Abstract:
A wrapping means tensioning device is provided for a round baler and comprises an idler assembly and an application assembly. Wrapping means, like net, when drawn during a wrapping cycle acts onto the idler assembly, which in turn will press an application element of the application assembly against a roll, on which wrapping means is stored. This provides for proper tension during a wrapping cycle without the need for springs or the like, the force of which would need to be overcome, when a wrapping device is brought into a non-operative loading mode.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a surface wrapping means tensioning device comprising a moveable application element acting directly or indirectly on a wrapping means roll and an idler element between the wrapping means roll and an object to be wrapped, deflecting said wrapping means, as well as to a round baler. 
       BACKGROUND OF THE INVENTION 
       [0002]    EP B1 1 099 366 discloses a device to load a net roll into a net wrapping system, wherein in an operative position, in which net can be drawn from a roll, a brake roll acts onto the surface of the net roll. The braking force is built up by a gas accumulator, which is tensioned by means of crank arms and links by an operator into a closed position. 
         [0003]    The problem this invention is based on is seen in the need to have crank arms and links or other big lever arm(s) to tension the gas spring or any other spring. This is an even greater problem, where the components are difficult to access, such as when the net wrap system is situated in the front of a round baler above the tongue. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the description herein no gas or other spring is needed to apply force on the wrapping means, as the tension is created by the wrapping means itself, like net, plastic, paper or any other means. The application element can be a simple rigid bar or one or more rolls on such a bar. Said application element may act onto the outer surface of a roll of wrapping means or it may act on an axle on which said roll is carried or onto a disc being rotatably connected to said axle. The application element could also be a flat or bent sheet metal, a grid or the like. The idler element is an element, over which the wrapping means is guided and which deflects the wrapping means out of a straight line or plane. The idler element can again be a rigid bar or revolving parts on an axle. Said rolling parts may rotate freely or against a brake force. It becomes apparent, that the force acting on the wrapping means and thus decelerating its movement will be the higher, the higher the deflecting movement and the stronger the force resulting from the deflecting will be. This means, that by properly selecting the length of lever arms etc. the braking force can be adjusted. This braking force will apply only, when the wrapping means is drawn over the idler element, which means that no force will act, when a new roll of wrapping means is loaded. 
         [0005]    By disconnecting the application element from the idler element it is possible to pivot the application element out of the way, such that a new roll with wrapping means can be inserted, whereas the idler element may rest in its position. Furthermore the application element can also be removed or swung away if access is needed to the wrapping means, like if an obstruction occurs. Disconnect may happen by an ordinary removal of a pin, a hook, a latch or other means, for which preferably no tool is required. 
         [0006]    Since the diameter of a wrapping means roll will decrease during operation, and since the application element will follow the outer diameter of the wrapping means roll, the geometrical relationship between the application element and the idler element will change. In order to assure, that the application element is applied against the wrapping means by the idler element in all positions a one way clutch or similar means, like a wheel-ratchet coupling are provided, which will adjust infinitely or in steps to the new relationship between these elements. The application element will always rest and act on the wrapping means, if it is hindered from moving away. One way of doing this is a one way clutch of any type, which ultimately may be even a spring, which assures, that the application element can move only towards, rather than away from the wrapping means roll. 
         [0007]    In order to keep the idler element in close contact with the wrapping means even if no pulling force is acting on it, i.e. in a non-wrapping stage, a force, like from a mechanical or gas spring acts on it, which however must be smaller than the force built up by the pulled and deflected wrapping means. Again, by choosing the proper dimensions this force can be adjusted to the size of and the forces acting in the machine, in which the wrapping means shall be used. 
         [0008]    The application element will always stay in close contact with the wrapping means and will immediately exert its braking force, if a spring presses it against the wrapping means or if it is elastic in itself and is put under pretension by the idler element during wrapping. If it is elastic in itself, this may happen by choosing an elastic material like plastic, thin sheet metal or bars, or by an assembly of parts between which springs (coil, spiral, flat) may act. 
         [0009]    Undue movement of the idler element or of the application element will be avoided and proper alignment between them will be maintained, if the path of the idler element is restricted like with a slot, stops, a cable or chain, etc. This will help to assure, that the tensioning device does not bring itself into a state of self-squeezing. 
         [0010]    A roll on which the wrapping means roll rests and over which the wrapping means is trained over a considerable part of its circumference, will—especially if provided with a high friction surface—assure, that the wrapping means does not slip and sufficient tension can be built up in it, which also has the ability to deflect the idler element. When the wrapping means is routed to the idler element on the side of the roll opposite of the wrapping means, the angle of surrounding the roll with wrapping means can be adjusted and the whole device can be created with little space required. 
         [0011]    While a special case could be provided to receive the wrapping means roll and to keep it in place it is preferred to use existing parts like the roll and/or the application element to locate it. Depending on the friction needed on the circumference of the wrapping means roll to build up a certain pulling force in the wrapping means one may chose between a fixed surface on a stationary part having a high friction surface as one extreme and a freely rotating roll as another extreme to act on the roll. 
         [0012]    The application element may perform an additional function, if it is used as a loading platform and if said wrapping means roll can be brought from or by means of an application assembly into a position in which wrapping means may be withdrawn. For that purpose the application assembly may be formed as a covered surface, as an assembly consisting of transverse and longitudinal bars, straps, etc., which e.g. may be pivoted as an assembly about a bearing, and where appropriate a lever or motor may be provided to assist in this pivot movement if the wrapping means roll is too heavy. 
         [0013]    While this invention may be used in any type of a round or roll baler, it is applied preferably on a mobile round baler as it is used in agriculture, forestry or industry, like for tobacco, garbage, cotton etc. i.e. at places where loading and installation of wrapping means happens manually and where operators can hardly reach the wrapping device like at the front of a round baler and above a tongue. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    Two embodiments of the invention will be described in more detail below with reference to the drawings wherein: 
           [0015]      FIG. 1  is a schematic side view of a round baler, being provided with a wrapping means tensioning device; 
           [0016]      FIG. 2  is a side view of the wrapping means tensioning device according to a first embodiment in an operational state shown in solid lines; 
           [0017]      FIG. 3  is the wrapping means tensioning device according to  FIG. 2  in a non-operational state, in which no tension appears in the wrapping means; 
           [0018]      FIG. 4  is the wrapping means tensioning device according to  FIG. 2  in a loading state; 
           [0019]      FIG. 5  is a side view of the wrapping means tensioning device according to a second embodiment in an operational state, 
           [0020]      FIG. 6  is a front view the wrapping means tensioning device according to  FIG. 5 ; 
           [0021]      FIG. 7  is a coupling used in the wrapping means tensioning device to connect or disconnect an application element to/from an idler element; and, 
           [0022]      FIG. 8  is the wrapping means tensioning device according to  FIG. 5  in side view, but with an application arm formed flexible in itself. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0023]      FIG. 1  illustrates a round baler  10  having a frame  12 , wheels  14 , a tongue  16 , pressing elements  18 , a wrapping device  20  and a wrapping means tensioning device  22 . 
         [0024]    The round baler  10  illustrated is of the type used in agriculture and is thus widely known. It is of the fixed chamber type, which is just a choice; it could be of the variable chamber or of the hybrid type. 
         [0025]    The frame  12  is an assembly of parts bolted or welded together as is well known, to create a bale chamber  24  and to carry a crop pick-up  26  and other components not shown. 
         [0026]    The wheels  14  and an axle (not shown) support the frame  12  on the ground to be pulled over a field. 
         [0027]    The tongue  16  connects to the frame  12  at the front side thereof and is used to connect the round baler  10  to a tractor (not shown). As can be seen in  FIG. 1  and depending on the overall size of the round baler  10 , the wrapping device  20  may easily be at a height of app. 1.6-1.8 meters. 
         [0028]    The pressing elements  18  in this case are shown as rigid, rotatable rolls being located substantially in a circle, whereas in the lower front area an entrance is provided to enter crop and whereas the pressing elements  18  are located in a moveable and in a stationary housing which can be moved apart from each other to eject a bale. Instead of the rolls, belts, chains, etc. could be used as pressing elements  18 . The pressing elements  18  leave a gap  28  to feed wrapping means into the bale chamber  24 . 
         [0029]    The wrapping device  20  is determined to feed wrapping means  32  into the bale chamber  24  to wrap a bale (not shown) therein. Besides a cutting and a feeding device, which both are not shown for the sake of brevity, but are of ordinary and well known design, the wrapping device  20  comprises a wrapping means tensioning device  22 , which will be explained in more detail below. 
         [0030]    The wrapping means tensioning device  22  to carries a roll  34  with wrapping means rolled on it and delivers it to the bale chamber  24  thereby applying a certain tension in the wrapping means  32 . Hereto the wrapping means tensioning device  22  comprises a roll  36 , an idler assembly  38  and an application assembly  40 . 
         [0031]    The roll  36  is oriented such, that its longitudinal axis runs parallel to that of the roll  34  and of the pressing elements  18 . Roll  36  is journaled in the frame  12  by known bearings and is covered with rubber to apply high friction forces on the wrapping means  32 . The roll  36  is located with a distance to a part of the frame  12 , like a wall, whereas said distance is smaller than the diameter of the core of the roll  34  after all wrapping means  32  is used up. Finally, roll  36  supports roll  34  in the operation mode. 
         [0032]    The idler assembly  38  comprises an idler element  42 , an idler linkage  44 , a spring  46  and a ratchet  48 . The idler assembly  38  serves to use energy from the pulling force of the wrapping means  32  and to translate it into a braking force for the wrapping means  32 . The idler assembly  38  is located underneath the roll  36  with a pivoting axis, again being parallel to the axis of rotation of the roll  36 . 
         [0033]    The idler element  42  is formed as a roll journaled on a cross-bar (not shown), but received by the ends of the idler linkage  44  at both sides. The idler element  42  is preferably as long as the rolls  34  and  36 , but may be shorter or longer as well. The idler element  42  is moveable along its radial line for a short distance determined by slots  50  formed in another part of the frame  12 . The orientation and location of the slots  50  and the travel range of the idler element  42  are chosen such that the idler element  42  is always laterally of a straight line extending between the gap  28  and the line on the roll  36 , from which the wrapping means  32  departs. 
         [0034]    The idler linkage  44  has two arms  52 , each with a long and a short leg assuming substantially an inversed L-shape, in which both legs are rigidly connected to each other. At the free end area of the long legs the cross bar or a bearing for the idler element  42  is received. The free end area of the short leg is journaled on a shaft  54  fixed to the frame  12  and having a longitudinal axis parallel to that of the idler element  42 . The long and the short leg include an angle of about 100 degrees. As a result of this design the idler element  42  pivots in a vertical direction about the shaft  54  within limits defined by the slots  50 . 
         [0035]    Spring  46  is formed as a coil tension spring, but could be of any other type as well, and is, in this case, fixed with its one end to the frame  12  and with its other end to the ratchet  48 . The location and orientation of the spring  46  is such, that it activates the ratchet  48  and at the same time pivots the idler linkage  44  towards the roll  36 , whereas it is moved against the force of the spring  46  by the deflected wrappings means  32  as will be explained later. 
         [0036]    The ratchet  48  is pivotally connected to the idler linkage  44 , in this case, where the short and the long leg meet. The ratchet  48  has a driver leg  56  and a handle  58 , which are rigidly connected to each other. The driver leg  56  is determined to engage in a tooth profile  60  on the application assembly  40 , whereas the handle  58  will be used to bring said driver leg  56  out of engagement with said tooth profile  60 . Engagement of the driver leg  56  with the toothed profile  60  will be provided by means of the spring  46 . Ratchet  48  and toothed profile  60  form a one-way clutch  74 . 
         [0037]    The application assembly  40  comprises an application element  62 , application arms  64  and a spring  66 . It is the purpose of the application assembly  40  to transfer the movement received from the idler assembly  42  into braking movement acting onto the roll  34  with wrapping means  32 . 
         [0038]    The application element  62  is either formed as a bar rigidly kept at its ends by the application arms  64 ; or it is formed as another roll, rotatably received on a crossbar fixed with its ends to the application arms  64 . The application element  62  contacts the outer surface of the roll  34  either on its entire length or on parts of it only. In the case of a rigid bar it may also be provided with a rubber layer. 
         [0039]    The application arms  64  are provided at least on each side of the round baler  10  and receive in one end area the application element  62  and are provided with the toothed profile  60  at the other end. The application arms  64  may pivot on shaft  54  between a loading position—dashed lines in  FIG. 2 , solid lines in FIG.  4 —and an operation position, shown in solid lines in  FIG. 2 . While an upper part of the application arms  64  is formed like a sheet metal or strap, its lower part is substantially of triangular shape in the center of which it is journaled on shaft  54 . 
         [0040]    The spring  66  is formed as a gas spring, a coil pressure spring or any other kind, which is suitable to pivot the application arms  64  towards the roll  34 , i.e. in  FIG. 2  in a clockwise direction. The spring  66  is attached with one end to the frame  12  and with the other end to the respective application arm  64 , assuming one is provided for each. In the embodiment shown, the connecting point of the spring  66  at the application arm  64  moves from one side of the shaft  54  to the other and thereby passes a dead center position thereby. As a result the spring  66  assists a movement of the application assembly  40  into the loading position as well as into the operation position, in which the application element  42  applies against the roll  34 . 
         [0041]    The toothed profile  60  forms the lower edge of the substantially triangular part of the application arm  64 . The teeth of the toothed profile are of the saw type and are dimensioned and oriented such, that the driver leg  56  can engage with them in one direction, but slides over them in the opposite direction. 
         [0042]    Starting from this description the first embodiment will operate as follows, starting from a situation as it is shown in  FIG. 4 . The application assembly  40  assumes a loading position, in which the application arms  64  form sort of a trough in which the roll  34  with rolled-up wrapping means  32  may be stored. The ratchet  48  is out of engagement with the toothed profile  60  and the idler element  42  assumes its uppermost position at the end of the slots  50 , to which it is urged by the springs  46 . The springs  66  are extended. In order to bring the wrapping means tensioning device  22  into its operation mode, the application assembly  40  is pivoted about shaft  54  in clockwise direction when looking onto  FIG. 4 . At the end of this pivoting movement—see FIG.  3 —the roll  34  will assume a position between the frame  12 , the roll  36  and the application element  62 . The wrapping means  32  will be routed over the roll  36  at the side opposite the idler element  42 , then over the idler element  42  and finally into the gap  28 . As soon as the drive leg  56  gets into contact with the toothed profile  60  it will be forced between two teeth by the spring  46 . The spring  66  now acts on the other side of the shaft  54  and urges the application element  62  against the surface of the roll  34 . Idler element  42  is still in its upper position due to the action of springs  66 . As it can be seen in  FIG. 3  the wrapping means  32  is still loosely hanging over idler element  42 . Reference is now made to  FIG. 2 , solid lines. As soon as the wrapping means  32  is fed through gap  28  into the bale chamber  24  by any means, like a so-called duck-bill, by feeding rollers, by a blower or the like, and after the wrapping means  32  is pulled by a bale rotating in the bale chamber  24  tension will build up in the wrapping means  32 . This tension tends to move idler element  42  into a position, in which the wrapping means  32  can follow a straight line, although this is not possible ultimately, since the slots  52  limit the said movement. As soon as the idler element  42  and the idler arms  44  pivot about shaft  54 , ratchet  48  will push the toothed profile  60  in clockwise direction about shaft  54 . This clockwise rotation will cause the application arm  64  to press against roll  34 . With decreasing diameter of roll  34  the application arms  64  will follow its surface assisted by the virtue of the spring  66 , which will also avoid, that the application element  62  gets off the roll  34 . With decreasing diameter of the roll  34  also the toothed profile  60  will pass the driver leg  56  and after a certain movement the driver leg  56  will enter the next teeth gap, which assures, that a movement of the idler element  42  will always cause a movement of the application element  62 . Once the roll  34  is used up, ratchet  48  will be disconnected from the toothed profile  60  by pushing on handle  58 . This will allow an operator to pivot the application assembly  40  in counterclockwise direction into the position shown in  FIG. 2  in dashed lines. 
         [0043]    Reference is now made to  FIGS. 5 to 8  showing the second embodiment. As to be seen especially in  FIG. 5  except the ratchet  48  and toothed profile  60  assembly and the spring  66  first and the second embodiment are identical. 
         [0044]    As can be seen in  FIG. 7  shaft  54  is freely rotatable received in a hub  68  having a radially extending arm  70  and carries rotatably fix an arm  72 , which can be brought into alignment with and close to each other. Idler arm  44  is journaled on said hub  68  by means of one-way clutch  74 , which now has the ratchet  48  and toothed profile  60  in the space between the bushing like end area of idler arm  44  and the hub  68 . Instead of the toothed profile  60  another friction surface may be used, which provides for drive in one direction and no drive in the opposite direction. This one-way clutch  74  may be an off-the-shelf item installed in said space. This one-way clutch  74  will act in the same way and in the same direction as the one of the first embodiment. 
         [0045]    Application arms  64  are rotatably fixed on shaft  54  at both of its ends to rotate with it as described with respect to the first embodiment. 
         [0046]    Beside one-way clutch  74  and also on the hub  68  is provided another one-way clutch  76 , now between the hub  68  and a retainer  78  fixed to the frame  12 . One-way clutch  76  acts similarly to spring  66  in as much as it keeps the application element  62  in contact with roll  34 . This is because shaft  54  is rigidly connected to the application arms  64  as well as to the hub  68  via arm  72  and can rotate in the retainer  78 , i.e. with respect to the frame  12  only in one direction. Instead of this other one-way clutch  76  other means, like spring  66 , may be provided to assure, that application element  62  rests on roll  34 . 
         [0047]    Arm  70  has one or more bores  80  or notches in its remote end area. 
         [0048]    Arm  72  is of the fork type with a series of aligned bores  82 , which can be brought into a position in which they are aligned with bore  80  in arm  70 . Bores  82  slidably receive a pin  84 , which is urged in known manner by a spring towards bore  80 , but can be drawn apart from it, such that both arms  70 ,  72  can pass each other. 
         [0049]    According to  FIG. 6  one hub  68  in the middle of the whole assembly may be sufficient; however if appropriate one hub  68  may be provided in both end areas of shaft  54 . 
         [0050]    Subsequent to the foregoing description the function of the second embodiment is as follows. Once roll  34  is in its operation position and wrapping means  32  is drawn by the bale and deflecting idler element  42 , idler arm  44  will via one-way clutch  74  rotate hub  68  and via arms  70 ,  72  and pin  84 —now protruding through all bores  80 ,  82 —also shaft  54  and thereby application arms  64  as in the first embodiment. In order to bring application arms  64  into a loading position similar to that shown in  FIG. 4 , pin  84  is pulled out of bore  80  and thus application arms  64  are free to rotate with shaft  54  to the loading position, since the one-way clutches  74 ,  76  are rendered ineffective as they act on the hub  68 , rather than on shaft  54 . After a new roll  34  is loaded into the wrapping device  32  pin  84  is reinserted into bore  80 . In case bores  80 ,  82  would not match, either another bore or notch  80  may be selected or hub  68  may be rotated until all bores  80 ,  82  match. 
         [0051]    As to be seen in  FIG. 8 , application arms  64  maybe elastic in themselves to apply always a minimum pressure onto roll  34 . 
         [0052]    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.