Asymmetric Roller Sleeve Coupling for Flexographic Printers

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Solution Overview

Problem

Flexographic printing machines face issues with mechanical clearance and misalignment between rollers and sleeves due to cylindrical pin shapes, leading to frequent maintenance, wasted material, and increased printing costs, as well as the need for manual repositioning and test print runs to achieve desired print quality.

Innovation Solution

The introduction of connecting means with a protruding element having inclined side walls and a housing seat with stop walls, providing a larger contact area and preventing mechanical clearance, allowing for quick and precise alignment of sleeves onto rollers, and enabling reliable and durable coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cylindrical pins are used for coupling rollers and sleeves, then the coupling mechanism is simple, but mechanical clearance and misalignment occur leading to frequent maintenance

Engineering Contradiction:
Improvecoupling mechanism simplicityVSAvoidcoupling precision
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by replacing the symmetric cylindrical pin with an asymmetric protruding element that has inclined side walls. This asymmetric shape creates a unique engagement geometry with the housing seat, eliminating the radial clearance inherent in cylindrical pins while maintaining manufacturing simplicity. The inclined walls provide a self-aligning feature that ensures precise coupling between the roller and sleeve.

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If manual repositioning and test print runs are performed to achieve desired print quality, then print precision can be achieved, but production time and material waste increase

Engineering Contradiction:
Improveprint qualityVSAvoidsetup time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by designing the protruding element with inclined side walls that automatically guide the sleeve into correct alignment during the coupling process. This preliminary alignment action eliminates the need for manual repositioning and test print runs, as the precise positioning is achieved automatically during sleeve installation, thereby reducing setup time and material waste.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If cylindrical pins are used for coupling, then the structure is simple, but mechanical clearance leads to increased maintenance needs

Engineering Contradiction:
Improvecoupling structureVSAvoidmaintenance frequency
Core Design Contradiction:
Device complexityVSEase of repair

Solution Approach 1:

The asymmetric protruding element with inclined side walls creates a interference fit with the housing seat, eliminating mechanical clearance without significantly increasing structural complexity. The design maintains simplicity while preventing the wear and misalignment issues that lead to frequent maintenance, thereby reducing maintenance frequency while keeping the coupling structure relatively simple.

Inventive Principle:
Principle #4Asymmetry

4Manufacturing precision

If precise roller positioning is implemented, then print quality improves, but any mechanical clearance nullifies the positioning accuracy

Engineering Contradiction:
Improveroller positioning accuracyVSAvoidpositioning stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The asymmetric protruding element with inclined side walls creates a self-aligning interference fit with the housing seat that eliminates mechanical clearance. This design ensures that the roller positioning accuracy is maintained and not nullified by clearance, as the asymmetric geometry prevents radial movement while the inclined walls provide a self-correcting alignment mechanism.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The inclined side walls of the protruding element create a conical or curved engagement surface that provides a self-aligning effect. This curvature allows the sleeve to be guided into the correct position during installation, ensuring that the roller positioning remains stable and accurate without being affected by mechanical clearance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4098446B1Flexographic printing machine
Publication Date: 2024.03.27 EXPERT SRL
  • EP4098446B1 patent drawingFigure 1
  • EP4098446B1 patent drawingFigure 2
  • EP4098446B1 patent drawingFigure 3~5

AI summary

A flexographic printing machine (1) comprising at least one support structure (2), at least one printing roller (3) pivotably mounted on said support structure (2) and configured to be driven in rotation about a rotation axis (X) and to be intercepted by a tape (N) of material to be printed, said printing roller (3) comprising at least one support core (4) pivotably mounted on said support structure (2); at least one tubular element (5) mechanically connected to said core (4) and extending along said rotation axis (X); connecting means (6) at least partially interposed between said support core (4) and said tubular element (5) and configured to mechanically connect them; said connecting means (6) comprising at least one protruding element (7), extending from said support core (4) radially with respect to said rotation axis (X); at least one housing seat (9) formed on an inner wall of said tubular element (5) and configured to house said protruding element (7) of said support core (4); said protruding element (7) is provided with at least two side walls (8) inclined with respect to said rotation axis (X), and said housing seat (9) is provided with two stop walls (10) inclined with respect to said rotation axis (X) and configured to receive said inclined side walls (8) of said protruding element (7) in bump.