US1302985A - Triple valve - Google Patents

Description

J. R. SNYDER.

1mm VALVE. APPLICATION FILED SUN 18.1915. RENEWED FEB-17,1919- I 1,302,985. I Patented May 6, 1919.

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FIG. 1

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J. R. SNYDER.

TRIPLE VALVE.

APPLICATION FILED SEPT. 18. I915, RENEWED FEB. 11. 1919.

1,302,985. Patented May 6, 1919;

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FIG. 2

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JACOB RUSH SNYDER, OF PITTSBURGH,PENNSYLVANIA, ASSIGNOR TO PERCY BONNER, OF PITTSBURGH, PENN SYLVANIA.

TRIPLE VALVE,

Specification of Letters Patent.

Patented. May e, 1919.

Application filed September 18, 1915, Serial No. 51,436. Renewed February 17, 1919. Serial No. 277,652.

To all whom it may concern:

Be it known that I, JACOB Rusrr SNYDER, a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Triple Valves, of which the following is a specification.

This invention relates to triple, control and distributing valves for air brake sys-' interfering with the functions of modern forms of tr1ple and control valves, and lrrespective of whether the main piston has an emergency position or not.

With present forms of quick action triple,

control and distributing valves, it frequently;

happens that the main piston fails to move to service application position upon initial or subsequent service reductions of train pipe pressure. This may be due to many different causes, such as insufficient or iml perfect lubrication, improperly fitted pa-cln ing rings, binding of packing ring and piston, dirt or foreign substance in the valve, clogging of the service port, and numerous other well known causes. As a result of the failure of the valve to move upon service reduction of train pipe pressure, substantially the full auxiliary reservoir pressure is retained on the auxiliary reservoir side of the main piston, so that when the valve does move under a second or subsequent service reduction of train pipe pressure, the excessive pressure on the auxiliary reservoir side moves the piston over so violently that the standard graduating spring does not arrest its movement in service position and an undesired emergency application is unintentionally brought about. This invariably means pulling out of draw bars or some the operation of the main triple valve piston, so that no matter how much said pistonmay stick, and no matter how violently or how far it moves over toward the graduating stem, undesired quick action can not possibly occur, but, moderate or service reductions of train pipe pressure will invariably produce service action, and emergency action can only be produced by a sudden, heavy reduction in. train pipe pressure.

p A further object -of the invention is to provide improved means for preventing undesiredemergency application, which can be readily applied to all standard forms of triple, control or distributing'valves now in use, whether the main piston of said valves has an emergency position or not, and which will not interfereywith any of the usual or normal functions ofsuch valves.

A further object of the invention is to provide improved means for preventing undesired quick or emergency application, which is more easily operated-and controlled, is more positive in action and which is more compact andless cumbersome than prior constructions forthis purpose.

Furtherobjects of the invention are in part obvious and in part will appear more in detail hereinafter;

In the drawings, which represent one embodiment'of my invention, Figure 1 is a vertical sectional elevation, showing the parts in normal releaseposition; and Fig. 2 is a similar view, showing the parts in 'emergency application position.

The triple valve shown comprises the usual casing 1 provided with the chamber 2 in which works the main piston 3, the bushing of said chamber being provided with the usual auxiliary reservoir charging groove laround the piston when in normal release position. The auxiliary reservoir is connected at 5 and the brake cylinder at 6, while the train pipe connects through a passage 7 to chamber 8 in the'head 9 from which communication is had through ports 10 with the main piston chamber 2, all-as is usual in standard Westinghouse triple valves. In the head 9 is the usual graduating stem 11 acted upon by a graduating spring 12. I

The stem 13 of the piston 3 actuates the main slide valve 14: and the graduating valve 15, the former having a lost motion connection with the piston stem 13, while the graduating valve has no lost motion connection with said stem, said valves being shown as tandem valves both sliding directly upon the seat 16. A bushing 17 pressed inwardly by a spring 18 is provided with a projection 19 adapted to contact with the main slide valve 14 and push the same from retarded release position to full release position, as is customary in this type of triple valve.

The seat 16 for the slide valves is provided withtwo exhaust ports 20, 21, leading to the atmosphere, and with two ports 22, 23, both of whichcommunicate with the brake cylinder connection 6 through passages in the casing which lead to the chamber 24 which, in the standard Westinghouse triple valve, is above the emergency valve piston,

but which here is in communication with the brake cylinder connection 6 so that ports 22 7 necessary to illustrate the cavity 24 in the main valve 14, which in retarded release position connects therestricted brake cylinder port 22'to the exhaust port 21, and the cavity 25 of the graduating valve, which in normal release position connects the brake cylinder port 23 to the exhaust port 20.

On a moderate or service reduction in train pipe pressure the main piston 3 moves.

clear over to the position shown in Fig. 2, compressing the graduating spring 12, and the main valve 14 uncovers brake cylinder port 22, so that auxiliary reservoirpressure flows to the brake cylinder. The train pipe may also be vented to the brake cylinder through a restricted port in the valve seat, so as to produce quick serial action through out the train, as will be readily understood,

On a sudden heavy reduction of train pipe pressure for securing emergencyaction the connection between the auxiliary reservoir and brake cylinder is again through the port 22, and there may or may not be venting of the train pipe by the main valve mechanism, as desired. The emergency function, however, is taken care of entirely independently of the main triple piston and the valves op-- erated thereby, and-by the improvements now to be described.

The usual Westinghouse emergency piston and valves, with the bushing and casting member inclosmg the stem are bodlly removed and are replaced by the emergency valve mechanism now to be described. This valve mechanism comprises a casing 26 which is secured to the main casing in lieu of the corresponding Westinghouse casing connection, and which is provided with the train pipe connection 27 communicating with chamber 28 which in turn communicateswith the passage 7 in the main casing. Casing 26 has an upwardly extending hollow portion 29 which lies within and communicates through a large opening 30 with the chamber 24, said upwardly extending portion 29 being threaded at its lower end to receive a bushing 31 and at its upper end to receive a guide plug 32 for the stem of a downwardly seating check valve 33 held to'its seat onthe upper end of the bushing 81 by aspring 34.

The lower end of the bushing31 forms a seat for an upwardly seating check'valve 35 having a stem working in a cavity in asupplemental casmg 36' attached 'tothe casing 26, the lower portion of said valve being in the form of a piston 37- sliding in a bushing 38 in the sub control chamber 39', said bushing being provided with a largefeed groove 40 for a purpose which will=morefully herelnafter appear. Gheck valve 35' is normally held to its seat by the pressure in the sub control chamber 39 and by a spring 41 in said chamber.

In the lower portion of the casing; 86 is a control chamber 42 communicating through a passage in a cap 43 with the space'4'4 on one side of a diaphragm 45, which liesop posite and cooperates w-itha movable piston or abutment. 46 working in a, chamber 47 which communicates through a cored out passage 48 with the chamber 28 of thecasing 26. The diaphragm 45 andth'e movable piston 46 are provided with .small-alinedequalizing or feed p0rts49i The stem 50 of the piston 46 is provided with a longitudinal feed groove 51, which in normalposition of the emergency valve mechanism, as in Fig. 1, connects the chamber '47 to the sub control chamber 89, but in emergency position, as

shown in Fig. 2, is sealed bythe shoulder, 51*, so as to cutoff the flow of pressure from the train pipe to the sub. control chamber 39, as will be readily understood. The inner end of the piston stem 50engages a lateral extension on a small groovedcheclrvalve 52, which is normally held to its seat 53, as shown in Fig. 1, by a spring 54, and closes communication between the sub control chamber 39 and an exhaust port 55.

Normally the parts are in the position shown in Fig. 1, with train pipe pressure inthe chambers 2 and 28, and equalized. through charging groove 4 to" the auxiliary reservoir side of the main piston 3, and also through the passage 48 to the chamber 47 on the train pipe side of the piston 46, thence through the equalizing. ports 49 to the control chamber 42 and through feed groove 51 to the sub control chamber 39. The brake cylinder port 23 in the valve seat is connected by passage 25 in the graduating valve 15 to exhaustport 21, while all other ports and valves are tight or closed. 7

Upon service reductions of train pipe pressure the auxiliary reservoir pressure moves the main piston 3 and the slide valves connected thereto to connect the auxiliary reservoir to the brake cylinder through the port 22. The equalizing ports 49 through the diaphragm 45 and piston 47 are of such size as to permit the pressure in the control chamber 42 to equalize therethrough as rapidly as the train pipe pressure is reduced in service reductions, so that piston 47 does not move and communication is maintained from the train pipe through passage 48, chamber 47 and groove 51 to the sub control chamber 39. Consequently, equalization of pressures is maintained on the upper and lower faces of the check valve and said valve does not unseat, and this is the case no matter how many times the train pipe pressure may be reduced byservice reductions and entirely irrespective of whether the main piston 3 sticks or not. Moreover, if the emergency valve mechanism has been attached to some standard form of triple valve, such as the ordinary Westinghouse triple valve in which the valve seat is provided with a port opened when the piston reachesemergency position, said port will communicate with the chamber 24*, and movement of the piston to emergency position will merely produce a service action of the brakes by direct flow of auxiliary reser voir pressure to the brake cylinder through said port. Consequently, even though the main piston sticks during the first or second service reductions of train pipe pressure and moves over very violently uponthe third or later service reduction of train pipe pressure, or moves to the normal emergency position of said piston, no movement whatever of the check valve 35 can occur and evacuation of the train pipe and an undesired quick emergency action of the brakes will not be efl'ected.

When, however, the train pipe pressure is heavily and suddenly reduced, such as by a bursted hose or in making an emergency application, the pressures on the opposite faces of the diaphragm 45 and piston 46 can no longer equalize through ports 49 with suflicient rapidity. Consequently the preponderance of pressure in control chamber 42 moves the diaphragm 45 and piston 46 inwardly or to the position shown in Fig.2, thereby unseating the small valve 52 so that the pressure in the sub C011".

trol chamber 39 is evacuated to the atmosphere through the exhaust port 55. This leaves the valve 35 subject on its lower face to the pressure of the spring 41 and on its upper face to atmospheric pressure withinthe bushing 31 and to the train pipe pressure in chamber 28, which pressure unseats said valve and moves it downwardly into the sub control chamber 39. chamber 28 thereupon lifts the .check valve 33 and rushes through the chamber 24 to the brake cylinder, thereby securing the necessary quick application of the brakes and the local reduction in train pipe pressure to give the desired quick action. The main piston has, of course, moved fully over to its emergency position and connects the auxiliary reservoir to the brake cylinder, but this gives merely the usual flow of air from the auxiliary reservoir to the brake cylinder so as to give full opportunity for the train pipe to vent to the brake cylinder.

The shoulder at the outer end of the feed groove 51 in the piston stem 50 closes communication between the chamber 47 and the sub control chamber 39 as soon as the piston 46 moves inwardly, which prevents a rush of air through the passage 48 into the sub control chamber 39 until valve 35 has been forced from its seat, in which position of valve 35 air from the chamber 28 passes to the sub control chamber through the feed groove 40, which is larger than the exhaust groove in the check valve 52, thus enabling.

the pressure to build up in chamber 39 an equalization to take place between the train pipe passage and the sub control chamber. The pressure in chamber 42 has in the meantime equalized with the train pipe pressure through feed grooves 49 and passage 48 so that the piston 46 and diaphragm 45 are returned to their original position by the spring 54. This equalization is secured immediately after equalization takes place between the train pipe passage 28 and the brake pipe chamber 24, whereupon valve 35 is returned to its seat by the spring 41, and equalization follows between the train pipe passage 28, chamber 47 and the control chamber 42. a

With this valve mechanism undesired quick emergencyaction cannot possibly occur, due to the fact that emergency action is entirely independent of the main triple piston, and irrespective of whether the emergency attachment is on a special form of triple valve or one of the standard triple .valves having the usual emergency ports,

passages and position. Nevertheless, quick emergency action is invariably produced by any heavy, sudden reduction of train pipe pressure. The improvements do not interfere in any way with any of the usual normal functions of modern triple valves, which can operate in the same manner as usual, thereby enabling this emergency valve mechanism to be attached to such valves without any modification therein. Furthermore, the valve mechanism described enables the use of a large opening through the bushing connecting the train pipe passage The pressure in the to the brake cylinder chamber 24, as the check valve closing said opening is not held to its seat by pressure effective over a large area at the time of opening said valve for producing emergency action, as in prior constructions, but the pressure beneath said valve is evacuated so that the train pipe pressure need only overcome the pressure of a comparatively light spring. The valve mechanism is also more certain in operation becauseit is controlled entirely by the small check valve 52, which evacuates the pressure in the sub control chamber 39 to the atmosphere, andonly a slight preponderance of the pressure in the control chamber 42 over that in the chambers 49 and 39', due to the sudden reduction in train pipe pressure, is requiredto open said valve. Consequently the control chamber 42 need be merely a small chamber so' that the attachment is compact and not cumbersome.

An additional advantage secured by the use of the attachmentherein'described is that one triple valve may be used for operating the brakes under different pressures in the train pipe witho'ut'causing kicking 0r dynamiting of the brakes. When a train is. made up of empty cars the pressure in the air brake system is generally in the vicinity of lbs, whereas, when a train is made up of loaded cars, a pressure of from 90 to 110 lbs. is frequently used. The increase in train pipe pressure causes more water or moisture to be condensed in the air, brake system and this water forming, in and passing through the usual type of triple valve causes more frequent occurrence of the" kicking or undesired emergency-at the time service action is desired.

In order to, avoid increasing the train pipe pressure beyond 90 lbs. for obtaining the required additional braking power on mountain grades, systems have been devisedin 7 which an additional set of brakes have been provided which must berendered operative on .each'car when the car is loaded, and, when the car 1s empty, the extra set of brakes must bea ain shut 0a. This du li-v (3913011 of parts increases expenses and complicates the system. I

The attachment herein disclosed enables a single triple valve to be used with both hi h and low pressures without danger of the valve causing undesired emergency re gardless of moisture or other detrimental conditions that may arise. For example, when a pressure of 70 lbs. isused on an unloaded train, the attachment prevents undesired emergency, for reasons explained in the description of the valve. Also, when a pressure of 110 lbs. or more is used the attachment operates equally as well to prevent undesired emergency. Consequently there is no danger of undesired emergency action under either higher low pressures ing this result without complicating the system and unduly increasing the expense and Without requiring the manual re-setting of mechanism on each of the cars, are obvious.

What I claim is 1. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variationsin train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said emer gency valve being subject on one side to train pipe pressure and on the other side to a trapped pressure, and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon sudden reductions in train pipe pressure to evacuate said trapped pressure, whereby to open said emergency to a trapped'pressure, means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon sudden reductions in train pipe pressure to evacuate'said trapped pressure whereby to open said emergency valve, and means for closing said emer-- gency valve upon equalization of train pipe and said trapped pressures.

3. In a triple, control or distributing valve mechanism, the combination of amovable abutment actuated by variations in train .i e Jressure valve mechanism actuated P P I a hereby and arranged upon service reductions in train pipe pressure to control communication oetween the auxiliary reservoir brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other to a trapped pressure, a spring tending to close said valve, and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon sudden reductions in train pipe pressure to evacuate said trapped pressure whereby to open said emergency valve.

4. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other to a trapped pressure, a spring tending to close said valve, means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon sudden reductions in train pipe pressure to evacuate said trapped pressure whereby to open said emergency valve, and means arranged upon equalization of train pipe and said trapped pressures to restore the trapped pressure effective upon said valve.

5. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other to the pressure in a chamber, said chamber being provided with an exhaust opening, and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged to open said exhaust upon a sudden reduction of train pipe pressure, whereby to open said emergency valve.

6. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other to the pressure in a chamber, said chamber being provided with an exhaust opening, means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged, to open said exhaust upon a sudden reduction of train pipe pressure, whereby to open said emergency valve, and means for closing said emergency valve upon equalization of train pipe and said chamber pressures.

7. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure, and on the other side to the pressure in a chamber, said chamber being provided with an exhaust opening, a spring tending to close said emergency valve, and means for opening said exhaust upon a sudden reduction of train pipe pressure, whereby to open said emergency valve.

8. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other to a trapped pressure, a check valve for controlling a vent for said trapped pressure, and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon a sudden reduction in train pipe pressure to open said check valve.

9. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actu ated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reser voir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pres sure and on the other to a trapped pressure, a check valve controlling a vent for said trapped pressure, means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged upon a sudden reduction in train pipe pressure to open said check valve, and a spring tending to close said emergency valve.

10. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communicationto the train pipe and brake cylinder, and a movable abutment so located as to allow unobstructed connection between the movable abutment and the train pipe and actuated by variations in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to open said emergency valve.

11. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve 7 controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pres sure and on the other side t0 the pressure of a chamber, and a movable abutment so located as to allow unobstructed connection between the movable abutment and the train pipe and actuated by variation in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to evacuate the pressure of said chamber, whereby to open said emergency valve.

12. In a triple, control or distributing valve mechanism, the combination of a mo able abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other side to the pressure of a chamber, a movable abutment so located as to allow unobstructed connection between the movable abutment and the train pipe and actuated by variation in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to evacuate the pressure of said chamber, whereby to open said emergency valve, and means arranged upon equalization in train pipe and said chamber pressures to close said emergency valve.

13. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism act,u ated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other side to the pressure in a die nber, said chamber being provided with an exhaust opening, and a movable abutment operated by variations in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to open an exhaust from said chamber.

141. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reser voir and brake cylinder, an emer ency valve controlling a direct connnunication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other to the pressure in a chamber, said chamber being provided with an exhaust opening, a movable abutment operated by variations in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to open an exhaust from said chamber, and means arranged upon equalization of train pipe and said chamber pressures to close said emergency valve.

15. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reser voir and brake cylinder, an emergency valve controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pres sure and on the other side to the pressure of a chamber, a spring tending to close said emergency valve, and a movable abutment operated by variations in train pipe pressure and arranged upon a sudden reduction in train pipe pressure to evacuate the pressure of said chamber, whereby to open said emergency valve.

16. In a triple, control or distributing valve mechanism, the combination of a movable abntment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reduction in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve independent of said movable abutment and controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other side to the pressure of a chamber, a check valve controlling an exhaust from said chamber, and a movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and arranged upon sudden reductions in train pipe pressure to actuate said exhaust valve.

17. In a triple, control or distributing valve mechanism, the combination of a movable abutment actuated by variations in train pipe pressure, valve mechanism actuated thereby and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder, an emergency valve independent of said movable abutment and controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other side to the pressure of a chamber, a check valve controlling an exhaust from said chamber, a movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and arranged upon sudden reductions in train pipe pressure to actuate said exhaust valve, and means arranged upon equalization of train pipe and brake cylinder pressures to close said emergency valve.

18. In a triple control or distributing valve mechanism, the combination of a main movable abutment communicating directly with the train pipe pressure, valve mechanism actuated by the abutment and arranged upon service reductions in train pipe pressure to control communication between the auxiliary reservoir and brake cylinder of an air brake system, an emergency valve independent of the main abutment and controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other side to a trapped pressure, and means arranged to vent the trapped pressure to atmosphere upon sudden reductions in train pipe pressure, but to remain inoperative to vent said pressure under service reductions in train pipe pressure.

1.9. In a triple control or distributing valve mechanism, the combination of a main movable abutment communicating directly with the train pipe pressure in an air brake system, valve mechanism actuated by said abutment arranged to control communication between the auxiliary reservoir and brake cylinder, an emergency valve independent of said movable abutment and controlling a direct communication between the train pipe and brake cylinder, said valve being subject on one side to train pipe pressure and on the other side to a trapped pressure, and a second movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and arranged so that upon sudden reductions of train pipe pressure it vents the trapped pressure behind the valve to atmosphere to permit said valve to open communication between the train pipe and brake cylinder, said second abutment being also arranged so that it is not moved by service reductions in train pipe pressure.

20. In a triple control or distributing valve mechanism, the combination of a main movable abutment communicating directly with the train pipe pressure of an air brake system, valve mechanism actuated by said abutment and arranged to control communication between the auxiliary reservoir and brake cylinder, an emergency valve independent of said movable abutment and controlling a direct communication between the train pipe and brake cylinder, said emergency valve being subject on one side to train pipe pressure and on the other side to a trapped pressure in a chamber, a check valve controlling a vent from said chamber to atmosphere, and a second movable abut,- ment subject on one side to train pipe pressure and on the other side to a trapped pressure and arranged so that upon sudden reductions of train pipe pressure it actuates the check valve to vent the trapped pressure behind the emergency valve to atmos phere to permit said valve to move to open communication between the train pipe and the brake cylinder, said second abutment being also arranged so that it is not moved by service reductions in train pipe pressure. 21. An attachment for standard; triple valves comprising mechanism arranged to be attached to a triple valve without altering the construction thereof for venting the train pipe pressure to the brake cylinder of an air brake system, said mechanism including a movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged to vent the trapped pressure upon sudden reductions in train pipe pressure but to prevent such venting upon service reductions of train pipe pressure, whereby venting of the train pipe pressure to the brake cylinders under service reductions is prevented without interfering with such venting under emergency reductions.

22. An attachment for triple valves which have emergency mechanism for venting the train pipe pressure to the brake cylinder of an air brake system, comprising means arranged to be substituted for said emergency mechanism and to be applied to the triple valve without altering the construction thereof for venting the train pipe to the brake cylinders upon emergency reductions in train pipe pressure but preventing such action under service reductions in train pipe pressure, said mechanism including a movable abutment subject on one side to train pipe pressure and-on the other side to a trapped pressure and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged to vent the trapped pressure upon emergency reductions in train pipe pressure.

23. The combination with a triple valve provided with an emergency mechanism for venting the train pipe pressure to the brake cylinders ,of an air brake system, of mechanism arranged to be substituted for said emergency mechanism and to be applied to the triple valve without altering the construction thereof for venting the train pipe pressure to the brake cylinder upon emergency reductions in train pipe pressure but preventing such action under service reductions in train pipe pressure, said mechanism including a movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and means so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged to vent the trapped pressure upon sudden reductions in train pipe pressure.

241-. An attachment for triple valvesadapted to be applied to such valves without altering the construction thereof, comprising mechanism operating independently of the triple valve mechanism for venting the train pipe to the brake cylinder, said mechanism being provided with a movable abutment subject on one side to train pipe pressure and on the other side to a trapped pressure and means for venting the trapped pressure upon sudden reductions in train pipe pressure to cause the abutment to move to establishcommunication between the train pipe and the brake cylinder, said means being so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged so that it is not moved upon service reductions in train pipe pressure.

25. An attachment for triple valves provided with mechanism for venting train pipe pressure to the brake cylinder of an air brake system, comprising mechanism arranged to be substituted for the emergency mechanism and to be applied to the triple valve without altering the construction thereof, said mechanism comprising a valve arranged to be operated by train pipe pres sure and controlling a communication between the train pipe and the brake cylinders, a movable abutment for preventing operation of said valve, said abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, and means for venting the trapped pressure upon sudden reductions in train pipe pressure to operate the valve and vent itself to the brake cylinder, said means being so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged so that it is not moved byservice reductions in train pipe pressure.

26. An attachment for triple valves arranged to be applied thereto without altering the construction thereof, said attachment being connected so as to establish connnunication between the train pipe and the brake cylinder of an air brake system, a movable abutment normally closing said passage, a second movable abutment for preventing operation of the first, said second movable abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, means for venting the trapped pressure to atmosphere upon emergency reductions in train pipe pressure, whereby the second movable abutment is actuated to allow the first movable abut ment to be moved by train pipe pressure to vent the train pipe pressure to the brake cylinders, said means being so located as to allow unobstructed connection between the movable abutment and the train pipe and arranged so as not to move under service reductions in train pipe pressure.

27. An attachment for triple valves which have emergency mechanism for venting the train pipe pressure to the brake cylinder of an air brake system, comprising mechanism arranged to be substituted for the emergency mechanism and to be applied to the triple valve without altering the construction thereof, said mechanism comprising a movable abutment normally closing communication between the train pipe and the brake cylinder and arranged to be oper ated by train pipe pressure, a second movable abutment for preventing operation of the first, said second movable abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, a third movable abutment controlling a valvular mechanism for venting the trapped pressure, said third movable abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, whereby upon sudden reductions in train pipe pressure the third movable abutment is moved by the trapped pressure behind it to vent the trapped pressure behind the second movable abutment to atmosphere to allow said abutment to be moved to permit movement of the first abutment to vent the train pipe pressure to the brake cylin dcr, said third movable abutment being arranged to equalize the trapped pressure behind it with the train pipe pressure upon service reductions in train pipe pressure.

28. An attachment for triple valves which are provided with emergency mechanism for venting the train pipe to the brake cylinders of an air brake system, comprising mechanism arranged to be substituted for the emergency mechanism and to be applied to the triple valve Without altering the construction thereof, sald mechanism comprislng a movable abutment normally biased by a mechanism for venting the trapped pressure to atmosphere, said third abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, whereby upon sudden reductions in train pipe pressure the third movable abutment vents the trapped pressure behind the second abutment to atmosphere so that said second abutment is moved by train pipe pressure to permit said train pipe pressure to reach the first abutment and actuate the same and thereby vent itself to the brake cylinders.

29. An attachment for triple valves which are provided With emergency mechanism for venting the train pipe to the brake cylinders of an air brake system, comprising mechanism arranged to be substituted for the emergency mechanism and to be applied to the triple valve Without altering the construction thereof, said mechanism comprising an abutment normally biased to prevent communication between the train pipe and the brake cylinder and arranged to be operated by train pipe pressure to establish such communication, a second movable abutment for preventing the train pipe pressure reaching the first, said second abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure and the pressure of a spring, a third movable abutment controlling a valve mechanism for venting the trapped pressure to atmosphere and also controlling a communication between the train pipe and the trapped pressure chamber behind the second abutment, said third abutment being subject on one side to train pipe pressure and on the other side to a trapped pressure, whereby upon sudden reductions in train pipe pressure the third movable abutment is moved by the trapped pressure behind it to vent the trapped pressure from behind the second abutment to allow said second abutment to be moved by train pipe pressure to allow train pipe pressure to reach the first abutment and move the same to vent said pressure to the brake cylinder, said third movable abutment being provided with a feed groove for preventing its operation under service reductions in train pipe pressure and for permitting it to automatically return to normal position when moved under emergency reductions, said second abutment being also pro vided with a feed groove for permitting its return to normal position.

In testimony whereof, I have hereunto set my hand.

JACOB RUSH SNYDER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G.

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