Rope Drive

—The transmi ion of power by means of rope gearing, the ropes being of either hemp or cotton, varying in diameter from ł” to 2”. The speed of ropes ‘is from 3000 to 7000 feet per minute, 4500 being the average. The pulleys are usually of cast iron, the grooves on their surfaces being from 37° to 45°, the latter being the most common angle. Joints are made by splicing, the splice being 15 diameters in length, while the pulley should not be le than 30 times the diameter of the rope. Two plans are in use, one with independent ropes, suitable for transmitting power from an engine to numerous lines of shafting; the other, where only one rope is used, pa ing around all the grooves in turn and being kept taut by a tightener or jockey pulley, this last is very useful for drives at awkward angles or supplying power in series to a number of small units. With either plan the lower side should always be the driving side, and with the independent rope drive, a good horizontal sag should be given.