GB406191A - Improvements in and relating to means for reversing combustion-product engines - Google Patents

Abstract

406,191. Combustion-product engines. KINGSTON, J. R., and POWELL, W. H., Engineer-in-Chief's Department, General Post Office, London. July 11, 1933, No. 19636. [Class 7 (i).] In an engine of the type referred to in Specification 246,692,[Class 7(i),] the inlet and exhaust valves 1, 2 are operated through levers 5, 6 from cams on one or more shafts 3, 4 shiftable for reversing, means being also provided for varying the lift of the valves for controlling the speed and for rendering the cams inoperative before changing the direction of rotation of the engine. As shown, the levers 5, 6 are eccentrically mount - ed on movable fulcrums 7, 8 adjusted by a worm gear, which may also be used for regulating the lift of the valves to control the speed. The valves may alternatively be lifted by wedges actuated from a rock-shaft as described in the Specification referred to. The inlet-valve cams are stepped, the starting portion 11 giving a late cut-off of about three quarters of the piston stroke and the running portion 12 giving a cut-off of about a quarter stroke. The cam shafts are shifted axially by a hand lever or by compressed air, the reversing lever and the means for lifting the valve levers being interlocked in the latter case. In a modification, Fig. 4, the ahead and astern inlet cams 19, 20 are tapered to allow a small lift with late cut-off for starting, increasing gradually to full lift with early cut-off for normal running, enabling the whole manoeuvring operation to be effected by a single shift lever ; and the cams are such that shifting of the cam shaft will render them inoperative before changing the direction of rotation of the engine.