Crane Winch Variable Threshold for Free Fall Control
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Solution Overview
Problem
Existing crane winch devices have a fixed clutch pressure for speed-increasing assist, leading to deviations in the falling speed of suspended loads from the operator's expectations, impairing workability, especially when the suspended load is light and affected by viscous resistance.
Innovation Solution
A crane winch device with a variable first threshold for initiating speed-increasing assist, allowing for proper timing adjustments through an adjustable unit, enabling the winch drum to freely fall by varying the braking force, thereby improving the alignment with the operator's intentions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed clutch pressure is used for speed-increasing assist, then the control system is simple, but the falling speed of suspended loads deviates from operator expectations, impairing workability
Solution Approach 1:
The patent applies dynamics by making the clutch pressure threshold variable rather than fixed. The adjustment unit allows the first threshold to be changed based on operating conditions, enabling the control system to adapt to different scenarios and achieve more accurate speed-increasing assist control, thereby improving workability without excessive complexity
Solution Approach 2:
The patent implements parameter changes by allowing the clutch pressure threshold (first threshold) to be adjusted. This enables the system to optimize the timing for initiating speed-increasing assist under different conditions, resolving the contradiction between operational ease and control precision
2Reliability
If the brake unit applies sufficient braking force to control heavy loads, then load control is reliable, but light loads cannot smoothly and freely fall due to viscous resistance
Solution Approach 1:
The patent applies partial action by having the brake unit provide only the necessary braking force to enable smooth free fall of light loads, rather than maintaining maximum braking force. When the suspended load is light, the brake unit applies minimal braking force just sufficient to overcome viscous resistance, allowing smooth free fall while maintaining reliability when needed
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the braking force based on load weight. The control unit varies the brake unit's output according to the actual load conditions, enabling light loads to fall smoothly while maintaining reliable control for heavier loads
3Ease of operation
If speed-increasing assist is initiated at a fixed clutch pressure threshold, then the control logic is simple, but the assist timing does not align with operator expectations
Solution Approach 1:
The patent applies dynamics by making the clutch pressure threshold adjustable rather than fixed. The adjustment unit enables the first threshold to be modified according to operator preferences and operating conditions, allowing the speed-increasing assist to be initiated at the optimal moment and aligning with operator expectations
Solution Approach 2:
The patent implements feedback by allowing operator input through the adjustment unit to modify the first threshold. This creates a feedback loop where operator experience and observations are incorporated into the control parameters, improving timing alignment without excessive system complexity
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 variable threshold allows for precise control of the speed-increasing assist, ensuring the suspended load falls smoothly and freely, enhancing workability by fine-tuning the assist timing based on load weight and operator skill levels.
Implementation Method 1
a brake unit that brakes the winch drum
Implementation Method 2
a hydraulic motor that rotationally drives the winch drum in the rope delivery direction
Implementation Method 3
a free fall function to rotate a winch drum in a rope delivery direction by using a weight of a suspended load
Data Source
AI summary
There is provided a crane winch device allowing a suspended load to freely fall due to a load thereof. The crane winch device includes a winch drum around which a rope for suspending the suspended load is wound, braking brake unit that brakes the winch drum, speed-increasing unit that performs speed-increasing assist of the winch drum in a direction of free fall acceleration when a braking force of the brake unit is smaller than a first threshold, and an adjustment unit that adjusts the first threshold.