Abstract:
A method and apparatus for automatically controlling a header lift system of an agricultural harvesting machine, particularly a windrower, to put a header of the machine into a transport mode wherein the header is raised to an elevated transport position, under certain specific conditions. Such conditions can include, but are not limited to, the machine operating in a high-speed range, the header not operating, the speed of the machine being above a predetermined level, and the last inputted control command being a header raise command. When in the transport mode, the lift system can also be operated in a float mode. Further, the header lift system can be returned to a normal mode when certain criteria are present for doing so.

Description:
[0001]     This application is a Continuation-In-Part of co-pending U.S. patent application Ser. No. 10/822,465, filed Apr. 12, 2004; and claims priority to U.S. Provisional Application No. 60/699,271, filed Jul. 14, 2005; and U.S. Provisional Application No. 60/699,548, filed Jul. 15, 2005. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention relates to agricultural windrowers and, more particularly, to a method embodied in a software program for automatically controlling the hydraulics to put the header of a windrower into the transport mode under certain specific conditions.  
       BACKGROUND OF THE INVENTION  
       [0003]     U.S. Pat. No. 6,901,729; U.S. patent application Ser. No. 10/822,465, filed Apr. 12, 2004; U.S. Provisional Application No. 60/699,271, filed Jul. 14, 2005; and U.S. Provisional Application No. 60/699,548, filed Jul. 15, 2005, are each incorporated herein by reference in its entirety.  
         [0004]     The present invention relates generally to harvesting machines of the type that require flotation systems for permitting their headers to ride lightly up and over rises in the terrain during field operation, and particularly to a hydraulic header lift and flotation system for such a machine that will provide the dual functions of header lift and flotation.  
         [0005]     Header flotation systems typically use extension springs, either hydraulically or manually adjusted, bell cranks and other linkages to provide the desired function. The structure generally requires numerous components and large extension springs, and it is quite difficult to develop the mechanical components required to float the broad range of header sizes available even requiring different tractors or frames having their own flotation systems designed to meet their own particular header weight requirements.  
         [0006]     Some manufacturers are using an accumulator and hydraulic cylinders to perform the flotation function. These machines typically use separate hydraulic cylinders for the lift and flotation functions, and they lack the capability of independently adjusting the flotation force for each side of the header. Additionally, some headers are not inherently balanced side to side. Special considerations must be made to float and lift these headers evenly by adding ballast, which can become unreasonably heavy or awkward, or modifying the lift geometry of one side.  
         [0007]     It would be quite beneficial to have a header lift and flotation system that employs a single hydraulic cylinder for each side of the header, simplifying the controls and mechanical components necessary to perform these functions. It would also be beneficial to have an automatic capability for controlling the hydraulics to put the header of a windrower into a raised transport mode under certain specific conditions.  
       SUMMARY OF THE DISCLOSURE  
       [0008]     Accordingly, it is an object of the present invention is to provide a hydraulic lift and flotation system for the header of a crop harvesting machine that employs a single hydraulic cylinder for each side of the header.  
         [0009]     Another object of the present invention is to provide a hydraulic lift and flotation system to be used with both heavy and light headers/conditioners, i.e., a broad range of header sizes and weights.  
         [0010]     It is another object of the instant invention to provide a more simplified structure that presents greater flexibility in locating the accumulator as opposed to extension springs and necessary linkages, with fewer pivot points to wear and fewer parts to manufacture and assemble.  
         [0011]     It is still another object of the instant invention to provide a flotation and lift system that requires no dealer or customer assembly.  
         [0012]     It is an even still further object of the instant invention to provide a hydraulic header flotation and lift system that reduces hydraulic and mechanical shock loading when raising the header in a less than fully raised position, improving the ride comfort for the operator and improving hydraulic and structural durability of the harvester.  
         [0013]     It is yet another object of this invention to provide an improved hydraulic header lift and flotation system that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use.  
         [0014]     It is still yet another object of this invention to have an automatic capability for controlling the hydraulics to put the header of a windrower into a raised transport mode under certain specific conditions. Another object is to have a capability to automatically put the header in a float mode when in the transport mode. And, another object is to have a capability to return the header to a normal mode when normal mode criteria are present.  
         [0015]     These and other objects are attained by providing a hydraulic lift/flotation system for the header of a crop harvesting machine. Each side of the header is supported by a single cylinder that performs both the flotation and lift functions. To accommodate unbalanced headers (center of gravity not centered between the lift arms), hydraulic oil is sent to the return side of the lift cylinder on the lighter side of the header, thus resulting in even raising, lowering and float.  
         [0016]     Specific conditions for automatic movement of the header to the transport mode can include, but are not limited to, the machine being in a high speed range; the header not operating; a ground speed of the machine above a predetermined level; and a last control command being a header raise command. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:  
         [0018]      FIG. 1  is a partial side elevational view of a crop harvesting machine of the type with which the invention may be used, also showing a simplified side view of the lift and flotation system of the instant invention; and  
         [0019]      FIG. 2  is a hydraulic schematic view of one embodiment of the hydraulic system of the instant invention;  
         [0020]      FIG. 3  is a schematic of the hydraulic, mechanical and electrical sub-systems that cooperate to produce the system of  FIGS. 1 and 2 ;  
         [0021]      FIG. 4  is a high level flow diagram illustrating steps of a preferred computer program for controlling the lift and flotation system for raising a header of the crop harvesting machine from a lowered position such as illustrated in  FIG. 1 , to an elevated transport position, according to the invention;  
         [0022]      FIG. 5  is a written listing of steps of the preferred program of the invention;  
         [0023]      FIG. 6  is a written listing of further steps of the preferred program of the invention;  
         [0024]      FIG. 7  is a written listing of still further steps of the preferred program of the invention; and  
         [0025]      FIG. 8  is a simplified front view of the machine of  FIG. 1  with the header thereof raised to the transport position by the program according to the instant invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail.  
         [0027]      FIG. 1  shows the present invention utilized in connection with a self-propelled windrower  10 ; however, it will be appreciated that the principles of the present invention are not limited to a self-propelled windrower, or to any specific type of harvesting machine.  
         [0028]     In the illustrated embodiment, the self-propelled windrower  10  comprises a tractor  12  and a header  14 , the header  14  being attached to the front end of the frame  16  or chassis of the tractor  12 . The header may be of generally any suitable construction and design, and may include not only crop-harvesting mechanisms, but also crop conditioners such as elongate rolls  15 . Such attachment of the header  14  to the frame  16  is achieved through a pair of lower arms  18  (only the left one being shown, the right being generally the same) pivoted at one end to the frame  16  and at the other end to the header  14 , as well as through a central upper link  20 . The link  20  may take the form of a single double-acting hydraulic cylinder  21  whose extension and retraction is controlled by the operator to remotely control the angle of sickle bar  22  on the lower front of the header  14 .  
         [0029]     A single lift/flotation cylinder  24  or  26 , interconnecting the lower arm  18  and the frame  16  supports each side of the header, i.e., each side of the header is supported by its own lift/flotation cylinder  24  or  26 , respectively (again, only the left one being shown in this  FIG. 1 ).  
         [0030]     More specifically, the control system accomplishes two generally separate control functions, one for the left side lift/flotation cylinder  24  and one for the right side lift/floatation cylinder  26 .  
         [0031]     Directing attention now to  FIG. 2 , the hydraulic control system for left cylinder  24  and right cylinder  26  can be seen to include an electro-hydraulic subsystem generally depicted as  30 . For convenience of assembly and operation, the majority of the components are housed in a single valve body  34  with appropriately located ports and other necessary connection devices and fixtures. A fixed displacement pump  36  moves the hydraulic fluid into subsystem  30  from reservoir  40 , through the various circuits as directed by control valves, to a single accumulator  42 , to hydraulic cylinders  24 ,  26  and back to reservoir  40  as appropriate.  
         [0032]      FIG. 3  provides a more detailed depiction of the complete control system and subsystems. The hydraulic system, as shown also in  FIG. 2 , additionally depicts the electrical control and mechanical subsystems. Importantly, this figure depicts the multi-channel programmable controller  50  which exchanges electrical signals from the float switch  52 , the PWM (pulse width modulated) solenoid  56 , the proportional pressure reducing valve, PPRV or PRV  58 , the unload/relief valve  60 , and other valves to manage the lift and flotation functions as established by the operator through the appropriate switch and shown on display  64 . PRV  58  controls the amount of flotation pressure, as set by the operator. PRV  58  is current controlled/regulated. Controller  50  is preferably of the type known as a micro-controller or embedded controller unit.  
         [0033]     The hydraulic cylinders, attached to respective ends of the header, perform both the lift and flotation functions. The lifting and floating function is achieved by coupling the lifting end of the hydraulic cylinders to each other and then to a hydraulic pump, control manifold, and accumulator. The operator sets the desired flotation force by actuating a rocker switch located on the operator&#39;s console. One switch position allows hydraulic oil to enter the accumulator (increasing the hydraulic pressure), which reduces the header contact force, or flotation force, with the ground. The other switch position allows oil to exit the accumulator (reducing the hydraulic pressure), which increases the header contact force with the ground. Once the flotation force is set, the control valves will return to this preset flotation condition whenever the float mode is selected, irrespective of subsequent header lift and lower operations.  
         [0034]     To accommodate unbalanced headers (the header center of gravity is not centered between the lift arms), hydraulic oil is applied to the return side of the lift cylinder on the lighter side of the header. The addition of a defined hydraulic pressure on the back side of the cylinder results in the same lifting pressure to be required for each side. The header will then raise, lower, and float evenly. The result is the same as changing the lift geometry or adding ballast to the header. This function is referred to as the “hydraulic counterweight”.  
         [0035]     The hydraulic oil is supplied from the hydraulic ground drive charge pump, which provides constant pressure any time the engine is running. To prevent cavitation of the charge pump during rapid changes in system volume, such as during the header lower cycle, makeup oil is supplied from the header lift pump. The operator sets the hydraulic counterweight by turning a manual control valve  66  to apply more weight (hydraulic pressure) to the light side of the header until the header raises and lowers to a level condition. If too much weight is applied, the operator simply turns the valve in the opposite direction. Once the correct setting is established, the hydraulic counterweight will not need to be readjusted during machine operation. Re-adjustment will only become necessary if the header builds up with debris or upon exchange with another header.  
         [0036]     For headers that experience severe changes in balance during normal operation, i.e., draper headers with deck-shift, an electro-hydraulic valve can be installed in place of the manual control valve. This electro-hydraulic valve is adjusted from a rocker switch on the operator&#39;s console. The operator then sets the hydraulic counterweight for each deck position. Once these values are established, the control valve will adjust automatically as the deck positions are selected.  
         [0037]     This disclosure describes a header flotation system that is referred to as “non-independent”. While other embodiments are possible, including an independent system (see the disclosure of patent application Ser. No. 10/822,465 incorporated herein in its entirety by reference) it is the non-independent embodiment that provides the best example of the type of system with which the program of the instant invention can/should be used.  
         [0038]     Directing attention to  FIG. 4 , a high level flow diagram  70  is shown illustrating steps of a preferred embodiment of the computer program for controlling the lift and flotation system for raising a header of the crop harvesting machine from a lowered position such as illustrated in  FIG. 1 , to an elevated transport position, as illustrated in  FIG. 8 , according to the instant invention. The program is used to promote improved operator and machine safety in an existing system. To promote this safety, automatically raising the header to the transport mode/position is used with the current machine. As illustrated in the flow diagram  70 , the header will automatically raise to the transport position (weight supported on the accumulators or accumulator  42 ) when certain criteria is met, i.e., when the machine is moving in the high speed range, as determined at decision block  72 ; the header is not operating, as determined at decision block  74 ; the machine speed is above a predetermined a level, for instance,  10  mph, as determined at decision block  76 ; and the last control command or push was “header raise”, as determined at the decision block  78 . The accumulator or accumulators can be switched in for operation in the float mode, as denoted at block  84 , after transport height is reached or the header can be raised through the PRV circuit (PRV  58 ), such as illustrated by block  80  and decision block  82 , thereby always using the accumulator or accumulators during the raising process. The header can be raised fully against the upper stop or held slightly away to allow cushioning in both directions. If held slightly away from, that is, below the upper stop, the header will be allowed to rise up by the slight amount. Normal mode, as denoted at block  88 , is automatically re-established from the transport mode when certain criteria is met or present, as determined at decision block  86 . Exemplary criteria are set forth in the program, as discussed below.  
         [0039]     Referring also to  FIGS. 5, 6  and  7  (see generally lines  860 - 940 ), a written listing of steps of the preferred program of the invention for raising the header to the transport position (block  80  of  FIG. 4 ), once the determinations of decision blocks  72 ,  74 ,  76  and  78  of  FIG. 4  are made. The notes on the program provide a very good explanation of the various line items and steps making up the program. The program steps are written to accommodate an independent system, but are applicable to the non-independent system of  FIG. 2 , and therefore that figure can be referred to when reading the program steps. More particularly, referring generally to lines  875 - 890 , first the pressure in the accumulator or accumulators is raised to maximum. This involves turning on solenoid B ( FIG. 2 ) to connect accumulator  42  with the pressurized hydraulic fluid condition regulated by PRV  58 . In an independent system utilizing two accumulators, this would also entail turning on a second, parallel solenoid for the other independent circuit, denoted in the program as solenoid F. PRV  58  would be programmed with a transport float pressure value. As a result, hydraulic oil from pump  36  would be directed as required through PRV  58  and the valve controlled by solenoid B to accumulator  42 , such that accumulator  42  would be pressurized to the transport float pressure value. Accumulator  42  would then be connected in fluid communication with lift/flotation cylinders  24  and  26 , by turning on solenoid C. If the system is independent, a corresponding solenoid denoted as solenoid G in the program, would be turned on, to connect the accumulator of the other independent circuit to the other respective cylinder, as indicated generally in lines  895 - 920 .  
         [0040]     The controller will then loop through blocks  84  and  86  of  FIG. 4 , testing for the criteria for returning to the normal mode, as denoted generally by lines  920 - 925 . Such criteria can include, but are not limited to, a header lower switch being pushed; a machine speed of less than 5 mph; the machine is operated in a speed range other than the high-speed range; or the header PTO is not off. Presence of any one of these criteria can cause the program to return to the normal operating state.  
         [0041]      FIG. 8  illustrates header  14  of machine  10  raised to the transport height by cylinders  24  and  26 .  
         [0042]     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.