US281122A - Valve-gear - Google Patents

Description

(No model.)

1 A 3 Sheets-Sheet l. E'. OGDEN.

, VALVE GEAR. No. 281,122. Patented 'July 10, 1883.

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3 Sheets-Sheet 3.

(No Model.)

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VALVE GEAR. No. 281,122. f Patentedluly 1 0, 1883.

UNITED STATES PATENT EEnnrs OGDEN, `or MOUNT vEnNoN, OHIO.

VALVE-GEAR.

SPECIFICATION forming part 0f Letters Patent NO. 281,122, dated July 10, 1883.

Application filed January 3l, 1883. (No model.)

To @ZZ whom, t may concern:

Be it known that I, Fnnnrs OGDEN, of Mount Vernon, in the county of Knox and State of Ohio, have invented certain neW and usefullmprovements in ValveGear; and l do hereby declare the following to be a full, clear, and exact description of the invention,

such as will enable others skilled in the art to j the steam chest, and through a guideway which it pertains to make and use the same.

This invention relates to that class of automatic cut-off valve-gears in which the cut-off mechanism is controlled by a governor' re-v` volving With the fly-Wheel shaft.

The obj ect-s of my invention are to providev a simple and reliable adjustable connection; between the cut-off valves and the governor; to enable the cut-ofi to take place at any pointI between the initial opening of the main valve and thecompletion of its full stroke; to give 'the cut-ofi' valves a quick motion at the moment of cutting oft' the steam, thus avoiding Wire-drawing and sluggishne'ss of theregulation, and to obviate uneven Wear of the cut-offvalve seats.

Figure 1 is a perspective view of a steam engine provided with my improvement, the` cylinder, piston, steanrchest, and valves being shown in horizontal section on aplane cutting the diameter of the cylinder. Fig. 2

is a plan view of the engine, With the same which is iixed upon the main driving-shalt C.

D is the steam-chest, having steam-passages d d connecting with ends of cylinder.

E is the main steam-valve, having entryports e c at its opposite ends, the portion of said valve between these ports being hollow, and having in its bottom Wall. the transverse exhaust-portsf fand the main longitudinal exhaust-port g, (see also Fig. 4,) which is in communication Withthe exhaust-passage g in .the shell ofthe cylinder, and with the apertures f f through the cavity ofthe valve. The peculiar function of this arrangement of the exhaust-ports will presently appear.

E is the main-valve stem, which is tubular, and connected at its inner end with a block, e', which lits between lugs projecting from the back or the main valve. This stem plays through the usual stufling-box at the end of formed in a bracket, e, attached to the frame supporting the cross-head Ways; or it may be supported in any other convenient manner.

From the tubular stem E a stud, e3, projects at a point between its bearings, and to this stud is pivoted the eccentric-rod or pitman H', which at its opposite end is connected in the usual manner With the eccentric h, iixed uponthe main shaft C, this eccentric being adjusted .to cause .the main valve to bring its ports at proper times in coincidence with the steam-passages d d.

I is the sliding cut-off valve, which has its seat upon the back of the main valve, and is of such length that when one of its ends just closes the entryport at one end of the main valve its other end Will have just uncovered the entry-port at the other end of the main valve. The sliding cut-off valve has an opening formed through it, to accommodate the lugs and block at the back of the main valve, andV is itself provided with lugs, between which lits a block, I, to which is attached the cutoff-valve stem I', which plays through the tubular stem E of the main valve. This cut off valve stem I projects beyond the outer end of the tubular main-valve stem, and has its projecting end pivoted to one end of a short pitma-n, K, the other end of which is pivoted upon a crank-pin projecting from a disk, K, which is iixed centrally upon the end of a short shaft, K2, which turns in a single bearing formed for it through the eccentric-rod or pitman H, and carries at its opposite end a gear-wheel, L. This gear-Wheel L meshes with another gearvhecl, M, which is mounted eccentrically upon the main shaft O, and has its eceentricity coincident with that of the eccentric 7L, in order that its engagement With the wheel L may be constantly maintained. This gear M has a peculiar construction, which enables its toothed face to be adjusted about IOO its center, while the wheel,v as a whole, retains its eceentricity upon the main shaft.

Referring to Fig. 4, the letter m indicates a circular disk or cylinder which forms the interior portion of the gear m', and is fixed eccentrically upon the shaft, and n indicates a loose toothed ring whichY fits concentrically upon the periphery of this disk.

It will be readily seen that when the toothed ring is turned independently of the disk motion will be communicated to wheel L, and through intermediate connections to the cutoff, without regard to whether the main shaft and main valve are in motion `or not, and by moving said toothed ring, when the engine is in operation, it will be obvious that the move'- ment of the slide-valve with relation to the movement of the main valve will be varied, so that the cut-off will occur at an earlier or later portion of the stroke of the main valve. In order to adjust this toothed ring automatically so that it will cause the cut-off to occur at proper times to regulate the engine, it is connected with a governor7 the arms O O of which are pivoted to spokes of the fly-wheel W, and connected by springs p p to the periphery of anl adjustable collar, q, which is fitted to turn upon a hub or boss of the flywheel, and is held in position by a set-screw, q. The governor-arms are respectively connected by links r r with the opposite ends of an equal-armed lever, S, pivoted upon the main shaft O, and one arm of this lever is connected by a pivoted link, t, with the edge of the toothed ring. Vhen the governor-arms are at their innermost position, the parts will stand, say, as shown in Fig. I-that is, so that the cut-off will be about to take place at the completion of the instroke of the piston, this being, in effect, no cut-off at all, or a zero-point in the movement of the cut-off valve, the two valves being in similar or same relative position at the end of the outstroke. When, however, the governor-arms are thrown outward-say to their fullest extent, as is supposed to be the case in Fig. Z-the toothed rim M will have been turned in the direction indicated by the arrow numbered l, the wheel L and the crank K in the direction of arrow numbered 2, and the out off valve thrown forward, so that the eut-off will take place immediately after the steam-entry passage d is opened. Ihese are the extreme opposite points of the stroke and cut-off, and it will be obvious that when the governor-arms hold any intermediate positions between the two referred to the cutoff will be regulated accordingly-that is, in accordance with the varying speed of the engine as its load or duty is lessened or increased. By adjusting the collar q to the right or left the tension of the springs p p may be varied, and the divergence of the governor-arms under given speeds and the motion of the engine under given steam-pressure regulated as desired. Y

In steam-engines having slide-valves controlling both steam and exhaust ports it has heretofore been impracticable to cut off the steam earlier than at about two-'thirds stroke, on account of the effect produced on the valve by the disproportion occasioned between the pressure in the steam-chest and the exhaustcavties of the valve, these cavities being necessarily so large, in order to give sufficient exhaust, that the counter-pressure \under the valve is withdrawn to such an extent as to necessarily increase the load on the valve.

By using the hollow main valve with its longitudinal exhaust-port I am able to keep this port always open, and can` therefore reduce its area to such an extent that while the exhaust may be ample there will always be sufficient pressure under the valve to counteract to a great extent the pressure of the incoming steam upon the valve. Such a main valve, it will be seen, renders practicable the use of my cutoff gear, giving its extended range to the cutoff valve.

It will be observed that although the cut-off valve varies the point of cut-off it necessarily makes a full stroke at every revolution of the wheel L, and therefore traverses the seat from end to end, so that there will be no uneven wear or hollowing of said seat. The cut-off-valve stem and pitman are connected to the crank-disk K2, as will be seen by reference to Fig. l, so that the cut-off takes place when the crank is on the quarter, or that part of :its revolution which transmits the most rapid movement to the valve, so that the cutoff will be quick, with no tendency to wiredrawing of the steam or lack of promptness in the regulation of the speed of the engine.

I wishit to be understood that while I prefer to use the construction shown in .my drawings and heretofore described I do not limit myself to connecting the governor with the iiywheel, as it may be supported by radial arms on the main shaft, and the adjustable collar to which the springs are attached may be placed directly on the shaft, or a disk or cylinder fixed thereon. N or do I confine myself to the tubular main-valve stem, and the cutoff-valve stem playing therethrough, as the cut-off-valve stem may be caused to play through a separate stuffing-box; also, the construction may be varied by substitutin g belt-pulleys and a belt in lieu of the gear-wheels L and M, the pulley on the shaft having an adjustable rim, andI reserve to myself the right to modify any of the parts or combinations of parts, with a view to the more perfect embodiment of the essential principles of my invention.

I make no claim in this application to my improved valve, but reserve said subject-matter for a separate patent.

Having fully described my invention, whatI claim as new, and desire to secure by Letters Patent, is

l. In a steam-engine, the combination, with a sliding main steam-valve, having entry-ports at its opposite ends, of a sliding cut-off valve IOO IIO

5 justable connections communicating motion to seated on the back of said main valve, and having a range of variation of cut-ofi' extending from the beginning to the end of the piston-stroke, and intermediate automatically-adsaid cut-off valve from the iiy-Wheel shaft of the engine, substantially as described.

2 The combination, with the main Valve, hollow stem, and an eccentric-rod or pitman connecting said stem With the main shaft, and the cut-off valve and stem, the latter being located in the hollow stem of the main valve, of a shaft journaled in the eccentric-rod or pitman, and carrying a crank connected with the stem of the cut-off valve, and means for comnmnicatin g rotary motion to the'said shaft from the main shaft, substantially as set forth.

3. The combination, with the main slidevalve, its stem, and pit-man connected with the main shaft, and the cut-off valve and its stem, of a shaft journaled in said pitman and having crank-connection Withthe stem of the cutoii valve, intermediate devices for communicating rotary motionto said shaft from the main shaft, and a governor operated by the main shaft and connected with said shaft carried by the pitman, for varying its relative revolution with respect to that ofl the main shaft, substantially as described.

4. The combination, with the main shaft, main valve, its stem, and the pitinan connecting said stem with the main shaft, andthe cutoff valve, its stem, andthe shaft journal'ed in 1 said lpitnrian and connected by crank and pitman with said cutoff-valve stein, oi' a gearwheel carried by said shaft jonrnaled in the pitman, a gear-Wheel engaging therewith, mounted eccentrically on the main shaft, and having its toothed face adjustable about its own center, and an automatic governor operyof the cut-off relative to that of the main valve,

substantially as set forth.

6. The combination, With the main valve and pitman for actuating it, of a cut-off valve, a crank and gear mounted in said pitman, devices connecting the crank and cut-off, a gear supported on the eccentric of the main shaft and meshing with the gear on the pitman, and a governor on the iiy-Wheel, for varying the position of the crank, substantially asset forth.

In testimony whereof I have si gned this specication in the presence oftwo subscribing witnesses.

FERRIS OGDEN.

, Vitnesses:

S. G. NOTTINGHAM, GEORGE COOK.

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