Spring-Loaded Plug Locking Mechanism for Debris Protection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing locking and unlocking devices for manhole covers using a key are prone to debris accumulation, which can obstruct the key's operation and lead to difficulties in pivoting the bolt from the locking to the unlocking position, and the use of removable plugs can result in misplacement or theft.

Innovation Solution

A locking mechanism where the rotor extends perpendicularly under a cover with a closure plug supported by a return spring, and the key's insertion causes the plug to move against the spring's bias, engaging with the arm to rotate the rotor, allowing the bolt to pivot between captive and disengaged positions, with a cylindrical closure cap and tenons for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the through opening of the buffer is left open for key access, then the lock can be operated, but debris can enter and accumulate, obstructing key operation

Engineering Contradiction:
Improvekey accessVSAvoiddebris accumulation
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The opening is segmented into two functional zones: an upper through-opening for key insertion and a lower operational chamber. The closure plug acts as a movable separator that divides the opening when closed, allowing key access while blocking debris from entering the internal components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The closure plug serves as an intermediary element that can be temporarily moved aside during key insertion and then returned to its closed position. This mediator allows controlled access while maintaining protection, enabling the system to switch between open and closed states as needed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a removable plug is used to close the opening, then debris is blocked, but the plug can be misplaced or stolen

Engineering Contradiction:
Improvedebris blockingVSAvoidplug security
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The closure plug is merged with the lock mechanism through the rotor connection. The plug and lock operate as an integrated system where the plug's position is controlled by the rotor's rotation, eliminating the possibility of the plug being removed or misplaced independently.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The closure plug transitions from a static removable component to a dynamic element that automatically moves between open and closed positions based on the lock's state. The spring-loaded mechanism provides automatic return to the closed position, ensuring continuous protection without manual intervention.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If the closure plug is spring-loaded to automatically return to closed position, then the opening is hermetically sealed, but the key must displace the plug to access the lock

Engineering Contradiction:
Improvehermetic sealingVSAvoidkey insertion mechanism
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The key performs multiple functions: it inserts through the opening, displaces the closure plug, engages with the rotor, and operates the lock mechanism. This multi-functional design eliminates the need for separate mechanisms for plug displacement and lock operation, simplifying the overall system despite the spring-loaded plug.

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 mechanism effectively prevents debris from entering the opening, ensures the key remains captive for unlocking and re-locking, and provides a secure, hermetic closure without the risk of the plug being misplaced or stolen.

Implementation Method 1

a closure plug (18) support under the cover in its closed position in the emerging opening by a return spring (22)

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP2565353B1Locking and unlocking device using a key of a buffer on a frame with integral cap for closing an opening of the buffer for inserting the key
Publication Date: 2019.07.24 EJ EMEA
  • EP2565353B1 patent drawingFigure 1
  • EP2565353B1 patent drawingFigure 2
  • EP2565353B1 patent drawingFigure 3

AI summary

The mechanism has a lock (6) whose rotor (11) is perpendicularly extended under a plug (1). An emerging opening (4) of the plug is coaxial with an end (11b) of the rotor. The rotor end is engaged with a coaxial casing (8) of a longitudinal arm (7) of a key (3). The opening is sealed by a stopper (18) return in support under the plug to its closing position of the opening by a return spring (22). The key causes movement of the stopper against back pulling force of the spring along the rotor when the key is introduced into the opening.