Hydraulic Switch Layout for Tilt-Triggered Flow Cutoff

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Solution Overview

Problem

Hydraulic circuits in machinery such as fork lift trucks and excavators often experience unexpected release of mechanical components due to unstable conditions, leading to safety risks, and rely heavily on operator experience to prevent tipping and load management.

Innovation Solution

A hydraulic switch arrangement with a first fluid switch operated by a second fluid switch, which can be activated by tilting or inertia, ensuring safe operation by preventing hydraulic fluid flow when the apparatus becomes unstable, utilizing a rotatable element with arms and a ball mechanism to change operational configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single fluid switch is used to control hydraulic circuit flow, then the device complexity is low, but the reliability of detecting unstable conditions is insufficient

Engineering Contradiction:
Improvereliability of detecting unstable conditionsVSAvoidcomplexity of switch arrangement
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hydraulic switch arrangement is segmented into two distinct fluid switches: a first fluid switch with a first operational member and a second fluid switch with a second operational member. Each switch independently detects different aspects of unstable conditions (tilting and inertia/shaking), allowing the system to achieve higher reliability through multiple detection mechanisms rather than relying on a single complex switch.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the first fluid switch is positioned in the primary fluid flow path to prevent flow, then the safety is improved, but the pressure required to operate the switch increases

Engineering Contradiction:
Improvesafety of preventing hydraulic fluid flowVSAvoidpressure on first fluid switch
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The second fluid switch acts as an intermediary that detects unstable conditions (tilting or shaking) and triggers the first fluid switch to close. This mediation allows the first fluid switch to operate at lower pressures since it only needs to respond to the signal from the second switch rather than directly detecting high-pressure instability conditions, thereby maintaining safety while reducing operational pressure requirements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a fluid switch is made highly sensitive to detect unstable conditions, then the measurement precision is improved, but the switch may activate falsely under normal operation

Engineering Contradiction:
Improveprecision of detecting tilting or shakingVSAvoidfalse activation under normal operation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system employs feedback through the interaction between the two fluid switches. The second fluid switch detects unstable conditions and provides feedback to the first fluid switch, which then closes to prevent hydraulic fluid flow. This feedback mechanism ensures that activation only occurs when both detection mechanisms confirm unstable conditions, thereby maintaining high measurement precision while preventing false activations during normal operation.

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

The solution provides reliable and accurate prevention of hydraulic fluid flow when the apparatus tilts or becomes unstable, ensuring safe operation and preventing unexpected component release, thus enhancing safety and reducing the risk of accidents.

Implementation Method 1

The second fluid switch can be operated by tilting of the hydraulic switch arrangement for example. The second fluid switch can also be operated through inertia or shaking for example.

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 2

passage of hydraulic fluid through the first hydraulic flow path to the activating element causes release of hydraulic fluid from the chamber and flow of hydraulic fluid through the second flow path

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Gradient

Data Source

PatentEP3105480B1Hydraulic switch
Publication Date: 2021.07.21 EDWARDS VINCENT
  • EP3105480B1 patent drawingFigure 1~2
  • EP3105480B1 patent drawingFigure 3a
  • EP3105480B1 patent drawingFigure 3b~4

AI summary

The present invention relates to a hydraulic switch arrangement and a fluid switch for incorporating into a hydraulic switch arrangement that may be included in a hydraulic circuit for inhibiting flow of hydraulic fluid through a hydraulic circuit in the event of movement of an apparatus or platform from a stable to an unstable condition. Such platforms or apparatus may include for example, cranes, excavators, teletrucks and forklift trucks and roll over incidents of such machinery is common leading to numerous fatalities. Aspects of the present invention ensure fast switching in the event of a transfer from a stable to an unstable condition.