Drive Shaft Disconnector With Shear Coupler for Torsional Overload
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Solution Overview
Problem
Existing systems fail to effectively decouple a driving mechanism from rotating equipment in the event of failure, leading to potential damage and debris generation due to metal-on-metal contact during torsional overload.
Innovation Solution
A disconnector system with a shear coupler and actuator mechanism that selectively decouples the rotatable shaft components upon torsional overload, using a meltable element and biasing elements to prevent damage and debris formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive shaft remains connected during failure, then the structural integrity is maintained, but damage and debris generation occur due to metal-on-metal contact during torsional overload
Solution Approach 1:
The drive shaft is segmented into multiple portions (first shaft portion, intermediate shaft portion, second shaft portion) that can separate from each other. The shear coupler connects these segments and can be selectively sheared to disconnect the shaft, preventing damage while maintaining structural integrity through controlled segmentation.
Solution Approach 2:
The shear coupler is pre-configured with a weakened region that will fail at a predetermined torque threshold. This preliminary preparation ensures that when torsional overload occurs, the disconnect happens automatically at the predetermined threshold, preventing damage before it occurs.
2Object-generated harmful factors
If a shear coupler is used to disconnect the drive shaft, then debris generation is reduced, but the device complexity increases due to additional components
Solution Approach 1:
The intermediate shaft portion is extracted as a separate component with a shear coupler that can be selectively removed or sheared. This extraction allows the harmful intermediate portion to be separated from the drive shaft system, preventing debris generation while managing complexity through modular design.
Solution Approach 2:
The shear coupler's torque threshold parameter is designed to be lower than the damage threshold of the drive shaft. By changing this critical parameter, the system ensures that the coupler fails first under overload conditions, preventing debris generation from shaft damage while keeping the overall system relatively simple.
3Reliability
If the disconnector system is activated, then the separation of shaft components is reliable, but the system requires additional control mechanisms
Solution Approach 1:
The shear coupler is designed to automatically activate the disconnector system when the predetermined torque threshold is exceeded. The system serves itself by using the overload condition directly to trigger the separation, eliminating the need for external control mechanisms while ensuring reliable separation.
Solution Approach 2:
The control mechanism is replaced by a purely mechanical shear-based activation system. Instead of using sensors, actuators, or electronic controls, the system uses the mechanical overload itself to shear the coupler and activate separation, reducing control complexity while maintaining reliability.
4Reliability
If the meltable element is used to prevent actuator movement, then protection against overload is provided, but the system complexity increases
Solution Approach 1:
The meltable element utilizes phase transition (melting) at a predetermined temperature to automatically prevent actuator movement. When the temperature threshold is exceeded, the element melts and physically blocks the actuator, providing overload protection through a simple phase change rather than complex control mechanisms.
Solution Approach 2:
The meltable element acts as an intermediary between the thermal overload condition and the actuator mechanism. It mediates the protection function by translating thermal overload into physical actuator blocking through its phase transition, simplifying the overall control system while ensuring reliable protection.
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
The disconnector system reliably separates the rotatable shaft components, preventing damage and debris generation during failure, ensuring safe operation and reducing secondary damage.
Implementation Method 1
a shear coupler configured to shear at a predetermined torque threshold to define a first sheared portion and a second sheared portion
Implementation Method 2
a biasing member disposed in the cavity and arranged to separate the first sheared portion from the second sheared portion
Implementation Method 3
a meltable element disposed between the housing and the actuator body, the meltable element being in thermal communication with the housing and positioned to prevent a movement of the actuator away from the disconnector mechanism
Data Source
AI summary
A disconnector system for disconnecting a drive shaft of a drive mechanism from rotating equipment, upon a failure of the drive mechanism or rotating equipment, includes a disconnector mechanism having a disconnector shaft disposed in a casing and moveable relative thereto, between a first position and a second position, and a cam surface on a distal end of the arm configured to engage a slidable coupler. The movement of the disconnector shaft can be triggered by an operation of a solenoid, or by a displacement of the solenoid responsive to a melting of a meltable element.