GB531921A - Improvements in or relating to speed changing gear - Google Patents

Abstract

531,921. Variable speed gearing. PITTER, W. C. July 21, 1939, No. 21234. [Class 80 (ii)] Relates to speed changing gear of the kind described in Specification 242,378, [Class 80 (ii)], in which planetary pinions 15 gear with a fixed sun wheel 22, and are driven through a one-way clutch from an oscillatory crank 38 the throw of which can be varied and in which the planet carrier 17 forms the driven member. According to the invention the gear is provided with variable throw mechanism including a plurality of discs 18 ... 21 on the driving shaft which passes straight through the discs, one, 18, of which forms a variable throw eccentric. As shown, the discs 18, 19 are eccentrically mounted 180 degrees out of phase and are pivoted on pins 26, 27, fixed at diametrically opposed positions on disc 20 fixed to shaft 13. Diametrically opposite pins 28, 29 on the disc 21 engage slots 28d, 29b in the discs 18, 19 respectively so that relative angular movement between the disc 21 and the shaft 13 will vary the eccentricity of the discs 18, 19 in opposite directions. The discs 19, 20 are slotted to allow a clearance passage for the pin 28. Mounted on the disc 18 on rollers 35 is a ring 34 having an annular groove 36 in which work slippers 37 mounted on the crank pins 38a of the cranks 38. A disc 40 to balance the ring 34 is mounted on the disc 19. The disc 21 is fixed to a sleeve 25 pinned at 62 to a drive shaft 13a. The shaft 13 is driven from the sleeve 25 by pins 66. The latter are carried on a sleeve 67 slidable on the sleeve 25 and pass through helical slots 65 in the sleeve 25 and are fixed to a nut 59. This is helically splined to the shaft 13. A handwheel 74 has screwed engagement with a non-rotatable thrust ring 68. Upon rotation of the handwheel 74 the sleeve 67 is slid along the shaft and relative angular displacement of the sleeve 25 and shaft 13 occurs producing change in the throw of the eccentric discs 18, 19. In a modification, axial movement of the thrust ring 68 is produced by a pair of screwed rods which are geared together and one of which is manually rotated by helical gearing.