Electric wire rope hoist with upper camber cause analysis

To ensure the bridge  wire rope hoist  the load when the normal operation of the bridge wire rope hoist manufacturing conditions provides:
No load, the main beam should L/1000 camber (L is the span);
When reaching the maximum permissible load under the main beam deflection should not exceed L/700.
In this range of camber and deflection, bridge  hoist and trolley  an maintain normal operation, so the bridge  Rope hoist  double beam or single beam at the time of manufacture must have L/1000 camber.