Stabilizer Leg Hydraulic Pressure Detection

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Solution Overview

Problem

Existing stabilizer leg systems for mobile working machines require multiple sensors to accurately determine if a stabilizer leg is in active supporting contact with the ground, leading to increased complexity and risk of sensor damage due to their location near the ground.

Innovation Solution

A stabilizer leg arrangement with a hydraulic cylinder and pressure sensor system that equalizes hydraulic pressures in the first and second chambers when the piston reaches its advanced end position, eliminating the need for additional sensors by using a load-holding valve and directional control valve to determine if the leg is in contact with the ground based on hydraulic pressure thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If differential pressure in the hydraulic cylinder is used to detect ground contact, then detection capability is provided, but additional sensors are required to avoid erroneous detection

Engineering Contradiction:
Improveground contact detection accuracyVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the ground contact detection function with the existing hydraulic cylinder by utilizing the differential pressure already present in the system. The electronic control device processes the differential pressure signal to determine ground contact, eliminating the need for separate detection sensors and reducing system complexity while maintaining detection accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hydraulic cylinder serves dual purposes: it provides the mechanical force for stabilizer leg operation and simultaneously provides the differential pressure signal for ground contact detection. The system uses its own operational parameters (differential pressure) for self-diagnosis and status determination, eliminating the need for external sensing components.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If load sensor is located in or close to foot plate for ground contact detection, then detection capability is provided, but risk of sensor damage increases

Engineering Contradiction:
Improveground contact detection accuracyVSAvoidsensor damage risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses the hydraulic fluid and differential pressure as an intermediary to transmit ground contact information from the foot plate to the electronic control device. Instead of placing a sensor directly at the vulnerable foot plate location, the system transmits the detection signal through the hydraulic medium, allowing remote monitoring and eliminating the need for sensors in high-risk locations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces a mechanical load sensor (which would be physically exposed and vulnerable) with a hydraulic pressure-based detection system. The differential pressure in the hydraulic lines serves as the measurement parameter, substituting a fragile mechanical sensing element with a robust hydraulic signal that can be measured remotely without exposing sensitive components to damage risks.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 solution accurately determines if a stabilizer leg is in active supporting contact with the ground without additional sensors, reducing complexity and minimizing the risk of sensor damage, while ensuring accurate detection of ground contact.

Implementation Method 1

the second chamber is configured to come into fluid communication with the first chamber through at least one flow channel of the hydraulic cylinder when the piston reaches the advanced end position or is on the verge of reaching this end position

Methodology Applied
Scientific EffectHydraulic pressure equalization: Pascal's Law

Data Source

PatentEP3926105B1Stabilizer leg arrangement and mobile working machine comprising such a stabilizer leg arrangement
Publication Date: 2022.11.16 HIAB AB CO CARGOTEC SWEDEN AB
  • EP3926105B1 patent drawingFigure 1
  • EP3926105B1 patent drawingFigure 2~3
  • EP3926105B1 patent drawingFigure 4~6b

AI summary

A stabilizer leg arrangement with a stabilizer leg (25), which is moveable by a hydraulic cylinder (27) into a supporting position in contact with the ground. A piston (32) divides the internal space of the hydraulic cylinder into first and second chambers (34, 35), wherein these chambers are configured to come into fluid communication with each other through a flow channel (41) in the hydraulic cylinder when the piston reaches an advanced end position and abuts against a stop surface. An electronic control device (72) is configured to establish information as to whether or not the stabilizer leg is in the supporting position while taking into account a measuring value (V1) related to the hydraulic pressure in the first chamber (34). The invention also relates to a mobile working machine comprising such a stabilizer leg arrangement.