Torque-Limiting Connector With Shear Pin Mechanism

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Solution Overview

Problem

Precision threaded RF connectors are prone to damage due to over-torquing, which can result in costly repairs or replacements, especially when used on expensive electronic equipment, as users often apply excessive torque in an attempt to achieve a better connection.

Innovation Solution

The implementation of a shear pin mechanism within the connector design that breaks when a sufficient torque force is applied, preventing further rotation and damage by decoupling the connector portions and allowing for safe disconnection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If users apply more torque to tighten the connector, then the electrical connection quality improves, but the connector and mating equipment may be damaged

Engineering Contradiction:
Improveelectrical connection qualityVSAvoiddamage to connector and equipment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The shear pin is pre-installed in the connector assembly at a predetermined torque threshold. Before actual use, the system is prepared with this protective mechanism already in place, so that when excessive torque is applied during connection, the shear pin automatically breaks to prevent damage to the expensive mating equipment. This preliminary preparation of the protective mechanism resolves the contradiction by enabling users to apply torque confidently while the pre-positioned shear pin ensures safety.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The shear pin acts as an intermediary sacrificial element between the user's tightening action and the connector/mating equipment. Instead of the torque directly affecting the precious mating connector on expensive equipment, the shear pin intercepts the excessive force and fails first, protecting the primary system. This intermediary mechanism allows the user to achieve tight connection without risking damage to the mating equipment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a torque wrench is used to prevent over-torquing, then damage to connectors is reduced, but the device complexity increases and proper usage must be ensured

Engineering Contradiction:
Improvedamage from over-torquingVSAvoidcomplexity of tightening process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The connector assembly performs its own protective function through the integrated shear pin mechanism. Instead of requiring an external torque wrench or complex control system to prevent over-torquing, the connector itself contains the protective mechanism that automatically activates when excessive force is applied. The system serves itself by having the shear pin break at the predetermined torque threshold, eliminating the need for external torque control devices and simplifying the overall system.

Inventive Principle:
Principle #25Self-service

3Strength

If the connector is designed with higher strength to resist over-torquing, then connection robustness improves, but the connector becomes more difficult to tighten and may still damage mating equipment

Engineering Contradiction:
Improveconnector strengthVSAvoidease of tightening
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connector assembly is segmented into distinct functional components with different strength characteristics. The shear pin is designed as a separate, weaker element compared to the main connector body and mating interface. This segmentation allows the overall assembly to have high strength for robust connection, while the specific shear pin component provides a controlled weak point that fails first under excessive torque, enabling easy tightening without risking damage to the strong mating equipment.

Inventive Principle:
Principle #1Segmentation

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

This solution effectively limits torque forces, preventing damage to the connectors and associated equipment by allowing the connector to break away when excessive torque is applied, thereby protecting the mating interface and reducing the risk of costly repairs.

Implementation Method 1

A shear pin is configured for engaging both the first and second cavities and spanning across the interface for joining the male and female portions together as a connector and includes a shear section aligned with the interface and configured for breaking when a sufficient torque force is applied between the male portion and the female portion

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP3430687B1Connector and cable with torque-limiting features
Publication Date: 2022.10.12 CARLISLE INTERCONNECT TECHNOLOGIES INC
  • EP3430687B1 patent drawingFigure 1
  • EP3430687B1 patent drawingFigure 2
  • EP3430687B1 patent drawingFigure 3

AI summary

A connector (10) includes separate portions that rotatably couple together and form a connector (10). The portions include elements for defining cavities (100, 102) and or slots, (280) therebetween that accept one or more shear elements (50, 282), such as shear pins (50, 282) for the purposes of coupling the separate portions together in forming a unitary connector. The connector (10) might be used between a cable (40) and another connector (44) or could form part of the connector on a cable (40). The shear element (50, 282) is configured for engaging the various portions and spanning across the interface (112) for joining the portions together. The shear element (50, 282) is configured for breaking when a sufficient torque force is applied between the connector portions.