US222803A - Improvement in operating-cocks for fluid-pressure brakes - Google Patents

Description

G. WES'TINGHOUSE, Jr. r Operating Cook forl Fluid-Pressure Brakes.

No. 222,803. Patented Dec. 23,1879.

. m mm .m nYR parts- UNITED STATES N PATENT Ormea GEORGE WESTINGHOUSE, JR., OF PITTSBURG, PENNSYLVANIA.

IMPROVEMENT IN OPERATING-COCKS FR FLUID-PRESSURE BRAKES.

`Specification forming part of Letters Patent N0.`V222,S03,"dated December 23, 1879; application filed Y November 10, 1879.

To all whom it may concern.'

Be it known that I, GEORGE W Es'rnvcr HOUSE, Jr., of Pittsburg, county of Allegheny, State of Pennsylvania, have invented or discovered a new and useful Improvementin Operating-(locks for Fluid-Pressure Brakes; and I do hereby declare the following to be a full, clear, concise, and exact description of the invention, reference being had to the accompanying drawings, making a part of this specitication, in which -like letters indicating like Figures l and Zare sectional views,`in dit'- ferent planes, of a cock in diit'erent positions of adjustment, illustrative ot' the present invention and its manner of operation.

The device shown in the drawings, taken as a wholeVI term a cock, partly for convenience, and partly because it is intended, `in a steam-pressure brake, to take the place and perform the functions ot' the operati n g-cock in a compressed-air brake, which functions are, in the present case, to admit the Huid-pressure to the brake-pipes and cylinders fast or slow, as may be desired, to cut ott automatically or stop such admission of duid-pressure, to hold or retain automatically such pressure with little or no increase or diminution,'and also to permit the escape of the huid-pressure previously admitted or charged into the brakecylinders; and it is important, for convenience in use, that' all these functions be performed by movements ot' a single stem, handle, lever, oncrank, so that, so far as the working ot' the brake is concerned, the engineer need give his attention to but a single device; and itis also of some practical importance, in connection with the use of steam, that all moving parts having an outside connection be packed or made permanently steam-tight, or nearly so, which, with the ordinary rotating cock, plug, or key, it is somewhat difficult to do.

In the drawings, A represents a case or shell having ears A, or equivalent means, by which to make attachment with any suitable support. In the lower end of the case is a chamber, a, having a ported` diaphragm, a', such as is common in the valve-chambers of globe-valves, but having its valve-seat on the under side, as shown. From this chamber a, below the diaphragm af, connection is made by port B and pipe Bwith the boiler, and from the chamber above the diaphragm a port, B2, and pipe Blead to and through the usual brake-pipe to the brake-cylinders.

The upper part ot' the case Ais cored or chambered out7 substantially as shown, sc asy ner as to give an annular port or chamber, D ,L

extending around it, inside the shell, and with a series of ports, c, leading thereto from an i annular chamber, c', made inside the bushing,

the chamber D opening on one side into-a pipe, D2, which leads to the external atmosphere.

The bushing is made with two valve-seats, c2 c3, one above and one below the annular chamber c', and on these seats, with a short range or vertical motion therefrom, is avalve, D4, having corresponding seating-faces c f. This valve is kept to its seats partly by its own gravity and partly bya preponderance ot fluidpressure on its upper end, (that end being the larger,) and is raised from its seats by means presently to be described.

The upper end ofthe shell A is closed, or rather lengthened, by the extension A2, the lower end of which is bored out, so as to act as a guide to the piston-head I), the enlarged part P of the piston-stem playing therein, and a screw-thread of steep pitch being provided in its upper end,

A hollow exteriorly-threaded screwplug, S, is worked inside the extension A2 by means of a crank-arm, S. A shoulder or collar, s, is made in the inside ofthe upper end of the cavity of the screw-plug S, so tha-t the stem p of the piston-head P passing through may be secured by a pin, si', which extends through the stem, and the ends of which swivel on top of the collar s.

A spring, s2, is arranged between the collar s and the base end ot' the enlargement P', so as to operate with a pushing force in thedirection of its length.

lt will thus be seen that the screw-plug S may be rotated without causing the rotation` the train is in running condition.

2 :masas of the piston-head P 5 but the stem p extends below the piston-head, as shown at p', and passes through the valve D, and for a little distance below the valve, and in fact far enough to abutagainst the stem e of the valve c, which latter has a seat in the port of the diaphragm a. A pin, a, passes through the stem p' a short distance below the lower end of the valve D4, and a collar or washer, n', is arranged on the stem above the pin.

The valve c is held up to its seat partly by Huid-pressure acting beneath it and partly by a spring, e2, and it is guided in its motion by its stems c c3. rPhe stems e an'd p' are grooved Vin the direction of their length, or made wingshaped in horizontal cross-section, or otherwise so shaped that when the valve e is unseated fluid-pressure may pass freely from a to a2 beneath the piston-head P, as well as to the brake-cylinders. The ends of the device are closed by screw-caps K K 5 but in the npper screw-cap, K, I make a chamber, 7c, of such size and length that the upper end of the stem p. with its fastening s', may have ashort range of motion therein in a vertical direction, the maximum length of such motion being, by preference, equal, or nearly equal, to the maximum length of motion of the valve e. l

In Fig. 2 I have shown the relative position of the valves when the brakes are ot'f and The valves then are all seated. Ordinarily the screwplug S will be turned up a little from what is there shown, since the spring s2, as here represented, is under partial compression, as will presently be explained.

When, now, the engineer desires to apply the brakes, he operates the crank S so as to screw the plug S downwardly much or little, according as he may desire to apply the brakes with much or little force. motion of thev plug S is communicated through the spring s2 to the piston P, and through its stem p to the stem c of the valve e, so as to unseat the latter, as shown in Fig. l. Fluidpressure from the boiler then passes from B to B2 and on to the brake-cylinders, and is there operative in applying the brakes in the usual way. The steam-pressure also passes freely along the stems from a to a? below the piston P, so that the valve D4 will be held to its seats, not only by its own weight, but also by a preponderance or excess of pressure on its upper and larger end. rIhus the escape is kept closed. rlhe engineer in this way opens the valve e, so as to admit much or little tiuidpressure, as hc may desire, and he regulates the amount of such pressure by the amount ot' port-opening which he makes in shifting the valve c off its seat, or, in other words, by the length of motion imparted to the valve e. Assuming it to be shifted from -its seat in Fig. l a distance which will give one-halt' the maximum'port-opening, the operation will be as above described, but with this additional element, viz the steam passing freely into the chamber a2 below the piston-head P will act rlhis downward with the same pressure there as in the brakecylinders. As soon as the desired or predetermined amount of pressure has thus passed through the port-opening ofthe unseated valve e, any excess of such pressure acting on the under side of the piston-head P will compress the spring s2, and thereby raise P, and with it the stem p p', and thereby permit the valve c to be forced to its seat. Also, it will be observed that the spring e2, which is beneath the valve e, co-opcrates in giving this motion to the piston-head P, and the cessation of such force when the valve e comes to its seat and the increased resistance of the spring s2 as it is compressed result in the stoppage of the upward motion of the piston-head yP as soon as the valve c is seated. Hence the forces so acting will be insufficient to carry the pistonstem pp high enough to unseat the escapevalve D4. The position ot' the devices will then be that shown in Fig. 2. The brakes will then be held on without increase or diminution ofthe fluid-pressure except by leakage or condensation, and as soon as this becomes appreciable the Ydiminution of the pressure under theV piston-head P will permit the resiliency ot' the spring s2 to become operative in automatically opening the valve e to such extent as to supply such loss; or if the engineer desires a little additional brake-power,

- he turns the screw-plug S a little farther down,

so as to give an additional opening to theport ofthe valve e and increase the fluid-pressure necessary to recompress the spring s2 and reseat the valve e; and such increase of power will be operative as brake-power before it again acts to raise the }')isto1'1-head I and stem p', and thereby permit the valve e again to resulne its seat. In this way the supply is automatically cut o and the effective Huid-pressure operative in braking is retained, and such eut-oft' function is performed as soon as the desired or predetermined amount of iuidpressure required for braking purposes has been attained; and the amount of such force may be augmented at any time without danger of opening the exhaust or discharge valve.

When the engineer desires to release the brake he screws the plug S up or outand brings the washer a against the lower end ofthe valve D4, and thereby lifts the valve clear of its seats. All the uidpressure (in excess ot' atmospheric pressure) which has passed the valve e has then a free escape into the external atmosphere,so that the brakes will be ob", and in order the better to facilitate the escape of the steam from the chamber a2, I provide a series of ports, t', leading from the inside of the valve D* to its outside, but above the washer a. rIhe entire braking-power may thus be allowed to escape, or only a part, as may be preferred. Screwing the plug S down again will again result in the closing of all the valves. But for the purpose of partially releasing the brakes, or lessening the effective brake-power, the valve D4 may be sli ght-ly raised, and, as soon as the pressure is 222,503 t l Y a sufficiently reduced, be reseated inthe manner described; but the same result may also be secured (say when the devices are in the position shown in Fig. 2 and the brakes are on) by slight-ly slackening up or unscrewing the plug S, so that the piston-head P, being held down by a less degree of spring-pressure, may be raised slightly by excess of fluid-pressure below, and thereby slightly raise the valve D4. Then, as soon as the pressure has been reduced below that exerted by the spring, the latter will force the piston-head P down `and cause the valve D4 to resume its seat.

As some steam will be likely to leak past the packing of the piston-head P, I provide for carrying it off by a pipe, I).

It will now be seen that I provide for operating both the supply and t-he exhaust valves by a single stern, that only one can be opened at once, that either may be opened separately, (much or little,) and that both may be closed simultaneously and automatically, and kept closed whether the brakes are on or off.

Any suitable index-marks or pressure-gage may be employed, it' so desired, to guide the engineer in giving to the crank-arm the proper length of motion or admitting the proper pressure with reference to securing the proper charging of the brake-power into the brakecylinders 5 and while the device described is particularly designed for use as an operatingcock for steam-brakes, it may, with like utility and in like manner, be used for like functions in other huid-pressure brakes. The usual drain devices may be supplied.

i It should be added that the elasticityor compressibility of the spring s2 should, either in its manufacture or adjustment, or in bot-h, be such or so regulated that it will work in the manner above describedthat is to say, that it may be relied on to open or unseat the valve e; but when the valve is but slightly open it will be compressed by a comparatively light steampressure, so as to allow the valve to be closed, and as the throw of the valve e is increased an increased amount of steam-pressure will be required to compress it, 4so as to let the valve close. Thus the length of the throw of the valve will automatically regulate the amount of brake-power applied.

Relative terms, such as above, below,7 under, etc., are herein used in their relative sense, so that the inversion of the device .would not be a material change as regards the invention described herein.

Mechanical equivalents also may be substituted for any or all the devices specied-as, for example, a double-ended piston-valve workin g in a cylindrical ported chamber may take the place ofthe valve D, and also other suitable means, such as a plunger, may be employed for giving to the stem p the described motions.

I claim hereinas myinventionl.' The valve e and its ported diaphragm, opened and closed by an endwise-abuttin g ste-1n, p', in combination wwith double-seated valve D4, arranged on such stem, a system of escape-ports leading from between the seats to the external air, and a connection from the stem with such valve, whereby the latter may be unseated after the former valve has been seated, substantially as set forth.

2. As a means for automatically cutting ot't' the fluid-pressure supply `when the desired pressure has been charged into the brakecylinders, a piston-head, I), movable by the operative brake=pressure or any excess thereof, in combination with the charging-valve and a connection from one to the other, substantially as set forth, whereby such movement of the piston-head will result inthe automatic closing of the charging-valve, substantially as set forth.

3. Thccombination of piston-head, charging-` valve, interposed stem,'and escape-valve, substantially as set forth with reference to the opening and closing of the charging-valve, without necessarily opening the escape-valve, substantially as set forth. i

4. The'coipbination of piston-head, charging-valve, interposed stem, escape-valve, and

a single operating'- stem, adapted by independent connections with both valves to shift both by independent successive motions, substantially as set forth.

5. A fluid-pressure brake-charging valve opened by a positive but variable mechanical force acting through an interposed spring, and automatically relieved of the force which opened it by the duid-pressure itself acting to compress such spring, substantially as set forth.

6. An operating cock for fluid-pressure brakes, having, in combination, a spring subject to positive but variable mechanical pressure in one direction, and, by a piston, subject to a variable duid-pressure in the other direction, a supply or charging valve opened by the positive motion imparted to the spring and closed by the action of the fluid-pressure, and a discharging or exhaustvalve held toits seat by duid-pressure whilethe'brakes are on, but raised from its seat only after the chargingport is closed, substantially as set forth.

7. The double-seated exhaust or dischargingvalve D4, playing freely on the stem p' within the necessary range of motion for opening and closing the supply-valve e, whereby, in opening and closing the supply-valve, the discharging-valve retains its seats, in combination with a system of exhaust-ports between the seats, and a ring, collar, r catch, fn', ou

the stem p', arranged to unseat the dischargevalve after the supply-valve is closed, substantially as set forth.

In testimony whereof I have hereunto set my hand. GEGRGE WESTINGHOUSE, JR. Witnesses:

1t. H. Wnrr'rnnsnv, C. L. PARKER.

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