Electronic Spotter Control for Crane Boom Torque Limiting
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Solution Overview
Problem
Crane operators face challenges in preventing lattice boom overstressing and hydraulic system leakage during pile driving and CFA drilling, particularly at acute angles, leading to potential catastrophic failure, personal injury, and equipment damage due to misalignment and hydraulic drift.
Innovation Solution
A three-axis pivoting boom box with electronic feedback sensors and an onboard electronic control module that maintains the pile lead's alignment with the crane's boom centerline, self-compensates for hydraulic leakage, and limits twist and side loading, using progressive rate rubber springs and electronic sensors to monitor and adjust the spotter's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual or traditional automatic hydraulic steering system is used to keep the pile lead's front attachment face at 90 degrees to the crane's boom centerline, then the crane operator can control the spotter's position, but the system gets out of phase over time due to hydraulic oil leakage and cannot self-compensate, requiring manual bleeding
Solution Approach 1:
The patent employs electronic feedback sensors (such as LVDTs or rotary encoders) that continuously monitor the actual position of the pile lead and spotter. This position data is fed back to the electronic control system, which automatically adjusts hydraulic valve signals to maintain the correct 90-degree alignment. This closed-loop feedback mechanism eliminates the phase drift problem inherent in manual and traditional automatic hydraulic systems by continuously correcting for hydraulic leakage and positional deviations.
Solution Approach 2:
The patent replaces the traditional manual hydraulic steering system with an electronic control system that uses electronic sensors and electronic hydraulic controls. This substitution transforms the purely mechanical/hydraulic control into an electronically-mediated system, enabling precise digital monitoring and adjustment of the spotter's position, thereby eliminating the phase instability caused by hydraulic leakage in traditional systems.
2Adaptability or versatility
If the spotter is swung out from under the lattice boom during sideways batters, then the pile lead can be positioned at the proper inclination, but the operator cannot properly judge the pile lead's alignment with the crane's boom tip, causing misalignment
Solution Approach 1:
The electronic feedback sensors provide continuous, precise digital measurements of the pile lead's actual position and angle relative to the crane's boom centerline. This objective sensor data replaces the operator's subjective visual judgment, enabling accurate alignment verification even when the spotter is swung out during sideways batter operations. The feedback system ensures the pile lead maintains proper inclination while providing exact alignment data.
Solution Approach 2:
The patent replaces the operator's visual alignment judgment with electronic sensing and digital measurement systems. Electronic position sensors and angle sensors provide objective, quantifiable data about the pile lead's alignment status, eliminating the imprecision of human visual estimation and enabling accurate alignment control during complex sideways batter operations.
3Adaptability or versatility
If the pile lead is twisted or side-loaded due to hydraulic drift or torque reaction, then the spotter can handle overhanging loads or drilling torque, but the crane's lattice boom is subjected to excessive stress that can cause catastrophic failure
Solution Approach 1:
The electronic feedback system continuously monitors the position and orientation of the pile lead and spotter, detecting any twisting or side-loading conditions. When deviations are detected, the electronic control system automatically adjusts the spotter's position and orientation to counteract the twisting forces and maintain proper alignment, thereby protecting the lattice boom from excessive stress while preserving the spotter's load handling capability.
Solution Approach 2:
The electronic control system proactively counteracts potential twisting and side-loading forces by continuously adjusting the spotter's position based on real-time sensor feedback. This preliminary anti-action prevents excessive stress from developing in the lattice boom by maintaining proper alignment before catastrophic failure can occur, rather than merely reacting after damage has begun.
Data Source
AI summary
A lifting device such as a mobile crane having a main body and a boom, such as a lattice boom, for supporting a pile lead for, e.g., pile driving or continuous flight auger drilling, and a method of using same. A hydraulically operated mechanical spotter arm may be attached between the device body and the pile lead. Electronic position sensors on the spotter arm may be used to measure angular relationships between the pile lead and the spotter arm. Position sensors on a boom box on the boom may also be used. When the pile lead is swung, information from the sensors may be used by an electronic control system to automatically maintain the pile lead in a desirable position, limiting torque induced in the boom. The boom box position sensors may be used to counter-steer the spotter arm to further limit torque. The boom box may also be fitted with rubber springs to permit controlled pile lead deflection while limiting load transmitted to the boom. Other aspects of the invention will become apparent from the disclosure.