Blind Fastener Installation via Segmented Collar and Dynamic Tool Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing blind bolts used in structural steel applications have high dispersion in failure load and are expensive to manufacture, with previous solutions being cumbersome and prone to tool damage during use, especially when undoing the fasteners.
Innovation Solution
A method for installing a threaded fastener from one side of a hole using a bolt with an enlarged head and threaded tail, a washer-like collar, and a tool engagement mechanism that prevents separation of the bolt and tool components, allowing for easy assembly and disassembly while preventing rotational movement of the bolt during nut tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a blind bolt is used to install from one side of a hole, then the fastener can be installed where the other side is inaccessible, but the failure load has high dispersion and manufacturing cost is high
Solution Approach 1:
The fastening system is divided into separate components: a bolt with threaded tail portion, a collar, and a nut. This segmentation allows each component to be optimized independently, improving reliability while maintaining one-sided installation capability. The collar and nut work together to provide consistent clamping force.
Solution Approach 2:
The collar acts as an intermediary component between the bolt and the substrate, providing a stable bearing surface that distributes load and reduces failure load dispersion. The tool engagement portion also serves as an intermediary, allowing controlled installation and removal.
2Ease of operation
If a folded collar is passed through the hole and unfolded to provide a large head, then the fastener head is large enough to not pull back through the hole, but the operation of threading and unthreading the bolt from the tool is tedious and the tool may be damaged
Solution Approach 1:
The tool engagement portion allows the bolt to be dynamically inserted and removed from the tool. The moveable member mechanism enables the bolt to be held securely during installation but easily released afterward, reducing operational complexity and tool damage risk.
Solution Approach 2:
The collar is pre-formed with a folded configuration that allows it to be passed through the hole in a compact state and then unfolded to provide the necessary head size. This preliminary folding action simplifies the installation process while maintaining head retention capability.
3Ease of operation
If a larger diameter collar portion is passed through the hole, then the fastener head is larger, but the tool and collar may be damaged during careless use
Solution Approach 1:
The moveable member mechanism allows the tool engagement portion to dynamically adjust during installation. The bolt is securely held during the critical passage through the hole, but can be easily released afterward, reducing the risk of tool and collar damage from careless use while allowing larger collar diameters.
Data Source
AI summary
A method of installing a threaded fastener from one side of a hole through a substrate. The fastener includes a collar and a bolt having a head, a threaded tail portion and a tool engagement portion extending from the tail. The method includes: (a) engaging the tool engagement portion with a bolt engagement portion of a tool (b) passing the bolt through to the far side of the hole and supporting it there by way of the tool, (c) passing the collar through the hole while supporting it with the tool; (d) assembling the bolt and collar to form the threaded fastener having a head larger than the hole; (e) engaging a nut to tighten the fastener; and (f) detaching the tool from the fastener. Separation of the bolt engagement portion and the tool engagement portion is prevented by a moveable member, which engages both portions.