Tower Crane Pulley Block End-Position Detection
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Solution Overview
Problem
The existing manual determination of the high-end position of a crane's raceway is imprecise and not reproducible, leading to suboptimal crane usage and increased safety risks due to the need for additional safety margins.
Innovation Solution
An automatic process that determines the physical position at the end of the crane's raceway by measuring the effort on the lifting cable using a load sensor, allowing for precise and reproducible calculations of the maximum end-of-race position without adding equipment to the crane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual determination of end-of-travel position is used, then the crane can be set up quickly, but the positioning precision is poor and safety margins must be increased
Solution Approach 1:
The system automatically determines the end-of-travel position using the load sensor already present on the crane. The control command system autonomously processes load measurements to identify when the block reaches the distribution trolley, eliminating the need for manual positioning while achieving precise and reproducible results.
Solution Approach 2:
The manual visual estimation method is replaced with an automated electronic system that uses load sensor measurements to detect the end-of-travel position. The control command system processes the load data to automatically determine when the block contacts the distribution trolley, substituting human judgment with automated electronic detection.
2Reliability
If additional safety margins are added to the end-of-travel position, then safety is improved, but the crane's lifting capacity and efficiency are reduced
Solution Approach 1:
The system replaces manual visual estimation with automated electronic detection using load sensors. This substitution enables precise determination of the actual end-of-travel position, allowing the crane to operate closer to the true limit without excessive safety margins, thereby maximizing lifting capacity while maintaining safety.
Solution Approach 2:
The control command system continuously monitors load sensor measurements during block ascent and automatically identifies the end-of-travel position based on load characteristics. This feedback mechanism ensures the block stops at the precise location where it contacts the distribution trolley, eliminating the need for conservative safety margins.
3Measurement precision
If electronic devices are added to automatically stop the block, then positioning precision is improved, but the device complexity increases
Solution Approach 1:
The load sensor already present on the crane for measuring lifting loads is given an additional function: detecting the end-of-travel position. By analyzing load characteristics during block ascent, the same sensor serves dual purposes, eliminating the need for separate positioning detection equipment and reducing overall system complexity.
Solution Approach 2:
The end-of-travel detection function is merged with the existing load measurement system. The control command system combines load sensor data with block position information to automatically determine when the block reaches the distribution trolley, integrating multiple functions into existing components rather than adding separate systems.
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
The automatic process reduces human error, saves time during crane setup, optimizes crane performance by reducing safety distances, and enhances safety by ensuring precise positioning of the crane's components.
Implementation Method 1
a force on a strand of the lifting cable is measured by a monitoring device, said physical end-of-travel position, which corresponds to a position in which the block is physically in contact with the distribution trolley, being reached and determined as a function of a variation in the force on the strand of the lifting cable
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to an automatic method for determining the physical end-of-travel position (zphys) of a pulley block (2) of a crane (1) that can be moved up and down by means of a lifting cable (3). The method comprises a lifting phase of the pulley block (2) during which the force on a strand (30) of the lifting cable is monitored by a monitoring device (4), which may be a load sensor such as a strain gauge shaft. The physical end-of-travel position is reached and determined based on a variation in the force on the strand of the lifting cable. From this physical end-of-travel position, a maximum end-of-travel position (zmax) can be determined, which is a position that the pulley block must not exceed when the crane is in operation.