Quick-Locking Fuse Circuit Breaker With Partial Rotation Mechanism
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Solution Overview
Problem
Existing switch-disconnectors require precise and time-consuming gestures for screwing and unscrewing the fuse insert, and it is difficult to determine if the fuse is sufficiently screwed in, especially in noisy environments, due to the need for precise thread control and audible cues that may be masked.
Innovation Solution
A switch-disconnector design with a housing that allows the fuse insert to be quickly locked in place with a partial revolution of less than or equal to 270°, using lugs and grooves with helical ramps for precise guidance and locking, and a recessed seat with an elastic member to ensure secure engagement, along with a conductive tab and insulating ribs for safety and visibility indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuse insert is screwed in using traditional threading, then reliable electrical contact is established, but the operation becomes time-consuming and requires precise gestures
Solution Approach 1:
The threading path is segmented into a limited angular range (maximum 270°) with distinct zones: a helical ramp portion for engagement and a recessed seat for final positioning. This segmentation allows the fuse insert to be quickly engaged without requiring a complete 360° rotation, reducing insertion time while maintaining reliable electrical contact.
Solution Approach 2:
Instead of requiring a full threading cycle, the invention uses partial action by limiting the screwing operation to a maximum of 270° rotation. The helical ramp provides sufficient threading engagement within this partial rotation to ensure reliable electrical contact, eliminating the need for excessive rotational movement.
2Reliability
If traditional threading is used, then the fuse insert can be secured, but precise dimensional control and lubrication are required to minimize tightening effort
Solution Approach 1:
The helical ramp is pre-formed as an integral part of the cavity wall, providing a built-in threading path that guides the fuse insert during insertion. This preliminary preparation of the threading path eliminates the need for precise dimensional control of removable threads and removes the requirement for lubrication, simplifying manufacturing while ensuring secure engagement.
Solution Approach 2:
The threading function is merged with the cavity wall structure itself. The helical ramp is formed directly in the wall, combining the support structure and threading mechanism into a single integrated component. This eliminates separate threaded inserts and reduces manufacturing complexity.
3Reliability
If the fuse insert is screwed in deeply to ensure contact, then electrical connection is reliable, but it becomes difficult to determine if sufficient engagement has been achieved
Solution Approach 1:
The recessed seat provides tactile and visual feedback to the operator during insertion. When the fuse insert reaches the recessed seat, the change in resistance and positioning provides clear feedback that sufficient engagement has been achieved, eliminating the need to estimate the required insertion depth.
Solution Approach 2:
The recessed seat creates a visible positional reference in the cavity wall. The change in depth and position of the fuse insert relative to the recessed seat provides visual indication of engagement status, making it easy to determine when proper electrical connection has been established.
4Ease of operation
If a pawl with torsion spring is used to indicate engagement, then contact establishment can be detected, but the noise is hardly audible in industrial environments
Solution Approach 1:
The acoustic feedback mechanism (pawl hitting the fuse insert to produce noise) is replaced with a mechanical positioning system using the recessed seat. The recessed seat provides direct mechanical engagement and positioning, eliminating the need for audible noise to confirm proper insertion, thereby overcoming the limitation of noise masking in industrial environments.
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
Enables rapid and certain insertion of the fuse insert, ensuring secure electrical connections and easy operation, even in noisy environments, with intuitive visual confirmation of the locked position, reducing operator effort and time.
Implementation Method 1
at least one of the grooves ending in a seat having a recess towards the opening relative to the corresponding ramp and against which is held the corresponding lug by means of an elastic member exerting a force tending to push the fuse insert along the axis of the wall
Data Source
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AI summary
The switch has a parallelepiped shaped case (1) including a lamination (6) positioned at a bottom of a cavity (10) and an upstream lamination (4) positioned between an opening and the lamination (6), where the laminations are connected to upstream and downstream terminals (2, 3), respectively. A locking unit locks an insert (20) to a fuse (21) by screwing the insert to a link at a partial rotation angle lower than or equal to 270 degree. The insert connects the laminations, when the insert is in locking position. The unit has a pin integrated to the insert and a groove (12) receiving the pin.