Abstract:
A large round baler is provided with a twine wrapping arrangement including a twine dispensing arm, a twine separating or severing device located between the dispensing arm and a baling chamber and a twine brake located between the separating device and the baling chamber. The twine brake is constructed of spring elements that are yieldably biased together, preferably in the form of a coil tension spring having a guide finger for guiding twine into a nip formed between the finger and a first coil of the spring, this nip receiving a length of twine extending between the dispensing arm and a bale being wrapped with the twine, with the twine becoming wedged between adjacent coils of the spring. As an alternative construction, a stack of Belleville springs are held together by bolt and nut assembly, with the nip being defined between adjacent springs.

Description:
FIELD OF THE INVENTION  
         [0001]    The invention concerns a large round baler with a baling chamber, a binding arm, a separating arrangement and a twine brake.  
         BACKGROUND OF THE INVENTION  
         [0002]    U.S. Pat. No. 4,627,340 discloses a large round baler with a binding arm, a twine brake, a separating arrangement and a twine retainer. The twine brake is located in the outlet region of the binding arm and applies a certain resistance during the running of the twine, that results in a certain tension in the twine and thereby a certain retaining force. The retaining force is the result of the fact that the last strands of the twine are retained between underlying strands or in the baled crop as a result of friction. Furthermore the twine brake prevents the twine from retracting into the binding arm after the separating process. The separating arrangement is located between the cylindrical bale and the twine retainer. The twine retainer is located at the frame of the large round baler to the interior and spaced from its side wall, particularly between the binding arm and the separating arrangement. The piece of twine associated with the binding arm is held by the twine retainer after the separating process so that the twine can be drawn out of the binding arm at the beginning of the binding process on the basis of the movement of the binding arm.  
           [0003]    The problem underlying the invention is seen in the fact that the known twine brake can generate only a limited tension since otherwise the twine is drawn out of the twine retainer upon the movement of the binding arm or is not carried along after being grasped by the crop.  
         SUMMARY OF THE INVENTION  
         [0004]    According to the present invention, there is provided an improved twine feeding arrangement for a large round baler, which features a twine brake.  
           [0005]    An object of the invention is to provide a twine feeding arrangement wherein a twine brake is positioned between the twine separating or cut-off mechanism and the baling chamber.  
           [0006]    In this way the end region of the twine that had been cut off from the cylindrical bale is drawn out of the twine brake by it, while the region associated with the twine roll hangs out of the binding arm without tension and is ready for the next binding process. Since the tension remains in the part already cut off but not in the portion that remains in the binding arm, the portion remaining in the binding arm does not retract but hangs out of the binding arm without being shortened. The tension in the twine can be increased by a factor of four and even more compared to twine brakes known previously.  
           [0007]    A more specific object is to provide a twine brake in the form of a spring that has helical coils or several springs, for example, Belleville springs pressed upon each other or leaf springs. This makes possible an operation wherein, when the twine is drawn through the twine brake, it retains the twine tension and, depending on the position of the twine, the tension is increased if the twine is additionally drawn into the spring coils or between the spring elements.  
           [0008]    A simple and cost effective configuration is offered by a helical extension spring between whose coils or windings the twine can be drawn as long as rounded edges do not damage the twine. The introduction of the twine between individual spring coils or spring elements is always performed reliably if a catcher end, for example, a projecting section of windings at the beginning, a finger or the like is provided. While it would be possible to configure the spring as a one-piece component with an adjoining part or to weld this or these into place or otherwise to fasten permanently; in particular for a retrofit, however, it is advantageous if the spring(s) are provided with a retaining end through which, for example, a screw can be inserted so that even the spring tension is not reduced.  
           [0009]    Since on occasion the spacing between the end face of the cylindrical bale and the last layer of the twine must be made to conform to the type of crop to be baled or the further processing of the cylindrical bale, the spacial arrangement of the twine brake and a spacing retainer used can be maintained by connecting these to each other, that is, arranging them upon each other.  
           [0010]    Since the crop to be baled varies in stiffness, a sufficient insertion of the twine into the surface of the bale can in each case be assured by having the retaining or braking force of the twine brake adjustable.  
           [0011]    A twine brake according to the invention can be configured at a particularly favorable cost if a tine of a pick-up or a reel is used for this purpose or if it is formed thereby. Tines of this type are offered in large quantities as semi-finished parts.  
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a schematic, left front perspective view of the baling chamber and binding arrangement of a large round baler.  
         [0013]    [0013]FIG. 2 shows an enlarged view of the twine brake constructed in its preferred form as a coil tension spring.  
         [0014]    [0014]FIG. 3 shows an alternate embodiment of a twine brake constructed of a stack of Belleville springs. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    Referring now to FIG. 1, there is shown a portion of a large round baler  10  in which a housing  12  and a binding arrangement  14  can be recognized. The large round baler  10  may be of any known type, that is, with a fixed or a variable baling chamber, with a pre-chamber or the like. Such large round balers are offered, for example, by JOHN DEERE and therefore do not require any detailed explanation. It should merely be noted that the large round baler  10  is supported on wheels, moved along the ground and during operation takes up crop from the ground in order to shape it into a cylindrical bale  16 .  
         [0016]    Among other items, the housing  12  includes side walls  18  between which a baling chamber  20  is formed for the forming of a cylindrical bale  16 . Further details such as the baling means, outlet gate, etc. do not require an explanation here.  
         [0017]    The binding arrangement  14  contains a binding arm  22 , a separating arrangement  24 , a spacing retainer  26  and a twine brake  28 .  
         [0018]    The binding arrangement  14  is used to wrap twine  30  in a helical pattern on the circumference of the rotating cylindrical bale  16  at the end of the process of forming the bale, and to wrap several strands of twine upon themselves near its end face that are drawn into the crop and wedge themselves into the previously laid strands, whereby they are retained on the circumferential surface. The higher the tension force here exerted on the twine  30 , the stronger the strands are retained on the cylindrical bale  16 . Finally the twine  30  is separated from the twine supply, by operation of the separating arrangement  24 , and the finished and wrapped cylindrical bale  16  is rolled out of the large round baler  10 . In place of a single binding arrangement  14 , as shown, two binding arrangements  14  could be provided, in particular, in the region of each side wall  18 .  
         [0019]    The binding arm  22  can be pivoted about a vertical axis, not shown, in a generally horizontal plane, in such a way that in a region of the side walls  18  it assumes the greatest spacing from the cylindrical bale  16 , while in the central region of the cylindrical bale  16  it comes closest to the bale. In this embodiment the binding arm  22  is equipped with two outlets  32  from which the twine  30  can reach the cylindrical bale  16 ; in a corresponding manner, two strands of twine  30  are also provided each of which is wrapped about the circumferential surface of the cylindrical bale  16 . More or fewer strands of twine  30  and/or outlets  32  may also be provided. The twine  30  reaches the binding arm  22  from a supply roll, not shown, but known in itself, but is previously braked slightly, so that the twine  30  is not caught in the hollow binding arm  22 . At the end of the binding process the outlets  32  are located relatively close to the particular side wall  18  and could therefore guide the twine  30  to the outer edge of the cylindrical bale  16 . The binding arm  22  can also be pivoted in a vertical plane or a generally vertical plane.  
         [0020]    The separating arrangement  24  is also configured in conventional manner and contains an anvil  34 , a knife  36  and an actuating arrangement  38 . The anvil  34  is configured as a rigid steel plate that is fastened to the side wall  18  and is located at the end of the binding process in the region of movement of the twine  30 . The knife  36  is attached to the side wall  18  in a manner not shown but known in itself so as to pivot vertically and, except in its cutting condition, maintain a spacing to the anvil  34 , through which the twine  30  can extend. The knife  36  is generally configured as wide as the anvil  34 .  
         [0021]    The actuating arrangement  38  for the separating arrangement contains a spring loaded tension rod  40  with a stop  42  and a lever arm  44 . The actuating arrangement  38  is used to press the knife  36  against the anvil  34  and thereby to separate the twine  30 , as soon as the binding arm  22  approaches its end position. Accordingly the stop  42  is located in the region of movement of the free end of the binding arm  22  and is loaded by the latter, when this reaches the end of its movement. Thereupon, the stop  42  configured as a hook pulls on the tension rod  40 , which is connected with the lever arm  44  so as to pivot. The lever arm  44  is connected rigidly with the knife  36  and presses this against the anvil  34  when the tension rod  40  was moved in the corresponding direction. While the knife  36  presses the twine  30  against the anvil  34 , an increased tension develops for a brief period in the twine  30 , that has the effect that the twine  30  is drawn into the surface of the cylindrical bale  16  and becomes wedged into the remaining strands of the twine  30 .  
         [0022]    In this embodiment the spacing retainer  26  is configured as a steel rod bent in two places in opposite directions and is provided with a guide section  46  between the bends. The spacing retainer  26  is used to adjust the spacing of the last strands of the twine  30  from the end of the cylindrical bale  16  in order to avoid that the twine  30  slides off the edge of the cylindrical bale  16  and becomes loose. While the spacing retainer  26  may be attached rigidly, it may also be fastened so that is can be adjusted relative to the side wall  18 , as this was disclosed, for example, in EP-0 981 947.  
         [0023]    The description so far refers to the configuration of a large round baler  10  and a binding arrangement  14  as are known in the state of the art.  
         [0024]    The twine brake  28  is shown with the affected area of the spacing retainer  26  in the enlarged view of FIG. 2. According to this, the twine brake  28  is configured as the tine of a pick-up or of a reel in spring steel and contains spring elements  48 , a catcher end  50  and a retainer end  52 . Other configurations, particularly those of other materials such as plastic, composite materials and the like are equally possible. The attachment of the twine brake  28  on a spacing retainer  26  is not required, but only advantageous; rather the twine brake  28  can also be attached to the side wall  18  or the housing  12  itself at an appropriate location.  
         [0025]    The spring elements  48  are configured as four joined helical-shaped coils or windings that leave an interior space that is penetrated by the guide section  46  of the spacing retainer  26  in the axial direction.  
         [0026]    The catcher end  50  represents the beginning of the spring elements  48  on the one hand and extends initially in the axial direction and then bent from the tangent away from the spring elements  48  so that its end projects a considerable distance radially beyond the spring elements  48 .  
         [0027]    The retainer end  52  represents the opposite end region of the spring elements  48  and is configured in this embodiment as an eye as is known from tines on pick-ups and reels. The retainer end  52  is secured by means of a peg  54  on the spacing retainer  26 , whose guide section  46  is fastened, for example, welded. The peg  54  is configured as the shaft of a screw onto which a nut  56  can be applied in order to press the retainer end  52  against the guide section  46 .  
         [0028]    The orientation of the twine brake  28  and, in particular, the catcher end  50  is selected in such a way that, during the movement of the binding arm  22  to the end face of the cylindrical bale  16  or to the side wall  18 , the twine  30  is guided into the nip or gore area between the catcher end  50  and the spring elements  48  located towards the former. The closer the outlets  32  approach the side wall  18 , the deeper the twine  30  reaches between the spring elements  48  whereby the friction between the twine  30  and the spring elements  48  increases and therewith the tension in the twine  30 . This increased tension leads to the twine  30  being drawn particularly deep into the surface of the cylindrical bale  16  and between the strands of twine previously deposited and is retained there particularly well. As soon as the binding arm  22  reaches its end position and actuates the knife  36 , the twine  30  is separated. After the separation process, the high tension in the twine end that has been cut is maintained until this end has been drawn out of the twine brake  28  as a result of the further movement of the cylindrical bale  16 . The particular effect of the invention consists in the fact that the tension in the twine  30  exists between the knife  36  and the cylindrical bale  16  and not in the region between the binding arm  22  and the knife  36 .  
         [0029]    Referring now to FIG. 3, there is shown an alternate embodiment of the twine brake. Specifically, there is shown a twine brake  28 ′ in the form of four Belleville springs  60  stacked in series and held together by a bolt and nut assembly  62 . The adjacent springs  60  at the middle of the stack define a nip  64  for receiving a length of the twine  30  during the wrapping process. The tension afforded by the brake  28 ′ can be adjusted by loosening or tightening the nut of the bolt and nut assembly  62 . It is also to be noted that in lieu of the bolt, a rod member could be used which is formed to perform the respective functions performed by the spacing retainer  26  and guide finger  50  of the embodiment illustrated in FIG. 2, while still performing as the adjustable bolt and nut assembly  62 .  
         [0030]    Having described the preferred and one alternate 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.