Vehicle Leveling System

An auto-leveling system for a vehicle, the vehicle having a rectangular frame comprising:

• at least three jacks, with one jack on each corner of at least one end of the frame, each jack including a cylinder with a piston with a piston rod connected to a ground-engaging plate, the piston driven by fluid under pressure in an extension pressure line connected to the cylinder to extend the piston rod from the cylinder, and driven by fluid under pressure in a retraction pressure line to retract the piston rod into the cylinder;
• a valve assembly connecting the extension pressure line and the retraction pressure line for each of the at least three jacks to a source of fluid under pressure and to a tank for receiving fluid from the extension pressure line and the retraction pressure line that is not under pressure, the valve assembly including;
• a first directional valve movable to a first position in which the extension pressure line for all of the jacks is in fluid communication with the source of fluid under pressure and the retraction pressure line for all of the jacks is in direct fluid communication with the tank, and movable to a second position in which the extension pressure line for all of the jacks is in direct fluid communication with the tank and the retraction pressure line for all of the jacks is in direct fluid communication with the source of fluid under pressure;
• a directional valve array interposed between the first directional valve and the extension pressure line for all of the jacks, the directional valve array including a directional valve corresponding to each of the at least three jacks, each directional valve movable to a first position in which the valve is closed to prevent fluid flow to the cylinder of the corresponding jack and a second position in which the valve is open to permit fluid flow to the cylinder of the corresponding jack;
• wherein the first directional valve and each directional valve of the directional valve array is moved between the corresponding first and second positions by a solenoid;
• and
• a pressure transducer interposed between the first directional valve and the extension pressure line for all of the at least three jacks;
• and
• a controller including a microprocessor unit (MCU) configured and operable to receive a pressure signal from said pressure transducer and to control the solenoid of the first directional valve and the solenoid of each valve in the directional valve array to measure the pressure individually in each of the at least three jacks.

A method for automatically leveling a vehicle having a rectangular frame and at least three jacks, with one jack mounted at each corner on at least one end of the frame, each jack including a ground-engaging plate that is extended from a cylinder by a piston in the cylinder under fluid pressure on an extension pressure line and that can be retracted into the cylinder by fluid pressure on a retraction pressure line, the method comprising

• (a) measuring the amount of tilt in the pitch and roll directions of the frame;
• (b) determining if the amount of tilt in the roll direction exceeds a predetermined threshold, and if so, then;
• (b)(1) identifying whether the amount of tilt in the roll direction is greater at the front of the vehicle or at the back of the vehicle;
• (b)(2)(i) if the amount of tilt is greater at the front of the vehicle, identifying which jack or jacks (jack(s)) at the front of the vehicle to operate and for how long to reduce the amount of tilt in the roll direction at the front of the vehicle, or
• (b)(2)(ii) if the amount of tilt is greater at the rear of the vehicle, identifying which jack(s) at the rear of the vehicle to operate and for how long to reduce the amount of tilt in the roll direction at the rear of the vehicle, and operating the identified jack(s), and
• repeating steps (a) and (b) until the amount of tilt in the roll direction is within the predetermined threshold;
• (c) then determining if the amount of tilt in the pitch direction exceeds a predetermined threshold, and if so, then
• (c)(1) determining whether to operate the jack(s) at the front or at the back of the vehicle to raise the front or the back of the vehicle to reduce the amount of tilt in the pitch direction and operating the identified jack(s);
• and
• repeating steps (a) and (c) until the amount of tilt in the pitch direction is within the predetermined threshold.

A method for determining the weight of a vehicle having a rectangular frame and at least three jacks, with one jack mounted at each corner of at least one end of the frame, each jack including a ground-engaging plate that is extended from a cylinder by a piston in the cylinder under fluid pressure on an extension pressure line and that can be retracted into the cylinder by fluid pressure on a retraction pressure line, the method comprising:

• operating the jack at each end of the frame until the associated ground-engaging plate is in contact with the ground;
• operating the jack at each end for a predetermined amount of time sufficient to lift the vehicle off the ground;
• measuring the fluid pressure in each jack;
• and
• calculating the weight of the vehicle as the sum of the surface area of the ground-engaging plate for each jack multiplied by the measured fluid pressure for the associated jack.