Blind Fastener Drive Sleeve Structure for Load Transfer and Alignment
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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 rotation of the drive sleeve while allowing vertical translation, and vertical slots for improved alignment and compactness, enabling greater load carrying capacity and adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the collet body legs are used to carry the clamping load, then the fastener can clamp workpieces, but the collet body becomes susceptible to shear stresses and degradation
Solution Approach 1:
The load-carrying function is extracted from the collet body and transferred to the drive sleeve. The drive sleeve is configured to receive the clamping load from the clamping feet and transfer it to the housing, while the collet body is reduced to仅提供 the clamping action without bearing the full load, thereby improving reliability
Solution Approach 2:
The drive sleeve acts as an intermediary component between the collet body and the housing. It receives the clamping force from the collet body legs and transfers it to the housing, protecting the collet body from direct shear stresses while maintaining the clamping function
2Ease 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 and the legs become misaligned with the workpieces
Solution Approach 1:
The drive sleeve serves as a mediator that guides the clamping feet during installation and removal. The slots in the drive sleeve allow the clamping feet to move inward for insertion while the protrusions guide them back to the correct aligned position, maintaining both ease of operation and alignment precision
Solution Approach 2:
The drive sleeve protrusions are pre-positioned to guide the clamping feet into the correct alignment before the clamping action begins. This preliminary alignment action ensures that when the fastener is installed, the clamping feet are already properly positioned relative to the workpieces
3Adaptability or versatility
If the minimum grip length is reduced to increase adaptability, then the fastener can clamp workpieces with greater stack height variance, but the load carrying capacity may be compromised
Solution Approach 1:
The fastener is segmented into distinct functional components: the collet body for clamping action, the drive sleeve for load transfer and alignment, and the housing for structural support. This segmentation allows each component to be optimized independently, enabling reduced grip length while maintaining load capacity through the optimized load path
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 fastener achieves increased load carrying capacity, reduced minimum grip length, and improved alignment, enhancing its applicability and customer appeal by directing load through the drive sleeve and maintaining alignment during clamping and unclamping.
Implementation Method 1
a screw configured to threadingly engage a drive sleeve
Implementation Method 2
the clamping feet are configured to expand radially outward through the sleeve openings
Data Source
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.