Flotation for Agricultural Implements

Abstract

An agricultural implement has front flotation wheels with a significantly increased diameter, increasing flotation and improving rolling characteristics, especially in soft soil conditions. The implement has a frame supported on front and rear wheels. Front flotation wheels are pivotally mounted to the frame about vertical axes. A hitch tongue is pivotally attached to the frame about a vertical hitch pivot axis. A wheel control mechanism connects the front flotation wheels to the hitch tongue, and is configured such that when the hitch tongue is in a neutral position the front flotation wheels roll in the operating direction, and pivoting the hitch tongue causes the front flotation wheels to pivot in the same direction.

What is claimed is: 
     
         1 . An agricultural implement apparatus comprising:
 a frame supported on rear wheels and at least one front flotation wheel for movement along the ground in an operating travel direction, and a plurality of ground engaging tools mounted on the frame substantially equally on each side of a frame axis extending parallel to the operating travel direction;   wherein the at least one front flotation wheel is pivotally mounted to the frame about a substantially vertical wheel pivot axis;   a hitch tongue having a rear end pivotally attached to a lateral mid-point of the frame about a substantially vertical hitch pivot axis located substantially on the frame axis, and having a front end adapted for pivotal attachment to a drawbar of a towing vehicle by a substantially vertical drawbar pin;   a wheel control mechanism connecting the at least one front flotation wheel to the hitch tongue such that pivotal movement of the at least one front flotation wheel about the wheel pivot axis follows pivotal movement of the hitch tongue about the hitch pivot axis.   the wheel control mechanism configured such that when the hitch tongue is in a neutral position aligned with the frame axis, the at least one front flotation wheel is oriented to roll in the operating travel direction, and pivoting the hitch tongue about the hitch pivot axis away from the neutral position causes the at least one front flotation wheel to pivot about the wheel pivot axis.   
     
     
         2 . The apparatus of  claim 1  wherein the at least one front flotation wheel has a diameter of greater than about four feet. 
     
     
         3 . The apparatus of  claim 1  wherein the frame and ground engaging tools are configured such that when the frame is oriented perpendicular to the operating travel direction, the ground engaging tools engage the ground at substantially equally spaced furrows, and when the hitch tongue is in the neutral position, the hitch tongue is in the desired operating orientation with respect to the frame and extends forward substantially parallel to the operating travel direction and aligned with the frame axis. 
     
     
         4 . The apparatus of  claim 1  wherein the wheel control mechanism comprises a control arm connected between the hitch tongue and the at least one front flotation wheel. 
     
     
         5 . The apparatus of  claim 1  wherein the wheel control mechanism comprises a first hydraulic cylinder connected between the hitch tongue and the frame and a second hydraulic cylinder connected between the at least one front flotation wheel and the frame, and wherein the first and second hydraulic cylinder are connected such that such that pivotal movement of the hitch tongue about the hitch pivot axis moves hydraulic fluid from the first hydraulic cylinder into the second hydraulic cylinder to pivot the at least one front flotation wheel about the wheel pivot axis. 
     
     
         6 . The apparatus of  claim 1  wherein the frame comprises a hitch section and comprising an axle member mounted at a front end of the hitch section substantially perpendicular to the operating travel direction and in a center of a width of the frame, and comprising right and left flotation front wheels mounted on corresponding right and left ends of the axle member about corresponding right and left substantially vertical wheel pivot axes. 
     
     
         7 . The apparatus of  claim 6  wherein the axle member is substantially aligned with rotational axes of the right and left flotation front wheels when the flotation front wheels are rolling in the operating travel direction. 
     
     
         8 . The apparatus of  claim 6  wherein the wheel control mechanism comprises right and left control arms connecting corresponding right and left flotation front wheels to the hitch tongue forward of the hitch pivot axis, the right and left control arms configured such that when the hitch tongue is in the neutral position the right and left flotation front wheels are oriented to roll in the operating travel direction, and such that pivoting the hitch tongue about the hitch pivot axis causes the right and left flotation front wheels to pivot about the corresponding right and left wheel pivot axes such that front edges of the right and left flotation front wheels move in the same direction as the hitch tongue. 
     
     
         9 . The apparatus of  claim 8  comprising right and left flotation outboard front wheels mounted to the frame about substantially vertical wheel pivot axes, and a control linkage connecting the right and left flotation outboard front wheels to the hitch tongue such that moving the hitch tongue away from the neutral position in a selected direction turns the flotation outboard front wheels in the selected direction. 
     
     
         10 . The apparatus of  claim 9  wherein moving the hitch tongue to a selected maximum degree from the neutral position pivots the right and left flotation front wheels and the right and left flotation outboard front wheels about their respective vertical wheel pivot axes such that rotational axes of the right and left flotation front wheels and the right and left flotation outboard front wheels intersect at a desired turning axis. 
     
     
         11 . The apparatus of  claim 10  wherein the desired turning axis is located outside the frame. 
     
     
         12 . The apparatus of  claim 9  comprising a right pair of control hydraulic cylinders comprising a first hydraulic cylinder connected to the hitch tongue and to the frame, and a second hydraulic cylinder connected to the frame and to the right flotation outboard front wheel, wherein chambers of the first and second hydraulic cylinders are connected such that movement of the hitch tongue away from the neutral position moves hydraulic fluid from the first hydraulic cylinder into the second hydraulic cylinder to turn the right flotation outboard front wheel in the direction moved by the hitch tongue. 
     
     
         13 . The apparatus of  claim 12  wherein the hitch tongue extends rearward of the hitch pivot axis and the first hydraulic cylinder of the right pair of control hydraulic cylinders is connected to the hitch tongue rearward of the hitch pivot axis. 
     
     
         14 . The apparatus of  claim 12  comprising a left pair of control hydraulic cylinders comprising a first hydraulic cylinder connected to the hitch tongue and to the frame, and a second hydraulic cylinder connected to the frame and to the left flotation outboard front wheel, wherein chambers of the first and second hydraulic cylinders are connected such that movement of the hitch tongue away from the neutral position moves hydraulic fluid from the first hydraulic cylinder into the second hydraulic cylinder to turn the left flotation outboard front wheel in the direction moved by the hitch tongue, and wherein the first hydraulic cylinder of the left pair of control hydraulic cylinders is connected to the hitch tongue rearward of the hitch pivot axis. 
     
     
         15 . The apparatus of  claim 1  comprising a pivot restraint mechanism selectively operative to secure the hitch tongue in the neutral position. 
     
     
         16 . The apparatus of  claim 15  wherein the pivot restraint mechanism comprises at least one lock pin movable from a locked position, engaging the hitch tongue and the frame and securing the hitch tongue in the neutral position, to an unlocked position where the at least one lock pin is disengaged from the hitch tongue and the frame, and a control selectively operative to move the lock pin to one of the locked position and the unlocked position. 
     
     
         17 . The apparatus of  claim 15  wherein the pivot restraint mechanism comprises an extendable actuator connected between the frame and hitch tongue. 
     
     
         18 . The apparatus of  claim 17  comprising:
 a right extendable actuator movable from a restraint position, resisting rightward pivotal movement of the hitch tongue away from the neutral position, to a release position where the hitch tongue is free to move rightward away from the neutral position; and 
 a left extendable actuator movable from a restraint position, resisting leftward pivotal movement of the hitch tongue away from the neutral position, to a release position where the hitch tongue is free to move leftward away from the neutral position. 
 
     
     
         19 . The apparatus of  claim 18  wherein the right and left extendable actuators are provided by corresponding right and left extendable bias elements, the extendable bias elements configured to be one of fully extended and fully retracted when in the restraint position with the hitch tongue in the neutral position, the extendable bias elements operative to exert a bias force resisting movement of the hitch tongue away from the neutral position. 
     
     
         20 . The apparatus of  claim 17  wherein:
 at least one extendable actuator is pivotally connected at a first end thereof to a first end of a link member; 
 wherein a second end of the link member is pivotally connected to one of the hitch tongue and the frame; 
 a second end of the at least one extendable actuator is pivotally connected to the other of the hitch tongue and the frame; 
 wherein moving the at least one extendable actuator to the restraint position moves the first end of the link member against the one of the hitch tongue and the frame to which the second end of the link member is connected, and wherein moving the at least one extendable actuator to the release position moves the first end of the link member away from the one of the hitch tongue and the frame to which the second end of the link member is connected. 
 
     
     
         21 . The apparatus of  claim 19  wherein the right and left extendible bias elements are provided by corresponding right and left hydraulic cylinders, and comprising an active hydraulic source connected to the right and left hydraulic cylinders through a hydraulic control, the hydraulic control operative to move the hydraulic cylinders to the restraint position, and operative to move the hydraulic cylinders to the release position. 
     
     
         22 . The apparatus of  claim 21  wherein, when the hydraulic cylinders are in the restraint position, pressurized hydraulic fluid at an active pressure from the active hydraulic source is directed into the hydraulic cylinders to exert the bias force, and the active hydraulic source is operative to allow pressurized hydraulic fluid to pass out of the hydraulic cylinders when a hitch force exerted on the hitch tongue in a direction away from the neutral position exceeds the bias force, such that the hitch tongue moves away from the neutral position against the bias force. 
     
     
         23 . The apparatus of  claim 22  comprising a pressure control operative to adjust the active pressure to adjust the bias force. 
     
     
         24 . The apparatus of  claim 22  wherein:
 each of the right and left hydraulic cylinders is pivotally connected at a first end thereof to a first end of a corresponding link member; 
 a second end of the link member is pivotally connected to one of the hitch tongue and the frame; 
 a second end of each hydraulic cylinder is pivotally connected to the other of the hitch tongue and the frame; 
 wherein moving the hydraulic cylinders to the restraint position by directing pressurized hydraulic fluid into the hydraulic cylinders moves the first ends of the link members against the one of the hitch tongue and the frame to which the second ends of the link members are connected; and 
 wherein moving the hydraulic cylinders to the release position moves the first ends of the link members away from the one of the hitch tongue and the frame to which the second ends of the link members are connected. 
 
     
     
         25 . The apparatus of  claim 24  wherein the hydraulic cylinders are fully extended when in the restraint position and fully retracted when in the release position, and configured such that when the hydraulic cylinders are in the release position and the hitch tongue pivots leftward to a selected maximum degree from the neutral position, the first end of a left link member connected to the left hydraulic cylinder bears against the one of the hitch tongue and the frame to which the second end of the right link member is connected, and prevents movement of the hitch tongue beyond the selected maximum degree. 
     
     
         26 . The apparatus of  claim 17  comprising a pivot control selectively operative to move the pivot restraint mechanism from a restraint mode, where the hitch tongue is secured in the neutral position, to a release mode where the hitch tongue is free to pivot about the hitch pivot axis. 
     
     
         27 . The apparatus of  claim 26  comprising a tool control selectively operative to raise and lower the ground engaging tools with respect to the frame, and wherein the pivot control is operatively connected to the tool control such that when the ground engaging tools are raised, the pivot control moves the pivot restraint mechanism to the release mode, and when the ground engaging tools are lowered, the pivot control moves the pivot restraint mechanism to the restraint mode. 
     
     
         28 . The apparatus of  claim 1  wherein the hitch tongue comprises a rear tongue section pivotally attached to the frame about the substantially vertical hitch pivot axis and a front tongue section pivotally attached to the rear tongue section about a substantially horizontal tongue section axis. 
     
     
         29 . A method of controlling the rolling orientation of at least one front flotation wheel of an agricultural implement, the method comprising:
 supporting a frame on rear wheels and on the at least one front flotation wheel for movement along the ground in an operating travel direction, and mounting a plurality of ground engaging tools on the frame substantially equally on each side of a frame axis extending parallel to the operating travel direction;   pivotally mounting the at least one front flotation wheel to the frame about a substantially vertical wheel pivot axis;   pivotally attaching a hitch tongue at a rear end thereof to a lateral mid-point of a width of the frame about a substantially vertical hitch pivot axis located substantially on the frame axis, and pivotally attaching a front end of the hitch tongue to a tow vehicle drawbar with a substantially vertical drawbar pin;   connecting the at least one front wheel to the hitch tongue with a wheel control mechanism configured such that when the hitch tongue is in a neutral position the at least one front wheel is oriented to roll in the operating travel direction, and such that pivotal movement of the at least one front wheel about the wheel pivot axis follows pivotal movement of the hitch tongue about the hitch pivot axis;   operating the tow vehicle to tow the frame along a field surface with the ground engaging tools penetrating the field surface.   
     
     
         30 . The method of  claim 29  operating the tow vehicle to tow the frame along the field surface in a substantially straight line with the hitch tongue secured in the neutral position about the hitch pivot axis, the neutral position selected to place the hitch tongue in a desired operating orientation with respect to the frame; and
 releasing the hitch tongue from the neutral position and turning the tow vehicle such that the hitch tongue pivots about the hitch pivot axis and moves the wheel control mechanism to pivot the at least one front wheel about the wheel pivot axis and turn the frame in the same direction as the tow vehicle. 
 
     
     
         31 . The method of  claim 30  comprising exerting a bias force on the hitch tongue resisting movement of the hitch tongue away from the neutral position, the bias force selected such that when operating the tow vehicle to tow the frame in a substantially straight line along a field surface with the ground engaging tools penetrating the field surface the hitch tongue is secured in the neutral position, and when the tow vehicle is turned the hitch tongue pivots about the hitch pivot axis against the bias force. 
     
     
         32 . The method of  claim 31  wherein the bias force is exerted by a pivot restraint mechanism when the pivot restraint mechanism is in a restraint mode, and wherein no bias force is exerted on the hitch tongue when the pivot restraint mechanism is in a release mode, and comprising operating the pivot restraint mechanism in the restraint mode when turns are in a first shallow range of turn degree, and operating the pivot restraint mechanism in the release mode when turns are in a second sharp range of turn degree.