Spring-Actuated Circuit Interrupter Toggle Mechanism
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Solution Overview
Problem
Existing circuit interrupters with cam-based mechanisms require excessive force and are unreliable due to extensive linkages, making them inefficient and unreliable in switching between ON, OFF, and TRIP positions.
Innovation Solution
A circuit interrupter design featuring a spring that extends between the handle and operating linkage, allowing independent velocity and acceleration of the contact arm, reducing mass and inertia, and utilizing a toggle point to convert spring tension into kinetic energy for rapid contact movement, thereby reducing the effort needed to switch positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a cam-based mechanism is used to switch the circuit interrupter among positions, then the device can achieve position switching functionality, but the device complexity increases due to extensive linkages and the force required to move the mechanism increases
Solution Approach 1:
The patent removes the cam-based mechanism and extensive linkages from the system, replacing them with a direct spring-actuated system. The spring 40 directly connects the handle 34 to the contact arm 66, eliminating the need for intermediate cam-based components and reducing overall device complexity while lowering the force required for operation.
Solution Approach 2:
Instead of using a cam mechanism that requires external force to drive the entire rotation, the patent inverts the approach by using a spring that stores energy during part of the rotation and releases it to automatically complete the motion. The spring 40 is stretched during initial handle rotation and then contracts to pull the contact arm through the remaining travel, reversing the traditional force application model.
2Reliability
If a cam-based mechanism with extensive linkages is used, then position switching can be achieved, but the reliability of the circuit interrupter decreases
Solution Approach 1:
The patent eliminates the cam-based mechanism and extensive linkages that cause reliability issues, replacing them with a simple spring-actuated system. The direct connection between the spring 40, handle 34, and contact arm 66 removes multiple potential failure points associated with cam-based linkages.
Solution Approach 2:
The patent introduces dynamic elements including a movable roller 64 that travels along a curved path 84, and a spring 40 that dynamically changes its tension state. This dynamic system allows the mechanism to adapt during operation, with the roller's curved path providing controlled motion transformation and the spring providing dynamic force adjustment, improving reliability over static cam-based systems.
3Speed
If the spring passes the toggle point quickly, then the contact arm moves rapidly from OPEN to CLOSED position, but the velocity of the contact arm becomes dependent on the handle velocity
Solution Approach 1:
The patent employs dynamic elements including a movable roller 64 that travels along a curved path 84 and a spring 40 that changes its mechanical advantage ratio as it passes through the toggle point 42. This dynamic system allows the contact arm 66 to achieve rapid movement independent of handle velocity, as the spring's stored energy and the curved path geometry create a mechanical amplification effect that decouples the velocities of the handle and contact arm.
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 design enhances the reliability and efficiency of the circuit interrupter by reducing the force required to move between positions, improving performance, and reducing the effort needed to manually operate the handle, while also minimizing the mass and cost of the mechanism.
Implementation Method 1
the spring being structured to bias the contact arm from the OPEN position to the CLOSED position when the mechanism moves from the OFF position to the ON position
Implementation Method 2
Once the spring passes the toggle point, the potential energy of the spring is converted to kinetic energy that rapidly moves the contact arm from the OPEN position to the CLOSED position
Data Source
AI summary
A circuit interrupter includes a handle, an operating linkage, and a spring that are situated on a housing, with the spring extending between the handle and the operating linkage. The circuit interrupter is movable among an ON position, an OFF position, and a TRIP position, and the operating linkage includes a contact arm that is pivotable with respect to the housing to move a movable contact between an OPEN position and a CLOSED position with respect to a stationary contact. The handle has a toggle point, and when the spring is situated at a first side of the toggle point, the spring biases the contact arm to the ON position. When the spring is situated at a second side of the toggle point, the spring biases the contact arm to the OFF position or the TRIP position.