Abstract:
This invention pertains to a method for securing twines or strings made of natural or synthetic fibers into tightly wrapped closed loops around bales, boxes or other objects. It applies the knotting effect of twines, when under proper tension are twisted together into overlapping multiple strands.

Description:
BACKGROUND OF THE INVENTION 
     Twines made of natural or synthetic fibers are commonly used to tie loose fibrous substances, such as hay and straw into bales for handling and transportation. The tying process of hay balers is automatic, placing twines around the bale in loops, and tying the two ends of each looped twine into knots. The tying methods applied in the currently available baling apparatuses produce loose loops, allowing the expansion of the bales, thereby reducing the final density of the baled substance. 
     For improved performance of the baling apparatuses, a better tying method is needed, which can produce tightly wrapped loops, not allowing the expansion of the bale after its release from the compressive forces of the baling apparatus. 
     The currently marketed tying apparatuses have complex mechanism, requiring frequent adjustments, and calling for rather exact control of the tension in the twine for proper function. 
     The complexity of the currently marketed tying apparatuses substantially increases the price of the balers. Simpler and less costly tying mechanism is most desirable. 
     The aim of my invention is to satisfy the above requirements. 
     SUMMARY OF THE INVENTION 
     My invention applies the knotting effect of twines, made of natural or synthetic fibers, when placed around an object in loops with sufficient length. Two cut ended strands are twisted together, under proper tension, into single, overlapping multi-strandad configuration, forming tightly wrapped closed loops. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1a-d are schematic diagrams illustrating the subsequent stages of the twist tying process of a twine. 
     FIGS. 2a and 2b illustrate the general arrangement of the twine around a bale. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The tying process of this invention is as follows: The twine with sufficient length is placed around the object, such as a bale, to form a loop. Its two cut ended single strands are received by the twine twisting mechanism, which applies twisting action on the two converging strands, twisting them together into a single, double-strandad configuration, forming a closed loop around the object. In the first phase of the twisting action the two single strands begin to form a twisted double strand at the twisting mechanism, gradually advancing the twisting action toward the object, thereby tightening the loop around the object. Simultaneously, the angle between the two single strands, as those depart from the object and converge into a double strand, increases. The twisting action reduces the length of the strands between the object and the twisting mechanism, which is compensated for by allowing the corresponding movement of the twisting mechanism toward the object, against controlled resistive forces, thereby maintaining the necessary tension for the proper formation of the twisted strands. 
     The second phase of the twisting process begins when the angle between the two converging single strands of the twine approaches 180 degrees, at which time an overlapping twisting action begins, first winding one of the two converging single strands on top of the already formed double strand, beginning at the point where the two single strands converge into the twisted doublestrand, pulling and bending the double stranded twine toward the single strand which is being overlappingly twisted around the double stranded twine. As the angle between the single strand and the double strand decreases, while the twisting action continues, they become twisted together into a triple strand. The direction or sense of the winding of the single strand on top of the double strand is opposite to the direction or sense of the twisting of two single strands into a double strand. The reversal of the direction of the winding produces a locking effect on the strands of the twine, preventing the unwinding of the twisted strands under the action of the tensil forces in the looped twine. While the formation of the triple strand occures, the tension in the two single strands around the object increases, pulling the triple stranded twine against the body of the object, thereby producing an additional locking effect against the reversal of the twisting action by the tensil forces in the twine after releasing the twines from the twisting mechanism. During both the first and the second phases of the twisting action the twisting mechanism is allowed to follow the changes in the length of the strands of the twine, while maintaining the necessary tension in the strands for proper twisting action. Under the action of the increasing torsional forces a coiled configuration developes in the portion of the double-strandad twine not twisted into the triple strand. This coiling effect further improves the knotting of the looped twine, as the large diameter of the coiled double strandad twine does not allow it to pass through between the object and the tightly held single strands of the twine forming the loop around the object. 
     After completing the tightly wrapped closed loop, and at a preset tension in the twisted strands, the twisting mechanism automatically releases the twine. 
     In the continuous operation of a baling apparatus, putting more than one loop of the twine around each bale, each loop is made separately by a twisting unit. The twines are held across the path of the bale, as it is being formed, and the loops around the bale are completed by the use of movable needles, which after the bale reaches the desired length deliver the twines from the twines storage container to the twisting mechanism. Each loop of the twine is held by a separate twisting unit of the mechanism. After the delivery of the twines by the needles the twine twisting mechanism firmly hold the twines in closed loops around the bale, the needles return to their home positions. During the twisting process the twisting mechanism is pulled toward the bale by the twisted strands. At the completion of the process the ends of the twisted strands are pulled free from the twisting mechanism and under the action of the applied forces the twisting mechanisms return to their home positions for tying the next bale. 
     In the first stage, shown of FIG. 1a, the formation of the twisted double strand configuration 4, of the two cut ended single strands 3a and 3b of the twine begins. 
     The second stage is illustrated on FIG. 1b, when under the continued twisting action on the double strand 4, the angle between the strands 3a and 3b approaches 180 degrees, as the tension in the twine increases. The interaction between the increasing angle and the increasing tension in the two strands of the twine, cause the pulling of the double strand 4 toward the single strand 3b, resulting in the overlapping winding 5 of the double strand 4 and the single strand 3b into a triple strand 6, the direction or sense of which is opposite to that of the double strand 4. The stage is illustrated on FIG. 1c. 
     FIG. 1d, illustrates the final stage of the process when under the increasing torsional forces on the double strand 4, and with the increasing tension in the strands 3a and 3b, the coiling configuration 7 of the double strand developes, pulling the strands of the twine free from the holding element of the twisting mechanism. 
     FIGS. 2a and 2b illustrate the general arrangement of the twine around a bale 1, and the relative positions of the twine twisting mechanism 2, at the beginning and at the end of the tying process. In FIG. 2a the twine is formed into a loose loop around the bale, as the two cut ended strands 3a and 3b are held by the twine twisting mechanism 2, which exerts the twisting action on the two strands 3a and 3b. At the conclusion of the tying process the twisting mechanism 2 is pulled toward the bale where the twines are relased.