The Mechanical Handling and Storing of Material

EO PE WAYS 2~jl also depends solely on the friction between rope and eccentric. The appliance, Fig. 393, was a further step in this direction by the same firm. It consists of a roller a, and a segment of an eccentric b, which is movable around a pin c, this pin couples the eccentric to an extension d, which is guided in a cast-iron bracket where it can move up and down; this extension d can be manipulated by a second eccentric e. To the axle of this second eccentric is fixed a lever f provided with a handle, and it will be seen that by the movement of this handle the eccentric b is pushed down upon the rope in that position as shown in the drawing. The rope is gripped by the eccentric b, but the eccentric motion, or grip of eccentric e, has not yet come into force, and this will give an auxiliary grip when the rope pulls in either direction. This apparatus is quite satis- factory for ropeways which negotiate moderate inclines and for moderate loads. More modern installations, with inclines exceeding 1 in 3 and heavier loads, require a coupling of still greater gripping power. Experts realised the difficulty of such a design, and therefore adopted the expedient of a rope with knots as an easy way out of the difficulty. These knots were attached in a variety of ways to the rope at fixed intervals, each knot engaging with the coupling of one of the carriers, and this had the advantage of dis- tributing the load uniformly over the rope, but it had the drawback over the previous method of attaching the loads promiscuously, in that the capacity of the ropeway cannot so easily be altered. It is not here intended to describe at length the various methods of attaching the knots to the rope; they were either securely attached to the strands of the rope and thereby made fast, which, as we shall sdte later, was not found a good plan, or they were made movable so that they could be taken off and fixed in a fresh position. They also had the advantage of being attached quickly and easily, but they lacked security in their position and were apt to shift. A rope thus fitted with knots would not require a gripping device, but rather what is known as a locking grip or coupling, so it was necessary to reconstruct the coupling to accommodate it to these altered con- ditions. The illustration, Fig. 394, shows a design of Adolf Bleichert’s, which consists of a rope roller a and bracket by which carries the sliding block <f, and this carries two bolts or pins d and e, which latter have at their base peculiarly shaped fangs or claws. The bolt d admits of a vertical movement and is held in its normal position by a spiral spring. The method of coupling the carrier to the rope is performed as follows: