Glued-In-Rod Void Sealing With Expanding Foam

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Solution Overview

Problem

In Glued-In-Rod (GIR) systems, glue leaks into voids in wood, preventing a secure bond between the wood and the rod due to the lack of adequate glue at the interface.

Innovation Solution

The method involves drilling an intermediate hole that communicates with voids, injecting expanding foam or a viscous fluid to fill and seal these voids, and then drilling a final hole to ensure the glue adheres only to fresh wood fibers, preventing leakage and enhancing the bond strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If glue is injected into the drilled hole to hold the rod in, then the rod is secured in the wood, but the glue leaks into voids in the wood preventing a secure bond at the interface

Engineering Contradiction:

Improvebond strengthVSAvoidglue leakage

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by injecting expanding foam into the drilled hole before inserting the rod and adhesive. The foam expands to fill voids in the wood ahead of time, creating a barrier that prevents subsequent adhesive leakage. This pre-preparation of the hole ensures that when the rod and adhesive are inserted, the adhesive remains at the critical interface between the rod and wood rather than leaking into voids, thereby resolving the contradiction between securing the rod and preventing glue loss.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If expanding foam is injected into the drilled hole to fill voids, then glue leakage is prevented and bond strength is improved, but the process complexity increases

Engineering Contradiction:

Improvebond strengthVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the hole-filling process into distinct stages: first injecting expanding foam to fill voids, then inserting the rod, and finally adding adhesive. This segmentation allows each material to perform its specific function without interfering with the others. The foam handles void filling, the rod provides structural connection, and the adhesive creates the bond. This segmented approach manages process complexity by making each step straightforward and purpose-driven, rather than attempting to achieve all functions simultaneously with a single complex system.

Inventive Principle:

Principle #1Segmentation

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 effectively seals voids, ensuring a stronger bond between the wood and the rod by maintaining glue at the interface, thereby improving the structural integrity of GIR systems.

Implementation Method 1

injecting expanding foam or a viscous fluid to fill and seal these voids

Methodology Applied

Scientific EffectExpanding foam: Foam

Implementation Method 2

injecting expanding foam or a viscous fluid to fill and seal these voids

Methodology Applied

Scientific EffectViscous fluid:

Data Source

PatentUS20220314485A1System for filling voids in glued-in-rod structures

Publication Date: 2022.10.06 SIMPSON STRONG TIE

AI summary

A glued-in-rod wooden structure includes a prepared hole for sealing voids which may be open to the prepared hole. In one example, the prepared hole is filled with an expanding foam which at least partially fills and seals the voids open to the prepared hole. Thereafter, the prepared hole may be enlarged by drilling to its final diameter for receiving the rod. Any voids in the enlarged hole remain sealed by the expanding foam.