Abstract:
An activating portion on one section of an adjustable wheel assembly triggers a proximity switch on a vehicle such as a field sprayer to provide a signal indicative of wheel tread. The signal is sent to a controller which controls wheel tread adjustment. Two or more assemblies may be adjusted simultaneously reduce adjustment time. The operator control is located in the vehicle cab for entering wheel spacings, providing an indication of the actual spacing and individual wheel position, and providing error and warning messages. An interlock system prevents axle telescoping unless certain vehicle conditions are satisfied, such as the vehicle speed being below a preselected point and vehicle being in the field mode.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to adjustable axles for vehicles, and, more specifically, to an adjustable axle control system for wheel spacing adjustments on agricultural implements such as field sprayers. 
     BACKGROUND OF THE INVENTION 
     Adjustable axle assemblies are commonly utilized to adjust wheel spacing in agricultural vehicles for numerous reasons including the accommodation of a variety of row spacings and the following of specified wheel track patterns. Examples of such structures are shown in U.S. Pat. Nos. 6,139,045; 5,454,583; and 5,282,644. Although various devices for determining and setting axle position have been available, providing repeatable and reliable wheel spacing adjustments in a user-friendly manner with adequate interlocks to assure adjustments are made only under proper operating conditions has been a continuing source of problems. Some systems require the operator to read indicia on or adjacent the adjustable axle and are inconvenient to use. Others require each axle assembly to be adjusted separately which is a time-consuming process on vehicles having numerous axle assemblies. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved system for determining and setting axle position on a vehicle with an adjustable axle. It is a further object to provide such a system which overcomes most or all of the problems associated with previously available wheel spacing systems. 
     It is another object of the present invention to provide an improved system for determining and setting axle position on an adjustable axle vehicle which is easy to operate and which provides reliable feedback so the operator can readily determine axle adjustment and make changes in wheel spacing from the operator station of the vehicle. It is a further object to provide such a system which facilitates adjustment of two or more axle assemblies at one time to reduce the time necessary for completing the vehicle tread adjustment. 
     It is still another object of the present invention to provide a system for determining and setting axle position on an adjustable axle vehicle having an improved structure for indicating the amount of axle telescoping. It is a further object to provide such a system having an improved interlock system. 
     In the embodiment shown, a strap on the side of a telescoping axle knee includes spaced portions which trigger or activate a sensor or switch attached to the mainframe axle for each adjustable axle assembly on a vehicle such as a field sprayer. Each spaced portion represents a preselected distance of travel allowing numerous wheel tread settings between the maximum and minimum spacings. Telescoping of the assemblies is controlled by a chassis controller, and two or more assemblies may be adjusted simultaneously if desired to reduce adjustment time. The operator control is located in the vehicle cab for entering wheel spacings and includes a readout providing a convenient indication of the actual spacing and individual wheel position. The readout also provides error and warning messages. An interlock system prevents axle telescoping unless certain vehicle conditions are satisfied, such as vehicle speed below a preselected point and vehicle in the field mode. Failed sensor indications or indications that the telescoping axle fails to fully extend or retract are also provided. The control includes a reset feature for easily calibrating tread adjustment when the axles are telescoped to a limit position. The operator control is easy to understand and operate, and the readout provides a clear indication of the state of all the telescoping axle assemblies. Warning and error messages help the operator to quickly diagnose system problems. 
     These and other objects, features and advantages of the present invention will become apparent from a reading of the detailed description below in view of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic representation of the user input and display device and controller for an adjustable axle vehicle. 
         FIG. 2  is a view of a portion of an adjustable axle assembly for the vehicle showing a transducer and actuator structure for providing position signals to the controller circuit. 
         FIG. 3  is an enlarged perspective view of the telescoping portion of the axle assembly of  FIG. 2 . 
         FIGS. 4A-4D  is a controller flow chart for right front tread of the vehicle and for the tread in control. 
         FIG. 5  is a flow chart illustrating the programmed operation of the left front tread out adjustment. 
         FIG. 6  is a flow chart illustrating the programmed operation of the right rear tread out adjustment. 
         FIG. 7  is a flow chart illustrating the programmed operation of the left rear tread out adjustment. 
         FIG. 8  is a flow chart illustrating the programmed operation of the tread adjust calibration. 
         FIG. 9  is a flow chart illustrating the programmed operation for providing caution messages for tread sensor miscalibration and transport position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to  FIG. 1  therein is shown a control and display system  10  for a vehicle such as a field sprayer shown schematically on the display at  12 . The vehicle  12  includes a frame  14  supported for forward movement over the ground by left- and right-front (LF and RF) wheels  16 ,  17  and left- and right-rear (LR and RR) wheels  18 ,  19 . An operator cab  22  is supported on the frame  14  between the wheels  16 - 19 . 
     The wheels are supported by adjustable axle members  26  ( FIG. 2 ) for movement over a range of tread positions between narrowed transport positions (solid lines of  FIG. 1 ) and widely spaced positions (broken lines of  FIG. 1 ). As shown in  FIG. 2 , the member  26  includes a first tubular member  34  extending outwardly from the frame  14 , and a fabricated knee joint structure  36  supporting the corresponding wheel and having an inner tubular end telescopingly received within the member  34 . Hydraulic cylinder or motor structure  38  extending between the frame  14  and the tubular member  36  and connected to electrohydraulic valve structure  40  is extendible and retractable to move the joint structure out and in to change the wheel tread. 
     The electrohydraulic valve structure  40  for each wheel is connected to a source  42  of hydraulic fluid under pressure and includes a control input  44  connected to wheel control relay structure  46 . The relay structure  46  is connected to five low side driver outputs  48  of a main electronic controller  50  that power the individual relays of the structure  46 . The controller  50  and relay structure  46  control the valves  40  to provide hydraulic tread adjust for the four wheels  16 ,  17 ,  18  and  19  in both independently and combined sequences described in further detail below. The controller  50  includes four sensor inputs  54  which receive signals from corresponding transducers or sensors  56  located at each of the adjustable axle members  26  to determine the current position of the tread. A control input and display device  60  includes outputs  62  connected to inputs of the controller  50  to provide request signals to the controller to move the wheels  16 - 19  outwardly or inwardly. The display device  60  may be the commercially available John Deere GreenStar Display having a screen  64  with menu driven commands that allow an operator to program information quickly. The display area allows viewing of operational data while on the go and utilizes audible tones to guide or alert users while operating the machine. The display  60  has a SETUP page mode for tread readout and adjustment (shown) wherein information such as actual front and rear tread widths can be displayed and desired tread widths can be entered and displayed. Messages are displayed on a message screen  64 g. 
     The control and display device  10  includes all tread in and all tread out control switches  65  and  66  and vehicle transport range and field range control indicators or switches  67  and  68 . The transport range control switch  67  will be activated when high speed operation of the vehicle is selected. 
     An activating device  70 , shown as a single laser cut metal piece having upright raised activating portions  72  regularly spaced along the telescoping portion of a knee assembly  74 , moves with the assembly  74  within an outer beam  76  of each of the adjustable axle members  26 . The sensor  56  provides signals to the controller  50  as the axle members are adjusted in or out to vary the tread. The sensor  56  may be a proximity switch such as a hall effect transducer which senses each activating portion  72 . As the portion moves into close proximity of the sensor  56 , a pulse is provided to the input of the controller  50 . The activating portions  72  represent a fixed axle travel distance, for example, one inch, so each pulse represents a predetermined tread increment. Wheel spacing for a pair of front or rear axle members  26  therefore may be determined by:
 
Tread=W s +(S×N (Left) )+(S×N (Right) )
 
where W s  is the initial minimum tread, S is the spacing between the activating portions  72 , and N (Left)  is the number of pulses provided by the left transducer  56  and N (Right)  is the number of pulses to the input  54  of the controller  50  as the axle members  26  are adjusted outwardly. For example, a field sprayer may have tread settings at 115 inches for transport, and (120+(S×N (Left) )+(S×N (Right) )) inches from 120 inches up to 160 inches total tread setting. An elongated slot at  78  provides a longer first increment (2.5 inches for the above example).
 
     The controller  50  controls the hydraulic tread adjust of the four axle members in both independent and combined sequences. In one arrangement, the user can adjust the tread of any of the four wheels using the SETUP page of the display device  60 . Each wheel  16 - 19  is movable outwardly independently of the other wheels, but all four wheels will move inwardly at the same time under the operation of the controller  50  and the valve structure  40 . 
     Referring to  FIGS. 4-9 , therein are shown flow charts for the programmed operation of the controller  50 . Upon startup  200  and first power up  202  the initial position settings are set to zero at  204 . If a startup/reboot is determined at  206 , the previous tread adjustments values are read from a non-volatile memory into the random access memory of the controller  50  at  208 . 
     After the initialization steps  200 - 208 , the tread out switch  65  is checked at  210 , and if the switch  65  is active, the tread in valve control is turned off at  212 , and vehicle speed and the condition of the control switches  67  and  68  are checked at  214  ( FIG. 4C ) before initiating any tread out movement of the assemblies  26 . If the conditions of the switches  67  and  68  indicates the vehicle is operating in the transport mode, or if the vehicle speed is above a preselected maximum speed set for outward wheel adjustment (5 MPH), the device  10  displays a message informing the operator that the vehicle speed must be below the preselected speed and the vehicle must be in the field mode at  216 . Control is then returned to  210  ( FIG. 4A ). 
     If the all tread out switch  65  is not active at  210 , the all tread in switch  66  is polled at  220 . If both the switches  65  and  66  are inactive, the switches are continually polled ( 210 ,  220 ) until one of the switches is activated. Upon activation of the all tread in switch  66 , the valves controlling tread extension for the four assemblies  26  are immediately shut off at  222  and vehicle speed and vehicle mode are checked at  224 . If transport mode operation or vehicle speed greater the preselected minimum speed is determined at  224 , the device  10  displays the message informing the operator that the vehicle speed must be below the preselected speed and the vehicle must be in the field mode at  226  to adjust the tread, and control is again returned to  210 . 
     Once the controller determines vehicle operating conditions are satisfactory for initiating wheel tread in adjustments at  224 , the position of the right front wheel assembly  26  is checked at  230  to determine if right front position is at the fully in or zero position, and, if so, the remaining wheel assemblies  26  are checked for fully in conditions at  232 . If all the remaining wheel assemblies have been fully in longer than a preselected time (0.2 seconds), the device  10  displays an all tread in completion message at  234  and control is returned to  210 . If all the assemblies are not fully retracted at  232 , control is again returned to  210 . 
     If the right front position is greater than zero at  230 , the all tread in valves are activated at  238 , and if the right front tread sensor  56  has detected an activating portion  72  causing a low to high transition at the controller input  54  ( 240 ), the right front position indication is decreased. The decrease in the spacing indication will be S(=1 inch) unless the current indication less than 1.5 inches and the sensor  56  is adjacent the elongated slot  78 . In that event, the decrease will be 1.5 inches resulting in a right front indication of zero. The present position and width indications are then updated on the display device  60  at  244  and  246 . After the position update at  242 , or if there has been no low to high transition at the right front sensor at  240 , the remaining sensors are checked in turn ( 250 ,  260 , and  270 ) and positions are decreased if necessary ( 252 ,  262  and  272 ). The display device  60  is updated ( 254 ,  256 ;  264 ,  266 ; and  274 ,  276 ) in similar fashion for each remaining wheel assembly. Thereafter control is again returned to  210 . 
     Assuming that the operator activates the all tread out switch ( 210  of  FIG. 4A ), the all tread in valves are shut off at  212  and vehicle speed and operation mode are checked at  214  ( FIG. 4C ). If speed is below the preselected speed and if the vehicle is not in the transport mode of operation, the tread out control of  FIGS. 4C-4D  and  FIGS. 5-7  is initiated. The right front position is compared at  300  with the target right front position entered into the device  60  ( FIG. 4C ). If the actual position is less than target, the right front tread out valve is activated at  302  and the output of the right front sensor  56  is checked for a low to high transition since the last check. ( 304  of FIG  4 D). If such a transition has occurred, the right front position indication is increased one increment (one inch unless the present position is zero or the fully retracted position so that the initial low-high transition at the area  78  indicates a movement of 1.5 inches). The position indication on the display  60  is updated at  308 . Control is returned to  210  after the update at  308  or if there has been no transition detected at  304 , and the process is repeated. Once the right front position reaches or exceeds the target position for a preselected period of lime ( 300  and  310  of  FIG. 4C ), the right front tread out valve is turned off at  312 , and if the remaining wheel assembly positions are at or above their target positions for the preselected time at  314 , a tread out completion message is provided on the display  64 g and control is returned to  210 . 
     The left front, right rear and left rear tread out control operations of  FIGS. 5-7  are carried out simultaneously with the steps  300 - 316  of  FIGS. 4C and 4D  described above. Once the predetermined vehicle conditions are determined at  214 , the target positions are compared with actual positions for the left front ( 400  of  FIG. 5 ), the right rear ( 500  of  FIG. 6 ), and the left rear ( 600  of  FIG. 7 ). The control operations of  FIGS. 5-7  are generally identical for each tread so only the left front tread out routine will be described in detail. 
     If the position determined at  400  is less than the target position indicating that the corresponding cylinder structure  38  needs to move the left front wheel outwardly, the left front valve is turned on at  402  and the controller checks for a recent sensor transition from low to high at  404 . If there has been no transition, control is returned to  210  and the process begins again. However, if there has been a low to high transition since the last check, the left front position is incremented by one unit (one inch unless the present position is zero or the fully retracted position so that the initial low-high transition at the area  78  indicates a movement of 1.5 inches) at  406 . The left front position is displayed at  408 , the total front width is displayed at  409 , and control is returned to  210 . The right and left rear tread out control of  FIGS. 6 and 7  include steps  500 ,  502 ,  504 ,  506 ,  508 ,  509 ,  510 ,  512  and  600 ,  602 ,  604   606 ,  608 ,  610 ,  612 , respectively, generally identical to  400 - 412  described above. Once the wheel assembly positions are all at or above their target positions for the preselected time at  314  ( FIG. 4D ), a tread out completion message is provided on the display  64 g and control is returned to  210 . 
     When the operator is finished with a field, the all tread in switch  66  is activated and, provided the proper vehicle conditions are present, the controller  50  activates the relay and valve structure to telescope the knee joint structures  36  inwardly relative to the corresponding tubes  34  until the controller determines that the wheel tread is al the preselected minimum value. After transport, the all tread out switch  65  is activated, and the controller  50  causes the wheels to move outwardly, if the preselected vehicle conditions are met, until the desired spacings set on the device  60  are reached. 
     The device  60  also includes a calibration page, and a calibration routine is initiated at  700  of  FIG. 8  when the page is selected. A calibrate instruction message is provided at on the display  64 g ( 702 ) with selection of the calibration page. The operator returns the treads to the minimum settings. The outermost end ( 78 e of  FIG. 3 ) of the activation device  70  will be adjacent the sensor  56  when the tread is minimized, and the sensor outputs are checked al  704  to see if the outputs are all high. If all sensor outputs are high, tread positions are set to zero at  706  and a calibration completed message is provided on the display  64 g ( 708 ). Thereafter, the calibration complete message remains displayed until the page is changed on the display device  60  or the key F is pressed on the device ( 710 ) to return control to  702 . If the key F is depressed, the calibration message at  702  is again displayed and the calibration routine begins again. If all sensor outputs are not high at  704 , either the tread is not at the innermost position or a tread sensor  56  has failed and corresponding message is provide to the operator at  712 . The message remains until the key F is pressed at  714 . 
       FIG. 9  shows a flow chart illustrating the programmed operation for providing caution messages for tread sensor miscalibration and transport position. The routine of  FIG. 9  runs continually after startup and checks each wheel position at  800 ,  802 ,  804  and  806 . If any of the tread positions indicate a reading less than the minimum tread, a caution message is provided for the corresponding position at  810 ,  812 ,  814  or  816  and a fault message indication is sent ( 820 ,  822 ,  824  or  826 ) for that position. After all positions are checked, the selected transport speed range is checked at  830 . If the transport range switch  67  is not active, control is returned to  800 . If the transport speed range is selected, the tread positions are checked at  832 . If all tread positions are not in the narrow position, a caution message is displayed at  834  and a fault message indication is provided at  836 . 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.