US1371424A - Valve-gear - Google Patents

Description

.l. 0. JONES.

VALVE GEAR.

APPLICATION FILED v1.23, 1920.

fly

2 SHEETS-SHEET 1.

Patented Mar. 15, 1921.

Irma/2272; 512 Q Jam;

'lI/II/IIIII NORRIS PETE l5, MC. LITHISL. WASHINGYON. D.

J. 0. JONES.

VALVE GEAR.

APPLICATION FILED JAN.23| 1920.

Patented Mar. 15, 1921.

2 SHEETSSHEET 2.

- sure oi UNITED starts JOHN O. JONES, 0F IlliITGIIELL, SOUTH DAKOTA.

VALVE-GEAR Specification of Letters Patent.

iatented Mar. 15, 1921.

Application filed January 23, 1920. Serial No. 353,408.'

11 '0 all w: fl om it may concern 7 Be it known that 1, JOHN l); JoNns,-a citizen of the United States, residing at lslitchell in the county of Davison and State oi? South Dakota, hi e inventedcertain new and uselul Improvements in Valve-Gears, oi" which the following a specification.

This invention relates to valve gears for engines, and more particularly to valve mech-nisui for locomotives, and especially to that type oi locomotives equipped with either the Baker or Walschaert valve'gear both well known valve mechanisms.

i loplicants invention however may be EilJPliCLi to any type of locomotive designed tor valve gearing to he carried outside the 'l'rau'ies, luit as disclosed in the accompanying drawings the invention may he termed an attachment in that it may he most easily applied to an engine equipped with a Walschaert motion oi the design shown, which latter in extensive use at the present time.

An object of the invention is to provide a valve gear wherein the valve lead varies as the travel oi the valve; or in other words wherein the lead varies as the reverse lever is notched up in the direction of the central notch, both in forward and backward motion.

As the lap is constant with all locomotive valve gears and as the lead is constant in the ll alschaert gear, but one fixed lead is available from the time the en ineer drops the reverse le'rer into the iiull forward notch until he is running under the shortest cut-off of which the engine is capable. To work a high speed lomunotive economically under a pressay two hundred pounds or more with iper-heating equipment it is essential to cut oil at a point somewhere between one quarter and one third stroke, and as it is desirable to have a liberal valve lead when so running so as to exhaust rapidly enough. many locomotives of this type are designed with a constant lead ranging anywhere from three sixteenths to five sixteenths of an imli.-ris long as the engine is rui'; ning at high speed such leads effects economical working and boost the engin ers fuel record. But with the reverse lever in the region of the full forward notch, or in cushion to eii'ect a gentle reverse of the piston, but as a staggering resistance to the latter in the form of a back pressure, thereby rendering the working of the engine heavy or what is sometimes called loggy. Thus in a valve gear with a constant lead the economy effected during high speed is offset by'waste encountered atlow speed. It is the object or" the present invention to provide a "valve gear wherein the travel of the Valve relative only to its lap and lead is derived from the travel of the cross head, but which is provided with means for s0 modifying the motion transmitted to the valve as to result in gradually increasing the lead. as the time of cutoff is reduced. This prevents excessive back pressure since the minimum lead may he made very small (such as athirty second or one sixteenth of an inch) when starting a heavy train, and increase to three eighths of an inch at the minimum cut-off.

A. further object of the inventionis to provide 2 whereby the valve is momentarily delayed in its movement to holdthe port open just after the piston. starts-its stroke.

To this end the invention consists in the construction, combination and arrangement of parts hereinafter described and claimed. in the ru-companying drawings forming part of the specification:

Figure '1 is a side elevation oil a portion of a locomotive equipped with a much used type oi ll 'alschaert valve gear the cylinder and valve chest being shown semi-diagrammatically in cross section, the short dark lines at the top of the figure outlining applicants invention as an attachment.

Fig. 2 is a side elevation of the invention illustrating its application to a locomotive the crank being'on baek'center.

Fig. 3 is a perspective view of the invention.

Figs. t and 5 are diagrams showing the crank on back center andv lower quarter respectively.

Fig. 6 is a perspective view of the link partly broken away, the part broken away being shown immediately to the left thereof.

Fig. 7 is a perspective view of the link end of the radius rod.

Fig. 8 is a perspective view of the upper end of the'lap and lead lever.

Fig. 9 is a perspective view ot the valve rod support.

valve gear equipped with means Fig. 10 is a perspective view of one of the slide blocks of the combination lever, and

Fig. 11 is a diagram illustrating pha of the valve movement.

Referring to Fig. 1 of the drawings, the parts of the alschaert are as to lows: A is the cross head, B the main connecting rod, C the main crank pin, D the eccentric crank, E the eccentric rod, F the link, 7. the radius rod, H the radius rod han'ger, I the lifting arm, J the lifting shaft or rock shaft, K the lifting arm, L the reach rod, M the cross head arm, N the lap and lead lever connector, the lap and lead lever, P the valve stem, Q the valve stem guide. it the radius rod guide and S the link foot.

In addition to these T represents the V valve, U the cylinder, V the piston and its rod and W the cross head guide bars. In the application of the invention of the design shown in the drawings, the parts 3. H, L, I, J, G, Q, 0 and R are removed. Extending from the top of the vertical member X of the frame to the top Z of the steam chest and disposed in the Yeitical pin in which move the valve rod and piston rod and arranged parallel to said rods and located directly above the cross head guide bars and a distance above the level of said steam chest top, is the slide way A. The slide way is formed by housings 1 and 2 suitably secured respectively to the member X and the steam chest, the two housings being joined together by a pair of spaced guide bars 3 one above the other. While the slideway A is shown supported on the steam chest cover Z and the member X, it is to be understood that it may be supported in any sni alfile manner, as, for run 7 a rectly on, what is commonly termed the main frame which carries the boiler, not shown, and is indicated in dotted lines in Figs. 1 and 2, the three drivers being in dicated in fine solid lines. The cylinder with its steam chest, the cross head guides and the member X are all supported on the main frame the mode of connection there with not being shown and form collectively the adjacent supporting structure for the valve rod and the crosshead. Slidably mounted in said slide way is the cam block 5 having a uniformly curved or circular cam slot 6 of uniform width cut through the side thereof, the concavity of the slot being directed downwardly. Directly beneath the slide way A and supported by means o stands 4 o nthe cross head. guide bar and arranged parallel with the valve rod P is the valve rod guide bar 7 which slidably fits the opening 8 of the valve rod support This support is provided with oppositely disposed laterally extending threaded studs 10 disposed perpendicular to the opening 8.. and rotatably fitting the opening 1]. of the slide 12. The latter is formed with a pair of parallel channels 13, one on either side of the opening 11 said channels being longitudinally in a plane perpendicular to the longitudinal axis of said opening. The blocks 12, of which there are two, one for each of the studs 10 whereon they are held by means of the nuts 14;, function as a sliding fulcrum for the lap and lead lever B which may be described as follows. The lever comprises a downwardly extending wide fiat long arm portion 15 and two oppositely disposed spaced upwardly extending short arms i6, one thereof alining with said long arm and the other being offset, the two arms forming a comparatively large bifurcation adapted to movably receive widthwise the valve rod support 9. Cut through the flat sides of the short arms 16 are the oppositely disposed elongated rectangular openings 17 adapted to slidingly receive the portion 18 of the blocks 12 the channels 13 slidingly receiving the long side walls of the openings 17. A pivot 19 is supported in said short arms and spans said bifurcation above the openings 17, and a pivotal connection 20 at the extreme lower end of the long arm 15 connects the latter with the connector link N, which latter is pivotally connected at 22 with the cross head arm M. The pivots 10-19-2-(l and 22 are all axially parallel and disposed horizontally at right angles to the path of travel of the piston. Likewise are the pivot pins 23 to 32 inclusive to be hereinafter specifically described. The pin 24 extends through the cam slot 6 of the cam block and pivotally supports, one on either side of the latter, a comparatively short down wardly extending connector lever 33 or floating lever, the lower end thereof being pivotally mounted on the pin 19 within the bifurcation of the lap and lead lever 13. Fixed one on either end of the pin 24 and extend-- ing horizontally to the stand 2 on the steam chest are the steady links 34, the opposite respective ends thereof being fixed on opposite ends of the pin 25 which latter is rotatably supported in said stand 2 as best shown in Fig. 2 the steady links are disposed horizontally when the lever 33 is positioned radial or perpendicular to the curvature of the cam slot, the curvature of the latter being sv ninetrical about a \ertical l ne lilSBCJ ing the cam slot midway between its ends. Thus the lever 33 will move bodily down- Jvr rll the same degree on either r' e of s id his ,ctinfr line when the cam blocs. is s Pivotally connected by means of the pin 26 to the cam block is the rearwardly extending tie rod 35, having pivotal connection 31 with the comparatively short vertical arm 36 fixed on the rock shaft 37 the latter being supported. horizontally on the engine frame and at right angles to the line of travel. The crank arm 38 is also fixed on the rockshaft and has pivotal connection 32 with the reach rod 39 leading io'the cab, from whence the engineer actuates the rockshaft. Fixed on the outer end of the rockshait is the lifting arm 40 having pivotal connection 29 with the lifting link 41, the latter having pivotal connection 28 with the radius rod 42. The radius rod is formed (Fig. 7 with a deep bifurcation 43 having a transverse pivot pin 44 projecting therethrough. The opposite end of the radius rod has pivotal connection 23 with the levers 33, said pivot constituting a fulcrum whereby when the radius rod is moved longitudinally the lever 33. will carry the lead lever B with it and thereby move the valve T. It will be noted that as the levers 33 are swung upon their pivots 24, the lead lever is moved bodily the link N yielding vertically and the blocks 12 sliding in the openings 17 The radius rod has the usual slide block connection with the link C (Fig. 6). The link shown comprises a, circular segment open at its curved edges, its concave edge being directed forwardly. Midway between its ends it is provided on opposite sides with a transversely disposed trunnion pin 27 the latter being journaled respectively in the spaced lugs 45 forming part of the housing 1. The housing 1 extends rearwardly beyond the cross-,

head guides so as to render the radius rod as long as possible, the latter straddling loosely with its bifurcation 43 the central rib 46 oi the link. The rib 46 is formed with a longitudinally centrally disposed slot 47. wherein works slidinglythe block 48 having a bore 49 axially capable of alinement with the trunnions 27, the pin 44 being journaled in said bore. is caused to be rocked about its trunnions and the pivot 44 is coincident with the latter as shown in Fig. 2 of the drawings no motion is transmitted to the lever 33 suspended from the cam block 5, the valve gear operating precisely as does the WValschaert shown in F 1. The ratio however of the distance between the pivots 10 and 19, to the distance between the pivots 10 and 20 is greater than the ratio between the corresponding distances in the VValschaert valve gear because (as stated in the foregoing) the lead in the latter is constant, or, in other words the throw of the short arm of the lap and load lever is designed to equal twice the lap plus twice the lead, and since the lead is limited, to about one quarter inch for reasons explained inthe foregoing, the ratio must be smaller. lVhen positioned as shown in Fig. 2 the throw of the short arm of the lever B is maximum, which may be designed to yield a lead of three eighths of an inch or more as desired, the pin 24 it being noted resting on the highest part of the cam slot 6.

'lieferring to Figs 4 and of the draw- Thus, when the link action of the link and lead lever.

ings, the reach rod 39 is represented dia grammatically as being connected with the reverse lever indicated by thenumeral 50, and working in connection with a notched rack indicated by the numeral 51.

In Fig. 4, the reverse lever is assumed to be in the first notch (the notches not being indicated) the cam block having cammed down bodily the lap and lead lever B whereby the length of the short arm thereof (or that part above the fulcrum has been. reduced an amount indicated at Obvi:

ously the long arm has thereby been proportionally lengthened. Thus,in Figs. 4 and 5 the throw of the short arm is mini mum, Fig. 5 showing the reverse lever as being in the rearmost notch. The minimum throw may be so proportioned as to yield a sixteenth of an inch or less lead which would be ample for cushion purposes, that being the main object of any lead when the reverse lever is ina far forward notch. The lead, therefore, gradually increases from about one sixteenth to maximum as the re verse lever is notched up and the pin 24 thereby simultaneously cammed up in the cam slot. i

In Fig. 4, the crank is, on back center, the port beingopen to the extent of the maxi mum lead alone, but the eccentric being approximately on lower quarter, (its most active link moving position), will rapidly move the valve so as to fully open the port through a fraction of the next quarter. The

movement of the valve at this point is modified so as to momentarily but not abruptly reduce its rate of speed, the port being there by held open for a longer period of time and then rapidly closed by the combined This action is illustrated in Fig. 11 wherein the eccentric is approximately on lower back eighth and the crank on upper back eighth the reverse lever being assumed to be in full forward notch. The modified motion is due to the oppositely disposed :tulcrumcd levers and B, which. (Fig. 11.) when becoming longitudinally alined partially neutralize each vothers valve moving action in that their short arms joined by the pivot 19 are at this time traveling in the same direction (see arrows) thereby rendering the pivot 1.0 almost stationary. So soon however as the crank reaches upper center both the crank and eccentric travel forward to rapidly close the port.

The best results are to be obtained by making the rods or links 34 and the radius rod E as long as possible so as to reduce the arcs described by their respective adjacent outer ends;

While applicants radius rod is somewhat out of alinement with the valve rod the lever 33 forms a strut the pin 24 being approximately in the center of the cam slot (where there can be no slipping) when the engine is going at high speed. As a drop of one half inch of the lever 33 is adequate to effect a satisfactory change of lead, the cam slot may be of large radius so that the slipping or lost motion is almost negligible.

lVhile applicauts valve gear is shown in connection with an. internal-admission valve it is to be understood that the principle underlying applicants invention may be applied in connection with external-admission valves by simply reversing the pivots ll) and 23, that is, connecting the radius rod with the slidable pivot 10 and the valve rod with the pivot. the lead thereby being rendered variable as in the construction shown.

1 claim:

1. In a valve gear for locomotives the ombination with a valve rod, crosshead, main rod, main crank pin, eccentric on said crank pin, the reciprocatory link actuated by said eccentric, and the adjacent structure supporting said valve rod and crosshead, of a lap and lead lever operatively connected with the crosshead and having slidable pivital connection with the valve rod so as to reciprocate the latter when actuated, an upwardly extending lever arm pivotally connected to said lap and lead lever at a position above said slidable pivotal connection, vertical yieldable pivotal link connections pivotally connected with the top of said lever arm extending approximately horizontally away from the latter to a position on said structure to be pivotally mounted thereat whereby to hold the top of said lever arm so as to render the latter movable bodily vertically and swingable laterally, a radius rod pivotally connected to said lever arm at a position between the lap and lead lever connection and the yieldable connections of the latter, said radius rod havin slidable pivotal connection with said reciprocatory link so as to be reciprocated thereby when actuated, and hand operable controlling mechanism supported on said adjacent structure operatively connected with said lever arm and said radius rod for bodily moving both, said controlling mechanism including a slidable cam block engaging said lever arm to bodily raise and lower the latter for the purpose set forth.

2. In a valve gear for locomotives the combination with the reverse lever, the valve rod, crosshead. main rod, main crank pin, eccentric on said crank pin, the reciprora tory link actuated by said eccentric, and the adjacent structure supporting all of said parts, of a fulcrumed lap and lead lever being movable relative to its fulcrum and operatively connected below its fulcrum with the crosshead, said fulcrum being fixed on the valve rod, mechanism operatively connected with the reverse lever for moving at will. said lap and lead lever relative to its fulcrum. said mechanism including a cam block adapted to be slid when said mechanism is actuated, a swingable depending lever arm depending from and in engage meat with said cam block to be raised and lowered therel y when the latter is actuated. and pivotally connected to said lap and lead lever at a position above its fulcrum, and a radius rod pivoted at its respective opposite ends to id lever arm and said link so as to be recun'ocatml by the latter when the latter is actuated. and means for actuating said radius arm. said radius arm being so connected with said lever arm as to bring the latter into longitudinal aliuenient for a period of time with the lap and lead lever during: the valve moving action of the latter for the purpose set forth.

2 valve gear for locomotives comprising a lap and load lever having pivotal link connection at its lower end with the crosshead to move therewith a swingable lever arm pivotally connected at its lower end with said lap and lead lever, vertically yieldable link connections for said lever arm extending to the adjacent structure of the locomotive and pivoted thereon so as to render said arm movable bodily vertically and swingable laterally, an oscillatory curved. link, a radius rod slidahly pivoted thereon to be reciprocated thereby when actuated and pivotally connected at its for ward end to said lever arm at a position intermediate the ends thereof, means for moving: said radius rod on said link to move the atter when oscillated, pivot means fixed on the valve rod. guiding means therefor, and slidable pivot means on the lap and lead lever near the upper end thereof to cooperate with said pivot means to reciprocate the valve rod when the lap and lead lever is moved, and lever mechanism including a cam operatively connected with said radius rod moving means and operating concurrently therewith for simultaneously moving said lever arm bodily and causing it to be swan thereby to modify the move ment of the lap and lead lever for the purpose set forth.

l. In a locomotive valve gear of the lValschaert type the combination with the frame, the crosshead arm, the link, the radius rod therefor, and the shifting mechanism for the latter, of lap and lea d lever extending upwardly beyond the valve rod and. having a vertically yieldable connection at its lower end with the crosshead arm. mechanism connected with said. shiftingmechanism and including a swingable and vertically movable lever arm pivotally connected intermediate its ends with the radius rod and at its lower end with the top of said lap and lead lever for moving the latter bodily vertically at will, said mechanism including a horizontally slidable cam, en

gaging said swingi able lever arm to raise and lower the latter when said mechanism is actuated, pivot devices for the lap and lead lever slidable on the frame and moving with the piston, and upwardly slidable means on the lap and lead lever to rotatably engage said pivot devices whereby the latter may be free to be moved by the combined horizontal and vertical action of said lever arm when said shifting mechanism is actuated;

5.11; a locomotive valve gear of the l'Valschaert type, a slldable plvotal 11lcrum connection connecting the combination lever with the valve rod, a depending swing- 'pivotally connected With the latter above said slidable'connection, said lever arm being pivotally connected With the radius rod intermediate its ends so as to be swung thereby, whereby its pivotal connection With the combination lever is moved relative to said fulcrum connection to change the valve moving action of said lap and lead lever when the locomotive is moving, and means for simultaneously moving at will said depending" lever arm and the radius rod for the purpose set forth.

In testimony whereof I aiiix my signature in presence of two Witnesses.

JOHN O. JONES.

Witnesses GEORGE VoELKER, IRENE WILLIAMS.

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