Two off Dual Rope winches were designed in conjunction with our client for the rapid opening and closing of Blast proof doors in a mining application. Each winch has two ropes, as one rope winds off the other winds on, each rope is connected through a series of sheaves to one end of each door, the winch is reversed to open/shut the doors. In addition the winches are fitted with a manual override crank handle in case of power failure the doors can still be operated.