GB396598A - Hydraulically-controlled infinitely-variable transmission mechanism - Google Patents

Abstract

396,598. Variable speed gearing; oscillating -cylinder pumps. STEADMAN, A. H., 23, Haigville Gardens, Ilford, Essex. Dec. 2, 1932, No. 34146. [Class 80 (ii).] Relates to variable-speed gearing comprising epicyclic gearing controlled by pumps pumping oil which is throttled under manual control. The driving-element is a casing 1, Fig. 1, rigid with a primary sun gear 2 loose about a main shaft 4. The driven element is a carrier 44 of bevel planets meshing with side gears 41, 42 of a differential train. Fast on the main shaft 4 is the gear 41 and a revoluble drum 3 forming the carrier of stepped planets 10, 11 meshing respectively with the primary gear 2 and with a secondary sun gear 12. The gear 12, which is larger than the gear 2, is fast on a sleeve 13 to the other end of which is secured the gear 42. When the driven element 44 is at rest, the shaft 4 and sleeve 13, and therefore the drum 3 and sun gear 12, are rotating at equal speeds in opposite directions. The forward variable drive is effected by reducing this relative rotation of the drum 3 and gear 12. To this end, planet gears 15, Fig. 2, meshing with the gear 12 each carry a balanced crank 21 with a bearing shoe 20 secured to the plunger 18, Fig. 4, of a pump 16 which oscillates on trunnions 17 in the drum 3. As the drum 3 turns clockwise of Fig. 2, scoops 40 pile up pressure oil in front of the inlet valves 39 of the pumps. The sectional area of the plunger stem 18, Fig. 4, is half that of the bore of the barrel 16 which is filled by the pump piston 19. Within the piston is a ball valve 36. As the piston descends, a volume of oil equal to that moved through by the piston passes the ball 36 upwards through ports 35. Half is expelled through a channel 22, and half remains around the stem 18 to be expelled on the upward stroke of the piston. The pumps are thus doubleacting, so that oil is delivered centrally through pipes 24 and pressure builds up in an annular chamber 25, Figs. 1 and 3, which resists the action of the pumps. The chamber 25 is closed by a ring of spring-pressed balls 26 which are thrust positively outwards, to relieve the pressure and so to slow down the driven member 44, by sliding manually a sleeve 30, Fig. 1, with a tapered end 31 adapted to engage the balls simultaneously or in succession. The oil escapes by a central chamber 28 into the drum 3. To effect reversed driving, which is wholly mechanical, a brake is applied to a drum 46 rigid with the sleeve 13. The drum 3 turns backwards round the stationary gear 12 carrying the gear 41 with it and the member 44 follows at half speed, the gear 42 being also stationary.