Joining Element Anchoring in Thermoplastic Objects

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Solution Overview

Problem

Existing joining elements anchored in objects using thermoplastic materials and mechanical vibration often result in blurred contours at the mouth of openings, especially when anchoring in thin or shallow structures, which is aesthetically undesirable and complicates clear definition of the opening and joining element boundaries.

Innovation Solution

A joining element with a thermoplastic material and mechanical vibration is used, featuring a cylindrical or conical wall anchoring portion with energy directors and a subsequent sealing portion that prevents liquefied material from protruding, ensuring clear contours by using a smooth sealing surface that does not liquefy and fits snugly within the opening, maintaining the original appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the joining element is anchored in the immediate vicinity of the opening mouth using thermoplastic material and mechanical vibration, then anchorage is achieved in thin or shallow structures, but the liquefied material protrudes onto the surface and blurs the contours of the opening and joining element

Engineering Contradiction:
Improveanchorage reliabilityVSAvoidcontour definition
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The joining element is divided into two distinct functional parts: a wall anchoring portion with energy directors for material liquefaction and anchorage, and a sealing portion with a smooth surface that prevents material protrusion. This segmentation allows each part to perform its specific function without interfering with the other, resolving the contradiction between achieving reliable anchorage and maintaining clear contours.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the joining element are given different surface properties: the wall anchoring portion has a rough surface with energy directors that promote material liquefaction and anchorage, while the sealing portion has a smooth surface that prevents material protrusion and maintains clear contours. This local differentiation of properties allows simultaneous achievement of both anchorage reliability and contour definition.

Inventive Principle:
Principle #3Local quality

2Strength

If the circumference of the joining element is pressed against the wall of the opening for anchorage, then anchorage in the walls is achieved, but the liquefied material interpenetrates the surface and protrudes onto the opening surface

Engineering Contradiction:
Improveanchorage strengthVSAvoidcontour clarity
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The joining element is segmented into a wall anchoring portion that performs the anchorage function by pressing against the wall and a sealing portion that performs the containment function by preventing material protrusion. This segmentation allows strong anchorage to be achieved without compromising contour clarity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing portion acts as an intermediary element between the liquefied thermoplastic material and the opening surface. It contains the liquefied material within the opening during the anchorage process, preventing it from protruding onto the surface and thus maintaining clear contours while allowing strong anchorage to occur.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Power

If energy directors are provided on the joining element for effective anchorage, then the thermoplastic material can be liquefied by mechanical vibration, but material protrusion occurs at the opening surface

Engineering Contradiction:
Improvevibration energy transferVSAvoidsurface contour
Core Design Contradiction:
PowerVSShape

Solution Approach 1:

The joining element is segmented into a wall anchoring portion equipped with energy directors for effective vibration energy transfer and material liquefaction, and a sealing portion without energy directors that prevents material protrusion. This segmentation allows powerful anchorage to be achieved without compromising surface contour clarity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Energy directors are localized only to the wall anchoring portion where vibration energy transfer and material liquefaction are needed, while the sealing portion maintains a smooth surface without energy directors. This local differentiation allows effective anchorage power to be concentrated where needed while preventing unwanted material protrusion at the sealing portion.

Inventive Principle:
Principle #3Local quality

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 effectively anchors the joining element in the opening while maintaining clear, defined contours, ensuring a flush and aesthetically pleasing integration, particularly in thin or shallow structures like hollow core boards.

Implementation Method 1

anchoring is effected with the aid of the thermoplastic material and mechanical vibration (e.g. ultrasonic vibration) through which the thermoplastic material is at least locally liquefied

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 2

on re-solidification it forms a positive fit connection with the named surface structures and therewith anchors the joining element in the object

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3120992B1Method for anchoring a joining element in an object and joining element to be used in the method
Publication Date: 2019.02.13 WOODWELDING AG
  • EP3120992B1 patent drawingFigure 1A~1E
  • EP3120992B1 patent drawingFigure 2A~3B
  • EP3120992B1 patent drawingFigure 4~7

AI summary

A joining element to be anchored in an object (10) with the aid of a thermoplastic material and mechanical vibration comprises a wall anchoring portion (3.2) having a circumferential surface which comprises the thermoplastic material and energy directors. The joining element comprises a central tube (2.1) reaching to the distal end, the central tube ending in a distal edge comprising the thermoplastic material. The joining element is anchored in an opening (5) provided in the object (10). For anchoring the joining element in the opening (5), mechanical vibrations e.g. ultrasonic vibrations are coupled into the joining element and the latter is forced into the opening (5). Thereby, the thermoplastic material of the circumferential surface of the wall anchoring portion (3.2) is liquefied and pressed into the opening wall.