Compensating hitch

• US 4,239,251 A
• Filed: 07/26/1979
• Issued: 12/16/1980
• Est. Priority Date: 07/26/1979
• Status: Expired due to Term

• Current Assignee: Marvin Landplane
• Original Assignee: Marvin Landplane
• Inventors: Rocksvold, Alvin N.
• Primary Examiner(s): Silverstrim, John P.
• Application Number:
  US06/060,865
• Time in Patent Office: 509 Days
• Field of Search: 280/446 R, 280/446 A, 280/460 R, 280/460 A, 280/461 R, 280/461 A, 280/456 R, 280/456 A, 172/459, 172/450, 172/779, 172/274, 172/272
• US Class Current: 172/274
• CPC Class Codes: A01B 59/043 supported at three points, e.g. by quick-release couplings A01B59/06 takes precedence
• CPC Class Codes: B60D 1/00 Traction couplings; Hitches; Draw-gear; Towing devices devices specially adapted for connection between tractors and agricultural machines or implements A01B59/00; fifth-wheel couplings B62D
• CPC Class Codes: B62D 49/02 modified to take lifting devices
• CPC Class Codes: E02F 3/7663 Graders with the scraper blade mounted under a frame supported by wheels, or the like

Abstract

A compensating hitch adapted to be coupled between a three-point draft system at the rear end of a wheeled tractor and the front end of a trailing earthworking implement which is wheel supported rearwardly of an earthworking blade thereof; the hitch including a link and lever array which functions to maintain the implement and its earthworking blade in a constant pre-set working position when the tractor traverses uneven ground, and which--with a conventional hitch--would cause the trailing implement and its blade to undesirably vary up and down from such constant pre-set working position.

Claims

1. A compensating hitch adapted for coupling between a three-point draft system at the rear end of a tractor and the front end of a trailing earthworking implement in three-point draft relation to the latter;

said compensating hitch comprising an upstanding front frame including a front cross beam and a central post upstanding therefrom, means to connect said front frame with the three-point draft system of the tractor, a rear cross beam in spaced parallel relation to the front cross beam, rigid longitudinal arms on and projecting forward from the ends of the rear cross beam, means transversely pivoting the longitudinal arms at their front ends in connection with the corresponding ends of the front cross beam, a central link upstanding above the rear cross beam, means transversely pivoting the link at its lower end in connection with the rear cross beam, a bellcrank lever disposed rearward of the upper portion of the upstanding central link, the bellcrank lever incuding an upper forwardly projecting leg and a rear depending leg, means transversely pivoting the upper end of the link in connection with the front end of the upper forwardly projecting leg of the bellcrank lever, a separate link extending longitudinally between the bellcrank lever and the post in adjacent but clearance relation to the upstanding central link, means transversely pivoting said separate link at the front end in connection with the post and at the rear end with the lower end of the rear depending leg of the bellcrank lever, and means to connect the ends of the rear cross beam, and the bellcrank lever at its elbow, to the front end of the implement in three-point draft relation.

2. A compensating hitch, as in claim 1, in which said rigid longitudinal arms include portions which project rearward from the ends of the rear cross beam;

and said last named means includes transverse pivots adapted to connect the rear ends of said arm portions and the implement and another transverse pivot adapted to connect the elbow of the bellcrank lever and the implement.

3. A compensating hitch, as in claim 1, in which the post is diagonally braced from the top to the outer ends of the front cross beam whereby the front frame is of generally "A" frame configuration.

4. A compensating hitch, as in claim 1, in which the means to connect the front frame to said three-point draft system of the tractor includes a forwardly opening clevis on each end of the front cross beam, and a forwardly opening clevis on the upper end of the post.

5. A compensating hitch, as in claim 1, in which the means transversely pivoting the longitudinal arms at their front ends with corresponding ends of the front cross beam includes a rearwardly opening, arm-receiving clevis at each end of said front cross beam.

6. A compensating hitch adapted for coupling between a three-point draft system at the rear end of a tractor and the front end of a trailing earthworking implement in three-point draft relation to the latter;

said compensating hitch comprising an upstanding front frame including a front cross beam and a central post upstanding therefrom, means to connect said front frame with the three-point draft system of the tractor, a rear cross beam in spaced parallel relation to the front cross beam, rigid longitudinal arms fixed intermediate their ends on corresponding ends of the rear cross beam, means transversely pivoting the longitudinal arms at their front ends in connection with corresponding ends of the front cross beam, a central link upstanding above the rear cross beam, means transversely pivoting the link at its lower end in connection with the rear cross beam, a bellcrank lever disposed rearward of the upper portion of the upstanding central link, the bellcrank lever including an upper forwardly projecting leg and a rear depending leg, means transversely pivoting the upper end of the link in connection with the front end of the upper forwardly projecting leg of the bellcrank lever, a separate link extending longitudinally between the bellcrank lever and the post in adjacent but clearance relation to the upstanding central link, means transversely pivoting said separate link at the front end in connection with the post and at the rear end with the lower end of the rear depending leg of the bellcrank lever, and means to connect the rear ends of said longitudinal arms, and the bellcrank lever at its elbow, with the front end of the implement in three-point draft relation.

7. A compensating hitch, as in claim 6, for an implement having, at its front end, transversely spaced attachment plates and an upper cross beam spanning between said attachment plates;

and said last named means being transverse pivots, certain of which connect the rear ends of the longitudinal arms with corresponding attachment plates, and another of which pivots connects the elbow of the bellcrank lever with said upper cross beam.

8. A compensating hitch, as in claim 6, wherein the longitudinal arms are fixed substantially centrally of their ends on the corresponding ends of the rear cross beam.