THREE POINT HITCH

• US 20090272550A1
• Filed: 04/30/2008
• Published: 11/05/2009
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Blue Leaf IP Incorporated (CNH Industrial N.V.)
• Original Assignee: CNH Industrial America LLC (CNH Industrial N.V.)
• Inventors: Mozingo, Robert E.
• Granted Patent: US 7,784,558 B2
• Time in Patent Office: Days
• US Class Current: 172/1
• CPC Class Codes: A01B 59/066 of the type comprising at least two lower arms and one upper arm generally arranged in a triangle (e.g. three-point hitches)

Abstract

A three point hitch for a work vehicle is provided with one draft link of fixed length and another draft link of variable length. The variable length draft link includes a linear double action hydraulic cylinder assembly, a first attachment plate fixedly connected with one of the arm and the cylinder of the assembly and having a pivot connector configured for pivotal attachment with the vehicle, and a second attachment plate fixedly connected with a remaining one of the arm and the cylinder and having a first pivot connector configured for pivotal attachment with a tilt link and a second pivot connector configured for pivotal attachment with the implement to be supported from the vehicle. The variable length draft link permits lateral adjustment of the angle of the implement with respect to the vehicle center line.

Claims

1. An adjustable draft link for a three point hitch for a work vehicle comprising:

a linear double action hydraulic cylinder assembly including a cylinder and a piston arm extending outwardly from within the cylinder;

a first attachment plate fixedly connected with one of the arm and the cylinder, the first attachment plate including a pivot connector configured for pivotal attachment with a work vehicle; and

a second attachment plate fixedly connected with a remaining one of the arm and the cylinder, the second attachment plate including a first pivot connector configured for pivotal attachment with a tilt link and a second pivot connector configured for pivotal attachment with a load supported from the work vehicle by the link.

2. The adjustable draft link of claim 1 wherein at least the pivot connector of the first attachment plate and the second pivot connector of the second attachment plate are ball joints.

3. The adjustable draft link of claim 2 wherein the first pivot connector of the second attachment plate is either a bushing or a bearing.

4. The adjustable draft link of claim 1 having an adjustment range of between one-half and one foot.

5. The adjustable draft link of claim 1 as a first draft link in combination with a second draft link of fixed length as a set, the second draft link including a first end with a first ball joint pivot connector configured for pivotal attachment with the work vehicle and a second end with a second ball joint pivot connector configured for pivotal attachment with the implement attached with the adjustable draft link.

6. The combination of claim 5 wherein:

the second draft link has a length L between the first and second ball joint pivot connectors; and

the first draft link has the length L between the ball joint pivot connectors at the first and second ends of the first draft link with the hydraulic cylinder assembly in a fully retracted condition.

7. The combination of claim 6 wherein the second draft link includes a first pivot connector at the second end configured for pivotal attachment with a tilt link.

8. The combination of claim 7 wherein the three pivot connectors of the adjustable draft link define a first angle A1 centered at the second pivot connector at the second end and wherein the three pivot connectors of the second draft link define a second angle A2 centered at the second pivot connector at the second end of the second draft link different from the first angle.

9. A three point hitch adapted for adjustably coupling a load with a work vehicle comprising:

an upper link configured for pivotal connection between the vehicle and the load;

a first draft link of adjustable length located below the upper link on a first lateral side of the upper link and having a pivot connector at a first end configured for pivotal connection with the vehicle and a second pivot connector at a second end configured for pivotal connection the load; and

a second draft link of fixed length located below the upper link on a second lateral side of the upper link opposite the first lateral side and having a pivot connector at a first end configured for pivotal connection with the vehicle and a second pivot connector at a second end configured for pivotal connection with the load.

10. The three point hitch of claim 9 wherein the first draft link comprises:

a linear double action hydraulic cylinder assembly including a cylinder and a piston arm extending outwardly from within the cylinder;

a first attachment plate fixedly connected with one of the arm and the cylinder and forming the first end of the first draft link, the first attachment plate including the a pivot connector configured for pivotal attachment with a work vehicle; and

a second attachment plate fixedly connected with a remaining one of the arm and the cylinder and forming the second end of the first draft link, the second attachment plate including the second pivot connector configured for pivotal attachment with the load.

11. The three point hitch of claim 9 wherein each of the first and second draft links has a first pivot connector at the second end configured for pivotal connection with first and second tilt cylinders, respectively extending upwardly from the first and second draft links, respectively, on the first and second lateral sides of the upper link.

12. The three point hitch of claim 11 further comprising:

the pivot connector at the first end of each of the first and second draft links forms an angle with the first pivot connector at the second end of each respective first and second draft link through the second pivot connector at the second end of each respective first and second draft link, the angle of the first draft link pivot connectors being different from the angle of the second draft link pivot connectors.

13. The three point hitch of claim 11 wherein:

the second pivot connector of the first draft link is located at the second end at least essentially along a central longitudinal axis of the first draft link; and

the first pivot connector at the second end of the first draft link is located so as to minimize maximum bending moment on the first draft link at the second end from the first and second pivot connectors.

14. In a three point hitch including an upper link, a first draft link below and to one lateral side of the upper link and a second draft link below and to an another lateral side of the upper link opposite the one lateral side, the improvement wherein the first draft link is of adjustable length and the second draft link is of fixed length.

15. In the three point hitch of claim 14 wherein each of the upper, the first draft and the second draft links includes a first pivot connector at a first longitudinal end configured for pivotal attachment with a work vehicle and a second pivot connector at a second longitudinal end configured for pivotal attachment with a load to be moved by the work vehicle, the improvement wherein the first draft link has a minimum adjustable length between the first and second pivot connectors equal to a fixed length between the first and second pivot connectors of the second draft link.

16. A method of improving the versatility of a three point hitch adapted for adjustably coupling a load with a work vehicle, the three point hitch including an upper link configured for pivotal connection between the vehicle and the load, comprising the steps of:

providing a first draft link of adjustable length below the upper link on a first lateral side of the upper link and having a pivot connector at a first end configured for pivotal connection with the vehicle and a second pivot connector at a second end configured for pivotal connection the load;

while

providing a second draft link of fixed length below the upper link on a second lateral side of the upper link opposite the first lateral side and having a pivot connector at a first end configured for pivotal connection with the vehicle and a second pivot connector at a second end configured for pivotal connection the load.