Non-Concentric Manual Operation Device for Low Voltage Switching Apparatus
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Solution Overview
Problem
Large capacity low voltage switching apparatuses require excessive manual operating force due to concentric rotation centers, leading to operational difficulties and safety risks, especially for products with rated currents over 4000 A.
Innovation Solution
A manual operation device with a non-concentric rotation center design, featuring an operating handle, pawl, ratchet wheel, and reset springs, which reduces the required manual operating force by distributing torque effectively through a ratchet mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the rotation center of the operating handle and the rotation center of the energy storage shaft are made concentric, then the structure is compact and easy to realize, but the manual operating force becomes excessively large for large capacity switching apparatuses
Solution Approach 1:
The patent applies asymmetry by deliberately designing the operating handle and energy storage shaft with non-concentric rotation centers. The operating handle rotates about a mounting shaft that is offset from the energy storage mechanism's rotation shaft, creating an asymmetric mechanical advantage that reduces the manual operating force required while maintaining structural feasibility
Solution Approach 2:
The patent introduces a dimensional change by adding a second rotation axis (mounting shaft) that is spatially separated from the original rotation shaft. This creates a lever arm effect where the operating handle rotates about the mounting shaft, which is positioned at a different location, thereby reducing the force required at the handle while still achieving the necessary torque at the energy storage mechanism
2Device complexity
If a concentric structure is used for the operating handle, then the structure is simple, but the required manual operating force exceeds safety limits for rated currents over 4000 A
Solution Approach 1:
The patent resolves the safety issue by implementing asymmetric positioning of the mounting shaft relative to the energy storage shaft. This asymmetric arrangement creates a mechanical advantage that reduces the manual operating force to within safe limits (under 250N as per IEC standard) while maintaining operational reliability for large capacity switching apparatuses with rated currents over 4000 A
Solution Approach 2:
The patent introduces an intermediary element - the mounting shaft - that acts as a mediator between the operating handle and the energy storage mechanism. This intermediary shaft is positioned offset from the energy storage shaft, creating a lever arm that reduces the force transmission from the handle to the energy storage mechanism, thereby ensuring operational safety
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 solution significantly reduces the manual operating force needed, making operations easier, safer, and more reliable for large capacity switching apparatuses by enhancing torque distribution without compromising safety or reliability.
Implementation Method 1
A reset torsion spring is arranged between the second fixing plate and the fixing groove
Implementation Method 2
One end of a first reset spring is connected to the top end of the pawl, the other end of the first reset spring is connected to the operating handle
Implementation Method 3
One end of a second reset spring is connected to the bottom end of the stop detent, the other end of the second reset spring is fixed on the mounting plate
Implementation Method 4
A ratchet wheel is rotatably mounted on the rotation shaft, the bottom end of the pawl is engaged with an intertooth position of the ratchet wheel
Data Source
AI summary
The present invention discloses a manual operation device for low voltage switching apparatus. An operating handle is provided with a fixing groove. The fixing groove is matched with a second fixing plate, the second fixing plate is placed in the fixing groove. A reset torsion spring is arranged between the second fixing plate and the fixing groove. A pawl is rotatably mounted on the second fixing plate through a fixing pin, the pawl rotates about the fixing pin. One end of a first reset spring is connected to the top end of the pawl, the other end of the first reset spring is connected to the operating handle. The operating handle i mounted on a mounting shaft of an operating mechanism of the low voltage switching apparatus. A mounting plate is provided with a rotation shaft, the rotation shaft is the rotation shaft of an energy storage mechanism of the low voltage switching apparatus. The mounting shaft and the rotation shaft are not concentric. A ratchet wheel is rotatably mounted on the rotation shaft, the bottom end of the pawl is engaged with an intertooth position of the ratchet wheel. A stop detent is provided on the bottom of the mounting plate, the stop detent is rotatably mounted on the mounting plate. The top end of the stop detent is engaged with an intertooth position of the ratchet wheel. One end of a second reset spring is connected to the bottom end of the stop detent, the other end of the second reset spring is fixed on the mounting plate.