Earthing Switch Worm Wheel Freewheel for Precise End Positioning
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Solution Overview
Problem
Existing disconnector or earthing switches lack a secure and easy operation mechanism, particularly for high-voltage applications, which can lead to unsafe handling and inefficient operation.
Innovation Solution
A high-voltage disconnector or earthing switch utilizing a rotatable drive shaft with a worm and a partially toothed worm wheel, allowing for axial movement between connected and disconnected positions, and a re-engagement device for precise torque transmission and freewheel function, providing audible feedback and safeguarding against excessive operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a motorized drive is used to operate the disconnector or earthing switch, then automation and productivity are improved, but the device requires end switches and complex control mechanisms to delimit traverse
Solution Approach 1:
The worm wheel mechanism provides automatic end-position detection and motor reversal without external end switches. The motor is directly connected to the worm wheel, and when the switching tubes reach their end positions, the worm wheel teeth disengage from the worm, automatically triggering the motor to reverse direction through the control unit. This self-service mechanism eliminates the need for separate end switch devices.
Solution Approach 2:
The worm wheel serves multiple functions simultaneously: it transmits torque from the motor to the switching tubes, provides mechanical advantage for operation, and acts as an end-position sensor that triggers motor reversal. This multi-functionality consolidates what would otherwise require separate components (torque transmission mechanism and end-position detection system) into a single integrated element.
2Device complexity
If manual operation is used to define end positions, then device complexity is reduced, but operation security and precision are insufficient
Solution Approach 1:
The worm wheel teeth provide mechanical feedback to the control unit when they disengage from the worm at end positions. This feedback signal automatically triggers the motor to reverse direction, ensuring precise and reliable end-position definition without requiring complex manual intervention or additional sensing mechanisms.
3Ease of operation
If a conventional freewheel mechanism is used, then ease of operation is improved, but the mechanism is influenced by environmental factors and lubricant aging
Solution Approach 1:
The patent replaces the conventional friction-based freewheel mechanism with a positive engagement system using worm and worm wheel teeth. This mechanical substitution eliminates reliance on friction and lubricants, providing a more reliable and environmentally stable operation that is not affected by temperature, humidity, or lubricant degradation.
4Force
If the worm wheel is fully toothed for continuous engagement, then torque transmission is improved, but the ability to provide end-position feedback and allow motor reversal is lost
Solution Approach 1:
The worm wheel is segmented into two functional zones: a toothed portion for torque transmission during normal operation and a toothless portion at the end positions for disengagement and feedback. This segmentation allows the same component to perform both torque transmission and end-position detection functions without requiring separate mechanisms.
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 enables secure, efficient, and precise operation of high-voltage disconnector or earthing switches, ensuring safe handling and preventing excessive operation, while maintaining mechanical decoupling and reducing environmental and aging influences on the freewheel mechanism.
Implementation Method 1
a rotatable drive shaft (4) comprising a worm (7) and configured for operating the earthing switch and the three respective switching tubes (3)
Implementation Method 2
a partially toothed worm wheel (5) configured for translating a rotation of the worm (7) into the axial movement of the three switching tubes (3) between the connected position and the disconnected position
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a disconnector or earthing switch (1) for connecting three conductors (2) of different phases to a respective switching tube (3), comprising a rotatable drive shaft (4) comprising a worm (7) and configured for operating the disconnector or earthing switch (1), the three respective switching tubes (3), which are arranged axially together movable between a connected position configured for connecting the three conductors (2) and a disconnected position configured for not connecting the three conductors (2), a partially toothed worm wheel (5) configured for translating a rotation of the worm (7) into the axial movement of the three switching tubes (3) between the connected position and the disconnected position, whereby the partially toothed worm wheel (5) is unengaged with the worm (7) in the connected position and the disconnected position, and a re-engagement device (6) configured for again engaging the partially toothed worm wheel (5) with the worm (7) in the connected position and the disconnected position.