Tractor Parking Lock Yielding Mechanism for Slope Safety

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing parking lock apparatuses for agricultural tractors are prone to sudden tooth disengagement when loaded, leading to unintended brake release, especially on slopes, due to misalignment of the tooth with the driveline gear, which can result in uncontrolled vehicle movement.

Innovation Solution

Incorporation of a yielding device with helical springs between the braking lever and its hinge, allowing for slight movement to ensure correct alignment and engagement of the tooth with the driveline gear, preventing tooth breakage and maintaining the lock even under load-induced gear turns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the tooth of the working lever is rigidly connected to the braking lever, then the parking lock structure is simple, but the tooth may break due to sudden gear turning when the vehicle is loaded

Engineering Contradiction:

Improveparking lock structureVSAvoidtooth engagement stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies the dynamics principle by introducing a yielding device with helical springs between the braking lever and its hinge point. This allows the braking lever to have slight movement capability, transforming the rigid connection into a dynamic one that can adapt to load-induced gear turns while maintaining reliable tooth engagement

Inventive Principle:

Principle #15Dynamics

2Reliability

If the tooth is allowed to move freely to prevent breakage, then the reliability improves, but the device complexity increases due to additional yielding mechanisms

Engineering Contradiction:

Improvetooth engagement stabilityVSAvoidparking lock structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the connection characteristics between the braking lever and the frame through the yielding device. The helical springs provide a controlled degree of freedom with specific stiffness parameters, allowing just enough movement to prevent tooth breakage while maintaining sufficient stability for reliable parking lock function

Inventive Principle:

Principle #35Parameter changes

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

Enhances the steadiness and security of the parking lock by allowing the tooth to yield and re-align correctly, preventing accidental disengagement and ensuring the vehicle remains locked despite slight driveline gear movements, thus preventing uncontrolled vehicle movement on slopes.

Implementation Method 1

a yielding device (40) comprising two helical springs (42, 43)

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP2184198B1Apparatus for the parking lock of a vehicle, in particular, of an agricultural tractor

Publication Date: 2012.10.31 CNH ITALA

Figure 1
Figure 2
Figure 3~5

AI summary

An apparatus (10) for the parking lock of a vehicle, in particular, of an agricultural tractor. The apparatus (10) comprises a parking lever (13) mechanically linked to a braking lever (14) by means of a cinematic chain (CC). The braking lever (14) comprises a tooth (30) apt to engage at least a braking element (11, 31) of the vehicle. The braking lever (14) is provided with a yielding device (40) placed in correspondence to its own hinge (HG6). The yielding device (40) is able to ease the engagement of the tooth (30) with a gap (31) comprised between two teeth (32, 33) of a driveline gear (11) in order to guarantee a reliable parking lock of the vehicle.