Patent GB-389809-A (GB)
Title: Self controlling cams
IPC: F01L31/16
Filed: 1931-06-20
Abstract: 389,809. Engine valve-gear. BUONOCORE, A., 36, Via XX Settembre, Genoa, Italy. June 20, 1931, No. 17896. Convention date, June 20, 1930. Void [Published under Sect. 91 of the Acts]. [Class 122 (ii).] Cam gears ; combined fluid-actuated and mechanical gears.-The valves of marine, stationary, &c. engines are operated by adjustable cam mechanism operating in conjunction with relieving-cylinder mechanism which functions to take the load off the cams during action. The gear is adapted for starting and reversing the engine, and the cams may oscillate or rotate. The cam mechanism comprises contoured. disc members relatively angularly adjustable, certain members being fixed to the operating-shafts, and others rotatable thereon. A reversible gear may comprise a fast member with two loose members, or two fast members each associated with a loose member, each group operating the valve in one direction, or a fast and a loose member for one direction mounted on a side shaft, and a reverse group mounted on the engine shaft. When only forward adjustable cut-off is desired, the reverse is effected by a single, fast member in one with the forward member. A single fast member is divided into two operating zones upon which the valve-actuating rollers-run. Each zone is normally divided into six steps, which, with constant reverse cut-off, are provided on the cam member fixed to the shaft. With forward variable cut-off, two steps are provided on the loose cam disc, and two on the fixed disc. Forward and reverse cams are shown in Figs. 2 and 3. The cam sectors and steps correspond to the phases of the steam distribution relative to a direction of rotation. A two-piece cam member shown in sectional plan, Fig. 8, has an adjustable cam disc, Fig. 7, mounted in the V-slot, Fig. 8, and comprises a cam giving variable forward cut-off and constant reverse cut-off. Pairs of steps on the adjustable element control the admission and cut-off at the upper and lower ends of a cylinder. On rotating one of the disc d when the engine is stopped, the bevel teeth c on its face operate through bevel pinions c<1>, c<2>, c<3>, Fig. 9, and worm and screw-and-nut gearing, the blocks m to move a block in a slot f and so displace the cam Pm, Fig. 7. When running, a shoe-brake may actuate the discs d to effect adjustment. In a modification with constant reverse cut-off, a pair of adjusting-discs is mounted between pairs of fixed and movable discs and the discs have spiral surfaces which engage worm pinions which through screws effect the adjustment of the blocks m to adjust the movable cam piece. The rollers operating the valves and engaging the actuating-cams, are held in position by pistons in auxiliary relieving-cylinders which are controlled by auxiliary cam-operated valves, and the pistons in which alternately force the rollers towards and awav from the main cams to relieve the strain. The main cams accordingly are supplied with counter-guides g, Fig. 16. The relieving-cylinders take the strain on the gear while the rollers pass from one zone to the adjacent zone on the actuating-cams. Methods of co-ordinating the action of the cam mechanism and relieving-cylinders through regulating link-motion &c. means are described.