Adhesive-Fixed Metal Joint Structure for Precise Timber Positioning
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Solution Overview
Problem
Glued-in rods (GIRs) used in timber buildings experience positioning inaccuracies due to gaps between the rod and the hole, leading to potential displacement and reduced joining accuracy between structural members.
Innovation Solution
A metal joint design featuring a small diameter portion with an elongated shape and two large diameter portions spaced along its length, where the small diameter portion has an external thread and irregularities to enhance adhesive bonding, and the large diameter portions are fixed to provide accurate positioning within the hole of a building component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a glued-in rod is fitted into a hole with a gap to be filled with adhesive, then the adhesive can bond the rod to the building component, but the gap causes displacement between the rod and the hole, deteriorating positioning accuracy
Solution Approach 1:
The metal joint is divided into three segments: a small diameter portion that fits into the hole, and two large diameter portions that act as positioning elements. This segmentation allows the positioning function to be separated from the bonding function, resolving the contradiction between needing a gap for adhesive and maintaining positioning accuracy.
Solution Approach 2:
The two large diameter portions act as intermediary positioning elements between the small diameter portion and the hole. These intermediaries maintain accurate positioning while allowing the small diameter portion to have a gap for adhesive bonding, thus resolving the contradiction.
2Ease of manufacture
If the outer diameter of the rod is made smaller than the inner diameter of the hole to allow adhesive insertion, then adhesive bonding is enabled, but positioning accuracy deteriorates due to the gap
Solution Approach 1:
The metal joint is segmented into a small diameter portion for adhesive bonding and two large diameter portions for positioning. This allows the bonding function and positioning function to be performed by different segments, enabling both easy adhesive insertion and accurate positioning.
Solution Approach 2:
Different portions of the metal joint have different diameters to perform different functions locally. The small diameter portion provides gap for adhesive insertion, while the large diameter portions provide accurate positioning, thus resolving the contradiction between ease of manufacture and positioning accuracy.
3Strength
If irregularities are formed on the outer peripheral surface of the small diameter portion, then adhesive bonding strength is enhanced, but the complexity of the joint increases
Solution Approach 1:
Irregularities are formed only on the outer peripheral surface of the small diameter portion where adhesive bonding is needed, rather than throughout the entire joint. This localized modification enhances bonding strength while minimizing the increase in overall joint complexity.
Solution Approach 2:
The surface parameters of the small diameter portion are changed by forming irregularities, which enhances adhesive bonding strength. This parameter change is localized and simple, thus resolving the contradiction between bonding strength and joint complexity.
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 design improves the positioning accuracy of the metal joint within the building component's hole, minimizing gaps and enhancing the bonding strength, thereby improving the overall joining accuracy and quality of structural connections.
Implementation Method 1
fixed to the hole with an adhesive
Implementation Method 2
irregularities are formed on an outer peripheral surface of the small diameter portion in a section between the two large diameter portions
Data Source
AI summary
A metal joint adapted to be fitted into a hole formed in a building component and fixed to the hole with an adhesive includes: a small diameter portion having an elongated shape and an outer diameter smaller than an inner diameter of the hole; and two large diameter portions fixed to the small diameter portion individually at two locations spaced apart from each other in a longitudinal direction of the small diameter portion, each large diameter portion having an outer diameter corresponding to the inner diameter of the hole. Furthermore, irregularities are formed on an outer peripheral surface of the small diameter portion in a section between the two large diameter portions.