US11223A

US11223A - Regulating the motiou of -steam-ehgihes

Info

Publication number: US11223A
Authority: US
Publication date: 1854-07-04
Anticipated expiration: 1871-07-04

Description

W.C. HIBBARD.

STEAM ENGINE.

No. 11,223. Patented July 4, 1854.

m: nonms PETERS o0. PHOTOLITNOH WASHINGTON n. c.

v UNITED STATES PATENT oFFroE.

WILLIAM CpHIBBARD, OF BOSTON, =MASSA GHUSETTS.

REGULATING THE ivro'rrolv or STEAM-ENGINES.

- Specification of Letters Patent No. 11,223, dated July 4,, 1854,.

To all whom itmag concern a Be it known that I, WILLIAM C. HIB- BARD, of Boston, in theicounty of Sulfolk and State of Massachusetts, have invented certain Improvements in Steam-Engines; and "I ;do hereby declare that the following is a full, clear, andexact description'of the constructionand operation thereof, taken in connection with the accompanying drawings, making a part of this specification, in which-- a i Figure 1 represents a sidelview of the frame and some of the parts of a horizontal engine; Fig.2 is an elevation of the crank end of the. same showing the arrangement of the regulator or governor in connection with my improved eccentric as applied to work the expansion or cut off valve; Fig. 3 is an elevation ofthe cylinder end of the same and Figs. 4, 5and 6 are separate views of my improved eccentric drawn to -a larger scale to show moreclearly its construction,

Figs. 7 and 8 are diagrams explaining the principle of its operation andits application to difl'erent valves. i

The firstpart of my invention relates to the mode in which I construct an eccentric for working the valves of steam engines; wl1ich I call an'isochronal eccentric; which is more particularly adapted to theyworking of,

expansion'or cutoff valves of various kinds;

and has the property of so moving the valves as that they shall admit steamatany constant point in the revolution or stroke ofthe engine, while theipoint of cutoff is made variable and vice versa. This iseffected by varying theeccentricity of the eccentric in the manner to behereinafter described.

The second part of my invention relates to the regulationof the-velocity of steam engines, by varying the point of cutting off the steam; and consists in combining agovernor or regulator with the isochronalQeccentric which works the cut-0E valves, so that the action, of the governor shall increase -or diminish "the eccentricity thereof and thereby so move the valves as tovary the quantity of steam to be admitted at each stroke, and thus regulate the velocity of the n The principle of the construction of my improved eccentric and its application to different valveswill be more readily seen byreferring to the diagrams Figs. 7 and'S. InEig. is'shown the theory of its applicationto a gridironslide -so called, when the steam passes through ports in the valve and corresponding ports in its seat.

A "represents the center of the main shaft of a steam engine; B and C the dead points of the crank; D one of the ports ofthe slide and E the corresponding port in the seat. The valve'and crank each being supposed to move in the direction of the arrows. In this position the valve is at the point ofopening, and the piston is at the commencement of the stroke, and the steam will be admitted while the port of the valve is passing over that of the seat. If the radius of the eccentric which'moves the valve be made equal to the width of the port, as from A to a, and its dead points to coincide with those of the crank, the result will be that the valve will be opening and closing during the entire stroke ofthe engine which will, ineffect, admit steam during the whole stroke; and will also be at the opening pointon the other side when the crank is at the other dead point as may be seenby'the small circle at a which is the orbit of the eccentric.

The radius A a I call the radius'of minimum eccentricity. Now if the eccentricity be increased by moving the eccentricalong thejtangent a, b,"projected in the direction of the revolution, toward 5 to any point ,a a a &c.it is obvious that the: valve will still be at the opening point whenfthe crank is at the dead point, although its movement will be correspondingly increased. This increased movementof the valve will causeits port to pass oventhe port of the seat in a shorter time than the whole stroke of the piston varying according to the eccentricity and movement of the valve as may be seen bythearcs drawn withthe several radii of eccentricity A a, A a, A a; and thus admit the steam for a longer or shorter time during each stroke of the engine.

DiagramfiFig. 8, represents the application of the isochronal eccentric to puppet val'ves which are worked by lifters.

Arepresents thecenter of themain shaft and B and C the dead points of the crank asbefore. m n A D D are the toes ofthe lifters, E, E, are the toes of the rocker; and F, F, are the po-sitions of the rocker arm at each opening point. v

A a is the radius of minimum eccentricity andthe diameter of thc'orbitis such as to carry the rocker from one opening point to the other, and with this amount of eccentricity no steam would be admitted into the engine. If then the eccentricity is increased by moving the eccentric along the tangent a I); projected from the radius in a direction opposite to the revolution; to any point a a a &c. the steam will be admitted for a time corresponding to the degree of eccentricity as is shown by the arcs and radii drawn from the center as in the other case. Thus it will be seen that when the eccentric is used in combination with a gridiron slide valve as in the first case; the the greater the eccentricity, the less steam will be admitted; but with a puppet valve as in the other case or with a slide valve when the steam is admitted at the end, the reverse obtains.

In order to regulate the velocity of the engine by means of my improved eccentric, which is the second part of my invention, it is necessary, first, to construct the eccentric with such mechanical arrangements as thatthe eccentricity may be varied while the engine is in motion and, second, that this variation shall be under the control of a governor or regulator so as to be adjusted automatically. The manner in which this may be done is shown in the other figures of the drawing, which represent the manner in. which my invention is applied to a horizontal engine.

A represents the main shaft of the engine, B, the crank, C, the cylinder, D, the bed or frame, E, the chest of the shifting valve, F, the expansion valve chest and G the expansion valve made with five narrow ports corresponding with similar ports in the seat behind it.

H is the shifting valve eccentric, and I is the isochronal eccentric for working the expansion valve G. The particular structure of the eccentric may be more clearly seen in Figs. 4c, 5 and 6 which are drawn to a larger scale.

J is a circular flange with a hub fixed upon the main shaft to which the eccentric I is attached and upon which it slides. It is made with two slots or mortises J, J into which are fitted two lugs upon the eccentric to the ends of which the caps e are bolted which confine the eccentric firmly to the flange and permit it to move transversely to the shaft in the direction of the slots which are at a right angle to the radius of minimum eccentricity as before explained. Upon the outer surface of the hub of the flange J is made two grooves d d running I parallel with the shaft and upon opposite sides of the same, and upon the inside of the eccentric and its lugs are two corresponding grooves 0 a cut diagonally as shown by the dotted lines in Figs. 5 and 6. Within these grooves the slide blocks K K work, the straight bodies'of which fit in the grooves cl and from the inner end of each a diagonal block projects laterally which fits in the diagonal groove 0, so that drawing the slides K lengthwise, will give corresponding lateral movement to the eccentric in a perfectly obvious manner.

The blocks K are attached at their outer ends to the sleeve L which fits loosely upon the main shaft and revolves with it and within the long collar M which is embraced by collars at each end of it. The outside of the collar M is made with a screw which works in the nut N which is attached to the regulator post P as is shown. Upon the collar M is fixed a pulley M by which it receives a rotary movement by a belt from the pulley O on the shaft 0 which is driven in either direction by the regulator R in the manner shown.

The regulator receives its motion from the pulley Q, on the main shaft by means of the belt Q and gear shaft S and bevel gearing as is shown. The construction of the regulator is similar to that usually employed in regulating the gates of water mills, the function of the regulator being to throw the clutch T into one of the bevel wheels V and V, so as to turn the shaft 0 in either direction, as the engine goes too fast or too slow, and through the mechanical arrangement before described, to throw the eccentric 5 I laterally upon the flange J, which by this 9 varying its eccentricity and the point of cut-ting off the steam regulates the velocity of the engine.

The connection between the shaft 0 and the sleeve M is made by a belt so that when the sleeve has arrived at the limit of its longitudinal mot-ion the belt will slip and allow the shaft 0 to revolve without breaking the gearing. Some provision for this purpose is necessary.

The several parts of my invention may be much modified in form and still, embrace the principles thereof and a part of the invention. may be used with advantage without using the whole. As for instance the isochronal eccentric may be used without the regulator and made variable by hand, as would be the casein marine and locomotive engines, and the manner of constructing the details may also be much modified. The eccentric may also be modified as regards the principle of isochronism and may be made to vary the. time of opening or closing as the movement of the valve increases by making the line of variation (a, 6, Figs. 7 and 8) a curve starting from the same dead point (1!, instead of the right line tangent shown. The eccentric may also be used in other machinery thlan steam engines when its peculiar properties would be required. And also of the second part of my invention, any form of regulator may be used in combination with the eccentric, and placed in any convenient position about the engine, and connected therewith by a great variety of mechanical arrangements but I have shown one method of applying the same to a horizontal engine which shows the principle of the combination.

The essence of the first part of my invention consists in making the eccentric With a minimum eccentricity adapted to the valves or other devices to be moved by it, and then makingthe line of variation of eccentricity a tangent to the radius of said minimum eccentricity substantially as described. And of the second part of my invention the substanceiconsists in so combining a governor or regulator With the eccentric that the gov-' erno'r shall control'the eccentricity thereof and thereby vary the point of cut ofi' and thus regulate the velocity of the engine.

What I claim is-.

as described, as a device to be used in machines, for moving steam valves; or for other similar purposes. J

2. I claim the combination of the isochronal eccentric with a governor or regulator in such a manner that the governor or regulator shall control the amount of its eccentricity; and thus, by the variable movement of the valves, regulate the velocity of the engine, substantially as described.

Boston, April 22, 1854:.

WM. 0. HIBBARD.