US37342A - Improvement in valve-gear of steam-engines - Google Patents

Description

UNITED STATES `PATENT OFFICE.

IMPROVEMENT IN VALVE- GEAR OF STEAM-ENGINES.

p Specification forming part of Letters Patent No. 37,342, dated January 6, 1863.

.To a/ZZ whom it may concern:

Be it known that l, W. R. GEEENLEAF, of Silver Creek, in the county of Chautauqua and State of N ew York, have invented certain new and useful Improvements in the Valve- Gear of Steam-Engines 5 and I do hereby declare that the following is a full, clear, and exact description of the same, reference bei ing had to the accompanying drawings, forming partof this specification, in which- Figure l is a side view of a double marine- Y propeller engine having myinvention applied, the shaft being represented in section. Fig. 2 is a vertical section of the principal portions of the valve-gearlengthwise of the shaft. Fig. 3 is a longitudinal outside view of a portion `of the same. Fig. 4 is a diagram illustrating the operation of the eccentrics.

, Similar letters of reference indicate corresponding parts in the several figures.

This invention consists in a certain arrangement of valve-connections whereby a single eccentric is rendered capable of operating the two induction andeduction valves ofa double engine with suitablyarranged cylinders.

It also consists in certain novel and simple means of shifting the eccentric for the purposes of varying the length of travel and reversing the movement of the valve, whereby a single eccentric is made to effect in a better manner all that is effected by two eccentrics and a link-motion.

To ena-ble others skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A is the framing of the engine, and B B are the cylinders set at opposite inclinations in a plane or planes perpendicular to the crank-shaft C, and having the piston-rods 4working through their lower ends to be connected with the crank-shaft, whichis arranged below the cylinders. The cylinders are supposed to be fitted with oscillating valves, the stems a a of which are represen ted in Fig. l as furnished with crank-arms b b', connected by two rods, c c', with the ring E of the single eccentric D. One of these rods, o, is rigidly attached to the eccentric-ring, but the other is attached by a pivot-joint, d, as some little play is necessary between the two rods. The arrangement of the valves and their crankarms b b is such that the two eccentric-rods c c will, when either valve is at half-stroke,

be at the same angle` to each other as the cylinders B B', and by that means the single eccentric is made capable of working the valves of the two cylinders. llt is to obtain on the shaft, or be movable for the purpose of reversing the engine or varying the stroke of the valve. The eccentric D is movable, and its movement is provided for in the following manner:

F is a disk fast upon and concentric with the crank-shaft and having in its face a slot or slots, f, running parallel with the line in which the eccentric D is t be moved to reverse or vary its throw. The eccentric is made with a tongue or tongues to fit and slide in this groove and is provided with an elongated opening, g g, the parallel sides of which are at right angles to the length of the tongues e and grooves f, such opening receiving a smaller eccentric, G, which is fast upon a sleeve, H, which is fitted to turn easilyT on the crank-shaft C. This eccentric G, which may be termed the inner eccentric,to distinguish it from the main eccentric, D, ts snugly be1 tween the sides of the opening g g, so that it will be caused by any movementof the sleeve H around the shaft to shift the main eccentric in a direction parallel with the tongues and grooves e f. Whenthe inner eccentric, G, is turned to a position in which its eccentricity to the crank-shaft is in a direction parallel with the sides of the opening gg and at right angles to the tongues and grooves e f, the main eccentric will be brought to a position only just sufficiently eccentric with the shaft, as illustrated in black outline in Fig. 4, to operate the valve the distance of its lap and lead, and thus will cause the stoppage of the engine, but by turning the said eccentric G either in one direction or the other from this position it will give the main eccentric a greater throw in the corresponding direction,

as illustrated by red and blue outlines in the same gure, and make it give steam to the engine for working in one direction or the other, and hence the single main eccentric is made capable of effecting all that is effected by two eccentrics with a link-motion, and by using this mode of shifting the eccentric, in combination with the system of eccentric-rods and valve-connections hereinbefore described, a single eccentric is made capable of effecting all the necessary movements of the valves of a double marine-en gine.

To provide for the turning of the sleeve H while the engine is in motion there is fitted to the exterior of said sleeve a second sleeve, I, a portion of which is also tted to feather, h, on the crank-shaft, so that the said sleeve I is compelled to turn with the said shaft, though permitted to slide longitudinally thereon, as well as upon the sleeve II, which is prevented from having a longitudinal motion. The sleeve H 'has cut in its eX- terior a spiral groove, c', and the outer sleeve, I, has secured in it a pin, j, which enters the said groove, and which should be fitted with a slide, K, or roller, fitting easily into the groove i. .The outer sleeve, I, has also provided in it a circumferential groove, le, for the reception of the forked end of ,a lever, which works on aXed fulcrum, and by which the longitudinal movement of the said sleeve may Abe effected. In this longitudinal movement the pin j, by'its movement along the groove c', produces the movement of the sleeve H around the shaft.

In applying the movable eccentric, operated as above described, to locomotive-engines, the arrangement of the cylinders renders it necessary to have a separate main eccentric, D, for operating each valve, and each main eccentric requires a separate inner eccentric, G, one on each end ot sleeve H.

Some of the advantages which this system of valve-gear has over the two eccentrics and link-motion may be enumerated as follows: First, it is more simple and of less expensive construction; second, it has fewer parts, weighs less, and takes up less room, all very important considerations in a locomotive; third, it gives a better and more perfect movement, obviating the inequality of movement and variation of lead which are unavoidable with the link-motion fourth, it is less liable to get out of repair and more easily kept workin g steam-square;77 fth, it is more easily reversed, and more easily held in any desired position.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. The combination and arrangement of the valves, valve-stems, or valve rock-shafts,

and ofthe two eccentric-rods c c', attached to the same eccentric, substantially as herein described, whereby the one eccentric is made to operate the valves of both cylinders of a double engine, as herein set forth.

2. The employment, for operating the inner eccentric, D, of two sleeves, H I, the one moving around and the other sliding longitudinally upon the crankshaft, the two combined by a spiral groove, i, and pinj, and the whole operating substantially as herein specified.

W. R. GREENLEAF. Witnesses:

HENRY WHEELER, Trios. G. MoRsE.

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