GB480720A - Improvements in methods of lapping toothed gears - Google Patents

Abstract

480,720. Lapping gear-wheels. TENNANT. W. J. (Carborundum Co.) Aug. 29, 1936, No. 23717. [Class 60] A toothed gear-wheel is lapped, by rotation in engagement with one or more toothed members each mounted on an axis inclined to that of a normally mating gear and in a plane containing the axis of the lapped gear, the lapping teeth being so formed as to sweep over the whole working faces of the gear teeth and to provide rolling contact on a line which is oblique to the normal line of rolling contact with a mated gear. Fig. 1 shows a toothed gear 40 mounted on a mandrel 37 between centres 28, 35 on a sliding carriage 22 and meshing with lapping members 49, 49a which may be adjusted to the same or different angles relatively to the toothed gear on swivels 41, 41a adjustable about vertical axes on a base 20. The member 49 is driven by a belt 53 for alternate periods in opposite directions, the pressure between the gear and lapping members being regulated by means of an adjustable brake band 55 on the shaft of the member 49a. During these periods the carriage 22 is reciprocated on the base 20 by a lever 24 so that the lines 60, 63<1>, Fig. 14, of rolling contact, which are inclined to the normal lines 58 of contact with a mated gear, move along the surfaces of the teeth. The lapping members are preferably constructed of bonded abrasive material but, alternatively, metal members supplied with powdered abrasive in an oil vehicle may be used. The gears to be lapped may be of the spur, helical, herring bone or multiple gear type, either internally or externally toothed.