Sliding Lockout Key for Hazardous Area Receptacles
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Solution Overview
Problem
Conventional hazardous location receptacles allow the use of standard plugs, which can lead to sparking and explosions due to their smaller diameter and lack of locking grooves, posing a safety risk in hazardous environments.
Innovation Solution
The receptacle design incorporates a sliding key portion that prevents standard plugs from being used by requiring a larger diameter to depress and rotate the locking plate, ensuring only hazardous area plugs can establish an electrical connection, with a spring mechanism to facilitate the sliding key's movement and engagement with the receptacle housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional receptacles use fixed key portions that lock the plug in place, then the plug is securely locked and prevents accidental disengagement, but standard plugs can also be inserted and locked, creating a safety hazard
Solution Approach 1:
The key portion is designed with a ledge that provides different engagement characteristics: it locks hazardous location plugs securely while preventing standard plugs from being locked due to their smaller diameter. The ledge creates a local geometric constraint that discriminates between plug types.
Solution Approach 2:
Instead of using fixed key portions that passively lock any plug, the invention uses a movable key portion that actively prevents locking unless the correct plug type is inserted. The locking function is inverted from passive to active, requiring positive engagement of the ledge by the plug housing.
2Ease of operation
If the receptacle allows easy insertion of plugs, then ease of operation is improved, but standard plugs can be easily inserted and pulled out, creating safety risks
Solution Approach 1:
The movable key portion is positioned in advance to block the locking path. When a plug is inserted, the key portion must first be moved out of the way, allowing the plug to engage the ledge. This preliminary blocking action ensures that only plugs with sufficient diameter can complete the engagement sequence.
3Object-affected harmful factors
If the key portion is made movable to prevent standard plug locking, then safety is improved, but the device complexity increases due to the spring mechanism
Solution Approach 1:
The spring automatically moves the key portion back to its blocking position after a plug is inserted and locked. The system serves itself by using the insertion force to compress the spring and the spring's rebound to reset the key portion, eliminating the need for manual resetting or complex control mechanisms.
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
This design effectively prevents the use of standard plugs, minimizing the risk of sparking and ensuring safe operation in hazardous locations by ensuring only compatible plugs can complete the electrical circuit and lock into place.
Implementation Method 1
The spring facilitates movement of the sliding key portion when a hazardous area plug is inserted into the receptacle. Upon insertion of the plug into the receptacle, the spring compresses and the ledge of the sliding key shifts into a groove in the receptacle housing and allows the locking plate to then rotate.
Data Source
AI summary
Receptacles configured to securely mate with hazardous area plugs are provided. The receptacles include a housing, a locking plate, and a sliding lockout key. The sliding lockout key prevents the locking plate from rotating when the receptacle and plug are disconnected or when a standard plug is inserted into the receptacle. When the proper plug is inserted into the receptacle, the sliding key portion is depressed and allows rotation of the locking plate. Upon rotation, pins from the plug contact internal pins of the receptacle and make an electrical connection.