Shaft Part Pre-Assembly Using Flexible Securing Sheet

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Solution Overview

Problem

In mechanical assemblies, particularly in critical applications like automotive and shipbuilding, assembling parts on a shaft can be challenging due to poor lighting, lack of space, difficulty of positioning, and mobility issues, as the type, orientation, and number of parts must be accurately respected during assembly.

Innovation Solution

A pre-assembly of parts is proposed, where all or part of the components intended for a shaft are joined together in a single object using a flexible securing sheet, such as a plastic film or heat-shrink sheath, with markings for orientation, to facilitate handling and assembly by pre-assembling the parts in a workshop or factory.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If parts are assembled on-site in difficult conditions (poor lighting, lack of space, difficulty of positioning), then assembly can be performed in the field, but assembly accuracy and time are compromised

Engineering Contradiction:
Improveassembly ease in difficult conditionsVSAvoidpart alignment and orientation accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-assembling the stack of parts (washers, seals, springs, nuts) in a controlled workshop environment before field deployment. The flexible securing sheet is applied in advance to secure the pre-assembled stack, ensuring proper orientation and alignment are established before the parts are transported to the assembly location. This eliminates the need to perform complex assembly operations in difficult field conditions while maintaining manufacturing precision.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If a rigid securing structure is used to hold the stack of parts, then the parts are securely held, but the structure adds complexity and difficulty in positioning the shaft

Engineering Contradiction:
Improvestack stabilityVSAvoidsecuring structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs a flexible securing sheet (thin film) to hold the stack of parts together. This flexible film wraps around the stack and can be easily positioned on the shaft, eliminating the complexity of rigid securing structures. The flexible nature of the film allows it to conform to the shaft geometry while maintaining stack stability during assembly and operation.

Inventive Principle:
Principle #30Flexible shells and thin films

3Stability of the object's composition

If the flexible securing sheet completely surrounds the stack, then the parts are securely held, but the shaft cannot pass through the stack

Engineering Contradiction:
Improvestack stabilityVSAvoidshaft passage ease
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The flexible securing sheet is segmented with openings that allow the shaft to pass through the stack. The sheet is divided into discrete sections or strips with gaps between them, enabling the shaft to penetrate through the secured stack without removing the securing sheet. This segmentation maintains stack stability while providing clear pathways for shaft installation.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If no marking is provided on the pre-assembly, then the design is simpler, but the axial orientation cannot be verified during assembly

Engineering Contradiction:
Improvemarking system complexityVSAvoidaxial orientation accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent incorporates visual markings (such as colored indicators or marked features) on the flexible securing sheet or on specific parts within the stack to indicate the correct axial orientation. These color-coded or visually distinct markers allow assembly workers to quickly verify proper orientation during installation without adding complex marking systems, thereby maintaining simplicity while ensuring manufacturing precision.

Inventive Principle:
Principle #32Color changes

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

This method simplifies the assembly process by ensuring accurate part alignment and orientation, reducing errors and assembly time, even in difficult conditions, while allowing for easy removal of the securing sheet post-assembly.

Implementation Method 1

the flexible securing sheet comprises an adhesive for adhering to the parts and/or to itself

Methodology Applied
Scientific EffectAdhesive: Adhesive

Implementation Method 2

the flexible securing sheet includes a heat-shrink sheath

Methodology Applied
Scientific EffectHeat-shrink: Thermal Contraction

Data Source

PatentEP3774186B1Pre-assembly of parts
Publication Date: 2022.06.01 GAZTRANSPORT & TECHNIGAZ SA
  • EP3774186B1 patent drawingFigure 1~2
  • EP3774186B1 patent drawingFigure 3~4
  • EP3774186B1 patent drawingFigure 5~6

AI summary

A pre-assembly (1) of parts (2) capable of being mounted on a shaft (4), such as washers, comprising a stack comprising at least two parts (2) arranged in assembly configuration and a flexible securing sheet (3) capable of securing said at least two parts (2) of the stack by totally or partially enclosing all or part of a lateral surface of the stack. A method for manufacturing such a pre-assembly (1).