Torque-Limiting Fastening Sleeve for Locknut Connectors
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Solution Overview
Problem
Existing mechanical fastening systems require additional tools for tightening connectors to a predetermined torque, and integrated torque-limiting mechanisms in connectors are limited by wear and lack of replaceability.
Innovation Solution
A fastening aid comprising a sleeve element with an engaging structure that attaches to a locknut, allowing screwing up to a predetermined torque and preventing further rotation by slipping over the locknut when exceeded, enabling manual operation without additional tools and easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional torque wrench is used to tighten connectors to a predetermined torque, then the connector can be fastened with defined torque, but additional tools and accessories are required which may get lost and render the torque wrench unusable
Solution Approach 1:
The torque limiting mechanism is merged directly into the connector body by integrating a torque-defining element (such as a breakable retaining ring or deformable feature) into the connector structure. This eliminates the need for separate torque wrenches and accessories, as the connector itself contains the torque control functionality.
Solution Approach 2:
The connector performs its own torque limiting function through self-contained mechanisms such as breakable retaining rings that fracture at predetermined torque values or deformable features that yield when excessive torque is applied. The connector serves itself by automatically limiting torque without requiring external tools.
2Measurement precision
If a fully integrated plastic locknut with torque restriction is provided in the connector, then the torque can be restricted to a predetermined value, but the number of screwing operations is limited due to wear of the locknut and replacement is not possible
Solution Approach 1:
The torque limiting function is separated from the locknut structure. Instead of making the entire locknut plastic and integrated, a separate torque-defining element (such as a metal retaining ring or separate torque-limiting feature) is introduced that can be independently replaced while keeping the locknut itself reusable.
Solution Approach 2:
The torque-defining element is designed to be replaceable and can be discarded after use (such as a breakable retaining ring that fractures once), while the main locknut and connector body are recovered and can be reused for subsequent operations. This separates the consumable torque-limiting component from the reusable structural components.
3Measurement precision
If additional torque limiting mechanisms are integrated into the connector, then the predetermined torque can be maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The torque-defining element is designed as a simple, inexpensive, disposable component (such as a thin retaining ring or deformable feature) that can be easily manufactured and replaced. This keeps the cost low while providing reliable torque limiting, as the element is discarded after a single use rather than being part of a complex reusable mechanism.
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
Enables manual fastening at a defined torque without additional tools, allows easy attachment and detachment from connected components, and facilitates cost-efficient production with the option to replace worn aids without decoupling from counter parts.
Implementation Method 1
The engaging structure is configured to engage with an external structure of the locknut, and the fastening aid is configured to prevent screwing of the fastener by the engaging structure being configured to slip over the external structure of the locknut when the predetermined torque is exceeded.
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
A fastening aid for screwing a fastener having a locknut by rotating the fastener around a rotation axis with a predetermined torque includes a sleeve element being attachable around the locknut along the rotation axis, an engaging structure provided at an inner surface of the sleeve and configured to engage with the locknut when the sleeve is attached around the locknut, a clasp element for reversibly closing the sleeve element to a closed state for attaching the sleeve around the locknut, and for reversibly opening the sleeve element to an opened state for detaching the sleeve from the locknut. The fastening aid is configured to allow screwing of the fastener around the rotation axis when exposed to a torque smaller than or equal to the predetermined torque and to prevent screwing the fastener around the rotation axis when the predetermined torque is exceeded.