US422769A - Island - Google Patents

Description

2 Sheets-Sheet 11.

(No Model.)

N. T. eEEENE. LIBERATING VALVEGEAR FOR ENGINES. 10.422.769

Patented Mer. 4, 1890.

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N. T. GREENE. LIBERATING VALVE GEAR FOR ENGINES. No.l 422,769. Patented Mar. 4, 1890.

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. UNITED STATES- PATENT OEEICE.

NOBLE T. GREENEQOF PROVIDENCE, RHODE ISLAND.

LIBERTING VALVE-GEAR `FOR ENGINES.`

SPECIFICATION forming part of Letters Patent No. 422,769, dated March 4` 18490.V

Application led October 2l, 1889.` Serial No.327,692. (No model.)

To all whom it may concern.-

Be it known that I, NOBLE T. GREENE, a citizen of the United States, residing at Providence,in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Liberating Valve- Gear for Steam-Engnes'; and I do hereby declare the following' to be a full, clear, and eX- act description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters of reference marked thereon, which form a part of this specilication.

The improvements forming the subject of my present application relate to liberating valve-gear for steam-engines; and it consists,

essentially, of a transverselynrranged selfclosing ,slide-valve, a valve-rod carrying a governor-controlled latch, and a tappet operating crosswisc of the cylinder, all as will be fully hereinafter set forth and claimed.

The object I have in View is to provide automatic cutoff engines with an improved liberating valve-gear arranged to operate the steam-valves crosswise of the cylinder.

By means of my improvements the several adjustments of the valve-gear maybe readily eifected.

In the accompanying two `sheets of drawings, Figure l, Sheet l, is a side elevation of a steam-engine cylinder provided with myl improvements viewed from the back side, the cylinder having crosswise working slide valves. Fig. 2 is a transverse sectional view taken on line @c of Fig. l. Fig. 3, Sheet 2, is a side elevation viewed from the rear side thereof, showing in reduced scale the cylinder, valve-gear, and governing and driving mechanism therefor. Fig. 4 'is a side view, inpartial section, of an ordinary gridiron or register slide-valve-that is, a valve having multiple ports. Fig. 5 is a transverse sectional view taken on line o o of Fig. 4. Fig. 6 is a side view of the wedge or lifter-block directly actuated by the governor.` Fig. 7 is a cross-sectional view of the exhaust-valve and its seat. Fig. 8 is a side view, in partial section, of the exhaust-valve. Fig. 9 is a similar view of the ported covering-plate for the valve. Fig. l0 is an end view of the plate.

Fig.A ll is a longitudinal sectional view of a clutch adapted to reverse the engines movement. Fig. l2 is an end view, and Fig. 13 is a partial end view, of the cylinder, in reduced scale, showing a weight or dash-pot of usual construction for closing the steanrvalve. j

The general construction and arrangement of the cylinder, frame, pillow-blocks, main shaft, and other parts of the engine, excepting the liberating valvegearand the lnanner of operating the same, are substantially the same as common to engines of this class or type. Therefore I deem it unnecessary to more specifically describe such common parts in detail.

The following description refers more particularly to my present invention.'

A, referring again to the drawings, desig nates a steamiengine cylinder as a whole provided with register-valves and seats.

n is the steam-chest, and m4 the exhaust chest, the former having the series of portopenings o', the latter having the large port m3. As drawn, the exhaust-chest is bored out to receive the seat t, provided with ports z', the seat itself being planed out to receive the valve r, which in turn has a series of openings or ports e, which coincide with those of the seat. To the top of the valve is tted a stationary coveringplate e", having openings e', all as clearly shown in Figs. 2. and to lO.

The exhaust-valves are actuated by an eccentric e', secured to a mounted shaft f, revolving in unison with the main shaft 0f the engine. The eccentric is jointed to an arm or lever l7', secured to the rocker-shaft f',

mounted in bearings at the ends of the cylinder. Near each end of the rockenshaft is secured a short lever c", which, through the medium of a link c4 and valvestem c", secured to the valve, reciprocates the corresponding exhaust-valve crosswise of the cyl-- e close the steam-valve upon being released by the valve-gear about to be described. Obviously the valve-stem is prevented from turn-` ing on its axis by being rigidly secured to the valve n', or by other suitable means. The valve-stein thus travels to and fro across the cylinder through the stuffing-boxes without turning, similar to a piston-rod. At the rear end of the stem is secured a head h, which is planed out to receive a steel sliding piece or latch l), adapted to slide up and down therein and resisted at the top by the pressure of a guided small spring p. To the latch is secured a pin d,whieh extends rearwardly therefrom and rests upon the cam or wedge-shaped block w, adjust-ably secured to a guided rod g, controlled and actuated by the governor t, all as clearly shown. The distance between the adjacent faces of the head h and cam w exceeds somewhat the extreme movement of the valve.

The eccentric-carrying shaft f and the rockcr-shaft f are mounted in bearings formed in brackets or extensions d, projecting from the rear side of the cylinder. The shaft f is driven through the medium of the main shaft S, toothed wheels B B, and the miter-gears D. (See Fig. 3.) At or near the ends of the cylinder and contiguous to the latches Z2 are mounted stationary studs 7c, each carrying a lever c, provided at its upper side with a steel tappet Z, the face of which engages the lower portion of the latch b. A vibratory movement is imparted to the tappet-lever c by means of an eccentric e, secured to the shaft f, the eccentridstrap being jointed to the lever, all as clearly represented in Fig. 2. I would state that I prefer to so arrange the latch and stud 7c with relation to each other that the working-face of the former stands directly in line with the axis of the latter when the steam-ports are closed, the face of the tappet Zat the same time just engaging its latch, while the corresponding eccentric c is on its dead-center.

The regulation of an engine provided with myimprovedvalve-gear is eected substantially as common-that is to say, the vertical movement of a fly-ball governor t, Fig. 3, is

vObviously now as the speed of the engine increases the governor-balls in their revolutions depress the lever t4, thus carrying the rod g ahead or in the arrow direction, Fig. 6, and consequently lifting the latches b against the resistance of the springs p and resulting in a short-er cut-off, an extreme of speed lifting the latches to such an extent as to allowl the tappetsto vibrateclear of them, thus preventing the parts from hooking on.

In Figs. ll and 12 I have represented an arrangement for reversing the engine or changing the direction of rotation. This is effected by withdrawing the loose half u of the clutch u from its fellow u2, mounted upon a shaft f, consisting of two pieces, and then turning the crank-shaft around the desired distance, or that portion of the shaft fhaving the several eccentrics secured thereon may be correspondingly revolved, after which the said parts u u2 are reclutched. If necessary, the eccentrics may be loosened and reset in addition. As this manner of reversing an engine will form the subject of a subsequent application for United States Letters Patent to be led by me, Ido not deem a fuller description thereof necessary to the present specification.

Assuming now that a cut-od engine having slide-valves'working crosswise of the cylinder beprovided with my improvement, the operation is substantially as follows: Motion is given to the valve-gear shaft f by means of suitable gearing, che., Worked directly from the main shaft. `Each steam-valve is operated by an independent' short-stroke eccentric e, adjustably secured to the shaft j', thereby vibrating the tappet Z a uniform distance at each revolution of the engine. An advantage derived from such construction is that the steam-valves may be kept open during the full length of the stroke of the piston, as well as permitting of the shortest cut-off. By means also ofthe individual eccentrics it is evident that the steam valves may be so set as to correct any peculiarities in the cylinder, such as compression, lead, &c. rlhe face of the tappet Z engages the outer face of the sliding latch b at its lower end, (see Fig. 2,) the latter being so adjusted that the degree of contact will be sufficient to completely open the steam-valve before unhooking. Immediately upon thus releasing the valve the latch will be'forced rearwardly past and over the tappet by means of the weight p2, thereby quickly shutting off the steam from the cylinder, the valve nowbeing in its normal or stationary position. The continued movement of the eccentric e carries the tappet back to its normal position, asin Fig. 2, the tappet in its rearward movement passing under and lifting the latch, which instantly drops to its limit by the action of the spring p. The maximum downward movement of the latch may be regulated by an adj listing-nut p4 at the upper end of the latchs stem. Obviously the rela- IIO tive vertical position of the tappet to the latch is mainly controlled by the governor through the medium of the tri pping-block w and the pin d, secured to the latch, a long cutoff maintaining the latch and tappet in contact through a much greater arc than a short cut-off, the former position corresponding, say, to Fig. 6, whereas for the latter the block w. would be advanced in the arrowr direction, thereby preventing the pin d-t`. e., the latchfrom falling so far. The pin, as before stated, slides back and forth transversely of and resting upon the block in unisonwith the valves movement, the relative position of the block being automatically changed by the governor, as common, according to the load imposed upon the engine.

The exhaust-valves are operated by a single eccentric c', adjustably secured to the rocker-shaftf.

It is no doubt generally understood that in engines of this class or type the several valves and connections are so arranged that both steam orboth exhaust valves are not open at the same time. The regulation may be effected by a ily-ball governor, as common, a weight or dash-pot being employed to cut off `the steam by the closing of the steam-valve upon the release of the latch by the oscillating tappet.

It occasionally happens in operating automatic cut-off engines that .it may be desirable, owing to a temporary derangement of the valve-gear, to `run the engine by a fixed or positive cut-off. I am enabled by means of my improvements to readily'accompli'sh y this result through the medium of the adjust-ing nut or nuts 234, or other equivalent means attached to the upper end of the latch b, thereby limiting the elevation or movement of the latch, the blocks w in such case being removed. NVhen thus arranged, the tappet acts to open the valve and the weight p2 to close it. Unscrewing the nut increases fthe vertical movement of the latch and produces a longer cut-off, screwing down the nut obviously shortening the point of cut-off.

Vhat I claim ism l. The combination, in a cut-off steanrengine provided with exhaust-valves Working crosswise of the cylinder, of self-closing steam-valves, also adapted to work transversely of the cylinder, self-dropping latches amount of their lvertical movement, and eccentric driven pivoted tappets vibrating transversely of the cylinder engaging the lower end of said latches to open the steamvalves.

2. The automatic detachable valve-gear for steam-engines, substantially as hereinbefore described, the same consisting of two selfclosing steam-valves working transversely of the cylinder, valve-rods having said valves secured thereon, a head secured to each rod, a self-droppinguor spring latch mounted to travel vertically in each head and at the same Ytime traveling to and fro in unison with the steam-valves movement, tappets mounted to vibrate on stationary pins, continuously-revolving eccentrics vibrating said tappets to `uncover the steam-ports, and governor-controlled tripping-blocks or cams directly engaging the latches, for the purpose specified.

3. In an automatic .steam-engine having steam and exhaust valves adapted to Work transversely of the steam-cylinder, the combination of a mounted eccentric-carrying or valve-gear shaft parallel with the axis of the engine and revolving in unison with t-he crank-shaft, two steam-eccentrics adjustably secured to the valve-gear shaft adjacent to the steam-valves, pivoted tappets transvversely vibrating by means of said eccentrics,

governorcontrolled self dropping latches` mounted in heads secured to the steamvalve stems and engaging the tappets, an exhaust-eccentric adjustably secured to the valve-gear shaft, a rocker-shaft actuated by means of the exhaust-eccentric, and levers secured to the :rocker-shaft and jointed to the NOBLE T. GREENE. lVitnesses: c

CHARLns I-IANNIGAN, ALBERT W. DAKIN.

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