Revolving Tower Crane Slewing Brake Dynamics
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Solution Overview
Problem
Revolving tower cranes face instability due to auto-rotation under unfavorable wind conditions, as existing brakes struggle to balance alignment with wind direction and prevent excessive rotation, with configurations often failing to adapt to varying wind conditions and crane positions.
Innovation Solution
An electrodynamically configured slewing gear brake using the crane's electric motor as an electric-motor brake, which adapts braking torque based on rotational speed, allowing alignment with wind while preventing dangerous auto-rotation, and featuring a braking resistance system that can be controlled and cooled to ensure efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the slewing gear brake is preloaded into its braking position to ensure stability, then the crane remains stable, but the crane cannot align itself with wind direction in the out-of-operation state
Solution Approach 1:
The brake system transitions from a static preloaded state to a dynamic controllable state. The adjustment actuator enables the brake to move between a first position (braking position for stability) and a second position (release position for wind alignment), allowing the system to adapt its braking characteristic based on operational requirements.
2Stability of the object's composition
If an additional brake is provided to limit rotational speed and prevent auto-rotation, then the crane stability improves, but the device complexity increases
Solution Approach 1:
The existing slewing gear brake is made multi-functional by adding the adjustment actuator. The same brake component serves both as a stability-maintaining device (when in first position) and as a wind-aligned release mechanism (when in second position), eliminating the need for a separate additional brake while still providing auto-rotation prevention.
3Stability of the object's composition
If the brake applies high braking torque to prevent auto-rotation under strong wind, then the crane stability improves, but the crane cannot align itself properly with wind direction under moderate wind conditions
Solution Approach 1:
The braking torque becomes dynamically adjustable through the adjustment actuator. By moving the brake between first and second positions, the system can apply high braking torque when needed for stability and reduce braking torque to allow wind alignment when conditions permit, adapting to varying wind conditions.
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 ensures stable crane alignment with wind direction while preventing auto-rotation, maintaining wear-free operation and avoiding the need for additional mechanical components, with adaptable braking torque that adjusts to changing wind conditions and crane configurations.
Implementation Method 1
use an electric motor of the slewing gear drive, which is used for rotating the crane in normal crane operation, as a slewing gear brake in the shut-down, out-of-operation state, with said slewing gear brake permitting the rotary movements under wind, but braking it
Data Source
AI summary
The present invention relates to a crane, in particular to a revolving tower crane, having a boom rotatable about an upright slewing gear axis by a slewing gear drive and having an out-of-operation brake which allows and brakes rotary movements of the boom in the out-of-operation state. In accordance with the invention, the out-of-operation brake is configured as working electrodynamically and comprises an electric motor of the slewing gear drive which can be operated as an electric-motor brake.