Device for controlling the attitude of an implement drawn by an agricultural machine

A device for controlling the attitude of an implement drawn by an agricultural machine which includes a chassis, two mechanical connecting links disposed between a rear part of the chassis and the implement, means for raising or lowering the implement, and a central processing unit for controlling the raising or lowering means, said attitude controlling device comprising:

• a) two hollow pins, each said hollow pin having a central portion disposed through a respective hole on a respective side of the rear part of the chassis and having a longitudinal axis orthogonal to a force of traction transmitted from the implement by said connecting links;
• b) two mechanical couplings each disposed between a respective said connecting link and a first lateral portion of a respective said hollow pin and, said first lateral portion of each said hollow pin flexing with respect to said central portion in accordance with the force of traction;
• c) two horizontal bars, each said horizontal bar being housed coaxially within a respective said hollow pin and including a first intermediate portion with a horizontal flat face on one side and a reinforcing rib on the opposite side, and a second intermediate portion of a different thickness housed within said first lateral portion of the respective said hollow pin, said rib contacting the internal surface of said central portion of the respective said hollow pin;
• and
• d) four resistive elements deposited in a coplanar manner only on said horizontal flat face of each said bar and symmetrically arranged about a neutral axis defined by the longitudinal axis of said bars, wherein:
• e) said resistive elements are made of a material of the thick film type, have electrical resistance values proportional to deformation caused by the force of traction transmitted from the implement and are connected in a Wheatstone bridge circuit arrangement in such a way that an electrical signal is generated, which can be sent to the central processing unit, proportional to the resistive imbalance of said bridge caused by the deformation.

A device for controlling the attitude of an implement drawn by an agricultural machine which includes a chassis, two mechanical connecting links disposed between a rear part of the chassis and the implement, means for raising or lowering the implement, and a central processing unit for controlling the raising or lowering means, said attitude controlling device comprising:

• a) a first plate being attached to each side of the rear part of the chassis;
• b) two hollow pins, each said hollow pin having a central portion disposed through a respective hole on a respective side of the rear part of the chassis and having a longitudinal axis orthogonal to a force of traction transmitted from the implement by said connecting links;
• c) two mechanical couplings each disposed between a respective said connecting link and a first lateral portion of a respective said hollow pin and, said first lateral portion of each said hollow pin flexing with respect to said central portion in accordance with the force of traction;
• d) each said hollow pin including a cylindrical sleeve and a second lateral portion housed within said cylindrical sleeve;
• said hollow pin and said sleeve being fixed together by means of a first peg which engages a diametrical hole formed at the free end of said second lateral portion of said hollow pin and a diametrical hole formed in said sleeve;
• e) two horizontal bars, each said horizontal bar being housed coaxially within a respective said hollow pin and including a first intermediate portion with a horizontal flat face on one side and a reinforcing rib on the opposite side, and a second intermediate portion of a different thickness housed within said first lateral portion of the respective said hollow pin, said rib contacting the internal surface of said central portion of the respective said hollow pin;
• and
• f) four resistive elements deposited in a coplanar manner only on said horizontal flat face of each said bar and symmetrically arranged about a neutral axis defined by the longitudinal axis of said bars, wherein:
• g) said resistive elements are made of a material of the thick film type, have electrical resistance values proportional to deformation caused by the force of traction transmitted from the implement and are connected in a Wheatstone bridge circuit arrangement in such a way that an electrical signal is generated, which can be sent to the central processing unit, proportional to the resistive imbalance of said bridge caused by the deformation.

A device for controlling the attitude of an implement drawn by an agricultural machine which includes a chassis, two mechanical connecting links disposed between a rear part of the chassis and the implement, means for raising or lowering the implement, and a central processing unit for controlling the raising or lowering means, said attitude controlling device comprising:

• a) two hollow pins, each said hollow pin having a central portion disposed through a respective hole on a respective side of the rear part of the chassis and having a longitudinal axis orthogonal to a force of traction transmitted from the implement by said connecting links;
• b) two mechanical couplings each disposed between a respective said connecting link and a first lateral portion of a respective said hollow pin and, said first lateral portion of each said hollow pin flexing with respect to said central portion in accordance with the force of traction;
• c) two horizontal bars, each said horizontal bar being housed coaxially within a respective said hollow pin and including a first intermediate portion with a horizontal flat face on one side and a reinforcing rib on the opposite side, and a second intermediate portion of a different thickness housed within said first lateral portion of the respective said hollow pin, said rib contacting the internal surface of said central portion of the respective said hollow pin;
• d) said horizontal flat face being disposed in a horizontal plane substantially orthogonal to the force of traction;
• e) resistive elements deposited in a coplanar manner only on said one side having said horizontal flat face of each said bar and symmetrically arranged about a neutral axis defined by the longitudinal axis of said bars, wherein:
• f) said resistive elements have electrical resistance values proportional to deformation caused by the force of traction transmitted from the implement and are connected in such a way that an electrical signal is generated, which can be sent to the central processing unit, proportional to the resistive imbalance.