USRE10707E - William saxon abnold - Google Patents

Description

W. S. ARNOLD.

STEAM ENGINE.

Ri-ssued Apr. 6, 1886.

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UNITED STATES PATENT OFFICE.

VILLIAM SAXON ARNOLD,l OF OHATHAM, ONTARIO, CANADA.

STEAM-ENGINE.

JPECIFICATION forming part of Reissued Letters Patent No. 10,707, dated April 6, 1886,

Original No. 310,489, dated January Il, 1885.

T @ZZ whom it may concern:

Beit known that I, WILLIAM SAXON AR- NOLD, a citizen of Canada, residing at Chatham, in the county ofKent and Province of Ontario, Ganada, have invented certain new and useful Improvements in Steam-Engines, of' which the A following is a description.

This invention relates to improvements in steam-engines in which steam is used eXpansively, and the crank is used as a medium for converting the reciprocating motion ofthe piston into the rotary motion of the crankshaft.

In engines using steam expansively by cutting off early in their stroke, the pressure is greatly reduced in the cylinder soon after cutting olf and before the crank is in the best position for Work; and the objects of my improvements are, first, to apply the power which is transmitted t-hrough the piston to the crank when said crank is in a more advantageous position to transmit power than with the present practice; second, I avoid compression on exhaust side of cylinder, and thereby prevent accidents from the accumulation of Water. I attain these objects by the mechanism illustrated in the accompanying drawings, in which- Figure l 'is a longitudinal section 'of a cylinder, steam-chest, and pistons. Fig. 2 is a top view of cylinder, steam-chest, side bars, cross-head, and piston-rods as they appear after the removal of steam-chest cover and valve. Fig. 3 is a plan et' the'entire engine.

Fig. 4 is an enlarged scale side elevation of the cam motion. Fig. 5 isan enlarged elevation of the slotted rocking lever with its sliding block, Wrist-pins, and connecting-rod. Y

Similar letters referto similar parts throughout the several views.

Cylinder A, With the steam-chest M, steamports N, exhaust-ports O, and exhaust-pipe P constitute the cylinder properoi' the engine. The cylinder is provided with three pistons, the center one being the main piston B, and is connected to the main piston-rod E, which transmits power to the crank with the usual connections. The movable piston-.heads C and D are. externally connected to each other by means of the end piston-rods, F F F, crossheads G G, and side bars, H H. The side bars, H H, are provided with Wrist-pins I I, to which connecting-rods m 'm are attached, that have a reciprocating motion adapted to the move toward the cylinder.

Application for reissue filed December-23, 1885. Serial No. 186,571.

time and travel of the piston-heads() D. The slide-valve L controls the admission of steam only, and through its valve rod K is operated by any suitable system of expansion gear. The exhaust-ports O O are so situated in the bottom of the cylinder that the piston-heads C D in their travel control the exit of steam. In the center of the piston-head C is an ordinary stuffing-box, U, through which the niain piston-rod E passes. When in operation, the main piston B makes a portion of itsstroke before steam is admitted to the cylinder, the pistonlheads O D having simultaneously traveled the same distance and in the same direction, then stop, and are firmly heldin place. This position is shown in the drawings, Fig. 1, the dotted lines designating the reverse position of main piston and piston-heads. The eX- baust-port O being uncovered by piston-head D and steam then admitted bythe steam-valve L, the main piston B continues the remainder of' its stroke.

The piston-heads C D are hcld in position and operated as follows: On the main crankshaft a is secured the disk b, on which is asegmental projection, c. Against the face of the disk b, and free to slide across the diameter ot' shaft a, is the plate d, which is provided with two segmental projections, ec". To the plate d is attached one end of the rod g, the other end connecting with the pin h. This pin lz projects from the side of the upper end of a slotted rocking lever, i, the lower end of the rocking lever being pivoted from the bedplate of engine by the pivot u. Across the end ofthe engine bed-plate farthest from the shaft c is jourualcd the small crank-shaft k, said crank-shalt being provided at each end with cranks Z Z and Wrist-pins op. From pins o p are connecting-rods m m, which connect Vwith Wrist-pins l I on the side bars, H I-I. The wrist pin p is extended through the sliding block j, the said block being free to slide in the slot of the rocking lever i. When the main piston B is at that end of the cylinder nearest the main shaft, the projectioncon disk b comes in contact with the projection e on the plate d, thereby causing the plate d to This motion is transmitted to the rocking lever?) by the connecting-rod g. The 'said lever iwill, therefore, through the medium oi' the sliding block j and extended wrist-pin p,-throw the crankshaft c one-half revolution, and thus (as the wristpins o p and I I are connected by the rods m m) give proper motion to the pistonheads C D. When the end of the projection c on the disk b ceases its contact with the end ofthe projection e on the plated, the outer y circumference of the projection c revolves against the inner circumference of the projection e", and thereby prevents motion in the plate d until the projection c comes in contact with the lcwer'projection, e, on the plate d. At the point where the segmental projection c on the disk b ceases its contact with the end of the projection e on the plate d, the outer circumference of the projection c revolves against the inner circumference of the projection e, and thereby prevents motion in the plate d until the projection c comes in contact with the lower projection, e, on the plate d. At the point where the segmental projection c on the disk b ceases its contact with the end of the projection e the cranks l Z have been thrown to their opposite extremes, and the piston-heads C D have reached the extent of their travel and are held rigid in place, owing to the posit-ion ofthe cranks l l. It is at this point steam is admitted to the cylinder. The return-stroke is performed in a similar manner to the foregoing by the segmental projection c on. the disk b coming in contact with the lower projection, e, on the plate d.

It will be seen that the pistonsD C form in reality movable cylinder-heads, and exercise none of the functions of the working-piston of an engine, which in this case is the piston B. Therefore my invention has no reference to such engines having a plurality of pistons. The function of the piston cylinder-heads D C is to take up part of the steam-space on the admission side before steam is admitted, so as to apply the whole power of the steam while the working-piston is in an advantageous po sition to transmit it.

I am aware that prior to my invention steam-engines have been made with more than one piston and with separate steam and exhaust ports, and l therefore do not claim such' a combination, broadly.

What I claim as my invention is 1. In a steamengine, a cylinder having independent steam and exhaust ports and a steam'space shorter than the strokeof the piston, combined with two movable piston-heads reciprocatingly actuated vso as to'prevent the formation of a steam-space on the steam side of the piston during the initial portion of the stroke, and to alternately close and open each exhaust-port, substantially as described.

2. In a steam-engine having separate steam and exhaust ports, the combination of the cy1- inder,movable piston cylinder-heads, a sliding frame by which these piston cylinder-heads are carried, and suitable connections with the crankshaft for reciprocating said sliding frame tocause said piston-heads to alternatelyr close and open each exhaust-port, substantially as described.

` who? 3. In a steam-engine having a cylinder provided with independent steam and exhaust ports, and the steamspace of which is shorter than 'the stroke of the piston, and is formed between movable piston-heads, a sliding frame to which said piston-heads are secured, and by means of which they are moved at the beginning of each stroke to translate the steamspace of the cylinder the necessary distance to accommodate it to the stroke of the piston and to alternately close and open each exhaust-port, substantially as specified.

74. In an engine having independent steam and exhaust ports, substantially as described, the combination of the movable piston-heads D C, the, sliding frame to which they are secured, of suitable connection with the engine for reciprocating said sliding frame to cause said pistonheads to alternately close and open each exhaust-port, and of a crank-motion in said connection which stops on its centers so as to lock the sliding frame, all substantially as described.

5. In an engine substantially as described, the combination of the movable piston-heads D C, the reciprocating sliding frame by which they are carried, the wrists I, the rock-shaft k, operated by the engine, the cranksl on said rockshaft, and the links m, all substantially as described.

6. The combination, in a steam-engine, with the movable piston-heads C D, and the rods H and cross-heads G, connecting the same, of the crankshaft a., disk b, having projection c, the plate d, with projections e e", the crank-shaft 7c, and connection between the cranks ak, subv stantially as and for the purpose specified.

7. rllhe combination', in a steam-engine, of the side bars, H H, provided with wrist-pins I I, the crossheads G G, carried by said side bars, the piston-rods F F F, secured to crossheads G- G, the piston heads C D, secured to pistonrods F F F, all having'an intermitting reciprocating motion derived from and operated by the mechanism consisting of the disk b, with its projection c, said disk being secured to the shaft c, the plate d, with its projections e e, the rod g, which connects the plate d to the upper end of the slotted rocking lever i, the sliding blocklj, the wrist-pins o p, the cranks l Z, the crank-shaft'k, and the connecting-rods m m, which connect the wrist-pins o p with the Wrist-pins I I on the side bars, H

H, all substantially as described, and for the purposes specified.

48. In asteamengine cylinder, the combina` tion of the movable piston-heads G D with the steam-ports N N, a Valve, M, a piston, B, moving independently of the pistonheads G D, and the independent exhaust-ports O O,

substantially as shown, and for the purposes specified. l

. WILLIAM SAXON ARNOLD.

Vitnesses: j

, H. SJSPRAGUE,

CHARLES J. HUNT.

I OO

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