Thermoplastic Oil Drain Plug with Elastic Latching

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Solution Overview

Problem

Existing oil drain plugs for motor vehicle engines are expensive and prone to plastic deformation, requiring frequent replacement due to vibrations, which complicates secure sealing and closure.

Innovation Solution

A screw plug with an elastically resilient latching element connected to the screw head, made of thermoplastic material, featuring a retaining element and a movement slot for enhanced mobility and a sealing member, ensuring secure latching and easy opening/closing without loosening due to vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal oil drain plug with a latching nub is used to prevent loosening due to vibrations, then the reliability of the closure is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveclosure securityVSAvoidcomponent complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from metal to thermoplastic and modifies the latching mechanism geometry. The latching element is designed with elastic resilience through material selection and geometric design (thin connection, movement groove), enabling it to deform and engage with the housing's second latching element to prevent loosening under vibration while maintaining simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The latching element is designed as a flexible, elastically resilient component with a thin connection to the screw head. This flexibility allows the latching element to deform during engagement and maintain secure contact with the housing's latching element, preventing the plug from loosening due to vibrations while keeping the structure simple

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a metal screw plug with latching elements is used to ensure secure closure, then the reliability is improved, but plastic deformation occurs leading to frequent replacement

Engineering Contradiction:
Improveclosure securityVSAvoidservice life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameter from metal to thermoplastic, which eliminates plastic deformation issues. The thermoplastic material maintains elastic resilience over repeated use cycles, allowing the screw plug to be opened and closed multiple times without permanent deformation, thereby extending service life while maintaining closure security

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention moves away from the disposable metal plug approach by creating a durable thermoplastic plug that can be reused. The material choice and elastic latching design enable multiple opening/closing cycles without degradation, reducing replacement frequency and cost

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Duration of action of stationary object

If an elastically resilient latching element made of thermoplastic material is used, then the service life and reusability are improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveservice lifeVSAvoidlatching element precision
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent uses thermoplastic material with inherent elastic properties that provide self-compensation for manufacturing tolerances. The material's elasticity allows the latching element to deform and engage properly even with moderate precision, reducing the stringency of manufacturing requirements while ensuring long service life through repeated use

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The latching element is designed with dynamic elastic resilience rather than rigid precision fitting. The element can deform elastically during engagement and operation, accommodating manufacturing variations and enabling reliable latching without requiring extremely tight tolerances, thus extending service life while maintaining manufacturability

Inventive Principle:
Principle #15Dynamics

4Device complexity

If the latching element is connected rigidly to the screw head, then the structural simplicity is improved, but the latching element cannot deflect to ensure secure engagement

Engineering Contradiction:
Improveconnection structureVSAvoidlatching engagement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The latching element is connected to the screw head through a thin, flexible connection that allows elastic deflection. This flexible connection enables the latching element to bend and engage securely with the housing's latching element while maintaining a relatively simple overall structure, resolving the contradiction between structural simplicity and reliable engagement

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The connection between the latching element and screw head is designed to be dynamically flexible rather than rigid. The thin connection allows the latching element to deflect elastically during engagement and operation, ensuring secure latching while keeping the connection structure simple and integrated

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

The solution provides a cost-effective, reusable oil drain plug that securely seals and closes oil drain openings, resisting engine vibrations and simplifying maintenance by allowing multiple uses without deformation, thus reducing replacement costs.

Implementation Method 1

the first latching element is designed in such a way that it is connected to the screw head in an elastically resilient manner

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an ejection bevel is provided on the second latching element. Because of the chamfer, for example, when the screw is opened, the two latching elements move elastically away from one another

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2228520B8Locking screw for openings in motor vehicle engines and housing unit of a motor vehicle engine
Publication Date: 2019.07.24 POLYTEC PLASTICS GERMANY

AI summary

The screw has a screw shaft (10) comprising a thread (12), and a screw head (16) connected with the screw shaft. A latching element i.e. latching nose (34), flexibly connected with the screw head, which cooperates with another latching element arranged at an opening. A movement slot is provided between a retaining element and the screw head, where the retaining element is connected with the screw head at groove and slot-ends. The retaining element circularly surrounds the screw head, where the screw is made of thermoplastic.