GB539750A - Improvements in or relating to valve mechanism for internal combustion engines - Google Patents

Abstract

539,750. Valve gear; regulating; starting. HARPER, W. March 26, 1940, No. 5469. Convention date, March 27, 1939. Addition to 528,170. [Classes 7 (v) and 7 (vi)] In engines having high-pressure exhaust valves E3 which. are opened in advance of low-pressure exhaust valves F4, F4<1> by cam mechanism, as claimed in the parent Specification, adjustable connections are provided between the cams and the rockers actuating the valves, and means are also provided for facilitating starting. The valves are actuated by a face cam 41 having an inner set of projections which actuate the valves E3 through tappets E45 having adjustable members E48 engaging rockers E49 bearing on the valves through levers E60. An outer set of cam projections then actuate the valves F4 through other tappets connected by knuckles 47 'and adjustable pieces F48 mounted in the ends of a pair of rockers F49 engaging the valves F4, further knuckles . 47<1> being connected by adjustable pieces F48<1> to the forked end of a rocker F49<1> engaging the valve F4<1>, and also to the forked end of a rocker D49 actuating the valve D5 admitting air to the combustion chamber D1. The forked rocker F49<1> is allowed a slight sideways movement by being connected by a pin F53<1> and slot F52<1> to an outer sleeve F54<1>. The cams of a pair of cylinders are driven by worm gearing from shafts 30 geared by bevel wheels to shafts 33, 33<1>, Fig. 12, driven by bevel gearing 34 from a shaft A6, which is geared to the main shaft 14 and also to shafts A8 of rotary valves controlling the inlet of air from a rotary blower to the crank case. The shaft 33<1> has a pair of gear wheels 35 interposed, so that the directions of rotation of the pair of shafts 30 will be the same. Further rotary valves E6, which control the passage of the exhaust either to a conduit E1 leading to the crank case, or to an atmospheric outlet E4, are driven from the shafts 30 through gearing comprising a pair of elliptical gears E11, E11<1>, which give a varying speed to the valves. To facilitate starting, the exhaust valve F4<1> is lifted to relieve compression, by means of a handle on a stem F65<1> connected by a link F64<1> to a cam F66<1>, which forces a plunger F63<1> into engagement with a finger F62<1> on the rocker F49<1>. Also compressed air is forced through check valves 69 into those cylinders whose pistons are in. position to make a power stroke, the flow of air to the appropriate cylinders being controlled by valves 85, Fig. 6, actuated by a solenoid 76 which admits or releases air pressure to or from a piston 84. The construction and operation of the engine are as described in Specification 524,092.