Kelly Bar Speed Control for Drilling Safety
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Solution Overview
Problem
Existing construction machines with telescoping Kelly linkages face challenges in efficiently and safely retracting and extending Kelly rods during drilling operations, risking material stress and damage due to rapid movement, especially when approaching the ground or top drive.
Innovation Solution
An automatic control device is implemented to manage the Kelly linkage's movement, switching between high-speed and gentle driving modes based on critical areas, using the main cable winch and top drive actuating device to control the speed, ensuring quick extension/retraction in non-critical zones and reduced speed in critical areas to prevent impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the Kelly bar is moved quickly to achieve rapid drilling progress, then productivity is improved, but the risk of material stress and damage increases
Solution Approach 1:
The patent applies dynamics by enabling the Kelly bar system to switch between different movement states: high-speed mode for rapid extension/retraction in non-critical zones, and low-speed mode for precise control in critical areas. The control device dynamically adjusts the speed based on the operational phase, allowing the system to adapt its motion characteristics to minimize damage risk while maintaining productivity.
Solution Approach 2:
The patent implements local quality by applying different speed control strategies to different spatial zones of the Kelly bar movement. Critical areas (near the ground and power rotary head) receive special low-speed control, while non-critical intermediate zones allow high-speed operation. This localized differentiation of movement quality resolves the contradiction between overall speed and localized safety.
2Productivity
If the Kelly bar is extended and retracted frequently during discontinuous soil cultivation, then productivity is improved, but the time required for each extension/retraction cycle increases
Solution Approach 1:
The patent applies periodic action by implementing a cyclical high-speed/low-speed movement pattern during Kelly bar extension and retraction. The system operates in high-speed mode during most of the travel distance, then switches to low-speed mode only during critical phases near the endpoints. This periodic variation in speed maintains high average productivity while ensuring safety during critical transitions.
Solution Approach 2:
The control device performs preliminary action by anticipating critical zones and preparing for speed reduction in advance. Before the Kelly bar enters critical areas (detected through position monitoring), the control system proactively reduces speed to prevent damage. This preliminary speed adjustment prevents reactive damage response and optimizes the timing of speed changes.
3Reliability
If the speed is reduced in critical areas to prevent impact, then reliability is improved, but the overall working speed decreases
Solution Approach 1:
The patent applies partial action by restricting low-speed operation to only the necessary critical zones rather than the entire travel distance. The Kelly bar operates at high speed for the majority of its extension and retraction stroke, then transitions to low speed only when approaching critical areas (ground level and power rotary head). This partial application of speed reduction maintains overall working speed while ensuring reliability where needed.
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
This solution enhances working efficiency while minimizing the risk of material damage and tool destruction by precisely controlling the Kelly linkage's movement, allowing for faster drilling progress without compromising safety.
Implementation Method 1
an inner Kelly bar which comprises a rope suspension for a rope through which the inner Kelly bar is vertically movable by means of a main winch
Implementation Method 2
a power rotary head is vertically movable by means of an adjusting device
Data Source
Figure 2
AI summary
The invention relates to a working machine and a method for cultivating soil with a working machine having a mast along which a power rotary head is vertically movable by means of an adjusting device, through which a telescopic Kelly bar is slidably guided, which has at least an outer Kelly bar designed to rest on the power rotary head, and an inner Kelly bar which includes a rope suspension for a rope through which the inner Kelly bar is moved vertically by means of a winch, wherein the soil is cultivated with a soil cultivation tool which is attached to a lower end of the Kelly bar.According to the invention, the actuating device for the power rotary head and/or the main winch for the Kelly bar is automatically controlled by means of a control device, wherein the inner Kelly bar is moved relative to the power rotary head in a high-speed mode with a first speed in some areas and in a low-speed mode in others, in which the speed is reduced compared to the first speed of the high-speed mode.