both unloading doors <NUM>, <NUM>, and prevent these doors <NUM>, <NUM> from being opened when the compressing surface 13a applies the active compression force on the layer <NUM> of bales, the claimed system includes fixing means that act by blocking the opening of both unloading doors <NUM>, <NUM>.

In the embodiment described and shown in the figures, the fixing means include at least one staple-like fastening member <NUM>, a force multiplier mechanism <NUM> associated with said fastening member <NUM>, and a fluid-dynamic element <NUM>, e.g., a hydraulic cylinder, for actuating the multiplier mechanism <NUM>. <FIG> and <FIG> show the fixing means mounted on a side wall 4d of the bundling chamber <NUM>, wherein the fastening member <NUM> is in the closing and locking position, holding supports <NUM> integrally attached to the doors <NUM>, <NUM> of the rear wall 4c of the bundling chamber. The fluid-dynamic element <NUM> has the peculiarity that it is mounted displaceable on the side wall of the bundling chamber <NUM>, by means of a threaded rod mechanism <NUM>, which allows adapting the position of the fixing means to the width "a" of the bundling chamber <NUM> (see <FIG>).

<FIG> shows a perspective view of the rear wall portion 4c of the bundling chamber <NUM> acting as the lower unloading door <NUM> and including the retaining device <NUM> for retaining the layers <NUM> in the upper position, when the lifting platform <NUM> recovers its initial lower position. As can be seen in this <FIG>, and also in <FIG>, the retainer device <NUM> includes four retaining members 21a associated with a parallelogram mechanism <NUM> mounted on the wall portion 4c itself acting as the lower door <NUM> of the bundling chamber <NUM>. Thanks to these features, when the multiple parallelogram mechanism <NUM> is actuated, the retaining members 21a move linearly so that they can contact the bales <NUM> uniformly, ensuring effective retention without damaging the layers <NUM> of bales <NUM> (see <FIG>). In the retracted position, the retaining members 21a are hidden between the bars that configure the lower unloading door structure <NUM> (see, for example, <FIG>).

<FIG> is a rear perspective view of the bundling machine <NUM> of <FIG> showing the ejection of the pack <NUM> of bales <NUM> accompanied by an ejector device <NUM> including four ejector members 38a of the pack <NUM>. In this figure the lower unloading door <NUM> and the upper unloading door <NUM> can be seen open, once the fastening member <NUM> of the doors <NUM>, <NUM> has released the holding supports <NUM> to allow both unloading doors <NUM>, <NUM> to pivot on the respective support skids <NUM>, <NUM>, actuated by two fluid dynamic cylinders <NUM>, <NUM>. The ejector members 38a are associated with the front wall 4b and the upper wall 4e of the bundling chamber <NUM> so that they pivot relative to these walls 4b, 4e to accompany the removal of the pack <NUM> while the machine <NUM> is traveling through the field drawn by a tractor (not shown).

<FIG> and <FIG> represent depicted in grey colour components of a conversion kit intended to adapt the width "a" of the interior space of the bundling chamber <NUM> to form pack of bales with nominal width "A" equal or greater than <NUM>, for example bales of nominal width "A" of <NUM>. Alternatively, the conversion kit allows adapting the width "a" of the interior space of the bundling chamber to form a pack with bale layers each formed by three or more bales of nominal width "A" equal or lower than <NUM>, for example, formed by three bales of nominal width "A" of <NUM> each bale.

For the illustrated embodiment of <FIG> and <FIG>, the conversion kit includes a bale-lifting platform extension <NUM>' removably attachable to the existent bale-lifting platform <NUM>, a first pair of skid extensions <NUM>' removably attachable to the existent at least one pair of skids <NUM> mounted displaceable on the pair of lower guides <NUM>, and a second pair of skid extensions <NUM>' removably attachable to the existent at least one pair of skids <NUM> mounted displaceable on a pair of upper guides <NUM>.

As can be seen in <FIG>, for this particular embodiment, the rear wall portion 4c acting as a lower unloading door <NUM> is mounted so as to pivot clockwise on said first pair of skid extensions <NUM>', and the rear wall portion 4c acting as an upper unloading door <NUM> is mounted so as to pivot counter clockwise on said second pair of skid extensions <NUM>'.

Next, the way of operation of the claimed bundling system is described with reference to <FIG>. In particular, a method for forming a bundled pack <NUM> of bales <NUM> of hay or similar material on the frame <NUM> of the bundling machine <NUM> claimed is described, wherein the bundle <NUM> of bales <NUM> is disposed vertically on the frame <NUM>, in a longitudinal direction ("Y") of the pack <NUM>.

Initially, the bales <NUM> move successively from the loading mouth <NUM> to the receiving surface <NUM> of the bale <NUM> located in front of the entrance 4a of the bundling chamber <NUM>, employing the bale <NUM> conveying device <NUM> (see <FIG> and <FIG>).

The two bales <NUM> forming the first layer <NUM> of bales <NUM> are successively introduced into the bundling chamber <NUM> by means of the pushing device that contacts the bales and moves them horizontally, one by one, on the receiving surface <NUM> for the bales <NUM>. Once the layer <NUM> is loaded, the compressing surface 13a of the pushing plate <NUM> applies an active compression force on the layer <NUM> in the transverse "X" direction of the pack <NUM> and against the rear wall 4c of the bundling chamber <NUM>, while the lifting platform <NUM> moves the layer <NUM> vertically to an upper position inside the bundling chamber <NUM> (see <FIG> and <FIG>).

According to a preferred embodiment in which the width "a" of the bundling chamber <NUM> is less than the value resulting from the sum of the nominal width "A" of the two bales <NUM> of the layer <NUM>, the front wall 4b and the rear wall 4c of the bundling chamber <NUM> exert a passive compression force on the plant material of the layer <NUM>, once the layer <NUM> has moved to the upper position (see <FIG>). The retaining device <NUM> is then actuated to retain the layer <NUM> in the upper position and allow the lifting platform <NUM> to regain its initial position awaiting a new layer <NUM> (see <FIG>).

The previous working sequence is repeated successively to load a certain number of layers <NUM> of bales <NUM>, until reaching the end of the loading cycle (see <FIG>). At this moment, the lifting platform <NUM> travels again vertically inside the bundling chamber <NUM>, to apply an active compression force on the layer <NUM> of bales <NUM> in the longitudinal direction "Y" of the pack <NUM>, so that the plant material of the pack <NUM> is compressed vertically (see <FIG>).

According to the aforementioned preferred embodiment, in which the bundling chamber <NUM> has a reduced width "a", the passive compression force exerted by the front wall 4b and the rear wall 4c of the bundling chamber <NUM> limits the lateral expansion of the layers <NUM> when the lifting platform <NUM> vertically compresses the pack <NUM>. As a result, the breakage of the yarn of the bales <NUM> is avoided and it is easier to obtain an extremely compact bale pack <NUM>, which is bound with yarn <NUM> using four or more turns of yarn <NUM>, for example, five turns of yarn <NUM> or six turns of yarn <NUM>, depending on the nominal length "L" of the bales <NUM>.

In order to unload the pack <NUM>, first, the fastening member <NUM> is released which fastens the holding supports <NUM> of the lower door <NUM> and the upper door <NUM> of the bundling chamber <NUM>. Next, the fluid-dynamic cylinder <NUM> of the upper door <NUM>, the fluid-dynamic cylinder <NUM> actuating the ejector device <NUM>, and finally the fluid-dynamic cylinder <NUM> of the lower door <NUM> are actuated (see <FIG>).

The claimed system and method has the particularity that, before starting the loading and forming process of the pack <NUM>, the user can decide whether or not to modify the width "a" of the interior space of the bundling chamber <NUM>, depending on the nominal width "A" of the bales <NUM> to be handled, or even depending on the humidity of the plant material in the bales <NUM>, since humidity modifies the nominal dimensions of the bales <NUM>. In any case, thanks to the claimed system, the width "a" of the inner space of the bundling chamber <NUM> can be modified with an adjusted value, which can be even lower than the value resulting from the sum of the nominal width "A" of the bales that form the layer <NUM>, without the risk that a higher actual width of the bales <NUM> prevents the layer <NUM> of bales <NUM> from being introduced into the inner space of the chamber <NUM>.

Claim 1:
A bale (<NUM>) bundling system for forming a pack (<NUM>) of bales (<NUM>) of hay or similar material, said pack (<NUM>) comprising a plurality of layers (<NUM>) of bales (<NUM>), said bales (<NUM>) having a predetermined nominal width ("A"), comprising:
- a frame (<NUM>) capable of being attached to and pulled by a tractor,
- a bale (<NUM>) receiving surface (<NUM>) on the frame (<NUM>),
- a bale (<NUM>) bundling chamber (<NUM>) arranged on the frame (<NUM>) to form a pack (<NUM>) of bales (<NUM>) disposed vertically in a longitudinal direction ("Y") of the pack (<NUM>), the bundling chamber (<NUM>) comprising a bale (<NUM>) entrance (4a) disposed in correspondence with the bale (<NUM>) receiving surface (<NUM>),
- a pushing device arranged to introduce bales (<NUM>) into the bundling chamber (<NUM>) through the bale (<NUM>) entrance (4a) of the bundling chamber (<NUM>),
- a vertically displaceable bale-lifting platform (<NUM>) mounted to displace bales (<NUM>) from a lower position to an upper position within the bundling chamber (<NUM>), and
- retaining means (<NUM>) for retaining bales (<NUM>) in the upper position when the lifting platform (<NUM>) recovers its initial lower position,
characterised in that:
- the pushing device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprises a compressing surface (13a) adapted to apply on a layer (<NUM>) of bales (<NUM>) an active compression force according to a transverse direction ("X") of the pack (<NUM>), inside the bundling chamber (<NUM>),
- wherein said system comprises processing and control means configured to send a compaction signal to actuation means (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) associated with the compressing surface (13a) so that the compressing surface (13a) applies the active compression force on the layer (<NUM>) of bales (<NUM>), while the lifting platform vertically displaces the layer (<NUM>) in the interior space of the bundling chamber (<NUM>).