US45199A - Improvement in steam-engines - Google Patents

Description

that a perfect parallelism of the axes ofthe and exhaust-valves of theengineyby means ot' the exhaust-valve; gear on anenlarged scale.

sal joint attached to the head.

vwith sliding or partly rotative steam and ex- UNITEDv STATES PATENT OFFICE.

IMPROVEMENT IN Specification iorming part of- Letters Patent No.

STEAM-ENGINES.

45.199. dated November 22, 1864 antcdate November 9, 1864.

.T0 all whom it may concern:l

Be it known that-Lis. LLOYD WTEGAND, of the city of Philadelphia and State of Pennsylvania-have invented certain new and useful Improvements in Steam and Pneumatic Engines; and-*I do hereby declare that the following isa full and exact description there-- of, reference'being had to the drawingsannexed and making part of this specication, and to the letters of reference marked thereon.

The nature of my invention consistsinsuspending the cylinders of oscillating engines upon gimbal-rings, or their equivalents, so

cylindertrunnions and the cranklshaft of theengine is not essential to the easy working of the engine. Another important'advantage is realized 1n the suspending ofthe cylinder by a gi1nbal-ring-namely, .that aV space is permitted near the cylinder, at and'near its axis of-oscillation, for the attachment of rods to operate the'valve-moving mechanism, so that the operation of `the' valves isnot materially affected by the motion of the cylinder 5' and my invention also embraces somel im.` proved mechanism for operating the induction of which Ieconomize power in the'vvorking of the valves and am enabled to employ a varia= ble cutoff', controlled by the regulator or govern'or with less complex machinery than Vhas heretofore been successfully employed.

Figure'l represents a plant-of the engine. Fig. 2 represents afront elevationof .the cn gine. Fig. 3 representsa 'side elevation of the engine. Fig. 4 represents the rock-shaft Fig. 5 represents the calnofthe steam-valve gear on an enlarged scale. Fig. 6 represents in detail the parts of the cam shown in Fig.' 5. Fig. 7 represents the governor. Fig. 8 exhibits anoscillating cylinder suspended by a modification of this invention bya univer The same letters of reference re saine parts in the several figures.

A ist'he cylinder of the engine, which may be of any ofthe known forms ofl construction,

late to the haust valves. Y

B is the piston-rod. C is the crank. D is l the shaft. `E is the ylwhcel and F is the frame of the'engine.

. G and H are the trunnions of thecylinder'A..

which, instead of'resting upon bearings rig# idly fixed to the' frameof the engine, are sup ported in bearings I and K, formed by the ring L, which'ring L is sustained by the trunnions M and N,resting in the bearings O and P in the frame F.- I t is obvious 'that a cylinder thus supported is free to vibrate in'every direction, and as a consequence no straining ofparts and undue friction will resultiwhen g by Wear or accident the shaft D ceases to be perfectly parallel with the axis of the trunnions M and N. vThe tr'unnions M, N, G, and H may be made tubular, and also the gimbal-ring L, so as to form channels or passages for the couductingof steam to and from the cylinder, as shown insections by the dotted lines in Fig. l. The exhaust-valves are Worked by a lever, Q, whose fulcrum is'upon the cylinder, and the center of the pin S, through which it receives motion, describes an arc passing through the axial line of the trunnions G and H .j-j Motion is imparted to the lever Q by the flink: T, connecting it with the arm Il of the rockshaft V,'which describes nearly or quitesemicircular arcs. 1 The effect of this motion of the rock-shaft Vis to make the motion oi the parts moved by thelink T very rapid inthe middleof 4 the stroke and extremely slow asthey approach the ends of the stroke, thus effecting a rapid` and full opening. of the exhaust-valves with but littleniotion when they are opened or wh en they are closed,and also a very rapid closing movement. There are two other arms, YV and fVV'-, .to the rock-shaft V, through which it reL 'ceives motion fromzthe, short links IX and Y, which are of equal central lengths,y and are attached'by pins in the rod z,- whose central distancesfrom each other is equalto the central Vlength of one of the shortiinks X or Y. The vrod. z is operated by an eccentric'or crank pin, c', rotated by the mainshaftof the engine,l as shown in Fig?,orimaybemoved by a cam on thefshaft D, but-I"l conside eccentric preferable.l The combined action of the eccentric a, rod z, links X and Y, and arms W and W is to impart, when the shaftD rotates, a vibratory Fmotion to the rock-shaft V, which is very slow A the sameend.

` pawl g engages in the ratchetjlf as it approaches the extremes of itsvibratlons,

but is rapidly accelerated near the middle of the vibration. vThis, variablel velocity of the rock-shaft V, combined with .the effect of the semi-rotary motion of the arm U, moving the link T, which is connected either to a stem rof' the exhaust-valves or a lever operating the exhaust-valves, causes 'the motion of the er1-,5

haast-valves to be very slight when open and whenclosed, thus avoiding the friction when subjected to pressure, which is generally greatest during the travel ofthe piston, as is Well understoodv by steam-en gin eers, and least at or the strokes of the piston, 1

The` rapid velocity of the valve affords a `quick and' free escape, for' theI exhaust-steam from the cylinders Without so great an enlarge- A ment of theeXhaust-ports and valve or valves as would otherwise be requisite to accomplish The same motion of the rockshai't V may be obtained by substituting for the arms W and W and linksX and Y a sector and chains, as shown in Fig. 9, or a cogged segment and a rack, as shown in Fig l0; but I prefer to use the'links X and Y andthe arms W and W.

-I am aware that a devicehas been madev for causing the exhaust-valves of engines to have but little motion Whenclosed and' rapid movement when opening and closingl by the use of a wristplate, with the studs so located that valves 'connected therewith have the most rapid movement when openingand clos ingr; but this ldoesnotproduc the slow motion or rest when the valves are 4opened which ,is

Vattained vby the use of the device I have hereinbefore described, and, as a consequence, both of the exhaustvalves cannot be operated from the same link and .stud upon the wristplate, so thatv two valves having 'a larger extent of motion when opened are requisite on account of the velocity of the motion of them not being the same at the same time; Abut in my device one valve or two valves moved togethercan be used, because of the motion of the opened valve being the same as that of the.

closed valve, and forthis reason a greater simplicity of parts in the valves is thus admissible Without detriment tothe Workin g of the engine by` resistance to the free escape ofthe steam, making a back pressure upon the piston.

The steam orinduction valves are'worked by the compoundcam b,which consists of a'cam, o, secured upon the shaft D, and which has a hub,d, upon which lits the came, so 'as' to be susceptible of rotation. Against the cam c lis placed a ratchet-wheel, f, fastened to the hubvl d, on which it is fitted. A pawhg, is Xed on the side of the -cam ,so as When the pawl g is engaged in 'gthe teeth of the ratchet f the cam e rotates with the cam c in whatever relative. position it may be in to c at the timethe The pawl g is of su'cha form that when disengaged from j the ratchet j' it projects beyond the cam e at the part marked Ji, 'in 4which position it is rernear the commencement' and termination of tained bythe spring h, but when pressure. isA -applied by the rollers k or 7c on the levers I and l', which operatethc steam'valves, the pawl g becomes' engaged in the ratchet f with the eifect hereinbefore stated.

The opening -movementof the steam-valves takes place when the rollers 'it and k descend from thc more prominent part m ot' the cam c on the inclined part n to the smaller part, and remain vopen-until the part ofthe cam e moves the rollers to their former position, and therel by close the valves. It is.' obvious upon inspecvtion that the duration of opening ofthe steamvalves is varied by the changes that-are made inthe relative position of the cam. cito the cam c. `The cam c is changed in position'by the link p, attached to 'c by the pin q, and at the other extremity to the governor or regu'- lator-arm r. The governor consists of two Weights or pendulums, s and s, fastenedfupon y the levers r and r', which are hung upointhe bearingst and t', fixed diametrically opposite to each other aty equal distances from the center of the shaft D upon `the ily-Wheel E; lor they may' bepl'aced on a wheel made especiall'y for them. The two pendulums s and s are made independent of gravitation by being connected by the rod tewhich'is attached at Q one end to the pendulunis and at the other to .the lever r at .the extremity opposite to that bearing s. The pendulums thus balance eachother, and they are forced iny toward the' center ofthe shaftby thespring v, connected. to the pendulums by means of the link w;

`The operation of this governor or regulator' is as follows: When the ily-wheel rotates,-

the pendulums sand s describe larger circles 11n proportionas their velocity and consequent centrifugal force exceeds the elastic force of the spring fr until'an equilihriumis main-` tained vbetween the centrifugal force ofthe pendulumsv and the elasticity 'of the spring v, and when the-velocity4 of the wheel E diminishes the pendulums recede again toward the shaft by reason ofthe forceof the spring y ;V, the position of the pendulums and the levers'r and r whichthey are fastened upon is therefore determined by the velocity of rotationof 'the engine, and the came being con= nected bythe link q to the lever r, the lpoint of closing of the induction or steam valves-is thus determined. The-resistance. of the induction-valves and. their intermediate gear to receive motion from the camels prevented 'from reacting npoirthe governor by means of f the paw] gfan'd ratchet f in the manner already explaned. The same result might be attained by using a friction-clutch to holdthe cam at intervalsv When-it i's closing the valve.

v lnall other respects thanthose in which Il have already particularized, this steam-en gine is like those in common use. l

I am aware that engines have been made in which a cam or eccentric used'A for working the lsteam-valves has been varied and controlled in position by a centrifugal governor orregulatonj This I theretbredistinctly dis-` claim. I am also aware thata device has been made and patented for operating the valves of steam-engines by means of studs or pins upon a Wrist-plate, which pins operate the valves, so' that when open they have a large extent of motion and when shut have a small extent of motion in the valve at each end of the cylinder, being operated by a separatev connecting-rod or link moved with a different velocity from the valve at the opposite end of the cylinder, as is set forth in the reissue patent of George ll. Corliss, of May 13,1851. This I distinctly disclaim; but in the mechanism which 1I have described and drawn I impart to both exhaustva-lves one motion, and this motion is different from that produced by the device patented by said Corliss in thisilnportani particular-Hamel y, that when opened at one and closed at the other end of the cylinder the exhaust valve or valves have little or no'motion, and instead ot' rotating but nearly a quarter-circle my ioeclcshaft arm describes nearly seinicircles, and the angular velocity ofthe said vrock-arm is greatly augmented during the middle of its vibration by means of the peculiar arrangement of arms and links through which the said rook-shaftgreceives motion from the eccentric, and by reason of the great cclerity of motion thus obtained and imparted to the valve when vin midtravel I am enabled to use a form of exhaustvalve which during the instant nfits Ygreatestmotion. is open to bothv ends of the cylinder at once without experiencing any practical disadvantage in this adjustment ofthe valve 5 but What I do claim as my invention, and desire to` secure as such by Letters Patent, is-

1. Closing the induction-valves by a positive movement of a 'cam,;.which, while it is ad- 'motion thereto, substantially as hercinbefore set forth and described, for operating the valves of steam or pneumatic engines.

4. Suspending the oscillating cylinder upon a universal joint, substantially as set forth and described. l

y 5. Combining the centrifugal regulator with theiiy-wheel in the manner set forth and described.

s. LLOYD WIEGAND.

Witnesses :v

DENNIS, MEAD, JOHN WHITE.

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