GB867964A - Improvements relating to gear cutting machines - Google Patents

Abstract

867,964. Gear-cutting. GLEASON WORKS. Dec. 18, 1959 [Dec. 19, 1958], No. 43107/59. Class 83 (3). A gear-cutting machine comprises a slide 65, Fig. 4, reciprocable on a tool head 54, a tool carrier 61 pivoted to the slide and a crank 58 for causing swinging motion of the carrier about an axis perpendicular to the direction of reciprocation, the slide being reciprocated in time with the rotation of the crank. A gearblank G, Fig. 1, is mounted on a head 15 adjustable in the direction of the blank axis 14 on a base 16 swinging on a slide 17 about an axis 18 intersecting the axis 14 and the toolcradle axis 12. The slide 17 is adjustable in the direction of the axis 12. A motor 19, Fig. 2, rotates the work-spindle 13 and oscillates the cradle 11 through rate-of-roll change gears 22, a cam 28, a bell-crank 29 and a connecting rod 31, the movement of the cradle during cutting being in a constant proportion to that of shafts 24, 27 but being faster and at a varying rate during a return roll. A cam 32 moves the work to-and-from cutting position. Index change gears 38 in the drive to the work-spindle cause the blank to be rotated one or more teeth between the cutting operations. The planing tools T, T<SP>1</SP> are reciprocated by a motor 42 through a shaft 45, coaxial with the cradle, and shafts 53. Each tool is clamped by a screw 50, Fig. 3, to a tool-carrier 61 oscillated about a pivot 63 by a crank-pin 58 on the shaft 53. The pivot 63 is carried on the slide 65 reciprocated by cams 68, 69 on the shaft 53 engaging followers 71, 72 on the slide. The crank thus effects the cutting stroke and the cams effect the relief movements. The resultant motion of the tool tip is a path P, p<SP>1</SP> which approximates over the cutting section to the circular path of a milling-cutter blade rotating about the axis 64 of the pivot 63. The slide 65 reciprocates in a direction making an angle with the cradle axis approximately equal to the complement of the pressure angle. If the angle is exactly equal to the effective pressure angle of the sidecutting edge E, the teeth cut are straight. Otherwise, the edge E describes a shallow conical surface and the teeth are crowned. To vary the direction of the path P, p<SP>1</SP> the slideways 66 carrying the slide 65 are adjusted angularly against a vernier 78 and a scale 77. The length of the path P, P<SP>1</SP> may be adjusted by varying the eccentricity of the crank-pin 58 through a clutch 79 and dial 85, at the same time re-adjusting the phase relationship of the cams 68, 69 snd the crank-pin by means of a dial 88 and a clutch 89. The tool mechanisms are carried in heads 54 which are angularly adjustable, the phase relationship between the tools then being adjusted by a dial 91 and a clutch 92. Reference has been directed by the Comptroller to Specification 778,476.