Stationary Hoist Damper for Impulse Load Reduction
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Solution Overview
Problem
Existing hoist systems face high impulse forces during emergency stops, which are not effectively dampened by conventional dampers, leading to excessive loads on the hoist and support structure at any point of the movement path.
Innovation Solution
A stationary hoist with a mechanically attached damper, designed to be rigid during normal operation and provide damping during emergency stops, is installed between the hoist part and the support structure, converting kinetic energy into heat to reduce transmitted momentum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional dampers are used to soften impact at the end of movement path, then impulse forces at the end position are reduced, but impulse forces at any other point of the movement path during emergency stop cannot be dampened
Solution Approach 1:
The hoist system is segmented into multiple independent damping zones along the movement path. Multiple dampers are distributed at different positions (e.g., at the winch, at the load, at intermediate points) so that regardless of where an emergency stop occurs, at least one damper is always in the force transmission path between the moving component and the support structure, ensuring continuous protection throughout the entire movement range.
Solution Approach 2:
The damper system is designed with universal applicability across the entire movement path. The dampers are positioned and configured to handle emergency stops occurring at any position, making the damping system versatile and effective for all possible emergency stop scenarios rather than being limited to a single end position.
2Manufacturing precision
If the damper is designed to be rigid during normal operation, then driving quality and positioning accuracy are maintained, but impulse loads during emergency stop are not reduced
Solution Approach 1:
The damper employs dynamic characteristics with different stiffness values for different operating conditions. During normal operation, the damper maintains a rigid state with high stiffness to ensure precise positioning and driving quality. During emergency stop, the damper transitions to a compliant state with lower stiffness to absorb impulse loads, thus adapting its mechanical properties to the operational requirements.
Solution Approach 2:
The mechanical parameters of the damper, specifically its stiffness, are changed based on the operational state. The damper is designed to exhibit high stiffness during normal operation for precision and low stiffness during emergency stop for冲击 absorption. This parameter change allows the same component to satisfy both precision positioning and impulse load reduction requirements.
3Reliability
If the hoist and support structure are designed for impulse loads, then safety during emergency stop is ensured, but the structure must be oversized for nominal loads
Solution Approach 1:
The damper acts as an intermediary element between the hoist and the support structure. It absorbs and dissipates the impulse energy during emergency stop, preventing these high forces from being transmitted to the support structure. This allows the support structure to be designed for nominal loads only, rather than being oversized to handle emergency impulse loads, thus reducing material usage and cost.
4Force
If dampers are installed between the hoist part and support structure, then impulse forces are reduced during emergency stop, but the damper must be replaced after each emergency stop if plastically deformable
Solution Approach 1:
The mechanical damping system is replaced with a hydraulic damping system. The hydraulic damper uses fluid dynamics to dissipate energy during emergency stop, converting mechanical impulse energy into thermal energy through fluid friction. This allows the damper to absorb repeated emergency stops without permanent deformation, eliminating the need for replacement after each emergency stop and improving ease of repair.
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 solution reduces the maximum load on the hoist and support structure to twice the nominal load during emergency stops, maintaining driving quality and positioning accuracy while preventing plastic deformation and extending the damper's lifespan.
Implementation Method 1
A hydraulic damper is designed in such a way that it is able to convert so much kinetic energy into heat that it does not transfer momentum to the supporting structure at the end of the emergency stop
Data Source
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AI summary
A stationary hoist for moving loads vertically, featuring an emergency stop function. To reduce the stress on the hoist components and the supporting structure to which the hoist is attached during an emergency stop triggered by safety devices, such as brakes, a damper is provided between a component that rests against the supporting structure according to the prior art and the supporting structure itself.