Requirements for control systems of Electro-Hydraulic drum Brakes
Taking into account the crane movements need frequent action, and a little action requirements, if the safety brake is also frequent action, it will affect the movements of the action requirements, therefore, the control system design should meet the following requirements of the working state:
(1) normal working condition. Each time the crane is started, the crane driver presses the start button, the safety brake automatically opens the gate, and the signal is opened to the console to allow the crane to work. During the crane operation, the lifting brake is completed by the working brake, the safety brake to keep the normally open state. Lifting the work of the end of the work brake closing brake, the crane driver to check the same, before leaving the console, cut off the crane power supply, safety brake closing lock, the end of the work;
(2) the working state of the crane when the failure occurred. In the event of failure, the crane driver presses the emergency brake button, the working brake closes the brake immediately, and the safety brake is delayed by 2 ~ 5s to stop the accident.
(3) the working state of the crane when the accident occurred. In the event of an accident, the crane driver presses the emergency brake button, the crane controls the power supply to disconnect, the working brake and the safety brake are immediately shut off the brake, preventing the occurrence of the accident;
(4) In special cases (such as a sudden failure of the crane system), the working brake and the safety brake shall also be subjected to an emergency closing brake at the same time.
Or the safety brake is set to normally open safety brake, usually the safety brake is always fully open state, the crane lift brake work by the work of the brake to complete the safety brake as a protective backup. When the crane fails and the accident or work brake needs to be repaired, the working brake needs to be released to switch the high gear and low gear when the safety brake is put into use.
