GB353750A - Improvements in or relating to method of controlling friction ratchet gears and an arrangement therefor - Google Patents

Abstract

353,750. Variable-speed ratchet gearing. AKTIEBOLAGET SPONTAN, 2, Norrmalmstorg, Stockholm. Sept. 4, 1930, No. 26434. Convention date, Sept. 5, 1929. [Classes 80 (ii) and 80 (iii).] In friction ratchet gearing for motor vehicles &c., of the kind wherein the elements at times drive synchronously and at other times intermittently to produce lower speed ratios, as set forth in Specifications 259,975 and 281,983, [both in Class 80 (ii), Gearing, Variable-speed &c.], the initial pressure of the rollers &c. on the gripping surfaces, which, according to Specification 349,010, is increased with increase in the viscosity or pressure of the lubricating oil, is again reduced during synchronous or direct drive, when the oil pressure would normally be high. Fig. 1 shows diagrammatically a gear of the kind described in Specification 281,983, having the cages for the roller-ratchet gear 3 and detent 2 fitted with the pressure-varying means described in Specification 349,010. The oil supply from the pump 4 passes to the devices 2, 3 through channels 5, 7 and, normally, through a narrow passage 8, the pressure-responsive piston 10 acting on the cages through linkage partly shown at 11. The passage 8 can, however, be short-circuited by a large outlet provided when two ports 13, 14 register, these ports being formed respectively in the driving member 12 for the bob-weights 20, 21 and the member 15 carrying the eccentrics 18, 19. When the drive is synchronous, the parts 12, 15 take up a steady relative position with the bob-weights slightly displaced from their outermost positions, the ports 13, 14 then coinciding, as shown in Fig. 2. During'asynchronous running, the ports intermittently open and close, inducing an increased pressure in the oil, which can escape only slowly from the pressure cylinder 9 by leakage past a check valve 23. Fig. 4 shows a practical embodiment, including a damped resilient drive for the member 26 linked to the bobweights 20, 21. The member 26 is connected to the engine shaft through the sleeve 12 and a long yielding shaft 24, oscillations being damped by plugs of compressed cork &c. 29 frictionally engaging a drum 31, which is secured to the engine shaft and may carry a starter spur-gear 30.