Patent GB-446569-A (GB)
Title: Improvements relating to steam engine distributing valves and operating mechanism therefor
IPC: F01L31/16
Filed: 1934-08-01
Abstract: 446,569. Engine distributing-valves and valve-gear. JOUANNO, C. G., P.O. Box 21, Nairobi, Kenya, Africa. Aug. 1, 1934, No. 22471. [Class 122 (ii)] Comprises an arrangement of separate inlet and exhaust, sleeve, slide valves which are actuated by cam releasing-gear. The admission and cut-off varying means comprises a main cam for opening the steam valves through releasable intermediate mechanism, and a secondary cam which is adjusted angularly in relation to the main cam and effects the release. A multiple-cylinder arrangement for locomotive engines with forward and reverse cams for the inlet and exhaust valves, is described. The releasable mechanism comprises independent slidable and rockable members, or members which may both slide and rock ; the rockable members are moved out of the path of the main cam thrust by the secondary cam. The main cam shaft 3 is driven by cranks 4 operated by the engine shaft through bevel or other gearing. Forward and reverse cams 5a .. d, 6a .. d are provided. The cams 5a, 6a, 5b, 6b operate the inlet valves; the cams 5c, 6c, 5d, 6d operate the exhaust valves. The intermediate mechanism 10e .. 10h comprises sliding- rods 15, 16. Each rod 15 carries a roller engaging a main cam, and is slotted to slide about a downwardly projecting limb 18a of a fixed guide 18b between which and a casing surface 19 the roller rims. The rods 16 slide in guides and actuate the exhaust valves of the two cylinders through cranks directly and through transmission mechanism respectively. The inlet valve mechanism is similar to the exhaust mechanism but embodies the disconnectable connections actuated by the secondary cams 23. The push rod 24, Fig. 2, pivots about its roller 17 and carries a roller 28 which engages a concave portion 29 of a head 30 on the inner end of the valve actuating-rod 25. At cut-off, the roller 28 is raised to clear the head 30 by a bell crank 31, one end of which is connected thereto by a link 32, and the other limb with a roller 33 which rotates on the secondary cam 23, Fig. 1. The released inlet valve closes under a steam load. The bell-cranks 31 include upwardly projecting arms 35 connected by telescopic tubes containing springs which retard the return of the rods 25 and the closing of the valves. The secondary cams 23 are secured to a drum 38 borne by the main cam shaft 3 which is hollow to receive a screw shaft 39 connected to the drum 38, and which is adjusted angularly by a threaded sleeve connected to a pin 41. Axial movement of the sleeve 40 is effected by means of the pin 41 which engages the main race of a bearing 13, Fig. 6, which is moved longitudinally by pinion- and-rack mechanism 48, 47, 44. Axial movement of the main cam to effect reversal is transmitted from the rack 44 by means of a cam track 57 which engages a roller 58 on a lever secured to a shaft 52 which through a spring-pressed bell-crank moves a thrust bearing 14 secured to the cam shaft. The valve comprises a cylindrical body 60 open at both ends and provided with a wall having a plurality of ports which register with ports 64 in a cylinder 61 in the chest 62. The wall 71 of the valve is of spring form and is housed in recesses 72 in the body 60. Renewable packing-rings may be inserted between the body 60 and the wall 71. Alternatively, the ports may be formed at the bottom of packing-ring grooves, apertures being formed in the rings. The valve spindle 66 is enlarged to constitute a plunger 66a upon which steam acts to close the valve. A pipe 70 leads to the exhaust-valve spindle.