This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...which are used more especially on bevel gears, the difference is not so pronounced Mr. Wilfred Lewis reported, in the Proceedings of the Engineers' Club of Philadelphia, Vol. X, 1893, page 16; also in the American Machinist, May 4, 1893, page 3, certain formulas, for the design of cut spur and bevel gears, which he had ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1909 Excerpt: ...which are used more especially on bevel gears, the difference is not so pronounced Mr. Wilfred Lewis reported, in the Proceedings of the Engineers' Club of Philadelphia, Vol. X, 1893, page 16; also in the American Machinist, May 4, 1893, page 3, certain formulas, for the design of cut spur and bevel gears, which he had deduced to take into account this variation, in strength, due to number of teeth. The scheme for the gear tooth design which he outlined has met with such universal favor and wide spread usage since its introduction that it may almost be referred to as the accepted standard method of design. Mr. Lewis in his investigation assumed the total turning effort to be taken by one tooth and the force, W = P, as being effective at the point in the tooth where the normal to the tooth curve at its upper point intersects the median line of the tooth. At this point the pressure between the teeth is resolved into two components--one perpendicular to the radius of the gear through the point, and the other radial. This radial component is neglected, only the tangential force which exerts a purely bending action on the tooth, being considered. In accordance with these assumptions, substitution was made in formula (39), yielding the expression We need not be concerned with the value of x further than to 2 x say that--= y. This is the factor of strength, varying with the number of teeth; it is determined by graphical construction, and is given in Table XVI, for reference. W Then p = (45) or if b = 3 p as in formula (41), then It should be noticed in the application of formula (45) that either the pinion or the wheel, gearing together, may be the measure of strength of the combination; it therefore becomes necessary to investigate in each case, for the gear with...
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