US45663A - Improvement in valve-gear of steam-engines - Google Patents

Description

UNITED STATES PATENT 0EEIcE.

A. II. -VOODRUFF, OF LANSING, IOIVA.

IMPROVEMENT IN VALVE-GEAR OF STEAM-ENGINES.

Spccilleation forming part of Letters Patent No. 45,663. dated December 27, 1864.

To all whom it may concern.-

Beit known that I, A. H. WOODRUFF, ot' Lansing, in the county ot'Alleinakee-and State of Iowa, have invented a new and uset'ul Improvement in the Valves and Valve-Gear of Steam-Engines; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part ot' this specification, in which- Figure 1 is a side view of a steam-engine having my invention applied, the cover ofthe steain-chest being omitted to show the valves. Fig. 2 is a transverse vertical section in the plane indicated by the line 0r a', Fig. l. Fig. 3 exhibits a section ot' one of the valves in a plane parallel with Fig. 1, and shows the arrangement of the ports in the seat. Fig. 4 is a vertical section of the valve in the plane indicated by the line y y in Fig. 3.

Similar letters ot reference indicate corresponding parts in the several figures.

This invention consists in a novel construction and arrangement ofthe valves and ports by and through Which the induction and eduction of steam to and from the cylinder ot' an engine are et't'ected, and a novel mode of operating the valves, whereby I am enabled to work the valves for running the engine in either direction with one eccentric, and to ei'- i'ect the stopping, starting, and reversing of the engine Ioy means of one lever.

To enable those skilled in the art to make and use my invention, I will proceed to de scribe its construction and operation.

A is the cylinder ofthe engine; B, the valvechest; G, the crank-shaft; D, the crank; E, the valve-eccentric, and F the eccentricrod, all constructed and arranged substantially as in horizontal steamengines now in common use.

G G' are the valves, one for eii'ecting the induction and eduction of steam to and from one end of the cylinder, and the other for effectin g the induction and eduction to and from the other end. These valves are ofthe sliding kind and work vertically or at right angles with the piston. They are attached to opposite arms a a of a rock-shaft, H, which works in a bearing in a column, I, which is movable lengthwise or in a direction parallel with the movements of the valves and at right angles to the movement of the piston, as will be hereinafter more fully described, for the purpose ot starting, stopping, and reversing the engine. The lower part of this column works in a stationary cylindrical guide, J, and the upper part in a guide in a stationary arch, K. The said column is connected with a hand-lever, L, Fig. 2, which works on a fixed fulcrum, b, and this lever works in a stationary notched segment, M, to which it can be locked by a sliding bolt7 c, attached to the lever and entering one ofthe notches d d ot' the segment. The valve rock-shaft H has a third arm, e, with which the eccentricrod is connected to giveit the proper movement to work the valves. The column I does not move in the ordinary operation of the valves, when the engine is running steadily in one direction.

ff are the two ports through which the induction of steam from the valve-chest into the cylinder and the eduction from the cylinder into the exhaust-cavities of the valves are effected. g g are the tivo ports through which the eduction ofthe steam from the cavities ot' the valves to the eduction or exhaust pipe is effected. Each otl the ports f f and its respective port, g or g', are arranged side by side at right angles to the movement of the valves, as shown in Figs. 1 and 3. The valves G G are made with cavities hh in their faces, substantiall y like the common short D-slide valve; but the said valves are wide enough to work over the two portsfg orf g', and the portion which works over the port g or g is longer than that which works over the port f or j". When made without lap, the whole length of the portion of the face which works over the portf or j" is equal to four times the width of the port, and the length of the corresponding portion of the opening in the face equal to twice the width of the port, and the length of the opening in that portion ot the face which works over the ports g or g is five times the width of the port. The length of stroke of the valve is the same as that of an ordinary short slidevalveviz., equal to twice the length of the port for f or enough to open lthe port full to the steam and to the cavity of the valve by turns.

In the operation of the valves produced by the operation of the eccentric on the rock-shaft H the portf or f' is uncovered to admit steam at the same time that the other port, f or f, is brought into communication with the interior ot the valve. When the column I is raised by bringing the lever L down to the lowest notch, (l, ot' the segment M, the rock-shaft and valves are raised to such a position that the induction is eii'ected under the lower edge ofthe valves; but when the saidcolumn is lowered by bringing the lever L up to the highest notch, d', the roch-shaft and valves are lowered to such a position that the induction is ei'ected under the upper ed ges of the valves. The movement of the column necessary to effect this change is equal to twice the width of the ports, and by giving the column this movement by means of the lever L, or by any other suitable means, the direction ofthe engine is reversed. The drawings show the column in its highest position and the induction to be eit'ected under the lower edges of the valves and the revolution of the shaft ot' the engine in the direction ofthe arrow shown in it in Fig. l.

By bringing the lever to the central notch, d2, and so bringing the column I and rockshaft H to a central position, the valves are brought to such a position that by the operation ofthe eccentric and rock-shaft the ports ff will not be uncovered and the engine will be stopped. The engine may then be started in either direction by raising or lowering the lever, according to the direction desired. By

bringing the connection ot' the eccentric-rod F with the arm e nearer to the rock-sliaft,and so giving' the valves an increased movement,

the shifting ofthe lever L to a notch, cl3 or di, ofthe segment above the lower notch, d, or below the upper notch, d', will be made to reduce the opening of the ports, and thereby slow the engine.

In very large engines the column, rock-shaft, and valves may be raised by admitting steam into the cylinder J below it, and lowered by opening an exhaust-cock to let out the steam from the said cylinder and permit the descent of lthe column, rock-shaft, and valves by their own weight. y v

I am aware thata movable column and rockshaft have beforebeen applied to a cut-oft'- valve gear. My claim is therefore limited to the combination of devices by which I am enabled to eii'e'ct the stopping, starting, and reversing of the en gine all by means ofa single lever.

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

The attachment of the valve-operatin g rockshai't and valves to a movable column, I, by which they may be raised or lowered or otherwise moved in such a manner as to effect the induction at one or other edge of the valves, substantially as and for the purposes herein specitied.

Ae n. WOODRUFF.

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