US379400A

US379400A - Valve-gear

Info

Publication number: US379400A
Authority: US
Publication date: 1888-03-13
Anticipated expiration: 1905-03-13

Description

3 Sheets-Sheet, 1. K. KNOTT.

VALVE GEAR (No Model.)

Patetfited Mar. 13, 1888 new (No Model.) 3 Sheets-Sheet 2.

K.KNOTT.

, VALVE GEAR.

No. 379,400. Patented Mar. 13. 1888.

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3 SheetsSheet 3. K. KNOTT.

VALVE GEAR (No Model.)

Patented Mar. 13, 1888.

NITED STATES PATENT Fricn- KENNARD KNOTT, OF CHICAGO, ILLINOIS.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 379,400, dated March 13, 1888.

Application filed May 28, 1887. Serial No. 239,602. (No model.)

To all whom it may concern:

Be it known that I, KENNARD KNOTT, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Steam-Engines, of which the following is a description, reference being had to the accoinpanyingdrawings, forming a part of this specification, in which- Figure 1 is a plan view of a part of asteamengine having my improvements applied thereto, the cylinder and steam-chest being shown in section. Fig. 2 is a plan view in detail showing the steam-chest in section, with a different valve and reversing mechanism, while the eccentric is represented in a changed position. Fig. 3 is a side view of the valveeccentric and the reversing device applied thereto. Fig. 4 is a like view showing the same in a reversed position; Fig. 5 is a sectional view of said eccentric, taken upon the line a, Fig. 4. Fig. 6 is a side view of the cocentric, showing the same in the act of being reversed. Fig. 7 is alike side view representing the collar as being partly broken away to show the means provided to allow the reversing-aim to pass the stud upon the valve-rod and to cause its engagement therewith upon a reversal of the engine, and Fig. 8 is a side view in detail of the collar attached to the engine-shaft to aid in reversing the eccentric.

Like letters of reference indicate like parts in the different figures.

One object of my invention is to provide a suitable reversing mechanism for reversing the action of steamengines, whereby the usual link-motion may be dispensed with, and a single eccentric may be employed to actuate the valve.

A further object is to provide a movable valve-eccentric applicable to reversing engines and means for automatically adjusting the same upon the reversal of the engine, so that the valve may occupy the proper relation in lead of the piston, whether the engine be run in one direction or another, all of which I accomplish substantially in the manner hereinafter more particularly described, and delinitely pointed out in the claims.

In the drawings, A, Fig. 1, represents the I usual cylinder of a steam-engine. B is the piston; B, the piston-rod; B, the crank-rod, and B the crank upon the shaft Bfl journaled in the usual bearings. 0, Figs. 1 and 2, is the steam-chest. In said figures respectively I have shown different ways of reversing the action of the engine. I will first describe that shown in Fig. 1. Both are equally applicable to my improved eccentric.

Within the steam-chest I secure by means of bolts 0 c, or in any well-known way. a casting provided with double stean'i-ports communicating through the ways D D with the usual steamways, E E, at the respective ends of the cylinder, and an exhaust-way, E" G. Located near the beginning of the ways D D are two-way cocks, F F, provided with arms F F, each of which is provided with studs or pinsff, arranged to engage with slots f upon a plate, F which is rigidly attached to a rod, F, extending outwardly through the wall of the steamchest, whereby said cocks, respectively, may be turned one-quarter of a revolution and in opposite directions.

G is a chamber or steamway communicating at one end with the steamway D and at the other with the two-way cock F, when the latter is properly adjusted therefor; and G is a chamber or way separated from the chamber G and passing beyond the same, as indicated in dotted lines, and communicating, respectively, with the cock F and steamway D.

G" is an exhaust-port separated from the others, as shown, and communicating with the usual exhaust-way, FF.

H is a slide-valve; H, the valve-rod. J is the valve-eccentric, and J the eccentric-rod, which is connected with the-usual shouldenj", attached rigidly to the eccentric-strap. The valves or cocks F F are represented as being so turned as to open the ways D D throughout their entire length, and when the valve H is in the position shown in said Fig. 1 the steam enters the port D,as indicated by the arrow.the exhaust-steam escaping through the port Dand exhaust-port G Upon reversing the cooks F F the steam is directed into the chamber G. through which it is carried to the opposite end of the cylinder A, while the exhaust passes through the chambers or ways G G. An oppo site movement ofthe valve H reverses the conditions, closing the entrance to the port D,when the steam is admitted through the ports D, G, and D and exhausted through the ways D, G, and G As the engine is operated so as to actuate the shaft in agiven direction,itis obvious that the eccentric should occupy such a relation to the shaft as to reciprocate the slide-valve in lead of the piston; but upon reversing the engine it is manifest that the conditions stated would be changed were the eccentric rigid with the shaft, and the valve would be so actuated as to produce a great loss of steam, so much so as to render mostengines of this class of little practical value. Toovercome this objection I cause the eccentric J to be loosely attached to the shaft, but prevented from longitudinal movement thereon. Upon one side of the eccentric,and keyed rigidly to the shaft by means of a key, It, is a collar, K, provided with projecting lugs K K. A Loose pin, J", is passed through the eccentric J and is sccured in place by means of a shoulder, j, and nutj, (better shown in Fig. 5,) by which itis free to revolve in its bearing. Formed upon or rigidly attached to said pin is an eccentric, L, which is loosely fitted between the lugs K K. If preferred, the pin may be rigid and the eccentric L may be attached to a loose sleeve thereon. The valve-eccentric J is preferably formed with a recess, J as shown in Figs. 3, 4:, and 5 therein, for the reception of said eccentric L and lugs K K.

Attached rigidly to the pin J is a pointed arm, M, which is extended from the pin diametrically across the eccentric. L, the normal position of which is such as to cause the arm M to lie in a plane at right angles to the face of the lugs K whether its free end point in one direction or its opposite. Fig. 4 shows said eccentric L in its normal position, which it retains so long as the shaft revolves in the direction indicated by the arrow. Upon a reversal of the shaft the eccentric L is likewise.

reversed, so as to cause the arm M to pointin a reverse direction to that shown in said fig ure, which reversal is accomplished as follows: A pin, J*, is rigidly attached, preferably, to the shoulder J of the eccentricrod, which is so adjusted as to engage with the extreme end of the arm M in whichever direction the shaft B is rotated.

Assuming the shaft to be rotated in one directionas, for example, that indicated in Fig. 7this contact would either bend or break the arm M unless provision were made for one or the other to yield when brought in contact. To overcome this difficulty I preferably place a spring, J upon the collar against which the eccentric L bears, said spring being so adjusted as to normally retain the eccentric L upon a end .of the arm M to touch the pin J. said contact, as theshaft rotates in the direction dead-center, and at the same time to cause the Upon which produces a half-revolution of theeccentric L, leaving it in the position shown in Fig. 4. This action shifts the position ofthe valveeccentric J, which, as stated, is loose upon the shaft, and retains it in such relation to said shaft as to give the proper lead to the valve. The relative positions of the valve-eccentric are indicated by the full and dotted lines in Fig. 3. The eccentric L being normally upon a dead-center in whichever dlrection the engine-sh aft is rotated, it is almost sure to retain the eccentric Jin its proper position. Should it change by accident it is obvious that it could only remain so during a part of a revolution, as the arm M would readjust it upon the next revolution.

In lieu of the spring J the arm M may be made to spring or yield sufficiently to permit it to slip by the pin J. The latter, if preferred, may be placed upon one of the lugsj or other part of the eccentric-strap, or upon a post, S, secured rigidly to the floor, as iuF g. 3, and the arm M adjusted accordingly 1n 1ts relation to the eccentric L. It is obvious that there may be two or more of said pins J in the path traversed by the arm.

In Fig. 2 I have shown a different means for reversing the action of the engine, which consists, briefly, in providing duplicate sets of steam-ports, as N N and O O, communicatlng with the respective ends of the cylinder, exhaust-ports P P, and a sliding plate, Q, having openings arranged to coincide with one or the other of said sets of ports, together with a double valve, H, arranged to operatein conjunction therewith. The sliding of said plate so as to close one and open the other set of ports serves to reverse the engine. I make no claim herein to said construction, as the same is fully described in my application heretofore filed as Serial No. 213,977, September 20, 188 6.

In Fig. 1 the casting in the steam-chest 1 n which is formed the various steamways is shown as applied to an ordinary steam chest and cylinder of the usual pattern, with which it is detachably connected. It would be obvious to one skilled in the art that the same could be somewhat simplified in details of construction if built with the engine.

I do not herein claim the reversing mechanism shown in Fig. 1, except in combination with the adjustable eccentric; but as the same may when properly manipulated be used with good results with a rigid eccentric, I reserve the right herein to make a separate application for a patent therefor.

Having thus described my invention, I claim- 1. Adevice for automatically adjusting the valve -lead in steam engines, consisting of a valveeccentric loosely mounted upon the engine-shaft, a smaller eccentric loosely connected therewith and in turn with a rigid col lar upon the crank-shaft, and provided with an arm extending from its axis and adjusted to engage upon its revolution with a rigid stud, whereby said small eccentric may be revolved and thus shift the valve-eccentric in its relation to the crankshaft upon the reversal of the engine in either direction, substantially as described. 7

2. The combination, in a steam-engine, of a valve-eccentric loosely mounted upon the shaft, a smaller eccentric in operative connection therewith, and with a rigid collar upon the crank-shaft and an arm extending from its axis and adjusted to engage with a stud in the orbit of its revolution, whereby said smaller eccentric may be rotated upon the reversal of the engine and normally retained upon its dead-center in whichever direction the engine is propelled, substantially as described.

3. The combination, in a steam-engine, of a valve'eccentricloosely mounted upon the shaft, a smaller eccentric in operative connection therewith and with a rigid bearing arranged eccentrically to the crank-shaft, an arm extending fro m the axis of said smaller shaft and adjusted to engage with a stud in the orbit of its revolution, and means for permitting said arm to yield during such engagement while the shaft is rotated continuously in one direction and to resume its normal position when said stud is passed, substantially as and for the purposes specified.

4E. The combination, with a steamengine and mechanism for reversing its movement, of the loose valve-eccentric J, rigid collar K, connected with each other by means of the pin J and eccentric L, and means, as the arm M and stud J, for revolving said eccentric L upon the reversal of the engine, substantially as and for the purposes described.

5. An automatic lead-adjusting mechanism for reversible steam-engines, consisting of a valve-eccentric loosely mounted upon the engine-shaft, a secondary eccentric adjusted to rotate between parallel lugs or faces extending laterally from a collar rigidly attached to the shaft and in turn connected by means of a pin with said valve-eccentric. and a finger attached to said smaller eccentric and adjusted to engage with a stud projecting laterally from the eccentric-strap, said finger being arranged in the plane of the greatest eccentricity of said small eccentric, substantially as and for the purposes set forth.

6. The combination, with a steam-engine and means for reversing its action, of the loose valveeccentric J, a collar rigidly mounted upon the shaft and provided with lugs K K, an eccentric, L, loosely fitted between said lugs, pin J connected with said valve-eccentric, stud J", finger M. and means, as the spring J for permitting said arm to yield upon engagement with the stud J* and to thereafter resume its normal position. in which the dead center of the eccentric L is in a plane at right angles to the active faces of said lugs, substantially as and for the purposes specified.

7. The combination, with a steam-engine, of a valve-eccentric loosely mounted upon the engine-shaft, means, substantially as specified, for changing its eccentricity with relation to a given radial line through said shaft, double steainways arranged in the steam chest, a double slide-valve, and the two-way cocks F F, with means for rotating the same in opposite directions, substantially as and for the purposes described.

KENNARD KNOTT.

\Vitnesses:

D. H. FLETCHER, A. O. RAUSH.