Compact Control Device for Fail-Safe Brake Actuation
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Solution Overview
Problem
Existing safety brake control systems for elevators and similar applications require complex and redundant setups to ensure fail-safe operation, including contactors and safety controllers, which complicate the control of high control currents and monitoring of brake states, leading to potential safety issues and increased complexity.
Innovation Solution
A compact control device that integrates power switching elements and an evaluation unit to manage high control currents and monitor brake states, replacing traditional contactors and simplifying the control process by providing logical control and status signals, thereby reducing the burden on higher-level controllers and enhancing fail-safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If contactors are used to switch control current for safety brake, then high control current can be switched, but device complexity increases and safety monitoring becomes more difficult
Solution Approach 1:
The patent combines the power switching function and safety monitoring function into a single integrated control device. The control device includes power switching elements for switching the control current and an evaluation unit for safety monitoring, eliminating the need for separate contactors and simplifying the overall control system while maintaining both high power capability and safety functionality.
Solution Approach 2:
The control device performs multiple functions simultaneously: it switches the high control current to the electromagnet, monitors the brake status via microswitch, detects faults in control lines, and provides safety monitoring outputs. This multi-functional integration replaces the traditional separate contactor and safety controller setup.
2Reliability
If redundant safety controllers are used for fail-safe operation, then safety reliability improves, but device complexity and installation effort increase
Solution Approach 1:
The patent integrates safety monitoring functions directly into the control device itself. The evaluation unit monitors control line faults, electromagnet status, and brake microswitch signals, providing fail-safe operation without requiring a separate redundant safety controller. This integration maintains SIL 3 safety level while reducing system complexity.
Solution Approach 2:
The control device acts as an intermediary between the higher-level controller and the brake components. It receives control signals, switches the high current, monitors safety parameters, and communicates status back to the higher-level controller, thereby simplifying the overall control architecture while maintaining safety.
3Reliability
If microswitch monitoring is added to detect brake status, then safety monitoring capability improves, but device complexity increases
Solution Approach 1:
The evaluation unit integrates multiple monitoring functions including microswitch status detection, control line fault detection, and electromagnet current monitoring into a single unified safety monitoring system. This consolidation provides comprehensive brake status monitoring without requiring separate monitoring devices for each parameter.
4Power
If contactors are used for control current switching, then high power switching is achieved, but wiring complexity and installation effort increase
Solution Approach 1:
The control device integrates the power switching elements and control circuitry into a single compact unit, eliminating the need for separate contactors and their associated wiring. This integration significantly reduces wiring complexity and installation effort while maintaining the capability to switch high control currents required for safety brake operation.
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 compact control device ensures reliable and fail-safe activation and deactivation of safety brakes, simplifies installation and commissioning, and reduces wiring complexity, while providing flexible control options for different operating scenarios, thus enhancing safety and cost-effectiveness.
Implementation Method 1
an electromagnet must be excited with a control current in such a way that the anchor plates are pulled away from the rotor due to the magnetic force
Implementation Method 2
As soon as the current is interrupted, the anchor plates press against the rotor again due to the spring force
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a compact control device (12) for the failsafe actuation of an electric actuator (16, 18) which can move a displaceable machine part into a defined end position and which has a first input connection (40) for receiving a first external control signal (36). The first external control signal (36) sets a desired position of the machine part. The compact control device (12) also has an input part for detecting a position signal (68) which signals an actual position of the machine part at the defined end position. A power part comprising at least one power switching element (24) is designed in order to switch on and switch off a control current (32) for the actuator (16, 18) in a failsafe manner. The control current (32) is guided via a first output connection (54, 56) to the electric actuator (16, 18). The compact control device (12) has a second output connection (60) in order to provide an external status signal (34) and has an evaluation unit (22) which actuates the at least one power switching element (24) on the basis of the first external control switch (36) and generates the external status signal (34) at the second output connection (60) on the basis of the position signal (68).