GB430425A - Improvements in hydraulically operated valve gears for engines with reciprocating pistons - Google Patents

Abstract

430,425. Valve gear ; reversing. WERKSPOOR NAAMLOOZE VENNOOTSCHAP, 62, Oostenburgermiddenstraat, Amsterdam, and MATTERN, H. M. M., 10, Diependaalsche Drift, Hilversum, both in Holland. Dec. 18, 1933, No. 35550. [Classes 7 (v) and 7 (vi)] [See also Groups XXVI and XXVIII] Comprises a hydraulic valve gear wherein mechanically - operated pistons working in a common cylindrical block operate the distributing- valves of an engine through pistons associated therewith. The mechanically - operated pistons have a common suction space which constitutes or is connected with a balance chamber. Liquid flows both during the opening and the stationary open period of the valves to the balance chamber. The pistons 2 for the inlet and exhaust valves are reciprocated by a shaft 16 oscillated from the engine shaft, and through the liquid pressure pipes 6 reciprocat the pistons 4 connected to the distributing- valves 5. The used liquid from the cylinders 3 passes by pipes 7 to the balancing-chamber 8, which is connected by a common pipe 9 to the chamber 13 around the cylinders of the pistons 2. The casing housing the pistons 2 and their driving-gear is made in two parts, one housing the pistons, and the other housing the shaft 16 and operating-levers 18, 21. The pistons 2 have ports and passages 41, 42 which register with the ports 39, 40 in the cylinder lining ; the tops of the cylinders are connected to the suction chamber 13 by non-return valves 15. The pistons are angularly adjusted by pinions connected thereto and operated by a toothed regulating-rod actuated by hand or a governor. The pinions may be independently regulated. The control pistons 4 have passages and grooves 27, 28, and their cylinders 3 have pressure and discharge recesses 25, 26. In the modified piston 4, Fig. 3, the centre part 29 is reduced, the bottom and the top of the cylinder act as dash-pots, and the bottom of the cylinder is connected to the pipe 6 through a non-return valve 34. A similar valve may be provided at the top of the cylinder. The piston is bevelled or slotted at 30, 31 to ensure gradual discharge of operative fluid and gradual closure of the valve respectively. The construction permits high valve speed. The valves may be closed by fluid-pressure in lieu of springs, and the gear may be adapted for uniflow engines. If the drive of the pistons 2 has an angle of advance of 90‹, reversal of the engine may be effected by interchanging the pressure and discharge conduits of the valves on the ends of the cylinders. In the construction shown in Figs. 4 and 6, a reversing slide valve or cock 43 is provided with grooves and passages 55, 56 to interchange the connections. A piston 58 is provided to put the liquid under pressure for starting independently of the engine shaft. Passages 60, 61, 64, 65 lead from the pressure space 59 to the cylinder liners. The pistons 2 have ports 68, 69 which register with the ports 66, 67 at starting. A cam 72 on a rod 22 actuates a lever 73 which controls a fluid supply, e.g. steam, to a piston 75 for operating the piston 58. When started, the cylinder 74 is put to exhaust, and a spring 77 returns the piston 58 to the right. In a modification the various parts are combined to form a single unit. A modification suitable for a fourstroke internal-combustion engine is described. The actuating-pistons are operated by eccentrics on a rotating shaft driven at half speed. Cranks or cams may be used instead of eccentrics. A construction is described wherein four cams on a shaft work the actuating-pistons through rollers and crossheads. The control rack is adjusted by a shaft governor through a lever with an eccentric fulcrum.