Blind Fastener Sleeve Structure for Short-Grip Load Transfer
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Solution Overview
Problem
Previous blind fasteners are susceptible to shear stresses, have large minimum grip lengths, and alignment issues due to collet body legs bending inward, limiting their applicability and strength in manufacturing scenarios.
Innovation Solution
A blind fastener design featuring a screw that threads into a drive sleeve with a collet body having clamping feet that mate with sleeve openings, a housing that prevents drive sleeve rotation while allowing axial translation, and vertical slots for improved alignment and compactness, enabling greater load carrying capacity and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the collet body legs are used to carry the clamping load, then the fastener structure is simple, but the collet body is susceptible to shear stresses and degradation
Solution Approach 1:
The load-carrying function is extracted from the collet body legs and transferred to the drive sleeve through the clamping feet. The drive sleeve, with its greater load-bearing capacity, now carries the clamping load while the collet body legs serve primarily for alignment and actuation, resolving the contradiction between structural simplicity and reliability.
2Ease of manufacture
If traditional collet body design is used, then the fastener can be manufactured simply, but the minimum grip length is relatively large
Solution Approach 1:
The load path is redirected through a different dimensional route: instead of loading the collet body legs directly in bending, the load is transferred axially through the clamping feet to the drive sleeve. This dimensional change in the load path enables a shorter grip length while maintaining manufacturing simplicity.
3Ease of operation
If the collet body legs are allowed to bend inward for installation and removal, then the fastener is easy to operate, but alignment issues occur with workpieces
Solution Approach 1:
The clamping feet serve as intermediaries between the collet body legs and the workpieces. They maintain a fixed geometric relationship with the drive sleeve openings, providing stable alignment references that prevent the alignment issues caused by leg bending, while still allowing easy installation and removal.
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 achieves increased load carrying capacity, reduced minimum grip length, and improved alignment, enhancing the fastener's applicability and adaptability in manufacturing, particularly for workpieces with short stack heights.
Implementation Method 1
a screw configured to threadingly engage a drive sleeve
Implementation Method 2
each of the one or more clamping feet mate with a sleeve opening in the drive sleeve
Data Source
Figure 1A~1C
Figure 2A~3B
Figure 3C
AI summary
A fastener including a screw configured to threadingly engage a drive sleeve and method for fastener operation. The fastener, in one example, further includes a collet body with legs that extend from a crown, where each of the legs includes a clamping foot that extends therefrom and wherein each of the clamping feet mate with a sleeve opening in the drive sleeve. The fastener further includes a housing that mates with the drive sleeve such that rotation of the drive sleeve is prevented and vertical translation is permitted.