Switching Device Locking Mechanism Direct Shaft Engagement
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Solution Overview
Problem
Existing switching devices for low and medium voltage electric circuits lack reliable and accessible locking mechanisms, particularly in hard-to-reach locations, making it difficult to ensure safe operation and prevent accidental re-closure.
Innovation Solution
A switching device with a locking mechanism that directly acts on the main rotating shaft, featuring a movable element and blocking means accessible from the outside, which can be manually locked using padlocks or similar, and includes signaling devices to indicate its status and prevent re-closure attempts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking devices are operatively connected to the kinematic chain to indirectly act on the rotating shaft, then the locking function is achieved, but the locking reliability is insufficient due to the indirect action through multiple components
Solution Approach 1:
The locking device is extracted from the indirect kinematic chain connection and directly coupled to the rotating shaft. The blocking element engages directly with the shaft surface, eliminating intermediate components and providing direct mechanical constraint, which significantly improves locking reliability while simplifying the overall structure.
Solution Approach 2:
A blocking element is introduced as a direct intermediary between the locking device and the rotating shaft. This blocking element directly contacts the shaft surface and prevents rotation, creating a simple yet reliable locking path without complex kinematic chains.
2Ease of operation
If locking status is only visually signalled through component positioning, then the locking device structure is simple, but the accessibility for status checking becomes problematic when devices are located in hard-to-reach positions
Solution Approach 1:
A feedback mechanism is implemented where the blocking element's position relative to the rotating shaft provides direct visual indication of locking status. When the shaft is locked, the blocking element assumes a specific position that can be observed through an opening in the housing, providing immediate feedback without requiring physical inspection of internal components.
Solution Approach 2:
The visual indication system replaces complex mechanical inspection requirements with a simplified optical observation through an opening. The blocking element's position is designed to be visible from outside the housing, substituting the need for physical access to internal mechanisms with external visual monitoring.
3Ease of operation
If the main rotating shaft ends are made accessible from the outside through openings, then the locking device can directly act on the shaft, but the protection of the shaft from external contaminants may be compromised
Solution Approach 1:
The opening in the housing is designed as a nested structure where the blocking element moves within a constrained path that is partially enclosed. The opening allows access for the blocking element to engage the shaft while the housing structure provides partial protection, creating a nested arrangement that balances accessibility with contamination protection.
Solution Approach 2:
The housing opening is designed with local quality variations - it provides access only where needed for the blocking element to engage the shaft, while other areas of the housing remain sealed. The opening dimensions and positioning are optimized to provide minimum necessary access while maximizing protection, creating a localized access point rather than a general opening.
Data Source
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AI summary
A switching device for an electric circuit, comprising: - at least one contact movable between a closed position in which it is coupled to a corresponding fixed contact and an open position in which it is spaced away from said corresponding fixed contact; - a main shaft suitable for rotating about an axis and operatively connected to said at least one movable contact so as to cause with its rotation the movement of said at least one movable contact between the open and closed positions. The switching device comprises a locking device which has one or more parts coupled to and which is configured for directly acting on the main rotating shaft and locking said at least one movable contact in the open position.