Electric hoist crane safety devices

 Electric  lift hoist  crane because of its simple structure, easy operation, low cost, machinery, chemicals, light industry, railways and other industries widely used. Because of this special cranes, ground operations often a person several roles, and also served as operations, company search, command tasks, there are many unsafe operating risks.
       In order to prevent the occurrence of this type of crane lifting injuries, GB6067-1985 "crane safety regulations" and other relevant national standards have to be electric hoist crane must have safety devices, such as limit switch, end stop, bumpers, safety braking devices. These security guards equipped to effectively improve the safety and reliability of electric hoist crane, but because of the design, manufacturing defect itself a variety of reasons, the current electric hoist crane inadequate security measures, according to the daily inspection experience found hoist crane in the wrong phase-phase protection, anti-broken shaft protection against electric  manual hoist  fall protection, buffer settings, etc. are still flawed or inadequate.
       Since using the three-phase asynchronous electric hoist crane conical brake motor as power plant, while the three-phase asynchronous motor rotation direction and the power supply phase sequence, and when the power supply phase sequence is changed, the motor rotation direction and the direction of the original operation Instead, press "down" button, spreader rise, and rise to the limit position limiter does not work, likely to cause accidents. Every year, this type of crane caused due to wrong phase crushed reel, hook group extrusion, wire rope pull off the accident. At present, China produced and widely used CD, MD electric hoist did not take the wrong phase-phase protection measures. To prevent the wrong phase injury accidents caused by lifting,wire rope winch electric hoist crane electrical control system added wrong phase-phase protection.