GB862153A - Tooth profile checking apparatus - Google Patents

Abstract

862,153. Gauging toothed gears. ILLINOIS TOOL WORKS. Feb. 7, 1957, No. 4270/57. Class 106 (2). [Also in Group XXII] An apparatus for checking tooth profiles of circular toothed workpieces 130 includes a checking member 94 mounted for combined rotation and radial motion with respect to a centre spaced from the centre of the workpiece 130, and means 26 for imparting to the member 94, radial motion of less magnitude than the circumferential motion due to rotation, for causing the member 94 to define substantially the theoretical profile of the tooth being checked. A carriage 14 is slidably mounted on the base 12 and may be adjusted by a hand wheel 22, and locked by a screw 24. Fixed to the carriage 14 is a master cam 26 and a shaft 28 on which is pivoted a head 30. On an extension 34 of the head 30 is a slide 36 urged by a tension spring 40 against a lever 56, 52. The lower arm 52 of this lever carries a roller 54 acting on the cam 26 and the upper arm 56 has a vertically adjustable abutment 60 cooperating with the slide 36. Thus the ratio A/L (see Fig. 1), may be varied. The slide 36 carries a further slide 72 which may be adjusted longitudinally of the slide 36 by a hand wheel 78. Attached to the slide 72 is a pillar 84 on which is fitted a shaft 90 carrying the checking member 94 which is adjustable and a fixed finger 98 engaging with a dial indicator 100, which also actuates a recording mechanism driven in accordance with the rotation of the head 30. In operation, the gear 130 is placed on a shaft 16, and the carriage 14 is adjusted to locate the shaft 28 a predetermined distance from the shaft 16. The upper slide 72 is then adjusted to position the tip 94 of the checking member a predetermined distance from the shaft 28, and the arm 56 of the lever adjusted so that the ratio A/L equals a predetermined value. The head 30 is then turned by a hand wheel, and the action of the cam 26 in displacing the slide 36 and hence the tip 94 radially combined with the circular motion of the tip about the shaft 28 makes the tip follow the theoretical curve of the gear teeth, inaccuracies in the shape of which are shown by the dial indicator 100. A mathematical discussion is given showing how one cam 26 will serve, by means of the adjustments described above, to test a family of geometrically similar gears, e.g. involute, epicycloid cardioid, &c. To check the other face of a gear tooth, the slide 72 is reversed and the head 30 rotated through 180 degrees, the cam 26 being provided with a similar curve on its opposite face. If desired the carriage 14 and head 30 may be mounted on the base of a known machine such as a hobbing machine.