Adjustable Connecting Rod Anti-Rotation Key for Vibration Locking
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Solution Overview
Problem
Existing length-adjustable connecting rods with anti-rotation systems are prone to length loss due to vibrations and have a bulky, mass-intensive locknut that increases on-board mass, especially at larger diameters.
Innovation Solution
A connecting rod design featuring a key with three parts that provides rotational immobilization between the fastening head and body, using a connection pin and teeth for secure alignment, which reduces the risk of length adjustment loss and minimizes mass impact by decoupling volume and mass from the rod's diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locknut is used as the anti-rotation system, then the connecting rod can maintain its adjusted length, but the locknut becomes bulky and increases on-board mass, especially when the connecting rod has a large diameter
Solution Approach 1:
The anti-rotation system is segmented into multiple functional elements: a key with first and second parts, a connection pin, and a retaining element. This segmentation replaces the single bulky locknut with distributed, smaller components that collectively achieve the same anti-rotation function while reducing overall mass
Solution Approach 2:
The key acts as an intermediary element between the threaded rod and the body, providing rotational immobilization without requiring direct contact between large components. The connection pin and retaining element further mediate the connection, allowing the system to maintain adjusted length with smaller, lighter parts
2Reliability
If a locknut is used as the anti-rotation system, then the connecting rod can maintain its adjusted length, but the locknut can become unscrewed due to vibrations causing loss of adjustment
Solution Approach 1:
The retaining element is installed beforehand to prevent the connection pin from disengaging under vibratory loads. This proactive measure ensures that the anti-rotation system remains intact and functional throughout operation, preventing loosening before it can occur
Solution Approach 2:
The connection pin serves as an intermediary that positively engages with the key and body, creating a mechanical interlock that resists vibratory forces. This intermediary connection is more vibration-resistant than the friction-based holding of a locknut
3Reliability
If the anti-rotation system is designed to be secure against vibrations, then reliability improves, but the system becomes more complex and bulky
Solution Approach 1:
The system is divided into simple, discrete components (key, connection pin, retaining element) that can be manufactured and assembled using standard processes. Each component has a single, clear function, reducing overall system complexity despite achieving superior vibration resistance
Solution Approach 2:
The key's geometry itself provides the anti-rotation function through its shaped first and second parts, eliminating the need for additional complex locking mechanisms. The system uses the inherent properties of its components rather than adding complexity to achieve vibration resistance
Data Source
AI summary
A connecting rod with a body, first and second fastening heads provided at each end of the body and connected by first and second connection systems to first and second elements, the first fastening head comprising an extension which is screwed into a housing of the body to adjust the length of the connecting rod. The connecting rod includes an anti-rotation system with a key, positioned astride the first fastening head and the body, which has a first part cooperating with the body so as to be rotationally immobilized with respect to the body and also a second part cooperating with the first fastening head and the first connection system so as to be immobilized with respect to the first fastening head.