Block and tackle sheave to change the direction of the pulling line, which increases friction losses without improving the velocity ratio. Situations in which reeving to disadvantage may be more desirable include lifting from a fixed point overhead; the additional pulley allows pulling downwards instead of upwards so that the weight of the lifter can offset the weight of the load. The formula used to find the effort required to raise a given weight using a block and fall: where formula_3 is the force applied to the hauling part of the line (the input force), formula_4 is the weight of the load (the
Wire rope spooling technology rope smoothly onto the drum. Level winders can be hydraulically or electrically driven and computer controlled, or they can be simple mechanical devices. A mechanical level winder comprises a main shaft (the lead screw) with helical screw grooving along which the rope feeder travels. The rope feeder housing includes two vertical roller bars and one horizontal roller, or alternatively a wire rope sheave. The lateral movement of the housing is generated by a chain drive sprocket ratio between drum and lead screw, as shown in the image. The automatic level winder fitted is designed and engineered to be compatible with