Breakaway Bushing Presets Securing Member for Metal-on-Metal Fastening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fasteners with preset securing members face issues of inconsistent alignment and reduced strength due to handheld installation, and existing plastic-based solutions suffer from lower durability and susceptibility to stripping, lacking a reliable metal-on-metal attachment.
Innovation Solution
A break-away bushing with an upper collar, lower sheath, and annular shoulder is used to maintain the securing member in an upright position within a fastener, allowing direct metal-on-metal contact upon installation by separating when the securing member is driven through, preventing stripping and enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plastic section is used to preset a threaded securing member, then the securing member can be preset in an attachment opening, but the strength, rigidity and durability are reduced and the connection is susceptible to fatigue and becoming loose
Solution Approach 1:
The bushing is divided into two functional segments: an upper collar that provides presetting support and a lower sheath that guides the securing member. This segmentation allows the plastic presetting function to be separated from the metal structural function, enabling both preset capability and strong metal-on-metal connection.
Solution Approach 2:
The breakaway bushing acts as an intermediary component during installation. It temporarily mediates between the securing member and the attachment opening, providing alignment and presetting support, then breaks away to allow direct metal-on-metal contact, thus enabling both easy presetting and strong final connection.
2Strength
If a metal-on-metal relationship is used between the fastener and securing member, then strength and rigidity are improved, but the metal surfaces are susceptible to stripping when preloaded
Solution Approach 1:
The bushing performs preliminary protective action by providing a soft, compliant interface during the presetting phase. It protects the metal surfaces from stripping while the securing member is being threaded in, then breaks away to allow the strong metal-on-metal connection to engage without the risk of stripping.
Solution Approach 2:
The bushing is designed as a disposable, low-cost component that sacrifices itself during installation. It provides temporary protection against stripping during presetting, then breaks away to enable the durable metal-on-metal connection, effectively using a cheap short-living object to protect the expensive durable components.
3Ease of operation
If handheld positioning is used to install fasteners, then installation flexibility is maintained, but the process is very time consuming and results in inconsistent fastener alignment
Solution Approach 1:
The bushing provides self-service alignment functionality. Its geometry automatically guides the securing member into proper alignment with the attachment opening, eliminating the need for manual positioning by the installer. This maintains installation simplicity while dramatically improving speed and consistency.
4Ease of operation
If a permanent plastic section is used for presetting, then the securing member can be held in position, but the connection easily becomes loose or damaged over time
Solution Approach 1:
The harmful plastic component is extracted from the final installed structure. The bushing provides necessary presetting support during installation, then breaks away and is removed, leaving only the durable metal-on-metal connection. This eliminates the long-term durability issues of plastic while retaining the presetting benefit during installation.
Data Source
AI summary
A bushing includes an upper collar with a lower sheath and an annular shoulder intermediate the collar and sheath. The collar has a plurality of spaced apart notches and the sheath has a plurality of spaced apart slits that may be circumferentially aligned with the notches. The sheath has a plurality of spaced apart ribs projecting outward circumferentially offset from the slit for assisting in maintaining the sheath within a hole in a fastener with the annular shoulder against the fastener. A securing member with an elongate shank extending from a head with a distal portion is maintained in the longitudinal opening in an upright position aligned with the hole. As the fastener is driven longitudinally through the opening and hole, force from the fastener causes the bushing to break away and yields direct contact between the securing member head against the top surface of the fastener.