Abstract:
A round baler is provided for producing bales. The baler has a bale-forming chamber, at least one roller that is driven and that defines a part of an extent of the bale-forming chamber and that is mounted on a moving holder. Continuous, flexible bale forming elements are driven and define another part of the extent of the bale-forming chamber. The bale forming elements contact a first rotating body and a second rotating body, of which the first rotating body is mounted on the holder. It is proposed that the second rotating body is coupled with the holder with respect to motion by a drive connection, so that both move together with the growing bale.

Description:
FIELD OF THE INVENTION 
     The invention relates to a round baler for producing bales, wherein the round baler has a bale-forming chamber, at least one drivable roller that defines a part of the periphery of the bale-forming chamber and that is mounted on a moving holder, and a drivable, continuous, flexible bale forming means that defines another part of the periphery of the bale-forming chamber and that contacts a first rotating body and a second rotating body, wherein the first rotating body is mounted on the holder. 
     BACKGROUND OF THE INVENTION 
     Balers are used in agriculture to take up harvested material from a field and form it into a bale. In addition to rectangular balers in which a plunger cyclically compresses the harvested material in a baling chamber, round balers are common in which the taken-up harvested material is introduced into a cylindrical bale-forming chamber and there set into rotation by driven elements. In the case of round balers, embodiments with a fixed bale size are known in which the periphery of the bale-forming chamber is defined by rollers or rotating bodies connected rigidly to the frame of the baler, and embodiments with variable bale size in which a flexible bale forming means in the form of belts or chains equipped with catch elements define the periphery of the bale-forming chamber. The bale forming means are biased by means of a hydraulic cylinder that acts with a force on an arm carrying a roller on which the bale forming means contacts, so that the size of the bale-forming chamber grows with the taken-up quantity of material. When a specified size or density of the bale is reached, the bale is typically wound with twine, net or film and then a rear door is opened and the bale is ejected from the bale-forming chamber. 
     U.S. Pat. No. 5,367,865 A1 describes a round baler in which the bale-forming chamber is defined toward the front by several rollers that can be driven to rotate and that are mounted next to one another on a holder that can pivot about the rotational axis of the lowest roller. Toward the back, the bale-forming chamber is defined by a belt that revolves around several rollers. One of these rollers is mounted on the top of the holder and is not driven. Two other rollers wrapped around by belts are mounted on a first arm that can pivot about an axis and that is coupled with a second arm at which another end of the frame of the round baler attaches to a connected hydraulic cylinder used for providing a defined tensile stress in the belt. When the harvested material collects in the bale-forming chamber, the holder pivots with the rollers gradually upward about the rotational axis of the lower roller. At the same time, the belt in the rear area of the baler forms a growing loop. Because the belt is also wrapped around the roller mounted on the holder, the holder and the belt move outward in a coordinated way. Because the belt also revolves around rollers that are mounted on a rear door, the pivoting region of the first arm is sufficient for achieving a sufficient tension also when ejecting the bale. 
     U.S. Pat. No. 6,094,900 A1 shows a round baler wherein the bale-forming chamber is likewise defined toward the front by rollers mounted on a pivoting holder and toward the back by a belt. The holder is supported by a hydraulic cylinder relative to the frame of the baler and is furthermore extended toward the back and upward and carries, on its rear, upper end, two rollers around which the belt is wrapped. The hydraulic cylinder thus supports the holder on the frame and also defines the tensile stress of the belt. The belt also revolves around rollers mounted on a rear door, so that the pivoting region of the holder is adequate to achieve sufficient tension of the belt also when ejecting the bale. 
     In U.S. Pat. No. 7,165,491 B2, another round baler is described wherein the bale-forming chamber is defined only by a single bale forming means in the form of belts. The belts revolve around several deflection rollers of which a few are mounted on a first, pivoting arm and others are mounted on a second, pivoting arm. The arms are tensioned against each other by a hydraulic cylinder used for generating the desired tension in the bale forming means. The bale forming means also revolves around two deflection rollers mounted on a pivoting carrier on the bottom side of the baler. The carrier maybe pivoted about its axis extending parallel to the axis of the bale-forming chamber rearward and upward into a bale-ejection position. The two arms allow the belts to also be held sufficiently taut in the bale-ejection position of the carrier. 
     EP 1 308 078 A1 describes a round baler of the type mentioned above wherein the bale-forming chamber is defined toward the front by rollers that can be driven, of which one is mounted on a pivoting holder, and otherwise by a single bale forming means in the form of belts. The bale forming means revolves, among other things, around a deflection roller connected to the holder, around a deflection roller mounted on a tensioning arm, and around two deflection rollers mounted on a pivoting carrier on the bottom of the baler. The carrier can be pivoted about its axis extending parallel to the axis of the bale-forming chamber rearward and upward into a bale-ejection position. Here, a relatively long tension arm is required, in order to maintain the tension of the belt also in the bale-ejection position of the carrier. 
     The problem forming the basis of the invention is thus seen in providing a round baler having a mechanism that is improved relative to the state of the art for generating and maintaining the tension of the bale forming means. 
     SUMMARY OF THE INVENTION 
     Accordingly, a round baler is provided that comprises a cylindrical bale-forming chamber whose periphery is defined by at least one roller that can be driven and by a flexible bale forming means. The roller is mounted on a moving holder, so that the holder and the roller can move outward with the growing size of a resulting bale, be it on a linear path or a curved path. The bale forming means that may involve, for example, a single, sufficiently wide belt or several belts or one or more chains with catches mounted on these chains, contacts a first rotating body and a second rotating body and wraps around both at least partially. The first rotating body is connected to the holder and moves with it when the bale grows. The second rotating body can likewise move relative to the frame of the round baler and is coupled with the holder by a drive connection with respect to motion. When the holder moves outward with a growing size of the bale, the second rotating body is thus also forced to move by the drive connection, so that its position can be adapted in a suitable way to the growing size of the bale. 
     In one embodiment of the invention, the tension of the bale forming means is defined by tension-generating means that can interact with another (third) round body that can move relative to the frame of the round baler and around which the bale forming means wrap at least partially. For simplification, however, it is preferable to insert the tension-generating means in the bale forming means in the drive train between the holder and the second rotating body for generating a tensile stress. Consequently, one end of the tension-generating means moves with the holder and the other end of the tension-generating means moves with the second rotating body. In this way, a defined tensile stress is simultaneously generated in the bale forming means and a defined force is exerted on the holder, so that the bale can grow in a controlled way. 
     The tension-generating means can have a spring and/or a hydraulic cylinder. The latter can be connected to a pressure-limiting valve, in order to achieve a defined pressure in the hydraulic cylinder and thus a desired tension in the bale forming means. In this regard, refer to the state of the art according to U.S. Pat. No. 6,094,900 A1 that is incorporated herein by reference. 
     In an embodiment of the invention, the holder is connected to the frame of the round baler so that it can pivot about an axis extending parallel to the axis of the bale-forming chamber, i.e., horizontal and perpendicular relative to the forward direction of the round baler, and indeed advantageously on its front, lower end. The drive connection may comprise a first arm that is mounted on the holder and that extends perpendicular to the holder, i.e. in the case of an empty bale-forming chamber and a holder then extending upward and backward at an angle from the axis is located above and possibly in the forward direction of the round baler in front of the holder. In addition, the drive connection may have a second arm on which the second rotating body is supported. The second arm is advantageously connected on the frame of the round baler so that it can pivot about an axis extending parallel to the axis of the bale-forming chamber. This axis is located in the forward direction of the round baler in front of the second rotating body. A lever arm may be connected rigidly to the second arm. The tension-generating means is then mounted advantageously between the first arm and the lever arm, wherein it may be hinged in a pivoting way with two axes extending parallel to the axis of the bale-forming chamber. 
     Additional belt sections that also contact rotating bodies supported rigidly on the frame of the round baler can connect to the belt section of the bale forming means located between the first and second rotating bodies. Furthermore, the bale forming means may pass between two additional rotating bodies mounted on the holder. One of these rotating bodies can prevent undesired contact of the bale forming means with one of the rollers of the holder, while the other rotating body supports the bale forming means in the bale-ejection position. 
     The present invention can be used on round balers with a rear door, as described in U.S. Pat. No. 5,367,865 A1 or U.S. Pat. No. 6,094,900 A1, i.e. a rear half of the housing of the round baler that can swing open and comprises, on its bottom, a rotating body around which the bale forming means revolves. Such a rear door causes, in its bale-ejection position, sufficient lift and tightness of the bale forming means that allows a problem-free ejection of the bale. The present invention may also advantageously use round balers with a pivoting carrier that is hinged on the frame of the bale press about an axis extending parallel to the axis of the bale-forming chamber and that may be moved by an actuator between a bale-forming position in which it is located in the lower, rearward region of the round baler and a raised bale-ejection position pivoted about the axis. The carrier supports, at a distance from the axis on its outside, two rotating bodies on which the bale forming means contacts. The drive connection between the holder and the second rotating body, in particular, the tension-generating means, allows the second rotating body to be brought into a position in which it keeps the bale forming means sufficiently taut even in the case of a carrier brought into the bale-ejection position, in order to be able to eject the bales. When the carrier is located in the bale-ejection position, the holder can be locked in its position last assumed during the formation of the bale or a farthest possible raised position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The embodiments of the invention are described in more detail below with reference to the accompanying drawing figures wherein: 
         FIG. 1  is a schematic side view of a round baler with empty bale-forming chamber; 
         FIG. 2  is a side view of the round baler from  FIG. 1  with partially filled bale-forming chamber; 
         FIG. 3  is a side view of the round baler from  FIG. 1  with completely filled bale-forming chamber; 
         FIG. 4  is a side view of the round baler from  FIG. 1  during the ejection of the bale; and, 
         FIG. 5  is a hydraulic diagram of the round baler. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In  FIG. 1 , a baler  10  is shown in a schematic side view. The baler  10  comprises a frame  12  that is supported by wheels  14  on the ground and on whose front a tow bar  16  is attached that can be coupled by means of a front towing eye  18  onto a coupling jaw of a tractor (not shown). The baler  10  is covered and enclosed from the outside by a housing  20  whose top and rear, however, are open, as will be explained later with reference to  FIGS. 2 and 4 . In the following, directional specifications, such as front, rear, top, and bottom, refer to the forward direction V that runs from right to left in  FIGS. 1-4 . 
     Within the baler  10 , a bale-forming chamber  26  is defined downward by a roller  28  that can be driven and in which an opening  30  connects toward the front through which harvested material picked up from the ground by means of a pick-up device  32  and fed backward and upward by a connecting transfer rotor  34  is introduced into the bale-forming chamber  26 . At the side, the bale-forming chamber is defined by front walls  22  and rear walls  24 , wherein the front walls  22  are advantageously mounted rigidly on the frame  12 , while the rear walls  24  can be moved advantageously slightly outward by suitable actuators for reducing the friction during the ejection of a bale. 
     Above and in front of the opening  30  there are two additional rollers  36 ,  38  that can be driven like the roller  28  and that are supported rigidly on the frame  12 . Above the upper roller  38  there is a roller  40  about whose rotational axis  42  an essentially circular-arc-shaped holder  44  is supported so that it can rotate. The holder  44  carries an additional four driven rollers  46 ,  48 ,  50 , and  52  and three free-running rotating bodies  54 ,  78 ,  90 . 
     A drive train driven by the tractor drives, by way of a belt disk  56 , a belt  58 , and a belt disk  60 , the roller  40  and, by way of additional belt drives  62 ,  64 ,  66  and  68 , the rollers  46 ,  48 ,  50 , and  52 . In addition, the drive train driven by the tractor drives the rollers  28 ,  36 , and  38 , as well as the pick-up device  32  and the transfer rotor  34 , and, by means of a belt  70 , a belt disk  72  for the drive of a bale forming means drive rotating body  74 . 
     Toward the back, the bale-forming chamber  26  is defined by flexible, continuous bale forming means  76  that revolve around the bale forming means drive rotating body  74 , the rotating bodies  54 ,  78 , and  90 , as well as around rotating bodies  80 ,  82 ,  84 ,  86 , and  88 . The flexible bale forming means  76  can involve one or more belts or one or more chains with catches attached to them. If one or more belts are used, then the rotating bodies  54 ,  74 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 , and  90  are constructed as rollers or cylinders, and if chains with catches are used as the bale forming means, then they are constructed as chain pinions sitting on a shaft or axle. The rotating bodies  78  and  90  are mounted, like the rotating body  54 , on the holder  44  so as to move with it about the rotational axis  42 . All of the rollers and rotating bodies  28 ,  36 ,  38 ,  40 ,  46 ,  48 ,  50 ,  52 ,  74 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 , and  90  extend horizontally and perpendicular relative to the forward direction V, are supported so that they can rotate about their axes, and extend across the width of the bale-forming chamber  26 . The rotating bodies  80  and  82  located in the lower region of the flexible bale forming means  76  are mounted on a triangular carrier  92  that is hinged at its upper tip  94  on the frame  12  so that it can pivot about an axis extending horizontal and perpendicular relative to the forward direction and can be moved about this axis by at least one external-force-activated actuator  96 . The carrier  92  also holds another rotating body  98  underneath the bale forming means  76 . The rotating bodies  74  and  84  can rotate but are otherwise mounted fixed on the frame  12 . 
     On the holder  44 , a first arm  100  is mounted that extends upward and forward perpendicular to the connection line between the rollers  40  and  46  and on whose outer end away from the holder, tension-generating means  102  are hinged in the form of a hydraulic cylinder that can pivot about an axis  104  extending horizontally and perpendicular to the forward direction and consequently parallel to the axis of the bale-forming chamber  26 . The moving output  106  of the tension-generating means  102  is hinged on a lever arm  110  so that it can pivot about an axis  108  extending parallel to the axis of the bale-forming chamber  26 , wherein, on its side, this lever arm is hinged on the frame  12  so that it can pivot about an axis  112  extending parallel to the axis of the bale-forming chamber  26  and is connected rigidly to a second arm  114  that carries, on its outer end, the rotating bodies  88  and  86  arranged one after the other. The arms  100  and  114 , the lever arm  110 , and the tension-generating means  102  form a drive connection between the holder  44  and the rotating bodies  88  and  86 , with this connection forcibly coupling the position of the rotating bodies  88 ,  86  with the position of the holder  44 . With the growing bale in the bale-forming chamber  26 , and thus with the outward moving holder  44 , the rotating bodies  88 ,  86  are consequently forcibly tracked and provide the desired tension in the bale forming means  76 . The tension-generating means  102  is set by a suitable valve controller under pressure so that the desired tension of the bale forming means  76  is generated. This valve controller advantageously comprises a pressure-limiting valve  154  that maintains the desired pressure in the plunger rod chamber of the hydraulic cylinder and the desired tension in the bale forming means  76 . A suitable switch is shown in  FIG. 5 . 
     Starting from the bale forming means drive rotating body  74 , the bale forming means  76  extends around the rotating body  90  supported on the holder  44 , around the rotating bodies  88 ,  86  supported on the second arm  114 , around the frame-fixed rotating bodies  84 , around the rotating bodies  82 ,  80  supported on the carrier  92 , and around the rotating body  78  that is supported on the holder  44  and that is used to keep the bale forming means  76  away from the roller  52 . The function of the rotating bodies  54  and  98  will be made clear later with reference to  FIGS. 2 and 4 . In bale-forming mode, the bale forming means drive rotating bodies  74  rotate in the clockwise direction, so that the belt section of the bale forming means  76  defining the bale-forming chamber  26  toward the back is moved upward. The rollers  28 ,  36 ,  38 ,  40 ,  46 ,  48 ,  52  likewise rotate in the clockwise direction, so that the harvested material introduced into the bale-forming chamber  26  travels on a spiral path in the counterclockwise direction. However, opposite rotational directions would also be conceivable. In the case of an empty bale-forming chamber  26 , the carrier  44  lies on a lower stop (not shown). 
     According to all of the preceding, the following function of the round baler  10  is given. In  FIG. 1 , the bale-forming chamber  26  is empty and, in harvesting mode, the round baler  10  is pulled across a field by the tractor (not shown), wherein it picks up, from the field, harvested material laid in a swath by means of the pick-up device  32  and introduces it via the transfer rotor  34  into the bale-forming chamber  26  in which it travels on the mentioned, spiral path by means of the bale forming means  76  moving upward and the rollers  28 ,  36 ,  38 ,  40 ,  46 ,  48  and  52  rotating in the counterclockwise direction. 
     Thus, a gradually growing bale  116  is created, as shown in  FIG. 2 . It can be seen there that the holder  44  is pivoted upward due to the bale  116  forming in the bale-forming chamber  26  by some multiple of 10° about the axis  42  in the counterclockwise direction, and with it the rotating bodies  54 ,  78 ,  90 . The belt sections  118  and  112  of the bale forming means  76  between the rotating body  90  and the bale forming means drive rotating body  74  on one side and the rotating body  88  on the other side relative to the empty bale-forming chamber  26  shown in  FIG. 1  are shortened, because the rotating body  90  is pivoted upward with the holder  44 . Simultaneously, the rotating body  88  is also pivoted upward with the second arm  114  about the axis  112 , caused by the motion of the first arm  100  and a stretching motion of the output  106  of the tension-generating means  102  leading in the opposite direction, wherein this motion is produced by the pressure acting in the plunger-rod chamber of the tension-generating means and limited by the pressure-limiting valve  154 . The length of the bale forming means  76 , becoming free during the movements of the rotating bodies  86  and  90 , wraps around the rear part of the bale  116  and bulges out toward the back. Accordingly, the bale forming means  76  wraps around the rotating body  54  partially, because the latter forms an upper, rear limit of the region of the bale forming means  76  enclosing the bale-forming chamber  26 . The housing  20  is open at the top, so that the rotating bodies  88 ,  86  can move upward out from the housing. 
     In the situation shown in  FIG. 3 , the bale  116  has grown to the maximum possible size and the carrier  44  contacts an upper stop (not shown). Relative to the position in  FIG. 2 , the carrier  44  is pivoted upward even farther about the axis  42 , so that the rotating bodies  54  and  90  (and the now non-functioning rotating body  78 ) are likewise moved even farther upward. Due to the prevailing pressure ratios in the tension-generating means  102 , their output  106  is moved even farther outward, so that the rotating bodies  88 ,  86  are pivoted downward again about the axis  112  relative to the situation in  FIG. 2 . The belt sections  118 ,  120  are therefore shortened again relative to  FIG. 2  and their missing length wraps around the rear part of the bale  116 . A signal to stop is output to the operator of the tractor unit or to its drive controller, so that no more harvested material comes into the bale-forming chamber  26 . In addition, the bale  116  can be wound with a winding material (twine, netting, film, etc.). The drive for the rollers and rotating bodies  28 ,  36 ,  38 ,  40 ,  46 ,  48 ,  50 ,  52 ,  74 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88  and  90  is then stopped and optionally the rear wall  24  is moved outward laterally. Then the bale  116  is ready to be ejected. 
     In  FIG. 4 , the carrier  92  has been moved by the actuator  96  about the axis  94  backward and upward into the bale-ejection position and the bale  116  has been ejected from the bale-forming chamber  26 . The carrier  44  is still located in the position from  FIG. 3  and can be held there by a locking device  122 . Because the carrier  92  is moved into the bale-ejection position, the bale  116  can roll out due to the force of gravity from the bale-forming chamber  26  onto the ground, advantageously on a chute (not shown). In order to take up the length of the bale forming means  76  becoming free during the pivoting of the carrier  92  about the axis  94 , the output  106  of the tension-generating means  102  is retracted again by suitable loading, which leads to the result that the rotating bodies  86 ,  88  on the second arm  114  are rotated far forward and upward about the axis  112  and are located outside of the housing  22  above the round baler  10  and their front and the belt section  120  and also the belt section  124  have become rather long between the rotating body  86  and the rotating body  84 . Here, the rear or upper rotating body  86  still allows sufficient take-up of a length of the bale forming means  76 . In this position, the rotating body  98  of the carrier  92  forms, with the rotating bodies  80  and  84 , a double loop of the bale forming means  76 , with this loop also taking up a part of the length of the bale forming means  76  becoming free during the upward pivoting of the carrier  92  into the bale-ejection position. After the ejection of the bale  116 , the locking device  122  can be released and the carrier  92  can be pivoted by the actuator  96  back into the bale-forming position, as shown in  FIGS. 1-3 . 
     It should also be noted that a controller  126  controls the functioning of the round baler  10  and can drive, in particular, the actuator  96  and the tension-generating means  102  by means of suitable valves, as shown in  FIG. 5 . In addition, the controller  126  may be connected to a sensor (not shown) for the size and/or density of the bale  116  and may automatically trigger the winding process as well as the stopping of the tractor unit when the bale  116  reaches a selectable or permanently specified size (which may be smaller than the maximum size of the bale) and may control the functions described above for the actuator  96 , the locking device  122 , and the tension-generating means  102 . In the case of bale sizes smaller than the maximum bale size, the locking device  122  can lock the carrier  44  in the last assumed position or move it into the highest possible position, as shown in  FIGS. 3 and 4 . 
     In  FIG. 5 , a hydraulic diagram of the round baler  10  is shown. The pressure provided by a pump  130  arranged onboard the tractor unit is transferred to the valve arrangement  134  of the controller  126  via a control valve  132  that is controlled by the operator of the tractor unit or automatically by the controller  126  and that is located on board the round baler  10 . A second connection of the control valve  132  is connected to a tank  136 . The two chambers of the actuators  96  provided on both sides of the round baler  10  and constructed as hydraulic cylinders are each connected directly to one of the output lines A, B of the control valve  132 . The plunger chamber of a hydraulic cylinder of the locking device  122  is also connected directly to one of the output lines A of the control valve  132 . The plunger-rod chambers of the tension-generating means  102  provided on both sides of the round baler  10  and also constructed as hydraulic cylinders are connected via an electromagnetically controlled valve  138  and a sieve valve  140  to one of the output lines B of the control valve  132 . The sieve valve  140  is used for maintaining the pressure in the tension-generating means  102 . The plunger chambers of the tension-generating means  102  are connected to a line  142  that is connected via sieve valves  144 ,  146  to the output lines A, B of the control valve  132 , which each allow flow into the plunger chambers during stretching of the tension-generating means  102  and flow out from the plunger chambers during contraction. In the open state, the valve  138  allows a control of the pressure in the plunger-rod chamber of the tension-generating means  102  by means of a pressure-limiting valve  148 , in order to generate a soft bale core, and, in the closed state of the valve  138 , an overflow valve  150  contained therein becomes active, which opens by means of the actuator  96  when the carrier  92  is raised, in order to contract the tension-generating means  102 . A pilot valve  152  connected parallel to the pressure-limiting valve  148  between the inlet of the valve  138  and the line  142  allows the free movement of the tension-generating means  102  in the case of stretched actuators  96 . Another pilot valve  154  is arranged between the output of the valve  150  and the line  142  and limits the pressure in the plunger-rod chamber of the tension-generating means and defines the density of the bale. The shown hydraulic circuit allows the previously described functions of the round baler  10 . 
     The round baler  10  according to the invention with the drive connection between the holder  44  and the rotating bodies  86 ,  88  has the advantages that, despite the shortest possible bale forming means  76 , a relatively large bale  116  can be generated, that the rotating bodies  86 ,  88  at empty bale-forming chamber  26  remain within the outline of the housing  22  and the bale forming means  76  are still held taut also in the case of the carrier  92  brought into the bale-ejection position. Another advantage of the round baler  10  described here lies in that parts of round balers that are already known can be used, like the holder  44  with the rollers  40 ,  46 ,  48 ,  50 ,  52  or the carrier  92 . 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.