US239492A - Ubi haskin - Google Patents

Description

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- U. HASKIN. 0111i 0ff M'ohanism for Steam. Engines- NO' 233,492.. PMBMQd March 29,188L

URI HAsKIN, on Pirrsene, PENNSYLVANIA,

PATENT. OrlrIClEtV Assiettes Tb HIMsELF, i

` 'JOSEPH DILWORTH, AND S. OVENS, 'OF SAME PLACE.

CUT-OFF MECHANISM FOR STEAM-ENGINES.

SPECIFICATION forming; part of Letters Patent No. 239,492, dated March 29, 1881.

` Application filed December s, issn. (Monet) Steam-Engines; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming part ot' this 'io specification, in which- Figure 1 is a longitudinal section through the steam-chest or'valve-box of a steam engine. Fig. 2 isa'vertical section of the governor ofthe engine and ofthe apparatus con- '15 llected therewith for operating vth-e cut-ott' i valves. Fig. 3 is a side view'ot the apparatus g shown in Fig. 2. Figs4 is a sectional view ot' l the liange ot' the stops 'and ot' the rail on which they ride. Fig. 5represents a steam-cushion 2o to receive the stroke of the: cut-oft'valves.

In the several figures like letters refer to the same parts.

V In the drawings, A is the steam chest in lwhich the slide-valve B works.l v a a' are steam-ports admitting steam to the two `ends ot' the steam -cylinderthrough the v corresponding steamways b b in the slidevalve.

c is the exhaust-port.

3o Theslide-valve is operated in the `usual 55 exhaust-port c. The steam-ports a a and exhaast-'port c on the cylinder are so situate in .f relation to the steamways b b' and exhaustwaye in the 'slide-valve that when the slidevalve is in the position shown in Fie. l, the

4o live steam iu the steam chest is entirelycut off from the cylinder.

In the slide-valve B are two small steams passages,ff, one on each side of the exhaustway c, and so placed that when the slide-valve 45 is in the position shown in Fig. I, and during so much of its stroke as the steam is cut oli' fromenterin geither end of the cylinder through ,the steam-ports a`or a', both of the steam- A passages fj" are in communication with the 5c' ports a and d', respectively. There is also an has a steamway, 7c, which connects at either exhaust-steam passage, g, in the slide-valve connecting with the exhaust-way e at t' and ex-` tending backward,andforward to the upper surface of theslide-yalve atftlwo points not far from the upper orifices 0f the Steamways b b', 55 respectively, the purpose ot', which will be hereinafter explained.

In a recess on the upper surface of the slidevalve B is placed the exchange-valve C, which i `6o end with the small steam-passages ff( in the slide-valve when their orifices coincide. The purpose of this exchange-Valve C is to admit a small amount of steam to pass from one end ofthe steam-cylinder to the other, for a very short time, when the live steam is cutoff, and just before thel slide-valve cllangestheA live steam from one end ot' the cylinder to the other as the stroke ot' the piston is nearly completed. The exchange-valve Gis kept in place by a stop, It, operated bya stem from the outside, or by two adjustable stops, one placed on either side ot'a projection from the upper side ot'fthe ezrchange-valve, said stops extending to the outside of the valve-chest A, so as to be set, by means ot' a screw or otherwise, either Vclose to the projection of the exchange-valve, in which'case they hold it rigidly in place, orij at a slight distance therefrom, so as to'allow of a slight longitudinal movement of the exchange-valve in the direction of motion of'the slide-valve. By this means the point of the stroke ot' the pistcn,atwhic`h steam is allowed to exchange from one end of the cylinder to the other, maybe adjusted with accuracy.

On the upper face of the slide-valve B and resting thereon are two cut-oft' valves,'D D', one placed at each end of the slide-valve. Each of these cut-off valves has a steamway, l l', ofthe same diameter as their corresponding steamways b b' inthe slide-valve, so that when either of the steamways l l,`in the eutoft' valves D D', coincides more. or less with the steamways b b in the slide-valve, they admit steam from the cavityof the steam-chest into the steamways b b', and when either of these latter coincides more or less with the steam-ports a or a live steam is thereby admitted into the-steam-cylinder 3 but when the steamways lor l in the cut-ofi' do not comloo municate with their corresponding steamways b or b' of the slide-valve the live steam is cut oli' from the steam-cylnder.

At the outer extremity of each of the two cut-oli' valves D D' is a cylindrical projection, m m', which` when the'cut-oi Ivalve is moved .by the slide-'valve to the end, gets stroke, en-

ters a cup or cup-shaped cavity n n in the 4end wallsl of 4'thejsteam-chest A. These cupshapcd cavities n n are jlust large enough to receive thefprojeetions mm' without friction, so that as either projection m enters its cup n it incloses certain amount of live steam,-

' which serves as a cushion, and prevents injury to the valve-chest from the stroke of the valve when itcomes in contact with the end of the steam-chest, by which itsl outward s-troke is limited. The inward stroke o'f the cut-ofi' valves DD' is limited by adjustable stops G G'.'

Although the cut-off valves D D' are not attached to the slide-valve they 'move with it during a part of its strokeumt-il their motion is arrested in either direction bythe steamcushion on their outward' stroke,or by theA stop 4Gr or G' on' their outward stroke. In orderv to e'ect this the under surface of the cutoff valves D D' is caused to adhere to the upl' per surface ofthe slide-valve by means of the l the slide-valve, as before described, the'end of exhaustion of steam from Abetween their contiguous surfaces, throughthe steam-passage g,`

communicating with theeXhaustpassage e and exhaust-port c, which causes the cut-ovalves DD' to be pressed down upon the slide-valve bythelive steam in the valvefchest A. As soon, however, as eitherof the cut-off valves D D', on its' inward stroke, comes in contacty with the stop G or G', its" motion is arrested,

the slide-valve B still continues its stroke;

and to avoid friction caused vvby the' cut-oli'.

valve being pressed down onto the sur-face of the stop G or G'v which comes in contact with the'cut-oi' valve D or D' is inclined, as also is the surface of the cut-oli' valve where they come together, the result of which is that the cut-oli' valve is raised slightly from its seat on the slidevalve, and steam is admitted between their surfaces, so that all frictional contact is avoided. 'From this construction it will be obvious that if the stops G G', being adjustable, are set farther apart they will reduce the 'inward stroke ofthe cut-oi'valves D D', and

stops Gr G' being moved outward the less steam will be admitted. The stops may therei fore be furnished with arms projecting through the side or top of the steamlchest, which, be ing connectedv with a right or left screw-rod passing through female screws in the projections, will enable the quantity of .steam sup- .proach each other, thus allowing of plied to the cylinder to be regulatedat-will by merely turning the rod connecting the stops G G'.

I have provided a means by which this j adjustment may be effected automatically by connecting the stops G G with the governor,

so that whenithe'amountof steam suppliedim creases beyond the -desired. limit the rising of the balls of the goverrtor' will cause the' stops to recede from eachvother, and thus reduce the supply of steam, and, lvice versa, if the supply of steam becomes too small the stops will apa larger supply.Y To e'ect this each of the stops G G' has an arm, p p', projecting toward and past `the middle ot' the steam-chest, one ou the upper andthe other on the under side of its stop'.

These arms p p' have cog-teeth o o o' o', which gear into al cog wheel or pinion, r, placed between them, so that the revolution of the pin ionJr in 'one direction moves the stops farther apart, and its revolution inthe othelrdirection brings them nearer together. l

1n order to prevent friction of the stops on q q', which rides in a way, s. (See Fig. 4.)v

The pinion r is keyed to a shaft, t, which passes through a stutiing-box in the side of the" steam-chest A. Onto the other extremity-of the shaft routside of the steamchest is keyed an eccentric frictionfdisk, H, (see Fig.2,) so that a partial revolution of the eccentric disk H will cause the stops G G to move toward or from each other, according to the direction in which the'disk turns. lAnother similar ec centric disk, I, (see 11`ig.2.)i's keyed to a shaft,

u, the bearings of the shafts t and u being' stationary. 'Between the eccentric disks H and I is placed a friction-roller,- K, which has los its bearing in a swinging' gear-trame, J, which has its center-of motion on `the fixed pivot j."

A The eccentric disks H and I are exactly alike in size and contour, so that, turning on their respective aies in opposite directions, their pe' ripheries are at all times equidistant. They are the reverse of cams .in theircfunction, for, instead of raising and loweringthe frictionroller K and parts connected therewith, they are acted upon by the roller K/and caused`to '..I i5 make a partial revolution in one direction or the other by the motion of the friction-roller K. The friction-disks are set with their peripheries not quite touching the periphery of the frictiou-- roller K. This is their normal relative posi# tion until, by accelerated or lesseuedspeed 0( the governor, the friction-roller is lowered or raised, in which case its periphery-comes in cam-disks, I or H, as the case may be. When this takes plaee,if the governor allows the roller K to rise into frictional contact withthe -contact with the edge of the lower or upper f' upper friction-disk, H, and the disk H, colfnmences to turn, and thereby the shaft t, to

which itis keyed, turns' the pinion r, so aste bring the stops G G' ofthe cut-oh valves nearer to each other, thereby allowing a longer in ward stroke of the cut-otfvalves D D', and edf p mitting more steam to the cylinder of thesteaw 9G the valves D D', each of the stops has a flange,

cesmea l 8 engine. If, on the other hand, the supply of steam becomes eXcessive,the shaft of the governor is depressed, the friction-roller K is brought in contact with the lower eccentricdisk, l, only, which causes the disk I to turn in the opposite direction on its axis u. This causes the upper disk, H, to turn also, although notin frictional contact withthe friction-roller K by means of a cog-whechc fu', on each ofthe shafts t uf ot' the eccentric-disks, which cogwheels gear into each other. \Vhenever the supply of steam ,is 'just suflicient and the governor-shaft neither rises nor falls, the frictionroller revolves out of contact with both disks H and I, and the stops of the cut-ott' valve remain at rest. i

The. revolution of the governor-shaft E is effected by a beveled pinion, w, on` its lower extremity, which gears into a corresponding beveled pinion, rv, on the shaft of the frictionroller K. A pulley, z, is secured to the shaft y of the friction-roller K, over which a band passes to another pulley,'which is revolved by the steam-engine in the usual manner. The beveled pinion w on the lower end of the governor-shaft E has a ange, c', which rests on the periphery of the beveled pinion performing the function of, a stop for the governor-shaft.

As before stated, the shaft y of the frictionroller K, bevel-pinion and pulley z has its bearing in a swinging frame, J. rlhis bearing is near the free end of the, swinging frame J, which rests upon the short end of a lever or steelyard, L, which hasits pivot at c. 0n the steelyard L is a sliding weight, W, so that as the weight is slid from or toward the fulcrum of levcrL, a greater or less upward pressure is exerted on shaft E `of the governor through the bevel-pinions 'x .and w. rlhe re-l volving shaft E of the governor has an enlargement at itsv upper end, which is, by the' upward A.pressure ot' the short arm of the lever (steelyard) L, pressedl np against the under side of the short arms g g of the lever-arms M M ot' the governor. As this upward pressjure on the revolving shaft E` is increased it tends to force downward the ball-arms M M of the governor, and -thus necessitates a greater rapidity of revolution ot' thegovernorarms, and consequently more steam to raise them; and as the lowering or raising of the governor-shaft acts on the stops G G of the cut-off valves D D', as before described, to separate them or bring them nearer to each other, so as to give less or more ,steam to the engine, so the increase ,of the upward pressure on the lower end of the governor-shaft, by means of the weight W, increases the efectivc power of the steam-en gine. In place of a steelyard and weight an adjustable spring or pulley and weight, or other equivalent device, may be employed.

` The peculiar advantage of-my improved de-4 vice for admitting steam to exchange from one end of the cylinder to the thr, at or' near am enabled to combine it with the use of a cut-off, which hitherto has not, so far as 1 `am aware, been accomplished 5' and, further, that by means of my exchange- `alve and its stops, by which the position of t. le exchange-valve relatively to the ports or steam-passages; of the slide-valve canl be adjusted, and a slight motion of the exchange-valve can be ei'eeted, I am enabled to regulate the particular point ofthe stroke of the piston at. which the exchange is cti'ected.

The relative operation ofthe slidevalve, cut-off valve, and exchange-valve will be seen by reference to figures.

When the parts are in the position shown in Fig. l the steam is entirely cutoii' from the i engine, and the slide-valve is `about to shift t by the pinion 'r this stoppage of the cut-ofi'- valve D" would notJ take place so soon, and a 4 wider opening would be permitted for the steam between l and b. Before the slide-valve B completes its stroke in the direction of lh'e arrow, the cut-ottl valve D (atthe other end" f the steam-chest) is arrested by the projeetil i tn entering its cup a, while the slide-valve moves on. On the return-stroke ot' the slidevalve, and before the piston of the engine has completed its stroke, 'the slide-valve, moving in the direction of the `double arrow, carries with it both of the 'cut-oli valves D` and. D', the passages] and b being in full connnunication. The steam is then cut ott' entirely from the steam-engine by the closing of the ports c c andshortly before the piston completes its stroke, and before steam is admitted through the steam-passages l and i) and port a into the cylinder, the exchange steam-,passages f' fin the slide-valve come in line 'with the steam-v way k of the exchange-valve U and allow steam to exchange from one end of the steam-cylinder to the other, thus supplying the exhausted end of the piston with a small quantity of live steam before the commencement oi' its ret'urn-' stroke. The exchange-valve (l bei/n g fixed by the stops h hf, the duration of'this exchange is only momentary. As the exchange-passages ff' in the slide-valve come in communication with the ports c a of the steam-cylinder before they come in 'communication with the steam-passage k of the exchange-valve, the time at which this exchange shall occur may be varied slightly by regulating the movementof the exchange-valve C, by means of the stop h. The exchange of steam having been 'et'- fected and the steam-piston having completed its stroke, the slide-valve advances farther iu y the direction of the double arrow, Fig. l, un-

- stop G, and the slidelvalvc,

is then brought, by the advance ofthe slidevalve B, over and in communicatonJvith the steam-1 ort a, while the com m unication between Aro of the disks.

steam-passages l and bis still partly open, and thus live steam is admitted from the steamehest through port a .into `the steam-cylinder. As theslide-valve further advances the communication between the steam-passages land bis closed before the steam-port a is closed by the slide-valve, by reason of the cut-oil' valve l) .being arrested in its motion by the stop G. A It is obvious that if the stops G and vGr were brought closer together the amount of steam admitted through the ports a and a 4to the st'eamlcylinder would be increased, while the time and extent of cut-ott' may stil-l be f varied at pleasure by regulating the motion of '-the slide-valve in the ordinary way.

In Fig. 5 is represented a steam-cushion,

whichvmay be used to prevent injury to the walls of the steam-chest from the. stroke of the cut-oli' val-ves in lieu of the projections m and cups n shown in Fig. 1.

D represents one end of the'cnt-oi' valve, in

which is a cylindrical cavity, @'Q''atrthe centerl of which is a recess which receives a short spiral spring,- c. A small disk or piston,s, works in the cylindrical cavity 'i'. having" an outwardly-projecting stem, d. The cavity ,i is covered at the end ofthe valve D by a per- -forated plate, e, through a central hole in which the stern d' passes, thus preventing the tilting Un the periphery of the disk 8' is a, groove, g', which allows the live steam inthe steam chest A, entering through the lperforations in the plate e to pass'into the cavity i back of the disk-'or piston s.

The operation of this device is as follows: Then-thc cut-ntf valve D or D is carried, by this stroke of the slide-valve B, to the end of its stroke, the stem'd, coming in contact with the casing of the steam-chest A, causes the disk s to be forced downinto its cavity i', and as the steam confined therein cannot immediately escape through the groovegitacts as a cushion and arrests the motion of the vcnt lozl' valve gently and without injury to the walls of the steam-chest. 0n the return-stroke of the valve D the spring c' forces the disk o`utward and allows the cavity i to be refilled with steam through the groove g.

1. The combination, with tlibeylinder of'a- I' .steam engine and its slide-valve, of a cut- Otf valve and exchangefvalve, and'stops whereby the relative action of the cut-off and .ex-

change "alves are regulated and adjusted, subf stantiallyas described.

2. The combination, with a slidevalve forl steam-engines, having steamways for connectl 'ing the steam-ports of the cylinder, of an ex changevalve fon` making and breaking the steam-connection between opposite ends ofthe cylinder, substantially as described.

3. The combination, with a slide-valve for steam-engines, of ajn exchange-valve for effecting a Steam-connection between the opposite" ends ofthe cylinder through steamways in the excl1angevalvc and slide-valve, anda stop or stops for adjustingl the posi-tion of exchange valve, substantially as described. 'P

4. In combination with the slide-valve of a steamfengine, the'ctit-otf valves, each having a separate adyusta'ble stop` for limiting and regulating the cutoff as well as the amount of steam'supplied to the engine, substantially as' and for the vpurpose described. v

5. The slide-valve, cut-ott'A valves, and ad-` .j'ustable stops for liinitin'g and regulating the cgt-olf and supply of steam to the, cylinder, in

combination with .the gye'rnorot a steam-en-l gine, and in terposed', gearing for the automatic adjustment ofthe stops`ot' the cut-ofi'` valves, substantially as described.

6. The combination of the eccentric-disks H I and their gearing, and interposed frictionroller k with the governor of a steam engine,

and with stops for regulating the stroke ofthe.

cut-olf valves, and with the cut-off and slide valves, substantially as described.

7. 4'.Ihe combination of a steeiyard and ,l weight or equivalent device with the governor y of a steam-engineand with adjustable stops operated by the governor forr gulating the stroke of the cut-ott' valves,- and with the slidevval-ve, substantially as and for the purpose hereinbefore described.

8. The steam-cushion consisting ot' the cavity i', disk s', stem d', spring c', and passage IOSl g', combined and arranged substantially as described.

In testimony whereof .I have hereunto set my hand.

Witnesses: URI HASKIN.

JOHN S. KENNEDY, JNO. K. SMITH.-

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