WINDLASS, STEAM CAPSTAN, Fig. 1 represents a new form of steam capstan wind lass. manufactured by the American Ship Windlass CO., of Providence. H. I., which has become almost exclusively adopted on American vessels. Among the novel features are the following : The valves of the engines are driven by a straight eccentric, without rocker shafts. There is a steam reverse valve for reversing the windlass in case of jamming of the ropes. The solid center bearing of the main shaft is arranged close to the gearing, so as to prevent any springing of the shaft under sudden strain. It will also be observed that the power is transmitted directly from engine to windlass, with no intermediate gearing. Engine and windlass are connected to one plate, by which the parts are tied together so that they can not get out of line. If the deck above twists or strains, or even is entirely swept away, the windlass can still be efficiently operated by steam. A novel lubricating contrivance, which constantly applies oil to the teeth of the worm gear, and a crank-shaft counterbalance, which balances the weight of the cranks, pistons, and rods, and prevents jerking motion, are added. The general construc tion is simple, strong, and ef fective. A detailed account of the mechanism will be found in the United States patents for the device, granted July 31, 1888, and March 14 and July 2, 18S9.
The Ravelli Windlass, Fig. 2, consists simply of a strong iron frame, of a bevel gearing, whose pinion is keyed to the winch shaft, and of a pair of helicoidal gearings. Upon the shaft that connects the two bevel wheels is keyed a drum, provided with depressions for the reception of the chain to which the load to be lifted is attached. The endless screw has several threads, but the latter
do not, as usual, run around the entire circumference. If there are four threads, each of them covers but a quarter, and if there are six, each embraces but a sixth of the surface.
Upon the whole, this endless screw constitutes a sort of a disk, upon the circumference of which are arranged a variable number of pins that are slightly inclined with respect to the bases of the disk. At every fraction of a revolution corresponding to the number of the pins, one of them abandons the tooth of the gearing while the following pin and tooth engage. In order to diminish passive resistances. the teeth do not rub against the inclined planes formed by the pins, but roll over them. To this effect, they consist of truncated cone spindles loose upon journals set firmly into the felly of the gearing. The wear of these spindles is slow, because they are numerous and engage at relatively wide intervals of time. The power of this machine is very great, although no recourse is had to a differential mechanism nor to tackle. Stoppage is secured under full load, either in the raising or lowering of weights. without the intervention of any stop-work or brake. No flying back of the winch is to be feared, and this gives every security to the workman.
Wire Belting : see Belts.
11'ire-cord quarrying : see Quarrying Machines.
Wire Rope : see Rope-making Machines.