Christmas Tree Plug Assembly With Locked Fuse Access
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Solution Overview
Problem
Standard electrical power cords for artificial pre-lighted Christmas trees often overload, leading to overheating and potential fires due to inadequate fuse protection, and existing designs fail to prevent accidental access to the fuse when the plug is inserted into a wall socket, posing a shock hazard.
Innovation Solution
A non-standard female polarized socket with raised side walls and a non-standard two-prong non-polarized male plug with mating grooves, along with a cover mechanism, are used to prevent inadvertent electrical connections and include a fuse holder with a releasable fuse that becomes inaccessible when the plug is inserted, ensuring safety and easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fuse is located in the plug of a standard three-wire plug that powers the tree directly, then it can provide the protection of a fuse to any seasonal lights that may be incorporated on or with the tree, but under such conditions, it is very possible for a user to contact one of the electrical conductors normally abutting the fuse and receive a potentially serious shock
Solution Approach 1:
The fuse holder is nested within the plug body, creating a hierarchical structure where the fuse is housed inside a dedicated compartment. This nesting arrangement allows the fuse to provide protection while being physically contained in a way that prevents direct contact with electrical conductors, thus resolving the contradiction between reliability and safety.
Solution Approach 2:
The patent introduces an intermediary access mechanism (such as a removable cover or sliding door) that mediates between the fuse and the user. This intermediary element allows the fuse to remain accessible for replacement while preventing direct contact with live electrical conductors, thereby eliminating the shock hazard while maintaining fuse protection functionality.
2Ease of repair
If the fuse is made accessible for easy replacement, then it can be quickly changed when needed, but it may become too easily accessible when the conducting prongs of the plug are inserted in a wall socket
Solution Approach 1:
The access mechanism to the fuse holder is designed to be dynamic rather than static. The cover can be removed or opened only when the plug is disconnected from the wall socket, providing easy access for fuse replacement during maintenance while automatically preventing access when the plug is in use. This dynamic behavior resolves the contradiction between ease of repair and safety.
Solution Approach 2:
The patent implements preliminary anti-action by designing the access mechanism to prevent access to the fuse before any potential hazard can occur. The cover remains closed and locked during normal operation, preemptively preventing any attempt to access the fuse while the plug is connected to power, thus eliminating the shock risk while allowing easy access when needed.
Data Source
AI summary
An artificial lighted tree is presented with power routed through the trunk and three-wire safety grounding. The tree comprising a fused electrical plug having improved safety features comprising: a body portion surrounding respective first ends of a first, a second and a third electrical wire, the body portion further comprising a fuse holder embedded within an upper region of the body portion, and a fuse adapted to be releasably secured within the fuse holder via releasable securing means, a live blade in communication with the first end of the first electrical wire, a neutral blade in communication with the first end of the second electrical wire, a ground pin receptacle in communication with the first end of the third electrical wire, wherein the body portion surrounds and maintains the live blade, neutral blade, and ground pin receptacle in spaced apart orientation corresponding to polarized sockets on an electrical wall outlet.