GB157890A - Self-braking engine - Google Patents

Abstract

157,890. Reed, G. B. Jan. 7, 1920, [Convention date]. Cam gears; beat or lift valves; rotary and oscillating cylindrical valves; slide valves, piston and flat; value spindles.-An engine is provided with continuous automatic braking means which are brought into play by a hand-controlled lever. During braking, the ordinary exhaust is closed and the normal fluid supply cut off by a rotary valve, and an auxiliary fluid supply to the cylinder C controlled by the piston at the end of the forward stroke is compressed during the return stroke until the pressure is sufficient to force the inlet valve off its seat whereupon it exhausts through a passage controlled by the rotary-valve. In the construction shown in Fig. 1, the inlet and exhaust are controlled bv the lift valves A, E operated by a pair of longitudinally adjustable cam shafts m, y controlled by a hand-lever i<2>, Fig. 2<a>. The cams operate the valves by levers; the lever operating the exhaust valve is adjustably mounted upon an eccentric s, Fig. 2<c>. To the spindle of the inlet valve A is secured an auxiliary spring-pressed piston B which is open to the atmosphere below and also above during normal working, but during braking is pressed down by the supply fluid. The fluid supply of the engine is controlled by a throttle-valve T, and a rotary valve F which also controls the exhaust and the auxiliary supply to the piston B and cylinder C. The valves T, F and eccentric s are simultaneously operated by a lever D, Fig. 2, which may also control a valve in the cylinder auxiliary supply for braking. During normal running, fluid passes through passages z, k<1>, n<1> in the valve F, o<1> to the cylinder, and exhausts through passages p<1>, q' in the valve F, r<1>. The cylinder C, and top of piston B are put into communication with the exhaust by auxiliary connections u<1>, s'. During braking, the valve F closes the passage p<1> and puts the passages k<1>, s<1>, o<1>, r<1> into communication as shown, and the eccentric s is adjusted to keep the valve E closed. A modification is described wherein a lift inlet valve is applied to a uni-flow engine. The engines with lift valve may be double-acting. Modifications of the braking-means adapted to uniflow and reverse-flow engines having flat and piston slide valves are described. In the case of engines with flat slide valves, the valves, during braking, are held to their seats by auxiliary pistons having balls or rollers engaging the back of the valves. To permit yielding under compression during braking, a flat valve is made in two parts hinged together, the valve-rod being pivoted to the hinge spindles. The invention is applicable to engines with Corliss and rotary valves, and to multiple-cylinder engines.