Coaxial GFCI Latching Layout for Shallow Receptacle Space

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Solution Overview

Problem

Conventional circuit interrupting devices, such as GFCIs and circuit breakers, require substantial space due to their latching mechanisms, limiting the compactness of electrical receptacles and reducing available space for other features.

Innovation Solution

The design incorporates a compact latching mechanism with a symmetrical placement of sensing cores and a vertical solenoid, allowing for a more compact electrical outlet receptacle by optimizing the use of space and enabling efficient tripping and resetting processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional latching mechanisms are used in GFCI devices, then the device can maintain contacts in a closed position, but the device occupies substantial physical space within the receptacle housing

Engineering Contradiction:
Improvecontact holding capabilityVSAvoidreceptacle housing space
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent integrates the latching mechanism components within the existing receptacle housing structure, nesting the latching mechanism inside the housing rather than requiring external space. The actuator arm, spring, and cam surfaces are arranged to fit within the confined space of the receptacle, allowing the latching function to be embedded within the overall device structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a conventional horizontal latching arrangement to a vertical latching mechanism. The actuator arm moves vertically within the housing, and the cam surface is oriented vertically, allowing the latching action to occur in the vertical dimension rather than horizontally. This dimensional change enables more efficient space utilization within the receptacle housing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If sensing cores are placed symmetrically across the receptacle, then the design achieves compactness and space efficiency, but the manufacturing complexity increases

Engineering Contradiction:
Improvereceptacle housing spaceVSAvoidsensing core placement precision
Core Design Contradiction:
Volume of stationary objectVSEase of manufacture

Solution Approach 1:

The patent employs asymmetric placement of the sensing cores relative to the receptacle housing, with one sensing core positioned closer to the front than the other. This asymmetric arrangement simplifies the manufacturing process by reducing the precision requirements for core placement while still achieving the desired compact design and functional performance.

Inventive Principle:
Principle #4Asymmetry

3Area of stationary object

If a vertical solenoid configuration is used, then the device achieves a more compact footprint, but the latching mechanism complexity increases

Engineering Contradiction:
Improvereceptacle footprintVSAvoidlatching mechanism structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent designs the actuator arm to serve multiple functions: it acts as both the latching element that engages with the cam surface and the releasing element that can be actuated by the reset button. The spring provides both the latching force and the resetting force. This multi-functionality reduces the number of separate components needed, simplifying the overall mechanism despite the vertical configuration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The solution achieves a more compact electrical outlet receptacle design that maintains functionality while providing additional space for other features, enhancing usability and flexibility in electrical installations.

Implementation Method 1

a solenoid having a central axis perpendicular to the first plane

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

The slide mechanism includes a cam surface to transform a downward force to a translational force applied to the coupled lifting shelf

Methodology Applied
Scientific EffectCam mechanism: Cam

Data Source

PatentEP4407815B1Shallow electrical protection device (GFCI, afci, and afci/GFCI) system and method
Publication Date: 2025.10.15 HUBBELL INC
  • EP4407815B1 patent drawingFigure 1
  • EP4407815B1 patent drawingFigure 2
  • EP4407815B1 patent drawingFigure 3

AI summary

A resettable switching apparatus, useful in a GFCI receptacle, has a space-efficient coaxial configuration in which a mechanical latching arrangement for resetting (i.e., closing) main switch contacts 48A,48B is disposed inside the trip solenoid 60. A movable carriage 62 for the main contacts 48A, 48B spans one end of the solenoid 60 and has a latching portion in the solenoid 60 that engages the inner end of a reset plunger 66 in two sequential states (i.e., unlatched and latched). The mechanical latching arrangement comprises a cam surface 72 coupled to a lifting plate 74, which is connected to the carriage 62 of the GFCI receptacle. The cam surface 72 is responsible for translating a downward movement to a translational movement to engage the carriage 62 to the rest plunger 66.