The Mechanical Handling and Storing of Material

Forfatter: A.-M.Inst.C E., George Frederick Zimmer

År: 1916

Forlag: Crosby Lockwood and Son

Sted: London

Sider: 752

UDK: 621.87 Zim, 621.86 Zim

Being a Treatise on the Handling and Storing of Material such as Grain, Coal, Ore, Timber, Etc., by Automatic or Semi-Automatic Machinery, together with the Various Accessories used in the Manipulation of such Plant

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272 THE MECHANICAL HANDLING OF MATERIAL Fig. 396. Otto Coupling. As soon as one of these knots approaches the coupling it lifts the fangs of the bolt d and slides underneath, its progress being arrested by the fangs of bolt e. The spiral spring replaces the fangs of bolt d, so that the coupling and carrier must now travel with the rope. The hook f is connected with the pawl g, and is for the purpose of un- coupling the carrier. Another construc- tion for the same con- ditions is that of Eiligen shown in Fig. 3 9 5. This consists of the frame b, roller c, and catches d, which latter are the chief features of the coupling. They are arranged on either side of the roller e •, in the illustration these are shown in the lowest position, as they rest upon each other at e, the rods f engage with a short length of rail at the stations and thereby lift the catches, thus uncoupling the rope as shown in the lower picture. The uncoupling process is similar to that of the previously described appliance. Owing to the insecurity of some of the knots on the rope, and the great wear on both sides of the knots caused by these couplings, it was realised that their em- ployment did not solve the difficulty in the best and most economical way, and further efforts were made to design such a coupling as would give sufficient grip for steep inclines and heavy loads without the use of knotted ropes. Theodore Otto abandoned the eccen- tric principle for these couplings in 1877 and introduced a gripping device on the screw-vice principle. It would occupy too much space here to explain why this screw device was not introduced before, but the chief difficulty was that a certain clearance between the gripping device and the rope was always necessary; and to close the jaws when sufficiently far apart until a sufficient grip was obtained, the coupling lever would have to traverse a larger segment of a circle for a screw device than for an eccentric device (the latter takes less than 90°), and if so short a movement of the tightening lever is chosen for a screw device, the pitch of the screw has to be so steep that there is a danger of its coming undone through