Draft control system with independent range and sensitivity adjusting means

Claim 1

A DRAFT CONTROL SYSTEM FOR A TRACTOR WITH A HYDRAULICALLY OPERATED LIFT ARM UNDER CONTROL OF A VALVE HAVING SUPPLY, DISCHARGE AND NEUTRAL POSITIONS, COMPRISING, IN COMBINATION, A DRAFT CONTROL MEMBER MOUNTED ON SAID TRACTOR, SAID MEMBER BEING PROPORTIONATELY MOVABLE IN OPPOSITE DIRECTIONS IN RESPONSE TO TENSION AND COMPRESSION DRAFT FORCES EXERTED BY AN IMPLEMENT COUPLED TO SAID TRACTOR, DRAFT FOLLOW-UP MEAN ASSOCIATED WITH SAID MEMBER FOR SHIFTING SAID VALVE BETWEEN SAID POSITIONS IN RESPONSE TO CHANGES IN SAID FORCES, A MANUAL CONTROL LEVER ASSOCIATED WITH SAID FOLLOW-UP MEANS AND POSITIONABLE BETWEEN OPPOSITE LIMITS FOR REGULATING THE AMOUNT OF SAID FORCES REQUIRED TO SHIFT SAID VALVE, AND INDEPENDENTLY ADJUSTABLE MEANS ASSOCIATED WITH SAID FOLLOW-UP MEANS FOR ALTERING THE EFFECTIVE LENGTH OF SAID FOLLOW-UP MEANS BETWEEN SAID MEMBER AND SAID VALVE SO THAT SAID LEVER REGULATES SHIFTING OF SAID VALVE IN RESPONSE TO A DIFFERENT RANGE OF SAID FORCES BETWEEN SAID LIMITS.