Pull-Pull Linkage for High Voltage Circuit Breaker
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Solution Overview
Problem
Conventional rotary or push-pull linkages in high voltage dead tank circuit breakers introduce lag and require increased weight and energy due to larger pole spreads, leading to potential buckling issues in compression configurations.
Innovation Solution
A pull-pull linkage structure with levers and connection rods maintained in tension using close and open springs, allowing for simultaneous actuation of pole assemblies while minimizing rod size and energy requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional rotary or push-pull linkage is used to connect pole assemblies, then the circuit breaker can selectively open or close electrical connections, but lag is introduced into the breaker operation and pole spread increases
Solution Approach 1:
The patent inverts the conventional push-pull linkage configuration to a pull-pull configuration. Instead of one rod pushing and another being pushed (compression-tension), both rods are designed to be in tension only. This is achieved by positioning the operating mechanism above the pivot points and using gravity to maintain tension in the rods, eliminating the compression phase that causes buckling and lag in conventional designs.
Solution Approach 2:
The patent changes the mechanical state parameter of the linkage rods from alternating compression-tension (conventional) to tension-only (invention). By ensuring both rods remain in tension through the pull-pull configuration and gravitational loading, the system eliminates the buckling phenomenon and associated lag that occurs in compression members, thereby improving operational speed and reducing time loss.
2Loss of time
If the linkage is made larger to prevent lag in conventional configurations, then lag is reduced, but weight and energy requirements increase
Solution Approach 1:
By inverting to a pull-pull configuration where both rods are in tension, the patent eliminates the need for oversized compression-resistant members. Tension rods can be much lighter and more slender than compression rods of the same length, as they do not suffer from buckling. This allows the linkage to be made lighter while maintaining or even improving operational responsiveness.
Solution Approach 2:
The patent changes the stress state parameter from compression-dominant to tension-dominant, which fundamentally alters the required rod dimensions and material usage. Tension members require significantly less cross-sectional area and material than compression members to achieve the same structural integrity, directly reducing weight without compromising lag prevention.
3Productivity
If the linkage is made larger to prevent lag, then operational speed improves, but the energy required of the operating mechanism increases
Solution Approach 1:
The inverted pull-pull configuration eliminates the need for large, energy-intensive compression members. Since both rods work in tension only, the operating mechanism can be smaller and require less energy to actuate the same pole assemblies, while maintaining improved operational speed due to reduced mass and eliminated buckling delays.
Solution Approach 2:
By changing the stress parameter from compression to tension, the patent reduces the energy requirements of the operating mechanism. Tension rods have lower moment of inertia and mass than equivalent compression rods, requiring less energy to accelerate and decelerate during operation, thereby reducing the energy burden on the operating mechanism while maintaining high productivity.
4Force
If push-pull configuration is used, then linkage can transmit force, but compression over long time spans leads to buckling
Solution Approach 1:
The patent inverts the force transmission mode from push-pull (compression-tension) to pull-pull (tension-tension). By ensuring both rods remain in tension through the operating mechanism positioning and gravitational loading, the system completely eliminates the compression phase that causes buckling, thereby maintaining reliable force transmission without buckling risks.
Solution Approach 2:
The patent changes the stress state parameter from compression-tension alternation to tension-only continuity. This parameter change fundamentally eliminates the buckling phenomenon, as buckling only occurs in compression members. The rods remain in continuous tension throughout operation, ensuring high reliability and eliminating the compression-related failure mode.
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 reduces lag time, shipping weight, and energy needs by maintaining connection rods in tension, preventing buckling and ensuring a compact, efficient operation.
Implementation Method 1
At least one spring structure is coupled to the lever. The spring structure includes at least one open spring providing a spring force on the lever for opening the electrical contact while maintaining the connection rod in tension.
Implementation Method 2
at least one open spring providing a spring force on the lever
Implementation Method 3
At least one connection rod is coupled to the lever and is associated with a close spring for closing the electrical contact.
Data Source
AI summary
Linkage structure is provided for connection between an operating mechanism and at least one actuating assembly of a circuit breaker for opening and closing a movable electrical contact of a pole assembly associated with the actuating assembly. The linkage structure includes at least one lever constructed and arranged to connect with the at least one actuating assembly. At least one connection rod is coupled to the lever and associated with a close spring for closing the electrical contact. At least one spring structure is coupled to the lever. The spring structure includes at least one open spring providing a spring force on the lever for opening the electrical contact while maintaining the connection rod in tension.