Plastic Pin Fastening Method for Tank Walls

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Solution Overview

Problem

Existing methods for fixing elements, such as flexible membranes or rigid plates, to tank walls with plastic pins often result in undesirable deformation of the pins, leading to unstable attachment due to the rigidity or flexibility of the elements and misalignment issues.

Innovation Solution

A method where the through part of the pin is melted and deformed to form a peg head that wraps freely around the pin, allowing the element to be securely held without stressing the proximal part of the pin, and surface equalization steps are applied to ensure even pressure distribution across the pins.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a heated rivet is pressed against the distal part of the pin to deform it, then the pin can hold the element, but the proximal part of the pin deforms undesirably due to stress transmission

Engineering Contradiction:
Improveholding strengthVSAvoidpin deformation control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The pin is divided into a proximal part (between wall and element) and a distal part (beyond the element). The deformation process is segmented to affect only the distal part through localized heating, preventing stress transmission to the proximal part and avoiding unwanted deformation while maintaining holding strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Heating is applied locally to the distal part of the pin rather than the entire pin. This localized thermal treatment allows the distal part to become deformable for forming the holding head, while the proximal part remains at room temperature and maintains its structural integrity and dimensional stability.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the pin is made flexible to accommodate element positioning, then easier installation is achieved, but the proximal part deforms and tilts under compression

Engineering Contradiction:
Improveinstallation easeVSAvoidpin alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The pin structure is segmented into proximal and distal parts with different functional requirements. The proximal part maintains rigidity for structural support and alignment, while the distal part provides flexibility for element accommodation. This segmentation allows the pin to satisfy both positioning ease and alignment precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different mechanical properties are assigned to different parts of the pin. The proximal part maintains high stiffness and dimensional stability for precise alignment, while the distal part is designed to be more compliant for easy element installation. This local differentiation resolves the contradiction between flexibility and alignment.

Inventive Principle:
Principle #3Local quality

3Strength

If the distal part of the pin is crushed between the element and rivet, then the element is secured, but the element itself deforms undesirably

Engineering Contradiction:
Improveattachment strengthVSAvoidelement shape
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The pin is segmented into proximal and distal parts positioned at different locations relative to the element. The distal part extends beyond the element and is specifically targeted for deformation, while the proximal part remains protected. This spatial segmentation allows selective deformation of the distal part without affecting the element's shape.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distal part of the pin acts as an intermediary between the rivet and the element. It absorbs the deformation and compression forces from the rivet, protecting the element from direct stress. The distal part deforms to form a holding structure that secures the element without transmitting damaging forces to it.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If all pins are deformed simultaneously, then productivity is improved, but misalignment causes undesirable deformation of some pins

Engineering Contradiction:
Improveprocessing speedVSAvoidpin deformation uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

Before deforming all pins simultaneously, a preliminary surface equalization step is performed to ensure all pin distal parts are at the same height and properly aligned. This preliminary action eliminates misalignment issues, allowing subsequent simultaneous deformation of all pins to proceed uniformly without unwanted deformation, thus maintaining both productivity and precision.

Inventive Principle:
Principle #10Preliminary action

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 approach ensures stable fixation of elements on the pins without undesirable deformation, maintaining the element's position at a predetermined distance from the wall, even for flexible materials, by minimizing stress on the pin's proximal part and preventing damage to the pins.

Implementation Method 1

a portion of this through part is melted

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a portion of this through part is melted and the melted portion is pressed

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

the melted portion is pressed so as to form a peg head configured to hold the element on the pin

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3089859B8Method for fastening an element to a pin
Publication Date: 2019.09.18 PLASTIC OMNIUM ADVANCED INNOVATION & RES SA

AI summary

The invention concerns a method for fastening an element (30) to a wall (10) of a tank, said wall (10) having at least one pin (20) made from plastic material. The method comprises the following steps: (a1) Mounting the element (30) on the pin (20) such that a traversing part (23) of the pin (20) passes through the element (30), (a2) Melting at least a portion (235) of the traversing part (23) and pressing on the melted portion (235) such that the melted portion (235) wraps freely around the pin (20) in such a way as to form a pin head configured to hold the element (30) on the pin (20).