US389643A

US389643A - Air-brake

Info

Publication number: US389643A
Authority: US
Publication date: 1888-09-18
Anticipated expiration: 1905-09-18

Description

(No Model.) 5 Sheets-Shet 1.

T. s. E( DIXON.

AIR BRAKE. l No. 389,643. Patented Sept. 18, 1888.

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(No Model.) 5 sheets-sheet 2.

' T. S. E. DIXON.

AAIR BRAKE.

VP zildzentd SeptQlS, 1888.

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(No Model.) 5 Sheets-Sheet 3.

T. S. E. DIXON.

lAIR BRAKE.

No. 389,643. `Patented sept. 1.8.1888.

'(No Model.) A 5 Sheets-'Sheet 4.

T.`S. Ef DIXON.

AIR BRAKE.

No. 889,648. Patented sept. 18, 1888.

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T. s.. E. DIXON. AIR BRAKE.

No. 889,848. Patented sept. 18, 1888;

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' UNITED STATES PATENT OFFICE.

THERON s. n. DIXON, or HYDE PARK, ILLINOIS.

Al R-BRAKE.

SPECIFICATION forming part of Letters Patent No. 389,643, dated September 18. 1889.

Application filed July 17, 1888. Serial No. 280,150. (No model.) Patented in Belgium August l, H83, No. 61,643.

' citizen of the United States of America. re-

siding at Hyde Park, in the county of Cook and State of Illinois, have inventedfcertain new and useful Improvements in Air-Brakes, (for which l have obtained a patent in Belgium, dated August 1, 1888, and numbered 61,643 of which the following is a specification.

AIn the drawings, wherein similar reference-V parts, Figure lis an axial section ofthe governl ing-valve and its casing; Fig. 2,a cross-section, reduced in size, through line X X of Fig. l; Fig. 3, an axial section showing a modified structure; Fig. 4, a partial section showing another form; Fig. 5, a plan view showing the preferable arrangement of the auxiliary reservoir, brakecyliuder, governing-valve, and train-pipes, with parts broken away to economize space in the drawings; Fig. 6, an axial section ot' the retaining-valve and casing; Fig. 7, an axial section of the combined detlector and plug; Fig. 8, apartial section showing the spring K arranged at the inner end of theV governing-valve; Fig. 9, an axial section showing one mode of applying the spring-stop;

Fig. 10, an axial section of the spring dustshield; Fig. 1l, an axial section of the brakecylin-.ier and the improved brake-piston and its stein; and Fig. 12, a partial plan and section of the two trainlpipes, their controlling valves or cocks on the locomotive, and a portion of the main reservoir.

rIhis invention relates to the so-called automatic77 air-brake system, in which an airpump on the engine and a main air-reser voir 7 ou the engine or tender are combined,

by means of a train-pipe extending throughout the train, with auxiliary air-reservoirs on the several cars, brake-cylinders containing pistons connected tothe brake mechanism,and valve-casings, each containing au air-piston or diaphragm subject to the pressure of the auxiliary-reservoir air at one end and the trainpipe air at the other end, and controlling the movements of a valve which governs the admission of compressed air from 'the auxiliary reservoir tothe brake-cylinder and its subsequent discharge therefrom to the atmosphere,

and in which System the engineer, by charging or venting the train-pipe at the engine, open ates said valve-controlling pistons, so as to canse thesetting and releasing of the brakes on the several cars. As usually constructed and operated, when a small quantity of airis vented from the train-pipe at the engine, said valvecontrolling pistons move outward till they rest against the end of a spring-rod and there stop, in which position they cause the valve to temporarily open the service or grading7 port and set the brakes with a moderate pressure against the car-wheels; but when a large quantity of air is vented from the train-pipe the pistons do not stop at the point where they cause the opening ofthe service-port, but move outward farther, compressing the spring of the spring-rod, and causing the valve to open another port, termed the emergency-port, which vents the whole auxiliary-reservoir pressure into the brake-cylinder and sets the brakes with full force against the wheels.

My invention comprises several improvements, which are capable of separate or conjoint nse, and which are respectively designed to improve the operation and promote the practical efficiency of such system and to remedy practical defects heretofore found to exist in it. Among the most serious of such defects are the following, to wit: First, gradingthat is to say, the setting and holdingof the brakes under a moderate pressure for a considerabletime,and the increasing of such pressure at wiil,while the brakes are set and without releasing them, for the purpose of slowing-up a train or easing it down a gradehas not been able to be satisfactorily accomplished by the engineer through the manipulation o t' his charging or discharging cocks on the locomotive; secondly, the air-reservoirs have b een liable to become exhausted,particu larly on long downgrades,and thereby the whole air-brake system to become inoperative and useless atthe very time when itis most needed; thirdly, the valvelpistons have been liable occasionally to stickimmovably in their casings, and the entire apparatus to be thus rendered uncontrollable; fourthly, when, at the end of a trip, it becomes desirable to exhaust the compressed air from the auxiliary reservoirsm or, as it is technically termed, bleed77 them off-theengineer has not been able toaccomplish it `by his pressurecontrolling cocks 0n ICO the engine, but has been obliged to send men along the train to open special cocks provided for the purpose, and again to close said cocks preparatory to recharging the reservoirs for a 5 new trip, and,iil`thly, the heavy brake-pistons have been liable to gradually wear away at their lower edge and permit the compressed air to leak from the brake-cylinders.

In the following specification, for convenlo ieuce of description, I shall use the term governing-valve77 to indicate the combined air-piston or diaphragm and its associated valve or valves, arranged in the valve-casing under each car, and operating to govern the admission of compressed air into the brakecylinder and its subsequent discharge therefrom, and with reference thereto I shall use the term inner 7 end to signify the end or side subject to the reservoir-pressure, and

zo outer7 end to signify the end or side subject to the train-pipe pressure.

The several improvements by which I accomplish the novel and important results above referred to consist, first, in a governing-valve having a new construction and mode of operation, whereby the engineer is able at will to open the service-port and set thev brakes, and then close it and hold them set for any length of time that he may desire, and ifthe brake-pressure should leak ofi", or he should desire to increase it, to again open said port and supply the pressure desired as often as he may wish and hold it'thus applied without meanwhile allowing the brakes to be released;

secondly, in a supplementary air-pipe extending from the locomotive and communicating with all the auxiliary reservoirs on the train through ports preferably provided with retaining-valves,whereby, through the manipu- 40 lation of a suitable cock or cocks on the engine, the air-pressure iu the several auxiliary reservoirs may be increased or reduced at will ,/,f-f N'1n order to operate or assist in operating the 5o air communication, controlled by the cocks on the engine,will be thereby established from the main reservoir or the air-pump directly to every brake-cylinder along the train, through which the ai r-pressurc upon the brakes may be 5 5 increased or controlled at will so long as said ports remain open; thirdly, in an improved construction of said retaining-valves and an improved combination of them with the supplementary train-pipe and the auxiliary reservoirs,whereby they operate to hold their respective ports normally open for the passage of air in either direction; butin case of the uneoupling of the cars, or the rupture of the supplementary pipe or any of its flexible hoseconnections between the cars, they instantly close their ports and prevent any loss of air from said reservoirs or from the brakecylinders; fourthly, in an improvement connected with the main traiupipe,whereby the Venting of its air for the purposes of an emergencystop77 will be rendered more quickly effective throughout the train; fifthly, in an improved construction of the brake-cylinder and its piston and pistonrod,for the purpose of preventing the leakage of air from said cylinder, and, sixthly, in certain otherimproved devices and combinations, hereinafter described, and more particularly pointed out in the claims hereto appended.

In the drawings, A indicates the well-known train-pipe of the automatic airbrake system, through which the engineer is accustomed to control the movements of the governingvalves, and which I term iu my improved system the main train-pipe.

B is the brake cylinder containing the brakepiston B'.

G is the auxiliary reservoir, and D is the easing or box which incloses the governingvalve apparatus.

The auxiliary rcservoi rs are preferably filled from the main train-pipe, and suitable ports orpassages controlled by the governing-valve permit the compressed air at the proper times to vent from the auxiliary reservoir into the brake-cylinder'to set the brakes and subsequently to exhaust from said cylinder to the open air to release the brakes. The governing-valve, as heretofore generally constructed, consists of a piston, (or diaphragm,) F, connected to and operating a valve, E, which opens and closes said ports, the piston being subject at its outer end to the pressure ofthe air in the main train-pipe and at its inner end to the air-pressure of the auxiliary reservoir, and standing normally at the inner end of its traverse, in which position of the governing-valve a passage, G, that leads from the brake-cylinder is caused to communicate with the open-air port or exhaust G by means of an elongated recess, g, in the side of the valve E, and the brakes are consequently released.

By venting a little air from the main trainpipe at the locomotive the engineer causes the superior pressure then remaining iu the auxiliary reservoir to force the governingvalve outward until, after having put the recess g out of communication with one of the two passages G G', and thus closed the exhaust from the brake-cylinder, it rests against the spring rod or stem L, in which position a service-port or grading-port or passage, e, extending through the valve E, communicates with the passage G, leading to the brake-cylinder. Thereupon the compressed air vents from the auxiliary reservoir through the passages e G into the brake-cylinder to set the brakes, and continues thus to vent until the air-pressure at the inner end of the governing-valve falls below that at the outer end, and thegovcrniug-valve, in consequence thereof, moves inward and closes communication between the passages e G. In order now to hold the brakes thus set for any considerable IlO .ear-,643 A e time, itisof course necessary ythatthe governing-valve should cease to move inward assoon as it shall have cut off communication between the passages@ G-or, in other words, closed the serviceportbecause if it should continue to the inner end of its traverse it would place the passages Gg Gin communication, or, in other words, open the exhaust and immediately release the brakes. The difficulty has been to stop the governing-valve at the proper place, for the reason that a preponderance of air-pressureatils outer end suffcientto initiate itsinward or return movement is ordinarily sufficient to carry it clear back to the inner end of its traverse-l Atlem pts have been made to overcome this4 difficulty by arrangingasupplementary puppet-valve to open and close the passage e through the main valve, giving the actuating-piston aslight play or lost motion with respect to t-he lmain valve and utilizing this independent play of the piston to operate the supplementary valve for the purpose of opening and closing the passage through the main valve, whereby it was expected that the rst sl ight preponderance of airpressure which should occur at the outer end of the piston would be suiiicient to start it back to the eX- tcnt of its lost motion, and thus seat the puppet-valve and stop the further escape of air from the reservoir to the brake-cylinder, but would be insufficient to overcome the friction of the main valve against the wall of the casing, and therefore that, under such conditions, the piston would simply seat the puppet-valve and then stop until, by the admission of greater pressure through the trainpi pe, the engineer should force the piston with both of its connected valves to the inner end of their traverse, and thus release the brakes; but experience has shown that the friction of the main valve and thatof the piston itself against the walls of the casing are uncertain elements, and that a preponderance of airpressnre sufficient to overcometlie latter is quite liable to overcome both and return the governing-valve at once to the brake-releasing position, or-else, if not, is insufficient to hold the puppet-valve properly seated, and hence allows the reservoir-air to continue leaking into the brake-cylinder. This practical difficulty, which has hitherto proved insurmountable in the automatic air-brake system, is entirely overcome by my improvements, wherein l. introduce two new principles or modes of operation, which, for their respective purposes, may be used independently of orin conjunction with each other.

My iirst improvement consists, broadly, in

preferable construction is show-n in Fig. 1, and

(excluding from consideration for the present the spring Kshown in said drawing) is as follows:

F2 is a chamber formed in the main piston ,F and communicating with the air-spaces at the ends of said piston.

F is a piston, (or diaphragm,) which Ishall term the supplementary piston,7 arranged in the chamber F2 so as to have a limited movement or play therein, and connected to the supplementary slide-valve E by a stem, F3, and pin e2. The main valve E is in the form shown by the cross-section, Fig. 2, and is held to its seat by a spring,

The stem Fl of the main piston F is preferably made tubular, slotted, or bifurcated to accommodate the main valve, and guided at its inner end by a cross-head or spider, F5, attached to and sliding with it, and so constructed as not to obstruct the movements of the air. The stern F3 of the supplementary piston extends through the hollow stem F* and passes through the cross-head F5, which also serves to guide it in its -independent movement. A spring, E3, holds the supplementary slide-valve E pressed against the main valve. Thus constructed the supplementary piston moves back and forth with the main piston in the general traverse of thelatter, but has, to the-extent of its limited motion in chamber F2, a limited movement independently ofthe main piston. Both pistons are actuated by the airpressure against their ends; butl the supplementary piston is so packed and its valve E so applied that, together, their independent preliminary movement will he subject to less frictional resistance than will the movement of the main piston and its connected main valve, and therefore they will perform this preliminary movement under the iniinence-of a preponderance of air-pressure so small as to be practically insufficient to move the mai u piston and valve. This result can easily be obtained by packing the main piston, as usual, with the ordinary metal ring-packing,f, and the supplementary piston with leather or other ICO IOS

soft packing, f', o'r by using astronger spring,

E2, to hold the main valve against its seat than is employed in connection with the supplementary valve. The two pistons may also be made diiferential, so that under the same airpressure the one which actuates the supplementary valve will move more readily than the one which actuates the main valve.

The operation is as follows: In the normal position of the governingvalve apparatus (which consists, in this instance, of the two pistonsV and valves) the supplementary Vvalve will hold the passage ethrough the main valve closed; but when the engineer vents a little air from the train-pipe A the preponderance of 'pressure thus caused at the inner end of the governing-valve will first move the-supplenientary pist-on outward independently of the main piston, so as to open the passager,

the open passage e will bc in line with the air-passage G, and the reservoir-air will pass into the brake-cylinder to set the brakes. Now, as soon as the airpressure at the inner end of the governing-valve shall have fallen slightly below that which remains at the outer end, the preponderating pressure at the outer end will move the supplementary piston inward and close the passage c before the difference of air-pressure has become sufficient to start the main piston back, and the governing-valve will thus hold the service or grad ing port closed without opening the brake-release port-a position of things which may be maintained for an indefinite period at the will of the engineer. In this construction it is unnecessary to give either valve any lost motion with respect to its actuating-piston, and a sufficient diiiereutial in favor of the supplementary piston will be established, independently of the difference of friction. by making its exposed and etfectivearea larger than that ot' the main piston, or by so fitting the surfaces ofthe main pistonand the stem L to each other that when in contact they will exclude air from between them au/thus temporarily reduce the effective area of air-pressure against the main piston.

It will be observed that bolli in the old construction, where the supplementary valve is preliminarily moved bythe main piston while the latter is passing through the range of its lost motion with respect to the main valve, and in my new construction,where the supplementary valveis preliminarily moved by a mechanical clement which has a motion independent ofthe main piston, an actual preponderance ol air-pressure at the outer end of the governing-valve is required to close the passage e through the main valve, and is the only torce by which such closing is effected.

My second improvement consists, broadly, in providing another and different source of power to prcliminarily close, or aid in closing, the passage e through the main valve, and in adapting means to practically apply that power for the purpose referred to, to the end that the supplementary valve may be moved to close said passage before any effective preponderance ot' air-pressure is established at the outer end of the governing-valve, for example, while lhe air-pressure isequalized at both ends of said valve, or is even slightlyless at the outer than atthe inner end. In the application ofthis new principle l preferably employ a spring to furnish theadditional power, combining` such spring with the piston which acluatcs the supplementary valve to prclilninarily close the port through the main valve in any suitable way, whereby the outward movement of said piston under the inliuence of the reservoir-air, to open the service-port, will compress the spi-ing and open the passage e, and, when the air-pressure on both sides of the governing-valve becomes substantially equalized, the spring will react and move, or aid in moving, the supplementary valve back to close said passage. The principle is clearly illustrated in Figs. 3 and 8, which represent the old construction of governing valve apparatus,wherein one and the same piston operated both the main valve and the supplementary valve.

K is the spring, arranged in Fig. 3 at the lower end, and in Fig. Sat the upper end, of the piston and piston-stem. In the former case the spring acts against a projecting rod or plunger, 7c, that has a limited movement coincident with or slightly greater than the limited play of the supplementary valve in opening and closing the passage e. In the latter case the spring is arranged between a nut, k", attached tothe upper end ofthe piston-stem, and a guide bar or plate, F5, attached to or rest-ing upoli the upper end of thc main valve. In either case. when the engineer vents air from the train-pipe A t0 open thescrvice-port. the piston F, in the act of moving outward againstthe end ofthe spri iig-stem L,cemprcsses the spring K and opens the passage c. The rcservoir-air now rushes into the brake-cylinder until the air-pressure at the inner end of the governing-valve has sufficiently decreased to allow the spring K to act, whereupon said spring tends to move the piston F back far enough to seat the supplementary val ve Eand close the passage through the main valve; but, there being no prel'ionderancc (or, in any evcnt,no large preponderance) ofair-pressnre at the outer end of the governing-valve,there is no possibility ofthe main valve E moving back to open the brake-release port until the engineer shall have increased the pressure in the train-pipe A for that purpose.

One great advantage in preli minarily closi ng the passage e by a force which is free to act for that purpose before the pressure at the innercnd of tliegoverning-Valve is reduced materially below that at the outer end arises from the fact that with such construction the supplementary valve will close earlier, and a less quantity of reservoir-air may therefore be vented into the brake-cylinder, and hence the brakes can be set with a comparatively light pressure against the car-wheels, which is very desirable for grading purposes where the speed of the train is to be merely slackcned more or less.

I have found that with my improvement the brakes can be applied and held for an indefinite period ata pressure as low as from three to live pounds per square inch of brake-piston surface. Any other arrangement of the spring which will enable it to effect or aid in effecting the preliminary closing movement of the supplementary valve (whether it also operates to open said valve or not) I regard as coming within the limits of this part of my invention.

Taking these two new principles-to wit, that of preliminarily operating the supplementary valve by a member which is capable of moving independently of the piston which operates the main valve and that of employing a force independent of the airpressure to aid IIO in moving'the supplementary valve-my third improvement consists, broadly, in combining them both together in one and the same governing-valve apparatus. This improvement is illustrated in Fig. l, in which the two pistous and valves, constructed and applied substantially as hereinabove described, are combined with a spring, K, which is so arranged that when compressed by the movement of the supplementary valve to open the passage e it will tend by its spring action to force said valve back and close said passage, any arrangement that will produce this result being within the limits of the invention, but the preferable mode of construction being that which is indicated in the drawings; and I may here remark that in all cases, especially when the twopistons are employed, I prefer to make the supplementary valve in the form of a slide-valve, for the reason that it closes the port or passage more tightly than any other form of valve under slight pressures of air and is less liable to be held open by particles of dust. With the two principles thus combined I amable to control the frietional resistance of the supplementary valve, so as to insure its closing before the main valve moves, and I am able t-o close it against or over its porte before the air-pressure at the outer end of the governing-valve apparatus is able under any circumstances to disturb the position of the l main valve; and hence I am able not only to apply my grading pressure from a minimum of four or five pounds up to the maximum of equalization with the auxiliary reservoirs, but to hold it thus applied for any desired length of time with absolute certainty, (ordinary leakage from the brake-cylinders only excepted.) l have found in practice that when two pistons are employed and the spring K is made a little stronger than is necessary for its purposes the two valves will move outward together till the main piston strikes the springstem L, andthe supplemental valve will then move outward independently of the main valve and open the passage e.

By arranging the spring K substantially as indicated in Figs] aud 8-thatis to say,in such manner that when the piston F is seated against the stem L and the spring K is compressed by the superior air-pressure at the inner end of the governing-valve its reacting spring force tends simultaneously to force the main valve outwardand the supplementary valve inwardnot only is an essentially new mode of operation imparted to the structure, but thereby an important practical result is produced-to wit, that the spring both acts to hold the main valve from moving and to move the supplementary valve with relation to it, thus practically insuring the complete and effective closing of the passage e without permitting the main valve to move inward at the same time. With regard to any possible outward movement of the main valve under the action of the spring Kat such time, this is prevented in the arrangement shown in Fig. 1 by the spring L', and in the arrangement shown in Fig. 8 by the spring-stop m (hereinafter described) plus the friction of the main valve against the casing.' The preferable arrangement is that shown in Fig. 1, where the spring K is placed between the two actuating-pistons, so as to react equally, but in opposite directions, against them, and thereby against the valves which they control.

The employment ofa slide-valve for the purposes of the supplementary valve enables me to effect a further and important improvement in the means for charging the auxiliary reservoirs with compressed air from the main trainpipe A. To this end I connect the air chambers or spaces at Ithe opposite ends of the governing-valve by a passage, H, in the wall of the casing D, (shown in dotted lines in Fig. 1,-) provide in the main Valve E a port or passage, c, (also shown in dotted lines,) which will communicate with the inner end of the passage H when the governing-valve is at its normal position, and arrange the supplementary valve so that it will then hold the passage c open to the passage H when the passage e is closed and closed when the passage e is open. When, therefore, the governing-valve is at its normal position, the passage H c is open and the auxiliary reservoirs will fill from the main trainpipe; but the instant that the train-pipe pressure begins to be reduced for the purpose of setting the brakes the supplementary and eX- tremely-sensitive valve E will close the passage c and cut off further communication between the train-pipe and auxiliary reservoirs. In thus guarding the refilling port H c by means of a valve more sensitive than the main valve E, I prevent the possibility of air venting back through the passage H from the auxiliary reservoir to the'train-pipe A when the pressure of the latter is but slightly reduced. It also enables me to ll the reservoirs through a passage in the wall of the casing, and therefore to pack the pistons more satisfactorily, and it dispenses with the necessity of a checkvalve in the refilling-passage. The refillingpassage H is similar to that described in Letters Patent No. 382,031, granted to me May 1, 1888, and shown in Figs. 1, 3, and et of that patent. The passage H c being open when the brakes are off, it then furnishes not only a retillingchannel, as aforesaid, but also an equalizing-passage, through which all the auxiliary reservoirs communicate with the main train-pipe, and thereby with each other, and thus an absolutely uniform air-pressure is assured throughout the system so long as the brakes are off.

As an independent improvement, a springstop may be employed to temporarily hold the main valve E in any desired position with relation to the service-port or the brake-release port, or both. To this end I make a depression or series of depressions, fm,in the surface of the valve E or in its actuating-stem or other connections, preferably giving the ICS IIC

walls of the depressions an inclined or dishing' y form, andI arrangeaspring-stop, 111(01, if pre ferred, a series of them,) so that when the valve reaches the position in which itis desirableto temporarily hold it the springstop will enter one of the depressions and tend to hold the valve from further movement; but it' a sufiiciently-increased force be brought to bear on the valve to move it along its traverse the spring-stop will ride up the inclined wall of the depression and release the valve. The spring-stop may be made and applied in a variety of forms, some of which are shown in the drawings. In Figs. 3, 4, and Sit consists of a rod, m, pressed inward through the wall of the casing D by a spring, m2, arranged in a cap, M, which is screwed air-tight into the outer surface of the casing. In Fig. 9 it consists Ofa spring, m, affixed to the inner Wall of the casing, so that its free extremity, suitably shaped for the purpose, will bear against the side of the valve stem and successively enter thedepressions m therein. The precise form and arrangement are immaterial so long as the spring is adapted to exert at a predetermined point or points in the traverse of the main valve a resistance which is greater than is exerted against its movement at either side of said point or points. and thereby to yieldingly lock or engage with said valve at such.

point in the manner and for the purpose substantially as above indicated. It is obvious that the position of the depressions and stop may be reversed-that is to say, the stop may be carried with the valve and the depressions arranged in the wall of the casing-without departing from the principle of my invention, and that projections may be substituted for the depressions. I arrange one of these depressions where it will act to hold the valve in its normal position, with the brake-release port G open; another where it will hold the valve at the servieeport, and, if desired, another where it will hold the valve between the serviceport and thebrake-release port, with both of said ports closed; but any one or more ofthe locking-depressions above speciiicd may be omitted and only the other or others used, if the constructor prefers. These various positions are respectively illustrated in Figs. 3, 4, and 8. This improvement may be applied with or without the supplementary valve. It acts entirely upon the main valve to hold the latter temporarily at any desired point in its traverse; but whenl the supplementary valve is also used itco-operates with both, holding the one properly in place while the other is moving to a new and predetermined relative position.

As an independent improvement, when the two pistons are employed, I provide one of them with a soft packing-ring.' f2, and the other with a raised ring or bead, f, adapted to seat on the soft packing-ring when the passage e is opened. This device, in connection with the spring K, performs a twofold function, to wit: First, it packs the joint between the two pistons absolutely air-tight when the einer'- gcncy-port is open, thereby preventing the air under the great difference of pressure then existing from leaking through into the comparatively empty trainpipe A; secondly, with regard to the inward movement of the pistons, it tends to establish a small initial differential of air-pressure in favor of the main piston, which, however` instantly disappears when the surfaces f 2 f5 separate from each other. The force of the spring K being preferably adjusted so as to slightly overcome the dif`erential action caused bythe contactof the surfacesfzf, the supplementary piston will commence to move inward before the main piston, and the instant that this initial movement causes the surfaces fl f to separate from each other the opposing differential action disappears and the supplementary valve E shoots back with increased force and closes the port c perfectly air-tight, notwithstanding the fact that at theinstant of closingsaid port the friction upon said valve is somewhat greater than at other times in consequence of the ainpressure over the port. \Vith the two pistons F F arranged as shown in Fig. l, there will normally be a differential action in favor of the piston F so long as the latter is free to move independently of the other, owing to the fact that the chamber F2 communicates freely with the ainspaces at the ends of the governing valve, and also owing to the seating of the main piston on the stem L, and the ring and bead fzf3 will merely vary the amountof this differential with the effect and for the purpose above referred to. An independent and important improvement consists in a supplementary train-pipe,

N, connecting the several auxiliary reservoirs to each other and to the air-pump and main reservoir on the engine and tender by an airpassage which is not under the control of the governing-valves, but normally is open from end to end of the train and filled with air under the same pressure as the air in the auxiliary reservoirs. By means of a cock or co'cks on the locomotive the engineer can fill this pipe from the main reservoir O or the air pump, hold it closed, vent its contents to the atmosphere, or open an equalizingpassagc between it and the main train pipe A. The two train-pipes A N enable him to vary the ainpressure at either or both ends of the governing-valve at will and to simultaneously re duce the pressure on one side and increase it on the other, said valve being held between the two opposing pressures and controlled by varying either.

ln the practical operation of the brake system the supplementary trainpipe N performs several important functions, to wit: First, it preserves an absolute uniformity of air-pressure in all the auxiliary reservoirs along the train at all times, thus insuring the uniform action of all the governing-valves; second,by Venting it to the atmosphere all the auxiliary reservoirs, together with the brake-cylinders and main train-pipe A, can be bled off by IOO IIC

the engineerV without sending men along the train for that purpose; third, its contents bel ing normally in communication with those of the auxiliary reservoirs, it operates to the extent of its capacity as an enlargement of the auxiliary-reservoir capacity; fourth, by -increasing its airpressnre above that of the main train-pipe it can'be employed at any time to force the governing-valves outward and set the brakes with any desired degree of brakepressnre, or to increase their pressure as little or as much as may be desired after they have been preliminari-ly set by the action of either train-pipe, or to restore any pressure lost by leakage from the brakecylinders; fifth, by reducing its air-pressure below that of the main train-pipe, when the brakes have been set,- it will at any time enable the pressure in the main train-pipe to force the governing valves inward and release the brakes; sixth, bysimultaneously increasing the pressure of the one pipe and reducing that of the other the brakes can at any time be set or released far more quickly than by the actionl of either pipe alone; seventh, it enables the engineer to refill his auxiliary reservoirs and keep up their pressnre at all times, and whether the brakes be set or released at the time, for even when they are held set by grading pressure the engineer, by first opening the equalizing-passage between the two train-pipes, can fill both of them and all the auxiliary reservoirs without disturbing the position ofthe governing-valves, and therefore without releasing vthe brakes or affecting their pressure, or he can, without refilling, hofd the brakes thus set for an indefin-ite period; eighth, it enables him to fill or rell the auxiliary reservoirs almost instantaneously, for the reason that its carrying ca pacity is many times greater than that of the necessarily small refilling-passage H c, which leads from the main train-pipe; ninth, it prevents any accidental reduction of the mainreservoir pressure from rendering it impossi ble to release the brakes except by the slow action ofthe air-pump heretofore necessary in such case; tenth, when the emergency-port is open and the brakes therefore set with the full available pressure of the auxiliary reservoirs, a straight-ail passage will be open from the brake-cylinders to the engine by means of the pipe N, through which the brake-pressnre'may be increased to any desired extent by venting air from the main reservoir or the air-pump into the supplementary train pipe; eleventh,

in conjunction with the main train-pipe it increases the effective means for forcing the governing-valves to'move, if any of them should accidentally stick at any part of their traverse. Cocks an are represented in Fig. 12, by which the engineer. may control at will the pressure in the two train-pipes.

The cock n in the main train-pipe is of the form'usually employed for that purpose. The cock n in the supplementary train-pipe is of very similar character; but its discharge-vent n2 is preferably smaller, and it also connects with a small equalizing pipe or passage, a3, extending to the main train-pipe. Its construction is so clearly shown in Fig. 12 that further description is deemed unnecessary.

Even if by the jar of the ruiming train any governing-valve should at any time, when the air-pressure at both of its ends is equahwork outward in its casing until its piston rests against the spring-stein L. no harm will result, for the supplementary valve E will hold -the service-port closed so long as the pressure remainsequal. W'hen the spring stop m is employed to hold the governing valve iu its normal position, however, no such accidental displacement can occur.

In Fig. 4, instead of employing separate passages in the governing-valve to register with the passage G for the purposes of a service-port and an emergency-port, respectively, I make use of a single elongated passage, which I have marked ce' toindicate its double function. This passage may be made larger at or near its inner than at its outer end, in 0rder to allow theair to pass more freely into the brake-cylinder for the purposes of an emergency-stop than for service-stops or grading. This elongated passage is, however, merely the equivalent ofthe two ports-service and emcrgency-permitting of the delivery of air to the brake-cylinder both upon the first outward movement of the piston and after it has made a further movement in overcoming va greater resistance by depressing the spring-stein L.

In connection with the supplementary trainpipe the well-known coupling-hose may be used between the cars to unite its sections, and may be provided with the ordinary retainingvalves, which close automatically when the hose is nncoupled, thereby preventing the depletion of the auxiliary reservoirs at such times; but whether such coupling-valve be used or not, I prefer, also, to employ a new retainiugevalve of my own invention, preferably arranged in a connecting branch, N', between each auxiliary reservoir and the main line of the supplementary train-pipe, and which, while normally open, will close automatically whenever theair-pressure in the supplementary pipe is suddenly reduced a given number of pounds from any cause whatever. The essential characteristics of this new retaining-valve are that it shall open toward the auxiliary reservoiig shall be held normally open by a predetermined spring-pressure,an 1 shall be adapted to close. only when the reduction of air-pressure behind it is so suddenv and decided that the resisting springpressure will be overcome and the valve seated before equalization can take place through the valve-port. rllhe best form in which I have contemplated the application of such valve is that represented in Fig. 6, in which Q is a valve-casing provided with an annular valve-seat covered with leather, rubber, or other soft packing,q. Ris a valve,sliding in the casing Q, and normally pressed away from its IOO seat qby means of a spring, R', which also holds the packing in place,and r is a passage through or around the sides of the valve. When the valve is seated on the packing q, its imperferate bottom closes the pipe or valve-port and acts asa check-valve to prevent the redux otair from the auxiliary reservoir int-o the supplementary train-pipe. \Vhen the air-pressure in the supplementary pipe plus the pressure ofspring It exceeds the backpressure of' the air from the auxiliary reservoir, the valve unseats, the air-prcssure equalizes on both sides of it, and the spring holds it unseated, leaving the branch pipe open for the passage of' air in either direction. lf, now, the air be slowly vented from the supplementary trainpipe at the cock n', the auXiliaiy-reselvoir air will pass the valve and escape to the atmosphere, and said reservoirs mayin this way be entirely emptied. On the other hand, if a coupling-hose should burst or the train part, and the air suddenly discharge in large quantities from the supplementary train pipe, the pressure ofthe auxiliary-rcservoir air will instantly overcome the spring It and close the retainingAvalve, and no escape of air from said reservoirs will take place. I prefer to so proportion the resistance of the spring It and the size of the vent at that even it' the latter be thrown wide open the air will not escape from the pipe fast enough to close the retainingvalves, in which case the retaining-val ves will take care of themselves, andthe engineer need not concern himself about them. I have found that by adj nsting the springs R to act'against the retaining-valves with a force equal to from two to five pounds air pressure per square inch satisfactory results are produced. 'lhis 'forni of' retaining-valve may also, if preferred, be employed at the ends of the pipesections instead of the old form of coupling-valves above referred to-an arrangement shown at N2, Fig. 5.

I-Ieretofore the several governing-valve casings D have communicated with the main train pipe A through branches d, perpendicular to the latter. In the improved forms of air-brake belonging to this class and known as the quick-action brake, one form of which is represented in Fig. 1, the sudden venting of the main train-pipe at the locomotive for the purpose of an emcrgencystop is designed to open a series of local vents through the several governing-valve casings, in order that the train-pipe air may escape through the branches d, as well as l'rom the forward end of the pipe, and the emptying of the pipe be thereby correspondingly hastened. The violent rush of the air through the trainpipe, however, tends to force it past the lateral branches toward the forward end of thc pipe, thereby more or less interfering with the usefulness of the local vents for this purpose aforesaid. To remedy this difficulty, I construct the train-pipe, at the points where the lateral branches connect with it, in such man ner that the air in rushing through it will be diverted or deflected into the lateral branches or directlyinto the valve-casings D, and thereby escape to the atmosphere by the shortest route.

To this end I provide within the main train pipe, and opposite to each lateral branch d, au inclined detleeting-surface, a, preferably a1'- ranged with its apex substantially in line with the center of the lateral brauch or passagexso that the air rushing along through the train` pipe in either direction will be deflected into the mouth of the lateral passage. This may be accomplished in a variety of ways-for example, by curving the main pipe inward toward the lateral branches, as shown in Fig. 3; but I prefer to make the trai n-pipe straight, as shown in Fig. 7, and to arrange within ita sliding block, T, having the inclined surfaces aforesaid, and capable of heilig moved inward and outward by a screw-stem, t, the block, when screwed inward, operating as a valve to close the lateral branch d and leave the train pipcunobstruced, and when screwed outward to open the lateral branch and establish a dedecting device at the opposite side of the main pipe, as shown. In case any brake should ac cidentally become disabled,the brauch d, leading to its valve casing D, can be closed by means of the plug T, as described. A cut-off cock, t', is also arranged in each of the branches N,betweeu the supplementary train-pipe and the auxiliary reservoirs, to enable the air communication on that side of the valve-casing D to be cut off under the same circumstances.

When the engineer wishes to suddenly stop the train, he vents the main train-pipe sufficiently to send the governing-valve outward beyond the point where it opens the serviceport to the point where, having compressed the spring L', connected with stem L, it puts the emergency -port c into communication with the passage G and applies the full reservoirpressure to the brakes. In thus moving outward beyondthe service-port in the quickaction form of brake the main piston Il, or some part which moves therewith, strikes and moves a valve, 1, (sce Fig. 1,) to open a port, 2, by which air is locally vented from the trainpipe under each car through an exhaust-pas sage provided with a valve which closes automatically to cut off' the exhaust from the trainpipe when the pressure in the latter falls bclow that in the brake-cylinder. Heretofore said last-named valve has been constructed in the form of a plug or puppet-valve. In my present construction I enlarge the local exhaust-passage into a chamber, 3, immediately outside of the port 2, and construct said valve in the form of a slide-valve, 4, which covers and uncovers a lateral vent, 5, controlling the slidevalve by a piston, 6, exposed on its rear side to the pressure ofthe brake-cylinder air (through the passage G) and on its front to that of' the air in chamber The slide-valve, in addition to its normal function of cutting off the local exhaust when the trainpipe is sufficiently vented, prevents leakage and dust from interfering with the proper action of the IlO IZO

governing-valve s'tands in the casing D through the exhaust-ports, I provide eae'h'of them'at its outer end with a spring dust-shield, which will close automatically to exclude dust from the port, but will open under the pressure of the escaping air to allow the exhaust to take place. The spring-shield may be applied in a variety of forms; but I prefer to make itin the form of a cap or plate, U, supported upon a stem, u, and 'provided with a spring, u', to `normally hold it closed against the outer end of the discharge-orifice, as shown in Fig. l0.

Fig. 10 is a detached View, in cross-section, of the well-known' cylindrical discharge-orice or exhaust-passage opening outward from the casing D to the atmosphere and inward at G in Fig. 1, and when applied to the trainpipe exhaust opening' inward at 5 in Fig. 1, together With the improvement of the dust cap orshield U, attached to the casing D by the stem u, with a light spring, u', to hold it norfmally closed.

By arranging a bleeding-cools7 v, in each of the train-pipes under each car, employing stop-cocks or retaining-valves at the ends of the sections of pipe N, and placing a stopcoek, fw, at the end of each section of pipe A, an important advantage results/to wit: When the locomotive is to be detached or any part of the train side-tracked, the cocks or valves at the extreme ends of the train-pipes of the detached cars can be preliminarily closed, so as to retain the compressed air in their brake system, and after the cars have then been detached their brakes can be set and released several times successively by merely venting alittle air from one or the other of the two train-pipes, thus saving the trouble of operating the hand-brakes for that purpose. functions of the two cocks o w or UN" may be united Vin a single cock or valve, if preferred.

In brake-cylinders a peculiar difficulty is encountered in the effort to tthe pistons airtight, from the fact that the piston-rods are connected at their outer end to the brake-levers, which, moving in the arc of a circle, give the piston-rods and pistons a slight oscillating movement during their traverse. These pistons, too, are heavy, and their weight "has always been supported entirely upon theiry Oil lowerfedge, which has, therefore, tended to wear away and ultimately to produce a leakageof air'from the cylinder. To remedy this,

I make the piston-rod B2 tubular from its fginn'er nearly to its outer end, and center'it upona stout steel bar, B, which is-fastened v rigidly into the cylinder-head and projects through the piston "B into the larger chamber of the hollow piston-rod, as shown.

The

bearing-ring, b, rounded on its inner side, is inserted into the piston, so as to dt and ride upon the stem or bar B3. The weight of the piston and a part of the piston-rod is thus su pported upon the steel. bar, which centers the moving ports and keeps them from unequal wear without interfering with their necessary oscillation, and Vwhich also,to some extent, reduces the frictional resistance against the piston. The function of the ring is merely to contract the cavity of the piston-rod at or near its inner end, so as to enable the bar B3 to 1 properly guide the piston and yet allow the piston and its rod to slightly oseillate on the bar, and any other method of making this contraction may be substituted.

It will of course be understood that the drawings which illustrate the general principles of the improvements herein described merely represent preferable forms of their ernbodim'ent, which forms may be varied at the,

pleasure of the constructer without departing from the invention, so long as the essential functions and mode of operation ofthe several improvements remain substantially as herein set forth. v

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. In an air-brake system, the combination of the train -pipe, auxiliary reservoir, and

brake-cylinder with a governing-valve con- Alivery of reservoir-air to the brake-cylinder without necessarily moving the main valve, substantially as described.

3. In an'air-brake system, the combination of a train-pipe, auxiliary reservoir,and brakecylinder, and a piston and a main valve operated thereby, with an auxiliary valve to open or close a passage leading through the main valve, for the delivery of air from the auxiliary Areservoir to the brake-cylinder without necessarily moving the latter, and a spring to aid the movement of the auxiliary valve, substantially as described.

4. In an air-brake system, the combination of a train-pipe, auxiliary reservoir,and brakecylinder, and a piston and a main valve actuated thereby, with an auxiliary valve to open or close a passage leading through the main valve, for the delivery of air from the auxiliary reservoir to the brakecylinder without necessarily moving the latter, and a spring whose force is exerted in opposite directions against said valves, substantially as described.

IOO

IIO

` 5. In an air-brake system, the combination of a main piston and a main valve actuated thereby with an auxiliary valve to open or close a passage leading through the main valve, for the delivery of reservoir-air to the brakecylinder without necessarily moving the latter, and a spring and auxiliary piston to move the auxiliary valve, substantially as described.

6. In an air-brake system, the combination ofa main piston and a main valve actuated thereby with an auxiliary piston and an auxiliary valve actuated thereby to open or close a passage leading through the main valve, for the delivery ot' reservoir-air to the brake-cylinder, and a spring whose force is exerted in opposite directions against said valves, substantially as described.

7. In an air-brake system, the combination of a main piston and a main valve actuated thereby with an auxiliary valve actuated by an auxiliary piston arranged in a eliamberin the main piston, and having a limited movement therein for the purpose of moving the auxiliary valve to open or close a passage leading through the main valve, for the delivery of reservoir-air to the brake-cylinder without necessarily lnoving the main valve, substantially as described.

S. In an air-brake system, the combination of a main valve, an auxiliary valve to open or close a passage leading through the main val ve without necessarily moving the latter, a main piston having a tubular stem to operate the main valve, and an auxiliary piston having a stem which extends into or through the stem of the main piston to operate the auxiliary valve, substantially as described.

9. In an air-brake system, the combination of a main piston and a main valve actuated thereby with an auxiliary valve actuated by a spring, and an auxiliary piston to open or close a passage leading through the main valve Without necessarily moving the latter, one of said pistons having a packing-ringjl, and the other a bead, f i, adapted to operate substantially as described.

10. In an ai r-brake system, the combination, with the train-pipe and auxiliary reservoir provided with a connecting-passage for refilling the reservoir, of a piston and main valve provided with a port for controlling said passage, and a sensitive auxiliary valve whose movement opens or closes said port or passage leading through the main valve, substantially as described.

11. In an ai r-brake system, the combination of a piston and a main valve actuated thereby, and having two passages leading through itone a port or passage, e, for the passage of air from the auxiliary reservoir to the brake-cylinder, and the other, c, for the passage of air from the train-pipe to the reservoir-with a sensitive auxiliary valve to open or close said passages without necessarily moving the main valve, substantially as described.

12. In an air-brake system, the combination of a piston and a valve operated thereby with a spring-stop adapted to elt'ect a greater resistance to the movement of said valve at a predetermined point or points in its traverse than at other points in either direction therefrom by its engagement against a resisting stop or depression upon the valve or its connections, substantially as described.

13. In an air-brake system, the combination of a piston and a valve operated thereby with a spring-stop adapted to apply a yielding force in a lateral direction to resist the movement ofthe valve and to vary the resistance at a predetermined point or points in said movement by its engagement againsta resisting stop or depression upon the valve or its connections, substantially as described.

14. In an air-brake system, the combination of a piston and a valve operated thereby with a spring-stop adapted to applya yielding force in a lateral direction to initially resist the movement of the valve from its normal position by its engagement against a resisting stop ordepression upon the valve or its connections, substantially as described.

15. In an air-brake system, the combination of a piston and a valve operated thereby with a spring-stop adapted to apply ayielding force in a lateral direction to initially resist the return of the valve to its normal position by its engagement against a resisting stop or depression upon the valve or its connections, substantially as described.

16. In an air-brake system, the combination of a piston and a valve actuated thereby with the spring stop m and the depression m', adapted to operate substantially as described.

17. In an air-brake system, the combination of a piston and a main valve actuated thereby with an auxiliary valve to open or close a passage leading through the main valve without necessarily moving the latter, and a springstop to resist the return or inward movement of the main valve at a predetermined point or points in its traverse without resisting the independent movement of the auxiliary valve by its engagement against a resisting stop or depression upon the main valve or its connections, substantially as described.

1S. In an air-brake system, the combination 'of a piston and a main valve actuated thereby with an auxiliary valve to open or close a passage leading through the main valve without necessarily moving the latter, and a springstop adapted to apply ayielding force in a lateral direction to resist the return or inward movement of the main valve and to vary such resistance at a predetermined point or points in said movement without resisting the independent movement of the auxiliary valve by its engagement against a resisting stop or depression upon the main valve or its connections, snbstantially as described.

19. In an air-brake system, the combination of a piston, a main valve actuated thereby, and an auxiliary valve to open or close a passage leading through the main valve, with a spring-stop, m, and depressions m', to resist IOO IIO

IIS

the movement of the main valve at a predetermined point or points in its traverse without vresisting the independent movement of the auxiliary valve, substantially as described. 20. In an air-brake system, the combination of a piston and a main valve actuated thereby with an auxiliary valve to open or close apassage through the main valve without necessarily moving the latter, a spring whose force is exerted in opposite directions against said valves, and a stop to temporarily hold the main valve from moving outward under the action of said spring while 'the auxiliary valve is moving inward, substantially as described. 2l. In an air-brake system, the combination of a piston and a main valve actuated thereby with an auxiliary valve to open or close a passage through the main valve without necessarily moving the latter, a spring whose force is exerted in opposite directions against said valves, and a stop to temporarily hold the main valve from moving in either direction while the auxiliary valve is moving inward, substantially as described.

22. In an air-brake system, the combination of the auxiliary reservoirs, the brake-cylinders, the governing-valves,and the main trainpipe A with a supplementary train-pipe, N, which forms a normally-open air-communication between all the auxiliary reservoirs along the train, and which communicates with the main reservoir or air-pump on the locomotive by a passage controlled by a cock, substantially as described.

23. In an airbrake system, the combination of the auxiliary reservoirs, the brake-cylinders, and the governing-valves with a normally-open train-pipe, A, for communicating air-pressure to the outer end of the governingvalve, and a normally-open train-pipe, N, for communicating air-pressure to the inner end of said governing-valves, both of said trainpipes extending to the engine, and being there provided with means by which the'engineer can charge them with compressed air and vary r exhaust their pressure, substantially as described. Y

24. In an air-brake system, the combination of the auxiliary reservoirs, the brake-cylinders, the governing-valves, and the main trainpipe A with an air-pipe leading from the auxiliary reservoirs to the engine and there provided with a cock, by opening which the engineer can bleed 0E the several auxiliary reservoirs, and also provided with retainingvalves, whereby in case of accidental parting of the train the air is retained in the auxiliary reservoirs, substantially as described.

25. In an air-brake system, the combination of the auxiliary reservoirs, the brake-cylinders, and the governing-valves with two trainpipes normally charged with compressed air, and both of them normally in communication with both the auxiliary reservoirs and the governing-valves, and with a connecting-passage controlled by a cock or valve arranged on thev engine, substantially as described.

26. In an air-brake system, the combination of the valve-controlling pistons F F and the valves E E', operating as herein set forth,with the two trainpipes A N, by which said pistons and valves. may be actuated at will by varying the air-pressure at either end of the 28. In an airbrake system, the combination y of an auxiliary reservoir and a supplementary train-pipe, N, with a retaining-valve held normally open by a spring, substantially as described.

29. In an air-brake system, the combination of an auxiliary reservoir, a supplemental train-pipe, N, and a retaining-valve arranged in a'branch, N, between the pipe and the reservoir and held normally open by a spring, substantially as described.

30. In an air-brake system, the combination of the two train-pipes A N, the governingvalve, and the auxiliary reservoir with a retaining-valve connected with the supplementary train-pipe N and held normally open bya spring, vsubstantially as described.

31. In an air-brake system, the combination of the two train-pipes A N, the governingvalve, and the auxiliary reservoir with a retaining-valve arranged at each` end of the pip'e N on each car and operating to automatically close such end when the cars are separated or the connecting-hose broken, and with a cock, w, arranged at each end of the pipe A on each car, and means for bleeding the air from either of said pipes at will when the engine is detached or said terminal cocks and valves closed, substantially as described.

32. In an air-brake system, the combination of the main train-pipeA and its lateral branch ol, leading to the local discharge under the car, with a deflecting-surface, a, arranged in the train-pipe opposite to the end of the lateral passage, substantially as described.

opposing spring force, substantially asidescribed.

35. In an air-brake system, the combination of the ring or contraction b with the piston B', hollow piston-rod B2, and guide-bar-Bi, substantially as described.

36. In an air-brake systen1,tl1e combination IOO IIO

of the valve E with a spring-stop adapted to apply a yielding force against its rear side,for thedonble purpose of holding the valveagainst the ported wall of the easing and also resisting its movement and varying the degree of such resistance at a predetermined point or points in its traverse hy its engagement against a resisting stop or depression upon the valve or its connections, substantially as described.

37. In an airbrake system, the combination of a train-pipe, auxiliary reservoir, and brakeoylinder, und a piston and a main valve operated thereby, with an auxiliary valve to open