GB247391A - - Google Patents

Abstract

247,391. Rushworth, W. Feb. 18,1925. Two-stroke engines. - The charge compressed in the crank case is transferred to the combustion chamber through a valve 17 in the piston opened by the angular movement of the connecting-rod. A tappet 23 mounted on the gudgeon pin 21 has projections 24 engaged by abutments on the small end of the connecting-rod, and another projection 25 engaging a lug 34 on a valve rocker 30. The arrangement is such that, as the connecting- rod swings outwards on the down-stroke of the piston, bevelled surfaces on the projections 25 and 34 slip past each other without opening the valve, the tappet 23 moving axially against a spring to allow of this, while as the connecting-rod swings back to its central position during the lower part of the stroke, the projections 25 and 34 so-operate to open the valve, which becomes again closed at the bottom deadcentre. The rocker 30 is weighted at 31 to provent the valve from opening against the action of its spring when the movement of the piston is reversed at the end of its stroke. Combustion chamber, shape of.-The cylinder head is formed with curved portions 10 extending outwards from a central projection 8, so that the charge entering through the valves 17 and imping- ing on the projection 8 is then directed outwards along the curved portions 10 and down the cylinder walls so as to scavenge the 'burnt gases.