US336862A - Cut-off valve for steam engines - Google Patents

Description

(No Model.) 2 Sheets-Sheet 1.

M. N. LYNN. GUT-OEE VALVE EOE STEAM ENGINES.

No. 336,862. Patented Feb. 23, 1886.

N4 PETERS1 Photlithogmpher, Wnshngkm. D. C.

(No Model.) 2 sheets-sheet 2. M. N. LYNN.

.GUT-OEE VALVE EOE STEAM ENGINES. No. 336,862. Patented Feb. 23, 1886.

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UNITED STATES PATENT OEEICE.

MIRABEAU N. LYNN, OF RISING SUN, ASSIGNOR TO THE AMERICAN ELEC- TRIO HEADLIGHT COMPANY, OF INDIANAPOLIS, INDIANA.

CUT-OFF VALVE FOR STEAM-ENGINES.

SPECIFICATION forming .part of Letters Patent No. 336,862, dated February 23, 1886.

Application filed June 1, 1885. Serial No. 167,291. (No model.)

To ail whom, it may concern.-

Be it known that I, MIRABEAU N. LYNN, of Rising Sun, in the county of Ohio and State of Indiana, have invented certain new and useful Improvements in Out-Off Valves for Steam- Engines; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the figures and letters of reference marked thereon. l

This application is filed as a division of my application No. 158,898, led March 14, 1885;

and the invention relates to certain improvements in the construction, arrangement, and combination of the valve-actuating mechanism especially designed for use in connection with the devices as described in said prior application, but applicable to other constructions of engines, as'will be apparent.

` The manner of constructing and applying my said invention will first be described, and the particular features sought to be covered herein will be pointed out in the claims.

In the accompanying drawings, which are designed to illustrate one mode of applying my said invention to practice, Figure l is a sectional view of my improved valve-operating mechanism arranged for application to a multiple-cylinder engine. Fig. 2 is a similarview of a modified form of valve. Fig. 3 is a side elevation, partly in section, o n the line :c x, Fig. l. Fig. 4 is a detail showing the manner of connecting the cut-off Valve to its pitman.

Similar letters of reference in the several iigures indicate the same parts.

The letter A designates a portion of the main casing, A one of the piston-cylinders, A2 the valve-cylinder, and B the main driving-shaft, said parts being the same as shown in my application No. 158,898.

Three pairs of cylinders, A A, are employed, all of the same construction, projecting radially, and located at equal distances apart upon the main casing A, Within which latter the working parts of the engine are inclosed.

The steam-valve proper, or that by which the cylinders are alternately put into communication with the steam chest or pipe leading from the boiler and the exhaust, consists of a tubular valve,` D, provided with the inletports d and exhaust-ports d', and arranged to reciprocate in the valve-cylinders A2. The valve D is divided into two sections by a diaphragm or piston, E, the outer section opening into the steam-chest d2, and the inner communicating with the central chamber, A. Within the valve-cylinder A2 is formed an annular chamber, da, with a passage, d4, leading to the cylinder A. When the valve D is reciprocated in the cylinder A, the steam is admitted to the cylinder Athrough the ports d, and exhausted through the ports d as those ports are brought opposite the chamber d3, as is well understood.

It is my intention that the valves D shall have the Widest and best proportioned ports, to freely admit and exhaust steam in the cylinder, and shall also be given a definite and regular movement, and to this end they are arranged to be driven by a fixed eccentric or eccentrics on the main shaft B.

In the present instance two eccentrics, D D", are employed, set at the same angle and having the same throw; hence they operate substantially as one eccentric. Two pitmen, d, are employed for each valve D, one extending to the eccentric D' and the other to the eccentric D2. The manner of attaching and applying these pitmen is as follows: In the lower or inner end of the valve D are drilled or otherwise formed diametrically-opposite openings or bearings dl, to receive a boss or pin, el, projecting laterally from the outer end of the pitman d, The boss or pin l5 being inserted in the bearing dm, is retained in place by means of a pin or soft wire, di, inserted through a transverse opening formed in the valve, said Wire resting Within a circumferential groove in the boss or pin d5, and having its ends bent down, as shown. By this method of attaching and securing the ends ofthe pitmen to the valve I am able to dispense with the usual nuts, screws, &c., which are liable to becomeloose, and at the same time simplifying the construction and facilitating the attachment and removal of the parts.

The lower or inner end of each pitman is provided with an arc-shaped saddle, da, rest- IOO ing upon the face of the eccentric, the several saddles being held in place by a divided ring, d, resting in a groove, as shown in Fig. 3, and, if desired, a ring or flange, 19, may be formed upon the face of the eccentric, and the inner faces of the saddles may be grooved to t said ange,whereby the pitmen will be more accurately held and prevented from twisting or becoming misplaced.

While this method of attachment and guiding the pitmen is believed to be novel and to possess marked advantages, it is obvious that other devices capable of properly and securely retaining the pitmen may be substitutedsuch, for example, as those shown in my prior application applied to the piston and crank.

Having thus described the piston and valveoperating lmechanism, which, as combined, constitute an eicientsteam-engine, I will next proceed to explain how a cut-off can be applied,which,without diminishing the pressure of the steam in the steam-chest, or as delivered to the cylinder through the valve D, shall l quickly and positively interrupt the flow of steam through the valve at any desired point in the stroke ofthe piston. The devices shown for accomplishing this object consist, essentially, of the piston E, (when the automatic cutoff is not employed this is fixed and serves only as a diaphragm separating the steam- .valve into its two sections, as described,) located within the tubular valve D, and Vlying normally between the inlet and exhaust ports, a pitman, E', and an adjustable eccentric or driver, E2, for giving` the requisite movements to the piston E, as will be described.

The pitman E can be conveniently attached to thepiston E in the following manner: To the center of the piston is applied-as by va screw threaded connection-a detachable plug, e, in the end whereof is formed'a transverse open bearing, e. lThe end ofthe pitman E is formed with atransverse semi-cylindrical boss or head, e2, adapted to slide endwise within the bearing e', and when in place the two are ,fastened in position by a pin or soft-metal .wire, es, engaging a groove in the head e2,and having its ends bent to prevent accidental withdrawal.

It will be observed that the pitman E is somewhat longer than the pitmen d6, and as it passes up between said pitmen and into the valve D it serves as an additional means to prevent the accidental withdrawal of the heads of the said pitmen from the sockets or bearings ink the valve D. As, however, the pitman E when thus arranged obstructs, inV

a measure, the exhaust-passage, it is found expedient to provide additional passages 212 through thelower portion of the valve D, (see 1 Fig. 1,) through which the exhauststeam can escape, said passages supplementing the exhaust through the center of the valve.

The eccentric E2, for actuating the piston E, is preferably located between the eccentrics D D2, being supported upon the sleeve d.

This sleeve. d, secured to the eccentric D, is concentric with the shaft B, and to it is also removably applied the eccentricl D2, whereby the several eccentrics are detachably secured together and to the shaft B.

Themanner of attaching or applying the several pitmen E to the eccentric differs somewhat from that employed with the other pitmen, for the reason that as each piston E is subjected to the direct action of the steam in the steam-chest the pressure and friction upon the eccentric would be unduly multiplied. In order to overcome this objectionable feature, vI form one of the pitmen E with adivided collar, e5, embracing the eccentric E2, and to this collar I pivot the inner ends of the remaining pitmen, connecting them by a joint similar to that employed for attaching their outer ends to the pistons E,as shown in Fig. 3. As thus arranged,the pressure of the steam upon the several pistons is borne by the collar e5, instead of the eccentric, and a practical balancing of the pistons and their connecting mechanism is thereby secured, so that but little power is required to turn the eccentric and actuate the pistons.

The mechanism described constituting the cut-off is designed to operate in the following manner: The three eccentrics D', D, and'lll2 are arranged to move with and be revolved by the shaft B. The eccentric E2, which has the saine throw as the eccentrics D D2, being set at the same `angle as the valve-eccen tries, the piston E will be moved in unison with the valve D and operate merely as a fixed diaphragm, the admission and exhaust of steam being effected by the valve D alone. When now it is desired to cut off the steam at any point in the throw of the piston, so it may act by expansion only, the eccentric E2 is setl forward or in advance of the eccentrics IOC D D2 the proper distance, the effect of which inlet-ports on the inner side and cuttingr offv the supply of steam at a point where the valve D would otherwise continue to admit it to the cylinder.

In Fig. 3 the eccentric E2 is set at a point on the shaft diametrically opposite the eccen trics D D2, and in position to cut off at about one-eighth stroke.

It will be noticed that4 the stroke of the IIO valve proper, D, remains the same under all circumstances, opening wide the inlet and exhaust ports, while the piston F, constituting the cut-off, operates quickly. The'piston and valve moving in opposite directions and at any desired part of the stroke, according to the position in which the eccentric Ez is placed,

is adapted to cut off the steam-supply, while the exhaust is not interfered with, but remains full and open.

Any appropriate regulating mechanismv may be applied for automatically setting and adjusting the movable eccentric; but I prefer to employ that illustrated and claimed in my before-mentioned application.

Owing to the manner of constructing and combining the direct-acting steam-valves and the cut-oft` valve and their actuating mechanism, I am enabled from the same patterns, and7 in fact, from the same organized machine, to construct an engine that is adapted for operation either with or without a cut-off.

As before stated, the piston E, which performs the office of a cut-oli valve, serves as a diaphragm to separate the tubular steamvalve D into two sections, the one containing the inlet and the other the outlet or exhaust ports. Vhen it is desired to dispense with the cut-off and its actuating mechanism, the

said piston E is fixed in position within thel valve D, to do which it is only necessary to secure the said piston to the walls of the valve D by any suitable fastening; or if the governing mechanism alone is dispensed with the eccentric E2 may be fastened to the eccentrics Dl D?, or to the sleeve da. Thus it will be seen the same structure is adaptedjfor use either with or without the cut-off feature, and the cut-ofi` actuating devices can be applied or omitted altogether without requiring any alteration in the structure of the engine or change or modification of its operating parts.

I claim as newl. In combination with the valve-cylinder, the tubular steam-valve having inlet and exhaust ports, as described, the independentlymoving cutoi` piston located within the tubular steam-valve, intermediate the inlet and exhaust ports, substantially as described.

2. In combination with the tubular steam- Valve, its connecting-rod,and actuating-eccentric made fast to the main shaft, the cut-ofic piston or valve operating within said steamvalve, the pitman and its movable driving eccentric, substantially as described.

3. As a means for connecting the steam- Valve and cut-off to the driving-eccentrics, and in combination therewith, the two pitmen piv-l otallyr connected to the steam-valve, and the pitman pivoted to the cut-off piston,extending between and beyond the point of attachment of the yfirst-mentioned pitm'en, substantially as and for the purpose set forth.

4. Inasteam-engine, as ameans for pivotally securing the pitman to the valve, and in combination with the latter, the detachable plugs provided with the transverse open socket, and the pitman having the transverse pivot adapted to enter said socket, substantially as described. f

5. In combination with the` pitman, its transverse pivot, and the socket-bearing in the valve, as a means for preventing their accidental separation, the soft-metal pin passing through the bearing and engaging a circumferential groove in the pivot, substantially as described.

6. In combination with the tubular valve having diametrically-opposite sockets in its lower end, the two pitmen, each provided with pivot-pin entering one of said sockets, the cut-off piston situated within said valve and above its sockets, and the pitman fastened to said piston and extending between the pivot-pins of the first-mentioned pitmen,

whereby the latter are prevented from becoming accidentally displaced, substantially as described.

7. In combination with the valve-cylinder having the steamchest and collars forming the annular chamber communicating with the engine-cylinder, the perforated tube passing through said collars, and the tubular valve composed, essentially, of the two open-mouth cup-shaped extensions, and the intermediate piston or diaphragm, substantially as and for the purpose set forth.

8. In a steam-engine such as described, the combination, with the tubular steam-valve and its actuating devices, of the piston located within said valve intermediate the inlet and exhaust ports, whereby said piston is adapted to serve as a diaphragm dividing the steamvalve into the two sections, as described, or by the application of actuating and governing mechanism may serve as a cut-off valve, substantially as described.

MIRABEAU N. LYNN.

Vitnesses:

D. S. WILBER, E. P. LYNN.

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