Patent ID: 6971453

Claim:
A control system for a three point for coupling an implement to a tractor, the hitch having an upper link and a pair of lower links, first and second double acting hydraulic units, each having a head end chamber and a rod end chamber and each for controlling the position of a corresponding one of the lower links, the control system comprising: a hydraulic supply; a hydraulic tank; a first control valve connected between the supply, the tank and the first hydraulic unit by a first pair of hydraulic lines including a head line connected to the head end chamber and a rod line connected to the rod end chamber, the first control valve independently controlling the first hydraulic unit; a second control valve connected between the supply, the tank and the second hydraulic unit by a second pair of hydraulic lines including a head line connected to the head end chamber and a rod line connected to the rod end chamber, the second control valve independently controlling the second hydraulic unit, the second pair of hydraulic lines being separate from the first pair of hydraulic lines; a third valve connected between the first and second pair of hydraulic lines, the third valve being movable from a first position wherein communication is blocked between the first and second pair of hydraulic lines to a second position wherein the head line of the first pair of hydraulic lines is connected to the head line of the second pair of hydraulic lines and the rod line of the first pair of hydraulic lines is connected to the rod line of the second pair of hydraulic lines.