US531096A - Valve gear for steam engines - Google Patents

Description

(No Model) v 2 Sheets-Sheet 1.

L. 0. BURK. VALVE GEAR FOR STEAM ENGINES.

No. 531,096. Patented Dec. 18,1894.

INVENTOH Let Mm.

ATTORNEYS (No Model.) 2 Shees+Sheet 2.

L. 0. BURK. VALVE GEAR FOR STEAM ENGINES.

No. 531,096. Patented Dec. 18,1894.

HIEHHIIIIIIIIIH WITNESSES:

' yljm Elvrofi ATTORNEYS.

. .Urvrrs STATES ATENT Er c.

LEMON o. BURK, or .OORN'ING, ARKANSAS, ASSIGNOR TO HIMZSEILF AND DOUGLAS HOPSON, or SAME PLACE.

VALV E-GEAR- FOR STEAM-ENGINES.

SPEGIFIGl LTION forming part of Letters Patent No. 531,096, dated December 18, 1894.

Application filed June 1,1894. Serial N0. 513,153- (No model.)

To all whom it may concern:

Be it known that I, LEMON O. BURK, of Corning, in the county of Clay and State of Arkansas, have invented a new and Improved 5 Valve-Gear for Steam-Engines, of which the following is a full, clear, and exact description. The object of the invention is to provide a new and improved valve gear, which is simple and durable in construction, very effective in operatiomand arranged to permit of conveniently reversing theengine and delivering the steam directly into the ends of the cylinder.

The invention consists in certain parts and be hereinafter fully described and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming part of this specification, in which similar letters of reference indicate corresponding parts in all the views.

Figure 1 is a plan view of the improvement. Fig. 2 is a side elevation of the same. Fig. 3 is a sectional side elevation of the same, on the line 3-3 of Fig. 1. Fig. etisa transverse section of the same, on the line 44. of Fig. 3.

Fig.5 is a similar view of the same, on the ends of the cylinder A are arranged the straight ports a and 1), opening directly into the steam chest F, containing two valves G} and G, operating over the said ports a and b respectively, to control the inlet of the live steam to the said 03 linder and the outlet of exhaust steam therefrom. The two valves G and G are connected with each other by a valve stem G and the said valves are preferably made semi-circular in cross section, and are fitted to slide in correspondingly- 5o shaped casings H and H, fitted in the ends of the steam chest F, and open at their ends,

compartment of the steam chest.

details, and combinations of the same, as will H and H can be removed and are held in position by suitable lugs H projecting from the inside of the steam chest, as plainly indicated in Fig. 6. The valves G and G divide the steam chest into three compartments, of which the central compartment is connected with the inlet steam pipe F, leading to the boiler or other steam generator, so as to permitlive steam to enter and fill the middle The end compartments of the steam chest are connected with exhaust pipes F and F leading to the outside.

The outer end G of the valve stem G2 is pivotally connected by a connecting rod I with a block J, fitted to slide in the vertically disposed slot K of the link K, having trunnions K and K journaled in suitable bearings on the main frameof the engine. The

outer end of the trunnion K carries a crank arm K formed in its lower end with a slot K engaged by anadju'stable wrist pin L, connected with the eccentric rod N of an eccentric N held on the main driving'shaft E.

nions, so that the block J held ineither'the upper or lower end of the said link, is carried forward and backward 0n the rocking of the link. This motion of the block J is transmitted by the connecting rod I, to the valve stem G so that a reciprocating motion is given to the valves G and G in the steam chest F, to regulate the inlet of live steam to the ends of the cylinder, and'the outlet of exhaust steam from the cylinder in the usual manner. Now, in order to change the position of the block J in the slotted link K, to reverse the engine, I provide the following device: The connecting rod I, is connected near its front end with an eye 0 held on an arm 0 secured on a transversely-extending shaft P, journaled in suitable bearings arranged on the main frame of the engine. On the outer end of this shaft P is secured a downwardly-extending arm Q connected by a link Q with a reversing lever B, carrying the usual locking pawl R, adapted to lock the reversing lever on the segment S on which the reversing lever is pivoted. See Fig. 2. Now, when the several parts are in the position illustrated in Fig. 2, and the operator desires to reverse the engine, then he first unlocks the pawl R and then moves the reversing lever B to the right so as to shift the link Q to impart a swinging motion to the shaft P by the arm Q. The rocking of the shaft P causes an upward swinging of the armO, whereby the eye 0 imparts an upward swinging to the front end of the connecting rod I, whereby the block J is transferred from its lowermost position in the link K to the uppermost end, that is, on the opposite side of the trunnions K and K As soon as the block J slides past its central position in the link K, the valves G and G will be reversed, which reverses the engine in the usual manner.

By shifting the reversing lever B to an intermediate position the block J maybe moved nearer to the trunnions from either end, so as to cut off sooner or later as desired. Each of the valves G and G is provided with a suitable packing pressed by springs into contact with the segmental wall of the respective casing 11 or H, so as to prevent steam from leaking from the central compartment to the end compartments of the chest. The valve stem G is threaded and the valves G and G are.

held on the said rod by nuts screwing on the threaded portions of the valve stem, and on opposite sides or faces of the valves, as plainly indicated in Fig. 3.

The link K is made segmental, as plainly illustrated in Figs. 2 and 3, the center of the segment being in the center of the connection between the end G3 of the valve stem and the connecting rod 1.

By the arrangement described the ports a and b are veryshort and directly connect the cylinder with the steam chest so that the live steam can pass directly into the ends of the cylinder and thus insure full boiler pressure in the cylinder to act on the piston B. It will further be seen that the valves G and G balance each other, as the steam pressure is alike on both inner faces of the said valves.

Having thus described my invention, 1 claim as new and desire to secure byLetters Patent- 1. A device of the class described, comprising a reversing link adapted to be rocked from the main shaft, a block fitted to slide in the said reversing link, a connecting rod for connecting theblock with the valve stem, and a raising and lowering device for the said connecting rod, to move the block in the said reversing link, said device comprising a rock shaft having a rigidly connected arm provided with an eye through which the connecting rod slides, and means for adjusting the rock shaft substantially as shown and de scribed.

2. A valve gear for steam engines, comprising the slotted rocking link having a crank arm linked to the main shaft, a block adjustable in the slotted link, a cross head connected to the slide valve in the steam chest, a rod connecting said cross head with the block, a crank shaft above the cross head and having a rigidly connected arm projecting toward the slotted link and provided with an eye through which the connecting link reciprocates and an operating lever connected to the said rock shaft and provided with a locking mechanism, substantially as described.

3. The combination with a steam chest provided at its ends with openings and removable cover sections, valve casings in the ends of the casing and removable upwardly through said end openings, the middle portion of the chest forming the chamber for live steam and the portions beyond the said casings forming the exhaust chambers, ports a 1) leading directly from the two valve casings into the cylinder and two connected slide valves working in said casings, substantially as described.

4. The combination with the steam chest having openingsin its top at both ends, cover sections therefor, lugs 11 in the side walls of the chest in line with the openings, valve casings inserted removably into the chest through said openings and held in place by said lugs, ports a 1) leading from the live steam chamber into the cylinder and exhaust chambers in the ends of the chest, of the two connected valves mounted in the respective valve casings and provided with spring seated packings, substantially as described.

LEMON O. BURK.

Witnesses:

H. J. WEINAD, L. S. FERGUSON.

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