Tower Crane Hook Height Sensing for Precise Load Lowering
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Solution Overview
Problem
Existing cranes, such as tower and telescopic jib cranes, face challenges in precisely controlling the lowering depth of the load hook due to unknown sling lengths, varying load dimensions, and poor visibility, necessitating a spotter for safe and precise load maneuvering, which is not feasible in all conditions.
Innovation Solution
A crane equipped with a detection device featuring downward-facing optical sensors, such as stereoscopic cameras, measures the distance from the load-handling device to the ground or objects below, providing accurate height information for precise control without a spotter, using triangulation to determine vertical distances and offering a 3D view of the surroundings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a spotter is used to communicate load position, then visibility and communication of load hook position is improved, but dependency on external personnel and communication equipment is increased
Solution Approach 1:
The crane system performs self-measurement of load position using onboard sensors (laser distance meters, encoders) and automatically calculates and transmits position data, eliminating the need for external spotters and communication equipment
Solution Approach 2:
The patent replaces the mechanical/human spotter system with an automated electronic measurement and communication system using lasers, sensors, and digital data transmission to provide load position information
2Device complexity
If lowering depth is measured from load-handling device to crane boom, then measurement simplicity is improved, but accuracy is worsened due to unknown ground elevation and sling lengths
Solution Approach 1:
Instead of measuring upward from the load to the crane boom, the system measures downward from the load-handling device to the ground using laser distance meters, inverting the measurement direction to obtain accurate vertical distance data
Solution Approach 2:
The patent introduces intermediate measurement components (laser distance meters mounted on the load-handling device, encoders on the hoist rope) that directly measure vertical distance to the ground, serving as mediators between the load and ground elevation
3Reliability
If remote control is used to improve visibility, then operator safety is improved, but response time and control precision are worsened
Solution Approach 1:
The system provides real-time feedback of load position, vertical distance, and environmental contours to the operator through display devices, enabling precise control decisions without delay while maintaining safety through automated measurements
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 smooth and jerk-free lifting and lowering of loads by accurately determining the vertical distance and environmental contours, allowing autonomous or semi-autonomous control of the load-handling device, even in conditions of poor visibility or lack of a spotter.
Implementation Method 1
downward-facing optical sensors, such as stereoscopic cameras, measures the distance from the load-handling device to the ground or objects below, providing accurate height information for precise control without a spotter, using triangulation to determine vertical distances
Data Source
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AI summary
The invention relates to a crane, in particular a rotating tower crane, comprising a crane boom, from which a load-receiving means such as load hooks can be raised and lowered by means of a hoist rope, wherein a detection device is provided for detecting the distance of the load-receiving means from the ground and/or from an object located below the load-receiving means.