US374752A - pelton - Google Patents

Description

- 2 Sheets-Sheet 1. G. M. PELTON.

VALVE GEAR.

(No Model.)

No. 374,752. Patented 960.13, 1887.

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(No Model.)

G.-M. PELTON.

VALVE GEAR.

7 8 I 8 V g m m k V. T W 6 D d e t n e t a P .NITED STATES ATENT Fries.

GEORGE M. PELTON, OF BELMONT, NEW YORK, ASSIGNOR TO \VILLIAM P. CLARK AND CHARLES E. CLARK, OF SAME PLACE.

vALvE-eEA R.

SPECIFICATION forming part of Letters Patent No. 374,752 dated December 13, 1887.

Application filed December 1, 1886. Serial No. 220,358. (No model.)

To all whom it may concern: v

Be it known that I, GEORGE M. PELTON, a

citizen of the United States, residing at Belmont, in the county of Allegany and State of New York, have invented certain new and useful Improvements in Valve Gear, of which the following is a specification, reference being had therein to the accompanying drawings, in which- Figure 1 represents a plan,-with parts in section; Fig. 2-, a vertical longitudinal section through the line X X. Fig. 3 is an elevation (on a larger scale) of the governor, showing its connection with the eccentric. Fig. 4shows a section of the eccentrics also on a larger scale. Fig. 5 is an elevation of a modification. Fig. 6 is asection of the modification shown in Fig. 5, but with the parts in a different position.

This improvement relates to that class of cut-offs in which two valves are usedone to admit and exhaust steam to and from the engine and the other to cut off the steam from the main valve; and the invention consists in the peculiar construction and arrangement and combination of parts, hereinafter more particularly described,and then definitely pointed out in the claims.

Referring now to the details of the draw- 0 iugs, A represents the frame of the engine; B,

the cylinder; C, the piston-rod; D, the pitman, connected by the wrist-pin E with-the crank-disk F and shaft G, to give the latter motion in the usual manner. As nothing is 5 claimed on these parts, a fuller or further description is unnecessary.

Mounted fast on the shaft G is an eccentric, H, which, to distinguish from another one, I call the fixed eccentric, and which drives 0 the main valve I by means of the link J, which is pivoted to the valve-rod K. On the main eccentric is journaled a cut-off eccentric, L, connected with the cut-off valve M, that slides on the main valve, by the link N and valve- 5 rod 0. This cut-off eccentric I intend to adjust on the main eccentric by any suitable connection with a governor, and asa specimen of the style of governor I prefer to use I show one in which weighted levers and springs are used, as indicated more particularly in Fig. 3, in which 1? is a wheel or casecarrying .the eccentric, and it may be placed on the pivoted weighted levers Q Q, which are connected by the links R R with the cut-off eccentric L, and are provided with springsS S, the ends ofwhich are connected to the levers and to the wheel or case in any convenient manner.

The weights T on the levers are provided with setscrews, by which they can be set at the desired place on the levers. The valve I has inlet-ports it and an exhaust-portJ; but the cutoff valve is without ports, as it eonsists simply of two metal blocks, m m, connected by a bar, at.

In the operation of this cut-off steam is admitted to the cylinder-ports b 5 through the ports 2' 'i in the valve I, and is exhausted through the port z". The closing of the" ports I) b and the opening of the exhaust always occurs at fixed points in each stroke, being governed by the main or fixed eccentric; but the closure of the inlet-ports t i in the valve I is varied by the cut-off eccentric L, the position of which is controlled by the governor-weights T T. In maintaining the equilibrium between the flying weights T and the springsSSasthe engine varies in speed, the weights will move out and in, thus varying the position, of the eccentric, and consequently the cut-off valve, accordingly, and closing the ports i i at an earlier or later period in the stroke, giving a greater or less amount'of steam, according to the variation of the load on the engine.

Although the time of cutoff of the cut-off valve'varies, as shown, the travel of the cut off valve on its seat on the back of the main valve is always the same, owing to the fact that the centers of the cut-offand main eccentries are fixed relatively to each other. This is very important, for if the travel of one valve on the other varied, as it would if the two eccentrics were not concentric with each other, it would Wear the surface of the lower valve unevenly, causing leakage. By journaling the cut-off eccentric on the main eccentric it enables me to'connect the cut-off 5 eccentric directly to its valve without intervening mechanism. v

Figs. 5 and 6 show a modified form of my invention that accomplishes the same effect as outer end of the main shaft B or on aseparate shaft driven from the main shaft, if desired.

and is connected to the flying weight T by I means of the arm XV and connecting-link It. It is evident that either of these devices-viz., the eccentrics or the cranks-may be used to give the motion to the main and cut-ofi'valves,

and I should consider the cranks as an equivalent for the eccentrics, and mean to be understood as claiming the eccentrics, the cranks shown, or any equivalent for them when using the word eccentrics in the following claims.

It is evident that the cut-off eccentric might be mounted on an eccentric collar independent of the main eccentric, but having its surface concentric with the acting-surface of the main eccentric, which arrangement I should consider as the full equivalent of that heretofore described and shown, as it is obvious that it makes no difference whether the eccentric collar onwhich the cut-offeccentric is mounted is in one piece with the main eccentric or is separate therefrom.

I am aware that a movable eccentric controlled by a governor for working a cutoff valve had been mounted on a fixed eccentriceccentricall y to the acting-surface of said fixed eccentric, as shown in the English Patent No.

2,213 of 1859, and make no claim to the same,

as I consider my invention essentially different from the arrangement shown in the patent referred to, for in that case, when the adjustable eccentric is changed, the cut-off valve travels over a place on the main valve different from that it did before the change of the eccentric was made. This is objectionable for the following reason: When the cutoff valve has been traveling for some time over one part of the surface of the main valve, a certain amount of wear takes place, so that the surface of the main valve traveled over by the cut-off valve is slightly lower than the other part of the valve. If the eccentric is now changed, the cutoff valve travels over a portion of the valve that has been previously worn and over another portion of the valve which has not been worn, and a leak is therefore caused by the difference between the worn and uuworn surfaces. This is avoided by my arrangement, for the cut-off valve always travels over precisely the same surface on the.

main valve, no matter how much the eccentric is shifted- Consequently the wear is always even, and thus leakage is prevented.

Having thus described what I consider the preferable form of my improvement, but without limiting myself to the construction shown, I claim as new- 1. The combination, in an engine, of main and cut-off valves and an eccentric connected to a governor for controlling the cut-0E valve and journaled concentrically to the actingsurface of the main eccentric, whereby the rubbing-surfaces between the two valves remain always the same, substantially as described.

2. The combination, with the shaft of an engine, of two eccentrics, one of which operates the mainvalve and is fast on the shaft,

and the other is connected with the cut-off.

valve and journaled concentrically to the acting-surface of said fast eccentric and arranged to turn around the same, whereby the rubbing surfaces between the two valves always remain the same, substantially as described.

3. The combination, with the shaft of an engine, of two eccentrics for operating the valves thereof, one of which is fast on said shaft and the other journaled concentrically to the acting-su rfaoe of said fast eccentric and constructed and arranged to turn around the same, whereby the rubbing-surfaces between the two valves remain always the same, substantially as and for the purpose specified.

4. The combination, with the main shaft G of an engine, and as a means of operating the valves thereof, of the eccentric H, fast on said shaft, and a loose eccentric, L, j ournaled on said fast eccentric and turning concentric with its center, whereby the rubbing'surfaces between the two valves remain always the same, substantially as described.

5. The combination, with the main shaft and valves of an engine, of the eccentrics H and L, the former fast on the shaft and the latter journaled on the eccentric H, concentric with the acting-surface thereof, the governor Q Q and S S, the links R, connecting the governor to the eccentric L, and the link J N,

ICC

connecting the eccentrics to the valves, substa'nt-ially as and for thepurpose specified.

In testimony whereof I afiix my signatnre,in presence of two witnesses, this 29th day of November, 1886.

GEORGE M. PELTON.

VVit-nesses:

CHARLES E. CLARK, J. N. HYDE.

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