Drill Head Positioning via Sheave Sensor and Calibration

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Solution Overview

Problem

Current drill head position determination systems in blasthole drilling machines provide inaccurate position information due to slippage or jumping of the cable on the pulley system, which affects the operator's ability to perform precise drilling operations and automate functions.

Innovation Solution

A drill head position determination system that includes a sheave sensor to measure the rotational position of a sheave and proximity sensors to detect specific positions on the mast, with calibration to correct for inaccuracies caused by cable slippage, ensuring accurate drill head positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a cable-pulley system is used to move the drill head, then the drill head can be moved up and down the mast, but cable slippage or jumping occurs causing inaccurate position information

Engineering Contradiction:

Improvedrill head movementVSAvoidposition information accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

A sensor system acts as an intermediary between the mechanical cable-pulley system and the control system. The sensor detects the actual drill head position independently of cable tension or slippage, providing accurate position feedback to the controller without being affected by mechanical issues in the cable system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces reliance on mechanical cable position indication with an electronic sensing system. Instead of using the cable's mechanical state to determine position, the system uses sensors (such as encoders, potentiometers, or other position sensors) to electronically detect and report the drill head position, eliminating the accuracy problems caused by cable slippage.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If cable slippage is not accounted for, then the system is simpler, but position accuracy deteriorates

Engineering Contradiction:

Improveposition determination systemVSAvoiddrill head position accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously monitoring the actual drill head position using sensors and comparing it with the expected position based on cable movement. This feedback loop allows the controller to detect and compensate for cable slippage, maintaining position accuracy without requiring an overly complex system architecture.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The sensor system automatically detects and reports position information without requiring manual calibration or intervention. The system self-adjusts by providing real-time position data that accounts for cable slippage, eliminating the need for complex manual correction mechanisms while maintaining accuracy.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11384633B2Drill head position determination system

Publication Date: 2022.07.12 CATERPILLAR GLOBAL MINING EQUIPMENT LLC

AI summary

A drill head position determination system may include a mast, a drill head movably attached to the mast, and a drill drive assembly configured to move the drill head up and down along a length of the mast. The drill head may be configured to rotate a drill string. The drill drive assembly may include at least one sheave and a cable system wound about the at least one sheave. The drill head position determination system may further include a sheave sensor operatively coupled to the at least one sheave and configured to determine a position of the drill head based on a measured rotational position of the at least one sheave.