Shape-Locked Centralizer for Drill Rod Retention
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Solution Overview
Problem
Existing centralizers in rock drilling units rely on spring force to keep the closing element closed, which is insufficient to prevent opening under the forces exerted by drill rods or other excavation implements during normal operation.
Innovation Solution
The closing element of the centralizer is locked in a shape-locked manner using mutually shape-locking locking members, including elongated transfer openings and a pivot pin, with a push rod mechanism that maintains the locking position without needing to counteract all opening forces, ensuring the drill rod is retained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring force is used to keep the closing element closed, then the closing element can be simple in structure, but it is insufficient to prevent opening under forces exerted by drill rods during normal operation
Solution Approach 1:
The patent changes the locking mechanism from spring-based force balancing to shape-based geometric locking. The closing element and locking members are designed with specific shapes (elongated transfer openings, pivot pin geometry) that create inherent mechanical interlocking, eliminating the need for spring force to counteract operational loads.
Solution Approach 2:
The patent extracts the spring force element from the locking mechanism, removing the reliance on elastic force. Instead, the locking function is achieved through the geometric configuration of the locking members and transfer openings, which provide passive mechanical locking without active force generation.
2Reliability
If spring force is used to maintain closing element position, then the mechanism can be simple, but additional force is needed to counteract all opening forces during operation
Solution Approach 1:
The patent transitions from force-based parameter control (spring force magnitude) to geometry-based parameter control (shape of locking members and transfer openings). The elongated transfer openings and pivot pin create a mechanical configuration that inherently resists opening forces through geometric constraints rather than force generation.
Solution Approach 2:
The patent removes the spring force component entirely from the force balance equation. The closing element stability is maintained not by generating counteracting force, but by creating geometric interlocking that prevents motion without requiring force generation during normal operation.
3Reliability
If shape-locked locking members are used, then rod retention is improved, but the device complexity increases due to additional locking mechanisms
Solution Approach 1:
The locking members serve multiple functions: they provide shape-based locking, guide the closing element motion through elongated transfer openings, and enable automatic locking/unlocking through the pivot pin mechanism. This multi-functionality reduces the need for separate components for each function.
Solution Approach 2:
The shape-locked locking mechanism operates automatically based on the geometric configuration. When the closing element moves to the closed position, the pivot pin automatically engages with the elongated transfer openings to create the locked state without requiring external actuation or complex control mechanisms.
Data Source
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AI summary
The invention relates to a method for manipulating drill rods, to a centralizer and to a rock drilling unit. It is possible to introduce rods (9, 18) into the centre (K) of a rock drilling unit (4) or a bolting device by means of a changing device (13), and to remove from the centre. The rod locating in the centre is supported by a centralizer (16), through the central opening (20) of which the rod is arranged. The centralizer comprises a closing element (22) which is opened and closed in accordance with the operation of the changing device. The turning of the changing device affects a push rod (25) which releases the shape-locking of the closing element and transfers it to the open position. When the changing device is turned back to the normal position, a force member (26) returns the push rod to the normal position and simultaneously the closing element is shape-locked again. In the closed position the closing element is rigidly shape locked.