Abstract:
A cane harvester including a support member and a basecutter assembly carried by the support member. The basecutter assembly includes a plurality of basecutter units and a control system. The plurality of basecutter units include first and second basecutter units. The first basecutter unit has a first set of blades and the second basecutter has a second set of blades. The first set of blades are rotatable by the first basecutter unit, and the second set of blades are rotatable by the second basecutter unit. The control system is configured to synchronize the first set of blades with the second set of blades.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/921,950, entitled “BASECUTTER BLADE CONTROL FOR A CANE HARVESTER”, filed Dec. 30, 2013, which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to cane harvesters, and, more particularly, to basecutter assemblies used in cane harvesters. 
     2. Description of the Related Art 
     Sugarcane and  sorghum  are two types of stalk-like crops that are commercially grown. Other cane-like crops, such as  miscanthus , energy cane, and giant reed, have received attention as a form of bio-energy. During the harvesting of cane, often the top of the plant is cut off with a separate cutter head. The top portion of the plant may be allowed to simply fall to the ground, or seeds therein may be gathered by the harvester. 
       Sorghum  is a major grain crop and the cane of  sorghum  is used for sugar products.  Sorghum  is one of the oldest known crops and is used as a staple food in many parts of the world. 
     Sugarcane is native to temperate to tropical regions, the cane has stout, jointed, fibrous stalks that are rich in sugar and measure six to nineteen feet tall. Once sugarcane is planted, a stand can be harvested several times. After each harvest, the cane sends up new stalks called rattons. Each successive harvest produces a decreasing yield, eventually leading to a needed replanting operation. 
     The harvesting of sugarcane includes the cutting of the cane at the base of the stalk, stripping the leaves, chopping the cane into consistent lengths, and depositing the cane into a transporting device. The harvester typically blows the leaves and such back onto the ground. 
     Sugarcane harvesting machines utilize a basecutter device that is integral with the main frame of the machine. The height of the cut is regulated by the raising and lowering of the main portion of the machine or of the basecutter assembly. 
     Sugarcane harvesting or cut operations require a certain degree of precision for good crop yield. Ideally, the cut height should be substantially close to the surface of the ground so as to harvest the optimal crop without damage to the equipment and at minimal cost. 
     The market is demanding the crop harvesting of multiple rows of cane to compensate for areas with low yield and to improve performance relative to energy usage. If the cane harvester design needs to increase the disc diameter this results in a gearbox being heavier, bigger, more expensive and limiting to the design freedom of the harvester. 
     What is needed in the art is a way to effectively eliminate the gearbox, to reduce the weight and the size needed for the basecutter assembly. 
     SUMMARY OF THE INVENTION 
     The present invention provides an inventive control of basecutter units to enhance cane harvesting. 
     The invention in one form is directed to a cane harvester including a support member and a basecutter assembly carried by the support member. The basecutter assembly includes a plurality of basecutter units and a control system. The plurality of basecutter units include first and second basecutter units. The first basecutter unit has a first set of blades and the second basecutter has a second set of blades. The first set of blades are rotatable by the first basecutter unit, and the second set of blades are rotatable by the second basecutter unit. The control system is configured to synchronize the first set of blades with the second set of blades. 
     The invention in another form is directed to a basecutter assembly for use in a cane harvester. The basecutter assembly includes a plurality of basecutter units and a control system. The plurality of basecutter units include first and second basecutter units. The first basecutter unit has a first set of blades and the second basecutter has a second set of blades. The first set of blades are rotatable by the first basecutter unit, and the second set of blades are rotatable by the second basecutter unit. The control system is configured to synchronize the first set of blades with the second set of blades. 
     The invention in yet another form is directed to a method of controlling a basecutter assembly used in a cane harvester. The method includes the steps of rotating a first set of blades of a first basecutter unit, rotating a second set of blades of a second basecutter unit and a synchronizing step. The synchronizing step includes the synchronizing of the first set of blades with the second set of blades using a control system. 
     An advantage of the present invention is that the sugarcane harvester does not need the weight and mechanical linkages of a gearbox to synchronize basecutter blades. 
     Another advantage is that the present invention allows design flexibility of the harvester. 
    
    
     
       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 partial side view depicting, partly in representational form, a sugarcane harvester having an embodiment of a basecutter assembly constructed in accordance with the present invention; 
         FIG. 2  is a schematical view of a basecutter assembly used in the cane harvester of  FIG. 1 ; and 
         FIG. 3  is a state diagram that illustrates how part of the inventive control system of  FIG. 2  works. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIG. 1 , there is shown a cane harvester  10 , which generally includes a chassis  12 , a cab  14 , a topper  16 , a basecutter assembly  18 , a pair of front wheels  20  and a pair of rear wheels  22 , upon a ground surface  24 . A support member  26  couples basecutter assembly  18  to chassis  12 . 
     Although sugarcane harvester  10  is depicted having wheels  20  and  22 , it will be appreciated that tracks or other support mechanisms could be equally as well employed and are not considered critical to the present invention or its practice. 
     Now, additionally referring to  FIGS. 2 and 3 , there is shown additional details of basecutter assembly  18 . Basecutter assembly  18  is shown in  FIG. 1  as being connected to chassis  12  by way of support member  26 . In the preferred embodiment depicted, basecutter assembly  18  includes a basecutter unit  28  and a basecutter unit  30  configured to function in a counter-rotating manner. Basecutter units  28  and  30  are each respectively driven by separate hydraulic motors  38  and  40 , which are respectively operatively coupled to drive rotary cutter discs  34  and  34 ′ that are respectively equipped with blades  36  and  36 ′. Hydraulic motors  38  and  40  are operatively connected to a hydraulic pump  54 , typically positioned proximate to the engine of harvester  10 . 
     Basecutter assembly  18  includes a control system  42  that controls the operation of basecutter units  28  and  30 . Control system  42  includes a controller  44 , sensors  46  and  48 , and valves  50  and  52 . Controller  44  may be a standalone controller or the functions herein attributed to controller  44  may be carried out by some other controller that is a part of cane harvester  10 . The diagram of  FIG. 2 , discussed in more detail later, can also be thought of as being symbolic and it is contemplated that the hydraulic connections of motors  48  and  40  may be in a parallel fashion as an alternative to the serial connection shown. However, the serial connection as depicted reflects the preferred embodiment of the present invention. 
     Sensors  46  and  48  provide signals with position information relative to the position of blades  36  and  36 ′ to controller  44 . Sensors  46  and  48  sense a position of a rotating component, relative to time, in motors  38  and  40 , a position of a rotating shaft, a position of disks  34  and  34 ′ and/or a position of individual blades  36  and  36 ′. The information ultimately relates to the position of blades  36  and  36 ′ regardless of which moving component that sensors  46  and  48  are sensing the position thereof. When basecutter assembly  18  is engaged, by way of a command to controller  44  by way of a user interface (not shown) or some other device sending a command to controller  44 , then motors  38  and  40  are activated by turning pump  54  on and positioning valves  50  and  52  so that hydraulic fluid is directed to motors  38  and  40 . Pressurized hydraulic fluid is controllably sent to motors  38  and  40  so that blades  36  and  36 ′ are synchronized with each other, so that as blades  36  and  36 ′ counter-rotate relative to each other they do not come into contact with each other. 
     A method  100  is illustrated in  FIG. 3 , where input from sensors  46  and  48  is detected at step  102 . If both signals are present then method  100  proceeds to step  104 , where the two signals are compared to see if the signals are of a pre-selected phase relative to each other. It is understood that the location of the sensors may be offset such that if the phase of the signals are in phase that blades  36  and  36 ′ are sequenced to move such that as they pass at their closest approach to each other that they are substantially equidistant to/from a preceding or succeeding blade on the opposite disk  34 ,  34 ′. For purposes of discussion hereafter, it will be assumed that sensors  46  and  48  are placed at similar locations on both of basecutter units  28  and  30 . This then would mean that when the signals are in phase that a blade  36  of basecutter unit  28  would be pointed at a blade  36 ′ of basecutter unit  30 , which can be an interfering situation. Another way to think of this arrangement is if the signals and basecutter units  28  and  30  are in phase the blade positions and movement would be a mirror image of each other. 
     To interleave blades  36  with blades  36 ′ to prevent interference then the phase relationship of the signals need to be held ideally at a maximum, or opposite phase. Control system  42  sends signals to valves  50  and  52  to control the speed of motors  38  and  40 , at step  108 , so that there is a substantially fixed phase relationship with the signals. This fixed relationship is an out of phase relationship and more specifically an opposite phase relationship. 
     More specifically, control system  42  sends signals to valves  50  and  52  to control the speed of motors  38  and  40  so that there is a substantially fixed phase relationship between blades  36  and blades  36 ′. This fixed relationship is an out of phase relationship and more specifically an opposite phase relationship of blades  36  and  36 ′. 
     If only one signal, or no signal, is detected at step  102  then pump  54  is stopped at step  106 . Controller  44  may operate method  100  using a phase-locked loop system, where either of the signals can be considered a reference signal. However, in the present invention either signal or both signals can be affected by controller  44  in order to maintain the desired phase relationship between blades  36  and blades  36 ′. 
     In the present invention a closed hydraulic circuit can be used with independent fixed displacement hydraulic motors  38  and  40  connected in series to move cutter discs  34  and  34 ′ in opposite rotational directions in order to feed the cane stalks into the throat of cane harvester  10 . Valves  50  and  52  are electro-proportional flow control valves  50  and  52  that allow the diversion of part of the flow to reduce the shaft rpm, under the control of controller  44 , to correct the phase relationship of the signals and thus the phase relationship of blades  36  and  36 ′. At each basecutter unit  38  and  40 , sensors  46  and  48  detect the position and speed, and send signals to controller  44 , which process the information of the signals and uses a control algorithm to activate flow control valves  50  and  52  that are respectively related to motors  38  and  40  in order to maintain a selected phase relationship of blades  36  and  36 ′. If for any reason one basecutter unit  28  or  30  gets blocked due to stones or other material, the serial relationship of the hydraulic circuit has a tendency to also stop the other basecutter unit. Such a stoppage will result in the signals indicating no positional change and a stop pump command  106  is issued to pump  54 . 
     In the mechanical assembly of basecutter assembly  18  blades  36  and  36 ′ are synchronized and then the signals of sensors  46  and  48  are continuously compared to ensure that the signals have the selected phase relationship. When a difference in the phase relationship is detected control system  42  generates a command to the appropriate valve  50  or  52  to reduce the speed of one of the basecutter units  28  or  30 , in order to adjust the speed and as a consequence the re-phasing of blades  36  and  36 ′. Control system  42  when needed can also act to increase the speed of one basecutter unit  28  or  30  to also re-phase blades  36  and  36 ′. Control system  42  can also act to increase the speed of one basecutter unit  28  or  30  and decrease the speed of the other basecutter unit  28  or  30  to accomplish the goal of keeping the phase relationship of blades  36  and  36 ′ within a desired tolerance. 
     In a typical phase-locked loop control system often a controlled oscillator establishes the reference signal and an item under control produces a signal that is then used to compare to the reference signal. Then the control system adjusts some aspect of the item under control so that the signal from the item under control is in a phase-locked situation with the reference signal. However, in the present invention it can be understood that one of the signals from sensors  46  or  48  serves as a reference signal. Another way of looking at this is that both signals can serve as reference signals with control system  42  deciding which motor, or whether both motors need control adjustments. Control system  42  can consider the amount of remaining adjustment in flow control valves  50  and  52  to decide which valve to adjust, so in this sense, the signal from sensor  46  or  48  of the other basecutter unit  28  or  30  becomes the reference signal. 
     Advantageously, the present invention increases or decreases the speed of basecutter units  28  and  30  so that the blade rotation remains synchronized. Another advantage is that larger cutting profiles are possible without adding the weight and taking the space of a gearbox. 
     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.