Replaceable Dyeing Head With Circulation for Uniform Leather Edge Coating

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Solution Overview

Problem

Dyeing the edges of leather products, particularly on large finished products, is difficult due to uneven dye application, inability to adjust dye layer thickness, drying of dye, overedging, and slow color change, especially with low viscosity dyes, using existing stationary machines.

Innovation Solution

A replaceable working head for a dyeing device with a dyeing shaft, a central dye channel, and a circulation system that prevents dye thickening and drying, allowing quick color changes, and includes a thickness adjustment system for uniform dye application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a stationary machine is used for dyeing, then the dyeing process can be performed, but the finished products are large and difficult to hold which hinders quality dyeing

Engineering Contradiction:
Improveease of holding and operating the dyeing deviceVSAvoidquality of dyeing
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The dyeing device is divided into separate functional components: a handheld unit with motor and a separate dye container. This segmentation makes the device easier to hold and operate while maintaining dyeing quality through the structured connection between components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from stationary machines to a handheld portable device, adding the dimension of mobility. The operator can now move the dyeing device to different positions and angles, improving ease of operation on large finished products while maintaining quality through controlled dye application.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the container is placed vertically on the dyeing shaft, then dye can be fed to the shaft, but the dye leaks from the container as a result of gravitational pressure

Engineering Contradiction:
Improveability to feed dye to the shaftVSAvoiddye leaking from the container
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The invention replaces the purely gravitational mechanical feeding system with a pressure-controlled system. A membrane separates the dye in the container from the dyeing shaft, and pressure differences (created by pumping or manual pressure) control the dye flow, eliminating uncontrolled leaking while maintaining reliable dye supply.

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

3Device complexity

If the dye container is stationary and fixed, then the structure is simple, but the dye dries in the container and color changes are slow

Engineering Contradiction:
Improvesimplicity of container structureVSAvoidspeed of color change
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The dye container is made as a separate, detachable component from the dyeing shaft. This allows the container to be quickly removed and replaced with another containing different dye color, enabling fast color changes without complex internal mechanisms, thus maintaining structural simplicity while improving productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a fixed, static dye container to a dynamic, replaceable one. The container can be quickly detached and replaced, introducing temporal dynamics that enable rapid color changes while keeping the overall structure simple and easy to operate.

Inventive Principle:
Principle #15Dynamics

4Device complexity

If a hand device with a fixed distance between the container and dyeing shaft is used, then the structure is simple, but the thickness of the dye layer cannot be adjusted and application is uneven

Engineering Contradiction:
Improvesimplicity of device structureVSAvoiduniformity and thickness control of dye layer
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention introduces an adjustable mechanism that allows the distance between the dye container and dyeing shaft to be dynamically changed. This enables control over dye layer thickness and uniformity while maintaining relatively simple device structure through a straightforward adjustment mechanism.

Inventive Principle:
Principle #15Dynamics

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

Enables high-quality, uniform dye application on all product parts with easy color changes and dye circulation, preventing drying and minimizing losses, suitable for both horizontal and angled dyeing positions.

Implementation Method 1

On the pump section of the shaft, there are, arranged successively and immovably fixed, a first screw pump, an insulating ring dividing the circulation cavity into isolated first and second parts, and a second screw pump

Methodology Applied
Scientific EffectScrew pump mechanism: Archimedes Screw

Data Source

PatentEP4659616A1Replaceable working head of dyeing device for leather products and dyeing device with such working head
Publication Date: 2025.12.10 PL PROJECT LTD
  • EP4659616A1 patent drawingFigure 1~3
  • EP4659616A1 patent drawingFigure 4~7
  • EP4659616A1 patent drawingFigure 8~10

AI summary

The invention relates to a dyeing device for pieces of leather products, which comprises a replaceable working head and a drive unit for transmitting rotary motion to a dyeing shaft (2) provided in the working head, which is connected by a detachable coupling means to said drive unit. The dyeing device also has an adjustment system for adjusting the thickness of the dye layer.