Patent GB-697313-A (GB)
Title: Improvements in or relating to internal combustion engines
Inventor: PULLIN CYRIL GEORGE
IPC: F02B61/02
Filed: 1949-10-07
Abstract: 697,313. Silencing exhaust; two-stroke engine construction and cooling ; driving gear; valves; igniting; starting. HERCULES CYCLE & MOTOR CO., Ltd. Sept. 28, 1950 [Oct. 7, 1949; Oct. 31, 1949], Nos. 25809/49 and 27872/49. Classes 7 (ii), 7 (iv), 7 (v) and 7 (vi) [Also in Group XXXIV] In a single-cylinder twostroke crankcase compression engine having a stationary crankshaft and a rotary crankcase and cylinder, the combustible mixture enters the crankcase through a bore in the crankshaft under the control of an apertured rotary disk unitary with, or in driving connection with, the big end of the connecting rod. In the drawings the engine is mounted inside a rotary casing 96 forming the hub of a power wheel for a pedal cycle, the stationary shaft 20 forming the spindle of the wheel and having flats 95 fitting in the spindle-receiving slots of a pedal cycle wheel fork. The crankcase 25, to which the cylinder 26 and cylinder head 67 are bolted by tie bolts 187, Fig. 3, rotates on bearings 24 and the connecting rod 28 is extended at 29 to form a counterpoise to which a valve disc 33, having an aperture 78 controlling the entry of combustible mixture into the crankcase from the hollow shaft 20, is keyed by a projection 79, Fig. 4. The disc 33 is pressed against the crank cheek 22 by springs. The hub casing 96, screwed at 99 for the attachment of a chain sprocket for pedal propulsion, rotates on bearings 100, 102 and is connected to the crankcase 25 through reduction gearing comprising a gear 103 on the crankcase meshing with a gear 125 connectible by a clutch 133, to a coaxial pinion 128 meshing with a gear 104 on the case 96. The gears 125, 128, are carried by a stationary plate 121.. A petroil combustible mixture is supplied by a carburetter connected to the shaft 20 and the exhaust gases containing lubricant pass to a pair of silencers 109 in which the lubricant is separated by centrifuging and blown through nozzles 113 into a channel 114 in the casing 96. from which it. flows into a collecting groove 123 in plate 121 and through an orifice 183 to lubricate the gears 125, 128. The rotary motion of the cylinder causes a stream of cooling air entering through holes 106 in casing 96 to flow radially to outlet holes 105. The ignition system comprises a spark plug 68 and a magneto consisting of a stationary magnet 107 and rotating pole pieces 40 connected to the iron core of an induction coil 41 which is fastened to the crankcase by a spider 38 and acts as a counterweight for the cylinder. A spring-loaded contact breaker 83 on the crankcase in the primary of the coil 41 is actuated by a stationary cam 82. A decompression valve 73 in the cylinder head, Fig. 2, is urged open towards a stop 75 by a spring 74 and is closed by centrifugal force when the engine cylinder rotational speed reaches a predetermined value. The passage 72 leading from the valve 73 is connected by a pipe 112, Fig. 3, to a silencer 109. The engine may also be used as a starter motor for large engines. Specifications 697,383 and 697,384 are referred to.