US33855A - stevens - Google Patents

Description

UNITED STATES FRANCIS ll.

PATENT OFFICE.

IIMPROVEMENT oN OUT-oFF-VALVE MOTION.

Specification forming part Of Letters Patent No. 33,9355, dated December 3, i861.

To all! 107mm it may concern.-

Be it known that I, FRANCIS Il. STEVENS, of Ieehawkem in the county ot lludson and State of New Jersey, have invented an Improvement on Stevenss CutOiI; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

The nature of my invention consists in certain additions to the valve-motion patented by Robert L. and Francis Il. Stevens on the 25th day of January, A. D. 1841.

The object ot' these additions is, first, to raise the eduction-valves more rapidly than they are commonly raised; secondly, to produce the same effect that the addition to Stevenss cut-ott known as the gags produces. 'lhese objects I produce hy keying or attaching the two eduetion-tappets on the same shaft to which the tappets (or, as they are usually called, the long toes) ot' btcvcnss eut-oft' are attached, and I make these eduction-tappets the same length that the induction-tappets are, and I attach them to the rock-shaft at the same angle, so that if working without any other addition the induction and eduction valves would have the same mo tion, and the eduetion-valvcs, after being raised up as rapidly as the imluetion-valves are raised, would then eut oft the exhaust.- in the same manner that the induction-valves cut oit the steam. Now, to prevent this action of cutting ott' by the eduction-valve and to keep the eduetiol'i-valve from closing until the end or nearly the ond of the stroke, I place a hinge-piece on the top ot the tappets, this hinge-piece being hinged at the end ot the tappets farthest fro m the shaft and raised and lowered at the part nearest the shaft h y small tappets attached to a hollow rock-shaft placed over the main rock-shaft and worked with a vibratory motion by the eccentric that works theeduetion-valves inStcvensseutoti. These small tappets raise the hinge-pieces and keep the eduction-valves open until the end of the stroke. I thus raise the cductionvalves more rapidly than they are commonly raised, and hy as quick a motion as the induction-valves of Stevenss eut-oft' are raised, and still keep them open the requisite time. I produce the second el't'ect above named-that is to say, the eleet produced by the gagsAhy also placing hinge-pieces on the top of the tappets that work the induction-valves, these hinge-pieces being worked by small tappets placed on the aboveanentioned hollow roek-shaft5 but I attach these small tappets to the hollow rockshaft in such manner that their position on the hollow rock-shaft can be altered from a point where no motion is communicated by them to the hinge-pieces to a point where the valve is kept open until the end of the stroke, or to any point intermediate between these two. Thus, when the small tappets are so set that no motion is communicated by them to the hinge-pieces the steam will he eut oil. at the point at which Stevcnss eut-olf is set, and when they are so set that any motion will be communicated by them to the hinge-pieces then the steam will he cut olT at somo longer portion ot the stroke.

I will now proceed to describe my invention with the aid of a reference to drawings.

Figure I is a side elevation ofStcvenss cutott' with my additions attached. Fig. II is a fronty elevation ot' the same. Fig. III is a horizontal view ot' the same. Fig. I is sectioned to the red lines .1 .r of Figs. ll and III. Fig. II is sectioned to the red lines ze' of Figs. I and III. Fig. III is sectioned to the red lines y y of Figs. I and II. Fig. 1V is a horizontal view of the hollow rock-shaft and ot the four small tappets that work the ends ol the tour hinge-pieces. Fig. V is a side view of the long steam-tappcts, the hinge-pieces on the same, the hollow rock-shaft, the small induction-tappets on the hollow roekshal't, and the screw that; elevates and depresses the small tappets on the hollow rock-shaft. Fig. YI is Fig. hut viewed on the reverse side. Fig. VII is a view of the small tappets that work the hinges on the two steam-tappets. Fig. VIII is a horizontal view of the hollow roekshal`t, showing a diilerent method of altering the position of the small tappets that work the hinge-pieces, the hollow roek-shaft being' made all in one piece. Fig. IX is an elevation ot Fig. VIII. Fig. VX is an elevation ot' Fig. VIII, taken on the reverse sideot.`

Fig. IX. Fig. XI is the same as Fig. X, showing the method ol alteringl the small tappets.

a is the index, showing the position ot' the main crank of the engine.

l) is the ccccntrierod that works the rockshaft to which the four long tappets are at@ tached.

c is the eccentric-rod that works thehollow rock-shaft.

(l is the rockshatt to which the four long tappets A, I3, C, and l) are keyed oratiached permanently.

c andf are the imluetion-valve li t'ting-rods.

`i and la are the feet attached lo the indue tiorbvalve lifting-rods- I and m are the feet attached to the eduction-valvc lifting-rods.

n, is the main shaft of the engine.

A and I3 are the two longinductioirtappets of Stevenss cut-off.

C and l) are the two similar tappets that work the eduction-valves.

E and F are the hinge-pieces placed on top of the tappets A and l.

G and H are the hinge-pieces placed on the top of the tappets U and l). Y

I is the hollow rock-shaft that works over the rock-shaft d.

K is the arm attached to the hollow rochshaft and worked by the eccentric-rod C.

L and M are the small tappets that work the hinge-pieces on the inductiou-tappeis A and B.

N and O are the small tappets that work the hinge-pieces on the eduction-tappcts C and D.

l is the frame-pieoe attached to thehollow rock-shaft I for the purpose of holding the screw J.

.I is a screw, on one halt` ol' which a righthanded thread is out and on the other half a left-handed thread is out, and which when turned by the handle R brings together or spreads apart the nuts S and T.

L' and Y are projections attached to the small steam-tappets Il and M, and against: which the nuts S and rl act for the purpose of altering the position of the tappcts I and )l on the hollow' 1'ock-sl1at't.

p p are small screw-bolts that secure the small tappets N and (c) to the hollow rockshaft in the method shown in Figs. VIII, IX, X, and XI.

o is a Screw (shown in Fig. XI) for the purpose of altering the position on the hollow rock-shaft of the small tappet L in the method shown in Figs. VIII, IX, X, and Xl', the lappet M being altered by a similar screw. The small tappet L is drawn showing its position when cutting off full stroke, and is drawn in the red or dotted lines in its position when leaving Stevenss cut-off unaltered.

The operation is as follows: Supposing, in the first place, that the small tappets L, M, N, and O were all removed, then it is evident that the hinge-pieces E, F, (i, and li would ill i lic quietly on the tappets A, l5, C, and D, and that both induction and ed uction valves would be raised and lowered by Stevenss cut-oft and that their motions would he identical, the mach inery t'o r workin g the ed uction-valves being merely a duplication ot` that working the induction-valves- Now when the small tappets N and 0 are attached to the hollow rock-shaft I, as shown in Figs. I, II, III,and IV, the small tappets work the hinge-pieces in the same manner that the tappets of the ordinary exhaustfmotion work the litters. 'lhus the tappets n and o vibrate backward and forward, and alternately raise and lower the hingepieces G and II, and, as thc hinge-piece II lowers the toot y in its scat just the hingepiece (l commences to lift the foot h, itis evident that the eductionvalve attached to the rod q will thus be kept from closing until (or nearly until) the other cduetion-valve attached to the rod h begins to raise, and thus the cduction-valves will be raised by the long tappets C and D as quickly as the inductionvalves are raised by Stevenss cut-oft', and will then he held up to the completion et' the stroke by the small tappcts N and 0. If the small tappets Ti and )I are attached to the hollow rocleshalt I at the saine angle that the small tappcts N and (V) are attached, as shown hy the red or dotted lines in Fig. V, then the induetiolrvalves will have the same motion thc cduetion-valvcs have and will remain open to the end of the stroke; but if they are depressed to the position shown in Fig. Y, and also the dotted lines in Fig. I, then the small tappets IA and M will not work the hollow rock-shaft pieces Eand F,and the induction-valves will be closed at the point at which Stevens`s cut-oit' is set. These small tappets are elevated and depressed, as shown in Fig. Y, by the right and left handed nuts S and T approaching or receding from each other as the screw Q is turned hy the handle R, for the projections U and Y of the tappets Il and M, hy the action ot the weight of these tappets, which are loose on the shaftpress and hear against these nuts. In Fig. Y the small tappets L and M, the projections li and V, and the nuts S and T are shown when thc small tappets are depressed and where the steam is eut ott at the point at which Stevens`s cut-od is set. The red or dotted lines represent the same pieces when these tappets are elevated and where the steam is cut Ct at full stroke. In Fig. 'VIII the small tappets that work the inductionvalve hinge-pieces are attached to the hollow rock-shaft in the same manner thatthose that work the eduction-valves are, and are shifted ou the hollow rock-shaft to the proper angle of elevation or depression by the small screw-bolts p p or by the screw o.

W hat l. claim as my invention is l. Setting the tappets that work the eduction-valves on the same shaft and at or near the saine angle of depression that the tappcts of Stcvenss cutoff are set, so that the eduction-valves eau be lifted at the same speed over the rock-shaft (7 and worked by the ecthat the induction-valves are lifted by Steeentremotiou that Works the @duction-valves venss eut-off. in Stevenss eut-off as commonly constructed.

2. rlhe hinge-pieces E, F, G,a|1d ll, hinged at the ends of the tappets A,B,C,a11d D FRANCIS l. STEVENS'.

and raised and lowered by the small tappets Witnesses:

L, M, N, and O, these small tnppets being CORNELIUS CREEDON,

attached to the hollow rook-shaft I, placed J L'LUS IIORNIG.

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