US1076406A - Steam-engine valve-gear. - Google Patents

Description

W. S. BROWN.

STEAM ENGINE VALVE GEAR.

APPLIGATION FILED MAB.24, 191s.

Iz sums-SHEET 1,

Patented Oct. 21, 1913.

W. S. BROWN. STEAM ENGINE VALVE GEAR.

APPLICATION FILED MAR.24, 1913.

3?@767406 Patented 0ct.21,1913.

2 SHEETS-SHEET 2.

@df @AW y 1; Fig. 3 is a section on the 'guide yoke extension, 15.

iciirrn raras recenser cierren.

l VJILLIAM SHERMAN BROWN, OF KNOXVILLE, TENNESSEE.

4STIE.All/LElilGINE VALVE-GEAR.

Specification of Letters Patent.

Patented (tot. 21, 119113.

Application filed March 24, 1913. l Serial 11o. 7'5(i,500.-

To all whom/15 may concern:

Be it known that l, WILLIAM SHERMAN BROWN, a citizen of the v,United States,.residing at Knoxville, in the county of Knox and State of Tennessee, have invented a new and useful improvement' in Steam-Engine Valve- This improvement is applicable to' t-he mechanism described by my United States- Patent No. 1,033,532, granted July 23, 1912, for steam-engine valve-gear.

1n the accompanying drawings, Figure 1 is a side elevation, portions being broken away, showing my improvement applied to one side of a locomotive; Fig. 2 is a plan of a portion of the mechanism shown by Fig. line, 3,3, of Fig. 2, looking toward the right; Fig. 4 is a section on the line, 4 4-, of Fig. 2, looking in the direction of the arrow, Fig. 5 is a plan of the bridge upon which the segmentis seatcd; Fig. G is a side elevation of said bridge. y

Referring to said drawings, 1 is the cylinder, 2 is the valve chest, 3 is the slide valve located within said chest, and /l is the usual valve `stein extending tlirougli said chest. The ordinary piston, 5, located within said cylinder, and has applied to it tl e ordinary piston rod, 6. 'which is joined lo the ordinary cross-head, .7, confined between the usual horizontal', parallel 'guideoai-s, cl supported at their rear ends by the 4 To said crosshead is coupled one end oitlieA usual con.- necting rod 'or piti'nan, 9, the other end of said rod being coupled to the usual inain crank, 10, carried by a drive wheel,`D, On the main crank, 10, is rigidly mount-ed an auxiliary crank, 12, standing 90 degrees forward of the main crank. To said auxiliary crank is coupledone end of the auxiliary pitman rod, 13. A bridge, B, is located above the frame, A, and extends from the ordinary guide-yoke, 14, and guide-yoke extension, 15, to the cross beam or plate, 16, and is secured to said nido-yoke and to said cross-beam by ineanso bolts, 17. Said'bridge is iii the `I'form of a plate having its length horizontal'and being turned to bring its long edges into an uprighty plane. At its rear end, the bridge has a lateral extension, 18, resting against the cross-beam, 16,

vand receiving said bolts, 17. At its forward end the bridge has a transverse extension,

1.9, reaching to both sides of the body of the bridge and yresting against the guide yoi'e, 14, and the guide yoke extension, 15, and rrceiving said bolts, 17. rllhe innermost oi said bolts extends through the transverse extension, 19, and the guide yoke, 14, while the others of said'bolts extend through the transverse extension, 19, and through the guide yoke, 14, and the guide yoke extension,

15. On the forward portion of the transverse extension, 19, vand integral. therewith is an ear, 20, which is directed rearward; and on the inner portion of said transverse extension is ano-ther ear, 21, also directed rearward and located horizontally opposite the ear, 20. Each of said has a bearing, 22, receiving the ends of a shaft, 23. (1n said shaft is a. bell crank or rocking member, C, preferably rotatable on said shaft, the latter being held ininiovably in its bearings. Said bell c 'ank lhas two approximately horizontal arms, 2-1, and a depending arm, 25. The latter ai'in is coupled to the valve-stein, 4. By rocking the bell crank, the valve stein is reciprocated. y

An approximately upright link, 26, has its upper end coupled to the. arms, 24e, of the bell crank, while its lower end is coupled to the forward end of the auxiliary pitmaii rod, 13, both ends of said link being forked to receive said rod and said arms, as shown in the drawings. Said arms, 24, are also forked to receive the upper ends of the link, 2G.

0n the upper edge of the bridge, B, are horizontal bosses, 27. A segment or link, ll, has at each end a foot,.2d, resting upon one ofl t-lie bosses, 27'; and bolts, '29, extend through said feet and said bosses for securing said segment rigidly upon the bridge, B.

Said segment is in the form of a plate having its body set in an upright' plane.

1n the segment is a curved slot, 30, in

all

which rests a slide block, 3l, to which is coupled the upper end of an approximately up-A right link, 32. The lower end of said link is coupled to the auxiliary pitman rod, 13, `The slot, 30, is preferablyf' said bolt to become coincident' with the axis' to which said slot is concentric.` in ap proxiinately horizontal link, 34, is coupled by its forward end tothe slide block, 31, and by its rear end to the arm, 35, which is rigid on a rock shaft, 36, supported in bearings, 37. On said rock-shaft is an arm, 38, to which is coupled a rod, 39, which is in turn coupled to the ordinary reversing lever, 40, working on a sector or quadrant, 41.

ln operation, the slide block, 3l, is set in any desired position in the slot, 30, by means ofthe reversing lever, and while said block is so set, the link, 32, oscillates on said block with each reeiprocation of the auxiliary pitman rod, the axis of the bolt, 33, moving in an arc in which lies the axis to which the slot, 30, is concentric; and the distance between the wrist of the auxiliary crank, 12, and the bolt, 33, is suchas to bring the axis of said bolt into the slot axis when the drive wheel is on either the frontl or the rear quarter. ln Fig, 1, it is shown on the front quarter, the auxiliary crank being on the top. During each such reciprocation, said auxiliary pitmanrod rocks bodily with the axis of the bolt, 33, as a fulcrum. |This involves the rising and falling of the forward end of said auxiliary rod, and during such movement of said end of said rod, the link, 26, is forced up and down and such movement of said link causes the rocking of the bell crank, C, and the reciprocation of 'the valve stem, fl.

rhe gear is reversed by throwing the reversing lever across the center in the usual manner, and the opening of the valve is varied by moving, the slide block nearer to or farther from the middle of the slot, 30, this being accomplished by' the aid of suitable'notches (not shown) on the reversing lever sector. When the slide block is on the middle of said'slot, the valve motion ifi' re# duced to the extent of the lead 7.

The drawings have been copied from larger.` working drawings used in applying my improvementJ to a railway freight locomotive having a piston stroke of 30 inches and having a maximum valve travel. of 5% inches and a lead of three sixteenths of aninch. The radius of the auxiliary crank, 12,

(measuring from the driver axis) is 8 and inches. The distance from th crank along the auxiliary pitman the axis of the bolt, 33, is 74 and auxiliary rod, 13, to inches.

nordsee lfronil the latter point on said pilxnan rod to the link, 2G, is l0 and inches. The length of the link, 32, is 35 and inches, and that, `as already described, is also the radius of the curved slot, 30, in the segment, E; and the center of said curved slot coincides with the axis of the bolt, 33, when the auxiliary crank is ou the upper quarteror the lower lquarter, at which time said bolt is one and live sixteenth inches below the level of the driver axis and the cylinder axis (the working line 7 or center line of motion The length of the link, 2G, is 32 inches. |lhe height of the axis orfulcrum of the bell crank orrocking member, C, above the level of the center line of motion is 32 and inches. The length of the arms, 24 and 25, of the bell crank is 12 and Jg incheswll'he rocking member, C, is not a true bell crank, its angle being less than ninety degrees-72 degrees,

`W hen the engine is in forward'motion and the main crank is on the back center and the auxiliary crank on, the upper quarter, the arm, 24, is 2 and degrees back of a vertical line cutting the fulcrum, and the arms, 2 4, are 15 and degrees below` a horizontal line slitting the fulcruni. lVhe-n (he slide block, 3l, is set for full valve travel (5 and inches), the forward travel of the arm, 25, from the position mentioned is 7 and Tg degrees and the back travel of said arm from said position is 19 degrees, and the arms, 2li,

travel downward and upward correspondingly. Thus the larger portion of the travel of the rocking member arms is within the .90 degree angle formed by `said vertical and said horizontal lines. These relative proportions and positions of the various parts of the mechanism produce the desired quick movement of the valve during the opening and closing and also produce equalized travel of the valve over the port during the forward motion and during the backward motion. Fig. 1 of the drawings shows the slide block on the center, while the port is shown open full. This is done because the very small actual portopening, wheny the slide block is so set, can not be shown;

lt is to be observed that my improvement eliminates from the valve mechanism'the ec centric and also all parts having a high velocity. No part of the valve mechanism is connected to the connecting rod nor the cross-head. Movement is transmitted to the valve stein from the wrist` of the auxiliary crank and said wrist travels in a relatively A small circle. Thus the movementof the auxiliary rod and the links, 26, and'32, are

.through relatively short ranges. Furthermore, it is to be noted that lost motion due to wear at the wrist of the auxiliary crank will chiefly modify the lengthwise movement of' the auxiliary pitman, 13, while the llO/ movement transmitted through the link, 26, is approximately at right angles to said auxiliary pitman. Hence the modification of vthe longitudinal movement of said pi'tman is substantially not transmit-ted to said link. And it will be seen that such modification of the rocking movement of lthe auxiliary pitman dueto wear at the wrist of the auxiliary crank will att'ect the link, 26, in minimized form, because the portion ofthe auxiliary pitman between the axis, 33, and the link, 26, is much less than between said axis and the wrist of the auxiliary crank. In this connection it is to be remembered that wear by the auxiliary crank wrist in the auxiliary pitman is chiefly in the direct-ion of the length of said pitnian. Such wear produces what is termed lost motion or pounding at the crank.

l claim as my invention:

1. ln a steam engine valve gear, the conibination of an adjustable', horizontal segment, a slide block on said segment, means for moving saidv block, an auxiliary crank,

an auxiliary rod coupled to said crank, and two approximately upright links, each having its lower end coupled to thev auxiliary rod and one having its upper end coupled to said slide block and the other having its upper end in operative relation with the distributing valve, substantially as described.

2. .In a steam engine valve gear, the combination of an adjustable, horizontal ment, a slide block on said segment, means for moving said block, a bell crank in operative relation with the distributing valve,

'an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower end coupled to the auxiliar-y rod and one having its upper end coupled to said slide block and the other having its upper end coupled to said belll crank, substantially as described.

3. In a steam engine valve gear, the oombination of an approximately horizontal bridge, a horizontal segment adjustable on said bridge, a slide block on said segment, means for moving said block, anauxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links, each having its lower end coupled to the auxiliary i'od and one having its upper end coupled to said slide block and the other having its upper end inoperative relation with the distributing valve, substantially as described.

Ll. ln a steam engine valve gear, the conibination of an approximately 'horizontal bridge, a horizontal segment adjustable on said bridge, a slide block on said segment, means for moving said slide block, a bell crank in operative relation with the distributing valve, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower end coupled to the auxiliary rod and one having its upper end coupled to the slide block, and the other having its upper end coupled to the bell crank, substantially as described. i

5. In a steam engine valve gear, the combination of a bracket-,a bell crank hinged to said bracket and being in operative relation with the distributing valve, a slide block, adjustable means for supporting said slide block, means for moving said slide block, an auxiliary crank, an auxiliary rod, and two approximately upright links each having its lower end coupled to said auxiliary rod and one having its upper end coupled to said slide block and the other having itsupper end coupled to said bell crank, substantially as described.

6. In. a steam engine valve gear, the combination of two stationary members rigid on the frame, a bridge having its rear end secured to one of said stationary members and having its forward end secured to the other of said stationary members, a bell `crank supported by said bridge and being in having its upper end coupled to said bellv crank, substantially described.

7. In a steam engine valve gear, the combination ol' an approximately horizontal bridge having bearings integral therewith, a segment adjustable on said bridge, a slide block on said segment, mains tor moving said slide block, a bell crank in operative relation with the distributing valve and-supported by said bearings, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower end coupled to the auxiliary iod and one having its upper end coupled to the slide block and the other having its upper end coupled to the bell crank, substantially as described.

8. 'In a steam engine valve gear, the combination. of an approximately horizontal bridge having a transverse extension and bearings integral therewith, a segment adjustable on said bridge, a slide block on said segment, means for moving said slide block, a bell crank in operative relation with the distributing' valve and supported `by said bearings, an auxiliary crank, an auxiliary rod coupled to said crank, and two approximately upright links each having its lower *end coupled to the auxiliary rod and one dayh March, in the your one thousahd nine havmg lts upper end coupled to the shde hundred and thirteen.

'block and the other having its. upper end f 4 y ,T T y coupled to the bell crank, substantially as n ILLIAM SHERMAN BRO 1" 5 described. W'tnesses:

ln testimony whereof l have signed 1:5132# ED REICH, name7 in presence of two Witnesses, this l'h' H. P. STRAYBR.

@spies of mepaemvmay be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. G.

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