Manhole Cover Frame Removal Saw with Segmented Cutting
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Solution Overview
Problem
Conventional methods for removing manhole cover frames from pavement are laborious, time-consuming, and damaging to the pavement, requiring jackhammers to break up the surrounding material, which leads to cracks and subsequent degradation.
Innovation Solution
A novel system using a ring-shaped base with anchoring fasteners, a saw mounting framework, and interchangeable saw blades to cut a horizontal radial groove and a vertical circular groove around the manhole cover frame, allowing the frame to be lifted out without damaging the pavement, and subsequently replaced with minimal disruption to the road foundation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a jackhammer is used to break up pavement surrounding the manhole cover frame, then the frame can be removed from the pavement, but the pavement is damaged with cracks that lead to subsequent degradation
Solution Approach 1:
The removal process is segmented into two distinct cutting phases: first a horizontal radial groove is cut beneath the frame, then a vertical circular groove is cut around the periphery. This segmentation allows the frame to be freed without impacting the surrounding pavement structure, eliminating the harmful effects of jackhammering while maintaining ease of removal.
Solution Approach 2:
The invention extracts only the necessary portion of pavement material (a small cylindrical section beneath and around the frame) by making precise radial and circular cuts. This extraction approach removes the frame with minimal pavement loss, preserving the integrity of the surrounding road foundation unlike the destructive jackhammer method.
2Ease of operation
If a jackhammer is used to break up pavement about the periphery of the manhole cover frame, then the frame can be freed, but the work is slow and backbreaking
Solution Approach 1:
The invention replaces the impact-based mechanical system of jackhammering with a cutting-based mechanical system using saw blades. The saw blades efficiently slice through pavement and the frame material, significantly reducing removal time and physical effort compared to the slow, laborious process of breaking up pavement with a jackhammer.
Solution Approach 2:
The horizontal radial groove is cut beneath the frame before the vertical circular groove is cut around the periphery. This preliminary action creates a clean separation plane that facilitates rapid frame removal, improving productivity by preparing the release path in advance rather than breaking material away during removal.
3Ease of operation
If jackhammering is used to remove the manhole cover frame, then the frame can be removed, but the foundation is damaged requiring over excavation and rebuilding
Solution Approach 1:
The invention extracts the frame with minimal pavement removal by making precise cuts that free only the frame and a small amount of surrounding material. This preserves the road foundation, eliminating the need for time-consuming over excavation and rebuilding operations that are required when jackhammering damages the foundation.
Solution Approach 2:
By cutting the horizontal radial groove beneath the frame first, the invention creates a clean release plane that allows the frame to be removed without disturbing the foundation. This preliminary preparation prevents foundation damage, avoiding the subsequent time loss associated with repairing damaged roadbeds.
4Ease of operation
If conventional removal methods are used, then the frame can be removed, but labor and expense increase due to over excavation and rebuilding
Solution Approach 1:
The cutting process is segmented into efficient radial and circular passes that remove only the necessary material. This segmented approach reduces both labor requirements and material waste, making the operation more cost-effective compared to the expensive over excavation and rebuilding required by conventional jackhammering methods.
Solution Approach 2:
The invention replaces the expensive, labor-intensive jackhammering process with a more efficient cutting system using saw blades. This substitution reduces both direct labor costs and indirect costs associated with pavement repair, improving overall cost effectiveness while maintaining ease of frame removal.
Data Source
AI summary
A manhole cover frame removal apparatus has a ring-shaped base with a circular track thereon and a saw mounting framework disposed atop the base. Rollers allow the saw mounting framework to advance in rotation about aligned vertical axes of the frame and the base. A saw mounting arm is joined to the framework and may be raised and lowered and locked in the raised position. A saw carriage is mounted on the saw arm for reciprocal movement toward and away from a saw arm hinge axis. A single saw motor is mounted on the carriage and can be immobilized at selected angles. Separate horizontal-cut and vertical-cut saw blades are alternatively and interchangeably attached to the saw blade rotor.