Abstract:
A large round baler is equipped with a device for wrapping a bale formed in the baling chamber of the baler with a web of plastic sheeting or net wrapping medium. A supply roll of the wrapping medium is located in a box mounted forward of the baling chamber for movement along a fore-and-aft extending guide rail between a standby position, wherein a free end of the wrapping medium is supported by a guide surface at a location spaced forward of the baling chamber, and a wrapping position, wherein the free end of the wrapping medium is located for being grabbed by rotating rollers and/or the formed bale so that a length of the wrapping medium is pulled from the supply roll as it is wrapped about the bale. A power operated brake operates on the supply roll so as to provide a constant tension in the wrapping medium during wrapping operation.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device for wrapping a round bale with a wrapping medium and more specifically relates to a device for handling a supply roll of wrapping medium 
     BACKGROUND OF THE INVENTION 
     DE-U1-82 21 610 discloses a large round baler equipped with a netting wrapping apparatus including a container for receiving a netting roll, a brake, a pair of rollers and a cutting device. The container is located on top of the round bale press and receives a supply roll of netting material, with the roll lying against the walls of the container during unwrapping. The brake includes a swiveling yoke, with a crossways-running rod that is pressed by means of a spring onto the entire circumference of the roll. The rollers run opposite one another and can be powered to pull the netting off of the roll and lead it to a baling chamber, and to tension it so that it lies taut around the bale. The wrapped length of netting can be separated from the roll by a cutting device which operates at the end of the wrapping process and works upon the taut netting. 
     WO-A1-9705767 discloses a large round baler with a netting or sheeting wrapping apparatus, which enables the free ends of the netting or sheeting to be brought into engagement with the harvested matter and thus to be wrapped around the bale, that has a vertically adjustable netting or sheeting wrapping apparatus. The unwound part of the netting or sheeting is separated from the roll by braking the roll or actually bringing it to a stop, so that the netting or sheeting tears off. How a possible brake could look or might be attached is not disclosed. 
     According to U.S. Pat. No. 4,956,968 a large round baler is equipped with a netting wrapping apparatus that brings the ends of the netting into the area between the press elements and the round bales by means of a swiveling feed arm. No brake operates on the netting roll itself. 
     This state of the art yields different types of brakes—those, for one, that are supposed to prevent the wrapping medium on the roll from unwinding, so that the wrapping medium does not build up, as well as those that delay movement of the wrapping medium, so that it is wrapped firmly around the bale and tears off or can be cut easily. 
     The problem, on which this invention is based, is perceived to be that the aforementioned brakes/rollers, and the balers equipped with them, are relatively complicated. 
     SUMMARY OF THE INVENTION 
     According to the present invention, there is provided an improved manner of handling a supply roll of bale wrapping medium on a baler equipped with a bale wrapping arrangement. 
     An object of the invention is to provide a wrapping arrangement for a large round baler including a motor for applying a braking force to a supply roll of wrapping medium during the time that a length of wrapping material is being pulled from the supply roll by the action of a rotating bale located in the baling chamber. 
     A more specific object of the invention is to provide a wrapping arrangement, as set forth in the previous object, wherein the motor is controlled so as to vary the braking force, and/or duration thereof, applied to a wrapping material supply roll in accordance with atmospheric conditions and/or control signals generated by sensors measuring the quantity of netting or sheeting pulled off the supply roll, the roll-off speed, and the like. The brake includes a contact element mounted at the end of a pivotal arm and, since the position of the arm is indicative of the roll diameter, the quantity of wrapping medium remaining on the roll is a function of arm position and this can be sensed. Also, the contact element is the form of a roller so that its rotation is indicative of the amount of wrapping material pulled off the supply roll, and this rotation can be sensed. 
     Another broad object of the invention is to provide a wrapping arrangement which, without the need for driven wrapping medium feed rolls, selectively places the free end of the wrapping medium in a position to be grabbed and pulled off the supply roll by the bale-forming elements and/or the formed bale. 
     A further specific object of the invention is to provide a wrapping arrangement wherein the container for the supply roll and a guide for the wrapping material may be selectively moved between a standby position, wherein the guide holds a free end of the wrapping medium at a location spaced from the baling chamber, and a dispensing position, wherein the free end of the wrapping medium is disposed for being grabbed by harvested matter entering the baling chamber and/or by the bale forming elements and/or the formed bale. 
     These and other objects of the invention will become apparent from a reading of the ensuing description together with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic, right side view of a large round baler equipped with a mechanism for wrapping the bale with sheeting or netting material. 
     FIG. 2 is an enlarged view of the wrapping device shown located in its non-operating or standby condition. 
     FIG. 3 is a view like FIG. 2 but showing the wrapping device in an operating or wrapping condition. 
     FIG. 4 is a perspective view showing the braking arrangement for the roll of wrapping material. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, there is shown a large round baler  10  equipped with a wrapping device  12  for wrapping bales formed by the baler  10 . The baler  10  includes a frame or chassis  14  supported on a pair of ground wheels  16  and having a tongue  18  adapted for being hitched to a tractor. A baling chamber  20  is formed by a plurality of rollers  22  arranged in a circle. A harvested matter intake  24  is located at about the five o&#39;clock position for receiving harvested matter delivered thereto by the action of a pick-up  30  and a tined rotor which cooperates with a cutter  32 . The frame  14  is subdivided into a vertical swinging rear part  26  and a front housing part  28 , in each of which approximately half of the rollers  22  are located. 
     Referring now to FIGS. 2 and 3, it can be seen that the wrapping device  12  includes a housing or container  34 , a guide surface  36 , a brake  38 , an adjusting device  40  and a cutting device  42 . 
     The wrapping device  12  is located in the upper front area of the front housing part  28  and serves to keep available a wrapping medium supply roll  44  from which a length of wrapping medium  46  is shown extending from the bottom of the roll. The length of wrapping medium  46  is located for being conveyed into the baling chamber  20  for being wrapped around a bale formed therein. The roll  44 , and hence the wrapping medium  46  advantageously extends over the entire width of the baling chamber  20 , or even wider than that, if it is desired to wrap the medium over the edges of the bale ends. 
     The housing  34  is configured as a sheet metal box that is open in the back and on the top, and includes a floor  48 , a front wall  50 , and opposite side walls  52 . The housing  34  extends between opposite side walls  54  of the baler front housing part  28 , and is set on horizontal, fore-and-aft extending guide rails  56  that allow the housing  34  to be shifted therealong, toward and away from the baling chamber  20 . The roll of wrapping medium  44  is located in the housing  34 . The roll  44  is shown in a position wherein it rolls off the floor  48  and wall  50 . Alternatively, the roll could be set so that it could be turned on its axle, where the axle is held fast between the side walls  52  or is moveable in the direction of the front wall  50 . 
     Guide surface  36  is configured as a channel of sheet metal, synthetic material, bars or something similar, and extends from floor  48  toward rollers  22 . The side areas of guide surface  36  are partly bent upward, to form the channel shape. The wrapping medium  46  slides along the top of guide surface  36  from the roll  44  to the end of guide surface  36 , and hence to the gap between two neighboring rollers  22 . A covering surface could also be provided over guide surface  36  that would prevent dirt, which hinders the wrapping medium&#39;s movement, from settling on guide surface  36 . 
     Brake  38  is located in the housing  34  and features an adjusting device  58 , a contact element  60  and a motor  62 . The brake  38  has the task of holding back the movement of the wrapping medium  46 , so that it is laid taut onto the entire circumference of a round bale. In addition, the tension is also kept up so that the wrapping medium  46  can be reliably cut or separated from the roll  44 . Brake  38  is configured so that it continues to generate the same tension in the wrapping medium  46  despite the diminishing diameter of the roll  44 . Brake  38  is connected to the housing  34  so that it moves together with it, which means that it maintains the same position with reference to the receiver  44 . 
     As can best be seen in FIG. 4, brake  38  includes, in the embodiment example presented, a rectangle-shaped tubular frame having opposite sides defined by arms  64  having respective front ends joined to opposite ends of a tubular cross member  66 , and having respective rear ends joined to opposite ends of a rear cross member having its opposite ends each mounted to a bearing  68  located in the opposite side walls  52  so as to define a horizontal, transverse pivot axis about which the frame is swingable. Provided on the cross member  66  are two contact elements  60  configured as sleeves and that are arranged so that they can be rotated, such that heat build-up between the elements  60  and the member  66  and wrapping medium  46  is avoided. Contact elements  60  are, for example, made of a wear-resistant synthetic material and are equipped with a textured surface. Contact elements  60  are each located in the side areas of the cross link  66 , but a single element extending the entire length of the cross member  66  could be used as well. 
     An extensible and retractable motor  62  lies between a second bearing  70  on the side walls  52 , or between a shaft extending between the side walls, and the cross link  66 , and serves to hold the contact elements  60  in steady, although appropriately variable, contact with the entire circumference of the roll  44 . Motor  62  is, in this embodiment example, configured as an extensible and retractable hydraulic cylinder. To this belongs a controlling or regulating apparatus, not shown, that can function in various ways, but which, in any case, adapts the tension of the wrapping medium  46  to meet the respective requirements. Motor  62  grasps cross member  66  at a location centered between the contact elements  60 , while bearings  68 ,  70  and the engaging point of the motor  62  with the cross member  66  form a triangle. 
     Adjusting device  40  includes a servomotor  72  with a regulating system (not shown) and rails, on which the housing  34  rests. Adjusting device  40  has the task of moving the housing  34  and the guide surface  36  toward or away from the baling chamber  20 , as shown in FIGS. 2 and 3. In this way, the end of guide surface  36  arrives at the gap between the rollers  22  and, with the end of the wrapping medium  46  hanging down, the wrapping medium is brought into the baling chamber  20  where it is caught between the entire circumference of the just-formed round bale and the bale-forming rollers  22 , which carry the wrapping medium  46  along. FIGS. 2 and 3 indicate that the apparatus  12  is moved toward the baling chamber  20  when the wrapping process is initiated, and is moved away from it when the wrapping process ends. Instead of being guided on the rails  56 , as shown, other methods could be suitable for the adjustment, for example, controlling rods, rollers and channels, etc. While the rails  56  are essentially configured horizontally in the drawing, they could be inclined or follow a defined curve. In any case, however, it is only essential that the wrapping medium  46  be reliably brought into the gap between the rollers  22  and that the guide surface  36  be able to be retracted for the separation process. 
     Cutting device  42  is configured in the manner of a pair of scissors, the blades of which are located on the outer portion of a wedge area located between the rollers  22 . Depending on the possible adjustment methods of the apparatus  12 , cutting device  42  can also be configured differently, or it can be located at a greater distance from the rollers  22 . Cutting device  42  is configured so that it allows the passage of the end of the wrapping medium  46  that hags down and perhaps also at the end of guide surface  36 . Cutting device  42  will be activated automatically; after the end of the wrapping process, in the course of which the wrapping medium  46  is cut so that a sufficiently long overhang is left on the end of the guide surface  36 . According to an alternative embodiment, not shown, cutting device  42  has an immobile upper or lower toothed separating ridge. Wrapping medium  46  is then applied to this separating ridge and pulls the wrapping medium  46  tightly across it. This can be accomplished through appropriate guidance by means of the rails  56 , which for example, would not run horizontal, but rather would inline or ascend in this case. 
     Summarizing, the following function is evident: 
     The starting point is the condition shown in FIGS. 1 and 2, in which no wrapping of a round bale occurs. The end of the wrapping medium  46 , which is hanging down, does not come into engagement with, or into contact with; the round bale. Motor  62  is applied in such a way as to hold the roll  44  of wrapping medium  46  motionless in the housing  34 . Servomotor  72  is in its extended condition. 
     To induce the wrapping process, the servomotor  72  is retracted and with it the housing  34  with the guide surface  36  is moved toward the baling chamber  20 , so that the end of the wrapping medium  46 , and perhaps also the free end of the guide surface  36 , can enter into the gap between adjacent ones of the rollers  22 . At this time, the brake  38  exerts little or no pressure. After movement is complete, as shown in FIG. 3, the end of the wrapping medium  46  lies on the round bale and is pulled into the baling chamber  20 . While the wrapping medium  46  is being pulled from the roll  44 , the brake  38  exerts pressure on the roll  44 , so that wrapping medium  46  is put under tension. By means of sensors, which are riot shown and which track the position of the pivotable arms  64  or the compressive force of the motor  62 , changes in adjusting device  58  are achieved that generate even tension in the wrapping medium  46 . 
     As soon as the wrapping process is finished, housing  34  with guide surface  36  is retracted far enough that only wrapping medium  46  is still in the cutting device  42 . Next, cutting device  42  is activated, so that the free end of the wrapping medium  46  hangs down over the end of the guide surface  36  and is ready for the start of the next wrapping process. Finally, housing  34  and guide surface  36  are moved back all the way into the position shown in FIG.  2 . 
     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.