Post-Installed Anchor Bolt Rotation Expansion Mechanism
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Solution Overview
Problem
Post-installed anchors often have insufficient anchoring strength, leading to slippage under tensile forces, especially in drive-in-type and nut-based fixation systems, which are prone to failure when subjected to larger loads than the initial drive-in force.
Innovation Solution
A post-installed anchor design featuring a bolt body with a threaded end, a fixation member with a threaded end and an expansion end, and a large-diameter member, where the expansion end is widened and extended outward by rotation, providing a strong press fit into the pilot hole for secure fixation, and optionally incorporating a tapered face or multiple expansion pieces for enhanced anchoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drive-in-type fixation sleeve is used to expand the anchor in the pilot hole, then the anchor can be fixed to the concrete floor, but the anchor may slip off under application of a larger tensile force than the drive-in force
Solution Approach 1:
The anchor system transitions from a static drive-in expansion to a dynamic rotation-induced expansion. The fixation member rotates relative to the bolt body, causing the expansion end to progressively widen and extend outward, creating a more reliable press fit that can withstand higher tensile forces without slippage
Solution Approach 2:
The system changes the expansion parameter from linear drive-in force to rotational movement. By rotating the fixation member, the expansion end gradually increases in diameter and extends outward, creating a progressive expansion effect that enhances anchoring strength and prevents slippage under load
2Reliability
If a chemical adhesive is used to fix the anchor in the pilot hole, then the anchor can be securely fixed, but the installation process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces the chemical adhesive system with a purely mechanical expansion system. The fixation member's rotation causes the expansion end to widen and press against the pilot hole walls mechanically, eliminating the need for chemical adhesives and simplifying the installation process while maintaining secure fixation
Solution Approach 2:
The anchor system is self-fixing through its own rotational mechanism. The fixation member's rotation automatically generates the expansion force needed to press the expansion end against the pilot hole walls, eliminating the need for external adhesives or additional fixing materials
3Reliability
If the fixation sleeve is driven in with a drive-in sleeve, then the anchor can be fixed to the pilot hole, but the operation requires specialized tools and more time
Solution Approach 1:
The anchor system eliminates the need for separate drive-in sleeves or specialized driving tools. The fixation member itself, when rotated, generates the necessary expansion force to press the expansion end against the pilot hole walls, making the installation process simpler and more straightforward
Solution Approach 2:
The patent merges the fixation function and the expansion function into a single integrated mechanism. The fixation member's rotation simultaneously achieves both the expansion of the anchor and the pressing against the pilot hole walls, eliminating the need for separate drive-in operations and specialized tools
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 design significantly enhances tensile strength, allowing the anchor to maintain stability under higher loads without significant strength decrease, even when subjected to multiple times the initial force, and simplifies the installation process by eliminating the need for specialized tools or adhesives.
Implementation Method 1
The expansion end of the fixation member riding on the large-diameter member is widened and extended outward, so that the expansion end is press fit in the pilot hole
Data Source
AI summary
The present invention relates to an anchor bolt and more specifically pertains to a post-installed anchor that is securely anchored to, for example, an existing concrete floor. The post-installed anchor has a sleeve fit on a bolt body and a fixation member arranged on an edge of the bolt body and screwed to a threaded end of the bolt body. The fixation member has an internal threaded end and an expansion end. The expansion end is divided into four expansion pieces by slits. The expansion pieces are arranged to face a head of the bolt body and are slightly widened toward the head of the bolt body. One end of the sleeve forms a tapered face. After insertion of the post-installed anchor into a pilot hole (installation hole) bored in the concrete floor, as the bolt body rotates, the fixation member screwed to the bolt body moves toward the sleeve. This movement causes the expansion end of the fixation member to ride on the tapered face of the sleeve and to be pressed open and extended outward. The expansion pieces of the expansion end are then buckled and bite into an inner circumferential face of the installation hole, so that the post-installed anchor is securely fixed to the installation hole.