Switchgear Compartment Handle With Active-State Door Interlock
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current interlock systems in low, medium, and high voltage switchgear can be overridden, leading to safety risks due to the lack of integration with the handle mechanism, which does not ensure the door is fully secured before operation, and excessive force can damage the handle.
Innovation Solution
A handle for switchgear compartments that includes a body part, a hand grasping part, and a lock, configured to move from a closed to an open position, where the lock is activated by the transition of an active element from a quiescent to an active state, preventing the handle from opening the door when the element is potentially dangerous, and de-activated when safe, allowing secure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical interlock system is used in switchgear, then the safety of the device and operator is improved, but the interlock can still be overridden through excessive force or intentional action
Solution Approach 1:
The patent combines the handle mechanism with the interlock system into a single integrated unit. The handle includes a body part, hand grasping part, and lock that work together as one system, eliminating the possibility of bypassing the interlock separately from the handle operation. This merging ensures that the door cannot be opened unless the active element is in a safe state, while still allowing normal operation when safe.
Solution Approach 2:
The interlock check is performed automatically as part of the handle operation sequence. Before the door can be opened, the system must first verify that the active element is in a safe state through the lock mechanism. This preliminary safety check is built into the handle's operation, preventing override attempts before they can occur.
2Ease of operation
If the handle allows free movement to open the door, then ease of operation is improved, but the door may be opened when the active element is in a dangerous state
Solution Approach 1:
The lock mechanism serves as an intermediary between the handle and the door opening action. The lock includes a lockable element that must be in a specific position for the door to open, and this position is controlled by the state of the active element. This intermediary ensures that even if the handle is manipulated, the door cannot open unless the safety condition is met.
Solution Approach 2:
The lock mechanism prevents door opening in advance by blocking the handle's movement when the active element is in a dangerous state. The lockable element is positioned to physically prevent the handle from moving to the door-opening position, countering any attempt to open the door during unsafe conditions before such action can occur.
3Reliability
If the handle is locked to prevent door opening, then safety is improved, but the handle becomes unusable for legitimate door opening operations
Solution Approach 1:
The handle system transitions dynamically between locked and unlocked states based on the condition of the active element. When the active element is in a safe state, the lock releases and the handle becomes usable for normal door opening operations. When the active element is in a dangerous state, the lock engages and prevents door opening. This dynamic behavior ensures both safety and operational flexibility.
Solution Approach 2:
The lock mechanism receives feedback from the state of the active element and adjusts its locking status accordingly. The system continuously monitors whether the active element is in a safe or dangerous state and automatically locks or unlocks the handle based on this feedback, ensuring that the handle is only usable when it is safe to open the door.
Data Source
AI summary
A handle for a compartment of a low, medium or high voltage switchgear includes: a body part; a hand grasping part; and a lock. The handle is movable from a closed position to an open position. When the handle is in the closed position, the handle is not useable to open a door of a compartment of the switchgear. When the handle is in the open position, the handle is useable to open the door of the compartment of the switchgear. In the open position, the hand grasping part is positioned so as to be graspable by a human user. In the closed position, a transition of an active element in the compartment of the switchgear from a quiescent state to an active or potentially active state activates the lock. Activation of the lock stops the handle from moving from the closed position to the open position.