Crane Boom Warp Control via Mid-Support Winch
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Solution Overview
Problem
Conventional cranes face challenges in minimizing the warp of their raising members due to varying angles and cargo weights, leading to excessive bending moments and potential damage.
Innovation Solution
A crane design incorporating a mid-support structure with a mid-support winch and rope system that adjusts the tension and distance of the mid-support rope to control the warp of the raising member, using a controller to manage the winching operations based on detected load and angle data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the boom is made longer to increase working radius, then the lifting capacity is improved, but the boom warps more by its own weight causing larger bending moments
Solution Approach 1:
A mid-support line is introduced as an intermediary element connecting the middle portion of the jib to the guyline. This mid-support line acts as a mediator to provide additional support to the jib, reducing the bending moment caused by the boom's weight and the lifted load, thereby allowing longer booms without excessive warping
2Device complexity
If both ends of the mid-support line are secured to the jib and guyline, then the structure is simplified, but the degree of warp cannot be suppressed to a minimum for different raised angles and cargo weights
Solution Approach 1:
The mid-support line is modified from a fixed structure to a dynamic adjustable system. A reel mechanism is introduced to wind and unwind the mid-support line, allowing the tension and length to be adjusted according to different raised angles of the jib and different cargo weights. This dynamic adjustment enables optimal warp suppression for various operating conditions
3Ease of operation
If the distance between sheaves is adjusted to raise and lower the boom, then the raising operation is enabled, but the warp of the boom cannot be corrected while the raised angle is kept constant
Solution Approach 1:
The support system is segmented into two independent functions: the guyline system for raising and lowering the boom, and the mid-support line with reel mechanism for correcting warp. This segmentation allows the warp correction function to operate independently while the boom raised angle remains constant, solving the limitation of the integrated sheave system
Data Source
AI summary
There is provided a crane that is capable of adjusting the warp of a raising member mounted on a supporting body to be raised and lowered, where the adjustment is made according to a posture of the raising member and load of a cargo. The crane includes a crane body, a boom, a raising device, a main rope, a main winch, a mid-support rope, a mid-support winch, and a manipulation unit. The mid-support rope connects a middle portion of the boom to the guylink and includes a securing end P secured to the guylink. The mid-support winch winds up and winds out the mid-support rope to change the distance between the guylink and the boom.