Multi-Patch Threaded Fastener for Vibration-Resistant Sealing
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Solution Overview
Problem
Threaded fasteners in applications with vibrations or impacts tend to loosen or unintentionally remove due to rotational forces, leading to damage and increased maintenance costs, as existing solutions like single nylon patches or adhesives are either insufficient for thread-sealing applications or slow down manufacturing processes.
Innovation Solution
A multi-patch threaded fastener with two or more polymer patches spaced along the shank, which wedge against mating components to enhance retention strength by promoting metal-to-metal contact, manufactured using a process where the fastener is preheated and coated with melted polymer material from fixed nozzles without rotation, allowing for higher processing rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single nylon patch is deposited along the threaded portion of the fastener, then retention strength is improved, but the fastener cannot provide adequate thread-sealing capability
Solution Approach 1:
The patent divides the patch configuration into multiple discrete patches positioned at specific locations along the threaded portion. Instead of a single continuous patch, multiple separate patches are applied to different circumferential positions and/or axial locations, allowing each patch to serve specific functions (retention at some locations, sealing at others) without compromising overall performance
Solution Approach 2:
Different regions of the fastener are given different properties through selective patch placement. Some areas have patches for retention strength while other areas have patches for sealing capability. The patches are positioned to create localized functions - for example, patches at certain angular positions provide sealing while patches at other positions provide retention biasing
2Adaptability or versatility
If the threaded fastener is rotated during nylon powder deposition to form a 360 degree patch, then thread-sealing capability is improved, but manufacturing productivity decreases significantly
Solution Approach 1:
The 360-degree coverage is achieved through multiple discrete patches positioned at different angular locations rather than a single continuous patch requiring full rotation. This allows the fastener to remain stationary during deposition while multiple nozzles or a multi-pass process applies patches at specific positions, eliminating the need for slow rotation during deposition
Solution Approach 2:
The patch positions are pre-determined and pre-positioned on the fastener before deposition begins. The deposition system is configured with nozzles positioned at predetermined locations corresponding to desired patch positions, allowing material to be deposited directly at the correct locations without requiring fastener rotation to bring different areas into position
3Strength
If adhesive is applied to the threaded portion of the fastener, then retention strength is improved, but machine down time increases due to curing time and adhesive cannot be reapplied
Solution Approach 1:
The patent uses a reusable thermoplastic patch material instead of a consumable adhesive. The thermoplastic patches can be repeatedly applied and removed multiple times without degradation of the fastener or loss of effectiveness, whereas adhesive is single-use and requires reapplication. This makes the patch system economically viable for repeated insertions and removals
Solution Approach 2:
The patch material undergoes reversible phase changes between solid and molten states through temperature control. During application, the thermoplastic material is heated above its melting point to become flowable for deposition, then cools to solidify and provide retention strength. This reversible parameter change allows the same material to be repeatedly applied and removed without permanent chemical bonding like adhesive
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 multi-patch configuration significantly increases retention strength and resistance to loosening, enabling faster manufacturing while maintaining high processing rates, and provides a sealing effect over a greater area compared to single-patch solutions.
Implementation Method 1
a threaded fastener is preheated to a predetermined temperature and conveyed past an applicator
Implementation Method 2
the nylon melts, due to the temperature of the threaded fastener, to form the patch
Data Source
Figure 1
AI summary
A multi-patch threaded fastener includes a shank having a threaded portion and two or more polymer patches disposed on the shank. The two or more polymer patches are configured to wedge against a mating threaded component to promote contact between non-patched threaded portions of the shank and the mating threaded component to resist removal from the mating threaded component. A method of making the multi-patch threaded fastener includes positioning two or more nozzles for dispensing a patch material at locations corresponding to desired patch locations on the shank, conveying the shank past two or more nozzles, and dispensing the patch material from each nozzle onto the shank to form the two or more polymer patches on the shank.