US140309A - Improvement in steam-engine valve-gears - Google Patents

Description

` c. ROGERS. Steam-Engine Valve-Gears. No. 140,309.

Patented .lune 24,1873.

` valve stem b.

UNITED STATES PATENT OFFICE.

CHARLES ROGERS, or ALLEGHENYLASSIGNOR To EIMsELF AND JAMEs A' A. HUTCHISON, OF PITTSBURG, PENNSYLVANIA.-

IMPROVEMENT IN STEAM-ENGINE VALVE-SEARS.

Specification forming part of Letters Patent No. 140,309, dated June 24, 1873 application filed January 6, 1873.

To all` whom it may concern:

Beit known that I, CHARLES ROGERs,'of Allegheny City, in the county of Allegheny Yand State ofPennsylvania, have invented a new and useful Improvement in Steam-En gine Valve-Gear; and I do hereby declarethe following to be a full, clear, and erract description thereof, reference being had tothe accompanying drawing makin g apart of this specifica- Ktion, in which- Figure l is a side elevation of an engine and pump, illustrative in part of my improvement. Figs. 2 and 3 are detached views in perspective, illustrative ofthe improved devices employed in the steam-chests. Fig. 4 shows `an enlarged vertical section of a part of the reversing devices taken in the pla-ne of the axial line of the valve-stem; .and Fig.,5 shows in perspective one of the wedge-endedblo'cks employed in Fig. 4.

Like letters of reference indicate like parts in each.

In the class of steam engines commonly known as direct-acting engines, where a ilywheel and crank are dispensed with, some means specially designed for the purpose are ordinarily required to complete the throw of the valve. My invention relates to means for accomplishing this end, and also to means for adjusting the valve to its seat and relieving it of a portion of the downward pressure of the steam.

To enable others skilled in the art to make and Ause my improvement I will proceed to de- .Scribe its construction and mode of operation.

A represents an ordinary steam-cylinder. It has the usual piston, the stem A' of which extends to and isconnected with a pumping-piston in the pump G, or connection may be made with any other device or machine for commu- The engine is of the classnicating power. known as direct-acting. B is the steam-chest. The valve b is operated backA and forth in the manner of the ordinary` slide-valve by the 0n this stem are the usual tappet-nuts b2. The piston-stem A carries the usual tappeti-arm g. On eachv side of the tappet-arm g I secure a spring, g', the upper 'ng-end of which will come between the upper end of the tappet-arm g and the. nut b2 on 'that side. The end of the valve-stem b1 opposite the valve b carries a piston, f, Fig. 4, on the upper and lower faces of which are the teeth e, which Iare of such form as to give 'a double inclinethat is, an incline from the apex each way in the direction of the motion of the stem b1. The box or case D which contains these devices also contains the blocks D',- each of which has avwedge-shaped end, as at d, and such ends bear against the teeth e and arepressed against such teeth' by springs d or other like means. The pistonf is capable of a limited longitudinal motion in its case, and is cushioned at its opposite ends on elastic seats or cushions j.

In operation the movement of the main piston brings one ofthe springs g against its nut b?. The spring yields partially or wholly, till,

4by the force thus brought to bear, the valve b receives that part of its motion which is ordinarily given to itvdirectly by the tappet-arm itself'. The devices are so adjusted with reference to each other that at this point the apexes of the teeth e will be brought against or carried past the apexes of the wed ge-shaped ends d, the inclines of the two sliding on each other and the springs d yielding to allow the retrocession of the blocks D. As soon as these apexes 4conne against or pass each other the elasticitypf the spring g comes into action to force the valve b forward through the remainder of its throw. The blocksD o'er then no resistance, but, through the springs d', actually cooperate with the springs g in completing the throw of the valve, and the springs d (of any desired form) may be made of such rigidity and elasticity that, in connection with suitable devices for lessening the friction of the inclines on leach other, they .will perform the function ofthe springs g and in such case the latter may be dispensed with; also, a single tooth, e, with a single wedge-ended block, D, may be used, as this will secure the end in view, though less perfectly than when the de valve-chest B and the slide-valve b are providedwith the usual larrangement of steam v and exhaust ports. To relieve the valve of a portion of the downward pressure of the steam, or, in other words, to balance-the valve, as it is called, I cover it with a top plate, a, which I cause to rest with the greater partof the v vertically by setting the side plates c forward l or back, which 1s done by means of set-screws c2. By this means the top plate a is' made to A cover the valve as tightly as may be desired, and at the same time the greater part of the downward pressure is sustained by the side plates c; and, as the valve or its seat or the under side of the top plate wears away, the devices may be readjusted at pleasure without even necessarily stopping the engine for that purpose. v

I prefer that the steam-ports should extend up through the valve, and that at the end of the valve-stroke the steam-port at that end should be uncovered, as at s, so thatl the cylinder shall take steam both under the valve, as at s', and also from above at s. I thus secure a large port-opening with a 'short throw.

To keep the top plate a'down I arrange between it and the steam-chest cover a a press`- ure-spring,V ef, of any suitable construction. Itsoperation is too obvious to require description.

Iam aware that spiral springs unconnected with the tappet-arm have been arranged on the valve-stem at the tappetnuts. The construction hereinbefore described is superior,

f however, in that the springs are `more easily removable and renewable, and their elasticity can be more accurately adjusted with reference'to'the pressure required to complete the throw of the valve.

What I claim as my invention, and desire to v secure by Letters Patent, is v l 1. The inexiblc tappet-arm g having the springs g attached thereto, in combination with the tappet-nuts, piston-stem, and valvestem of a direct-acting engine, arranged substantially as set forth.

2. The valve-stem b carrying and operating a piston, f, in the box or case D such piston having one or more double inclines, e, in com. binationkwith the wedge-shaped end or ends d of one or more blocks, D', and a spring or springs for pressing the 4block or blocksl to their work, the parts being relatively arranged substantially as .and for the purposes set forth.

3. The arrangement inside the steam-chest and outside the valve of the top `plate a. and adjustable side platesc, makin g with each other yaninclined joint, c', substantially as set forth.

4. The arrangement inside the steam-chest and outside the valve of the top plate a, whereby, in connection with ports s s', the valve will take steam past the end o'f the top plate, substantially as set forth.

In testimony whereof I, the said CHARLES ROGERS, have hereunto settmy hand.

CHAS. ROGERS;

\ Witnesses A. S.vN1cHoLsoN, G. H. CHRISTY.

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