Drilling Locking Device Latch Spring Gravity Balance
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Solution Overview
Problem
Existing locking devices for drilling operations, such as those with spring-loaded latches and chain latches, face issues like inadequate holding force, complex maintenance requirements, and difficulty in unlocking underground, posing safety risks and operational challenges.
Innovation Solution
A locking device featuring an elongated locking body with pivotally attached latches, a tubular piston, and a pressure spring mechanism, allowing the latches to be held in an extended position for drilling and retracted for raising samples, with a release tube mechanism to compress the spring and unlock the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If spring-loaded latches are used to lock the core barrel, then the device is simple to operate from the surface, but the spring force is insufficient to hold the pin in place underground, causing the latch to slip and disengage
Solution Approach 1:
The patent uses gravity as a counterweight force to balance the spring force. A weight is attached to the latch mechanism such that the gravitational force on the weight counteracts the spring force, creating a balanced system where the latch remains firmly engaged. This prevents the latch from slipping or disengaging due to insufficient spring force alone.
Solution Approach 2:
The patent changes the physical parameters of the locking system by introducing a mass element whose gravitational force can be adjusted. By varying the mass of the weight, the system can be tuned to provide the appropriate holding force for different drilling conditions, thereby improving reliability while maintaining operational simplicity.
2Reliability
If chain type latches are used to lock the core barrel, then the locking force is sufficient, but the device becomes complicated and requires frequent maintenance due to spring breakage
Solution Approach 1:
The patent merges the advantages of both spring-loaded and chain latches into a single hybrid mechanism. The spring provides the necessary locking force, while the gravity-balanced weight ensures stable engagement. This combination eliminates the need for complex chain mechanisms while maintaining sufficient locking force and reducing maintenance requirements.
Solution Approach 2:
The patent extracts and eliminates the problematic chain components from the locking mechanism. By replacing the entire chain latch system with a simplified spring-gravity balanced latch, the design removes the sources of frequent breakage and maintenance issues while retaining the essential locking function.
3Reliability
If chain type latches are used, then adequate locking force is achieved, but a long stroke is required for latch retraction, making it difficult to unlock once underground
Solution Approach 1:
The gravity-balanced weight not only provides holding force but also assists in the retraction process. When unlocking is required, the latch mechanism can be easily pulled back a short distance, and the weight's gravity automatically helps reset the latch to its engaged position, eliminating the need for long manual retraction strokes.
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
Enhances operator safety and reliability, allows for efficient drilling and core retrieval, and reduces maintenance costs by providing a simpler and more effective locking mechanism suitable for both downhole and uphole operations.
Implementation Method 1
a pressure spring mechanism mounted on the top of the latch body and urging the plunger toward the latches to hold them in their extended position
Implementation Method 2
a pull exerted on the release tube integral with the piston compresses the spring mechanism
Data Source
Figure 1~3
AI summary
The invention relates to a locking device for a drilling device including a locking body that is mountable in an outer tube, an unlocking tube that is slidingly mountable about the locking body, two catches attached to the locking body and pivotable between an extended position, in which the catch engages with the outer tube in order to lock the locking body to said outer tube, and a retracted position for unlocking the locking body from the outer tube, a piston sliding around the locking body and rigidly connected to the unlocking tube, and a compression-spring mechanism pressing the piston towards the catches in order to retain said catches in the extended position thereof, a pull exerted on the unlocking tube compressing the spring mechanism to prevent the piston from pressing against the catches which are positioned in the retracted position thereof.