Quick Coupler Three-State Locking for Hydraulic Failure Safety

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Solution Overview

Problem

Existing quick couplers for work machines lack the ability to securely lock and unlock tools without requiring subsequent locking or unlocking actions, posing a risk of unintended detachment during hydraulic failures.

Innovation Solution

A quick coupler design featuring two stops on the housing, allowing the locking bridge to be displaced by spring force or hydraulic pressure, enabling three stable states: unlocked, locked, and an additional secure state where the locking bolts are locked but the coupler is still unlocked, ensuring secure tool attachment and preventing unintended detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a quick coupler uses hydraulic drives for tool attachment, then tool change speed and operator convenience are improved, but the risk of unintended detachment due to hydraulic failure increases

Engineering Contradiction:
Improvetool change speedVSAvoidrisk of unintended detachment
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a safety device with a bolt that can be displaced between a locking position and an unlocked position. This bolt acts as a preventive measure against unintended detachment, ready to secure the tool even if hydraulic failure occurs. The safety device provides beforehand protection by establishing a mechanical locking mechanism that can engage independently of the hydraulic system's state.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a quick coupler includes safety devices to prevent unintended detachment, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improveprevention of unintended detachmentVSAvoidnumber of safety components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the safety device with the existing hydraulic quick coupler structure. The bolt of the safety device is integrated into the housing, and its movement is coordinated with the locking bridge and retaining claws. This merging approach allows the safety function to be added without creating a completely separate system, thereby reducing the overall complexity increase that would result from fully independent safety components.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a quick coupler requires subsequent locking actions after tool attachment, then security is improved, but operation time and complexity increase

Engineering Contradiction:
Improvetool securityVSAvoidtime for locking operations
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The safety device is designed to automatically engage the bolt in the locking position when the tool is properly attached to the quick coupler. This preliminary action occurs simultaneously with the tool attachment process, eliminating the need for separate subsequent locking operations. The safety device pre-establishes the secure state through its automatic engagement mechanism.

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 design allows for secure tool attachment and unlocking without subsequent locking, reducing the risk of unintended detachment and enhancing safety by providing an additional stable state that ensures tools remain locked even during hydraulic pressure loss.

Implementation Method 1

A quick coupler design featuring two stops on the housing, allowing the locking bridge to be displaced by spring force or hydraulic pressure

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

allowing the locking bridge to be displaced by spring force or hydraulic pressure

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP4453327B1Quick-change device
Publication Date: 2025.11.26 BÉLA CSERI BESITZUNTERNEHMUNG GBR
  • EP4453327B1 patent drawingFigure 1a~1b
  • EP4453327B1 patent drawingFigure 2a~2b
  • EP4453327B1 patent drawingFigure 3a

AI summary

The invention relates to a quick-change device (1) in which, in order to secure a locating pin of an attachment and to lock a locking component, respectively, securing pins (3.1) and locking pins (2.3), respectively, are pushed in opposite directions out of the housing (6) of the quick-change device (1), wherein as a first stable state of the quick-change device (1) the locking state is set. In addition to a second stable state, an unlocking state, a third stable state can be set for the quick-change device (1).