Cable Rock Bolt Installation Machine with Pre-Anchoring

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Solution Overview

Problem

Current methods for installing cable rock bolts in underground mining are inefficient, requiring a two-stage process with primary solid bar bolts for immediate support until cable bolts cure, leading to delays and safety concerns, and result in significant tension loss due to the limited length of cable that can be tensioned effectively.

Innovation Solution

A machine and method that includes a drill, grout delivery system, cable dispensing arrangement, and a rotatable cartridge with bore anchors to allow immediate tensioning of cable rock bolts, eliminating the need for primary bolts and reducing tension loss by anchoring the cable at the leading end, enabling full-length tension application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cable rock bolts are installed using traditional grout curing methods, then the cable bolts can provide long-term strata support, but the installation process requires waiting 3-4 weeks for full curing, delaying tunnel development

Engineering Contradiction:
Improvestrata supportVSAvoidcuring time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-installing solid bar primary bolts that provide immediate strata support before the cable bolt grout cures. This preliminary support system is in place during the entire curing period, ensuring continuous protection while eliminating the waiting time for cable bolt effectiveness.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses solid bar primary bolts as an intermediary support system that bridges the time gap between cable bolt installation and grout curing. The primary bolts serve as a temporary but effective mediator that maintains strata stability until the cable bolts become fully operational.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If primary solid bar bolts are installed to provide immediate support, then strata stability is maintained during curing, but the overall support system requires two stages and increases device complexity

Engineering Contradiction:
Improveimmediate supportVSAvoidtwo-stage installation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the functions of primary immediate support and secondary long-term support into a coordinated two-stage system where solid bar primary bolts and cable bolts work together. The primary bolts provide immediate support while the cable bolts provide long-term support, and both are installed and integrated as part of a unified support strategy.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If cable bolts are tensioned after grout curing, then the cable is securely held in the bore, but significant tension loss occurs because only the short protruding end (0.3m) can be effectively tensioned

Engineering Contradiction:
Improvecable anchoringVSAvoidtension loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies preliminary action by pre-anchoring the leading end of the cable to the rock face using a rock plate and anchor mechanism before tensioning. This preliminary anchoring creates a secure fixed point that allows the full length of the cable to be effectively tensioned, eliminating tension loss along the embedded portion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a rock plate that replicates the anchoring function at the rock face, creating a counterbalance to the cable tension. The rock plate with its anchor mechanism effectively copies the anchoring capability, allowing tension to be applied uniformly throughout the cable length rather than losing tension in the embedded portion.

Inventive Principle:
Principle #26Copying

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

Provides immediate strata support, reduces installation time and personnel requirements, and minimizes tension loss, allowing for safer and more efficient tunnel development with reduced reliance on specialized equipment and personnel.

Implementation Method 1

a drill for drilling a bore into a rock wall

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

a grout delivery system for delivering grout into the bore

Methodology Applied
Scientific EffectPressure Gradient: Pressure Gradient

Implementation Method 3

a cable anchoring mechanism for anchoring the leading end of the cable within the bore

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 4

a cable tensioning mechanism for applying tension to the cable to place the rock substrate in compression

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2920418B1A machine and method for installing rock bolts
Publication Date: 2022.08.17 SANDVIK INTELLECTUAL PROPERTY AB
  • EP2920418B1 patent drawingFigure 1a~1f
  • EP2920418B1 patent drawingFigure 2~3

AI summary

A machine (10) for installing cable bolts, including a drill (11) for drilling a bore (12) into a rock wall (13), a grout delivery system (15) for delivering grout (16) into the bore (12), a cable dispensing arrangement (24) for dispensing cable (23) into the bore (12), an attachment device (30) for attaching a bore anchor (21) to the leading end (22) of the cable (23) prior to the cable bolt being fed into the bore (12), and a severing device (35) for severing the cable (23) to form a trailing end (40). A method of installing a cable rock bolt into a bore is also provided.