Tractor Coupler Jaw Locking Stability via Guide Surfaces

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Solution Overview

Problem

Existing coupler jaw designs face issues with vibration-induced wear and instability in locking mechanisms, particularly due to short locking surfaces and misaligned opening directions, which can lead to dislocation under minor movements.

Innovation Solution

The coupler jaw design incorporates support surfaces to prevent rotation of the operating lever and limit movement of the catch, directing opening forces effectively through pivot pins, ensuring stable locking and ease of automatic release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the locking surface in the operating lever is kept short, then the device complexity is reduced, but the reliability deteriorates due to dislocation under minor movements

Engineering Contradiction:
Improvestructure simplicityVSAvoidlocking stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces guide surfaces that constrain the operating lever's movement from simple rotation to a controlled path combining rotation and translation. This dimensional constraint prevents dislocation while maintaining a compact locking surface, resolving the contradiction between simplicity and reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The guide surfaces act as an intermediary mechanism between the operating lever and the housing, mediating the lever's movement to ensure it follows a predetermined path. This intermediary structure provides stability without requiring a larger locking surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the catch and operating lever are rigidly connected, then the locking force is improved, but the ease of operation deteriorates due to difficulty in release

Engineering Contradiction:
Improvelocking forceVSAvoidrelease ease
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent creates a dynamic connection between the catch and operating lever through the guide surfaces, allowing the lever to move along a controlled path during operation. This dynamic mechanism maintains strong locking force when engaged while enabling easy release through vertical movement, resolving the contradiction between strength and ease of operation.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the operating lever moves only by rotation, then the device complexity is reduced, but the reliability deteriorates due to vibration-induced wear

Engineering Contradiction:
Improvemovement mechanismVSAvoidwear resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The guide surfaces constrain the operating lever to move along a specific path that combines rotation and vertical translation, rather than pure rotation. This multi-dimensional movement distributes wear across larger surface areas and reduces vibration-induced wear, improving reliability without significantly increasing complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enhances locking stability and ease of operation by maintaining the locking force against opening forces while allowing for efficient automatic unlocking, reducing wear and improving reliability.

Implementation Method 1

A spring is connected to the lower part of the operating lever to pull the catch into the locking position

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The catch and the operating lever are pivoted mutually

Methodology Applied
Scientific EffectRotation: Hinge

Data Source

PatentEP1849632B1Coupler jaw intended for the three-point coupling of a tractor
Publication Date: 2010.04.07 LH ELEVATOR
  • EP1849632B1 patent drawingFigure 1
  • EP1849632B1 patent drawingFigure 2
  • EP1849632B1 patent drawingFigure 3

AI summary

The invention relates to a a coupler jaw for the three-point coupling of a tractor, particularly for a drawbar, the coupler jaw comprising a coupler throat (27), a housing (25), a catch (2), and a spring (8) arranged to pull the catch (2) towards the locking position, as well as an operating lever (3), The catch (2) and the operating lever (3) pivoted to it operate relative to the coupler jaw with the aid of their operating surfaces, which are in the locking position - the locking surface (20) against the ball (11) on the side facing the coupler throat (27), and - the support surface (13) on the upper side of the opening and the sliding top surface (14) of the catch (2), and - the support surface (17) facing the catch (2) in the upper part of the operating lever (3) and the corresponding counter surface (21) of the upper opening, and - the support surface (7) opposite to the catch (2) in the upper part of the operating lever (3) and the corresponding counter surface (33') of the upper opening. The said support surfaces (7, 17) of the catch (2) and the operating lever (3), together with their counter surfaces (33', 21) in the housing, are arranged to create the force locking the catch (2), in order to cancel the opening force (FL) created by the coupler ball (11). Connected to the operating lever (3) are locking surfaces that prevent its rotation and the said support surface (7, 17) opposite to the catch of the operating lever (3) is elongated, thus permitting the operating lever (3) a small degree of opening, thus cancelling the opening force (FL) of the aforesaid coupler ball (11).