Hydraulic Gripper Jaw Positioning for Variable Drilling Tools

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Solution Overview

Problem

Existing rock drilling tool handling systems face challenges in efficiently accommodating tools of varying dimensions and require improved control over gripping mechanisms to enhance versatility and compatibility with existing drilling units.

Innovation Solution

A gripper system utilizing a hydraulic cylinder with an adjusting piston that provides three operational modes (open, guiding, and gripping) and a hydraulic cylinder with three pressure spaces, allowing precise control of gripping jaw positions, enabling versatile handling of different drilling tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional hydraulic cylinder with two positions is used, then the structure is simple, but the gripper lacks versatility in handling drilling tools of different dimensions

Engineering Contradiction:
Improvegripper adaptabilityVSAvoidhydraulic cylinder complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The hydraulic cylinder is segmented into multiple chambers (first and second chambers) with an adjusting piston that can be positioned at different locations. This segmentation allows the cylinder to provide multiple distinct piston rod positions (first, second, and third positions) corresponding to different gripping modes, thereby enabling the gripper to handle drilling tools of different dimensions without requiring multiple separate cylinders.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adjusting piston is made movable within the hydraulic cylinder, allowing dynamic reconfiguration of the chamber volumes. By moving the adjusting piston between different positions, the system can dynamically switch between different gripping modes (open mode, guiding mode, gripping mode), providing adaptability while maintaining a single integrated cylinder structure.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If the gripping jaw movement range is limited to two extreme positions, then the control is simple, but the gripper cannot provide intermediate positioning for guiding mode

Engineering Contradiction:
Improvecontrol simplicityVSAvoidgripping mode versatility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The hydraulic cylinder is divided into multiple controllable chambers that can be independently pressurized or depressurized. This segmentation enables the system to achieve three distinct piston rod positions (fully retracted, intermediate, fully extended) by controlling different chamber combinations, providing both intermediate positioning capability and simple binary control through valve selection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the volume parameters of the hydraulic chambers by moving the adjusting piston to different positions. This parameter change enables the piston rod to achieve different extension lengths, thereby providing multiple gripping modes (open, guiding, gripping) with a single hydraulic cylinder through controlled volume variation.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If existing gripper designs are used, then compatibility with current systems is maintained, but versatility in handling drilling tools with different dimensions is limited

Engineering Contradiction:
Improvetool handling versatilityVSAvoidretrofitting complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The hydraulic cylinder is designed with multi-functionality, serving as both the actuator for gripping motion and the mechanism for providing multiple positioning modes. The adjusting piston with multiple possible positions allows the same cylinder to perform different functions (open mode, guiding mode, gripping mode), making the gripper universally applicable to various drilling tool dimensions without requiring multiple specialized actuators.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The movable adjusting piston enables dynamic reconfiguration of the hydraulic cylinder's internal geometry, allowing the system to adapt its characteristics to match different tool requirements. This dynamic capability provides versatility in handling various drilling tool dimensions while maintaining a compact, integrated structure that can be retrofitted to existing systems.

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

The gripper system offers improved control and adaptability in handling drilling tools of various dimensions, facilitating retrofitting to existing units and ensuring secure grip or gentle guidance as needed.

Implementation Method 1

The hydraulic cylinder comprises at least one adjusting piston movable in the hydraulic cylinder by means of hydraulic pressure

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP4461920B1Gripper, rock drilling unit and method
Publication Date: 2025.09.17 SANDVIK MINING & CONSTR OY
  • EP4461920B1 patent drawingFigure 1~2
  • EP4461920B1 patent drawingFigure 3~6
  • EP4461920B1 patent drawingFigure 7~8

AI summary

A gripper, a rock drilling unit and a method of handling drilling tools. The gripper (9) comprises a hydraulic cylinder (10) and at least one gripping jaw (12) movable by means of the hydraulic cylinder towards and away from the drilling tool (7). The hydraulic cylinder comprises at least one adjusting piston (16) having a first operating position with a first fixed stoppage and a second operating position with a fixed second stoppage. The adjusting piston limits movement length of a piston rod (11) at one of the first and second operating positions to provide the gripping jaw an intermediate position between extreme movement positions of the gripping jaw.