Core Barrel Head Latch Mechanism for Horizontal Drilling Recovery
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Solution Overview
Problem
Conventional core barrel heads struggle to reliably recover inner tubes during geological sampling in horizontal and rising gradient directions, leading to delays and increased construction costs due to the unavailability of gravity for latch disengagement and difficulties in pressing the overshot into the outer tube without water escape.
Innovation Solution
A core barrel head design featuring a main shaft with an inner fixing latch, a latch disengagement slide tube, and a slide tube fixing latch, utilizing elastic biasing forces to engage and disengage the latch from a locking groove, and an inner tube recovery method that includes releasing the latch disengagement slide tube, inclining the latch inclination preventing part, and using water pressure or a wire to recover the inner tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional latch mechanism is used that relies on gravity for disengagement, then the structure is simple, but the inner tube cannot be recovered in horizontal or rising gradient directions
Solution Approach 1:
The patent replaces the gravity-dependent mechanical latch disengagement system with a hydraulic actuation system. The latch is disengaged by applying water pressure through the overshot to move the latch slide tube, which tilts the latch to release it from the locking groove. This substitution allows the latch to be disengaged reliably in any excavation direction (horizontal, rising gradient, etc.) without depending on gravitational force.
Solution Approach 2:
The patent employs hydraulic pressure (water pressure) to actuate the latch disengagement mechanism. When water pressure is applied through the overshot during inner tube recovery, it moves the latch slide tube in the axial direction, causing the latch to tilt and disengage from the locking groove. This hydraulic actuation method ensures reliable latch release regardless of the excavation direction or orientation of the outer tube.
2Force
If the outer tube is removed and water pressure is applied without rotation, then water pressure can be applied to the overshot, but there is no escape place for water making it difficult to press the overshot in
Solution Approach 1:
The patent incorporates a water escape path formation mechanism that creates an escape path for water before water pressure is applied to the overshot. The latch slide tube has a water escape path formation portion that, when the latch is tilted, opens a passage allowing water to escape. This preliminary preparation of the water escape path enables smooth overshot insertion by water pressure without water accumulation or resistance.
3Reliability
If the inner tube is pulled out together with the outer tube, then the inner tube can be recovered, but construction period is delayed and construction costs increase
Solution Approach 1:
The patent replaces the gravity-dependent mechanical latch disengagement system with a hydraulic actuation system. The latch is disengaged by applying water pressure through the overshot to move the latch slide tube, which tilts the latch to release it from the locking groove. This substitution allows the latch to be disengaged reliably in any excavation direction (horizontal, rising gradient, etc.) without depending on gravitational force.
Solution Approach 2:
The patent employs hydraulic pressure (water pressure) to actuate the latch disengagement mechanism. When water pressure is applied through the overshot during inner tube recovery, it moves the latch slide tube in the axial direction, causing the latch to tilt and disengage from the locking groove. This hydraulic actuation method ensures reliable latch release regardless of the excavation direction or orientation of the outer tube.
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
Enables reliable recovery of the inner tube with collected geological samples in horizontal and rising gradient directions, reducing construction delays and costs by facilitating latch disengagement and overshot insertion without requiring a water swivel.
Implementation Method 1
an inner fixing latch that is expanded outward of the main shaft by a biasing force of an elastic material so as to engage with a locking groove
Implementation Method 2
an inner tube recovery method that includes releasing the latch disengagement slide tube, inclining the latch inclination preventing part, and using water pressure or a wire to recover the inner tube
Data Source
AI summary
[Problem] To provide: a core barrel head capable of definitely recovering an inner tube in which a geological sample has been collected in a situation where excavation is performed in a horizontal direction and in a rising gradient direction; an inner tube assembly provided with said core barrel head; and an inner tube recovery method.[Solution] The present invention has: a main shaft 31 connected to the rear end of an inner tube 2; an inner fixing latch 32 that is axially supported at a substantially intermediate position along an axial direction of the main shaft 31; a latch disengagement slide tube 33 that is mounted to the outer circumferential surface of the main shaft 31 slidably in the axial direction and that disengages the inner fixing latch 32 from a locking groove 43 by inclining the inner fixing latch 32 against a biasing force; and a slide tube fixing latch 34 that locks the latch disengagement slide tube 33 at a position where the inner fixing latch 31 is in an expansion state and that disengages the lock of the latch disengagement slide tube 33 by being inclined by an overshot.