Auxiliary Contact Actuator with Bistable Spring Decoupling
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Solution Overview
Problem
Existing actuating devices for auxiliary contacts in electrical switching devices are imprecise due to long kinematic chains and bouncing shocks during main contact opening and closing, leading to incomplete travel and faulty switching, resulting in erroneous position indication.
Innovation Solution
A device with a telescopic rod and bistable spring mechanism that decouples the main contact drive shaft from the auxiliary contact drive shaft using an incomplete connection and a bistable spring system, ensuring precise positioning and reliable switching by isolating the auxiliary contacts from main contact system variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a long kinematic chain is used to connect the main contact control system to the auxiliary contacts, then the auxiliary contacts can be actuated, but the switching precision deteriorates due to mechanical play and incomplete travel
Solution Approach 1:
The patent divides the control system into two independent parts: the main contact control system and the auxiliary contact actuating device. The auxiliary contacts are actuated by a separate crank mechanism with its own restoring spring, rather than being directly controlled by the main contact system. This segmentation eliminates the accumulation of mechanical errors from a long kinematic chain and ensures precise switching independent of main contact variations.
2Loss of information
If the main contact control system is used to actuate auxiliary contacts, then the auxiliary contacts can signal the main contact state, but bouncing shocks during main contact operation cause erroneous switching
Solution Approach 1:
The patent introduces a crank mechanism with a restoring spring as an intermediary between the main contact system and the auxiliary contacts. This intermediary absorbs the bouncing shocks from the main contacts through its own elastic element, preventing these harmful vibrations from directly affecting the auxiliary contact switching. The crank acts as a buffer that smooths out the mechanical disturbances while still transmitting the positional information.
3Ease of operation
If many parts are set in motion with a long kinematic chain, then the auxiliary contacts can be actuated, but the device complexity increases
Solution Approach 1:
The patent combines the auxiliary contact actuating crank with the main contact control shaft, so that both systems share a common rotational axis. This merging allows the auxiliary contacts to be actuated through the same rotational motion that controls the main contacts, eliminating the need for separate actuating mechanisms and reducing overall device complexity while maintaining independent and precise control.
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 provides reliable and precise switching of auxiliary contacts, independent of main contact system variations, reducing bouncing and mechanical play, and ensuring accurate indication of main contact states through a shorter, more precise kinematic chain.
Implementation Method 1
a device with a telescopic rod and bistable spring mechanism
Implementation Method 2
bistable spring mechanism that decouples the main contact drive shaft from the auxiliary contact drive shaft
Data Source
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AI summary
The device (D) has a connecting rod connected to a drive shaft (1) and a crank (4) at ends. The crank for actuating auxiliary contacts is mounted to rotate relative to a support of the device between open and closed positions of main contacts of the device. A mechanical disconnect unit partially disconnects the shaft from the crank in vicinity of the positions. A telescopic spring device drives the crank toward the open/closed position when the shaft and the crank are disconnected. The crank is positioned on stop forming parts (10, 11) of a fixed support of a frame of the device.