Abstract:
A twine tensioning system for a baler in which adjacent lengths of upper and lower twine lengths are knotted and passed around a bale that is being compressed in a baler. Knots are formed to connect twine at the forward and rearward end of the bales. A slack arm maintains tension during the process of knotting and severing the twines and a stop bar is removably positioned to provide a lower stop for the slack arm when the bales are being passed through the system to minimize wear.

Description:
FIELD OF THE INVENTION 
     The present invention relates to crop balers, and, more particularly, to tensioning systems used to tie the bales as a crop is harvested. 
     BACKGROUND OF THE INVENTION 
     It has long been known that in rectangular balers, severed crop material is picked up off the ground and packed into fakes and then fed into the path of a plunger. It is then fed into a baling chamber in which succeeding flakes of crop material are compressed and pushed through the chamber to produce a bale having dimensions that are set by the cress section of the baling chamber and by appropriate length controlling mechanisms. The flakes making up the hales are tied with one or more circumferential lengths of twine to keep the hale together after the bale is ejected from the bale forming chamber. Typically, a plurality of strands of twine are passed around laterally spaced portions of the hale according to the size of the chamber. The baling twine tensioning systems have developed over the years and generally are formed with an upper and lower twine supply which is fed to a system for tying knot between two lengths of twine at the beginning and the end of the bale. Over the years, these systems have been developed so that the correct amount of tension is provided, to securely hold the bale together. One of the key elements in such a system is a slack arm which takes up the slack during the knotting process. Previous systems have provided a torturous path around one of the pivotal shafts for mechanism involved in the knotting and twine severing operation. Such a path has resulted in long term issues with respect to twine life. 
     What is needed in the art therefore is a system in which the twine path in a tensioning system provides minimal wear to the twine. 
     SUMMARY 
     A twine tensioning system is provided for a baler which includes a housing, a twine bin, and a tensioner through which twine is fed. A slack arm is pivotally mounted in the housing with the slack arm having a guide at an end remote from the pivotal connection for guiding twine. A knot tying and twine severing apparatus is positioned adjacent the remote end of the slack arm. A tucker finger is positioned below the knot tying and twine severing apparatus and is pivotally mounted on a tucker finger shaft for periodically displacing twine into the knot tying and twine severing apparatus. The slack arm is pivotally mounted to the housing above the knot tying and twine severing apparatus and a removable stop bar is secured to the housing for limiting the downward pivoting of the slack arm relative to the knot tying and twine severing apparatus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a side view of a twine tensioning system for a baler which embodies the present invention; 
         FIG. 2  is a perspective view of a stop bar incorporated in the twine tensioning apparatus of  FIG. 1 ; and, 
         FIG. 3  is a perspective view of an alternate stop bar incorporated in the twine tensioning apparatus of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     Referring now to the drawings, and more particularly to  FIG. 1 , there is illustrated a twine tensioning system  10  which is a part of an overall apparatus that traverses a field that gathers severed crop material for a bale chamber located below the illustrated twine tensioning system  10 . Details of the mechanism for severing, gathering and compressing the bales are omitted to enable a clearer understanding of the present invention. Suffice to say the path of the bale produced in the baler is from left to right in  FIG. 1 . The tension system includes a housing  12  which is generally a sheet-like frame surrounding the mechanism and providing mounting for the fixed and articulated components of the assembly. Included outside the housing  12  is an appropriate storage space  14  for halls or twine. Twine balls are stored in twine boxes (not shown) on the side of the baler. As illustrated, there are multiple eyelets or twine guides  15 , each for a separate length of twine  16  which is fed through the mechanism. Although three twine guides  15  are shown, it should be understood that any number may be employed. The storage space  14  holds twine  16  and the path of one of the lengths of twine  16  will be described, it being understood that for a plurality of twine there would be adjacent and multiple paths. 
     Upon entering the housing  12 , the twine  16  first passes through a twine tensioner  18  which has also been developed over many years. Accordingly, the details of the twine tensioner are not described to simplify an understanding of the present invention. The tensioner  18  is positioned in the system so as to provide an appropriate amount of tension as the upper and lower lengths of twine  16  are carried by the forward edge of a bale through the machine. The twine  16  then passes through a slack arm  20  which is pivotally mounted to housing  12  at pivotal point  22  and has a remote end  24  journaling a guide illustrated in the form of a pulley  26  over which the twine  16  extends. However, other slack arm designs may have an eyelet on the end. From there, the twine  16  extends to a lower pulley  28  and along beneath the lower end of frame  12  and around a bale  30 , a portion of which is illustrated. 
     Mounted within housing  12  is a knot tying and twine severing apparatus  32  which has a central rotational axis  34 . As illustrated, the rotational axis  34  is positioned below the pivotal axis  22  of the slack arm  20 . However, the rotational axis  34  does not need to be positioned beneath the pivotal axis  22 . It may be inline with, or above pivotal axis  22 , used on the knotter table layout. The knot tying and twine severing apparatus  32  also has been developed over the years and the details are omitted to gain clearer understanding of the present invention. Suffice to say that the mechanism  32  ties a knot between upper and lower lengths of twine  16  and generates two knots, one of which is at the forward end of the current bale  30  and the other of which is at the end of the next bale  30 . A knife in the knotter (not shown) cuts the twine  18  to release the knot from the twine leading to the twine balls. 
     A tucker finger  36  is positioned within housing  12  and is mounted relative to a tucker finger shaft  38  positioned adjacent the knot tying and twine severing apparatus  32 . The tucker finger shaft  38  in previous designs was utilized as a guide for twine so that twine would pass underneath the tucker finger shaft and then around the pulley  26  of the slack arm  20 . Such a routing induced greater wear in the shaft itself and subsequent fraying of the twine. 
     In accordance with the present invention, a stop bar  40  provides a less circuitous path and one in which minimal wear is induced on the tucker finger shaft  38 . As illustrated particularly in  FIG. 2 , the stop bar  40  includes a pair of arms  42 , each of which including a tab  44  and secured to housing  12  through removable fasteners  46 . A tube  48  is mounted at the end of arms  42  and extends in a direction parallel to the pivotal, axis of stop arm  20 . 
     It should be apparent to those skilled in the art that the stop bar may have one continuous tube which could be fixed to the outer walls of housing  12 . As shown in  FIG. 3 , the bar could also be allowed to rotate. A stop bar assembly  50  includes a tube  52  extending between and through spaced arms  54 , each having a tab  56  for removable attachment to housing  12 . The tube  52  is able to rotate relative to arms  54  and is held in place by pins  58 . 
     Thus, the stop bar  40  or  50  acts as a stop for the slack arm which is essential for maintaining proper tension in the twine passed around the bale. The stop bar  40  or  50  is easily replaceable without complexity and may be done so on site. 
     In operation, the twine  16  extends through the tensioner  18 , around the guide  26  and around the hale  30  when the bale  30  is being moved through the chamber and the twine path is in the position illustrated in  FIG. 1  in which the slack arm is resting against the stop bar  40 . The force required to pull twine  16  through the tensioner  18  is higher than the twine, force to bottom out the slack  20  arm on the stop bar  40 . This ensures that the correct tension is maintained in the twine  16 . It should be noted that the path for the twine  16  between the tensioner  18  and the guide  26  in the slack arm  20  is essentially a non-circuitous path which provides minimum wear for the twine  16 . When the knotting process is being performed, the slack arm  20  pivots upward to maintain appropriate tension and in this position there is a circuitous path around the tube  44  of the stop bar  40  but the tension at that point in the cycle is greatly reduced which minimizes wear on the tube  40  and resultant fraying. It is important to have non-circuitous paths during the operation so that pressure on circuitous joints can be minimized. With the prior arrangement the rubbing part was greatly increased and with the substantially straight line path it is minimized with an accompanying reduction in wear. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.