Poor working conditions, control of overhead crane accident

Some of metallurgical enterprises, mining enterprises, machinery manufacturing enterprises,  hoist gantry crane  operating environment is very harsh. As smoke from various smelting furnace; various pneumatic, electrical machinery, machinery roar; addition of sand, hit the dust and noise venue box; annealing, water blasting operation, water vapor, etc., tend to make the day truck drivers operating in a inaudible, invisible harsh environments. In this condition occurs, "roll over" accident, the accident has happened often, resulting in serious consequences, the driver can be aware of. In order to prevent "over volume" accidents, the best solution is to install limit alarm device. I had a few years ago where the business case in the fight, water blasting site running 17 # day vehicles designed and installed such devices. Detailed control over volume process that  Steel crane  in operation, when the hook set up, once the carom limit cross-foot (regardless of what causes "roll over", hooks groups are bound to the first strike against the corresponding horizontal ruler or other limit switches normally closed off within an indirect action part), horizontal ruler starts at the limit lifted, resulting in limit switch normally closed off at the same time, with linkage alarm device for closing the normally open points, electric horn sounded, drivers will inevitably perceive, immediately take emergency control measures, you can avoid the "roll over" accidents. The car previously occurred almost every year "over volume" accident, since the installation of such a warning device, has been unharmed. Such other types of alarm limits appropriately improved control system, can be used, and in the non-concentrated smoke, loud noise  gantry crane  working environment is also necessary to install an alarm device in order to achieve safety. Limit alarm device schematic diagram Note: This circuit can protect the disk from the main circuit over current relay coil bottom to take power, but also through the volume lighting, bells take power with isolation transformer. Small power electric horn or bell installed in the cab, you can use motorcycle suspension cables or spare power supply cable line two. Limit switch with L × 10-31 type limit switch, which is still connected normally closed limit circuit, normally open alarm circuit connection.