US240792A - Valve-gear for steam-engines - Google Patents

Description

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the production of a reversing and speed-reg- Letters Patent No. 203,224, dated April 30, 1878, and No. 213,079, dated March 11,1879.

irregular surface may be brought opposite to while one-half of the sleeve or shaft gradually UNITED STATES PATENT OFFrcE;

HERBERT WADSVVOBTH, OF GENESEO, NEW YORK.

VALVE-GEAR Foe SPECIFICATION forming part of Letters Application filed March To all whom z'tmay concern:

Be it known that I, HERBERT WADSWORTH, of Geneseo, Livingston county, New York, have invented certain new and useful Improvements in Valve-Gear for Steam-Engines, of which the following is a specification.

The main object in my present invention is ulating valve-gear, adapted particularly to; be used with the mechanisms described in my The invention, however, is susceptible of wider application, the device in which the same is embodied being adapted for general use on steam-engines.

The purpose that I have in view is to regulate'the running of the engine without the intermediary of the steam-throttle, and by means of the valve-motion alone. To effect this it is to admit but little steam to act upon the piston, but to allow that steam to enter during the whole stroke. Similar but more extensive. steam admission will produce a greater pistonspeed. After higher speeds areattained it is desirable to cut off the steam and work it expansively. Theilistrumentality which I employ in order to obtain the valve-motion necessary to produce these effects is a rotating sleeve or roller of irregular shape, which is longitudinally movable, so that any particular section of its the feeler or other means which takes movement from the sleeve and transmits it to the steam-valve.

' The general form of the sleeve may be briefly described as follows Its periphery at the neu tral point, or that point at which no movement will be given to the steam-valve,is cylindrical. From that neutral point or belt its surface departs from the cylindrical, tapering or inclinin g lengthwise 'in reverse directions, so that increasesin diameter the other half will correspondingly decrease, these surfaces being those of two half or conical frusta, put together side by side, the base of the smaller frustum and the smaller end of the larger frustum starting from the same portion of the sleeve-via, the neutral point or belt. By this gradual increase in size of one half of the STEAM-ENGINES.

Patent No. 240,792, dated April 26, 1881.

25,1881. (Nomodel) sleeve and corresponding decrease in size of the other half, the throw of the steam-valve which is due to the sleeve) can be gradually increased until the valve is. opened wide for steam admission in each direction. When the conical surfaces are extended far enough to attain this point, then for the remainder of the length of the sleeve they become cylindrical, and from these cylindrical surfaces lead longitudinally gradually-widening cylindrical tracks of reduced diameter, which have the same radius as the neutral belt, and effect the cut-off to any extent desired in each direction of the valve movement, according to the parlc lar section of the sleeve placed opposite to h motion transmitting mechanism. Any suitable means can be employed to effect the desired longitudinal adjustments of the sleeve.

The nature of my invention, and the manner in. which the same is or may be carried into effect, will be understood by reference to the accompanying drawings, in which I have shown one form of inechanisincmbodying my invention.

Figure 1 represents so much of atwo-cylin der upright engine as needed to explain my improvement. Fig. 2 representsmwo side elevations of the speed-regulating and valve-operatin g sleeve or roller, there being ninety degrees or a quarter-circle difference between the two elevations. Fig. 3 represents various crosssections of the sleeve or roller. Fig. etis a side elevation of the valve-operating levers, with the sleeve or roller in cross-section. Fig. 5 is a view of a detail hereinafter referred to.

In the engine shown the valves are located, as usual, between the two cylinders A B. I have not deemed it necessary to show them, nor the feed and exhaust pipes and various other accessories of the engine, inasmuch as my invention considers only the valve-motion. To adaptthe reversing and speed-regulating sleeve 0 to this form of engine, I mount it on a rotating shaft, D, which has its hearings on one side of the engine support or bed], as shown. The shaft obtains its motion from the engineshaft E through an intermediate shaft, 1, and bevel-gearing 2 3 4 5, as shown, the arrangement being such that the sleeveshaft will re volve in unison with the engine-shaft.

Any

other ordinary or suitable motion-transmitting 'grees apart.

purpose. The sleeve is mounted on the shaft in such manner that while compelled to rotate with the shaft it may slide or move lengthwise independently of the latter, and to this end ity is united with the shaft, in the present instance, by a spline or feather and groove connection.

The longitudinal sliding movement of the sleeve may be obtained in various ways. The means shown in the present instance, as indicated at F, is the mechanism described in my Letters Patent No. 203,224, the piston-rods 6 of the small engine being connected to a collar, 7, encircling a cylindrical flanged neck, 8, on one end of the sleeve, as shown in Fig. 5.

1n the engine represented in the drawings the valve-motions are the same for both cylinders. As the cranks on the en gine-shaft are set at an angle of ninety degrees to one another, it will, for the purpose of actuating the valves, only be necessary to take off the movement from the sleeve at two points ninety de- For this purpose I make use of mechanism such as shown more particularly in Fig. 4. In this figure the two valve-rods are seen at a a. Valve-rod a straddles a horizontal lever or feeler, b, which is pivoted at b to the engine-frame and rests on top of the sleeve. Valve-rod a straddles the horizontal arm of an angle-lever, o, pivoted at the elbow c to the frame, and having its vertical feelerarm resting against the side of the sleeve. The portions of the levers which are in contact with the sleeve lie in a plane which intersects the sleeve at right angles to its axis. Under this arrangement it will be seen that both levers will be influenced always by one and the same portion of the sleeve, and that properly-timed motions will be imparted to the valve.

Having described in a general way the organization and arrangement of the mechanism, I now proceed to a more particular description of the sleeve, referring to Figs. 2 and 3.

The part of the sleeve midway between its two ends constitutes the neutral belt hereinbefore referred to, and is shown at w. When the valve-controlling levers are opposite this belt they have no movement and steam is shut off from the engine-cylinders. From this belt toward the left one longitudinal half of the sleeve gradually increases in diameter, as indicated at d in sections as y, Fig. 3, while the other longitudinal half gradually decreasesin diameter, as indicated in the same sections at e, the dotted lines in these sections, and also in sections.

2 a." y z, hereinafter referred to, indicatin g a circle of the diameter of the neutral belt. The face 01 will move each valve in one direction, and

the face 0 will move it to the opposite extreme,

as indicated in Fig. 4. Under this arrangement, as the sleeve is drawn along, the valves will be caused to open little at first and then wider-and wider until the ports open wide, the steam admission continuing during the stroke of the engine-piston, or thereabout. At this point each one of the acting curved faces e d is gradually contracted, there being formed from part of them curved faces w w, as seen in section 2, Fig. 3, which are struck from the axis of the sleeve with the same radius as that of neutral belt w, and the width of these faces can be gradually increased, and the width of the faces 6 d correspondingly gradually diminished, so as to obtain as much neutral face as may be necessary to cut off steam to any desired extent. In section 2, Fig. 3, each cutoff face to is one-fourth of the circle, and each acting face 01 0 also one-quarter circle. If the sleeve be moved so as to bring this portion of it opposite the feelers b c, it will be seen that each feeler as the sleeve revolves will successively be in contact with the face 01, which moves the valve to its full extentin one direction, then with face w, which brings the valve back to neutral position, then with face 0, which moves the valve the full extent in the other direction, and then with the second face w, which again brings it back to the neutral point. The other half of the sleeve to the right of the neutral belt is formed like the half just described, with surfaces d e w 10 corresponding to d c w to. When this half of the sleeve acts on the levers the engine will reverse.

The sleeve can be made of any suitable length. The longer it is the more gradual can be made the slopes upon it, and the more sensitive and delicate of action will be the controlling mechanism. It is manifest, of course, that with direct-acting engines, or with separate reversing-gear mechanism, the sleeve need not be made with acting surfaces to each side of the central neutral belt, but may be made like either half of the sleeve represented.

It is apparent that in some kinds of valve- -gearing the feelers, or their equivalents, may

be movable lengthwise of the sleeve, instead of the sleeve being movable.

1 do not claim, broadly, the use of a rotatin g and longitudinally-movable cam-sleeve for the purpose of operating the valve -gear of steam-engines nor do I broadly claim such a sleeve provided with cam-surfaces to each side of a neutral belt or zone. This I am aware is old; but I am not aware that there has ever before been devised for this purpose a sleeve or roller having the form and characteristics hereinbefore described, whereby, when the engine is to be started or run slowly, the piston is acted upon by but little steam, which, however, enters during the whole stroke, higher speeds being attained by similar but more extensive steam admission, after which the steam is cut off and worked expansively.

What I claim, therefore, and desire to secure by Letters Patent, is

1. In valve-gear for steam-engines, the combination, with the steam-valve and feeler, of a rotating speed-regulating sleeve having a surface of the form substantially such as described, and movable longitudinally with respect to the feeler, so as to bring opposite to said fceler that portion of its surface adapted to impart the desired movement to the valve, substantially as and for the purposes herein- IO substantially as hereinbefore set forth. before set forth. l

2. The rotating speed-regulating sleeve or In testimony whereof I have hereunto set roller formed with a central neutral belt and my hand this 24th day of March, A. D. 1881. with irregular surfaces substantially such as 5 described, to each side of said belt, in combi- HERBERT WADSWORTH' nation with the steam-valve and feeler, said Witnesses: I sleeve and feeler being movable with respect E. A. DICK, i y to one another longitudinally of the sleeve, N. 0. LANE.

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