Fastener Design for Inner Case Rotation Prevention
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Solution Overview
Problem
Existing physical quantity measuring devices face complexity in fixing the inner case to the outer case, which can lead to accidental breakage of wires due to circumferential rotation, and lack a simple mechanism to prevent such rotation.
Innovation Solution
A physical quantity measuring device design featuring a cylindrical outer case, a cylindrical inner case, and a fastener with a contact peripheral portion that engages with the outer case to prevent rotation, utilizing a guide and engaging portion to securely attach the inner case to the outer case, ensuring stability during transportation and use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner case is fixed to the outer case using welding and screwing methods, then the fixation reliability is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple fixation functions into a single integrated fastener component. This fastener simultaneously provides screwing engagement with the outer case, welding engagement with the inner case, and rotation prevention through its geometric design, thereby reducing structural complexity while maintaining fixation reliability
Solution Approach 2:
The fastener is designed as a multi-functional component that performs multiple roles: it secures the inner case to the outer case through engagement features, prevents circumferential rotation through its asymmetric geometry, and provides structural support. This universal design eliminates the need for separate fixation components
2Device complexity
If a simple fastening structure is used, then the device complexity is reduced, but the rotation prevention capability is insufficient
Solution Approach 1:
The fastener incorporates asymmetric geometric features including a tapered distal end and non-circular cross-sectional profiles. These asymmetric elements prevent circumferential rotation of the inner case relative to the outer case by creating a mechanical interference fit that only allows axial movement, not rotational movement
3Ease of operation
If the inner case is housed in the outer case with loose fit, then the ease of assembly is improved, but the stability during transportation deteriorates
Solution Approach 1:
The fastener is pre-configured with engagement features that automatically engage with corresponding features on the inner and outer cases during assembly. The tapered distal end of the fastener guides the assembly process, allowing easy insertion while ensuring proper alignment and secure engagement, thereby maintaining both assembly ease and transportation stability
Data Source
AI summary
A device includes: an outer case; an inner case; a cylindrical base having a distal end that penetrates through a cylinder of the outer case to be fixed to the outer case; and a fastener configured to be mounted on the distal end of the base, the fastener including: an exterior configured to be guided by a guide provided to the inner case; a fastener-side engaging portion engageable with the inner case; and a contact peripheral portion configured to be contact with the outer case to prevent the inner case from rotating relative to the outer case.