Composite Manhole Cover Frame with Anchoring Ribs
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Solution Overview
Problem
Manhole cover frames made of cast iron corrode, leading to structural deterioration and visual damage, and existing corrosion-protected frames fail to withstand traffic stresses, resulting in high maintenance costs and safety concerns.
Innovation Solution
A frame comprising a plastic upper part with anchoring ribs and a concrete lower part, where the plastic parts are protected from warping and corrosion, and the concrete provides structural support, with sealing sections to prevent cement laitance contamination and enhanced adhesion to the concrete lower part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cast iron frames are used, then structural strength is achieved, but corrosion resistance deteriorates
Solution Approach 1:
The frame combines plastic (upper part) and concrete (lower part) materials to create a composite structure that leverages the corrosion resistance of plastic and the structural strength of concrete, resolving the contradiction between strength and corrosion resistance
2Reliability
If corrosion-protected cast iron frames with coatings are used, then corrosion resistance is improved, but the coatings are worn away by traffic stresses
Solution Approach 1:
The invention replaces the vulnerable coating layer with an intrinsic material property solution - using plastic that inherently resists corrosion without requiring protective coatings that can be worn away, eliminating the coating durability problem
3Reliability
If the plastic upper part is made fully accessible from outside, then corrosion protection is improved, but warping resistance deteriorates
Solution Approach 1:
The composite structure of plastic upper part and concrete lower part creates a stabilized assembly where the concrete provides rigidity and warping resistance to the plastic component, allowing the plastic to be fully exposed without compromising structural stability
4Strength
If anchoring ribs are added to improve adhesion, then connection strength is improved, but device complexity increases
Solution Approach 1:
The anchoring ribs are integrated directly into the plastic upper part during molding, combining the connection function with the main structural component rather than adding separate fastening elements, thus improving adhesion without significantly increasing overall complexity
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
Ensures high durability and resistance to corrosion, reduces maintenance costs, and maintains structural integrity under traffic loads while preventing visual damage from rust contamination.
Implementation Method 1
These seals are pressed (under deformation) so firmly onto the concrete mold that the seam between the concrete mold and the plastic part is liquid-tight when concreting is carried out
Implementation Method 2
a plastic upper part with molded and downwardly projecting anchoring ribs... The anchoring ribs, which project essentially radially outwards, are designed to diverge from one another at least in pairs in the direction of the outside of the frame. This results in improved adhesion of the upper part to the lower part
Data Source
Figure 1~4
Figure 5~6
Figure 7~10
AI summary
Frames for receiving a manhole cover are known. It is proposed to provide a plastic upper part (10) with molded-on, downward-projecting anchoring ribs and with a downward-projecting outer skirt (12) and a downward-projecting inner skirt (13), which form at least part of an outer and an inner circumference of the frame, respectively. A concrete lower part (30) is provided, which is cast onto the upper part (10), including the anchoring ribs and leaving the outer surfaces of the outer skirt (12) and the inner skirt (13) exposed.