Lifting Machine Axle Suspension Switching for Roll Comfort and Stability

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Solution Overview

Problem

Lifting machines experience uncomfortable rolling movements on uneven terrain, which can be mitigated by shock absorbers but are expensive, and existing solutions do not ensure safety while enhancing comfort.

Innovation Solution

The design incorporates two oscillating axles with the ability to deactivate the suspension of one axle, allowing both axles to pivot freely under specific conditions, controlled by a driver-operable suspension activation/deactivation member and a control unit that uses sensor data to manage suspension activation and deactivation, ensuring optimal comfort without compromising safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If shock absorbers are mounted on the operator's cab to mitigate rolling motion, then driving comfort is improved, but device cost increases significantly

Engineering Contradiction:
Improvedriving comfortVSAvoiddevice cost
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements a dynamic suspension system where the front axle can switch between locked and unlocked states. When unlocked, the axle pivots freely to absorb terrain irregularities, providing comfort without requiring expensive cab-mounted shock absorbers. The system adapts its stiffness dynamically based on operating conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The suspension system changes the effective stiffness parameter of the front axle by controlling the lockable actuator. In the unlocked state, the axle has high compliance for comfort; in the locked state, it has high stiffness for stability. This parameter switching resolves the contradiction between comfort and cost.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If both axles are mounted freely for pivoting to maximize comfort, then driving comfort is improved, but lateral stability deteriorates under certain conditions

Engineering Contradiction:
Improvedriving comfortVSAvoidlateral stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts the front axle's pivoting capability based on real-time sensor feedback. When sensors detect conditions that may compromise stability (such as excessive inclination), the control unit locks the front axle to maintain lateral stability. Otherwise, the axle remains unlocked for comfort.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent incorporates sensors that continuously monitor machine inclination and operating conditions, feeding this information to the control unit. The control unit uses this feedback to determine when to lock or unlock the front axle, creating a closed-loop control system that balances comfort and stability.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the suspension is always activated for free pivoting, then driving comfort is improved, but safety is compromised when lateral instability risk exists

Engineering Contradiction:
Improvedriving comfortVSAvoidmachine safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The suspension system transitions from a static always-activated state to a dynamic state controlled by sensor feedback. The lockable actuator on the front axle allows the system to switch between compliant (unlocked) and rigid (locked) states based on real-time stability assessment, ensuring safety when needed while maintaining comfort when safe.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Sensors monitor machine inclination and operating conditions continuously. When sensor data indicates a risk of lateral instability, the control unit deactivates the suspension by locking the front axle. This feedback mechanism ensures safety by preventing suspension activation under hazardous conditions.

Inventive Principle:
Principle #23Feedback

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 configuration enhances driving comfort by allowing the axles to pivot freely while maintaining safety, preventing lateral instability through controlled suspension deactivation based on inclination and other operational parameters.

Implementation Method 1

The front axle suspension comprises at least one hydraulic actuator disposed between the front axle and the chassis and connecting the front axle to the chassis

Methodology Applied
Scientific EffectHydraulic actuation: Hydraulic Press

Implementation Method 2

one or more shock absorbers

Methodology Applied
Scientific EffectShock absorption: Damping

Data Source

PatentEP3844093B1Lifting machine in particular for handling loads
Publication Date: 2023.11.08 MANITOU BF SA
  • EP3844093B1 patent drawingFigure 1A
  • EP3844093B1 patent drawingFigure 1B
  • EP3844093B1 patent drawingFigure 2

AI summary

The invention relates to a lifting machine (1) comprising a lifting arm (3), a rolling chassis (2) equipped with at least one front axle (5) and one rear axle (6), and a sensor for measuring the tilt of the lifting arm (3) in relation to the chassis (2), the rear axle (6) being pivotably mounted around an axis that is parallel to the longitudinal axis of the machine (1). The rear pivoting axle (6) is mounted to freely pivot inside an angular range defined by two abutments supported by said chassis (2), the front axle (5) is coupled to the chassis (2) by a pivoting connection with an axis that is parallel to the longitudinal axis of the machine (1) and is equipped with an activatable/deactivatable suspension (9) in order to allow the relative pivoting between the front axle (5) and the chassis (2) to be damped, said suspension (9) being deactivated at least when the angle value measured by sensor (4) for measuring the tilt of the lifting arm (3) is greater than a predetermined threshold value.