Drill Bit Central Pilot and Reamer Alignment
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Solution Overview
Problem
Drilling subterranean support bolts with threaded bolts is time-consuming and resource-intensive due to the need for precise drilling and the difficulty of maintaining drill bit alignment, especially when drilling at angles, as traditional drill bits tend to wander or 'walk' across the surface.
Innovation Solution
A subterranean support-bolt drilling assembly featuring a drill bit with a central pilot and a reamer member, where the drill bit and spacer combination allows for precise alignment and drilling without core formation, using polycrystalline diamond cutting elements to efficiently create boreholes of varying diameters, accommodating both threaded and lag bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional drill bits are used for drilling subterranean support bolts, then drilling operations can be performed, but the drill bit tends to wander or 'walk' across the surface, resulting in poor drilling precision and alignment difficulty
Solution Approach 1:
The drill bit incorporates a central pilot or nose portion that extends forward of the main cutting elements. This pilot portion makes initial contact with the formation surface and establishes the drilling path before the main body of the drill bit engages, preventing wandering and ensuring accurate alignment throughout the drilling operation.
2Strength
If threaded bolts are used for securing subterranean formations, then adequate support can be provided, but driving the bolts the entire length of the borehole requires significant time and energy
Solution Approach 1:
The drill bit creates a borehole with a widened portion or enlarged diameter section. This segmented hole structure allows the bolt to be installed with the threaded portion only needing to engage the narrowed section, while the widened section accommodates the unthreaded shank, reducing the length of threading required and thus reducing installation time and energy consumption.
3Adaptability or versatility
If multiple drilling operations are performed to bore a single bolt hole with varying diameters, then both threaded and lag bolts can be accommodated, but this results in wasted time and resources
Solution Approach 1:
The drill bit integrates multiple functions into a single tool: it drills the borehole, creates the widened portion for lag bolt accommodation, and establishes precise alignment all in one operation. This merging of functions eliminates the need for multiple drilling operations with different diameter bits, thereby maintaining versatility while significantly improving productivity.
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
This solution enables efficient and precise drilling of boreholes at various angles, reducing the time and energy required for subterranean support bolt installation by allowing for single-operation formation of boreholes with different diameters, preventing drill bit wandering and enhancing drilling accuracy.
Implementation Method 1
polycrystalline diamond cutting elements to efficiently create boreholes
Data Source
AI summary
A subterranean support-bolt drilling assembly has a drill bit rotatable about a central axis and including at least one cutting edge. The drilling assembly also includes a spacer coupled to a rearward end of the drill bit. A reamer member is coupled to a rearward end of the spacer, the reamer member having at least one cutting element, the at least one cutting element having a cutting edge that extends radially beyond an outer peripheral portion of the drill bit relative to the central axis. A subterranean support-bolt drill bit includes a bit body and at least one cutting element coupled to the bit body. The support-bolt drill bit has a central pilot extending from the bit body in an axially forward direction. The cutting edge of the at least one cutting element extends radially beyond the central pilot relative to a central axis of the drill bit.