US521706A - High-speed engine - Google Patents

Description

(No Model.) 5 Sheets-Sheet J. DOW.

HIGH SPEED ENGINE.

N0.-5Z1,706. s Patented June 19, 1894.

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J. Dow. HIGH. SPEED ENGINE.

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5 Sheets-Sheet 4. J. DOW. HIGH SPEED ENGINE.

Patented m1116119, 1894.

(No Model.) 5 Sheets-Sheet 5. J. DOW. HIGH SPEED ENGINE.

Patented June 19, 1894. Y

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UNITED STATES PATENT OFFICE.

Y l JOSIAH DOW, OF PHILADELPHIA, PENNSYLVANIA.

HIGH-SPEED ENGINE.

iPEClFICATION forming part f Letters Patent No. 521,706, dated June 19, 1894.

Application filed vDecember 14, 1893. Serial No. 493,620. (No model.) y l Be it known thatI, JOSIAH DOW,a citizen of theAUnited States/residing at Philadelphia,"

' in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in'High-Speed Engines, of

' whichA the following is a specification'.

My invention relates to high speed vertical compound steam engines and consists in several novel features in the construction, ar

rangement and combinations of parts and devices as hereinafter described and more parthe exhaust of the high pressure cylinderV to the low pressure cylinder, whereby the clearance between the cylinders and through their valves may be made far less than has been heretofore practicable in engines of this class.

Another object of the invention is to control the admission of steam to the low pressure cylinder by means of the valve of the high pressure cylinderwhich preferably combines both inlet to and outlet from the said high pressure cylinder, the opening of the exhaust from the high pressure cylinder becoming the steam opening for the low pressure cylinder and determining the lead of steam vide an improved and reliable governor-confr thereto. s Y

Another object of my invention isl to provide mechanism for working both sets of valves, the high pressure and thelow pressure, from one wrist plate.

Another object of the invention is to protrolled mechanism for` actuating the cut oft plates to determine the point of cut ott and equalize the motion of the valves at both ends 'of the high pressure cylinder.

Another object of the' invention is to `so arrange the main rocker arm and its connection with the engine shaft as to correct the" angular advance of` the rocker arm eccentric and rod with relation to each otherand cause the high pressure andlow pressure valves to have thefsame movements in both the up and down strokes. Y

Another object of the invention is to provide throughout the engine a perfect bal-r ance as by part against part where most convenient, or otherwise by counter-balancing at suitable points, so that everything will be balanced from the pistons, rods and cranks to the valve gear, and its actuating mechanism, the governor-controlled cut ed devices and every detail of parts concerned in the distribution of steam and the working of the engine.l f

In the annexed'drawings illustrating the inventio'n Figure 1, shows, in dotted lines,

yan elevation of the frame and cylinders of a erating the valves of the high pressure and low pressure cylinders from the engine shaft and controlling the point of cut off by the action of a governor driven from said shaft. Fig. 2, is a similar elevation at a right angle to the view shown in thev preceding ligure. Fig. 3, is an enlarged vertical section, on the line 3 3, Fig. 4, through the high pressure and low pressure cylinders, initial steam chamber,exhaust chamber, closed intervening spaces, valvesrand steam passages, with the pistons and piston rods in elevation. Fig. 4, is a horizontal section on. the line 4 4 of Fig. 3. Fig. 5, is a section onk the line 5 5 of Fig. 3, with the pistons removed. Fig.

6, is a vertical transverse section on the line 6 6 of Fig. 5, through the steam inlet and initial steam chamber. Fig. 7, is a view of one of the valves of the high pressure cylinder. Fig. 8, is a view of one of the valves of the low pressure cylinder. Fig. 9, is an enlarged perspective of the governor controlled mechanism for equalizing the actionof the high pressure valves and determining the point of cut 0E. Figs. 10 and 1l, are partly sectional detail views ot' parts of said governor controlled cut off mechanism.

Referring, first, to Figs. l, 2, 3, 4t, 5 `and 6, the numeral l, designates the high pressure cylinder and 2 the low pressure cylinder. Theset cylinders, as shown, are placed vertically and in such relation to each other that a simple steam passage 3, only the width of the cylinder ports, serves to conduct the whole ofthe steam from the exhaust of the high pressure cylinder to the induction of the low pressure cylinder, the admission of steam to the low pressure cylinder being controlled by the exhaust valve of the high pressure cylinder. The engine may,however, be preferably built with each valve at the high pressure cylinder combining both inlet to and outlet from that cylinder. It will beobserved that the cylinders are placed close together and may be constructed practically integral and in compact close relation to each other with the steam passages 3, `at top and bottom, formed in the casting and extended from the valves of the high pressure cylinder to the valves of the low pressure cylinder. The valves of the two cylinders are thus connected by simple and direct passages without any intermediate chambers or intermediate receiveror pipe.

Next to the high pressurecylinder l, is the initial steam chamber 4; then a closed air space 5, either filled with non-conducting `material or not g then the `exhaust chamber G from the low pressure cylinder 2 and then, between the exhaust chamber and the low pressure cylinder, another air space 7 that may, or may not, be filled with non-conducting material. As shown in Figs. 3,4and 5 the cylinders 1 and 2 may be partly or Wholly surrounded bya jacket 8, filled with `magnesia, asbestus or other non-conducting substance.

rlhe initial steam chamber 4 is provided on :one side with a steam inlet 9 to which asuitable livalved steam inlet pipe 10 will be connected, as indicated in Figs. 1 and 2.

cylindrical valve seats 4 each of which communicates on one hand through a port or ports 11 with-one end of the high pressure `cylinder and on the other hand with the passage 3 leading to the corresponding valve of the `low pressure cylinder. Each port ll is controlled by `a cylindrical oscillatory balanced valve 12 constructed in the manner devscribed and claimed in Letters Patent No. 498,635, granted to me May 30, 1893. This valve 12 is hollowr and has steam admitted into the interior only through annular series `of peripheral openings or ports 13 at its two ends, as shown in Figs. 4 and 7. Surrounding the ends of these valves 12 are steam chambers 14 communicating with the initial steam chamber 4 through passages 15, Fig. 6. When the valves 12 are in place the steam chambers 14 have a steam tight separation from the valve `seats 4 by means of packing rings 16, Fig. 4, resting closely around the valves and in the innersides of said chambers. Each hollow oscillatory valve 12 at the high pressure cylinder is provided on one side, between its peripheral end ports 13, with a narrow port, or ports 17, Figs. 3 and 7 to permit steam to pass through the interior of the valve into the high pressure cylinder lwhen the valve port 17 is broughtinto coincidence with the cylinder port 11, hereinbefore mentioned. In the opposite side of each valve 12 is a packed balance port 18, Fig. 3, and between is the ports 17 and 18is an exterior cut away or depressed portion or pocket y19 to form an exhaust port or passage so that when the valve is moved into proper position to present one side of said pocket or port 19 to the cylinder port 11 and the other side to the passage 3, between the cylinders, a direct channel is afforded through which ,the exhaust steam from. the high pressure cylinder passes tothe valve ofthe low pressure cylinder.

The construction and operation ot' the cylindrical oscillatory valve 12 are substantiall y the same as the valve described in my above named prior-patent. It will be observed that steam is `not allowed to pass around the valve and that no steam actually passes out of the valve through the balance port. The outside of the valve being thus isolated from the pressure of steam, the excess of pressure at the balance port 18 over that at the port 17, through which steam passes to the cylinder, is only sufficient to holdthe valveclosely upon its seat at both steam randexhaust passages and thus render the val-ve .as nearly perfectly balanced as may be consistent with arm scat.

The opposite ends of the low pressure cylinder 2 are provided with ports 2O that communicate with cylindrical valve seats 6 in each of which is placed a solid cylindrical two-way valve 21 having its exterior cutaway longitudinally on one side to form a port or passage 22, Figs. 3,4 and 8, similar' to the old Corliss exhaust valve. The cylindrical valve seats G communicate with the connecting passages 3 between the two cylinders and also by exhaust ports 23 with the exhaust chamber (i that is provided at or about its center with an exhaust outlet `24, Figs. 3 and 5, leading off to one side. rllhe cut away portion, port or passage 22 ot each oscillatory low pressure valve 21 works first to the adjacent steam connecting passage 3 and then to the exhaust.

In the operation of the engine the valve action begins by the steam valve l2, say at the upper end of the high pressure cylinder, admitting steam above the piston 25 of that cylinder. Then the out ol takes place and the steam is allowed to expand as usual to very near the end of the downward stroke of the piston. In the meantime the piston 26 in the low pressure cylinder moves upward exactly as the other piston 25 moves downward, they being balanced in stroke one against the other both in movement and weight, that is, the two cranks, pistons `and rods are always in exactly opposite `positions in stroke. N'Vhen the low pressure piston in moving upward, reaches the point for com- IOO IIO

sequently the passage 3 -contains steaml at higher pressure than that of exhaust, and,

therefore, as the lowpressure piston v26 Ivs moves upward against compression it reaches,"

or about reaches, the. pressure*y in the connecting passage at the' time when the valve 21 opens to it.` Then the compression continues in the low pressure cylinder 2 until the period for exhaust lead from the -high pressi ure cylinder which is thus added to the com pression at the end of the vstroke in the low pressure cylinder.` This gives three stages to the compression in the low pressure cylinder and insures a vperfect balance of the steam between the twocylinders, at the beginning of each stroke. These threestages are, first,

, the closing of theexhaust port from the low pressurecylinder; second, the openingof the low-pressure cylinder port tothe connecting passage 3 between the cylinders, and, third, the opening'of the exhaust from the high pressure cylinder 1 which becomes really the steam opening for the low pressure cylinder 2 and determines `the lead of steam for that cylinder.' n, n

The length of the low press-ure cylinder port 2O and cut-away portion 22 of the valve 21, as shown in Fig. 4, areeach greater than the corresponding ports at the high'pressure cylinder, as the low pressure cylinder itself is of much greater diameter than the other cylinder. Thus the connecting passage 3 between the two cylinders tapers from the valve Y seat of onetothat of theother and affords a very free outlet for steam from the high press urecylinder to the low pressure-cylinder. n

The close and compact arrangement of the cylinders 1 and 2,'initial `steam chamber-4, exhaust chamber and closed interspaces 5 and 7 and thetemployment of the oscillatory vvalves 12 and 2l in the connection and relationv to each other as hereinb'efore described,

withthe simple and direct connecting passages 3 between the two cylinders and the high pressure exhaust vlead controlling the low pressure steam lead, may be noted as imp portant features of the present invention.

. this general character.

of the engine.

pressurevalves y12, and also the grooved or slotted cut off plates A and their connections 31 with a quadrant or auxiliary wrist plate 32, movable upon the same axis with the main wrist plate but entirely independent from it, are allsubstantially the same as shown, described and claimed in Letters Patent No. 498,634, granted to me May 30, 1893, except that a connection, in some places, takes hold outside its bearing instead of inside, to better accommodate the action of the parts to the vertical condition. The main wrist plate ,27 is connected by rods or connections 33 to rigidly attached arms 34 on the stems of the low lpressure valves. V

The high pressure valves 12 and low pressf ure valves'21 'are oscillated from the main wrist plate 27 which receives its motion through a rod 35 that connects with the free end of an arm 36 on a rock-shaft 37, Figs. 1 and 2. This rockshaft 37 is provided withanother arm 38, Fig. 1,/ having a ball and socket connection with one end of a rod 39 that connects atits other end with a counterbalanced and weighted main rocker arm 40 vto which motion is communicated through a rod41 from an eccentric 42 on the main shaft The counter-balanced main rocker arm 40 isfulcruned to the engine frame at 43, intermediate the ends of said arm.. On the engine frame, as shown in Fig. 1, is a bracket 43a by which the fulcrum of the rocker arm is supported. The'rod 39 is pivotally connected with the main rocker arm 40 near one end of the saidarmand the other end of the rocker arm is provided with a counter-balance 44 preferably in the form of anv integral hollow ball or other suitably shaped chamber or cavity to be filled with lead or-'other weighty material, as needed. The rod 41 from the main eccentric 42 to the counter-balanced main rocker arm 40 has its connection on the rocker' arm at a point between and sufficiently below aldirect line be? tween the centers ofthe fulcruml 43 and end of the rod 39, on the line of an arc through where the connection to eccentric rod would ordinarily be, tocorrect the angular advance of the eccentric and rod .in relation to each other and bring the `movement of the valve gearing into the same time for reaching each degree of.A its advance in either direction, or going from the center in either way of movement. This, therefore, makes the movements of the valves the same in both the up and down strokes.

The cut off at the high pressure valves 12 is effected through the quadrant or auxiliary wrist plate 32 that is movable upon the Same axis as the main wrist plate n but entirely independent thereof. This auxiliary ywrist plate 32 is actuated through a rod 45, Figs. 1, 2 and 9, one end of which has a ball and socket connection with a crank arm'4G on oneend of a rock shaft 47 supported in suitable bearings on the engine frame. To ,the other end ofthe rock shaft 47 is secured rocker arm 40, as shown in Fig. 2.

a crank arm or equalizer lever 4.8, Figs. 9 and 10, the outer side oi. which is provided with a longitudinal groove 49 in which slides a pin or block 50 carried by one end of an auxiliary, or cut ott, rocker arm 51 that is fulcrumed at 52, about midway its length, to the engine frame. It will be seen that `the groove 49 and pin-or block 50 form a variable connection between the equalizer 48 and one end of the auxiliary rocker arm. To the other end of this auxiliary rocker arm or lever 51 is pivotally attached one end of a rod 53 the other end of Which is bifurcated to receive a slide block 54 that is pivotally supported therein, as shown in Fig. 9. This slide block 5-1 is loosely engaged in a segmental slotted link 55 one end of which is fulcrumed, through a pin 5G, to the un- Weighted end of the counterbalanced main To the other end-of the slotted link 55 is pivotally attached a rod 57 that is connected `to and actuated `from the cut off eccentric 5S on the engine shaft.

As in other engines of the `Corliss type the point of out oli. is determined by a governor. The mechanism through which this is effected will now be described. A pendulum lever 59, Figs. 1,2 and 9, is suspended at G0 from a bracket Gl on the engine frame immediately behind the center of movement of that end of the rocker arm 5l to which is attached `the rod 53 connecting with the slide block 54 in the slotted link 55 that is actuated from `the cut od eccentric. The lower end of the pendulum 59 is provided with a longitudinal slot 62, Figs. 2 and 9, in which plays up and down a subsidiary slide block G3 mounted `on the extended end of a pin G4, passed through the link slide block 54, and by which the two slide blocks are connected. This allows full play up and down for the slotted link 55, while the position in it of the slide block 54 fordeterminingcut oft is held secure. For the purpose of shifting the link slide block 54 to and from the link fulcrum 56 to vary the point of cut ott the pendulum 59 is moved into proper position by an oscillatory plate 65, Figs. 9 and 11, pivotally supported from a bracket 66, Fig. l, on theengine frame. In the face of the oscillatory plate is a helical cam groove or slot 67 that engages with a pin or roller G8 on the pendulum. To the rear side of this oscillatory plate 65 is secured a pinion 69 engaged with areceiprocating rack bar through which the helical cam plate 65 and pendulum 59 are actuated from any suitable governor. The shorter end of the oscillatory cam plate 65 may be counter-balanced at 71 as shown in Figs. 9 and ll. By suspending and arranging the pendulum 59 in the manner shown and described it is afforded a range of movement at all times directly in line with the rod 53 connecting the auxiliary rocker arm 5l with the link slide block 54 through the position of which in the slotted link 55 is determined the point of cut olf for the valves of the high pressure cylinder. The plate G5 with its helical cam groove or slot 67 is oscillated in one direction or the other by the rack 70, actuated from the governor, and the pendulum 59 is thus moved one Way or the other, controlled by the pin 68 in the cam groove G7, and carries with it the link block 5-1 to a longer or shorter position for cut od. As the pin 68 fitting in the helical cam groove G7 is in direct line with the pivotal bearing ot the pinion 69 and plate 65 the resistance is against that bearing and does not have any appreciable tendency to react upon the governor.

I may employ a governor driven directly from the main shaft of the engine through gearing 72 and upright shaft 73, Fig. 2, but as the particular form of the governor is not essential and forms no `part of. my present invention its illustration here is `not deemed necessary.

It will be observed that the balancing, throughout the engine, is part against part Where practicable and otherwise counter-balanced. This balance of the several parts includes everything from the pistons, rods and cranks to the valve gear and wrist plate connections, the rocker arms, the equaliziug and governing mechanism for the cut off and, also, the smallest minutire of the distribution of steam.

What I claim as my invention isl. In a compound engine, the combination of a high pressure cylinder and a low pressure cylinder placed side by side in compact close relation to each other and provided at both ends with direct steam connecting passages formed in the cylinder casting and leading from the exhaust ofthe high pressure cylinder to the induction ofthe low pressure cylinder, an initial steam chamber and an exhaust chamber intermediate said cylinders, and cylindrical oscillatory valves at both ends of both the high pressure andthe low pressure cylinders and located between the said cylinders, each valve adapted to control both the induction and eduction of its cylinder and the valves at the ends of the high pressure cylinder being also adapted to control the lead of steam to the low pressure cylinder, substantially as described.

2. In a compound engine, the combination of a high pressure cylinder and a low pressure cylinder placed side by side in compact close relation to each other and provided with direct steam connecting passages leading from the exhaust of the high pressure cylinder to the induction of the low pressure cylinder, an initial steam chamber and an exhaust chamber intermediate said cylinders and each provided at both ends with cylindrical valve seats, and cylindrical oscillatory IIO being arrangedV to govern the admission of steam to the love'r pressure cylinder from the exhaust lead of the high pressure cylinder,

substantially as described.

3. In a compound engine, the combination of a high pressure cylinder and a low pressure cylinder placed side by side in compact close relation to each other, an initial steam chamber and an exhaust chamber intermediate said cylinders and alternating with intervening closedrspaces, both ends of the cylinder-casting being provided between the cyllnders with cylindrical valve seats located at the high pressure and low pressure cylinders and with direct steam connecting passages leading from the exhaust of the high pressure cylinder to the induction of the low pressure cylinder, and cylindrical oscillatory valves 1ocated in'saidvalve seats at both ends'of and betweenthe cylinders, each valve being adapted to control both the induction and eduction of its cylinder and the valves at the high pressure cylinder controlling also the lead of steam to the low pressure cylinder, substantially as described.

.4. In a compoundv engine, the combination w1th a high pressure cylinder and a low pressure cylinder placed in compact close relation to each other and having direct steam connecting passages tapering from the ports of the high pressure cylinder to the ports of the low pressure cylinder, whereby the clearance between the cylinders and through the valves is reduced and afree outlet afforded for the kpassage kofwsteam fromy the high pressure cylinder to the low pressurecylinder, of val-ves located between `said cylinders and each adapted to control both the induction and eduction of its cylinder, the valves at the high pressure cylinder being also adapted. to con.- trol the lead of steam at the low pressure cylinder, substantially as described.

5. In a compound engine, the combination of the high pressure cylinder and the low pressurecylinder placed side by side in compact close relation to each other and provided at both ends with direct steam connecting passages and with cylindrical valve seats located at both ends of and'between the cylinders, cylindrical oscillatory valves for both ends vof each cylinder, located in said valve seats betweenthe cylinders and each adapted tocontrol both the induction and eduction of its cylinder a single main' wrist plate intermediate the cylinders', and valve gear and'wrist plate connections through which all the said valves controlling the ports of both the high pressure and low pressure cylinders are actuated, substantially as described. 6oA

6." In a compound engine, the combination with the high-pressure cylinder and the low pressure cylinder placed in compact close relation to each other and having direct steam connecting passages, of an initial steam chamber and an exhaust chamber located between said cylinders and having cylindrical valve 7. In a compound engine, the combination with the high pressure cylinder, the low pressure cylinder, their cylindrical oscillatory valves, a single main wrist plate and the valve gear and wrist plate connections, of a counter-balanced main rocker yarm actuated from an eccentric on the engine shaft, arock shaft provided with arms, a rod connecting one arm of said rock shaft with the main rocker arm on one side of its fulcrum and at a point opposite its counter-balanced'end, and a rod connecting the other arm of said rockshaft with the main wrist plate, substantially as described.

S. In a compound engine, the combination with the oscillatory valves, the main wrist plate, and the valve gear and wrist'plate con- 'n nections, of a counter-balanced main rocker arm fulcrumed intermediate its ends, a rock shaft provided with arms, a rod connecting oney arm of said rock shaft4 with themain rocker arm at a point opposite its counter balanced end, an'eccentric rod extended from an eccentric on the engine shaft andconnected. with said counter-balanced main IOO rocker arm at a point between and below the rocker arm fulcrum and the attachment ofv the rod connecting with the rock shaft arm,

andanother rod connecting the other arm of said rock shaft -with thev main wrist plate, substantially as described.

IIC

9. In a compound engine, the combination I with the oscillatory valves, the main wrist plate and the valve gear and wrist plate counections, of a counter-balanced mainV rocker arm actuated from an eccentric on the engine shaft and connected with thel said main wrist plate, a slotted link carried by said main rocker arm and actuated from the cut olf eccentric, al blockadapted to slide in said link, a cut o mechanism connected with and actuated from said block, a slotted pendulum,a block adapted to slide in the slot of the pendulum and connected with Ithe, slide block of the slotted link, au oscillatory plate having a cam groove or slot `engaged with a pin on Ythe pendulum, and rack and piniongearing .for actuating saidcam plate and pendulum vfrom a governor to vary the position ofthe link slide block and determine the point of lcut off, substantially as described.

10. The combination with an'oscillatory valve, a main wrist plate, thevalve gearvand wrist plate connections,a counter-balanced main rocker arm connected with the said main Wrist plate and actuated from an eccentr1c on an engine shaft, a slotted link fulcrumed to said main rocker arm and actuated from a cut oit eccentric, and ablock adapted to slide in said link, of a balanced centrally fulcrumed auxiliary rocker arm having one end connected with said block, a pivotally supported equalizer lever having a varying connection with the other end of said auxillary rocker arm, and cut off mechanism connected with said equalizer lever, substantially as described.

l1. The combination with `an oscillatory valve, the main Wrist plate, a valve gear and Wrist plate connections, of a counter-balanced main rocker arm actuated from a main` eccentrie rod, a two armed rock shaft intermediate the main wrist plate and main rocker arm and connected with both by rods, a slotted link carried by the main rocker arm and actuated from the cut oft eccentric rod, a slide block supported in said link, governor mechanism connected with the said slide block to control 1ts position in the slotted link and determine the point of cut oft, a balanced auxiliary rocker arm having one end connected with the link slide block, an equalizerlever having avarying connection with the other end of the auxiliary rocker arm, and a quadrant or auxiliary wrist plate connected with said equalizer and with the cut oit plate that coutrols the action of the valve gear, substanltially as described.

l2. The combination with an oscillatory Valve, a main Wrist plate, the Valve gear and Wrist plate connections, the out ott plate and its auxiliary Wrist plate, of a counter-balanced lnain rocker arm actuated from a main eccentric and connected with the main wrist plate of the valve gear, a link carried by said main rocker arm and actuated from the cut oft eccentric, an auxiliary balanced rocker arm intermediate said link and the auxiliary Wrist plate, a link slide block connected with one end of the auxiliary rocker arm, equalizer mechanism intermediate of and connected with the auxiliary rocker arm and auxiliary Wrist plate, and governor mechanism connected with the link slide block to determine the point of cut off, substantially as described.

13. The combination with an oscillatory valve, its valve gear, main Wrist plate and wrist plate connections, ot a counter-balanced main rocker arm fulcrumed intermediate its ends and connected with the main Wrist plate and main eccentric rod, alink carried by said main rocker arm and actuated from the cut oft eccentric rod, a block adapted to slide in or on `said link and controlled by a governor, a Vcentrally fulcrumed and balanced auxiliary rocker arm having one end connected with said block, an equalizer lever having a varying connection with the other end of said auxiliary rocker arm, and means for connecting the equalizer lever with a cut oit1 quadrant or tions, a main rocker arm connected with a p main wrist plate and actuated from the main eccentric rod, a link carried by the main rocker arm and actuated from the cut ott eccentric rod, and a link slide block, of a centrally fulcrumed and balanced auxiliary rocker arm connected With the link slide block and with a cut oit mechanism,a slotted pendulum lever, a slide block located in the slot of the pendulum and connected with the link slide block, an oscillatory plate having a helical cam groove or slot engaged with a pin or roller on the pendulum, and rack and pinion gearing actuated from a governor to oscillate the cam plate and pendulum for shifting the link slide block and controlling the point of cut ott, substantially `as described.

l5. The combination with the cylinders, balanced pistons, cranks, rods, valves and valve gear of a compound engine, of a coun ter-balanced main rocker arm connected with the main wrist plateot' the engine valve gear and actuated `from the main eccentric rod, a link carried by said main rockerarm and actuated from the cut oft eccentric, a link slide block, a balanced and centrally fulcrumed auxiliary rocker arm having one end connected with the link slideblock and its other end with an equalizing mechanism through which the cut oit devices are actuateda pendulum provided with a slide block that is engaged with the link slide bloek,a eounterbalanced voscillatory cam plate engaged with the pendulum,and gearing for actuating said cam plate and pendulum from a governor to vary the position of the link slide block Aand control the point ot' cut ott, substantially as described.

16. The combination Withavalve, its valve gear, a eut oft plate that controls the action of the valve gear,arocker arm actuatedfrom a main eccentric and connected with the valve TOO IIO

gear, a link carried by,said main rocker arm and actuated from a cut-off eccentric, a block adapted to slide in or on said link, and connections from said block to the cut oit plate, of a slotted pendulum, a block .adapted to slide in the slot of the pendulum `and connected With the link slide block, an oscillatory plate having a cam groove or slotengaged with a pin on the pendulum, andrack and pinion gearing `for actuating said plate and pendulum from a governor, to vary the position of the link slide block and determine the point of cut oft, substantially as described.

17. The combination with a valve, its valve gear and cut oft connections, a main rocker arm connected with the valve gear and carrying a link that is actuated from a cutoff eccentric and provided with a link slide block 'for controlling the cut olf connections, of a pendulum for shifting the position of the link slide block to control the point of cut oit, and

an oscillatory cam plate engaged with the pendulum'and-actuated from a governor, substantially as described.

18. The combination with a valve and its valve gear and cut o devices comprising a link slide block for controlling the point ot' cut H, of a slotted pendulum., a slide located in the slot of the pendulum and connected with the link slide block, an oscillatory plate having a helical cam groove or slot engaged with a pin o r roller projecting lfrom the pendulum, and means for actuating said cam plate and pendulum'from a governor to shift the link slide block and vary the pointof cut off, substantially as described.

19. In a compound engine, the combination with a high pressure cylinder and a low pressure cylinder placed close together and having v direct steam connecting passages leading from the exhaust of the high pressure cylinder to the induction of the low pressure cylinder, of induction and eduction valves lo cated between said cylinders, the valves at the high pressure cylinder controlling the lead oft-steam to the low pressure cylinder -from the exhaustlead of the high pressure cylinder and the valves at the low pressure cylinder controlling the exhaust therefrom,

pistonslocated in said cylinders and balanced in stroke one against the other, both in movement and weight, valve gear and wrist plate connections, andI a governor controlled cutoff, whereby the lead and compression of steam are determined and aE balancing of steam pressure is obtained through and `between the cylinders and connecting passages at beginning and end of each stroke, substan-I slide and vary the point of cut-off, substantially as described. Y

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses. p

` JOSIAH DOW.

Witnesses:

I. AL'rz GATES, CHARLES H. WEISS..y

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