Quick-Coupling Locking Mechanism for Hydraulic Systems

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Solution Overview

Problem

Quick-couplings in hydraulic systems experience loosening due to high pressures and pulsating frequencies, leading to detachment of threaded connections, which existing methods like gluing fail to adequately prevent.

Innovation Solution

A quick-coupling design featuring a male and female portion with an outer circumferential slot and a radially inclined, hammer-like enlarged portion that undergoes plastic deformation upon assembly, locking the connection securely.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional threaded connections are used in hydraulic systems, then assembly is simple and quick, but the threaded connection loosens progressively due to high operating pressures and hydraulic fluid pulsating frequencies

Engineering Contradiction:
Improvethreaded connection stabilityVSAvoidconnection structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connection structure is segmented into distinct functional elements: the threaded portion for initial engagement, the circumferential slot for positioning, and the hammer-like enlarged portion for locking. This segmentation allows each element to perform its specific function while maintaining overall connection reliability under hydraulic pressure and pulsating frequencies.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The circumferential slot and hammer-like enlarged portion are pre-configured in the female and male portions respectively before assembly. During assembly, the slot guides the enlarged portion into position, and the radially inclined wall automatically positions the enlarged portion to engage with the slot, creating a preliminary alignment that ensures proper locking engagement without requiring additional adjustment steps.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If glue is used to connect threaded parts, then loosening is prevented, but the glueing operations require comparatively long time

Engineering Contradiction:
Improvethreaded connection stabilityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The chemical bonding method (glue) is replaced with a purely mechanical locking system consisting of the circumferential slot and hammer-like enlarged portion. This mechanical interlocking mechanism provides immediate and reliable prevention of loosening without requiring chemical curing time, thereby maintaining high assembly speed and productivity while ensuring connection stability under hydraulic conditions.

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

3Reliability

If a locking mechanism with circumferential slot and hammer-like enlarged portion is implemented, then threaded connection loosening is prevented, but manufacturing complexity increases

Engineering Contradiction:
Improvethreaded connection stabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking function is merged into the existing threaded connection structure by integrating the circumferential slot and hammer-like enlarged portion as inherent features of the male and female portions. Rather than adding separate locking components, the design combines the threading, slot, and locking protrusion into unified structures that can be manufactured as single pieces, thereby preventing loosening without significantly increasing manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The complex locking features (circumferential slot and hammer-like enlarged portion) are implemented only in the specific regions where they are needed for locking engagement, while the rest of the connection structure maintains simple threaded geometry. This localized application of complexity allows the locking function to be achieved without requiring complex manufacturing processes for the entire component.

Inventive Principle:
Principle #3Local quality

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 effectively prevents loosening of threaded connections under high pressure and frequency conditions, ensuring a secure engagement even in extreme hydraulic system environments.

Implementation Method 1

by a force F transmitted by a press, as shown in figure 4 by the arrow (f), the enlarged portion 8, by a plastic deformation of the wall 7, will be brought to a permanent type of contact with the slot 6, thereby locking the portion 2 with respect to the tubular element 4

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP1746326B1A quick-coupling with threadedly engaged portions
Publication Date: 2012.03.14 FASTER SPA
  • EP1746326B1 patent drawingFigure 1
  • EP1746326B1 patent drawingFigure 2
  • EP1746326B1 patent drawingFigure 3

AI summary

A safety device for threadedly engaged portions of a quick-coupling (1) comprises a first quick-coupling portion (2), including a thread (3), and a circumferential slot (6), and a second quick-coupling portion (4), having a respective thread (3) and assembled with the thread (3) of the first portion, said second quick-coupling portion (4) having a circumferential region (7) which, at a free end thereof and at said circumferential slot (6), comprises a hammer-like enlarged portion (8) which can be coupled with the circumferential slot (6) after having fully assembled the quick-coupling portions (2,4).