Fig. 2644.
In [Figs. 2643] and [2644] are represented the Otis self-oiling loose pulley, designed to automatically oil itself upon its starting or stopping.
The hub d is cored out in such manner as to form within it an annular chamber or cavity b b, entirely surrounding the bore, and serving as a reservoir to contain oil or other lubricating liquid.
This chamber or reservoir has no direct communication with the bore of the hub, but a communication is formed between it and the bore through one or more chambers c c, which are termed supply chambers, and which are partitioned off within the bore from the reservoir b, by coring the hub in a suitable manner.
These supply chambers have openings n n in their sides or ends communicating with the reservoir b, and also openings c c communicating with the bore of the pulley. These supply chambers are filled with wick or other fibrous or capillary material, which is also inserted into the openings n n, to draw the oil from the reservoir by capillary attraction and supply it in moderate quantities between the bore of the pulley and the shaft on which it runs. Three or more openings are provided in the outer shell of the hub for the introduction of oil into the reservoir b, which openings are closed by thumb-screws, plugs, or other stoppers e e. There being three of these openings, one will always be at or near the top when the pulley is at rest, and through this the oil may be introduced without difficulty. It is not intended that the reservoir should at any time contain more than one-third its capacity of oil, so that whenever the pulley is at rest the surface of the oil will be below the lowest point of the bore, thus preventing any waste of oil at such times.
When the pulley is in motion, the centrifugal force imparted to the oil in the reservoir throws it outwardly, causing it to be distributed in an even layer against the inner surface of the shell which encloses and forms the reservoir, thus preventing any possible waste when the pulley is in motion.
But when the pulley is either stopped or started, the oil is caused to change its position, and in so doing is brought into contact with the wicks protruding from the small openings n n, by which it is conveyed into the supply chamber, and thence to the shaft. By thus taking advantage of what is a necessity in all business establishments in which machinery is employed—to wit, the stopping and starting of the machinery at regular intervals—to insure the supplying, at such times, of a small quantity of oil to the bearings of the loose pulleys, the makers claim that a perfect and reliable means is obtained for guarding against any needless waste of the lubricant.