End Cap Switch Assembly for Tubular Light Source Safety
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Solution Overview
Problem
The installation of retrofitted LED tubular light sources poses a safety hazard due to the risk of electrical shock from exposed live end caps, as existing safety switches can be unintentionally engaged during installation, providing a false sense of security and not ensuring complete safety.
Innovation Solution
An end cap with a switch assembly that automatically closes the electrical circuit only when the connector pins are out of reach, featuring a rotatable switch element with screw threads that forms a conductive path between the socket and the tubular light source during installation, ensuring the pins are not live until fully installed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a push-in safety switch is introduced in the end cap, then safety during installation is improved, but the switch may be unintentionally engaged during installation, providing a false sense of security
Solution Approach 1:
The patent applies preliminary action by designing the switch element to be automatically actuated during the insertion process itself. The switch element is positioned and dimensioned so that it is pushed into the actuated position by the insertion movement of the end cap into the fixture, ensuring the electrical connection is established before the installer can touch the connector pins, eliminating the need for separate manual switching action
Solution Approach 2:
The switch element serves as an intermediary mechanism between the mechanical insertion action and the electrical connection. It translates the physical act of inserting the end cap into the fixture into the electrical switching action that closes the circuit, ensuring that the electrical connection can only be made through the proper installation sequence
2Reliability
If the electrical circuit is closed automatically during installation, then installer safety is improved, but the device complexity increases due to the switch assembly
Solution Approach 1:
The patent merges the safety switching function with the existing end cap structure. The switch element is integrated into the end cap housing, and the connector pins are arranged to work in conjunction with the switch element. This combination eliminates the need for separate safety switch devices while still providing the required safety function
Solution Approach 2:
The end cap structure is designed to perform multiple functions: it provides mechanical support for the LED tubular light source, provides the electrical connection through connector pins, and simultaneously acts as the actuating mechanism for the safety switch. The switch element itself serves dual purposes as both a safety device and a connection component
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
Significantly reduces the risk of electrical shock during installation by ensuring the electrical connection is only made after the end cap is securely mounted, enhancing installer safety and preventing accidental engagement of the safety mechanism.
Implementation Method 1
the switch element comprises an embedded conductive element configured to form a conductive path between the connector pins and the tubular light source through an axial rotation of the switch element
Data Source
Figure 1a~1b
Figure 2a~3b
Figure 4a~4b
AI summary
An end cap (104) for a tubular light source (102), the tubular light source (102) being configured to be arranged in a lighting fixture (106) comprising at least one socket (108), wherein the end cap (104) comprises a housing (202), two connector pins (112) at least partly arranged on an outside of the housing (202) and adapted to fit in the socket, and a switch assembly comprising a switch element (110) arranged in between the two connector pins (112) and at least partly protruding from an opening in the housing (202), wherein a first side of the switch element (110) is adapted to fit into a slot in a socket (108) and wherein the switch assembly is configured to form a conductive path between the socket (108) and the tubular light source (102) through an axial rotation of the switch element (110) in relation to the housing (202) as the tubular light source (102) is rotatably mounted in the fixture (106).