Variable Ratio Lever Mechanism for Agricultural Brake Control

Solution Overview

Problem

Agricultural machines with widely spaced brake discs experience churning losses due to brake discs moving through oil, leading to inefficient brake control, as standard brake levers with constant high ratios require excessive lever movement or high force, making it difficult for drivers to manage brake disc movement effectively.

Innovation Solution

A variable ratio lever mechanism for agricultural vehicles, featuring movement plates with guidance means, such as ball casters, that transition from linear to rotational movement within a guidance track, allowing the force ratio applied to the hand lever to the brake cable to vary from 1 to 7.3, enabling efficient brake disc control by adjusting the lever movement and force distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If brake discs are positioned widely spaced to reduce churning losses, then churning losses are reduced, but the lever movement required to bring brake discs together becomes excessive

Engineering Contradiction:

Improvechurning lossesVSAvoidlever movement distance

Core Design Contradiction:

Loss of energyVSLength of moving object

Solution Approach 1:

The lever ratio is made variable rather than constant. The mechanism transitions from a high lever ratio configuration (when brake discs are apart) to a low lever ratio configuration (when brake discs are close together), allowing the system to adapt its mechanical advantage dynamically during the braking process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The lever ratio parameter is changed during operation. The guidance track geometry causes the lever arms to transition between different effective lengths, thereby changing the force ratio from approximately 7:1 to approximately 1:1 as the brake discs move together.

Inventive Principle:

Principle #35Parameter changes

2Force

If a standard brake lever with constant high lever ratio is used, then force multiplication is achieved, but excessive lever movement is required when brake discs are widely spaced

Engineering Contradiction:

Improveforce multiplicationVSAvoidlever movement range

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The lever ratio is made variable rather than constant. The mechanism transitions from a high lever ratio configuration (when brake discs are apart) to a low lever ratio configuration (when brake discs are close together), allowing the system to adapt its mechanical advantage dynamically during the braking process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The braking process is segmented into two phases: a first phase where the lever provides high mechanical advantage for force multiplication, and a second phase where the lever provides low mechanical advantage for precise control. The guidance track geometry automatically transitions between these phases.

Inventive Principle:

Principle #1Segmentation

3Length of moving object

If the lever ratio is decreased to reduce lever movement, then lever movement distance is reduced, but the force required on the lever becomes too high for a driver's arm

Engineering Contradiction:

Improvelever movement distanceVSAvoidforce required on lever

Core Design Contradiction:

Length of moving objectVSForce

Solution Approach 1:

The lever ratio is made variable rather than constant. The mechanism transitions from a high lever ratio configuration (when brake discs are apart) to a low lever ratio configuration (when brake discs are close together), allowing the system to adapt its mechanical advantage dynamically during the braking process.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The high lever ratio is applied preliminarily when the brake discs are widely spaced, providing the necessary force multiplication to start closing the gap. Once the discs are closer together, the lever ratio automatically decreases, reducing the force requirement for final positioning and control.

Inventive Principle:

Principle #10Preliminary action

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

The variable ratio lever mechanism allows for precise control of brake discs, reducing the effort required for brake engagement and disengagement, enhancing driver control and sensitivity, especially in emergency situations, while minimizing churning losses by optimizing the force transmission to the brake cable.

Implementation Method 1

guidance means for movement within a guidance track... said plate moveable by means of a lever, wherein movement of the lever in one plane results in a first movement of the plate followed by a second movement of the plate

Methodology Applied

Scientific EffectBall caster rotation: Ball Bearing

Implementation Method 2

the ratio of the force applied to the hand lever to the force applied to the brake cable can be varied... allowing the force ratio applied to the hand lever to the brake cable to vary from 1 to 7.3

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP2468591B1Lever mechanism for use on a vehicle

Publication Date: 2015.01.07 AGCO INT GMBH

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AI summary

A lever arrangement for use on an agricultural machine. The lever arrangement comprises a movement plate connectable to an actuation means. The movement plate is provided with guidance means for movement within a guidance track and the plate is moveable by means of a lever. Movement of the lever in one plane results in a first movement of the plate followed by a second movement of the plate. The first movement is a linear, or rotational movement of the plate and the second movement is a rotational, or linear movement of the plate different from the first movement.