Blasthole Drill Bit Retaining Assembly Centering Mechanism
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Solution Overview
Problem
Current drill bit changing systems in blasthole drill rigs face challenges in aligning and retaining drill bits due to oversized carousel pots, leading to misalignment and tilting issues, which are exacerbated by the long length of drill strings and the need for expensive multiple cylinder designs that may not consistently center the bits.
Innovation Solution
A drill bit retaining assembly featuring a ring with a guide slot and pin mechanism, coupled with a bit clamp member and actuator, allows for precise alignment and retention of drill bits through rotational movement and clamping action, ensuring the bits are centered and securely held within the carousel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If oversized carousel pots are used to allow easy drill bit insertion, then ease of operation is improved, but manufacturing precision deteriorates due to misalignment and tilting
Solution Approach 1:
A centering mechanism acts as an intermediary between the oversized carousel pot and the drill bit. This mechanism includes a centering member that contacts the drill bit and forces it into proper alignment with the drill string, mediating the conflict between easy insertion (oversized pot) and precise alignment (tight tolerances required).
Solution Approach 2:
The patent replaces complex multiple hydraulic cylinder systems with a simpler mechanical centering mechanism. Instead of using three cylinders to extend locks through the carousel pot, a single actuator moves a centering member along a guide path to achieve bit centering, reducing system complexity while maintaining alignment precision.
2Reliability
If multiple hydraulic cylinders are used to hold the drill bit in place, then reliability of bit retention is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential function of bit retention from the complex three-cylinder system and implements it through a single actuator with a centering member. By removing redundant cylinders and locks, the system achieves reliable bit retention with fewer components, reducing complexity while maintaining the core retention function.
Solution Approach 2:
The single actuator serves multiple functions: it positions the centering member to align the drill bit, holds the bit in place during operation, and releases the bit when needed. This multi-functional design replaces the specialized three-cylinder system, achieving the same reliability with reduced complexity.
3Manufacturing precision
If three cylinder locks are used to center the drill bit, then manufacturing precision may be improved, but loss of energy increases due to hydraulic fluid flow issues
Solution Approach 1:
The patent replaces the hydraulic three-cylinder system with a mechanical linkage system where a single actuator moves a centering member along a guide path. This mechanical substitution eliminates the hydraulic fluid flow issues and associated energy losses, while maintaining bit centering precision through the guide path constraints.
Data Source
AI summary
A drill bit retaining assembly includes a ring, a bit clamp member coupled to the ring, and an actuator coupled to the ring. The bit clamp member is movable via the actuator between a first position, in which the bit clamp member is configured to be engaged with a drill bit and a second position in which the bit clamp member is configured to be disengaged from the drill bit.