Chisel plow release mechanisms

• US 4,699,221 A
• Filed: 08/20/1985
• Issued: 10/13/1987
• Est. Priority Date: 01/29/1985
• Status: Expired due to Fees

• Current Assignee: Leon's Manufacturing Co., Inc.
• Original Assignee: Leon's Manufacturing Company Limited
• Inventors: Lange, Kenneth J., Malinowski, Leon A.
• Primary Examiner(s): Johnson, Richard J.
• Application Number:
  US06/767,445
• Time in Patent Office: 784 Days
• Field of Search: 172/705, 172/707, 172/708, 172/710, 172/711, 172/748, 172/755, 172/264-268
• US Class Current: 172/705
• CPC Class Codes: A01B 61/046 the device including an energy accumulator for restoring the tool to its working position

Abstract

This invention relates to an automatic release mechanism for a cultivator which provides good resistance to release of the shank holder and which upon release causes the shank holder to rise to a good height to clear obstacles encountered during operation of the cultivator. The shank holder is mounted so as to pivot about an axis and is retained in the working position by a pair of springs under tension, the forward end of the springs being mounted in front of and beneath the position of the pivot axis of the shank holder, and the moment arm of the springs is such that, as the shank holder pivots, the moment arm decreases resulting in the tangential force applied by the springs to the ground engaging tool about the pivot axis remaining substantially constant during pivoting of the shank holder to clear an obstacle.

Claims

1. A cultivator shank release mechanism comprising:

a mounting plate extending along one side of a frame member of a cultivator;

a pair of back plates extending along a second side of said frame member;

means clamping said mounting plate and back plates to said frame member;

said mounting plate and said back plates extending downward beneath said frame member and converging so that each of said back plates lies adjacent said mounting plate over a lower portion thereof;

a mounting bracket integral with the upper portion of said mounting plate;

shank pivot means mounted on said bracket;

a shank holder pivotally attached to said bracket by said pivot means;

a shank affixed to said shank holder and having an earth working tool located on the lower end thereof;

a pair of springs under tension mounted on opposite sides of said shank holder and each having a front end and a rear end, the rear end of each spring being attached to said shank holder;

spring pivot means fixed to the lower portion of said back plates and mounting plate, the front end of each of said springs being attached at respective pivot points to said spring pivot means, said spring pivot points being located lower than and forwardly of said shank pivot means, the arrangement being such that when, in operation, said ground working tool contacts an obstruction causing said shank and shank holder to pivot upwards, the tangential force exerted on said earth working tool is substantially constant over the full range of pivoting of said shank holder.

2. A cultivator shank release mechanism as claimed in claim 1 wherein said means clamping said mounting plate and said back plates to said frame member comprise first and second bolt means located above and below said frame member respectively.

3. A cultivator shank release mechanism as claimed in claim 2 wherein the lower portion of said frame member and the lower converging portions of said mounting plate and back plates form in side elevation a substantially triangular section.

4. A cultivator shank release mechanism as claimed in claim 1 wherein said spring pivot means comprises a pair of eye bolts, each of said eye bolts extending through and clamping together the lower portions of one of said back plates and said mounting plate, the front end of each of said springs being attached to the eye of the respective eyebolt.

5. A cultivator shank release mechanism attachable to a frame member of an earth cultivator, the frame member having an upper portion, the shank release mechanism comprising:

mounting bracket means;

means fixedly attaching said mounting bracket means to the frame member;

a cultivator shank holder including (a) shank pivot means mounting said cultivator shank holder to said mounting bracket means for pivotal movement of said shank holder in a vertical plane about a pivot axis of said pivot means, (b) a base member having a forward portion which extends forwardly to lie under the frame member, and (c) a rearwardly extending spring retaining means mounted rearwardly of said pivot axis on said base member;

said shank pivot means and said pivot axis being located above said shank holder base member and to the rear of the upper portion of the frame member;

a cultivator shank having an upper portion affixed to said shank holder and an earth working tool affixed to the lower end of said shank;

spring means interconnecting said mounting bracket means and said shank holder and exerting a predetermined force maintaining said earth working tool in a lower position for earth working, said spring means extending when said earth working tool impacts an obstruction to permit said shank holder to pivot upwards about said pivot axis so that said earth working tool rises over the obstruction;

said spring means having a forward end pivotally connected to said mounting bracket means at a pivot point forward of and beneath both said pivot axis of said shank pivot means and said spring retaining means mounted on said base member and a rear end pivotally connected to said spring retaining means of said shank holder base member so that, as said shank holder pivots upwardly, said rear end of said spring means pivots upwardly so that the distance between the axial centerlines of said spring means and the pivot axis of said shank holder decreases and the moment arm of the force exerted by said spring means about said pivot axis decreases whereby the tangential force exerted by said earth working tool remains substantially constant.

6. A release mechanism for an earth working tool as claimed in claim 5 wherein said spring means comprises a pair of coil springs located on either side of said shank holder.