Draft control linkage for a tractor

Claim 2

In a tractor having draft linkage for connecting the tractor to an implement, hydraulic means including valve means for controlling the vertical position of the draft linkage, draft sensing means for measuring changes in draft loads in the draft linkage, means for operating the valve means in accordance with changes in the draft loads to condition the valve means to raise, hold or lower the implement, operator-set draft input means, a draft control linkage interconnecting the draft sensing means, the operator set draft input means and the valve operating means so that changes in draft forces in the draft linkage from a value set by the operator-set draft input means will condition the valve means to hold or lower the linkage to establish and maintain said set value, the valve operating means including a reciprocable control rod operatively connected to the valve means characterized by said draft control linkage comprising a first member pivotaBle about a first fixed axis by said operator set draft input means, a second member operatively connected to the control rod and pivotally mounted on said first member on a second movable axis spaced from the fixed axis, said draft sensing means operatively connected to the second member to rotate it about the second axis.

Claim 3

In a tractor as set forth in claim 1 further characterized by the first member being a cradle with legs and a third member spaced from said fixed axis, the second member being pivotally mounted on said third member.

Claim 4

In a tractor having draft linkage for connecting the tractor to an implement, hydraulic means including valve means for controlling the vertical position of the draft linkage, draft sensing means for measuring changes in draft loads in the draft linkage, means for operating the valve means in accordance with changes in the draft loads to condition the valve means to raise, hold or lower the implement, operator-set draft input means, a draft control linkage interconnecting the draft sensing means, the operator set draft input means and the valve operating means so that change in draft forces in the draft linkage from a value set by the operator-set draft input means will condition the valve means to hold or lower the linkage to establish and maintain said set value, second operator-set maximum depth position input means, position sensitive means responsive to the vertical position of the draft linkage, the valve operating means including a control rod characterized by a floating lever pivotally connected to the control rod at a first location, the position sensitive means pivotally connected to the lever at a second location and the second operator-set maximum depth means connected to the floating lever at a third location.

Claim 5

In a tractor having draft linkage for connecting the tractor to an implement, hydraulic means including valve means for controlling the vertical position of the draft linkage, draft sensing means for measuring changes in draft loads in the draft linkage, means for operating the valve means in accordance with changes in the draft loads to condition the valve means to raise, hold or lower the implement, operator-set draft input means, a draft control linkage interconnecting the draft sensing means, the operator set draft input means and the valve operating means so that change in draft forces in the draft linkage from a value set by the operator-set draft input means will condition the valve means to hold or lower the linkage to establish and maintain said set value, second operator-set maximum depth position input means, position sensitive means responsive to the vertical position of the draft linkage, the valve operating means including a control rod characterized by a floating lever pivotally connected to the control rod at a first location, the position sensitive means pivotally connected to the lever at a second location and the second operator-set maximum depth means connected to the floating lever at a third location.

Claim 6

In a tractor as set forth in claim 3 further characterized by the second and third locations at opposite ends of the floating lever and the first location is intermediate the ends.

Claim 7

A tractor having draft linkage for connecting the tractor to an implement, hydraulic means including valve means for controlling the vertical position of the draft linkage, draft sensing means for measuring changes in draft loads in the linkage, a housing on the tractor, control means for the hydraulic means within the housing, said housing including side walls and a rear wall, said control means including a control valve mounted on the rear wall, a first lever pivoted on one of the side walls, linkage interconnecting the first lever and the control valve, a control rod connected to the first lever, a control member extending between the side walls and supported on first and second coaxial shafts and secured to rotate with at least one of said shafts extending through said walls, a second lever outside of said housing connected to rotate on said first shaft, a third cross shaft carried by said control member and pivotably mounted thereon on an axis spaced from the axis of said first and second coaxial shafts, third lever means secured to said cross shaft and engaging said control rod through resilient means, first condition sensing means in said housing also secured to said cross shaft to rotate the same on its axis, a fourth floating lever means pivotally carried on a point intermediate its ends on the control rod, a fourth shaft extending through a wall of the housing, a fifth lever on the exterior of said housing secured to the fourth shaft, a sixth lever secured to the fourth shaft inside the housing, linkage connecting said sixth lever to the fourth floating lever at one end thereof, a second condition sensing means within the housing and linkage connecting the second condition sensing means to the other end of the fourth floating lever.

Claim 8

A tractor having draft linkage for connecting the tractor to an implement, hydraulic means including valve means for controlling the vertical position of the draft linkage, draft sensing means for measuring changes in draft loads in the linkage, a housing on the tractor, control means for the hydraulic means within the housing, said housing including side walls and a rear wall, said control means including a control valve mounted on the rear wall, a first lever pivoted on one of the side walls, linkage interconnecting the first lever and the control valve, a control rod connected to the first lever, a control member extending between the side walls and supported on first and second coaxial shafts and secured to rotate with at least one of said shafts extending through said walls, a second lever outside of said housing connected to rotate on said first shaft, a third cross shaft carried by said control member and pivotably mounted thereon on an axis spaced from the axis of said first and second coaxial shafts, third lever means secured to said cross shaft and engaging said control rod through resilient means, first condition sensing means in said housing also secured to said cross shaft to rotate the same on its axis, a fourth floating lever means pivotally carried on a point intermediate its ends on the control rod, a fourth shaft extending through a wall of the housing, a fifth lever on the exterior of said housing secured to the fourth shaft, a sixth lever secured to the fourth shaft inside the housing, linkage connecting said sixth lever to the fourth floating lever at one end thereof, a second condition sensing means within the housing and linkage connecting the second condition sensing means to the other end of the fourth floating lever.