Socket With Retractable Collar for Compact Mains Plug Design

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Solution Overview

Problem

Conventional sockets for mains plugs require a large overall height for protection against accidental contact and grounding, leading to space inefficiencies in flush mounting, surface mounting, and storage, especially when installed in extension cords or socket strips.

Innovation Solution

A socket design featuring a movably mounted collar that can retract when not in use, coupled with a coupling mechanism for the cover, allowing the socket to reduce its overall height without compromising safety, and incorporating sliding contacts for grounding to eliminate the need for cables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid collar is arranged around the base to provide protection against accidental contact and grounding, then safety is improved, but the overall height of the socket increases

Engineering Contradiction:
Improveprotection against accidental contactVSAvoidoverall height of the socket
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The collar is made movable rather than fixed, allowing it to transition between retracted and extended positions. This dynamic design enables the collar to provide protection only when needed (during plug insertion), while minimizing the socket's overall height during normal operation, thus resolving the contradiction between safety and compact dimensions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the collar is extended to ensure protection during plug insertion, then safety is improved, but the socket occupies more space during storage and transport

Engineering Contradiction:
Improvegrounding protectionVSAvoidspace occupied during storage
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The collar can be retracted into a compact position for storage and transport, significantly reducing the volume occupied by the socket. When needed during plug insertion, the collar extends to provide grounding protection, thus resolving the contradiction between safety functionality and storage efficiency.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the collar height is increased to match the length of contact pins for protection, then safety is improved, but the socket requires deeper wall cutouts for flush mounting

Engineering Contradiction:
Improveprotection against electric shockVSAvoiddepth of wall cutout required
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The collar extends only during the brief moment when a plug is being inserted, providing protection without requiring a permanently deep wall cutout. The retracted collar allows for shallow mounting, thus resolving the contradiction between safety protection and installation requirements.

Inventive Principle:
Principle #15Dynamics

4Reliability

If protective contact springs are connected via cable to ground connection, then grounding reliability is improved, but manufacturing cost increases and fault susceptibility increases

Engineering Contradiction:
Improvegrounding connectionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The protective contact springs are integrated directly with the base structure, eliminating the need for separate cable connections. This merging of components reduces manufacturing complexity and cost while improving reliability by removing potential failure points associated with cable connections.

Inventive Principle:
Principle #5Merging (Combining)

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 design achieves a compact form factor, reducing space usage by up to half, enabling new installation options and reducing storage and transport costs, while maintaining operational safety and minimizing damage susceptibility.

Implementation Method 1

it is particularly favorable if the protective contact spring is electrically connected to a ground connection of the base via a sliding contact, in order to avoid a cable connection that is expensive to manufacture and prone to faults

Methodology Applied
Scientific EffectSliding contact:

Data Source

PatentEP3830908B1Socket
Publication Date: 2022.04.20 MASS TECH INNOVATIONS GMBH
  • EP3830908B1 patent drawingFigure 1a~1b
  • EP3830908B1 patent drawingFigure 2a~2b
  • EP3830908B1 patent drawingFigure 3a~3b

AI summary

Socket (1) for a mains plug with at least two contact pins, comprising: a base (2) which, on an outer face (3), has at least two female connectors (4) for receiving in each case one contact pin; a cover (10) which is mounted on the base (2) such that it can move between a closed position, in which it closes the female connectors (4), and an open position, in which it exposes the female connectors (4); a collar (8) which is mounted on the base (2) such that it can move between a retracted position, in which it lies substantially flush with said outer face (3), and an extended position, in which it projects from the outer face (3), surrounding the latter in the manner of a collar; and a coupling mechanism which couples the cover (10) to the collar (8) and is designed such that the cover is in the closed position when the collar (8) is retracted and is in the open position when the collar (8) is extended.