Multiple Nut Restrainer Assembly for One-Sided Bolt Installation
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Solution Overview
Problem
The construction industry faces challenges in installing high-strength bolted connections from one side without reducing load-carrying capacity or compromising installation tolerances, due to limitations in existing nut restrainers and bolted connection methods.
Innovation Solution
A multiple fastener restrainer system comprising a mobile portion with cavities to accept nuts and prevent rotation, and a fixed portion that allows lateral movement and attachment to a substrate, enabling the installation of high-strength bolted connections from one side while maintaining load-carrying capacity and tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional high-strength bolted connections are used requiring access from both sides, then load-carrying capacity is maintained, but installation complexity and time increase due to needing access to both sides of the parts being connected
Solution Approach 1:
The patent introduces an intermediary device (the nut restrainer assembly with mobile portion) that mediates between the bolt and the nut. The mobile portion acts as a temporary intermediary structure that holds the nut in position during installation from one side, then is removed after installation. This intermediary device enables one-sided installation without compromising the final connection integrity.
2Ease of operation
If nut restrainers are used to enable one-sided installation, then installation accessibility is improved, but compatibility with standard industry hardware and building codes is compromised
Solution Approach 1:
The patent segments the nut restrainer into two distinct portions: a fixed portion that attaches to the substrate and a mobile portion that holds the nut. This segmentation allows the mobile portion to be removed after installation, leaving only the standard nut and bolt in place. The segmented design enables compatibility with standard industry hardware while providing the one-sided installation capability during the installation process.
Solution Approach 2:
The patent employs preliminary action by pre-attaching the fixed portion to the substrate before inserting the bolt and nut. This preliminary attachment establishes a stable base for the mobile portion to operate from, enabling the subsequent one-sided installation of the bolted connection using standard hardware components.
3Manufacturing precision
If custom floating nuts are used to address tolerance variability, then acceptance of non-concentrical bolts is improved, but compatibility with readily available hardware is severely limited
Solution Approach 1:
The mobile portion of the nut restrainer acts as an intermediary that temporarily accommodates tolerance variability during installation. It holds the nut in the correct position relative to the bolt hole while allowing for non-concentrical bolt insertion. After installation, the mobile portion is removed, and standard nuts and bolts remain in place, maintaining compatibility with readily available hardware.
4Ease of operation
If welding is used to attach nuts to the inaccessible side in advance, then one-sided bolt tightening is enabled, but building code compliance is violated and installation tolerances are reduced
Solution Approach 1:
The patent uses a removable mobile portion as an intermediary device instead of permanently welding the nut to the substrate. This intermediary approach enables one-sided installation while maintaining the ability to remove the restrainer after installation, thereby preserving installation tolerances and maintaining compliance with building codes that prohibit welding of structural components.
5Ease of operation
If blind bolts are used for one-sided installation, then installation accessibility is improved, but load-carrying capacity is reduced and connection types are limited
Solution Approach 1:
The patent employs a removable mobile portion as an intermediary that enables one-sided installation of standard high-strength bolts and nuts. This approach maintains the full load-carrying capacity of traditional high-strength bolted connections, including slip critical connections, unlike blind bolts which have reduced capacity. The intermediary device is removed after installation, leaving a full-strength conventional connection.
Data Source
AI summary
A nut restrainer includes a mobile portion; and a fixed portion. The mobile portion may include at least one cavity configured to accept insertion of a nut and prevent rotation of the nut with respect to the mobile portion.