Junction Box Access Panel Interlock for High-Voltage Reconnection Safety
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Solution Overview
Problem
Junction box assemblies in electric motor applications do not effectively prevent the reconnection of high-voltage connectors before the access panel is reinstalled, potentially allowing the junction box to be energized while the panel is removed, posing safety risks.
Innovation Solution
A junction box assembly design featuring a pivotally mounted access panel that can be rotated between closed and open positions, with a shoulder bolt or sliding slots to ensure the high-voltage connector cannot engage when the panel is open, thereby preventing electrical power supply during access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the access panel is designed to be removable for repairs, then ease of operation is improved, but safety is worsened because the high-voltage connector can be reconnected before the panel is reinstalled
Solution Approach 1:
The access panel is designed to prevent the high-voltage connector from engaging with the housing before the panel is properly positioned. This preliminary geometric constraint ensures that the panel must be reinstalled before electrical connection can occur, eliminating the safety hazard of accidental energization during maintenance operations
Solution Approach 2:
The opening in the housing acts as an intermediary element that must be properly aligned and positioned before the high-voltage connector can engage. The panel covers this opening, and its specific geometric relationship with the housing creates a mechanical interlock that prevents connector engagement unless the panel is correctly positioned, thus mediating between the panel and connector
2Reliability
If an interlock switch is provided to prevent current flow when the panel is removed, then safety is improved, but device complexity increases
Solution Approach 1:
The patent extracts the safety function from the electrical domain (interlock switches and electrical interlocking) and relocates it to the mechanical domain through geometric constraints. The panel's physical position and the housing's opening geometry work together to prevent connector engagement, eliminating the need for additional electrical safety components
Solution Approach 2:
The invention replaces complex electrical or electronic interlock systems with a simple mechanical geometric constraint system. The relative positions and shapes of the panel, housing opening, and connector create an inherent mechanical safety feature that is more reliable and simpler than electrical interlock mechanisms
Data Source
AI summary
A junction box assembly including a housing having an opening for accessing an interior of the housing, a high-voltage connector adjacent the opening, and an access panel mounted to the housing. The access panel is movable between a first position and a second position, the first position restricting access to the opening of the housing and permitting a cooperating high-voltage connector to engage the high-voltage connector adjacent the opening and the second position permitting access to the opening of the housing and restricting a cooperating high-voltage connecter from engaging the high-voltage connector adjacent the opening.