Manhole Cover Hinge with Pneumatic Assistance

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Solution Overview

Problem

Existing hinge devices for tilting manhole covers are complex and unsuitable for easy maneuvering, often leading to jamming issues when trying to open or close thick covers that fit into the frame's thickness.

Innovation Solution

A simplified hinge device with two pairs of connecting rods and assistance gas cylinders that exert thrust forces near the articulation axes, allowing for easy tilting and opening/closing of the cover without significant effort, featuring a deformable quadrilateral structure and elastic damping for smooth operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional hinge device with multiple connecting rods and springs is used, then the cover can be articulated between closed and open positions, but the structure becomes extremely complex and difficult to operate

Engineering Contradiction:
Improvearticulation reliabilityVSAvoidhinge structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The hinge device is segmented into two independent pairs of connecting rods, each pair working autonomously to articulate the cover. This segmentation simplifies the overall structure by dividing the complex multi-rod mechanism into manageable, identical units that can be easily manufactured and maintained.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a complex multi-link mechanism that requires multiple articulation points, the invention inverts the approach by using a simpler two-rod pair system where the rods are directly articulated to the cover and frame, eliminating the need for intermediate connection points and reducing overall structural complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If coil springs are used to raise the hatch after unlocking, then the hatch can be lifted a few centimeters, but thick hatches fitting into the frame thickness cannot pivot without jamming

Engineering Contradiction:
Improvehatch lifting easeVSAvoidpivot movement reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention replaces mechanical coil springs with pneumatic or hydraulic thrust members (cylinders) that provide controlled linear thrust force. This allows the cover to be raised smoothly without the jerky motion and space constraints of spring-based systems, enabling thick covers to pivot freely without jamming while maintaining ease of operation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The thrust member acts as an intermediary between the locking mechanism and the cover, providing a controlled force transmission that lifts the cover gradually. This intermediary mechanism eliminates the direct spring-to-cover connection that causes jamming, allowing the cover to pivot smoothly throughout its entire range of motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Shape

If the cover fits into the thickness of the frame sides, then a flush closed position is achieved, but the cover jams when trying to pivot after unlocking

Engineering Contradiction:
Improvecover flush fitVSAvoidcover pivoting ease
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The invention replaces the traditional mechanical hinge system with a parallel rod mechanism that substitutes rotational pivoting with a combination of linear and angular motion. The two pairs of parallel rods guide the cover through its motion path, allowing it to maintain a flush fit while eliminating the jamming issue through a different mechanical approach.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The hinge device incorporates dynamic motion characteristics where the connecting rods change their relative positions and angles during operation. This dynamic configuration allows the cover to transition smoothly from the flush closed position to the open position, adapting the mechanism's geometry to prevent jamming while maintaining the desired shape.

Inventive Principle:
Principle #15Dynamics

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

Enables effortless operation of manhole covers by reducing the effort required for opening and closing, preventing jamming and ensuring smooth movement between closed and open positions while maintaining a simple structure.

Implementation Method 1

an elastic element, such as a helical compression spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a helical compression spring mounted concentrically around the rod

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

two lateral gas cylinders each connected articulated between the frame and the buffer

Methodology Applied
Scientific EffectPneumatics:

Data Source

PatentEP2078116B1Device for hinging a lid or cover to a frame, such as a manhole
Publication Date: 2012.02.01 NORINCO SA
  • EP2078116B1 patent drawingFigure 1~2
  • EP2078116B1 patent drawingFigure 3~4
  • EP2078116B1 patent drawingFigure 5

AI summary

The present invention relates to a device for hinging a lid or cover to a frame, such as a manhole. The device is characterized in that it comprises two lateral pairs of links (6, 7) connecting the lid (2) to the frame (3) and allowing, when a lifting force is applied to the lid (2) occupying its lowered closed position, a couple to be applied to the lid (2) causing the lid (2) to come out of the frame (3) and causing the lid (2) to pivot about itself to its raised position in which it is held by the links (6, 7). The invention is applicable to roads.