Expandable Threaded Dowel for Reversible Wall Block Joints

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Solution Overview

Problem

Existing construction methods for walls using bricks or wooden dowels are time-consuming, expensive, and difficult for unskilled individuals to align and deconstruct, often requiring glue or clamps, which complicates reuse and recycling.

Innovation Solution

A dowel system with a cylindrical first portion, a conical third portion, and external screw threads for radial expansion and rotational extraction, allowing for easy assembly and disassembly without the need for glue or clamps, using a kit with blocks and an extraction tool for efficient construction and deconstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional brick and mortar construction is used, then structural strength is improved, but construction time and cost increase significantly

Engineering Contradiction:
Improvestructural strengthVSAvoidconstruction time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The wall structure is segmented into discrete modular blocks that can be pre-manufactured and then quickly assembled using dowels, eliminating the time-consuming process of laying individual bricks and applying mortar while maintaining structural integrity through the modular design

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If wooden dowels with nails are used, then construction ease is improved, but structural strength decreases

Engineering Contradiction:
Improveconstruction easeVSAvoidstructural strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The traditional nail-based mechanical connection is replaced with a dowel system that uses radial expansion mechanics - the dowel is inserted in a relaxed state and then expanded radially within the block to create a strong friction-based anchor, providing both ease of construction and high structural strength

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If permanent joints with glue and clamps are used, then structural strength is improved, but ease of deconstruction worsens

Engineering Contradiction:
Improvejoint strengthVSAvoidease of deconstruction
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The joint transitions from a static permanent connection (glue/clamp) to a dynamic reversible connection - the dowel can be inserted to create a strong joint and then easily extracted when deconstruction is needed, allowing the same blocks to be reused for different structures without leaving residual materials

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If complex alignment systems are used, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The block design incorporates built-in alignment features such as recesses and protrusions that create self-aligning interfaces, allowing blocks to be positioned correctly through simple gravity-assisted placement without requiring complex external alignment tools or procedures

Inventive Principle:
Principle #12Equipotentiality

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

Enables quick, cost-effective, and user-friendly construction and deconstruction of walls, improving alignment and structural strength while allowing for easy reuse and recycling of components.

Implementation Method 1

a generally cylindrical first portion (22) having a first internal hole (40) along it, the first portion configured for radial expansion when a radial force is applied within the first internal hole

Methodology Applied
Scientific EffectRadial expansion: Elasticity

Implementation Method 2

the external surface features of at least the second portion comprise an external first screw thread (50-1) configured to provide rotational movement relative to a hole into which the second portion is capable of being received, to enable extraction of the second portion from the hole

Methodology Applied
Scientific EffectScrew thread mechanism: Screw

Implementation Method 3

at least the second portion, and preferably the first and second portions, having external surface features configured to resist translational movement relative to a hole in which the respective portion is capable of being received

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3655668B1Improved dowel
Publication Date: 2021.12.08 MUNRO SAWMILLS LTD
  • EP3655668B1 patent drawingFigure 1a~2
  • EP3655668B1 patent drawingFigure 3a~3c
  • EP3655668B1 patent drawingFigure 4a~4e

AI summary

The present invention relates to a dowel, for example a dowel for a construction kit suitable for constructing a structure such as a wall, a construction kit, an extraction tool, a method of constructing and de-constructing a wall. In particular the invention relates to a dowel for joining blocks, the blocks having at least one hole, comprising: at a first end,a generally cylindrical first portion having a first internal hole along it, the first portion configured for radial expansion when a radial force is applied within the first internal hole;at a second end, a generally cylindrical second portion configured for snug/hammer fit reception into a hole in which the second portion is capable of being received; depending from the second portion, a generally cylindrical third portion, configured for reception into the first internal hole of a further dowel to provide a radial force capable of expanding the first portion; a radial projection between the first and second portions configured to limit insertion of the second portion into a hole in which the second portion is capable of being received;at least the first and second portions having raised external surface features configured to resist translational movement relative to a hole in which the respective portion is capable of being received to resist extraction of that respective portion;and further wherein, the external surface features of at least the second portion comprise an external screw thread configured to provide rotational movement relative to a hole into which the second portion is capable of being received, to enable extraction of the second portion from the hole (when a rotational force is applied tothe dowel relative to the hole).