Manhole Cover Cam Locking Mechanism for Secure Sealing

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Solution Overview

Problem

Traditional manhole covers are cumbersome to lift and maneuver due to their weight, and existing locking mechanisms are cumbersome and prone to failure under environmental conditions, making them difficult to use and maintain.

Innovation Solution

A manhole system with a rotatable locking device featuring cam locks that engage the cover's outer edge, providing a secure and watertight seal, and a plunger and spring mechanism for tactile feedback and secure positioning, allowing the cover to be easily locked and unlocked.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking mechanisms are used, then the manhole cover can be secured, but the locking device becomes cumbersome and difficult to operate

Engineering Contradiction:

Improvesecurity of manhole coverVSAvoidease of locking and unlocking

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The locking device transitions from a static padlock configuration to a dynamic cam-based mechanism that rotates between locked and unlocked positions. The cam profile converts rotational motion into clamping force, enabling easy operation while maintaining secure locking.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent replaces traditional keyed locks with a cam-based mechanical locking system. The cam profile geometry substitutes for complex key mechanisms, providing secure locking through pure mechanical action that is easier to operate and more reliable.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional locking mechanisms are used, then the manhole cover can be secured, but the locking device is prone to failure under environmental conditions

Engineering Contradiction:

Improvesecurity of manhole coverVSAvoidenvironmental degradation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The locking device parameters are optimized for environmental durability. The cam profile and locking surfaces are designed with specific geometric parameters that reduce stress concentration and improve resistance to corrosion and weathering, extending service life under severe environmental conditions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the manhole cover is made heavier, then it becomes more secure against inadvertent removal, but it becomes more difficult to lift and maneuver

Engineering Contradiction:

Improvesecurity against inadvertent removalVSAvoidease of lifting and maneuvering

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism provides a counteracting force that compensates for the weight of the manhole cover. When locked, the cam mechanism generates sufficient clamping force to counteract the cover's weight and prevent inadvertent removal, allowing lighter cover materials to be used without sacrificing security.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The locking device is pre-configured in a locked state by default, with the cam profile designed to engage automatically when the cover is placed on the frame. This preliminary locking action eliminates the need for manual securing operations and ensures security before the cover is subjected to vehicle traffic or other external forces.

Inventive Principle:

Principle #10Preliminary action

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 system ensures secure and easy operation of manhole covers, preventing unauthorized removal and maintaining a watertight seal, even under severe environmental conditions, while providing tactile feedback for user convenience.

Implementation Method 1

the locking device includes a plurality of cam locks that include an angled or cammed surface... the locks are configured are cammed to increasingly clamp down the cover with increasing rotation from 'unlocked' position to 'locked' position

Methodology Applied

Scientific EffectCam mechanism: Cam

Implementation Method 2

The lock may be removably secured within the seat by a plunger and spring. The plunger and spring may be configured to provide a bias or tactile response when the lock is positioned in either the 'locked' or 'unlocked' positions

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentUS7726903B2Manhole system

Publication Date: 2010.06.01 EJ USA INC

AI summary

A manhole system that includes a manhole cover and a frame with at least one locking device for maintaining the manhole cover in place on the frame. The locking device is selectively movable between locked and unlocked positions to selectively engage the cover to hold the cover in place on the frame. The locking device may be rotatable between “locked” and “unlocked” positions about an axis perpendicular to the plane of the cover. The locking device may includes a plurality of cam locks that engage the outer circumferential edge of the cover and are configured to increasingly clamp down the cover against the frame with increasing rotation from “unlocked” position to “locked” position. A plurality of locks can be arranged around frame to engage the cover at different locations.