Abstract:
A round bale baling apparatus includes an accumulator for rolling crop material into a round bale, a twine dispenser adapted to hold and dispense twine, and a twine tensioner. The twine tensioner is adjustable and includes an energizable actuator and switch for operating the actuator to adjust the twine tension. Specifically, the switch can be manipulated to selectively decrease tension on the twine during initial gripping of the free end of the twine by a rolling loose bale, and to selectively increase tension on the twine once the twine is sufficiently wrapped onto the bale to provide a secure pulling force. The actuator can be electric, such as a reversible DC motor or solenoid, or can be another energizable device actuable from a remote position. Methods related to the above are also defined.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates to twine tensioners for crop balers adapted to make round bales, where the twine tensioner regulates tension in the baler twine as the twine is applied to the round bales during the bale wrapping process.  
           [0002]    A problem exists in the round hay baler industry. The problem is related to the fact that in order to start the bale wrapping process in most round balers, a relatively loose section of twine must be introduced into the hay feeder system at a location close to a rolling bale until the twine catches on or is grabbed by the bale and is drawn into the machine around the bale. Twine that is too tightly held or tensioned at the beginning of the operation will not catch on the bale, thus wasting time and creating frustration. Twine that is loose enough to be easily drawn into the machine and around a newly formed bale under most conditions is usually lacking in sufficient tension to adequately tightly wrap the bale. Loosely wrapped bales fail to retain their shape, do not handle well, and can fall apart, resulting in significant forage losses.  
           [0003]    An additional problem is that knives for cutting twine function better when the knives make contact with well-tensioned twine. Thus, a poor twine tension not only leads to a poorly wrapped bale, but also can lead to poor cutting of the twine. This leads to wasted time for gathering crops.  
           [0004]    Attempts have been made to remedy the above-described problems. However, such attempts have invariably led to systems that are extensive, expensive, cumbersome, complicated, and prone to breakdowns.  
           [0005]    Accordingly, a twine tensioner is desired solving the aforementioned problems and having the aforementioned advantages.  
         SUMMARY OF THE PRESENT INVENTION  
         [0006]    In one aspect of the present invention, an apparatus for balers includes an adjustable twine tensioner adapted to adjustably tension twine, an energizable actuator connected to the twine tensioner for adjusting the twine tensioner, and a control operably connected to the actuator for energizing and operating the actuator to selectively adjust the twine tensioner during a bale wrapping process of a baler, and thus selectively increase and decrease tension in twine associated with the twine tensioner.  
           [0007]    In a narrower aspect, the apparatus for making round bales includes a crop accumulator adapted to pick up and roll crop material into a round bale, a twine dispenser adapted to hold and dispense twine and to position a free end of the twine proximate the bale such that, as the bale is rolled, the free end of the twine catches on the bale and the twine is pulled around the bale. The twine tensioner is positioned to selectively tension the twine being dispensed from the twine dispenser to the crop accumulator.  
           [0008]    In another aspect of the present invention, a method of tensioning twine includes steps of providing an adjustable twine tensioner adapted to adjustably tension twine, and providing an actuator operably connected to the twine tensioner for adjusting the twine tensioner. The method includes selectively switching the twine tensioner between high and low twine tensioning positions by operating a switch operably connected to the actuator to thus selectively increase and decrease tension in twine for optimal tension during the bale wrapping process.  
           [0009]    In another aspect of the present invention, a method of tensioning twine around bales of crop material includes steps of extending a free end of twine close to a rotating bale of crop material until the free end is caught and pulled with a reliable pulling force by the rotating bale, with the twine, at most, loosely restrained by a twine tensioner, and after the free end is drawn around the bale sufficiently to establish a reliable pulling force, substantially increasing tension on the twine by the twine tensioner such that the twine is tensioned and drawn tight against the bale as the twine is wrapped repeatedly around the bale.  
           [0010]    An object of the present invention is to provide an energizable twine tensioner that can be remotely controlled for selective twine tensioning without a need to dismount a tractor.  
           [0011]    Another object of the present invention is to provide an electrically motivated means for adjusting twine tension in a round baler twine as that twine is introduced into the baler, with the twine tension being optimal and different at different segments of the bale wrapping operation.  
           [0012]    These and other features, objects, and advantages of the present invention will become apparent to a person of ordinary skill upon reading the following description and claims together with reference to the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0013]    [0013]FIG. 1 is a side view of a round hay baler, including a side partially broken away to show an internal twine tensioner;  
         [0014]    [0014]FIG. 2 is an enlarged fragmentary view of the twine tensioner of FIG. 1, the twine tensioner including a reversible DC motor drive;  
         [0015]    [0015]FIG. 3 is a rear view of the twine tensioner in FIG. 2 with the tensioner being in a twine-tensioning down position;  
         [0016]    [0016]FIG. 4 is a rear view similar to FIG. 3, but with the tensioner being in a twine-released up position;  
         [0017]    [0017]FIG. 4A is a rear view of a modified twine tensioner similar to the twine tensioner of FIG. 3 but having a spring-buffered release feature on its pressure foot;  
         [0018]    [0018]FIGS. 5 and 6 are electrical diagrams of the electrical circuit for operating twine tensioners of FIGS. 3 and 4A;  
         [0019]    [0019]FIGS. 7 and 8 are side and rear views of a modified twine tensioner similar to the twine tensioner of FIG. 3, but including a solenoid drive;  
         [0020]    [0020]FIG. 9 is an electrical diagram of the electrical circuit for operating the twine tensioner of FIG. 7;  
         [0021]    [0021]FIGS. 10 and 11 are side and rear views of another modified twine tensioner similar to the twine tensioner of FIG. 3, but including a reversible DC motor drive that incorporates a pivot to reduce a rate of travel of the pressure foot; and  
         [0022]    [0022]FIG. 12 is a schematic view showing an existing round baler retrofit with the present inventive apparatus. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]    A round bale baling apparatus (hereafter called baler  20 ) (FIG. 1) includes an accumulator chamber  21 ′ for receiving and rolling crop material into a round bale  18  (FIG. 12). The baler  20  (FIG. 1) includes a twine dispenser  21  adapted to dispense twine  22  around each newly formed round bale, and a twine tensioner  23  for variably controlling twine tension as the bale  18  is rolled and the twine  22  is wrapped around the bale  18 . The twine tensioner  23  (FIG. 2) includes an energizable actuator  24  for adjusting the twine tensioner  23  to provide the variable twine tension to facilitate starting the wrapping process and also to provide sufficient tension after the twine  22  begins to wrap around the bale. An actuator control circuit  25  (FIG. 5) includes a switch  26  for selectively and remotely controlling operation of the actuator  24 . By manipulating the switch  25 , the twine tensioner  23  can be adjusted to a low tension (or no-tension condition depending on the tensioner design) which allows a free end  27  (FIG. 12) of the twine  22  to be easily and quickly grabbed by the rotating bale  18 . By further manipulating the switch  25 , the twine tensioner  23  can be adjusted to a higher tension once the twine  22  is reliably grasped by the bale  18 , thus allowing the bale  18  to be wrapped with an optimal twine tension to create an optimally tight bale  18  that can be handled with minimal forage loss.  
         [0024]    The illustrated twine tensioner  23  (FIG. 2) is mounted to a vertical plate  30  that forms an upright support. Nonetheless, it is contemplated that the twine tensioner  23  could be mounted on existing structure on the baler, if desired, or that the arrangement could be made non-vertical, if desired. The illustrated twine tensioner  23  includes an L-shaped bottom stand  31  with a top support plate  32  over which the twine  22  passes. The twine tensioner  23  includes a pressure foot  33  (sometimes called a “floater plate” herein) for pressing the twine  22  against a top surface of the support plate  32  to create tension in the twine  22 . The actuator  24  includes a lift mechanism comprising a reversible DC motor  34 , a drive mechanism  35  connected to the motor  34 , a carrier bracket  36  attached to the foot  33  and operably connected to the drive mechanism  35 , and an adjustable spring tensioning arrangement  37 . The motor  34  is preferably a 12 volt 1/50 HP reversible DC motor so that it is easily connectable to the tractor electrical system, although it is contemplated that other electric or non-electric motors and actuators could be used. Specifically, it is contemplated that the present invention can include different actuators, such as hydraulic, pneumatic, or power-take-off driven actuators, such as are commonly found on modem tractors. The illustrated reversible DC motor  34  includes a rotatable shaft  38  (FIG. 3) and a coupler  39  for attachment to a threaded drive shaft  40 . The carrier bracket  36  includes a box-like housing shaped to maintain a relatively clean area around the threaded drive shaft  40 , and includes a top  42  and a bottom welded or otherwise secured to the foot  33 . Notably, the support plate  32  and/or the foot  33  preferably includes an angled portion  33 ′ (see FIGS. 2 and 3) forming an inlet chute to assist in feeding twine  22  into and under the foot  33 . A drive nut  43  (FIG. 3) (which may include a washer, if desired) is captured within the housing to prevent rotation as threaded drive shaft  40  is rotated. Thus, the drive nut  43  moves upwardly or downwardly as the drive shaft  40  is rotated by the motor  34 . A top bolt  44  extends transversely through the housing and is engaged by the drive nut  43  as the motor  34  rotates to lift the carrier bracket  36 . As the carrier bracket  36  is lifted, the foot  33  is also lifted. A bottom bolt  44 ′ can act as a bottom stop, but in the illustrated device, it is merely intended to prevent the nut  43  from coming off a bottom of the drive shaft  40 .  
         [0025]    A pair of guide bolts  45  extend vertically through the support plate  32  and through the foot  33 . The bolts  45  each include a top section that extends about equal in height to the top  42 , and a coil spring  46  is positioned on each bolt  45 . A top nut  47  is threaded onto each bolt  45  to capture each spring  46  on the top section of each bolt. The springs  46  press on the foot  33 , and by turning the top nut  47 , the tension of springs  46  can be increased or decreased on the foot  33 . When the foot  33  is lifted to its tension-relieved position (FIG. 4), the foot  33  is moved upwardly against a tension of the springs  46  and the springs  46  are compressed, thus releasing pressure on the twine  22  located between the support plate  32  and the twine  22 . When the motor  34  is reversed, the foot  33  is lowered against the support plate  32  (FIG. 3), with the tension of springs  46  applying a downward pressure on the foot  33 . By adjusting the top nut  47 , the tension on the twine  22  can be adjusted to different twine-tensioning positions. Nonetheless, the reader should understand that adjustment of top nut  47  changes the tension given to the twine when the twine tensioner  23  is in a down position. It is the operation of motor  34  that causes the twine tensioner  23  to lift the foot  33  and move it to the tension-relieved position where the tension is minimal or nonexistent regardless of the position of top nut  47 .  
         [0026]    In a modified twine tensioner  23 ′ (FIG. 4A) a washer  50  is added above the drive nut  43 , and a spring  51  is located between the washer  50  and the drive nut  43 . The spring  51  is held in compression between the square drive nut  43  and the retainer screw  44 . This compression of spring  51  exerts a vertically up force on the tensioner foot  33  in opposition to the vertically down force exerted by springs  46 . The vertically down forces applied by springs  46  on the foot  33  are thus opposed by the combination of the twine compression force and the compression force existing in spring  51 . At any given adjustment of springs  46 , the clamping force of the tension foot  33  thus becomes adjustable depending upon the position of drive nut  43 . The twine tension clamping force exerted on the twine by the foot  33  is readily adjustable simply by operation of the gear motor as controlled by the tractor mounted rocker switch  26 . Thus by the addition of spring  51  to the embodiment as shown in FIG. 4, a means is possible, if desired, for slowing the vertical clamping motion of the foot  33 . Precise adjustment of the resulting twine tension on the bale being wrapped is thereby more readily obtained by judicious use of the rocker switch  26 .  
         [0027]    Further adjustment of the action of the tensioner as illustrated in FIG. 4A is provided by carefully choosing the compression values of springs  46  and spring  51 . This can be done in response to variations in design between balers and to variations in field conditions. Different operators may have preferences also.  
         [0028]    The control circuit  25  (FIG. 5) includes a power-side conductor  55  with a fuse  56  therein and a groundside conductor  57  operably connecting the switch  26  to the electrical system  54  of the tractor pulling the baler  20 . Switch  26  further includes conductors  58  and  59  connected to the motor  34 . The switch  26  (FIG. 6) is a double throw, double pole switch, spring-biased to a neutral “off” position, with the input and output nodes  60  and  61  connected to the conductors  55  and  57 , respectively. The switching element (not shown) is movable to a first position FP where the node  60  is connected to the motor conductor  58 , and where the node  61  is connected to the motor conductor  59 , thus supplying 12v DC electrical power to the motor  34  for rotating the motor  34  in a first direction. The switching element is movable to a second position SP where the node  60  is connected to the motor conductor  59 , and where the node  61  is connected to the motor conductor  58 , thus supplying 12v dc electrical power to the motor  34  for rotating the motor  34  in an opposite second direction. This can be done with “cross wires”  62  and  63  as shown in FIG. 6.  
         [0029]    Operation of the twine tensioner  23  is described as follows. The gear motor output shaft is reversible in response to changes in polarity of the voltage (12v) applied. Polarity change for shaft rotational direction change is accomplished using the double pole-double throw rocker switch  26 . The illustrated switch  26  is mounted on the tractor and is conveniently labeled to indicate direction of tension change. Loosening or tightening can be indicated by a letter “L” or “T”. The center or normal position of the switch  26  is the neutral or zero output position. Depressing or moving the rocker switch  26  to the “L” position will result in movement of the gear motor output shaft  38  in the clockwise direction as viewed from the up side. This rotation will cause vertical “up” travel of the threaded nut  43  on the short length of the threaded drive rod  40  coupled to the output shaft. This nut  43  cannot rotate as it is confined by its location in the lifter post (i.e. housing bracket  36 ). The threaded nut  43  is thus caused to travel vertically “up”. Because it is in contact with the upper stop  44  upon the lifting post, this vertical motion of the threaded nut results in relief of the pressure (force) being exerted by the compression existing in the tension springs  46  upon the twine floater plate (i.e. foot  33 ) which in turn results in reduction of the clamping force existing between the floater plate and opposing base plate ( 32 ). This action thus gradually releases the twine to approximately zero drag as the motion continues. Twine tension is increased by reversing the action as outlined above by simply moving the rocker switch  26  in the opposite direction “T” position. Thus, any degree of desirable twine operating tension required for baling can be achieved without a need to leave the tractor seat. This is especially important since when starting the bale wrapping sequence, a relatively free twine is normally required to start the twine to wrap around a new round bale. But the twine must be more highly tensioned in order to maintain bale shape and integrity and to ensure clean severance of the twine by the knives at the end of the wrapping procedure.  
         [0030]    Modified twine tensioners  23 A and  23 B (FIGS.  7 - 9  and FIGS.  10 - 11 , respectively) are similar to the twine tensioner  23 , and the same identifying numbers are used for identical or similar features and components, but with the addition of the letter “A” and “B”, respectively. This is done to reduce redundant discussion and not for another purpose.  
         [0031]    The modified twine tensioner  23 A (FIG. 7) includes a solenoid  34 A that replaces the DC motor  34 . A shaft  38 A extends from the solenoid  34 A, and a nut  43 A retains the shaft  38 A to the carrier bracket  36 A. A spring  65 A is positioned around the shaft  28 A and biases the solenoid shaft  38 A to a normally extended position. In the extended position, the springs  46 A bias the foot  33 A to a twine-engaged tensioning position. When the solenoid  34 A is electrically actuated, the shaft  38 A is drawn into the solenoid  34 A, causing the foot  33 A to move against the bias of springs  46 A and to move to a twine-loosened position. A push-button switch  26 A (FIG. 9) replaces switch  26 , and only a single conductor  55 A (with fuse  56 A) extends from the tractor electrical system  54 A to push-button switch  26 A, and a single conductor  58 A extends to the solenoid  34 A. A single conductor  59 A extends to the ground on the baler  20 A, which is electrically connected to the tractor electrical system  54 A through the baler&#39;s hitch. By touching the push button switch  34 A for a short time, the farm worker can actuate the solenoid  34 A to raise the foot  33 A and loosen tension on the twine  22  so that the twine  22  will be quickly and reliably grabbed by the rotating bale of crop material. Once the twine is securely grabbed, the push button switch  34 A is released, and springs  46 A bias the foot  33 A against the twine  22  to tension the twine  22  for optimal bale wrapping.  
         [0032]    Operation of the twine tensioner  23 A is described as follows. This solenoid  34 A operated twine tensioner provides two (2) levels of twine tension. When the solenoid  34 A is energized by operation of switch  26 A, it lifts the twine floater plate (i.e. foot  33 A) and frees the twine  22  for trouble-free starts of the bale wrapping process. After the twine  22  is started, the solenoid  34 A is de-energized and a higher level of tension desirable for wrapping is provided. The invention in this embodiment is electrically energized and utilizes an automotive-type solenoid (typically 12v). In this embodiment, the twine tensioner floater plate (i.e. foot  33 A) is manually adjusted using the two adjusting nuts  47 A to compress the tensioning springs  46 A. The springs  46 A are adjusted to provide optimal tension as required for the characteristics of the baler used and the type of hay being baled. The twine wrapping process begins when the twine placement tubes (arms or other mechanism) reach the desired location on the hay bale face. The twine  22  will start feeding into the baler when friction with the hay being drawn into the baler is sufficient to grasp the twine  22  and drag it into the hay feeder section. At this point in the process, the baler operator will momentarily (1 to 2 seconds) depress a push button switch  26 A (normally off type) which will energize the solenoid  34 A to lift the twine floater plate (foot  33 A) and release the twine  22  for easy entry into the baler. This starts the wrapping process. The baler operator will then release the push button  26 A to de-energize the solenoid  34 A and the twine tensioner springs  46 A return the floater plate (foot  33 A) to its previously established set position for desirable twine tension. On many machines, operation of the solenoid at the start of the wrapping process can be electrically timed or synchronized with the twine placement mechanism to make the operation fully automatic, eliminating the operator&#39;s need to depress a push button.  
         [0033]    The modified twine tensioner  23 B (FIG. 10) is very similar to the twine tensioner  23 , but the twine tensioner  23 B includes a lever or pivot arm  70 B that operates between the motor  34 B and the foot  33 B. The lever  70 B is pivotally mounted on a stand  71 B at pivot  72 B. One arm  73 B of the lever  70 B includes a drive nut  43 B that engages the threaded drive shaft  40 B on the motor  34 B. The second arm  74 B includes a downwardly extending section  75 B that engages and is secured to the foot  33 B. The illustrated arm  73 B is about twice an effective length of the arm  74 B, such that the foot  33 B moves about half the distance of the drive nut  43 B, and with about half the velocity. The illustrated motor  34 B has a 362:1 gear reduction, resulting in about 16 rpm. The joint between arm  74 B and section  75 B includes a slot  76 B and loose pin  77 B, providing flexibility to the joint, such as if a knot in the twine passes under foot  33 B.  
         [0034]    Operation of the twine tensioner  23 B is described as follows. Switch  26  is closed to energize the gear motor  34  provides an output shaft torque of 120 oz. inches at 16 rpm. The rocker switch is used to reverse polarity of the DC gear motor circuit and allows reversal of the shaft rotational output. A ¼″ diameter×1-¾ long threaded rod coupled to the gear-motor shaft rotates to cause a ¼″ square machine nut, which is loosely fitted on the threaded rod to travel up or down on the rod since it is constrained from turning by confinement in the fork of the lifting lever. Rotation of the rod in the clockwise direction (when viewed from above) will result in a vertically-upward motion of the ¼″ nut  43 B (FIG. 11). This upward motion of the nut is transferred to the floater plate as a downward motion and increases the compression on the twine due to the rotation of lever  70 B. The hole at the top of the floater plate lifting post is (i.e. lift bracket  75 B) elongated to provide slack in the fit of the lever-operating rod. It will normally be in contact at the top of this opening with some slack (about {fraction (3/16)}″) under the extended operating lever rod. This insures freedom of movement and allows the floater plate (i.e. foot  33 B) to respond to variations in twine thickness without significant variation in applied force. The motivating force is that established by previous adjustment of the tensioner adjusting springs  46 B. Vertically up motion of the lifter reduces the total spring pressure and vertically down motion increases this pressure. Rotation of the gear motor shaft and coupled threaded rod in a counterclockwise direction (as viewed from above) will result in a vertically downward motion of the ¼″ nut. The ¼″ nut moving downward forces the forked end of the lever arm downward. This motion is transferred to the floater plate as a vertically upward motion and lifts the floater plate to reduce compression of the twine.  
         [0035]    [0035]FIG. 12 shows attachment of the present twine tensioner  23  (or  23 A or  23 B) to an existing baler  20 C. The baler  20 C includes an existing mechanically-adjustable twine tensioner  77 C, which is adjusted to a minimum force condition (i.e. no-tension). The twine  22 C is extended from the twine dispenser  21 C through the existing twine tensioner  77 C and through the present inventive twine tensioner  23 . The twine  22 C is further extended through an existing twine guide  78 C, through a directional twine tube  79 C to a location adjacent the accumulator chamber (under which the pickup feeder  80 C is located). The newly formed rolled bale, located in the accumulator chamber generally above the pickup reel, is rolled and a loose end of the twine  22 C is positioned adjacent the rolling bale until the twine is grabbed by the bale. The twine tensioner  23  is then moved to a twine-tensioning position as the bale is further rolled and the twine is wrapped around the bale.  
         [0036]    In the foregoing description, it will be readily appreciated by persons skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.