Nut Restrainer Alignment for One-Sided High-Strength Bolting
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Solution Overview
Problem
Current methods for installing high-strength bolted connections from one side often result in reduced load-carrying capacity, increased costs, and compromised installation tolerances, making them inefficient and costly for construction applications.
Innovation Solution
A nut restrainer system comprising a cup-shaped nut holder with a regular hexagonal profile and centering protrusions that allows for the installation of high-strength bolts from one side, maintaining load-carrying capacity and installation tolerances, and includes a centering tool for precise alignment and affixation to a substrate plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If high-strength bolted connections are installed from one side only, then installation accessibility is improved, but installation tolerances are compromised
Solution Approach 1:
The patent introduces a nut restrainer as an intermediary device that is temporarily installed on the accessible side of the substrate plate. This restrainer holds the nut in precise alignment with the bolt hole, acting as a mediator that enables one-sided installation while maintaining the precision normally achieved through two-sided access. The restrainer includes positioning features that ensure the nut remains coaxial with the bolt hole throughout the tightening process.
Solution Approach 2:
The nut restrainer is installed in advance before the actual bolting operation. By pre-positioning the restrainer with built-in alignment features, the system establishes precise geometric relationships beforehand, allowing the subsequent bolt installation to proceed with maintained tolerances even though access is limited to one side.
2Ease of operation
If blind bolts are used for one-sided installation, then installation accessibility is improved, but load-carrying capacity is reduced
Solution Approach 1:
The patent uses a standard high-strength bolt and nut combination, which is a proven, code-approved fastening system. Rather than inventing a new fastener type, the system copies the geometry and material properties of traditional high-strength bolts, ensuring they meet ASTM specifications. This allows the use of familiar, high-capacity fasteners while achieving one-sided installation through the restrainer mechanism.
3Ease of operation
If welded nuts are used for one-sided installation, then installation accessibility is improved, but installation tolerances are compromised and code compliance is violated
Solution Approach 1:
The nut restrainer serves as a temporary intermediary fixture that enables precise nut positioning without permanent modification to the nut or substrate. Unlike welding which permanently fixes the nut in place with compromised tolerances, the restrainer is a removable tool that holds the nut precisely during installation, then can be removed without affecting the final assembly quality or code compliance.
4Ease of operation
If tapped holes are used for one-sided installation, then installation accessibility is improved, but fabrication time increases and installation tolerances are reduced
Solution Approach 1:
The patent extracts the threading function from the substrate plate itself (which would require time-consuming tapped holes) and relocates it to a separate, pre-threaded nut. This allows the substrate plate to remain as simple drilled holes, while the threading is provided by the removable nut in the restrainer, dramatically reducing fabrication time while maintaining one-sided installation capability.
Data Source
AI summary
In accordance with one or more embodiments of the invention, nut restrainers, centering tools, and methods of use are presented, particularly as applied to high strength bolted connections. Nut restrainers may have an interior profile including a circular profile section and a regular hexagonal profile section, a nut inserted into the nut restrainer may have lateral freedom of movement, and the nut restrainer may have a top plane with one or more centering protrusions. A centering tool for positioning a nut restrainer may have a non-circular head section, a cylindrical positioning section, a threaded section, and a cylindrical restrainer positioning section; a method of positioning a nut restrainer coaxial with a bolt hole using the centering tool.