US252224A - Steam engine valve geak - Google Patents

Description

4 Sheets-Sheet, .1.

(No Model.) Y

' D. JOY.

STEAM ENGINE VALVE GEAR.

Patented Jan. 10, 1,1882.

"('N'O Model.) 4 sheets-sheet 2.

\ D. JY4

l STEAM ENGINE VALVE GEAR.

224. Patented Jan. 10,1882.

mswN

s f 2.. 1@ f w N f nA PETERS. Phmiumugmpher. washing o, cA

(No Model.) A 4 4 sheets-sheet 3.

D. J OY.

STEAM ENGINE VALVE GEAR.

No. 252,224.` 'Patented-Jan. 10,l8'82.`

N. Pneus. Pwommgmpnr. wnhingmm D. c.

(No Model.)

D. JOY'.

.. `STEAM ENGINE VALVE GEAR.

4 Sheets-Sheet .4

Patented J zin. 10, 1882. f

N. Pfrzns. Pnmunhngnpner, washsngmn. u. c

By z's Aitor A. "UNITED 'STATES PATENT OFFICE.

' y DAVID JOY, OF BARROW-IN-FURNESS, COUNTY OF LANCASTER, ENGLAND.

S'TEAM--ENGINEY VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 252,224, dated January 10, 1882. Applicationled June 10, 1880. (No model.) Patented in England March 8, 1879'.

To all whom it may concern:

Be it known that l, DAVID JOY, of Barrowin-Furness,4in the county of Lancaster, Eng*- use of a simple form of valve-gear capable of givin gexpansive action or reversal to the valve or valves. The improved valve-gear in its preferred form is composed of a double lever the longer end of which is attached to any point stion of the valve-spindle joint.

of the connecting-rod. The fulcrum of this lever, instead of being fixed, traverses a slide which is centered at right angles, or nearly so, to the line of motion of the connecting-rod. This slide is capable of being angled to either side of the right angle. To the outer and shorter end of the said lever is Vattached the rod actu atingthe valve; or the center of the lever may be hung on a linkecntering at or aboutthepolt will thus be seen that the valve, being moved iirs't by a lever attached to the connecting-rod, is partaking of the movement of the crank; but this motion is modified by the movement of the fulcrum of the lever in the slide according to the `angle at which'that slide is set, and by a combination of their movements in various proportions all the positions required for various deg-rees of cut-olic and of reversal may be obtained.

' This motion,from its simplicity, may be applied to anyclass of engine, whether stationary,marine,orlocomotive. The slight inequality in the motion of the valve arising from the arc of the lever may be corrected by attaching I the end of the lever (described above as attached to the connecting-rod) not directly to the connecting-rod,but part way along another lever, the one end of which is attached to the connecting-rod, the other end slidingin a guide on the opposite side and at right angles tothe motion of the connecting-rod. The arcs made by these two levers crossing will correct each other and produce a perfectly equal action.

By varying the proportion of the levers and the slide action, and by varying the proportion of motion transmitted to the valve by each, any combination of lap and lead may be ohtained.`

To. apply this motion for working the valves of direct-acting pumps or engines where there is no rotary motion, a slight modification is required.; In this case the lever, actuated by theconnecting-rod 1n the rotating engine, is4 attached to the cross-head of the piston-rod, and has its fulcrum carried in a slide, as before; but'the angle of the slide is changed over from side to side either by mechanical action, as by the changing of the motion of the rod, bringing a thrust on the slide and throwing it over, or by a small cylinder and piston connected to it, this small cylinder receiving steam from the large cylinder.l Thus at each end of the 'stroke the steam admitted at lead to the i large cylinder passes over to the small cylinder showing my improved valve-gear applied to an overhead marine engine. Fig. 2is a detail view, showing the block in which the end ofl one ot' .theLlevers pivoted to the connecting-rod slides.

Fig. 3 is an elevation showing the improved valve-gear applied to another form of engine, and Fig. 4 is a half cross-,section of the same.

.Figs.5, 6,and 7 are detail views, showing moditiedforms of the gear. Fig.8 is a detail view of one form of the valve which is used in connection with the modification shown in Fig?, and Fig. 9 isa view of a direct-acting pumping-engine with the improved valve-gear applied A thereto.

Fig. 1 illustrates this valve-motion in its simplest and most perfect form as applied to an ordinary overhead marine engine. A lever,

a, lis centered at a. in a block, A, free to slide l in a curved slot-link, b, which is centeredat b', and free to be set at various angles to the horizontal. This lever ct receives motion :from the connectingrod C through a second lever or IOO a will therefore have a movement compounded,

or away from iton either side, according to the position and amountof movement required; or this action maybe taken directfrom the crank. This rod c, at the other end, is either allowed to slide horizontally in a block and slide, as shown in Fig. 2, or it is suspended by a suspending-` link, D, as shown in Fig. 1, and thus vbrates in a cross direction to the vibration ofthe connecting'rod. The point a2 at which the end of the lever a is jointed to this rod or lever c is such as to correct the radial error of the lever a and to cause its fulcrum to traverse the slotlink Z equally on each side ot its center; but while correcting this action it docs not reduce its amount. The lever c will therefore have imparted to it at the point a2 a vertical action,

while its fulerum will also be traversed horizontally and equally in the slot-link b, partaking also ot a motion due to the angle at which the slot-link may be set. The outer end, a3, of this lever, to which the valve-rod e is attached,

t of the up-and-dovvn lever action of the lever a and of a similar motion, but timed differently, caused by the fulcrum sliding in the slot-link I), and in proportion. to the predominanee'of A eithervot' these movements any lap, lead, or

port and any point of cut-ott may be arranged for.

It is evident that when the slot-link b is in the horizontal position the valve Will be moved onlyfor mid gear,77 and in proportion as it is varied from this position either way-forward or backward-motion will be given tothe valves with an opening of the ports of more or less duration and extent, according to the angle ot' the slot-link. Thus, with an action taken from theconnecting-rod,movementiscommunicated directto the valve, the radial action ot' the lever a being corrected by the rod c and the radial action of the valve-connectin g linke being corrected by the curvature ot' the slot-linkt, resulting thus in a correct action of the valve, giving equal leads, points ot' cut-oft, and openings of port for both ends ol' the cylinder,each

. of which, however, may be varied at pleasure either vvay by altering` the proportions of the parts and the point at which theV center of the lever a crosses the center ot' the slot-link b. The position ot' the slot-link is controlled to govern the forward and backward motion or amount of expansion by means ot' a Worm, as

shown in Fig. l.

Instead ot the center ot' the lever a sliding in the slotlink, it may be hung by a suspending-link, the upper end ot' ivhich is centered at such a distance and position as to canse the center of the lever a to traverse a similar path to what it would it' governed by the slot-link, the pointofsuspension of such suspending-link heilig adjustable, so as to allow the curves formed by its vibrating end to be the same as the curves of the slotted link in its various positions or angles.

To work a cut-oft valve on the back ot' the main valve, as is customary with an extra ec- `centric when the link-motion is employed, an

additional lever, like a, and a slot-link, like b, may be employed, the slot-link of the expansion-valve being set at the reverse angle to that of the main slide-valve, and being more or less angled, according to the amount of expansion required; or the levera may be lengthened at its outer end, (see Fig. 1,) and the expansion or cut-oft valve-rodf may be attached to this, with an adjustment for lengtheningv or shortening the stroke according to the expansion required, as shown in the drawings.

This gear, which is specially adapted for actuating slide -valves under high-pressure steam and the large and heavy valves ot' marine engines, which have a long stroke or traverse, all ot' which require great force to move them, is suitable to all engines requiring reversal and expansive motion, such as is now usually gained by the link-motion, and moditication ot' the parts will render itavailable Wherever the link-motion obtains. Thus, for locomotive, rolling-mill, and Winding engines, for agricultural and traction engines, Where the diameter of the cylinder bears a small proportion to the length of the stroke, I connect the rod c to a point considerably outside the center line ofthe connecting-rod, as shown vin Fig. 3, and thus I bring the centerline ofthe valve-spindle into suitable relation to the center ot' the cylinder, while I also obtain anv increased dnration of the maximum opening of the port toivard the end of its movement. In Fig. tis shown a halt' cross-section of the same engine.

Retaining the general principles ot' this gear, its arrangement may be modified, as in Fig. 5, where the lever a is pinned directly to the connecting-rod, astraight slot-link, b, is used, and the errors arising from such changes are balanced against each other by setting the ccnter of support b, on which the slot-link is angled, out of the center line ot' the slot-link, as shown; or .the corrections ot' the radial action of the lever ct and of the valve-rod c may be effected by carrying the center ot' the slot-link b in a horizontal slide and moving it backward and forward each stroke by the amount ot the above-named radial errors 5 and again, as in Fig. 6, the lever a may be exchanged for a bell-crank lever and a connecting-link, a, the action of this bellcrank at each change of motion of the connecting-rod being controlled by a cataract-cylinder, or by a spring, as shown in the drawings; or again, as in Fig. 7, the center of the lever a, or of the bell-'crank a3, may be stationary in the slot-link, (its position therein governing the forward or backward motion and the amount of expansion,) and its inner end receives one motion from the connecting-rod, while the other motion is supplied by tlie slot-link itselt' being vibrated by its attachment to the cross-head or connectingrod; or the slot-link may be apart of or may be txed to the usual air-pump levers, which already have the required motion from the lOO lIO

cross-head; or if in any instance it is found convenient to attach the valve-rod within the fulcrum of the lever, as shown in dotted lines, Fig. 7, then as the action communicated to an ordinary slide-valve would be exactly opposite to that required, I employ in such'case a double D-valve admitting the steam past the lip of the port-face at m, as shown at Fig. 8, instead ofthe usual slide-valve.

Other modifications may suggest themselves to those skilled in the art without departing from the spirit of my invention.

The application of the main features of this valve-gear to direct-acting pumping-engines is shown in Fig. 9. Here the lever a receives motion from the cross-head, both as alever and as sliding its fulcrum in the slot-link b; but as both the inward and outward strokes of lthe cross-head are similar, it is necessary to change the angle of the slot-link for each opposite stroke. This is done by a small steam or water cylinder at a, controlled by a cataracteylinder, which may be one with it, as shown; or the steam-cylinder may be made to serve hoth purposes by making its ports of such capacity that they will contain sufficient water or uid to fill the cylinder at each stroke, and the Water or Huid would then nearly all pass backward and forward through the cylinder and ports. The piston-rod ot this small cylinder is connected to either end of the slot-link, as is convenient, and the steam may he admitted to it either by the main valve or by a small independent valve; or the slot-link may be pushed over by the thrust of the lever ci on its return movement at each end ofthe stroke of the piston, a suitable locking-catch beiugprovided to hold it over till the opposite end stroke is required, when the position of the lever a, unlocking this catch and reversing its pressure on the slot-link, would again push it over to its other position. y

I am aware that English Letters Patent No. 3,17()A of 1875 show an engine in which a valve-rod is pivoted to and operated by a lever which is actuated by an eccentric on the main shaft, the end bearing of said lever sliding in a grooved or slotted pivoted block. I

Vmake no claim,I therefore, to the construction shown in such patent.

Having thus described the nature of my said invention and the manner in which it may be used or carried into effect, what I claim as new, and desire to secure by-Letters Patent, is

1. The combination, in an engine, of the valve-rod, the vibrating' operating-lever pivotally connecte'd to the connecting-rod and to the valve-rod, the pivoted link in which said lever is fulcrumed, and mechanism for controlling the positionf of the link, substantially as and for thepurpose set forth.

2. The combination, in an engine, of the connecting-rod, the valve-rod, a lever-connection between said rods, anda pivoted slot-link which carries the fulcrum of the lever-connection, substantially as and for the purpose set forth.

3. The combinatioinin an engine, of the connecting-rod, the valve-rod, the lever-connection a between said rods, the sliding fnlcrum of the lever-connection, and the pivoted slotlink in which it moves, substantially as set forth.

4. The combination of the valve-rod, the connecting-rod, the lever c, pivoted thereto,k the lever-connection a, its sliding fnlcrum, and the pivoted slot-link in which the fulcrum slides, substantially as set forth.

5. The combination of the connecting-rod C, the valve-rod e, the cut-off valve-rodf, the lever-connection c, its sliding fulcruni, andthe pivoted slot-link, substantially as and forthe purpose set forth. Y

6. Theim proved valve-gear, `consisting of the vibrating operating-lever pivotally connected to the reciprocating cross-head or eonnecting-

Images