US260522A

US260522A - Valve-gear

Info

Publication number: US260522A
Authority: US
Publication date: 1882-07-04
Anticipated expiration: 1899-07-04

Description

(No Model.) 5 sh'eets-shet v3..

I 'JfBARRETT I VALVE GEAR.

120.260,522. --Patented July 4, 1882.

(No Model.) 5.Sheets-Sheet 4.

J.BARR ETT. VALVE GEAR'. A

No. 260,522. Patented July 4, 1882.

MFLESEL n I i 'WEILDIL A r y Wr? N. PETERS. Pima-Lixhogmpher, wmhingw. ILC.

(No Model.)

l Y 5 Sheets-Sheet. A J. BARRETT. VALVE GEAR.

Patented July 4, 1882.

N.4 PETERS. Phuwmhosmher. washinglon. D. c.

UNITED STATES -`PATENT OFFICE.

J OSIAH BARRETT, OF PITTSBURG, PENNSYLVANIA.

VALVE-GEAR.

SPECIFICATION forming part of Letters Patent No. 260,522, dated July 4, 18,82.`

Application filed November 16, 1881. (No model.)

To all whom it may concern:

Be it known that I, JosIAH BARRETT, of Pittsburg, in the `county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Valve-Gear for vSteam-Engines; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawings, forming a part of this specification, in which Figure 1 is a front elevation of asteam-engineillustratin g my invention. Fig. 2 is a detached rear View, illustrating the movement of the apparatus for operating the cam-rods. Fig. 3 is a cross-section of the apparatus on the linear x, Fig. l. Fig. 4 is a face view of the variable cams, the cam-rod being removed and only the idle-wheels of the spring-pawls being shown. Fig. 5 is a vertical cross-section of the variable cams and connecting-rods; Fig. 6, a detached top view of the variable cams and connecting-rods. Fig. 7 is a side view ofthe cam-rod and its pawls. Fig. 8 is a detail view, showing the vibratory movement of the cut-off. Fig. 9 is a detached perspective view of a modification ofthe cut-off apparatus. Fig. 10 is an enlarged front view of the cylinder end of the steam-engine shown in Fig. 1. v Like letters of reference indicate like parts in each.

My invention relates to apparatus for operating the valves of steam-engines, and has special reference to heavy mill-engines and the engines used on steamboats and vessels,known as river-engines." f

It consists, rst, in improved apparatus whereby the supply of steam to the engine can be regulated to cut off at a full stroke or any required part thereof, heilig varied at the will of the operator during the movement of the engine, if so desired second, in apparatus for imparting from the pitman of the engine the desired movement to the. rod which operates the valve apparatus; and, third, in certain improvements in the construction of'the apparatus employed.

To enable others skilled in the art to make and use my invention, I will describe its construction and operation.

In the drawings, Arepresents the steam-cylinder, B the piston-rod, C the pitman, and D the paddle-wheel or ily-wheel shaft, of an ordinary steamboat-en gine, neither paddle-wheel nor fly-wheel being shown.

The cylinder A has the ordinary steam-supply pipe,-A', and steam-exhaust pipe back of it, (not shown,) and the supply-valves a a.' and exhaustvalves (not shown) on the opposite side above the cylinder, the supply-valves being opened by the supply-valve rods a2 c3 and the exhaust-valves by the exhaust-valve rods e c'.

supply-lifter F,-whicl1 is rigidly secured to a shaft mounted in suitable bearings above the center of the cylinder A and turned by means of an arm, f, secured thereto. The exhaustvalve rods e c' are lifted by the exhaust-lifter G, which works loosely on the supply-lifter shaft, and is provided with au arm, g', conuected by a rod with an arm secured toa shaft mounted above the cylinder at the side of the supply-lifter, said shaft having an arm, g, conthe cam-rod, are of vthe usual construction on river-engines and are operated' in the usual manner.

Secured to either side of the slide b, on which the T-head B' of the piston-rod Works, are the uprights I', at the top of which is mounted the shaft i, to which the pendulum I is secured, the lower end of this pendulum sliding in a socket, b', pivoted on the T-head B', so that as the T-head moves back and forth on the slide b a vibratory'motion is imparted to the pendulum and through its shaftto the crank-arm i'.

The cam-rod is divided into several parts, H, H', and H2, the part H being pivoted to the crank-arm g and to an upright pivoted bar, h, by which it is held in proper position, and the Apart H extending back to the reversing apparatus K, referred to hereinafter, while the part H2 connects with the cam on the paddle- 'wheel shaft or to other operating apparatus, as

hereinafter described. A

Mounted on a shaft extending from the back of thecamrod H is the cut-off frame L, having an arm, L3, extending atrrght angles therefrom, which arm is connected to the crank-arm t" of the pendulum-sbatte' by a rod, 2,so that the motion obtained from the pendulum is imparted to the frame L. A long slot, Z', is formed .in this frame L, in which slot a slide, l, is mounted, part of the slide Workingon the back of the frame, and having an extension carrynected to the cam-rod H. These parts, except The supply-valve rods a2 a3 are lifted by the YOO IOS

ing a pin or spindle, l2. The pin Z2 is supported on the extension in such position that on the longitudinal movement of the slide L in the slot l' the pin is held approximately inline with the shaft on which the frame is pivoted, so that on the vibration of the frame the pin, being at or near the pivotal point of theframe, has little motion, except a partial rotary motion, it being arranged in this manner for the reason hereinafter shown.

. Mounted on the same shaft with the frame L are the cut-ott cams M M', each cam being substantially a quarter arc or segment ot' a eircle, the lower edge of which is slightly curved oft'. The cams are connected tothe slide Z by means ot' arms m, pivoted to both cams and slides, being so arranged that the cams are spread out or folded past each other upon the movement of the slide in the slot l', and the cut-oil' being by means of these variable cams changed at the will of the operator. This variation of the cut-olf cams is obtained by means ot'a rod, n, connected at the bottom to the pin l2 ofthe slide l and connected at the top to an arm on a shaft, N, extending across the top of the engine-room, or otherwise supported above the engine, this shaft N being turned to vary the cut-oli' by anysuitable apparatus, N,within the reach of the engineer.

Mounted on the front ot` the cam-rod H is a slide, p, which is generally formed in the shape of a. block adapted to slide back and forth along the cam-rod, and a rod, P, extends from this sliding block p to the arm f, which operates the receiving-lifterF, so that on the movement of the block p the receiving-valves a a' are opened or closed, as desired.

Pivoted to the cam-rod H on either side of the shaft carrying the cut-oil` cams M M' are the spring-pawls R R', which operate in the front of the cam-rod in the course of the sliding block p, so as to hold the block and cause the cam-rod H to draw the rod P back and forth with it during all of its movement when a full stroke is desired, and during part when the cut-oil` cams are arranged to withdraw the pawls.

The pawls are held out, as above described, by the springs r', except when drawn back by the eut-oft` cams M M', which is accomplished when either eut-olic cam M or lvl/,on its vibration, comes against a pin or idle wheel, r, on one of the pawls and withdraws either pawl out of the course of the sliding block. As soon as the sliding block p is thus freed from the pawl there is no force to sustain the suppl y-litter F, and the weight of the suppl y-valve rods a2 or 0.3 presses down the supply-lifter and closes or cuts oi the steam-supply before the stroke is finished, the expansion of the steam carrying the piston the balance of the stroke.

On the side or face ofthe pitman C, at about the center of the pitman, is secured a plate, C', having a long straight slot, c, formed therein.

Mounted in a suit-able journal on the bedframe of the engine is the rock-shaft S, which has at each end a pivoted block, one block of which fits into the long slot c on the pitman and the other block ts into the slotted or forked arm t of the double crank T, the other crank, t', ot' which is connected with the part H2 of the cam-rod.

A slide-rod may be secured to the pitmau instead of the slot formed therein, and a slide connected with the rock-shaft be mounted thereon; and thisl consider equally within my invention.

Upon the movementot` the pitman back and forth at each stroke of the engine, as it rises and falls in converting the longitudinal into rotary motion, the end of the rock-shaft S piv oted in the slot c is raised and lowered thereby, and at its opposite end imparts the reverse movement to the slotted arm t ot' the double crank T, which causes a rocking movement of the double crank, and through the crankarm t' draws the cam-rods back and forth, imparting to them the same movement as is usually obtained from the cam and cam-yoke on the paddle-wheel shaft. As the pivoted block at one end of the rock-shaft slides in the slotted arm t of the double crank T, it is evident that f it imparts the quickest movement to the crank Twhennearthcbaseot'theslot. Bythismeans the quick movementncccssary to open and close theengine-valvesis imparted through the crank to the cam-rod when the pivoted block is near the base of the slotted arm t, and comparatively little movementis imparted to the crank when the pivoted block is at the end of the slotted arm,the quick movement therefrom heilig only obtained when desired.

The reversing apparatus K shown is that ordinarily known as theStephenson Reverse, there being a slide-rod, K3, pivoted ou a standard secured to the engine bed-frame, and a block, K', sliding thereon, this block K' having a piu on which the back end of the cant rod H' works, a rod, K2, being also pivoted thereon, and connecting with one arm, il, of au elbow, U, pivoted at u2 to the bed-frame. The other arm, u', ot' the elbow connects with a rod, a3, extending forward to the throttle in proper position for operation by the engineer, and is connected to one arm of a double crank, V. This crank has usually been operated by a hand-lever; but it often happens that'on attempting to reverse the steam-pressure acts against the reversing of the apparatus, andthe strength of the engineer is not sufficient to accomplish it. I have therefore formed the one arm c of the double crank V in the shape ota segmentof acircle havingits periphery cogged, and have mounted on a standard above the cogged segment a pinion, v', meshing into the eogs ot' the segment and turned by a handle, c2.

To reverse the engine the pinion is rotated, and thus throws the crank V forward, and through the rod a3, elbow U, and rod K2 raises the block K' on the slide K3 until it is raised past the pivotal point ot' the slide, thus causing the reversing ot' the apparatus.

The apparatusis locked by means of a springcatch, w, on the handle c2, which catches in a IOO IIO

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seat, w', on the cogged segment v ,in whichever position the apparatus is arranged. Y The force necessary to reverse is thusgreatly reduced and the apparatus arranged to be wholly within the control of the engineer. The apparatus shown is Varranged as one'of two engines to be used on a steamboat or vessel,-the paddle-wheel operating as the ordinary ily-wheel and overcoming the dead-point, and the shaft N has connected to it the cutoff-regulating apparatus of the opposite engine, so that the cut-oft apparatus of both engines can be changed or varied by the engineer from one place and at the 'same time..

My improved valveoperating apparatus Works in the following manner: The supplyvalve t at the front of the cylinder is opened by means of the supply-lifter F, which raises the valve-rod a2, the lifter F being held in position through the arm f, rod P, and slide lo, which presses against the spring-pawl R. At the same time the rear exhaust-valve is opened through the exhaust-lift Gr and exhaust-valve rod e. Steam having been admitted, it forces back the piston, and through the piston-rod -B the pitman C, the pitman raising the paddlewheel crank, and of course being raised at an angle to the piston-rod. During the backward movement of the pitman the forward end, s, of the shaft S, by its block fitting in the slot vor groove c, is rst slightly raised 5 but as soon as the back end of the pitrnan passes its highest point and begins to descend `the end s of the rock-shaft S is lowered, consequently lifting the back end,-s, of the rock-shaft, which, by its block sliding in the slotted arm t of the double crank T, at the proper time, by the quick motion obtained as above described, raises this arm, and by the arm t draws back the eamrods H2, H', and H, the cam-rod Hbeing connected with the exhaust-valveapparatus, and through the arms g and goperates the exhaustlitter G, opening ,the forward exhaust-valve ready for the next stroke. During the backward movement ofthe piston the pendulum is swung backward by the pivoted socket b', and through the arm t', rod t2, and'arm La vibrates or tilts the frame L and cut-off cams M M over toward the rear, causing the cam M to press against the idle-wheel r on the springpawl R', withdrawing the paw] and freeing the block p, so that it can slide in a backward direction over the pawl, when, as the rod P no v longer supports the supply-lifter F, the lever a2 presses down thelifter and closes the valve, the

, block p sliding along the cam-rod over the pawl shaft S, and by its rear arm, s', lowering the slotted or forked arm t of the double crank T, which by its arm t', at the proper time, draws forward the'cam-rodys, so as to open the rear exhaust-valve by means of the valve-rod e', and also theforw'ard supply-valve, a, at the end of the stroke. In the meantime the pendulum, swinging forward, by means of the connections, vibrates or tilts the frame L and cutol cams M M over toward the front, causing the cam M to press against the idle-wheel r on the spring-paw] R, withdrawing the pawl and freeing the sliding block p, so that the weight of the rear suppl y-valve rod, a3, will press down the supply-lifter F, thus closing the supplyvalve and causing the slidep to slide forward over the pawl R along the cam-rod, where it rests till caught by the. pawl R on the forward movement of the cam-rod, the pawl R having been thrown out by the spring as soon as freed by the tilting of the 'cut-offcams; rlhe stroke is then repeated, the apparatus operating in the manner above set forth. If the. usual cam on the paddle or ily wheel shaft is employed, the movement of the cam-rods is obtained therefrom in the usual manner.

In order to vary the cut-off so that steam is supplied to the piston during the full stroke, or is cut offat any desired part of the' stroke,

the cut-o fl'eams M M are closed together or spread open, so as to operate on the springpawls R R' at any desired time of the stroke. This is accomplished by means of the rod a and its connections, as above described. To spread the cams so as to cut oil' earlier in the stroke, the rod n is forced down, and, drawing on the slide l by the pin Z2, causes the arms m to press out and spread the cams, and as the frame L is vibrated the cams come in contact with the pawls, free the sliding bar, and cutoff the supply-valve earlier in the stroke; and to give more steam to the piston the rod n is raised, so as to fold the cams past each other and cause them to trip the pawls and cut otl' later.

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By folding the cams past-each other, so that they do not trip the pawls, the pawls hold the slide p and canse it to move with the cam-rod H, thusgiving a full stroke.

The slide Z is arranged to support the pin l2 approximatelyY at they pivotal point of the frame, so that little or no motion is imparted to 'the rod by the vibration of the cam-frame, and as its force is exerted at the dead-point of the frame, it can operate to vary the eut-off cams during the motion of the apparatus. As thecut-olf apparatus ot' both engines is secured to the same operating-shaft, they can both be varied at the same time by one operation.

.lt is evident thatthe exact forni of the cutoft'cams may be varied, and that they may be supplied with arms or supplemental devices for tripping the pawls.

In Fig. 9 is shown a modification of my improved cut-off apparatus, by which the valves are prevented from dropping when cut off, this dropping ofthe valves wearing away the packing and causing a jar to the machinery. In it the slide p is made in the form of ayoke, which slides on the cam-rod H, and is provided with an idle-wheel, p' p2, on either side of the cutoff cams M M'. The cams are of substantially the same shape, the lower edges being curved in slightly more, and they are vibrated by the same apparatus, the relative time of their vibration being slightly altered. The supplylifter F is connected to the slide p by the same rod I. On the operation of the engine with this form of eut-off the cams are vibrated by the pendulum I, so as to hold the'supply-valve open by the edge of one cam pressing against the idle-wheel p' or p2 until the time to cut ofi', when the cam is raised so that the idle-wheel runs down the lower curved edge of the cam and causes the valve to fall without shock. 'Io arrange the cnt-oft' for full stroke, it is spread so as to hold the slide p and cam-rod together, the idle-wheels playing up and down the cams as they are vibrated.

No claim is made herein to the special apparatus shown in this modification, as it will be made the subject of another application.

Where it is desired to regulate the cut-od' by means of a governor, as is sometimes done in stationary mill-engines, this can be accomplished by connecting the rod n with the governor, the motion of which will thus operate to spread out or fold together the cams M M' and vary the cut-O as desired.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In combination with a cam-rod operating the exhaust-valves of a steam-en gine, a cut-olf located on the cam-rod and a slide mounted on the cam-rod and connected with the supplyvalves of the engine, substantially as and for the purposes set forth.

2. In combination with a cam-rod operating the exhaust-valves of a steam-engine, a vibrating cut-o1 pivoted on the cam-rod and a slide mounted on the cam-rod and`connected with the supply-valves, substantial] y as and for the purposes set forth.

3. A cnt-ott for steam-engines formed of two segmental cams adapted to be spread out or folded together to vary the eut-od', substantially as and for the purposes set forth.

4. The variable cut-011' cams M M', mounted in the frame L, in combination with the slide l and rods m m, substantially as and for the purposes set forth.

5. The variable eut-olf cams M M', mounted in the pivoted frame L, in combination with the rods m m, slide l, having spindle l2 approximately at the pivotal pointof the frame, and apparatus secured to the spindle foroperatin g the slide, substantially as andffor the purposes set forth.

6. In combination with the variable cnt-olf cams M M', mounted on the pivoted frame L, the rods m m, slide Z, carrying a spindle, L2, approximately at the pivotal point of the frame, shaft N, and rod u, connecting-the spindle of the slide with the shaft, substantially as and for the purposes set forth.

7. In combination with apendulum operated by the stroke of the engine, a cut-off pivoted on the cam-shaft, and connecting mechanism, whereby a vibratin g motion is imparted to the cutoff, substantially as and for the purposes set forth.

8. The combination of the cut-oli' frame L, pivoted on the cam-rod H, and having an arm, la, the pendulum-shaft z', having an arm, i', rod

i2, and pendulum I, substantially as and forV the purposes set forth.

9. The cam-rod H, having the spring-pawls R R',in combination with the slide p and cutol' apparatus for operating the pawls, substantially as and for the purposes set forth.

10. The combination of the cam-rod H, connected with the exhaust-valve apparatus, slide p, sliding thereon, and connected with the supply-valve apparatus, and a cut-off mounted on the cam-rod to operate the slide, substantially as and for the purposes set forth.

11. The combination of the cam-rod H, slide p, mounted thereon, spring-pawls R l', and vibrating cut-olf cams M M', pivoted on the cam-rod, substantially as and for the purposes set forth.

12. The combination of the pivoted cut-oli1 cams M M' and spring-pawls R It', having tripping devices 1' in the line of movement of the cams, substantially as and for the purposes set forth.

13. In combination with the pitman C, having the slot c, the rock-shaft S, working in the slot c, whereby, on the rising and lowering of the pitman, a rocking motion is imparted to the rockshaft to operate the cam-rod of the engine, substantially as set forth.

14. The combination of the pitman C, having the slot c, crank T, having the slotted arm t, and rock-shaft S, working in the slot c and slotted arm t, substantially as and for the purposes set forth.

15. The combination of the engine-pitman U, having slot c, the double crank T, having arm t', connecting with the cam-rod and slotted arm t, and therock-shaft S, workingin the slotc, and slotted arm t, substantially as and for the purposes set forth.

16. In combination with the reversing apparatus K, the double crank V, having the cogged segmental arm e, the pinion a', and the handle v2, substantially as and for the purposes set forth.

17. In combination with the reversing apparatus K and double crank V, the cogged segmental arm fv, having the locking-seats w', pinion n', and handle e2, having the springcatch w, substantially as and for the purposes set forth.

In testimony whereof I, the said J osIAII BARRETT, have hereunto set my hand.

Witnesses: JOSIAH BARRETT.

JAMES I. KAY, F. G. KAY.

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