Rock Drill Feed Force Control via Load Valve

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Solution Overview

Problem

Conventional rock drilling methods rely on operator experience and are unable to quickly adapt to rapidly changing drilling conditions, leading to inefficient drilling and reduced tool life, especially when dealing with varying rock hardness and uncontrolled drill movements.

Innovation Solution

The method involves controlling feed force in relation to measured feed speed and rotation pressure, and adjusting percussion power based on feed force, using a load control valve to manage counter pressure and maintain optimal drilling conditions automatically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If operator manually adjusts drilling parameters based on experience, then drilling can be controlled in stable conditions, but the system cannot adapt quickly enough when drilling conditions change rapidly

Engineering Contradiction:
ImproveAdaptability to changing drilling conditionsVSAvoidResponse time to condition changes
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The control system continuously monitors drilling parameters (feed speed, rotation pressure, feed force) and automatically adjusts drilling conditions based on real-time feedback from sensors. This closed-loop control enables the system to detect and respond to changing rock conditions immediately, eliminating the time delay inherent in manual operator response.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The drilling system performs self-adjustment through automated control algorithms that modify feed force and percussion power based on measured drilling conditions. The system serves itself by automatically detecting condition changes and adjusting parameters without external human intervention, achieving rapid adaptation to varying rock characteristics.

Inventive Principle:
Principle #25Self-service

2Productivity

If operator monitors and controls drilling throughout entire working shift, then drilling efficiency can be maintained, but it is practically impossible to simultaneously monitor all parameters and protect tool life

Engineering Contradiction:
ImproveDrilling efficiencyVSAvoidTool life protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control system uses continuous feedback from sensors monitoring feed speed, rotation pressure, and feed force to automatically detect conditions that could lead to tool damage. The system responds by adjusting drilling parameters in real-time, simultaneously optimizing drilling efficiency and protecting tool life without requiring constant human monitoring.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces manual operator monitoring and control with an automated electronic control system that processes sensor data and adjusts drilling parameters. This substitution enables continuous, comprehensive monitoring of all drilling parameters and automatic protection of tool life, functions that are impossible for a human operator to perform consistently throughout an entire working shift.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Stability of the object's composition

If counterbalance valve closes return channel to prevent unwanted movement, then drill stability is improved, but the hydraulics easily vibrate or oscillate creating control problems

Engineering Contradiction:
ImproveDrill stabilityVSAvoidHydraulic vibration and oscillation
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The control system dynamically adjusts the counterbalance valve opening based on real-time drilling conditions and measured parameters. Rather than maintaining a fixed closed state, the valve opening is continuously modulated to provide just enough counterpressure to prevent unwanted drill movement while avoiding the hydraulic vibrations and oscillations that occur with complete closure. This dynamic control eliminates the harmful effects while maintaining stability.

Inventive Principle:
Principle #15Dynamics

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 approach allows for effective and automatic adaptation to changing drilling conditions, ensuring efficient drilling and extended tool life by dynamically adjusting drilling parameters in response to real-time measurements.

Implementation Method 1

the load control valve is connected to control counter pressure in the feed return channel when receiving a corresponding control signal

Methodology Applied
Scientific EffectHydraulic pressure control: Hydraulic Press

Implementation Method 2

there is a load control valve in the feed return channel of the feed motor (3)

Methodology Applied
Scientific EffectHydraulic motor conversion: Hydraulic Press

Implementation Method 3

controlling the percussion power in relation to the feed force so that when the feed force is decreased below a predetermined value the percussion power is decreased

Methodology Applied
Scientific EffectImpact force: Impact Force

Data Source

PatentEP2446114B1Method and apparatus for controlling rock drilling
Publication Date: 2019.01.02 SANDVIK MINING & CONSTR OY
  • EP2446114B1 patent drawingFigure 1~2
  • EP2446114B1 patent drawingFigure 3~4
  • EP2446114B1 patent drawingFigure 5a~5c

AI summary

Method and apparatus for controlling rock drilling with a percussion device (7) belonging to a rock drill (1) to deliver stress waves to rock through a tool (9) by pushing the tool against the rock by means of a feed motor (3) and rotating simultaneously the tool by means of a rotation motor, whereby the maximum feed force is determined, pressure medium is supplied to the feed motor (3) and to the rotation motor (8) and the feed force is controlled according to the drilling conditions. The feed force is controlled on the basis of the feed speed and the rotation torque. The apparatus has a load control valve which controls the feed.