US761683A - Air-brake. - Google Patents

Description

PATENTED JUNE?, 1904.

J. P. KELLY. AIR BRAKE. APPILIULTIQN FILED Nov. 27, 1903.

No MODEL.

.mrmonms PnERs co'.' Puonxumo.. WASNINGYON, n. c

N0.7e 1,e83. l Patented .rune 7, 1904.

, UNITED STATESy PATENT OFFICE.

JOHN P. KELLY, OE WATERTOWN, NEW YORK, AssIGNOR To NEW YORK AIR BRAKE COMPANY, A CORPORATION or NEW JERsEY.

AIR-BRAKE.

SPECIFICATION forming part of Letters Patent No. 761,683, dated J une '7, 1904. Application iledNovember 27, 1903. Serial No. 182,836. (No model.)

T wwm/ i mU/Z/ @0H/067%! the pressure in the brake-cylinders produced 50 Be it 'known that I, JOI-IN P. KELLY, of Wain emergency applications of the brakes may tertown, county of Jefferson, and State of New be sixty per cent. or more greater than that York, have invented an Improvement in Aircommonly employed in a similar equipment Brakes, oil which the following" description, as used on trains normally running at a conin connection with the accompanying draW- siderably lower speed. While the increased 55 ings, is a specification, like numerals on the brake-cylinder pressure is effective and desirdrawings representing like parts. able to reduce the speed of a rapidly-running This invention relates to an air-brake appatrain as soon as possible, it is likely to give IO ratus, and is shown as employed in an apparatoo great braking force after the speed of the tus of the kind commonly known as the autrain has been materially reduced and might 6o tomatic air-brake, in which the brake-cylinthen cause the locking of the Wheels, so that der is charged with air from an auxiliary resthey would slide on the rails, thus damaging ervoir on the oar under control of a triple the wheels and acting less effectively to bring I5 valve cooperating with the train-pipe, auxilthe train to a standstill than if the braking iary reservoir, and brake-cylinder to cause force were just'less than that which is suffi- 65 the brakes to be applied and released in recient to lock the wheels against rotation.

sponse to changes in pressure .of air in the The present invention is embodied in a retrain-pipe which may be controlled by the enlief-valve communicating With the brake-cylgineer. 1 inder and operating normally to prevent in- The present invention relates mainly to an creaseof brake-cylinder pressure beyond a 70 I appliance to 'be used in connection with the predetermined amount, said relief-valve havbrake-cylinder or with the-passage through ing combined therewith means whereby its which air is admitted to and exhausted from operation in response to the pressure in the 2 5 the brake-cylinder in the operation voi' applybrake-cylinder may be modiiied and deferred,

' ing and releasing the brakes, and is especially so that brake-cylinder pressure may be main- 75 applicable to brakes designed for use on trains `tained greater than that at which the reliefrunning at high speed. valve normally opens for a predetermined For very fast running trains it has been regulable period of time. The higher presfound desirable to provide greater power for surerabove that which normally operates the the brakes than isn employed in connection relief-valve to prevent further increase in 8O with rolling-stock of the same character which pressure is employed in emergency applicais regularly run at a consid erably lower speed, tions of the brakes and will be hereinafter reand one Way of providing for increased power ferred to as abnormal or excessive of the brakes is to increase the air-pressure brake-cylinder pressure, and the apparatus employed in the system beyond that commonly forming the subject oi the present invention 85 used on trains regularly running at a lower is intended to cause such abnormal'brake-cylspeed. For example,an equipment designed inder pressure to be maintained in emergency for use on trains regularly running at about applications of the brakes for a definite inter- 40 fortyv miles an hour asamaximum, and having val of time after the application has been the standard or normal air-pressure in the made, in which time the` speed of the train 90 train-pipe and auxiliary reservoirs seventy will have been materially reduced, and at the pounds, mightbe used with an air-pressure of end of said period of time the relief-valve will one hundred and ten pounds for trains regube opened and causeareduction of brake-cyllarly running at a maximum speed of sixty inder pressure to the normal amount or maximiles or more. In emergency applications of mum pressurethat is employed in service as the brakes the maximum pressure should be distinguished from emergency applications of attained in the brake-cylinders as promptly the brakes.

" as possible, and with a high-speed equipment The apparatus forming the subject oi' this the brake-cylinder to the atmosphere and a relieivalve proper, which normally retains said passage closed and is actuated in the direction to open the valver by the pressure in the brake-cylinder and in the direction to close the valve by a predetermined force, such as that of a spring, which may be set to retain any desired normal maximum pressure in the brake-'cylinder and which is overbalanced by an increase in said brake-cylinder pressure beyond said maximum to permit the relief-valve to open and permit the excess of pressure to escape.

The apparatus also comprises, in combination with such relief-valve, means for temporarily applying an additional i'orce actingI in opposition to brake-cylinder pressure on the relief-valve under certain conditions, such as those pertaining to an emergency application of the brakes, so that under said conditions the brake-cylinder pressure may be increased beyond that which normally overcomes the force for holding the relief-valve closed without overcoming the said normal force on the relief-'valve and the additional force applied thereto, so that the said abnormal or increased pressure is maintained in the brake-cylinder. Means are also provided whereby the additional or abnormal force tending to prevent opening of the relief-valve is gradually reduced, so that at the end of a regulable period of time the brake-cylinder pressure will overcome the resistance to the opening or' the relief-valve, and the additional force tending to close the relief-valve will finally be entirely withdrawn, so that the relief-valve will cause the brake-cylinder pressure to be reduced to the normal maximum amount, beyond which it is not substantially increased in the regular service applications, in which the additional force for closing the relief-valve is not brought into action.

Figure 1 is a longitudinal section of an airbrake appliance forming the subject et' this invention, the parts being shown in normal position occupied when the brakes are released. Fig. 2 is a diagram view showing the main components of a car equipment of an automatic air-brake apparatus provided with means for controlling the brake-cylinder pressure in accordance with this invention, and Figs. 3 and 4 are sectional details of a portion of the apparatus shown in Fig. l in different positions occupied in the operation and also illustrating certain modifications which Will be explained.

rlhe appliance forming the subject of this invention, which will be called a brake-cylinder relief-valve, is shown at 2 in Fig. 2 in connection with the usual car equipment of what is commonly known as the quick-ae tion automatic air-brake system, said car equipment comprising also the auxiliary reservoir 3, brake-cylinder 4, and quick-action triple valve 5, which latter is connected with the train-pipe 6 and controls the various communications that are called into action in the handling of the brakes namely, an exhaustpassage from the brake-cylinder to the atmosphere which is opened ior releasing the brakes and is closed preparatory to applying the brakes and a communication 7 8 from the auxiliary reservoir 3 to brakecylinder Ll, which is opened and closed in making graduated applications or' the brakes, and a communication (not shown) from the train-pipee to the auxiliary reservoir 3, which is opened when the brakes are released for recharging 'of the auxiliary reservoir up to the pressure normally carried in the train-pipe. The details of the car equipment, and especially of the triple valve, are not fully shown, as they may be of any usual construction, and such apparatus is in extensive use and well known to those familiar with this art.

For a proper understanding oi the reliefvalve 2, forming the subject oi' this invention, it is suiiicient to state that normally when the train is running with the brakes released the pressure in the auxiliary reservoirs 3 throughout the train is substantially equal to that maintained in the train-pipe (3 and that upon a reduction in train-pipe pressure the exhaust from the brake-cylinder to the atmosphere is closed and communication from the auxiliary reservoir to the lnake-cylinder established until the iow ot' air from the auxiliary reservoir into the brake-cylinder reduces the pressure in the former to that established by the engineer in the train-pipe, after which the communication from the auxiliary reservoir to the brakec\i'linder is closed with the pressure in the auxiliary reservoir again substantially equal to that in the trainpipe, which condition is maintained until a further increase of braking vlorce is required, which is accomplished by permitting pressure to escape from the train-pipe and causing the communication from the auxiliary reservoir to the brake-cylinder to be opened and again closed when the auxiliary-reservoir pressure has equalized with the newly-established pressure in the train-pipe. A moderate reduction in train-pipe pressure thus permits a relatively small amount of air to ilow from the auxiliary reservoir into the brakecylinder and applies the brakes with modera te pressure, and the braking pressure may beincreased in response to further diminutions'in train-pipe pressure until the increasing brakecylinder pressure equalizcs with the Falling auxiliary-reservoir pressure,at which time the maximum braking force is attained, and fur ther reduction in the train-pipe pressure produces no change in the condition oi the brake apparatus. A sudden reduction in train-pipe pressure to or below the said pressure o l eq uali- Zation of the auxiliary reservoir and brake-cylinder air or maxnnum brakmg pressure causes IOO IlO

the communication between the auxiliary res-y.

sponse to such reduction in train-pipe pres-V sure, which is made by the engineer in case of emergency or is made in the event of the breaking of the train-pipe in any way, 'as by the parting of a coupling'. For convenience of' referring to concrete conditions it may be assumed that a pressure of one hundred and ten pounds is normally carried in the system (in the train-pipe and auxiliary reservoirs) and'that this would give a braking pressure of eighty-ivepounds in the brake-cylinder, as the pressure of equalization in the brakecylinder and auxiliary reservoir when communicationis made and maintained between' the two, as in making an emergency application or' the brakes with no discharge-passage or relief-opening from the brake-cylinder. It may be assumed, furthermore, that sixty pounds pressure in the brake-cylinder is thel normal maximum, which is all that should be exerted in the brake-cylinder in making the usual service stops, or even emergency stops' after the speed of the train has become materially reduced, as a greater braking pressure applied when the train is moving-relatively slowly will be liable to lock the wheels and cause them to slide on the track, which is, as well known, highly objectionable. the brake apparatus proportioned and charged vvas just assumed it is possible to'obtain as a maximum eighty-live pounds pressure in the brake cylinder, and if the apparatus comprised only the usual equipment this could be produced in service applications of the brakes by the successive increases `in brake-cylinder pressure or by a relatively slow continuous iiowof air from the auxiliary reservoir to the brake-cylinder, such as is produced in making a full,A service application of the brakes, in which the engineer causes the train-pipe pressure to be continuously reduced, but at a comparativelyy slow rate. The appliance forming the subject of this invention is for the purpose or' preventing brake-cylinder pressure beingv increased substantially beyond the desired predetermined maximum', assumed to be sixty pounds in the brake-cylinder in service applications, but to permit of its being applied pressure for a certain period oi' time, after which it is reduced to the normal maximum of sixty pounds. The relief-valve 2, which contains instrumentalities for accomplishing these results, is connected by a duct or passage l9 with the brake-cylinder t, said passage 9 With f stitutes the relief-valve proper, said abutment controlling one or more grooves or passages 12 in the cylinder in which it works, which passages are open or uncovered when said piston 11 is moved away from the chamber 10 by the brake-cylinder pressure exerted therein, so thatair may then pass from said chamber 10 through said passages 12 into the space or spring-chamber 13 at the other side of said piston, which chamber has an opening or escape-passage 14 to the atmosphere. The brakecylinder pressure in the chamber 10, acting upon the piston 11, is opposed by a predetermined force, such as that of the spring 15, the i .mal maximuml desired to be carried in the brake-cylinderfor example, sixty poundsso that as soon as the brake-cylinder pressure rises above sixty pounds it issuiiicient to overcome the force of the spring 15 and if no other agency is called into action will then move the piston 11 to'open the passages 12 and permit air to escape from the chamber 10 and brake-cylinder until its pressure is no longer suficient to overcome spring 15, which will then move back the piston 11 and prevent further escape of air from the brake-cylinder through the relief-valve.. The appliances thus far described, therefore, operate like an ordinary relief-valve or safety-valve to prevent substantial increase of pressure in the brakecylinder beyond that which is suiicient to overcome the spring action on the relief-valve and cause the same to be opened.

In order to prevent the relief-valve from opening when an excess of pressure is desired tov be produced and maintained for a certain period of time in the brake-cylinder, as in the case of an emergency application of the brakes, means are provided for augmenting or supplementing the force of the spring 15 in opposition to the brake-cylinder pressure in the chamber 10 acting on the piston 11. This supplemental force, as shown in this instance, is derived from a fluid-pressure in the chamber 17 acting upon a supplemental piston or movable abutment 18, the stem 19 of which isy adapted to cooperate with the piston 11. Normally and during service applications of the brakes the fluid-pressure in the chamber 17 is substantially equal to that in the chamber 20 at the opposite side of the piston 18, which then is in balanced condition -and is in its position nearest to the piston 11, as shown in Fig. 1. A light spring may be used, as shown at 21, to retain the piston 18 normally in the position shown in Fig. 1 when the Huid-pressures on said piston 18 are balanced. In this position there is suhcient space between a head IOO or enlargement 22 on thepiston rod or stem `11 before the parts 22 23 come into engagement. If, however, the pressure in the chamber 2O is reduced below that in the chamber 17, the piston 18 will `be moved in the direction away from the piston 11 far enough to bring the enlargement 22 near enough to the shoulder 23 to prevent operative movement of the piston 11 without also engaging` and carrying the piston 18 in the same direction that said piston 11 moves in opening the ventpassage 12. (See Fig. 3.) Vith the parts in this latter position, therefore, the brakeeylinder pressure in the chamber 10 before it can open the vent 12 must overcome not only the force of the spring 15, but also the fluid-pressure in the chamber 17 acting on the piston 18, and consequently a corresponding increase in brake-cylinder pressure may be made before the vent-valve can be opened to prevent a still further increase in said brakecylinder pressure. In order to provide for the requisite pressure conditions in the chambers 17 and 2O to control the piston 18, the said chamber 17 is made of suiicient size, or, preferably, for convenience `of construction, is placed in communication with a small reservoir 24, to contain a supply of air to act upon the piston 18 when it is desired to supplement the force of the spring 15. The said chamber or space 17 and 211 is charged from the chamber 20, which is placed by a pipe or duct 25 in communication with some part of the air-brake system in which the proper Apressure conditions exist-such, for example,

as the auxiliary reservoir 3 or train-pipe 6- it being deemed desirable to make said connection with the auxiliary reservoir, as shown in Fig. 2, although it is to be understood that there is no limitation to this specific arrangement. rlhe space 17 24 is supplied or charged through a small passage 26 through or around the piston 18, said passage being shown in Fig. 1 as a groove in the wall of the cylinder in which the piston 18 works and being shown in Fig. 3 as a small opening directly through the piston 18. Air may thus flow at a comparatively slow rate from the chamber at one side to the chamber at the other side of the piston 18, according as the pressure at one or at the other side is greater, and normally the chamber 17, together with the reservoir 24, (which is practically only an extension of said chamber 17 and may therefore be hereinafter understood as included therein,) is charged to the same pressure as normally maintained in the system4 c., in the train-pipe and auxiliary reser voirs-with which the chamber 2O communicates. When train-pipe pressure and auxiliary-reservoir pressure are reduced comparatively slowly, as in making' service applications of the brakes,the air willflow from the chamber 17 into the chamber 20, so as to reduce the pressure in the chamber 17 at about the same rate as that in the chamber 20,thus leaving the piston 11 under the sole control of the spring 15 and brake-cylinder pressure in the chamber 10, so that the relief-valve is opened as soon as the brake-cylinder pressure begins to exceed the normal maximum desired `for service applications of the brakes, and eonsequently although the system is supplied with air suliicient to give a greater brake-eylinder `pressure the desired maximum will not be exceededin service applications of the brakes.

WVhen, however, the train-DDC DYCSSUm is "0' duced suddenly, as in making an emergency application of the brakes, the auxiliary-reservoir pressure is also reduced suddenly, and consequently the pressure in the chamber 20 is reduced suddenly whether said chamber is connected with the train-pipe or auxiliary reservoir, and the pressure in the chamber 17 is prevented from equally rapid reduction by the smallness of the passage 2G relative to the capacity of the chamber 17, (including 21,) so that the pressure in 17 on the piston 18 is unbalanced and moves the said piston away lrom the piston 11 and so as to engage the shoulders 22 23, so that the piston 11 cannot be moved to open the relief-passages 12 except by brake-cylinder pressure in chamber l() suflieient not only to overcome the spring l5, but also the added resistance of the lluidspres sure in the chamber 17 acting on the piston 18. (See Fig. 3.) r1`he parts may be so proportioned that the additional pressure on piston 18 is suiiicient to overcome the additional or abnormal pressure produced in the brakecylinder from all sources in making an emergency application of the brakes, so that said pressure will be retained in the brake-cylinder unaffected by the presence of the relielvalve 11 in the apparatus. This condition, however, is prevented from being continued too long by the fact that the pressure is escaping from the chamber 17 through the passage 26 0r through such other escape as may be provided, and therefore the additional force preventing the opening of the relielvalve 11 is gradually diminished until linally the brake-cylinder pressure is sullicient to open the relief-valve, and as the pressure in the chamber 17 becomes linally exhausted or equalized with the pressure remaining in the chamber 20 the brake cylinder pressure finally encounters only the resistance ol the spring 15, the same as in service applications of the brakes, and is reduced by escaping through the relief-passage tothe normal maxi mum exerted in the service applications.

rhen the chamber 2() is connected with the auxiliary reservoir 3, as shown, the back llow or discharge of air from the chamber 17 is into the auxiliary reservoir and thence into the brake-cylinder; but, as before stated, this arrangement is not necessary, the important matter being that the chamber 17 should contain air at a higher pressure than the ehamber 20 at the moment when an emergency aplOO plication'of the brakes is made and that the pressures in said chambers should be normally approximately equal and should equalize after a predetermined time interval in which that in the chamber 17 remains in preponderance.

Where the chamber 17 is supplied by a groove, as shown at 26 in Fig. 1, said groove may be of suflicient size to cause the pressures to equalize with reasonable promptness; but when tbe pressure in 20 is suddenly reduced the movement of the piston 18 in response tok the then preponderating pressure' in 17 may partially close said passage 26, so as to give the required time before the' pressure in` 17 willv fall suiiicientlyl to allow the brake-cylinder pressure to be relieved. y

The parts are shown in Fig. t in the position occupied when the relief-valve is open and air is escaping through or past the' same from the brake-cylinder to the atmosphere.

The lost-motion connection at 22 23 between the relief-valve-actuating abutment 11 and the supplemental abutment or piston 18 is not essential, as the piston 18 might move with the piston ll-when the pressures on piston 18 are approximately equal; but the said lostmotion connection is desirable, as it leaves the piston 11 unaffected except by the spring 15 in the usual operations, which take place except in emergency applications.

I claim- 1. An automatic fluid-pressure brake system comprising an auxiliary reservoir, a triple valve and a brake-cylinder combined with a relief-valve controlling an escape-passage from the brake-cylinder, said relief-valve being acted upon by brake-cylinder pressure tending to open the same, and a predetermined force op'posed to said brake-cylinder pressure; and means for temporarily augmenting the said opposing force; substantially as and for the lpurpose described.

2. The combination with the auxiliary reservoir, triple valve and brake-cylinder; of an automatic Huid-pressure brake, with a brakecylinder relief-valve controlling an escapepassage from the said brake-cylinder, and means for delaying the opening of said valve whereby an abnormally high pressure may be retained in the brake-cylinder for a determinable period of time before the relief-valve is opened, substantially as and for the purpose described.

3. A relief-valve comprising a dischargevalve and movable abutment controlling the operation of the same, exposed at one side to the fluid-pressure to be relieved, and at the otherv side to a predetermined opposing force; and means for augmenting said opposing force, whereby the huid-pressure required to open said valve may be increased, substantially as described.

4;. The combination of the train-pipe, auxiliary reservoir, brake-cylinder, and triple valve of an automatic air-brake apparatus, with a brake-cylinder relief-valve and movable abutmentl or actuator therefor, exposed at one side to brake-cylinder pressure, and at the other to a predetermined opposing force, a supplemental movable abutment coperat- Aing with the valve-actuating abutment and exposed at opposite sides to fluid-pressures which are normally equal; and means for reducing the pressure at one side ofthe said supplemental abutment relative to that at the other side, in response to an emergency application of the brakes.

5. vThe combination of the train-pipe, auxiliary reservoir, brake-cylinder, and triple valve, of an automatic air-brake apparatus, with a brake-cylinder relief-valve actuated by brake-cylinder pressure, and a supplemental movable abutment having an operative connection with said relief-valve and exposed to fluid-pressures on both sides, and a connectingpassage between the fluid-chambers at opposite sides of said supplemental piston whereby the pressures inl said chambers equalize in a determinable period of time after one of said pressures is in preponderance over the other.

In testimony whereof I have signed my name to this specification in the presence of two sub- J No. F. MALONEY, W. F. NIooL.

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