Security Nut Ridge Geometry to Prevent Post-Tightening Loosening
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Solution Overview
Problem
Conventional security nuts and bolts require dedicated tools for tightening, limiting versatility and increasing costs, and they are not effective in preventing loosening once tightened.
Innovation Solution
Design of a security nut and bolt with torque transmission projections featuring inclined ridge lines and specific surface lengths, making it difficult to loosen them once tightened, using a general tool like a socket wrench, and incorporating features such as flanges and protrusions to prevent gripping by standard tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional security nuts and bolts use dedicated tools for tightening, then security against unauthorized loosening is improved, but versatility and cost are worsened
Solution Approach 1:
The security nut and bolt are designed to work with both dedicated security tools and standard wrenches/sockets. The torque transmission projection has surfaces that can engage with either type of tool, allowing the fastener to serve multiple functions - providing security when needed while maintaining compatibility with common tools for general use
2Reliability
If conventional security nuts and bolts use dedicated tools, then security is improved, but cost increases
Solution Approach 1:
By designing the torque transmission projection to accept both dedicated tools and standard wrenches, the invention eliminates the need for expensive dedicated tooling while maintaining security functionality. Users can rely on existing standard tools rather than investing in specialized equipment
3Reliability
If the torque transmission projection has a ridge line inclining toward the upstream side, then preventing loosening is improved, but tightening complexity may increase
Solution Approach 1:
The torque transmission projection features asymmetric geometry with a ridge line that inclines toward the upstream side (opposite to the tightening direction). This asymmetric design creates different engagement characteristics for tightening versus loosening, allowing easy tightening while preventing loosening through the directional bias of the inclined ridge
Data Source
AI summary
A nut and a bolt are provided, which make it difficult to be loosened once they have been tightened. A security nut includes: a nut body having an inside screw; and a plurality of torque transmission projections provided on an outer surface of the nut body along a circumferential direction. Each torque transmission projection has a torque transmission surface provided on an upstream side in a tightening direction of the security nut, and a release surface provided on a downstream side in the tightening direction of the security nut. A ridge line is formed between the release surface and the torque transmission surface, the ridge line inclining toward the upstream side of the tightening direction along the circumferential direction, from an advancing-direction end of the nut body to a retracting-direction end of the nut body.