Security Fastener Shroud Retention for Anti-Theft Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing high security fasteners, such as locking wheel nuts and wheel bolts, face challenges in preventing unauthorized removal due to the lack of effective rotational retention mechanisms for the shroud or cap, allowing potential theft devices to engage and spin the shroud while the fastener body remains stationary, compromising security.
Innovation Solution
A fastener design featuring a shroud-receiving body portion with an inwardly deformed stop that radially overlaps an outwardly extending annular shoulder of the shroud, forming a shroud-retaining element that restricts the shroud's movement in axial directions, allowing the shroud to rotate freely relative to the fastener body under torque, thus preventing unauthorized removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shroud is freely rotatable on the fastener body, then the security against theft devices is improved, but the shroud may detach axially under vibration or impact
Solution Approach 1:
The retaining feature is segmented into multiple independent elements (protrusions on the shroud and corresponding recesses on the fastener body) that work together to provide both rotational freedom and axial retention. This segmentation allows the shroud to rotate independently while maintaining secure axial positioning.
Solution Approach 2:
The retaining feature acts as an intermediary mechanism between the shroud and fastener body, enabling the shroud to rotate freely while preventing axial detachment. The protrusion-recess interface serves as the mediating structure that reconciles the conflicting requirements of rotational freedom and axial retention.
2Stability of the object's composition
If the shroud is tightly retained on the fastener body, then axial detachment is prevented, but rotational freedom is restricted
Solution Approach 1:
The retaining feature provides localized retention at specific points (protrusions and recesses) while leaving the rest of the shroud-fastener interface free for rotation. This local quality approach allows the shroud to be constrained axially at discrete locations while maintaining rotational freedom elsewhere.
Solution Approach 2:
The retaining feature is designed to be dynamic rather than static, allowing the shroud to rotate freely while maintaining axial retention. The protrusion-recess interface accommodates rotational movement while preventing axial separation, creating a dynamic retention system that adapts to the shroud's rotational motion.
3Ease of manufacture
If conventional retention mechanisms are used, then manufacturing is simpler, but security against theft devices is reduced
Solution Approach 1:
The retaining feature merges the functions of rotational retention and axial retention into a single integrated structure. By combining these functions into one feature formed during the fastener body manufacturing process, the design achieves enhanced security without significantly increasing manufacturing complexity.
Solution Approach 2:
The retaining feature is self-forming during the fastener body manufacturing process, requiring no separate assembly steps or additional components. The protrusions and recesses are created inherently during forming operations, allowing the security feature to serve itself without requiring separate manufacturing operations.
Data Source
AI summary
An improved fastener comprising a fastener body orientated about a central axis and having a tool-engaging portion, a threaded fastening portion and a shroud-receiving portion; a shroud concentrically mounted in the shroud-receiving portion to rotate relative to the fastener body under an applied external torque and having an outwardly extending annular shoulder; the shroud-receiving portion comprising an inwardly deformed stop radially overlapping the outwardly extending annular shoulder of the shroud; and the deformed stop of the shroud-receiving portion and the annular shoulder of the shroud forming a shroud-retaining element restraining the shroud from movement in at least a first axial direction along the central axis.