US235287A

US235287A - perkins

Info

Publication number: US235287A
Authority: US
Publication date: 1880-12-07
Anticipated expiration: 1897-12-07

Description

(No Model.) 3 Sheets-Sheet L. PERKINS 8v W. W. HARRIS.

Valve Geer for Engines.

No. 235.287. Patented Dec. 7,1880.

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N-FETERS. FHOT0L|THDGRAPHER, WASHINGTON, D C.

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N.FETE.RS; PKOTO-LWHOGRAFNER, WASHINGTON. D C.

(No Model.) sheets-Sheet 3.

L. PERKINS 8v W. W. HARRIS. Valve Gear for Engines.

No. 235,287. Patented Dec. 7,1880.

N. PETERS. PHOT0-UTHOGRAPMEIL WASHINGTON. D C4 zo the steam-passage below the valve.

4o be the lower one.

UNITED STATES PATENT EEIcE.

LOFTUS PERKINS AND WILLIAM W. HARRIS, OF SEAFORD STREET, COUNTS OF MIDDLESEX, ENGLAND.

VALVE-GEAR FOR ENGINES.

SPECIFICATION forming part of Letters Patent No. 235,287, dated December 7. 1880.

Application filed October 12, 1880. (No model.) Patented in England January 14, 1880.

5 ford Street, in the county of Middlesex, England, have invented certain new and useful Improvements in Valve-Gear for Engines, (for which we have received Letters Patent in England, N o. 168, dated 14th January, 1880,)

1oof which the following is a specification.

In the specication of a former patent granted to one of us, dated 13th April, 1880, No. 226,416, was described means of opening and closing valves used for controlling the r 5 admission and escape of steam from the cylinders of steam-engines whenever lifting-valves were usedfor this purpose. Each valve was lifted from and lowered onto its seat by means of a rod passed up through a stuflng-box into The rod had a positive upward and downward motion given to it, and moved away from the valve when the valve was resting on its seat. When such valves were used for controlling the ad- 2 5 mission and escape of steam to and from the low-pressure cylinder ot' the engine described in that specification, the space occupied by the four valves and valvepassages requisite for its control was considerable. To allow of lift- 30 ing-valves being used for controlling the ad- 3 5 being too great, we now place the steam and exhaust valves used for controlling the pas sage of steam to and from each end of the cylinder in valve-chambers vertically one above the other. The exhaust-valve is arranged to It is raised and opened by a tube which passes up through the tubular center of the valve-seat. The upper valve, which is the steam-valve, is opened by a rod which passes up through the center of the 45 tube that opensthe exhaust-valve.

5o or rings to cover these openings.

At the top of the valve is a central collar, from which pass radial arms, which serve to hold the collar and rings together, and it i: upon this collar that the lifting tube or rotl acts to raise and open the valve.

The valve-rings are formed with incline( valve-faces at top and bottom, to lit on corre sponding valve-faces at the top and bottom o the openings in the valve-seat. Each soli( ring of the valve is also arched outward, so as when lifted, to give a free passage of steam t( the openings in the valve-seat.

The valve-chambers containing the valve: for controlling the passage of steam to an( from one end of the cylinder we place side by side with the chambers containing the valve: for the other end of the cylinder.

Figure l is a section showing two pairs o: lifting-valves, arranged as above described for admitting steam to and allowing it to es cape from both ends ofthe cylinder of a steam engine. Fig. 2 is a section, taken at righ` angles to the section Fig. l, through the pai] of valves for admitting steam to and allowing it to escape from the lower end of the cylinder These gures show the valves applied to tht low-pressure cylinder of a steam-engine con structed as described in the specification abov( mentioned; but, as before stated, similar valvf apparatus may be used for admitting steam t( and allowing it to escape from the cylinder.l of other engines.

A is the inlet-valve for admitting steam t( the upper end of the cylinder, and B the ex haast-valve for this end. C is the inlet-valv( for the lower end ot' the cylinder, and D the exhaust-valve. These valves are in separate chambers A' B C D'. The inlet-valves A rest on valve-seats Az C2, which stand ou from plates forming the division between the chambers A Bl and C D. The exhaust valves B D rest on valve-seats B2 D2, whicl form part of the division between the cham bers B D and the exhaust passage E, by which the exhaust-steam is conveyed away t( the condenser.

F F are rods for lifting the inlet-valves A C, and Gr Gtubes forliftng the exhaust-valve: B D. Each tube G passes up through a stuft ing-box, H, with a long neck, which stands u1 from the bottom of the exhaust-passageE am rises up above the solid top of the valve-seat: B2 D2.

The valve-rings ot' which each valve is com posed, as above explained, are connected by arms with a central boss or collar, up through which the rods F pass. When the tube is lifted it comes against the bottom of the collar and lifts the valve ott' its seat, and when the tube is lowered the valve comes down with it until it is left resting upon its seat. The rods F pass up through the tubes G, and their upper ends pass into the central boss of the inlet-valves, so that the boss forms a cap to cover over the top of the rod. On the exterior of the boss is a small valve to close down onto a corresponding valve-face formed around the top of the opening in the solid top of the valve-seat, up through which the rod passes, so that the escape of steam through this opening is prevented when thc valve A or C is resting upon its seat. When the rod F is lifted or lowered the valve is raised or allowed to descend onto its seat, as explained.

I is a portion of the low-pressure cylinder of the engine, and J is a portion of a double casing by which the steam-cylinders, passages, and valve-chambers of the engine are all inclosed, as explained in the speciiication before mentioned.

Fig. 3 shows an elevation, partlyin section; Fig. 4, an end view; and Fig. 5, a plan of mechanism for controlling,r the raising and lowering of the rods and tubes, so as to open and close the valves at the times required.

K is a shaft, to which a rocking motion is given from the crank-shaft of the engine. This is best effected by a crank-pin on a crank-arm of the shaft K, (not shown in the drawings,) being embraced by the link of an ordinary link-motion worked by a pair of eccentrics on the crank-shaft. n the shaft K are also two crank-pins, L M. One of these, L, is embraced by a bearing-block, N, which can slide to and fro in a horizontal slot or opening in a frame, 0, while the othercrank-pin, M, is embraced by a block,P,whicb can slide to and fro in a horizontal slotin aframe,R. The crank-pin L oscillates in an are between the radial lines` 1 and 3, while the crank-pin M oscillates between the lines2 and 4. Thus one of the frames 0 R will be raised as the other is lowered. Each frame at its upper part is made fast to the lower end of one tube, G, while the lower part of the same frame has connected to it, by jointed or toggle links S, the lower end ot' the rod F, which passes up through the other tube, G. Thus, as each frame is in turn raised, the exhaust-valve will be opened to permit the escape of steam from one end of the cylinder of the engine, while at the same time the inlet-valve for admitting steam to the opposite end of the cylinder is also opened.

The exhaust-valve will be keptopen throughout the full stroke of the piston of the engine, and if the togglelinks S were kept in a vertical position during the whole time the frame is being raised, steam would also be admitted throughout the stroke; but if, after the completion of one half or third, or other portion of the stroke, the toggle-links are allowed to move into positions inclined to one another, the rod F will no longer be raised or held up by the links, and the valve at the top of this rod will at once close. To be thus able to effect the cut-nii' at any desired part of the stroke we employ an arm or tappet, T, on the rock-shaft K to strike against adjustable stops which are in connection with thecentral joints of the pairs of toggle-links. For this purpose the pins which form the central joint of each set of toggle-links are carried by a tube, U. Adjustable stops V screw the one into one tube and the other into the other tube, one with a righthanded, the other with a left-handed screwthread. Through both stops Vpassesasqnare rod, W, by which they can be turned. This rod also serves as a link to couple together the tubes U ot' the two sets of toggle-links. One end of the rod has for this purpose upon it a nut that bears against the end of one tube, U, while the other end of the rod has upon it a nut, X, which bears against the end of a tube, Y, which fits over the rod W, and which screws into the other tube, U. 0n the tube Y is a handle, Z, by which it can be turned. When turned in one direction it brings the stops V nearer together, and at the same time moves the tubes U farther apart, and when turned in the other direction it moves the stops apart and brings the tubes nearer together. Thus, whenever the iinger or tappet '1 comes against one stop V, and moves it outward, so that the links with which it is connected are made to incline to one another, the other pair of toggle-links are, as indicated by the drawings, always brought into and slightly beyond a vertical position, so that when the slide with which they are connected is in its turn made to rise, the rod F, with which the links are also connected, is raised also. The increase or decrease of the distance between the stops is caused by the tube Y screwing in or ont of the tube U. In this manner the inlet-valves will always commence to open at the same time, but the closing of these valves can be eected at any desired part of the stroke simply b v turning the handle Z.

If the adjustable stops are brought closer together, the iin ger or tappetT will the sooner act upon them and close the inlet-valves at an earlier period of the stroke; or, if the stops are moved apart from one another, they will close these valves at a later period of the stroke.

The time at which the opening of the inletvalves commences can be adjusted by turning the nut X by the handles upon it. By turning this nut the rods F can be slightly raised or lowered with respect to the frames O R, as will be seen, and so the times .at which these rods come against and lift the inlet-valves can be varied to a sufficient extent to allow of slight variations being made in the lead given to the opening of these valves.

We claim- 1. The combination of the steam-cylinder, the inlet-valve A, and the exhaust-valve B IOO IIO

beneath it at one end of the cylinder, the similarly-arranged inlet and exhaust Valves 0 D at the opposite end thereof, the respective valve-chambers A B C D', the tubes for lifting,` the exhaust valves, the rods passing through said tubes and serving to lift the in1et-valves, and mechanism, essentially such as described, for controlling the raising and lowering of the rods and tubes to raise the exhaustyalves, first at one end of the cylinder and then at the other, While alternately openin g the inlet-valves at the opposite ends of the cylinder, in the manner and for the purpose set forth.

2. The combination, with the lifting-rods F and tubes G, of frames O R, each frame attached to the lower end of one tube G aud LOFTUS PERKINS. WILLIAM WALLINGTON HARRIS.

Witnesses:

JOHN DEAN, J. WATT, Both of 17 Gracechurch Street, London.