Cylindrical Gasket Mould with Segmented Insert

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Solution Overview

Problem

Existing methods for producing cylindrical gaskets with annular lips for cylinder and piston mechanisms often result in lips with molding burrs and inaccuracies, requiring additional finishing work to ensure tightness, and the molds used are complex, inconvenient, and expensive to produce.

Innovation Solution

A molding method and mold design where the housing cavities for the lips are created in a single solid body, eliminating the need for cores or modular parts and allowing the lips to be formed without being at the closing surface, thus avoiding burrs and simplifying the mold design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the closing surface of the mould passes through the impressions of the annular lips to avoid undercuts, then the gasket can be extracted from the mould, but the lips are not free from moulding burrs or inaccuracies and require finishing work

Engineering Contradiction:
Improveextraction of gasket from mouldVSAvoidprecision of sealing lips
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The mould is divided into three parts: a fixed part, a movable part, and a removable central insert. The central insert contains the impressions for the annular lips and can be removed independently, allowing the lips to be formed with high precision while facilitating easy gasket extraction without compromising lip accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The central insert acts as an intermediary element between the fixed and movable mould parts. It provides the precise impressions for the sealing lips while being removable to enable gasket extraction, thus mediating between the conflicting requirements of precision and ease of operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If a mould with multiple parts arranged side by side with a removable central part is used, then the lips do not require further finishing work, but the mould turns out to be difficult to make and considerably expensive

Engineering Contradiction:
Improveprecision of sealing lipsVSAvoidcomplexity of mould structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mould is segmented into a fixed part, movable part, and a removable central insert that can be easily fabricated and replaced. This segmentation allows the complex precision requirements to be localized to the insert, which can be made separately and inserted into the simpler fixed and movable mould parts, reducing overall manufacturing difficulty

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The complex central insert containing the lip impressions is extracted as a separate removable component from the main mould structure. This allows the insert to be manufactured independently with high precision using specialized techniques, while the main mould body remains simple and easy to manufacture

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If traditional moulds with cores or modular parts are used to form the annular lips, then the lips can be formed, but additional finishing work is required to remove burrs and correct inaccuracies

Engineering Contradiction:
Improveease of forming lipsVSAvoidprecision of sealing lips
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The central insert is pre-formed with the exact impressions for the annular lips before being installed in the mould. This preliminary action ensures that the lips are formed with the required precision directly during moulding, eliminating the need for subsequent finishing operations to remove burrs or correct inaccuracies

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3825090B1Method and mould for making cylindrical gaskets
Publication Date: 2025.03.26 ELLEGI
  • EP3825090B1 patent drawingFigure 1~2
  • EP3825090B1 patent drawingFigure 3
  • EP3825090B1 patent drawingFigure 4

AI summary

Method for producing at least one substantially cylindrical gasket (16), preferably with a generally annular section, of the type comprising, along the axis of symmetry of the same gasket, a base end (9) and a top end (10) reciprocally joined by an outer, substantially longitudinally extending, side surface (11) and by an inner side surface (12) substantially longitudinally extending too, a first annular lip (13) jutting externally from the outer side surface (11) and a second annular lip (14) jutting internally from the inner side surface (12), the method comprising in sequence the steps of: • preparing a mould (1) with a fixed part (3) and a movable part (2), which can be coupled in abutment along a closing surface (4); • closing the mould (1) by sealingly coupling the fixed part (3) and the movable part (2) of the mould (1) to one another; • moulding a moulding material between the fixed part (3) and the movable part (2) of the mould (1) for making said gasket (16); • opening the mould (1) by separating the respective fixed part (3) from the movable part (2); • removing the moulded gasket (16); and wherein the fixed part (3), or vice versa the movable part (2), of the mould (1) comprises at least one housing cavity (5) of the moulding material and the movable part (2), or vice versa the fixed part (3), of the mould (1) comprises at least one clamping portion (6), preferably flat or convex, complementary to the aforesaid at least one housing cavity (5). Such moulding method advantageously provides that the aforesaid closing surface (4), comprising the aforementioned at least one clamping portion (6), delimits at least the top end (10) of the gasket (16) defined by such at least one housing cavity (5) and that the at least one housing cavity (5) is made in a single solid body.