Crawler Crane Hoist Drum Rope Pressing for Uniform Winding
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Solution Overview
Problem
Existing cranes face issues with rope winding irregularity when the boom is perpendicular to the ground, as the pressing force of the presser roller decreases, leading to improper rope arrangement on the drum.
Innovation Solution
A crane design featuring a rope holding device with an oscillating arm and weight member that generates a moment with the support shaft as a fulcrum, ensuring the rope is pressed against the drum regardless of the boom's posture, using a weight member to bias the oscillating arm towards the drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spring-biased presser roller is used to press the rope against the drum, then the rope can be wound arranged when the boom is inclined, but the pressing force decreases when the boom is perpendicular, causing irregular winding
Solution Approach 1:
The patent applies the counterweight principle by introducing a weight member that generates a moment to counteract the decreasing pressing force. The weight member creates a gravitational moment around the support shaft that compensates for the moment caused by boom posture changes, thereby maintaining consistent pressing force on the rope regardless of whether the boom is inclined or perpendicular to the ground.
Solution Approach 2:
The patent changes the physical parameters of the pressing mechanism by adding a weight member with specific mass and positioning. This modifies the force characteristics of the presser roller, transforming it from a spring-only biased system to a combined spring-weight biased system, which alters the pressing force parameter to remain constant across different boom angles.
2Length of moving object
If the boom posture changes to perpendicular position, then the crane achieves maximum lifting height, but the presser roller generates a moment away from the drum, reducing rope pressing effectiveness
Solution Approach 1:
The weight member acts as a counterbalancing element that generates a moment in the opposite direction to the boom posture-induced moment. When the boom is perpendicular, the weight member's gravitational moment counteracts the moment that would otherwise cause the presser roller to press away from the drum, ensuring continuous effective pressing throughout the full range of boom motion including maximum lifting height.
Solution Approach 2:
The patent introduces dynamic adaptability to the pressing mechanism through the weight member, which automatically adjusts the pressing force distribution based on boom posture. As the boom moves from inclined to perpendicular position, the weight member's moment arm changes, dynamically compensating for the varying pressing requirements to maintain reliable rope winding arrangement across all operating positions.
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 design allows for consistent, arranged rope winding on the drum across various boom postures, preventing irregular winding and maintaining rope durability.
Implementation Method 1
a weight member which biases a distal end side of the oscillating arm in a direction close to the drum by the gravity with the support shaft as a fulcrum, is provided in the proximal end of the oscillating arm
Data Source
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AI summary
Provided is a crawler crane in which a rope is wound in a state where the rope is closely arranged on a drum of a hoisting winch regardless of a posture of a boom. A crawler crane includes a main winding winch 19 having a main winding drum 21 and a rope holding device 25 which presses a main winding rope 23 wound around a main winding drum 21 of the main winding winch 19 against the main winding drum 21. The rope holding device 25 is configured to include an oscillating arm 28 whose distal end 28H oscillates in a direction close to or away from the main winding drum 21 with a support shaft 27 as a fulcrum, and a presser roller 29 which is attached to the distal end 28H of the oscillating arm 28 and abuts against the main winding rope 23 wound around the main winding drum 21. A weight member 31, which biases the distal end 28H of the oscillating arm 28 in a direction close to the main winding drum 21 by the gravity with the support shaft 27 as a fulcrum, is provided at a proximal end 28G of the oscillating arm 28.