BINDING ARRANGEMENT FOR A BALING PRESS

Description

[0001] The present invention relates to a binding arrangement for a baler according to the preamble of claim 1 and to a baler with such a binding arrangement according to claim 15.

[0002] Balers are used in agriculture to compress previously collected crops such as hay or straw into bales. The crop is usually picked up from the ground by a pick-up that is integrated into the baler. In the case of a square baler, the collected crop is compressed in two stages. First, the crop taken up by the pick-up and possibly cut by a cutting device is conveyed further by a conveyor and / or collecting device within a collecting chamber, where it is gathered and / or pre-compacted. A pressing chamber or pressing channel is arranged downstream of the collecting chamber. There, an oscillating press piston acts on the crop and carries out the actual pressing. The pre-compacted crop is thus transferred portion by portion into the pressing channel, where the square bale is gradually built up.

[0003] Once the square bale has reached a required size, it is bound using a binding agent before being ejected. The binding agent can be, for example, a thermoplastic band. This is looped around the bale, with two ends of a binding agent strand being joined together by friction welding, for which purpose a welding unit is provided for each binding agent strand. Before, during, and after the welding process, it is necessary to secure one or more strand sections using clamping units. In the prior art, it is known to operate each individual welding unit with its own compressed air motor. This system works reliably, but has various disadvantages. The multiple motors in the area of ​​the welding units further restricts the installation space, which is already limited by the adjacent clamping units and other elements.The situation is further complicated by the fact that the motor must be adjusted along with the welding unit when switching between a welding position and a passive position. Multiple motors increase production costs and compressed air consumption.

[0004] EP 3 391 733 A1 discloses a generic binding arrangement.

[0005] The object of the invention is to propose an improved possibility for operating the welding units in a binding arrangement of a baler.

[0006] The object is achieved with a binding arrangement for a baler, having the features of independent patent claim 1. Advantageous embodiments can be found in the dependent claims.

[0007] For this purpose, a binding arrangement is provided for a baler which is designed to form a crop bale in a pressing channel and to wrap it with at least one strand-shaped binding agent, wherein the binding arrangement has a plurality of welding units offset from one another with respect to a transverse axis, each of which has an oscillatingly drivable friction head for friction welding two strand sections of at least one binding agent strand, wherein the binding arrangement has at least one welding motor for driving the friction heads.

[0008] The baler is usually a square baler or large square baler. The baler can be self-propelled with its own drive or as a trailer without its own drive. It has a baling chamber in which the actual bale formation and pressing process take place. The baling chamber has a longitudinal axis to which it usually runs at least predominantly parallel. The longitudinal axis of the channel can coincide with a longitudinal axis of the baler, but it can also be inclined relative to it. Typically, a pressing piston is arranged in the baling chamber, which is designed to act on the crop with an oscillating movement and thus compress it. With regard to the crop flow, a collecting chamber is usually arranged upstream of the baling chamber, in which a conveyor and / or collecting device is designed to convey the crop further and pre-compact it.

[0009] To secure the shape of the finished bale, it is provided with a binding agent within the baling channel. The binding agent, which can also be referred to as binding material, can in particular be a thermoplastic band (for example made of PET). It is normally placed around the bale in a plurality of separate loops that are spaced transversely to the longitudinal axis of the channel. In either case, the crop bale is wrapped in binding agent. The binding arrangement primarily serves to connect two strand sections of a binding agent strand and thus close one of the loops in a ring around the crop bale. As a rule, a separate binding device of the binding arrangement is provided for each loop, so that the baler can have a plurality of binding devices, for example between two and eight binding devices.

[0010] The binding arrangement has a plurality of welding units offset from one another with respect to a transverse axis. The transverse axis here and below is generally a transverse axis of the binding arrangement, which, however, is generally equivalent to a transverse axis of the baler. The same applies to the longitudinal axis and the vertical axis. Preferably, each welding unit can be part of an above-mentioned binding device, which can also have further elements, in particular at least one clamping unit. Normally, each of the welding units serves to close one of the above-mentioned loops by welding two sections of the same binding material strand. The welding units, as well as the binding devices, can be of identical design. Each welding unit has an oscillating friction head for friction welding two strand sections of at least one binding material strand.The friction head has a friction surface that is normally aligned along a plane, but may have a profile, meaning it may not be completely flat and smooth. The friction head is brought into contact with one strand section while the other strand section rests against it. To ensure sufficient contact pressure and sufficient force and / or form fit between the friction head and the strand section, the welding unit can have a friction head counterholder against which the two strand sections rest on a side opposite the friction head. As will be explained below, the friction head counterholder can simultaneously be a clamping element of an adjacent clamping unit or be connected to such a clamping element.The actual welding takes place by oscillating the friction head, which creates friction between it and a strand section, between the strand sections, and / or between a strand section and the friction head counterholder. This causes heating and plasticization or even partial liquefaction of the binding material, whereby the two strand sections are bonded together. This bond remains intact even after cooling and complete solidification of the binding material. The friction head, which serves to create the bond, can be movably mounted on a friction head carrier, relative to which it performs its oscillating movement. The friction head carrier can consist of several individual parts, some of which may not have any contact with the friction head.

[0011] The binding assembly also includes at least one welding motor for driving the friction heads. The at least one welding motor is configured to generate a drive force, at least during the welding process, which can be transmitted to the friction heads to drive them.

[0012] According to the invention, the binding arrangement comprises a gear mechanism for the simultaneous drive connection of a welding motor to a plurality of friction heads. This means that the drive force of a single welding motor can be divided by means of the gear mechanism and used to simultaneously drive several friction heads. In general, the gear mechanism can comprise any desired elements for transmitting, redirecting, stepping up and / or reducing a force and / or torque. Overall, the gear mechanism serves to branch the power flow from one welding motor to several friction heads. Particularly preferably, the gear mechanism is designed for the simultaneous drive connection of one welding motor to all friction heads, i.e. the drive force of one welding motor is distributed to all friction heads by the gear mechanism.The gearbox is preferably coupled to exactly one welding motor, although it would be conceivable within the scope of the invention for two welding motors, for example, to each proportionally introduce a drive force into the gearbox, which is then distributed by the gearbox to the friction heads in the manner described. The drive force can be distributed equally, but it would also be conceivable for some friction heads to be driven more strongly than others. Since the friction heads are only used during part of the binding process, which in turn only represents a (normally small) part of a bale formation and binding cycle, it is sensible not to drive them continuously. In this case, it is possible to either deactivate the welding motor or interrupt the power transmission through the gearbox. This means that the gearbox can optionally have a clutch that can be temporarily disconnected.

[0013] A key advantage of the invention is that the number of welding motors required can be significantly reduced, typically to a single welding motor. Compared to a binding arrangement in which each friction head is driven by its own welding motor, this generally results in a cost and / or weight advantage, even if the individual welding motor in the binding arrangement according to the invention is heavier and / or more expensive in itself. These advantages are not negated by the gearing required by the invention. Above all, there are advantages with regard to the available installation space, since the individual welding motor generally takes up less installation space than a plurality of welding motors as a whole.In addition, the individual welding motor can be positioned in a suitable location with sufficient installation space, from which the drive force is transmitted via the gearbox to the individual friction heads. The gearbox, in turn, can be implemented using small and / or slim components, so that gearbox components assigned to different friction heads do not collide with each other. A further advantage is that fewer supply lines are required to operate a single welding motor than to operate multiple welding motors.

[0014] The design and drive of the welding motor are fundamentally not specified within the scope of the invention. However, it is strongly preferred that the welding motor be designed as a hydraulic motor. The hydraulic motor is connected to a hydraulic circuit and is driven by it. This design is advantageous because a hydraulic system is generally required for various elements of the baler anyway and therefore does not have to be created specifically for the hydraulic motor. Furthermore, the possible achievable speed with a hydraulic motor is generally less dependent on the load - i.e. usually the torque to be applied - than, for example, with a pneumatic or electric welding motor. This also applies if the hydraulic motor is comparatively small.Typically, the hydraulic system is connected to an external hydraulic supply, typically powered by a tractor's drive motor, or it is pressurized by at least one baler pump, which in turn is mechanically coupled to the drive motor. The speed achievable by the hydraulic motor is normally proportional to the drive motor's speed. Since the drive motor's speed can vary, the hydraulic motor's speed also varies depending on the situation, resulting in a different oscillation frequency of the individual friction head. On the one hand, however, the resulting variations are usually manageable, so that effective welding is still possible even at a low drive motor speed.On the other hand, a lower oscillation frequency of the friction head can be compensated for by applying it to the strand sections for a longer period. Accordingly, a shorter application of the friction head at a high oscillation frequency can prevent overheating and thus damage to the strand sections. This aspect will be discussed further below.

[0015] The transmission preferably has a distributor arrangement which connects the welding motor to a plurality of transmission paths, each of which is coupled to a friction head. In this embodiment, the branching of the power flow and thus the distribution of the drive force is carried out by the distributor arrangement. This can also be referred to as a distributor gear. The transmission as a whole could also be characterized as a distributor gear, in which case the distributor arrangement can be referred to as a distributor section. The distributor arrangement is connected to the welding motor and receives the drive force from it. Furthermore, it is connected to individual transmission paths to which it proportionally passes on the drive force. In the respective transmission path, there is preferably no further distribution of the drive force, but merely a transmission, optionally combined with a reduction or transmission ratio.Both the distribution arrangement and the respective transmission path can have one or more elements.

[0016] According to one embodiment, the friction heads are spaced apart from the welding motor with respect to the longitudinal axis, wherein each transmission path has a transmission shaft extending at least partially along the longitudinal axis. This embodiment allows a high degree of design freedom with regard to the positioning of the welding motor. It can be arranged in a position in which sufficient installation space is available. The distance along the longitudinal axis is at least partially, preferably predominantly, bridged by the transmission shafts. The distributor arrangement, on the other hand, can have a comparatively small extent in the direction of the longitudinal axis and extend predominantly along the transverse axis. All longitudinal shafts can run parallel to one another. In particular, they can run parallel to the longitudinal axis.

[0017] The power transmission from the welding motor to the respective transmission shaft could be achieved in various ways, for example via gears and / or chains. However, particularly due to the normally high speeds or rotational speeds within the transmission, it is preferred that the transmission shaft on the welding motor side have a first shaft pulley, which interacts with a drive belt of the distributor arrangement. This means that the distributor arrangement has at least one drive belt, which can be designed as a toothed belt, for example. This transmits the drive force coming directly or indirectly from the welding motor to the transmission shaft by engaging with the first shaft pulley. In the case of a toothed belt, this is also a toothed pulley.It is possible for a transmission shaft on the welding motor side to have two first shaft pulleys that interact with two drive belts. The drive force can be transmitted to the transmission shaft via one first shaft pulley and passed on via the other first shaft pulley.

[0018] A wide variety of options are available regarding the number and arrangement of the drive belts in the distributor assembly. Designs are conceivable in which the number of drive belts corresponds to the number of transmission shafts. On the other hand, it is also conceivable for the drive force to be transmitted from the welding motor to all transmission shafts by a single drive belt. An advantageous design provides for the distributor assembly to have a welding motor drive belt that interacts with a welding motor pulley directly coupled to the welding motor and at least one first shaft pulley, as well as at least one shaft drive belt that interacts with two first shaft pulleys, bypassing the welding motor pulley. The welding motor drive belt thus receives the drive force directly from the welding motor via the welding motor pulley and transmits it to at least one transmission shaft.The shaft drive belt, on the other hand, does not receive the drive power directly from the welding motor, but rather from a transmission shaft, which in turn may be driven by the welding motor drive belt, for example. This drive power is passed on to at least one other transmission shaft. A wide variety of configurations are conceivable in this context. For example, two transmission shafts located closest to the welding motor can be driven by the welding motor drive belt, and from these transmission shafts, the drive power can be passed on via a shaft drive belt to the next transmission shaft, from there to the next one, and so on.

[0019] On the friction head side, the transmission shaft can have a second shaft pulley, which acts via a friction head drive belt on a friction head pulley coupled to the friction head. This means that power is transmitted again here via a further drive belt. This power transmission can in particular take place at least partially in the vertical direction, i.e. the second shaft pulley and the friction head pulley can be vertically offset from one another. In particular, the second shaft pulley can be arranged higher. This makes it possible, for example, to guide the transmission shaft above various elements of the binding arrangement so that it cannot collide with them or impair their function. The friction head pulley can be rotatably mounted on the aforementioned friction head carrier.It performs a rotary movement which can be translated in different ways into a linear oscillating movement of the friction head, for example by means of an eccentric.

[0020] Preferably, a friction head carrier carrying the friction head is pivotable about a welding pivot axis between a welding position, in which the friction head is lowered to a welding plane in which it acts on a strand section, and a passive position. In the passive position, the friction head is removed from the welding plane, one could also say raised from it. In this case, it is preferably provided that a belt tensioner acts on the friction head drive belt, wherein a pulley rotation axis of the friction head pulley is arranged in the welding position on one side of a plane extending through a transmission shaft rotation axis of the transmission shaft and the welding pivot axis and is displaced towards the plane upon adjustment to the passive position. The function of the belt tensioner, which can be elastically pretensioned by a spring element, is to keep the friction head drive belt under tension while the friction head carrier is adjusted.It is important to ensure that the opposing belt strands between the second shaft pulley and the friction head pulley remain spaced apart, even if, for example, the belt tensioner presses one belt strand towards the other. This can be ensured with the configuration described above. A plane is considered that is spanned by the transmission shaft rotation axis of the transmission shaft and the welding pivot axis. In the welding position, the pulley rotation axis of the friction head pulley is arranged on one side of this plane. Normally this is the same side on which the friction head is arranged. If the friction head carrier is adjusted to the passive position, the pulley rotation axis moves towards the plane and can, in particular, move through the plane to the other side.

[0021] The binding arrangement is preferably designed such that the welding motor is activated before a control shaft, via which a deflection of at least one element of the binding arrangement can be controlled during a binding process, is coupled to a drive motor. The control shaft is rotatable relative to the main frame of the baler and can, for example, be coupled to the needle rocker. During the binding cycle, the control shaft is coupled to the drive motor via a coupling and rotates 360°, normally during the entire binding cycle. Said drive motor is normally a drive motor of a tractor, the drive force of which is mechanically transmitted to the baler. In principle, it could also be a drive motor of the baler, in particular a hydraulic motor. However, the speed of a hydraulic motor of the baler is also normally proportional to the speed of the drive motor of the tractor.The speed of the control shaft is therefore generally proportional to the speed of the tractor's drive motor. At least one element of the tying arrangement, for example a clamping element or a friction head carrier, is controllable via the control shaft. This means that an adjusting movement of the element is linked to the rotation of the control shaft. For example, the control shaft can have a cam track that interacts with a feeler lever, which in turn is connected to the aforementioned element. Such control is effective in itself, but has the disadvantage that such an element can only move when the control shaft begins to rotate, which in turn usually coincides with the start of movement of the needle rocker. Overall, therefore, there is little time left before the needle rocker has guided the strand section to be welded into the area of ​​the welding unit.It is therefore advantageous to start the reaming head beforehand, i.e., the welding motor should be activated before the control shaft is connected. The control shaft is normally connected depending on the current bale size, which is monitored by sensors. Accordingly, the welding motor can also be activated depending on the bale size. The bale is built layer by layer, and the control shaft is normally connected shortly before the last layer is added, which is required to achieve a target size. The welding motor could be activated shortly after the second-to-last layer has been added.

[0022] The binding arrangement is also advantageously designed such that the welding motor is deactivated depending on the angle of rotation of the control shaft. This means that the welding motor is deactivated when the control shaft has reached a predetermined angle of rotation. Since the speed of the control shaft is proportional to the speed of the drive motor, different time intervals, and therefore different welding durations, result depending on the speed of the drive motor. However, if the welding motor is operated as a hydraulic motor via the drive motor as described above, its speed is also proportional to the speed of the drive motor. Accordingly, the friction head performs a greater number of oscillations within a certain time interval at higher speeds. Conversely, the time interval is shortened at higher speeds. These two effects compensate each other, so that the number of oscillations remains the same.Accordingly, the friction head transfers approximately the same energy regardless of the speed, ensuring a sufficient weld is always achieved. Alternatively, it is also conceivable to measure the rotational speed of the welding motor and deactivate it after a specified number of revolutions. Another alternative is to deactivate the welding motor when a specified time interval has elapsed since the control shaft has reached a certain angle of rotation. In this case, it is advisable to select the length of the time interval based on the speed of the welding motor.

[0023] Preferably, each welding unit is assigned a clamping unit with two clamping elements that interact in a clamping position, wherein a friction head carrier carrying the friction head and a clamping element are mounted coaxially so as to be pivotable about a welding pivot axis, wherein the friction head carrier can be guided via an intermediate first spring element during a closing movement of the clamping element leading to the clamping position such that it precedes the clamping element. Various phases of the binding process may require securing the binding agent strand or a strand section. The clamping unit, which is designed to clamp at least one strand section of a binding agent strand, serves this purpose. The clamping unit has two clamping elements that interact in a clamping position and clamp the binding agent strand - if one is present. The clamping unit is adjustable between the clamping position and a release position.A friction head carrier, which carries the friction head, and one of the clamping elements are mounted coaxially so as to be pivotable about a welding pivot axis. For example, a shaft can be passed through the clamping element and the friction head carrier. However, the clamping element and the friction head carrier are not rigidly coupled to one another. Rather, a first spring element is interposed, which can be designed, for example, as a torsion spring, tension spring, or compression spring. This creates an elastic coupling during a closing movement of the clamping element, which moves the friction head carrier along. This means that both elements rotate in the same direction about the welding pivot axis. The coupling by the first spring element is coordinated so that the friction head carrier is moved ahead of the clamping element. Accordingly, it reaches its welding position before the clamping element reaches the clamping position.The clamping element then pivots further, building up a restoring force in the first spring element that determines the contact pressure of the friction head. At the same time, this reduces the clamping force of the clamping unit.

[0024] One embodiment provides that the clamping element is coupled to a positively guided drive element via an intermediate second spring element. The drive element can be coupled directly or indirectly to a motor in such a way that it is positively guided at least during the closing movement of the clamping element. The clamping element is coupled to this, but a second spring element is interposed so that elastic deflection between the clamping element and the drive element is possible. The drive element guides the clamping element into the clamping position, where its movement is stopped by the other clamping element and the intermediate strand section. Further movement of the drive element can lead to deformation of the second spring element, thereby preventing the clamping force from increasing excessively. The second spring element is preferably preloaded so that it only deforms above a certain clamping force.The force exerted by the second spring element is reduced by the force exerted by the first spring element.

[0025] In particular, the drive element can be a feeler lever which interacts with a cam track arranged on the control shaft and which interacts via a coupling rod with a crank arm which is connected in a rotationally fixed manner to the clamping element, wherein the second spring element is arranged between the feeler lever and the crank arm. The feeler lever can be pivotally mounted on the main frame of the baler or on a frame of the tying device. It is normally pretensioned in such a way that it at least temporarily maintains contact with the cam track and follows its course. The cam track is normally connected in a rotationally fixed manner to the control shaft. The feeler lever acts directly or indirectly on the coupling rod, which in turn acts directly or indirectly on the crank arm. The crank arm is in turn connected in a rotationally fixed manner to the clamping element with respect to the common axis of rotation of the clamping element and the friction head carrier.The function of the coupling rod is, on the one hand, to transmit force over a given distance and, on the other hand, to mediate the pivoting movements of the push-button lever on the one hand and the crank arm on the other. The second spring element is interposed between the push-button lever and the crank arm, with various options available.

[0026] According to one embodiment, the second spring element is arranged between a first rod part of the coupling rod connected to the crank arm and a second rod part that is deflectable relative to the first rod part and connected to the trigger lever. This means that the coupling rod is not designed as a rigid element but rather has two rod parts that can be deflected relative to one another. The second spring element is arranged between these rod parts and is generally preloaded. The preload is preferably adjustable while maintaining the length of the coupling rod. This means that a change in the preload does not change the length of the coupling rod.To achieve this, a rod part can in turn have two sub-elements which are adjustable relative to one another, wherein one sub-element has a stop for the other rod part and is connected to the crank arm (or the push-button lever), and the second spring element is pre-tensioned between the other sub-element and the other rod part, which is connected to the push-button lever (or the crank arm).

[0027] The welding pivot axis is preferably arranged below the welding plane. Normally, the welding plane runs at least approximately horizontally, although under certain circumstances, an inclination of, for example, a maximum of 10° relative to the horizontal may be present. In this context, "below" generally refers to a position on the side of the welding plane opposite the friction head. Due to the described arrangement, a pivoting movement of the friction head carrier, which lifts the friction head from the welding area, directly leads to a proportionally horizontal movement, which moves the friction head and the friction head carrier sideways out of the area of ​​the binder strand. The corresponding area can thus be exposed by pivoting through a comparatively small angle (for example, less than 80°). This shortens the time required to open as well as close the welding unit.

[0028] The invention also provides a baler configured to form a crop bale in a baling channel and to wrap it with at least one strand-like binding agent, wherein the baler comprises a binding arrangement according to the invention as described above. Advantageous embodiments of the baler according to the invention correspond to those of the binding device according to the invention.

[0029] The invention is described below with reference to figures. The figures are merely exemplary and do not limit the general inventive concept. They show Fig. 1 is a perspective view of a part of a baler according to the invention; Figs. 2A - 2C are highly schematic views of parts of the baler and a binding agent strand during different times of a binding cycle; Fig. 3 is a perspective view of a part of the baler from Fig.1 with a binding arrangement according to the invention; Figs. 4 and 5 are perspective views of a binding device of the baler from Fig. 1 ; Fig. 6 a perspective view of a part of the binding device from Fig. 4 ; Fig. 7 a partial sectional view of a coupling rod of the binding device from Fig. 4 ; and Fig. 8A-8BRear views of the binding device from Fig.4 during different times of the binding cycle.

[0030] Fig. 1 shows a perspective view of parts of a baler 1 according to the invention, more precisely a square baler. Here and in the other figures, the longitudinal axis X pointing backwards against the direction of travel, the transverse axis Y and the vertical axis Z are shown. Various components that are not relevant for understanding the invention have been omitted, for example a chassis and a drawbar, by means of which the baler 1 can be coupled to a towing vehicle. The invention is expressly not limited to towed or carried balers, but also relates to self-propelled balers. The baler 1 has a main frame 2. Within the main frame 2, a baling channel 3 is defined, which extends along a channel longitudinal axis A. The lateral and upper cladding of the baling channel 3 is partially omitted in the figure. Within the baling channel 3, a (in Fig. 2A bis 2C A (schematically shown) square bale 90 is successively built up from portions of crop that have been pre-compacted in a collection chamber not visible here. The crop is compacted in the baling channel 3 by an oscillating press piston 4. When the square bale 90 has reached its predetermined size, it is tied together using a binding agent, more precisely, a thermoplastic band. Several loops of binding agent, spaced apart from one another transversely to the longitudinal axis A of the channel, are placed around the square bale 90. A total of six loops can be produced here. To form the respective loop, a first strand section 101 of a binding agent strand 100, which is held at one end of the bale 90 at its upper side, is connected to a second strand section 102, which for this purpose is guided from below through the baling channel 3 and further to its upper side.This is achieved by means of six binding needles 8, which are part of a needle swing arm 7. The needle swing arm 7 is connected to a control shaft 6 in a manner not explained in detail here and can be driven by it. The control shaft 6 can be connected to a motor drive (not shown) via a clutch gear 5, so that it rotates about a control shaft axis B and the needle swing arm 7 is driven for a binding cycle.

[0031] The baler 1 has binding devices 11 which are arranged in Fig.1 are shown in a highly schematic cuboid shape. Each of the binding devices 11 is provided for producing one of the loops of binding material spaced apart from one another transversely to the channel's longitudinal axis A. Each binding device 11 has a front clamping unit 12, to which a separating element 15 is assigned, a middle clamping unit 17, to which a welding unit 20 is assigned, and a rear clamping unit 60. The binding device 11 also has a hold-down device 16.

[0032] The function of the individual elements is explained below using Fig.2A bis 2C explained.

[0033] Fig.2A represents a state shortly before the completion of the square bale 90, while a final layer of crop is added by the (not shown here) pressing piston 4. The first strand section 101, which forms an end section of the binding agent strand 100, rests on the upper side of the square bale 90 and is held at the end between a first front clamping element 13 and a second front clamping element 14 of the front clamping unit 12. The separating element 15 is rigidly coupled to the first front clamping element 13. The hold-down device 16 is inactive and may have only slight or no contact with the strand section 101. A first middle clamping element 18 and a second middle clamping element 19 of the middle clamping unit 17, as well as a friction head carrier 21 of the welding unit 20, are pivoted out of the plane of the drawing. Elements positioned outside the plane of the drawing in this way are here and in Fig.2B und 2C each represented by dashed lines. A sensor (not shown here) determined that only one more layer needed to be added to the square bale 90 to reach a predetermined target size. A welding motor 25 was then started, which drives a friction head 22 of the welding unit 20. This occurs before the control shaft 6 is connected to the motor drive via the clutch gear 5. Also before the control shaft 6 is coupled, the rear clamping unit 60 has already been closed, so that the first strand section 101 is enclosed between a first rear clamping element 61 and a second rear clamping element 62. The binding needle 8 guides a second strand section 102 of the same binding agent strand 100 as well as a third strand section 103 connected thereto upwards through the pressing channel 3.

[0034] Fig.2B represents a state in which the binding needle 8 has placed the second strand section 102 on the first strand section 101. The front clamping elements 13, 14 and the separating element 15 have been pivoted out of the plane of the drawing to make room for the binding needle 8. Since the first strand section 101 is clamped in place by means of the rear clamping unit 70, it is prevented from shifting or becoming completely lost. The hold-down device 16 has been adjusted such that it acts on the first strand section 101 from above and prevents it from protruding into the path of movement of the binding needle 8. The first middle clamping element 18 and the friction head carrier 21 are pivoted into the plane of the drawing and enclose the first strand section 101 between themselves and the second middle clamping element 19. The second front clamping element 14 is pivoted back into the plane of the drawing.By activating a friction head 22 arranged on the friction head carrier 21, the first strand section 101 and the second strand section 102 are friction welded.

[0035] The rear clamping unit 60 can now be released, with the first rear clamping element 61 being stationary in this case and thus remaining in the plane of the drawing. The hold-down device 16 is also released from the first strand section 101, being moved out between it and the second strand section 102. The front clamping unit 12 grasps the third strand section 103 connected to the second strand section 102, and the separating element 15 separates the second strand section 102 therefrom. This state is shown in Fig.2C After the strand sections 101, 102 have been welded, the middle clamping unit 17, including the friction head carrier 21, can be released and moved out of the plane of the drawing. The welding motor 25 can be deactivated, which here occurs depending on the angle of rotation of the control shaft 20. The now fully strapped square bale can be conveyed to the rear and ejected. The third strand section 103, gripped by the front clamping unit 12, takes over the role of the first strand section 101 in the next binding cycle.

[0036] Fig.3 illustrates the drive of the friction heads 22 of the individual welding units 20. The control shaft 6 and essential parts of the individual binding devices 11 have been omitted in order to make the underlying elements visible. A welding motor 25 designed as a hydraulic motor can be seen, which is attached to the main frame 2 and is arranged in front of the control shaft 6 with respect to the longitudinal axis X. In this area, there is sufficient space to accommodate the welding motor 25. The drive force of the welding motor 25 is transmitted to the individual friction heads 22 via a gear 26. The welding motor 25 has a welding motor pulley 28 which drives a welding motor drive belt 29. This, in turn, engages with two first shaft pulleys 32 which are attached to two transmission shafts 34. A total of six transmission shafts 34 are rotatably mounted relative to the main frame 2.The respective transmission shaft 34 is rotatably mounted about a transmission shaft rotation axis and, in this case, runs almost parallel to the longitudinal axis X, but is inclined by 5° in the direction of the vertical axis Z. Each of the two transmission shafts 34 driven by the welding motor drive belt 29 is in turn connected to a further transmission shaft 34 via a shaft drive belt 30, and this in turn is connected to a further transmission shaft 34 via another shaft drive belt 30. The drive torque of the welding motor 25 is thus passed on from one transmission shaft 34 to the next by means of the shaft drive belts 30. If two drive belts 29, 30 engage a transmission shaft 34, this transmission shaft 34 in this case has two first shaft pulleys 32; alternatively, however, both drive belts 29, 30 could also engage a single, correspondingly wide first shaft pulley 32.The welding motor drive belt 29, the shaft drive belts 30, and the shaft pulleys 32 form parts of a distribution arrangement 27, which in turn is part of a transmission 26. While the distribution arrangement 27 essentially divides the drive force, a plurality of a total of six transmission paths 31 serve to transmit the parts of the drive force further to the friction heads 22. Each transmission shaft 34 forms an essential element of a transmission path 31. With respect to the longitudinal axis X, near its rear end, each transmission shaft 34 has a second shaft pulley, which interacts with a friction head pulley 36 via a friction head drive belt 35. The friction head pulley 36, in turn, drives an eccentric in a manner known per se and not shown in detail here, which generates an oscillating movement of the friction head 22.The welding motor 25 is a hydraulic motor and can be operated via the same motor drive as the control shaft 6, namely via the drive motor of a tractor (not shown), which either drives a hydraulic system of the tractor to which the hydraulic motor is connected, or mechanically drives a pump (also not shown) of the baler 1. The speed of the welding motor 25 is therefore proportional to the angular velocity of the control shaft 6. Therefore, deactivation of the welding motor 25 at a certain angle of rotation of the control shaft 6 always leads to an (at least approximately) equal number of oscillations of the friction heads 22 and thus to an approximately equal energy input into the binding agent strand 100. Alternatively, the revolutions of the welding motor 25 can also be recorded, with deactivation occurring after a certain number of revolutions.Finally, it would be possible to deactivate the welding motor 25 after a predetermined time interval has elapsed.

[0037] Fig. 4 and 5 each show essential parts of a binding device 11, while Fig. 6 again shows a detailed view of the same. Some of the elements shown are arranged on a rigid binding frame, which is not shown here. A plurality of cam tracks 55-57 are connected in a rotationally fixed manner to the control shaft 6. In this case, three cam tracks are provided for each binding device 11, each of which interacts with a sensor lever 50, 51 that is pivotally mounted on the binding frame. As in Fig.4 As shown, a first curved path 55 interacts with a first feeler lever 50, which acts on the first middle clamping element 18 via a first coupling rod 41 in a manner explained below. It is coupled to a spring element 59 via a connecting element 58 (in this case a rod) and is prestressed by the latter in the direction of the first curved path 55. A second curved path 56 interacts with a second feeler lever 51, which interacts with the hold-down device 16 via a second coupling rod 52 and with the first front clamping element 13 via a third coupling rod 53. The second feeler lever 51 is prestressed by a spring element 59 in the direction of the second curved path 56.A third cam track 57 interacts with a third sensing lever (hidden in the figures) and interacts with the second central clamping element 19 via a fourth coupling rod 54 in order to pivot the latter about a pivot axis (without reference symbol) which is inclined here by 5° relative to the vertical axis Z and opposite to the longitudinal axis X.

[0038] The friction head carrier 21, the first middle clamping element 18 and the second front clamping element 14 can be pivoted coaxially about a welding pivot axis C, but are not connected to one another in a rotationally fixed manner. The first middle clamping element 18 is coupled to the friction head carrier 21 via a spring element 24. The spring element 24 transmits a torque so that when the first middle clamping element 18 pivots, the friction head carrier 21 is carried along in a leading position. This means that when the first middle clamping element 18 is pivoted into a clamping position towards the second middle clamping element 19, the friction head carrier 21 leads (for example by 3°) so that the friction head 22 connected to it comes to rest on the second middle clamping element 19 before the first middle clamping element 18, or on the strand sections 101, 102, which in turn rest on the second middle clamping element 19. One can also say that the friction head 22 has a Fig. 8A und 8B drawn welding plane S is reached before the middle clamping unit 17 reaches a clamping position. This fact is based on Fig. 6 in which the friction head 22 is already in contact with the second middle clamping element 19, while there is still a distance between the first middle clamping element 18 and the second middle clamping element 19. Until the first middle clamping element 18 has reached the clamping position, the spring element 24 is now increasingly compressed, thereby generating a contact force that depends only on the geometric arrangement of the first middle clamping element 18 and the friction head carrier 21 with the friction head 22 arranged thereon, as well as on the spring constant of the spring element 24. This contact force is thus very reliably reproducible and does not depend, for example, on the clamping force of the middle clamping unit 17 (which acts between its clamping elements 18, 19).

[0039] The first middle clamping element 18 is in turn coupled in a rotationally fixed manner to a crank arm 40, which is coupled via a first coupling rod 41 to a first feeler lever 50. This first feeler lever 50 interacts with a first cam track 55, which is seated in a rotationally fixed manner on the control shaft 6. If the feeler lever 50 is deflected by the cam track 55, it presses the crank arm 40 down via the first coupling rod 41, whereby the first middle clamping element 18 is transferred into the clamping position. The clamping force exerted in this process is in turn controlled by the pretension of a spring element 43 integrated into the first coupling rod 41. As can be seen from the partial sectional view in Fig. 7 As can be seen, the first coupling rod 41 has a first rod part 42 and a second rod part 47 connected thereto. A piston part 44 of the first rod part 42 is partially received in a cylinder part 48 of the second rod part 47. An adjusting sleeve 46 partially surrounds the piston part 44 and is in turn partially arranged within the cylinder part 48. The aforementioned spring element 43 (which thereby forms a disc spring assembly) is preloaded between the adjusting sleeve 46 and an inner flange 49 of the cylinder part 48. On a side opposite the spring element 43, a head section 45 of the piston part 44 bears positively against the inner flange 49. The preload of the spring element 43 can be adjusted by changing the position of the adjusting sleeve 46 relative to the piston element 44.The total length of the coupling rod 41 remains unchanged when the adjusting sleeve is adjusted and changes only by a deflection of the two rod parts 41, 47 relative to each other. When adjusting the preload, it can be taken into account that the clamping force of the first central clamping element 18 is reduced by the contact force of the friction head 22, which means that a correspondingly higher preload must be set to achieve a specific clamping force.

[0040] Fig. 8A und 8B show rear views of the binding device 11, with the viewing plane located in front of the rear clamping unit 60, so that the latter is not visible. The viewing direction is parallel to the welding pivot axis C, which in turn is inclined by 5° relative to the longitudinal axis X toward the vertical axis Z. Fig.8A shows a condition that Fig.2B The front clamping unit 12 is open, while the middle clamping unit 17 is closed. The reaming head carrier 21 is in a welding position in which the reaming head 22 is lowered to the welding plane S. Fig. 8B , however, shows a state in which both the front clamping unit 12 and the middle clamping unit 17 are open, with the second front clamping element 14 also pivoted into the release position. The reaming head carrier 21 is in a passive position in which the reaming head is lifted from the welding plane S.

[0041] The transition between the welding position and the passive position occurs through a pivoting movement through an angle of approximately 42°. The comparatively small pivoting angle is made possible by the fact that the welding pivot axis C is arranged below the welding plane S. As a result, the upward movement of the friction head 22, which lifts it off the welding plane S, is associated with a considerable horizontal movement component. Thus, after just a small pivoting angle, the friction head carrier 21 and the friction head 22 leave a strand path region V in which the binder strand 100, in particular its second strand section 102, runs at least temporarily. This strand path region V must remain free, in particular when feeding the second strand section 102, in order to avoid a collision with the second strand section 102 or with the binding needle 8.Likewise, the friction head carrier 21 and the friction head 22 can be moved from the passive position outside the strand path area V back into the welding position with a comparatively small pivoting movement.

[0042] During the pivoting movement, the belt tension in the friction head drive belt 35 is maintained by a belt tensioner 38, which acts on the friction head drive belt 35. In the welding position, a pulley rotation axis E of the friction head pulley 36 is arranged on one side of a plane F running through the transmission shaft rotation axis D and the welding pivot axis C. When adjusted to the passive position, the pulley rotation axis E is shifted towards plane F and runs through it to the other side. The appropriate arrangement of the pulley rotation axis E relative to plane F ensures that the friction head drive belt 35 remains constantly tensioned without the opposing belt strands touching.

Claims

1. Binding arrangement (10) for a baler (1), which is designed to form a crop bale (90) in a pressing channel (3) and to envelop it using at least one strand-shaped binding agent, the binding arrangement (10) having a plurality of welding units (20) offset from one another with respect to a transverse axis (Y), each of which has an oscillatingly drivable friction head (22) for friction welding two strand portions (101-103) of at least one binding agent strand (100), the binding arrangement (10) having at least one welding motor (25) for driving the friction heads (22), characterized in that the binding arrangement (10) has a transmission (26) for the simultaneous drive connection of a welding motor (25) to a plurality of friction heads (22).

2. Binding arrangement according to claim 1, characterized in that the welding motor (25) is designed as a hydraulic motor.

3. Binding arrangement according to either of the preceding claims, characterized in that the transmission (26) has a distributor arrangement (27) which connects the welding motor (25) to a plurality of transmitting paths (31), each of which is coupled to a friction head (22).

4. Binding arrangement according to any of the preceding claims, characterized in that the friction heads (22) are spaced apart from the welding motor (25) with respect to a longitudinal axis (X), each transmitting path (31) having a transmitting shaft (34) extending at least partially along the longitudinal axis (X).

5. Binding arrangement according to any of the preceding claims, characterized in that the transmitting shaft (34) has a first shaft pulley (32) on the welding-motor side, which cooperates with a drive belt (29, 30) of the distributor arrangement (27).

6. Binding arrangement according to any of the preceding claims, characterized in that the distributor arrangement (27) has a welding-motor drive belt (29) which cooperates with a welding-motor pulley (28) coupled directly to the welding motor (25) and at least one first shaft pulley (32), and at least one shaft drive belt (30), which cooperates with two first shaft pulleys (32) while bypassing the welding-motor pulley (28).

7. Binding arrangement according to any of the preceding claims, characterized in that the transmitting shaft (34) has a second shaft pulley (33) on the friction head side, which acts via a friction head drive belt (35) on a friction head pulley (36) coupled to the friction head (22).

8. Binding arrangement according to any of the preceding claims, characterized in that a friction head carrier (21) carrying the friction head (22) is pivotable about a welding pivot axis (C) between a welding position, in which the friction head (22) is lowered to a welding plane (S) in which it acts on at least one strand portion (101-103), and a passive position, a belt tensioner (38) acting on the friction head drive belt (35), a pulley rotation axis (E) of the friction head pulley (36) being arranged in the welding position on one side of a plane (F) running through a transmitting-shaft rotation axis (D) of the transmitting shaft (34) and the welding pivot axis (C) and being displaced toward the plane (F) when adjusted to the passive position.

9. Binding arrangement according to any of the preceding claims, characterized in that this is designed in such a way that the welding motor (25) is activated before a control shaft (6), via which a deflection of at least one element of the binding arrangement (10) can be controlled during a binding process, is coupled to a drive motor and / or that the welding motor (25) is deactivated depending on a rotation angle of the control shaft (6).

10. Binding arrangement according to the preamble of claim 1 or according to any of the preceding claims, characterized in that each welding unit (20) is assigned a clamping unit (17), having two clamping elements (18, 19) interacting in a clamping position, a friction head carrier (21) carrying the friction head (22) and a clamping element (18, 19) being mounted coaxially so as to be pivotable about a welding pivot axis (C), the friction head carrier (21), during a closing movement of the clamping element (18, 19) that leads to the clamping position, being guidable via an intermediate first spring element (24) in such a way that it leads the clamping element (18, 19).

11. Binding arrangement according to any of the preceding claims, characterized in that the clamping element (18, 19) is coupled to a positively guided drive element (50) via an intermediate second spring element (43).

12. Binding arrangement according to any of the preceding claims, characterized in that the drive element is a feeler lever (50, 51) which cooperates with a curved track (55, 56, 57) arranged on the control shaft (6) and which cooperates via a coupling rod (41, 52, 53, 54) with a crank arm (40) connected to the clamping element for conjoint rotation, the second spring element (43) being arranged between the feeler lever (50, 51) and the crank arm (40).

13. Binding arrangement according to any of the preceding claims, characterized in that the second spring element (43) is arranged between a first rod part (42) of the coupling rod (41, 52, 53, 54) which is connected to the crank arm (40) and a second rod part (47) which is deflectable relative thereto and connected to the feeler lever (50, 51).

14. Binding arrangement according to any of the preceding claims, characterized in that the welding pivot axis (C) is arranged below the welding plane (S).

15. Baler (1) which is designed to form a crop bale (90) in a pressing channel (3) and to envelop it using at least one strand-shaped binding agent, comprising a binding arrangement (10) according to any of the preceding claims.