Boring Machine with Undercut Assembly for Paved Slab Repair
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Solution Overview
Problem
Existing equipment for repairing potholes in concrete slabs is inefficient, resulting in shallow saw cuts, excessive dust and noise, and patches that are prone to dislodging under traffic, requiring multiple skilled laborers and multiple equipment setups.
Innovation Solution
A boring machine with a milling assembly and coring bit that creates a smooth bore and an undercut to secure patches, combined with a vacuum system to manage dust and debris, and pressurized air for cleaning and drying.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a concrete saw is used to cut a square hole around a pothole, then the hole can be formed, but the saw cuts are shallow at the corners and deeper toward the middle, requiring additional chipping work
Solution Approach 1:
The cutting operation is divided into two distinct stages: first, a coring bit creates a precise circular guide hole at the pothole location; second, a milling assembly with multiple milling bits expands the hole to the full required diameter and depth. This segmentation allows each component to perform its specialized function optimally, avoiding the uniformity problems of square saw cuts.
Solution Approach 2:
The manual or mechanical saw cutting process is replaced with a rotating coring bit and milling assembly system. The coring bit uses a diamond-impregnated or abrasive mechanism to bore a precise circular hole, which is then expanded by the milling assembly. This substitution eliminates the geometric limitations of square saw cuts and provides uniform depth control.
2Productivity
If a jack hammer is used to chip away concrete within the saw cuts, then the concrete can be removed, but considerable dust and noise are generated that need to be abated
Solution Approach 1:
The jack hammer impact mechanism is replaced with a rotating coring bit and milling assembly that uses abrasion and cutting to remove concrete. This substitution maintains high productivity while dramatically reducing dust and noise generation, as the controlled rotational cutting process is much quieter and produces less airborne particulate matter compared to impact fracturing.
Solution Approach 2:
A vacuum system with a vacuum pump and hose is introduced as an intermediary to capture dust and debris at the source during the coring and milling operations. This intermediary mechanism prevents dust from becoming airborne and can collect debris for proper disposal, eliminating the harmful dust and noise problems associated with jack hammering.
3Productivity
If square patches are used to repair potholes, then the repair can be completed, but the patches are prone to pop loose quickly under traffic
Solution Approach 1:
Instead of creating a square hole with sharp corners that concentrate stress, the invention creates a circular hole with smooth, rounded edges through the coring bit operation. This inversion of the geometric form eliminates stress concentration points, allowing the patch to distribute traffic loads more evenly and resist popping loose under vehicle traffic.
Solution Approach 2:
The coring bit creates a circular hole with uniformly smooth walls and rounded corners, providing consistent local quality around the entire perimeter. This uniform geometry ensures that the patch material bonds evenly to the surrounding concrete at all points, preventing localized failure points that would occur with the sharp corners of square holes.
4Manufacturing precision
If multiple skilled laborers and multiple equipment setups are used for repair, then the hole can be properly formed and cleaned, but the process becomes time-consuming
Solution Approach 1:
The coring bit operation and the hole formation process are merged into a single integrated operation. The coring bit simultaneously creates the precise circular guide hole and prepares the location for the subsequent milling expansion, eliminating the need for separate positioning and cutting operations. This merging reduces the number of laborers and equipment setups required while maintaining high precision.
Solution Approach 2:
The coring bit serves multiple functions: it creates the initial circular guide hole, defines the precise location and depth of the pothole repair, and provides a smooth-walled template for the subsequent milling expansion. This multi-functionality eliminates the need for separate positioning devices, guide holes, and depth control mechanisms, reducing both time and labor requirements while maintaining precision.
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 solution expedites the repair process, reduces dust and noise, and enhances patch stability by creating a secure undercut for the patch, improving road comfort and reducing the need for multiple laborers and equipment.
Implementation Method 1
A vacuum is drawn through the vacuum conduit to suck dust and debris from the milling and boring operation out from the hole
Implementation Method 2
Water nozzles may also be mounted on the milling assembly or at other locations within to boring machine and connected to a water supply to direct water across the milling bits to lubricate and cool the milling bits and the coring bit
Implementation Method 3
Water nozzles may also be mounted on the milling assembly or at other locations within to boring machine and connected to a water supply to direct water across the milling bits to lubricate and cool the milling bits and the coring bit
Implementation Method 4
Pressurized air may also be selective directed into the hole through the boring machine to assist in cleaning and drying the hole
Data Source
AI summary
A machine for boring holes into a slab includes a plurality of milling bits mounted on a distal end of a rotatable carrier and a coring bit slidably connected to the carrier such that the coring bit rotates with the rotating carrier and is slidable axially relative to the carrier. The coring bit cuts a relatively smooth bore into the solid medium whereas the milling bits create a bore with a relatively rough finish. An actuator engages the coring bit to adjust the depth of cut of the coring bit relative to the milling assembly depending on the desired finish of the hole to be bored. An undercut assembly is mounted on the carrier and selectively operable to form an undercut in the slab at the bottom of the hole so that a cured patch of material poured into the hole is restrained from working loose from the hole.