Active Motor Locking for Crane Drive Trains
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Solution Overview
Problem
Existing lifting mechanism drive trains face issues with transmission damage due to high load peaks and over-braking during emergency situations, particularly in crane lifting mechanisms with frequent shutdowns and high speeds, caused by the operation of both operating and safety braking circuits.
Innovation Solution
The implementation of active motor locking means to hold loads at zero speed, eliminating the need for passive operating brakes, and integrating a freewheel overrun shutdown within the reduction transmission to manage braking during power failures or transmission breakdowns, allowing safety brakes to handle braking operations exclusively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both operating brakes and safety brakes are operated in emergency situations, then the load can be stopped within predetermined parameters, but high load peaks occur in the reduction transmission causing transmission damage
Solution Approach 1:
The invention extracts the function of holding the load at zero speed from the safety brake and assigns it to a dedicated motor locking means. This separation allows the safety brake to be used exclusively for emergency braking operations, preventing it from being stressed by frequent switching cycles while maintaining reliable braking capability when needed.
Solution Approach 2:
The braking function is segmented into two independent systems: motor locking means for normal zero-speed holding and safety brakes for emergency stopping. This segmentation eliminates the conflict between frequent operational braking and emergency braking requirements, preventing transmission damage from high load peaks.
2Reliability
If safety brakes are used to hold the load at zero speed in normal operation, then the load can be securely held, but the safety brakes are subjected to high switching cycles causing premature wear
Solution Approach 1:
The invention extracts the load-holding function from the safety brake and assigns it to a dedicated motor locking means. The safety brake is reserved exclusively for emergency braking operations, eliminating frequent switching cycles and extending its service life while maintaining reliable load holding capability through the motor locking means.
3Device complexity
If passive operating brakes are used to hold the load, then the system is simple in structure, but the brakes cannot actively control the locking timing causing over-braking effects
Solution Approach 1:
The invention replaces passive mechanical operating brakes with active motor locking means that can be precisely controlled through electrical signals. This substitution enables accurate timing control of the locking action, eliminating over-braking effects while maintaining system simplicity through the use of modern electro-mechanical components.
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
This solution reduces transmission damage, minimizes over-braking effects, and extends the service life of crane lifting mechanisms by enabling the safety brakes to handle braking operations without stressing them with high switching cycles, ensuring reliable and secure operation.
Implementation Method 1
at least one active motor locking means for holding the load when the drive motor is decelerated electrically to a rotary speed '0'
Implementation Method 2
The motor locking means are preferably of a positively locking configuration
Implementation Method 3
an automatic overrun shutdown means, preferably in the form of a freewheel
Implementation Method 4
at least one safety brake... in the form of spring-closing brakes which open hydraulically, pneumatically, magnetically or electro-hydraulically
Implementation Method 5
a reduction transmission arranged between the drive motor and the cable drum
Data Source
AI summary
A system arrangement for the drive train of lifting mechanisms, such as crane lifting mechanisms, is disclosed. The system arrangement includes at least one drive motor (1, 1′), at least one cable drum (2, 2′) connected thereto, a reduction transmission (3) arranged between the drive motor (1, 1′) and the cable drum (2, 2′), an automatic overrun shutdown freewheel (6), and at least one safety brake (4, 4′). To optimize such a drive train, at least one active motor locking assembly (5, 5′) is utilized to hold the load when the drive motor (1, 1′) is decelerated electrically to a rotary speed of zero. The active motor locking assembly is utilized instead of at least one passive operating brake.