MOFFETT ROLLER-BEARINGS.

MOFFETT ROLLER-BEARINGS.

S. B. Thorp, 290 Broadway, Manhattan, New York, reports that he has received orders from all parts to equip fire apparatus with Moffett rollerbearings. These bearings afford great efficiency in the propulsion of all classes of rolling stock, as they save about ninety per cent. of power in starting. As an instance: A piece of apparatus, equipped with Moffett roller-bearings, may be pushed on a smooth floor with one hand, where it would take three horses to move the same machine equipped with only the old style axles. Another advantage is that a run may be made in a much shorter time, probably a reduction to one-half. When once attached to apparatus these bearings require no more care or attention, that is, they require no oiling, and, as they are assembled so finely, and the parts are perfectly fitted, they are as moisture and dustproof as a fine watch. As to their wearing qualities: They have been tested on such high speed machinery as electric motors, and carried such heavy loads as street railway cars and steel gondola freight cars for several years without showing any appreciable wear. One set of bearings was taken from an Omaha, Neb., street car, after the official records showed a total mileage of over 58,000 miles—or a distance equal to more than twice round the earth’s surface, and upon examination no measurable wear was found. The construction of the bearings is given in the report of the test made at the Armour Institute of Technology by Professors C. V. Kerr and A. M. Feldman, as follows: “Upon an axle rotates a cage carrying seven rollers, made of Bessemer steel and casehardened. These are mounted upon a loosely fitted spindle of the same material. The proper alignment of the roller and the end-thrust of the roller are cared for by a ball-bearing at each end, consisting of eight hardened tool steel balls, rolling upon casehardened surfaces. The thrust of the cage is received by a plate of Bessemer steel carrying a brace of balls.” The report continues: “End-thrust, as well as alignment, was provided for by ball-bearings at each end of the rollers. This feature of the design deserves especial mention, as it eliminates almost entirely the sliding friction; in this respect we consider your bearing superior to any design that has ever come under our notice.” From data on the frictional resistance of shafting in mills and factories, and of the mechanical efficiency of engines it appears safe to say that from ten to fifteen per cent, of the total power required to drive mills equipped with babbitt bearings can be saved by roller-bearings, and. by using roller main bearings mi engines, five per cent, of the total indicated horsepower could be saved. This seems a small saving but, in case of a 2,000 horsepower engine, it means too horsepower, or $2,000 at twenty dollars per horsepower per year. During the comparative tests the roller-bearings were not lubricated. The other bearings were copiously lubricated all the time by a saturated felt pad; but there was constant trouble at heavy loads and high speed to prevent undue heating.

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