Partially Annular Jaw Spring for Drill Head Chuck Release
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Solution Overview
Problem
Current hydraulically actuated chucks for drill heads often fail to fully open, preventing larger diameter components like core barrel assemblies and drill bits from passing through, due to inadequate urging means that can make installation more difficult and complicate drill string handling.
Innovation Solution
A partially annular jaw spring with tool engagement means and a fixing mechanism is used to ensure the jaws can move radially far enough to release larger components, providing sufficient spring force and ease of installation by forming an inside seat for the jaw spring and using flat cross-section design with recesses and through holes for accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional urging means are used to move jaws from grip to release position, then the chuck can release drill string, but larger diameter components cannot pass through due to insufficient jaw movement range
Solution Approach 1:
The patent changes the physical parameters of the urging means by replacing conventional springs with an elastomeric material element that exhibits hyperelastic behavior. This material can undergo extremely large deformations (greater than 100% strain) while maintaining sufficient restoring force, thereby enabling the jaws to move through the full range required to pass both drill string and larger diameter components reliably.
Solution Approach 2:
The patent employs composite construction by combining the elastomeric material with a rigid support structure and hydraulic actuator system. The elastomeric element works in conjunction with the hydraulic cylinder and jaw mechanisms to achieve the required movement range and force characteristics that neither component could provide alone.
2Length of moving object
If stronger urging means are used to push jaws further back, then larger components can pass through, but installation becomes more difficult
Solution Approach 1:
The elastomeric material element is designed to be flexible and adaptable during installation. Its viscoelastic properties allow it to be compressed or deformed during the installation process to fit into the confined space between the hydraulic cylinder and the jaws, then it automatically returns to its functional shape once installed, providing the required urging force without requiring complex installation procedures.
3Ease of manufacture
If conventional urging means are used, then installation is simpler, but the jaws cannot be moved sufficiently to release larger components
Solution Approach 1:
The elastomeric material's ability to undergo extreme deformation allows the same urging mechanism to accommodate different operational requirements - whether gripping standard drill string or releasing larger diameter components. The material's force-displacement characteristics can be tailored through material selection and geometry to provide appropriate urging force across the full range of motion required for versatile component handling.
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 solution allows for consistent passage of larger diameter components through the chuck, simplifying drill string assembly and disassembly by ensuring the jaws can be reliably moved to the release position with sufficient force and ease of handling, addressing the limitations of existing urging means.
Implementation Method 1
a jaw spring (8) arranged for influencing the jaws (7) into a release position
Implementation Method 2
The jaw spring is partially annular for surrounding said axis in its mounted position
Data Source
AI summary
A chuck for a drill head of a rotation rock drilling rig, wherein a plurality of jaws are equally angularly distributed around a grip position axis, wherein the jaws co-operate with actuator means for radial movements of the jaws, and wherein the chuck includes urging means being arranged for influencing the jaws into the release position. The urging means is a partially annular jaw spring surrounding said axis and having two spring ends adjacent to each other. The jaws together form an inside seat for the jaw spring and the jaw spring is arranged for fixing engagement with one of the jaws. The invention also relates to a drill head, a rig and a jaw spring.