Security Wheel Fastener With Free-Spinning Shroud Coupling
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Solution Overview
Problem
Existing fasteners used to secure wheels to vehicle axles lack sufficient security measures, allowing unauthorized removal with conventional tools and theft devices, despite having unique key patterns and shrouds.
Innovation Solution
A fastener design featuring a shroud that rotates independently of the fastener body under torque, coupled by a torque coupler with a unique key pattern, preventing unauthorized rotation by allowing the shroud to spin freely without rotating the fastener body, requiring a matching key to engage both the shroud and fastener body for rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shroud is fitted over the fastener to prevent gripping the sidewalls, then security against theft devices is improved, but the fastener cannot be installed or removed with conventional tools
Solution Approach 1:
The fastener system is divided into separate functional components: a stationary fastener body that engages the wheel stud, and a rotating shroud that interfaces with installation tools. This segmentation allows the shroud to rotate independently during installation/removal while the fastener body remains secure, resolving the contradiction between tool accessibility and theft prevention.
Solution Approach 2:
The shroud acts as an intermediary element between the installation tool and the fastener body. It provides the external engagement surface for conventional tools while transmitting rotational force to the fastener body only when properly aligned with the keyway, thus enabling easy installation while maintaining security.
2Reliability
If a unique key pattern is used on the fastener end face, then security against conventional tools is improved, but the fastener requires a specialized security tool for installation
Solution Approach 1:
The shroud serves multiple functions: it provides a universal engagement surface for conventional installation tools (wrenches, sockets), acts as a security feature by obscuring the keyway, and transmits torque to the fastener body. This multi-functionality eliminates the need for specialized security tools while maintaining security against conventional tools.
Solution Approach 2:
The security keyway feature is extracted from the external surface and placed inside the shroud, making it invisible and inaccessible to conventional tools. The shroud's external cylindrical surface provides a universal interface for standard tools, separating the security function from the tool interface function.
3Reliability
If the shroud is made free-spinning to prevent torque transmission, then security against theft devices is improved, but the fastener cannot be installed or removed
Solution Approach 1:
The shroud's rotational behavior is made dynamic rather than static: it rotates freely during unauthorized attempts (providing security) but engages with the fastener body's keyway during proper installation (enabling operation). The interaction between the shroud's internal keyway and the fastener body's external key pattern creates conditional torque transmission.
Data Source
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AI summary
A fastener body having a key-engaging portion, a threaded fastening portion, and a shroud-receiving body portion; a shroud concentrically and rotationally mounted on the shroud-receiving body portion and rotatable relative to the fastener body; a torque coupler comprising a key portion rotationally engaging the key-engaging portion of the fastener body and a shroud-engaging portion rotationally engaging a coupler-engaging portion of the shroud, and the shroud having a tool-engaging portion to which an external driving torque may be applied; wherein the coupler is operatively configured to be in rotatable relationship with both the key-engaging portion of the fastener body and the coupler-engaging portion of the shroud such that the fastener body will rotate about the central axis with rotation of the shroud about the central axis under an external driving torque applied about the central axis to the tool-engaging portion of the shroud at a design installation torque.