US2274307A - Control mechanism for rail sanders - Google Patents

Description

Feb. 24, 1942. H. N. sUDDU'rH CONTROL MECHANISM FOR RAIL SANDERS Filed June 4, 1941 9 (D vx (l0 //I////// AV AV Umm n @Tl @N OM. @Nv

(Ittornegs Patentecl Feb. 24, 1942 t I wrm-3DA STATES PATENT orrlcli:v

CONTROL MECHANISM FOR RAIL SANDERS Henry Norton Sudduth, Watertown, N. Y., as-

signor to The New York Air Brake Company, a corporation of New Jersey Application June 4, 1941,*se1-ia1 No. 396,616

` cmms. -(c1.291 s This invention relates to sanding devices for .railway rails and particularly to a timing valve of simple form, to time cleanout blasts.

Applicants assignee has develop-edr commercially certain highly organized sanding equipment intended for use on all braked trucks of high speed trains and so `contrived as to be p ut into action by the brake system during certain types of brake application or even during all applications. Each set or group of sand traps is put into action by a piston actuated slide valve rmechanism which delivers 4first a cleanout blast, then a sustained sanding blast through a separate connection, and finally as the device shuts down gives a iinal brief cleanout blast.

The general `organization of the sand trap is .shown in the allowed application of Charles A. Campbell, Serial No. 314,173, filed vJanuary 16, 1940, issued as Patent No. 2,243,243, May 27,1941. These traps require the delivery of cleanout blasts through one connection and the delivery ,of sanding air through another. A y

Such traps are also desirable for single instal- )lation on the head ends of railway motor cars and on locomotives, but economy requires :the .use of a simple control valve ofthe manually voperable type where the Campbell trap is so used.

The present invention attains that result by the use of simple components.,` many of which .are

standard for other uses and hence commercially available at reasonable cost. Such an embodi' ment of the invention will now be described.

.In the dra-Wing: v Figure 1 is ,la `diagramrnatic elevation .of the manual valve,;the trap, `the relay anditiming vvalve assembly, and the pipe connections..

Figure 2 is al sectional jdiagramon a larger `s caleof the apparatus shown in Figure ,1, except the sand tra-p.4 Figur-e 3 is @section similar to a AIigure 2 but showing the-'manual sanding position. f

AReferring first to FigureA 1, `the vmanual valve :portion ,of valve set in appears at Il and Athesaufrd -trapat 12. This is fed by a .Sand bOX I3 anddel-versfsand to theral through :hose I4. `Apipe bracket` t5 carries the ,relay air valve unit lr6 I'and the timing valve ,unit ,I l, mounted on opposite sides thereof. :The valve `rII is mounted in the cab and the parts 15, n.15,

I] may be mounted at any convenient point.

`The lpipe connections are as follows: Air :supply pipe J8, leading from any suitable sourcefof com- Jpressed air, sanding-,actuation pipe I9, fnnal -airtpirej 21,3.

The manual valve II is of the two-position rotary type. The base 24 serves as the pipe bracket, and to it are connected pipes I8, I9 ,and 2l, The cap 25 carries the inverted seat for the rotary valve 26 which is turned by handle 21' through stem 2,8. As shown, there are two ports in the valve :seat each communicating with ra corresponding one of the pipes I9 and ZI. There is also an exhaust port 29 in the seat andan exhaust loop 30 and through port 3| in the valve `26. Pipe I8 is in communication with the chamber which houses the rotary valve.

The valve has two functional positions, running (Figure 2) in which it vents pipe I9 and connects pipe 2l to supply, and sanding (Fig- ,ure 3') in which it vents pipe 2I and connects pipe I3 to supply.

The bracket I5 has ports which simply form extensions of pipes I8, I9, 2I, 22 and 23 and hence can be identied merely by reference to the connected pipe. Most of these have extensions in the body of relay I6, and I9 and 2| have wexten- .sions into the body oftiming valve I.'|. These will Vbe similarly identified. There is also an atmosphere exhaust port 32.

The sanding relay valve and the cleanout `relay valvein body I6 are identical vand their identical components will-be identified Iby the same numerals distinguished by the letters s and c, so the two can be described together.

-The cleanout relay comprises two reversely 'seated poppet valves, a supply valve 3 3c and a vent valve-34e. Valve 33e is held in its normal closed -position by spring 35e and by supply pressure since the chamber 3Go is connected with pipe I8 (as is chamber 36s of the sanding relay valve). Vent valve 34e is normally open, and when closed its pilot engages the pilot of valve 33o rand holds the latter valve open. Chamber 3'lc between the valves is connected with cleanoutair pipe 23. The corresponding chamber'ls is connected with sanding air pipe 2 2.

The vent valve 34C is connected by bolt 38e v,and thrust plate 39o with the center of actuating diaphragm Mc whose margin is clamped by a cap 42e. The space ,43,0 above diaphragm AIC and the space 43s labove diaphragm 4Is are con- -nected with exhaust port 32. The space ,44e :below the diaphragm vIIIc is connected `by passage y.45 with the side ports 46 of the double check y out impulse, and the other operated when pressure is developed in pipe 2| to give the nal cleanout impulse. They deliver timed air surges to opposite ends of double check valve 41 so that each causes a timed surge in chamber 44C, and consequently causes timed cleanout flow through pipe 23.

The impulse unit connected with pipe I9 contains a diaphragm 5| interposed between a chamber 52 connected with pipe I9 and a closed volume 53 connected with chamber 52 by choke port 54. A spring 55 with thrustplate 55 urges diaphragm 5| toward valve seat 51 controlling flow to port 58 which leadsto the right end of double check valve 41. A choke port 59 affords a restricted atmospheric vent from port 58.

The other impulse unit is identical and parts are identified by the same reference numerals increased by |99.

Operation During running conditions, when sanding is not needed, manually operable Valve is in the position shown in Figure 2. Under these conditions pipe 9 is vented and pipe 2| is at supply pressure so that the chamber |53 is charged to supply pressure. Pressures on the diaphragm |5| being equal, the spring holds the diaphragm sealed against seat |51. At that time, pipe I9 and the chamber 53 are at atmospheric pressure, and similarly the diaphragm 5| is held against seat 51.

Assume now that the engineer shifts the handle 21 to sanding position establishing the conditions illustrated in Figure 3. This vents pipe 2| and charges pipe I9. The venting of pipe 2| has no immediate functional significance, but merely entails venting of chamber |53 to atmospheric pressure, the diaphragm |5| remaining seated against seat |51. But the development of pressure in pipe I9 does two things, it develops a pressure in the supply pressure chamber 44s as long as the valve remains in the position of Figure 3, and also it develops supply pressure in the chamber 52, with the result that diaphragm 5| moves to the right, since chamber 53 is initially at atmospheric pressure, and allows air to ow through port 58 against the right end of check valve 41.

The valve shiftsto the left and supply pressure is developed in chamber 44e. The supply of pressure persists only until equalization of pressures through choke 54 allows" Athe diaphragm 5| again to close against the seat 51.

When this happens the choke 59 will reduce the a pressure in the chamber 44e, at a rate dependent on the size of the choke.

The development of pressure in the chamber 44s develops sanding pressure in the pipe 22. So long as pressure persists in chamber 44o, cleanout flow occurs in the pipe 23. It is characteristic of the Campbell trap that if the sand hose is clogged, sand iiow will not start until the hose is blown clean, Sanding will continue as long as air is delivered through the pipe 22, that is, until the valve 29 is returned to the position of `Figure 2.

When this occurs pipe I9 is vented s o that chamber 44s is vented, and the supply valve 33s However, the concurrent development of pressure in pipe 2| will develop pressure in chamber |52. 'I'he chamber |53 having been vented to atmospheric pressure, the diaphragm |5| will move to the right and supply pressure will be delivered through the vvalve seat |51 and port |58 to the left-hand end of double check valve 41. Thus, another pressure impulse is developed in chamber 44o, and there is a final cleanout blast of air through the pipe 23. This blast will be of a few seconds duration, ending when choke |59 vents chamber 44e, after closure of diaphragm |5| against seat |51.

'I'he use of two impulse units in conjunction with the double check valve or its equivalent, affords simple means for delivering two independently timed impulses of cleanout air, one at the commencement of sanding, and the other at the termination of sanding.

While the duration of the impulse can itself have a timing effect on the cleanout blast, it is preferred to make the two impulse valves identical so that the impulses are of like duration. The timing of the cleanout blast is then controlled by determining the Venting action of the chokes 59 or |59, respectively. The function of the double seated check valve 41 is to select between the chokes 59 and 59. By using the check valve and two chokes of different capacity, it is possible to have an initial cleanout blast of one duration and a nal cleanout blast of different duration. Interchangeable chokes facilitate adjustment of the duration of each blast.

If difference of duration of the two cleanout blasts is not desired, the check valve 41 may be omitted. Omission of the valve 41 would place the ports 58, |58 and 45 in free communication with each other` In such case, the choke |59 can be replaced with a plug, as choke 59 would afford adequate venting.

It will be apparent therefore that the device is susceptible of considerable modification with minor resulting changes of operation. Such changes fall within the broad scope of the yinvention.

The arrangement illustrated is preferred for two reasons: It uses standard commercialcomponents, some of which are identical; it permits any necessary adjustment of the duration of each cleanout blast by the simple interchange of chokes.'

While the preferred embodiment has been i1- lustrated and described in considerable detail, it is intended to be illustrative and not limiting. The scope of the invention is described in the claims.

I claim:

1. A control valve mechanism for use with sanding traps of the type having a sanding air connection and a cleanout air connection, said mechanism comprising in combination, pressure operated means for supplying sanding air to the sanding connections; two impulse valve means each effective, upon the delivery of pressure fluid thereto, to deliver a fluid pressure impulse to the cleanout connection; and a sanding control valve having a sanding position in which it supplies air under pressure to said pressure operated means and to one of said impulse valve means, and a running position in which it vents said pressure operated means and delivers air under pressure to the other of said impulse valve means.

2. A control Valve mechanism for use with sanding traps of the type havingasanding air connection and a cleanout air connection, said mechanism comprising in combination, pressure operated means for supplying sanding air to the sanding connection; two distinct impulse valves each arranged to delivera fluid pressure impulse upon the delivery of fluid pressure thereto; connections comprising check valve means and vent chokes rendered effective selectively by the im`` pulse valves whereby each impulse valve may deliver a characteristically timed cleanout impulse; rand a sanding control valve having a,v sanding position in which it supplies air under pressure to said'pre'ssure operated meansk and to one of said impulse valves, and a running position in which it vents said pressure operated means and delivers air under pressure to the other of said impulse valves.

3. A control valve mechanism for use with sanding traps of the type having a sanding air connection and a cleanout air connection, said mechanism comprising in combination, a pres'- sure motor actuated relay valve operable to deliver air under pressure rto said sanding connecnecton and: when inactive serving to vent said connection; a pressure motor actuated relay valve operable to deliver air under pressure to said cleanout connection and when inactive serving to vent said connection; two impulse valves eachadapted to deliver avtimed pressure impulse in response to the development of pressure thereupon; a pair of vent chokes; connections includi ing a double-seated check valve for directing impulses from whichever impulse valve is active to the 'motor of said cleanout relay and for connecting a corresponding one of said vent chokes with suchmotor; and a sanding control valve having a sanding position in which it develops pressure in the motor of the sanding relay and develops pressure upon one of said impulse valves, and a tion; a pressure motor actuated relay valve operable to deliver air under pressureto said cleani out connection; two impulse valves each adapted to deliver a timed pressure impulse in response to the development of pressure thereupon; a pair of vent chokes; connections comprising check valve means for connecting an active impulse valve and a corresponding one of said vent chokes with the motor of said cleanout relay; and a sanding control valve having asanding position lin which it develops pressure in the.

motor of the sanding' relay and develops pressure on one of said impulse valves, and a running deliver air under pressure to said vsanding con- 'running position in which it vents said motor and develops pressure on the other of said impulse valves. v

5. A control valve mechanism for use with sanding traps of the type having a sanding air connection and a cleanout air connection, said mechanismcomp-rising in combination, pressure operated means for supplying sanding air to the sanding connection; a second pressure operated means` for supplying cleanout air to the cleanout connection; two distinct impulse valves each arranged, upon the supply of air under pressure thereto, to deliver a iiuid pressure impulse to said second pressure operated means; and a sanding control valve having a sanding position in which it supplies air under pressure to the first named pressure operated means, and to one of said impulse Valves; and a running position in which it vents said first named rpressure operated means and supplies air under pressure to the other of said impulse valves.

HENRY NORTON SUDDUTH.

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