Quick Coupler Locking Bridge for Fail-Safe Attachment Retention

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Solution Overview

Problem

Existing quick-change devices for construction machinery are prone to unintentional unlocking of locking bolts due to external forces, leading to attachments falling off.

Innovation Solution

A quick-change device with a hydraulically operated bridge and locking bolts, featuring a spring or hydraulic element, stop elements, and a pressure element to ensure mechanical safety by limiting the movement of locking bolts, even under external forces, using a guide element and stop elements to maintain a minimum locking position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If locking bolts are used to secure attachments, then attachment retention is improved, but unintentional unlocking due to external forces occurs

Engineering Contradiction:
Improveattachment retentionVSAvoidunintentional unlocking
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bridge is made movable between a retracted position and an extended position, allowing the locking mechanism to dynamically adapt to external forces. When external forces act on the attachment, the bridge can move from the extended locking position to the retracted position, preventing unintentional unlocking while maintaining secure retention during normal operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bridge acts as an intermediary element between the locking bolts and the attachment. It mediates the interaction by providing a movable connection that allows controlled movement of the locking bolts in response to external forces, thereby preventing direct transmission of harmful forces to the locking mechanism while maintaining secure attachment retention.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If locking bolts are extended to secure attachment, then locking strength is improved, but vulnerability to external forces increases

Engineering Contradiction:
Improvelocking strengthVSAvoidexternal forces
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The locking bolts are integrated with the movable bridge, allowing them to dynamically adjust their extended/retracted state. During normal operation, the bridge extends the locking bolts to provide strong securement. When external forces exceed a certain threshold, the bridge moves to the retracted position, pulling the locking bolts inward to eliminate the vulnerability to external forces.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The movable bridge provides a cushioning mechanism that absorbs external forces before they can directly impact the locking bolts. By allowing controlled movement of the bridge, the system beforehand cushions against potential harmful forces, preventing them from causing unintentional unlocking while maintaining strong locking during normal conditions.

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

3Ease of operation

If hydraulic device is used to operate bridge, then ease of operation is improved, but reliability under hydraulic failure decreases

Engineering Contradiction:
Improvebridge operationVSAvoidlocking reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The movable bridge with locking stops creates a self-service mechanism that automatically responds to external forces without requiring continuous hydraulic pressure. The bridge can move between positions and the locking stops automatically engage to prevent over-retraction, providing a degree of reliability that does not depend entirely on the hydraulic system remaining functional.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking stops on the bridge provide a beforehand cushioning mechanism that ensures minimum locking position even in case of hydraulic failure. The stops are positioned to prevent the bridge from moving beyond a certain point, thereby ensuring that the locking bolts maintain a minimum extended position and continue to provide reliable locking even when the hydraulic device can no longer maintain pressure.

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

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

Ensures secure attachment retention by preventing unintentional unlocking, even with external forces or hydraulic failures, allowing for safe and reliable attachment and detachment of tools without additional valves.

Implementation Method 1

at least one longitudinally extending spring or hydraulic element acting on at least one locking bolt across the bridge

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

movable in the longitudinal direction of the quick-change device by means of a hydraulic device of the quick-change device

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4711525A1Quick change device
Publication Date: 2026.03.18 BÉLA CSERI BESITZUNTERNEHMUNG GBR
  • EP4711525A1 patent drawingFigure 1
  • EP4711525A1 patent drawingFigure 2
  • EP4711525A1 patent drawingFigure 3

AI summary

The invention relates to a quick-change device for coupling an attachment to a working machine, wherein the quick-change device comprises a housing with a receiving claw; at least one locking bolt movable in a longitudinal direction of the quick-change device from an unlocking position to a locking position and back; a bridge extending in a transverse direction and movable by means of a hydraulic device, which holds the at least one locking bolt; and at least one spring or hydraulic element acting on the at least one locking bolt via the bridge.According to the invention, the bridge has at least one guide element movable in the longitudinal direction, wherein the bridge has a recess on at least one side of the guide element, and the quick-change device has at least one stop element oriented parallel or at an acute or obtuse angle to the longitudinal direction, each pivotally suspended and receptable in the at least one recess of the bridge, with a locking stop for the at least one guide element for limiting movement of the bridge in the direction of the receiving claw and a pressure element movable in the longitudinal direction for pushing away the at least one stop element against the spring force of at least one elastic element of the quick-change device acting in the transverse direction.