Thermoplastic Insert Anchoring with Clamping Against Cracks

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Solution Overview

Problem

Existing methods for joining objects with thermoplastic inserts in fibrous or porous materials, such as wood-based boards, often result in damage due to mechanical loads during the insertion process, especially when the insert has a slightly oversized cross-section and is inserted into narrow openings.

Innovation Solution

A method involving the application of a clamping force perpendicular to the opening axis during the anchoring process to support the object and reduce mechanical loads, allowing for the insertion of an insert portion with an interference fit while minimizing the risk of cracks and bulges, using a machine with clamping elements that apply controlled pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If an insert portion with slightly oversized cross-section is pressed into an opening to create an interference fit, then a strong mechanical connection is achieved, but the second object is subject to considerable mechanical load that may cause cracks or damages

Engineering Contradiction:

Improvemechanical connection strengthVSAvoidcracks and damages to second object

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The clamping force is applied in advance before the interference fit is established, preparing the second object to withstand the upcoming mechanical loads without suffering damage during the insertion process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clamping force acts as a cushioning measure that protects the second object from the harmful effects of the interference fit, distributing and reducing the mechanical stresses that would otherwise cause cracks or damages

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Strength

If the insert portion is pressed into the opening with interference fit, then anchoring strength is improved, but the second object may experience bulging or structural damage

Engineering Contradiction:

Improveanchoring strengthVSAvoidstructural integrity of second object

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The clamping force is applied beforehand to stabilize the second object's structure before the interference fit is imposed, preventing bulging and maintaining structural integrity throughout the anchoring process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clamping force acts as a counteracting force that balances and neutralizes the destabilizing effects of the interference fit, preventing structural damage and bulging of the second object

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Productivity

If mechanical vibration and pressing force are applied simultaneously to anchor the insert, then anchoring efficiency is improved, but the risk of damaging the second object increases

Engineering Contradiction:

Improveanchoring efficiencyVSAvoidmechanical damage to second object

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The clamping force is applied in advance to protect the second object before the high-speed anchoring process begins, allowing efficient vibration-based anchoring without compromising object integrity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The clamping force serves as a protective cushion that enables the use of high-energy vibration and pressing forces during anchoring, while preventing these forces from causing damage to the second object

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 method effectively reduces the risk of damage to the second object by distributing mechanical loads and ensuring a secure interference fit, resulting in a strong positive connection between the objects without causing cracks or visible bulges.

Implementation Method 1

the material having thermoplastic properties is liquefied due to friction heat at least where in contact with the fibrous or porous material

Methodology Applied

Scientific EffectFriction heat: Friction

Implementation Method 2

mechanical vibration, in particular ultrasonic vibration

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 3

it penetrates into the fibrous or porous material of the walls of the opening and forms on re-solidification a positive fit connection

Methodology Applied

Scientific EffectInterpenetration: Permeation

Data Source

PatentUS11472125B2Method of anchoring a first object in a second object

Publication Date: 2022.10.18 WOODWELDING AG

AI summary

A method for joining two objects by anchoring an insert portion provided on a first object in an opening provided on a second object. The anchorage is achieved by liquefaction of a thermoplastic material and interpenetration of the liquefied material and a penetrable material, the two materials being arranged on opposite surfaces of the insert portion and the wall of the opening. During the step of inserting the insert portion in the opening and/or during anchorage a clamping force is applied to opposing surfaces of the second object to prevent the second object from cracking or bulging.