US2358644A - Self-lapping valve device - Google Patents

Description

P 1944. c. s. KELLEY SELF-LAPPING VALVE DEVICE -INVENTOR Ce oil .SKeu, e3 B ATTORNEY Filed May 27, 1943 I from .the following the invention.

Patented Sept. 19, 1944 1;,,UNITED STATES PATENT SELF-LAPPING VALVE DEVICE Cecil S. Kelley, Forest Hills, Pa., assignor to The Westinghouse Air Brake Company, Wilmer ding, Pa., a eorporatio n of Pennsylvania 1 V f V Application May 27, 1943, Serial No.'4 88,665

" 5 Claims; ('01. 303 -54) invention relates tofluid pressure control devices and more particularly to the automatic orlself-lapping type. a r 4 One-object oftheinvention is the provision -of--an improved device of the above type.

Another object of the invention is the provision of a devicegoftheabove type in which the movableparts have relatively low frictional resistance to movement whereby the device is rendered very-sensitive to slight changes in controlling force and is therefore operative to vary .the pressure of fluid with a relatively high degree of accuracy in accordance with the degree of such force and slight changes therein.

- 'Another object of the inventionis the provision of a device of the above type embodying means 'for substantially counteracting pressure of fluid supplied by the device so that the controlling force for the device is substantially in- ;dependent of or not materially influenced by ;said pressure of fluid. w c Other objects andadvantages will be apparent more detailed description of -In.the-accompanying. drawing: Fig.v l is a vertical sectional .view -of the improved control device; Fig. 2 isa sectional view of a portion of saiddevice taken on the line 2 2 in Fig. 1; and liig. .3 is-.asectional view taken on the line 33 .in Fig.2, iv v 1 V I 'lllescription As shown the drawing, the improved'con- .trol device comprises a casing section I having a chamber Z-eXtending .therethrough from one v end to'the opposite end,-a flexible diaphragm 3 is mounted overone;,end of chamber 2 and is clamped around-its marginal edge between the end creasin section; I and a cover 4 secured theretoXAn oppositely disposed and coaxially arranged diaphragm. 5 is mounted over the oppositeend. ofv chamber 2 and clamped in posi- ;tion ,aroundits marginal edge between the end "of the casingsection. I and a cover member 6 .securedtow the casing section. The two diaphragins are preferably-of substantially the same area and .bothare subject on vtheir adjacent faces to pressure inchamber' 2jwhich isopen to the atmosphere inv a manner which will' be later broughtout. At the opposite side of diaphragm -is a pressure chamber 1 which is in permanent communication byway of a passage 8 extending 7 through the' casing section I with a chamber 9 6 provided betweenthe; Opposite side of diaphragm '5 and the cover member 6.

v the wall I! within the'bore is of the free sliding type in' order'that said portion may substantially freely reciprocate therein. The member l2 has a bore [9 open at oneend to bore l and at the" opposite end through a; valve seat to a chamber 2| whichis open to chamber l8. A release va1ve22 disposed in chamber l8 has a flutedstem'23 which is' disposed to slide in bore :IBiand said valve is arranged to cooperate with the valve seat Zll for controlling communication between chamber 18 and the atmosphere by way-of bores I 9 and |5and other communication to be later described. Chambers 9 and [8 are in constant communication with each other through a stabilizing choke 5l.-

A fluid pressure supply valve '24 is contained in a chamber formed below chamber l8. 7 This valve is-arrangedin coaxial relation with and to seat in the same direction as the release valve 22 and has a fluted stem 26 extending through, a bore in a wall separating chambers l8 and 25, and engaging'the release valve 22 in .chamer 2|. The supply valve 24 is providedfor controlling communication between chambers 25 and I 8,-and a springv 2Lcontained in chamber 25 acts on the supply valve for urging it to its closed position shown.

Two followers 28 and 29 are clamped centrally Y to opposite sides of. the diaphragm 3 by a nut 30 engaging the follower 28 and having screwthreaded engagement witha stud 3| projecting from the follower 29 centrally through the dia phragm andthe'follower 28.

The follower 29 is disposed in chamber 2and has a stem .32 extending into said chamber. The follower!!! secured. to the adjacent sideof. diaphragm 5 has a stem33 having telescopicengagement with stem 32 within a bore 34 which, 1 V

above the end of stem 33, is opento'chamber 2. through ;a.,passage 35. The stem 33 has a bore 36 open at one end to bore and .at the opposite to a larger bore 3'! which opens to bore l5,'these bores and, passage 35 constituting the communication'for conducting fluid released oFFicE l1 and acts against flange I3 of member l2 with I a relatively small force for urging said member and diaphragm l2 in the the release valve 22.

A coil control spring 39 'encirclesfthetelescoped portions of the two stems 32 and 33 and has one end supported on the, diaphragm -follower l while the opposite end bears against 2,358,644 s: l r,"

direction away from an annular collar 40 provided on stem '32; It

will be se'enrt-hat this spring constitutes a resilient strut :between the two diaphragms. In the position of the diaphragms shown in the drawing in which the re ease. valve '22 is open,

the spring 39 -is substantiallysfully expanded.

The casin'g'section; l isprovided with a pair vof spaced lugs 4| at either side of an opening 42 connecting chamber, 2 with the atmosphere. operating lever 43c-extendsthrough this opening into chamber- :2 and-is fulcrumed on a pin 44 disposed at right angles to the axis of stem'32 and carriediby the lugs 4 l." The stem 32 is provided with a slot '45 extending diametrically therethrough, and theend of'lever 43 in chamber- 2 isdisposeduinrthis slotin sliding contact 'with' the opposite 'ends-"thereof;"the surfaces of 'thellever engaging th'een'd' walls of the slot being roundeditofacilitateTmovement "of'the end of fthe lever' within the slot upon rocking of said I lever about the 'fulcrum'pin'i '44.." The por'tion-" of lever''43 outside for the casing se'ction constitutes f a control portion which may operated 'in'any'desired mann'er, as-by hand; i

' For reasons which will be hereinaiter brought out, it' is desirable w stabilize the lever 43' against unwantedfmovement. This may bef a'ccomplished'byway of illustration by use of a friction shoe in 'th iormvof a disic 46 which is slidthe "fingers 4 1 "andf4'8 bears at opposite ends against the =lever i4f3and Irictionshoe 46, respectively. This spring is underpressure .and com;

stantl'y acting to press thefshoe 46 into fric- "tio'nal contact with the inner, surface of one lug 4l and at the same time, .acting tov press :the

pp e li i jq ii he mama P lever 43into frictionahjcontactwith the inner surface'pffthe otherflugilywhereby a definite, fric- "tional resistanceto movement of the lever 'is chambr jzs i" hanged to be ja s alya plied with" fliiidiunder' pressure from any suitablesourceiby way ofla pipe,,52., Chamber i8 is connected to ajpipej53 whichlmay lead to any ide surface of I the l device "(notshowrb which-. it is desired ,Lto con-,

trial by fluid under pressure.

pally flows" through cli oke fphragm chambers "restrict such flow to a 33, on the diaphragm l0 stops movement Operation the connected chambers Qfand 1 are open to the atmosphere past the release valve 22 to chamber 2 and thence throughopening 42 in the casing section'l.

I-f -it-is now desired to supply fluid under pressureto pipe 53,- the lever 43 is rocked in a counterclockwise direction which moves the stem 32 and connected portion of diaphragm 3 in a downwardly direction and this movement is transmitted through collar 40 on said stem and spring 39 to follower l0 and deflects the diaphragm 5 in a downwardly direction. It should be noted that spring 39 merely acts, in 'efiect, like a solid "strut between 'stem 32 and diaphragm 5 in the movement just described, but that such movement is opposed by the force of bias spring 5!! which, however being relatively small, is i'r'rmiate'ri al. i v The spring 2! actson 'the s'upply valve '24 with greater force than the pressure of spring '38on the; release valve" 2 2,"s'o as'to hold said valves in the position shown during the downward, movement of" the diaphragms; above ee- ,scribed,until' the member l'2 secured to diaphragm 5 seats against-the release valvei 22. Further downward movementbf the diaphragm by continuedmocking of "lever 43 in a counterclockwisedijrebtibn then acts through the re- 'leasevalvei 2 2" and su pply va1ve stem '26 to unseat the supply valveflj against spring 21;

I vWhen the supply valve 24' 'i rthus' opened, 'fluid under pi-essurethen flows from chamber 25 past said valve to chamber 8 and pipe 53, and from chamber l BIfluid 'under pressure also grad- 5linto chamber 9 at the lower side of diaphragm a'and thence throu'gh passage! to ch'amber l at the opposite to prevent a surge of fluid pressure into the dia- Qandl, or in other words, to

degree which provides for an increase in pressure in said chambers substantially with the-increase, in pressure in the device being controlled and supplied fluid under pressure through pipe53, 7

When. the pressure'of fluid thus obtained in chamber 9 and acting on the diaphragm 5 in conjunction ,withfspring' 5 0 lis in-creased to a degree which 'overcomes'th'e 'force of spring 39,

said diaphragm moves'upwardly' relative to lever [43 and allows spring 121 to movethe supply valve "24 toward its seat, movement continues as the pressure of fluid in chamber 9 continues to increaselfby the supply-past the supply valve 24 until said valve jmoves into contact with its seat which thenfprevents further flow of fluid to pipe'BS'and thus to chamber" 9 and thereby limits the pressure' of fluid obtained thereinto 'a' degree predetermined by the extent of counterclockwisemovement of lever 43 from its noti pos showninth f r wi w en the V supplyvalve 24 closes 'tg limit the pressure of uidin pipe 53 and chamber 9the force oispring thereof :sothatthe release valve, 22 remains seated there- "by bottling up the ul .p-rs l e inp p 5 n chamber 8, I V

in pipe 53, the lever 43 is moved further in, a

counterclockwise direction, [and this a movement is transferred through spring39 to again deflect diaphragm downwardly to unseat the supply valve 24. Fluid under pressure then again flows to pipe 53 and diaphragm chambers 9 and Ijand when the pressure of fluid obtained in said chambers'and acting on diaphragm 5 is increased to a degreecorresponding to the position of lever 43, the diaphragm5 again assumes the position to permit closing of the supply valve 24 while maintaining the release valve 22 closed. If it is now desired to' reduce the pressure of fluid in pipe 53, the lever 43' is turned in a clockwise direction back toward its normal position shown in the drawing. This movement draws the stem 32 in a'direction away from the release valve" 22 which permits pressure of fluid in chamber 9. acting on diaphragm5 to, deflect said diaphragm'and move spring 39 along with the stem 3 2. deflection ojfdiaphragm 5 moves the member l2 out of seating engagement with the release valve 22, whereupon fluid under pressure is allowed' to, flow from-pipe 53 to the atmosphere past said valve. Fluid under pressure in chambers 9and reduces through choke 5| as the pressure of fluid in pipe 53 reduces and the pressure of spring 39 then deflects the diaphragm 5 relative to lever 43 back in the direction of the release valve 22. Assuming that lever 43 has not been returned to its normal position which permits full expansion offspring. 39 with the release valve 22 open, the diaphragm 5 will therefore be deflected .to the position closing saidvalve, when the pressure of fluid in pipe 53 and in chambers 9 and 1 becomes reduced to the degree determined by the reduced pressure of spring 59 as predeterminedby the position of lever 43. If-the lever 43 is moved further in the direction of its normal position a further and corresponding reduction-in pressure of fluid in pipe 53 will occur in thesame manner as just described. In case-the lever 43 is returned to itsnormal position which allows full expansion of vspring 39, the pressure of fluid in chamber 9 'will' deflect the diaphragm 5 to the position shown, and in which it will then remain to allow a full release of fluid under 53 and chambers l8, Sand 1. The bias spring 50 is provided ,to ensure that the release valve 22-wi1lbe opep when the pressure of fluid in chamber 9 is at a very low degree withr'espect to atmospheric pressure so as to ensure a complete release of fluid under pressure from pipe 53; sired this spring could be dispensed with.

In the operation above described it will be noted that the only friction which tends to interfere with"operation" of the device to provide fluidyat a pressure :inaccordance with chosen.

positions of the lever 43, is that between the depending portion l5 of the member I2 and the casing wall 11, and between the stems 23 and 250i the valves and the walls of the bores in which they operate and since this'friction under all normal conditions will be of a relatively low degree, the improved device is capable of providing'with a relatively great degree of accuracy fluid at different pressures chosen by the position of lever 43. Moreover, and for the same reason, the structureis very sensitive to slight changes in position of lever 43 as reflected by slight changes in pressure of control spring 39 pressure from pipe The parts might-be so arranged that if de increments of changein' pressu're in pipe 53;

As above mentioned, when fluid under pressure is supplied through choke'5|"to"chamber'9 to act on diaphragm" 5, it also flowsto' chamber I and therein acts on diaphragm'3. Also when fluid under pressure is'released from pipe 53 and thus from chamber9 a corresponding reduction in pressure occurs in chamber 1. It will therefore be seen that diaphragm '3' is always subject in chamber] to the same'pressure of fluid as'iseifective in chamber 9 on'diaphragrn 5, and it will also b'e'noted that such pressure acting on the two diaphragms is appliedin' op-' posing relation to the opposite ends 'of the spring 39. .Now assuming that the pressure of fluid acting on the diaphragm 3 would provide a force on stem 3'2 and thus on the connected end of spring 39 substantially equal to that provided on the opposite end of said'spring by pressure of-fluid in chamber 9 acting on the diaphragm 5, it will be seen that suchfpr'essure on diaphragm '3 would counteract that on diaphragm 5 so that none of the force of "said spring would be efiective to oppose movement'of'lever' 43. Thus re gardless of the position of lever 43 it couldbe moved out of such position with substantially the same degree of ease 'orforce as resists the initial movement thereof out of its normal position.

be obtained in a practical structure throughout the full range of fluidpressures which maybe supplied by the device,f.due to the change in position of diaphragm 3 for each different pressure, it being noted that the position of said diaphragm and thus the pressure provided by same on stem 32 will vary according to the position of lever. 43, while the position of diaphragm '5 for any selected pressure in pipe 53 is always the same. vThus while a complete counter-balancing of forces is possible of attainment say in one position of lever 43, it may notbe. attainable in the other positions of said lever. In these other positions of the lever, alsmall'portion of the force of spring 39 may therefore be transferred to the leverwhich would tend; to turn same out of a selected position or oppose movement to a different position. The amount of force thus, transmitted from the spring 39 to the lever 43 will however be of a relatively small degree and will, not ,materially interfere with the ease of operation thereof. r

The friction between lever 43, shoe 46 and lugs 4| will hold said lever against being turned by any portion of the force of spring 39 applied to said lever, as just described. This friction is also intended to hold the diaphragm 3 against undesired deflection out of any selected position to which it may be moved by the lever 43, under condit ons such as the following:

If for instance the friction between sleeve-like portion l6 of member l2 and the casing wall l1 should become abnormal, this would require a greater pressure of fluid on diaphragm 5 to effect closing of the supply valve 24 than might be required to deflect diaphragm 3, as a result of which, if diaphragm 3 were not held against movement, it might deflect according to the increase in pressure of fluid supplied to pipe 43 and correspondingly increase the pressure of said spring on diaphragm 5 and thus prevent obtaining a suflicient differential of forces on diaand is thus capable of providing relatively small A complete counter-balancing by diaphragm 3 of pressure of fluid on diaphragm 5 may not 7 phragm 5 to efiect-closingof the supply valve. In other words, regardless of the position to which lever .43- was moved out of normal position, the supply valve might be maintained open and provide the maximum pressure of fluid in the pipe 53. Moreover, such abnormal friction could result in a complete release of fluid under pressure from pipe 53 when such was not desired. Still further, assuming the frictional condition of the parts'to be normal and the opposing forces applied. by diaphragms 3 and 5 to the opposite ends of spring 39 to be equal or; nearly so, a sudden jarapplied to the casing, would tend to move samerelative to the diaphragms and the connected followers, stems and spring 39. This jar applied in one direction would tend to cause deflection of the diaphragms such as to cause opening of the supply valve 24 andthereby undesired flow of fluid under pressure to pipe 53. Applied in the opposite direction the jar would tend to cause deflection of the diaphragms to cause opening of the release valve 22 and thus an undesired release of fluid under pressure from pipe 53 in case said pipe were supplied with fluid under pressure at this time. These objectionable operations however are prevented by holding the lever 43 and thereby diaphragm 3 against unwanted movement as by the friction between said lever and shoe 46 and the casing lugs 4|.

Summary i It will nowIbe noted that I have provided a self-lapping valve device so constructed as to minimize the effect of friction between parts on its .operation, so that the device may, respond to any selected control operation to provide with accuracy fluid at a desired pressure. The device embodies a control spring and means for counteracting the force of said spring so that the operation of the control member may be substantially independent of the force of the control spring and thus operative with substantially the same degree of ease for all pressures of fluid suppliedby the device. Due to the sensitiveness of the structure to slight changes in actuating force provided by pressures of. fluid acting thereon means in the form offriction means associated withthe control port have been provided to ensure stability of the device under certain abnormal conditions and which means in no way interferes with the sensitivity of the structure and with the accuracy with which it willoperate.

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

1. In combination, a casing, two movable abutments in said casing, means connecting one of said abutments to the other comprising resilient pressure exerting means, said abutments being subject to pressure of fluid in a chamber which opposes pressure of said exerting means, valve means controlled by one of said abutments for controlling pressure of fluid in said chamber, said one abutment being operable by said exerting means upon movement thereof in one direction to effect operation of said valve means to supply fluid under pressure to said chamber and upon movement in the opposite direction to effect operation of said valve means to release fluid under pressure from said chamber, a rockable member having a fulcrum connection with said casing and movable relative to said casing to effect movement of said exerting means, said member having frictional contact with said casing,

a friction member movable-with said rockable member and alsohavingfrictional contact with said casing, and spring means urging "said rocks able member and friction member against said casing to provide a chosen force'for resisting movement of saidrockable member. 1:

2. In combination, a casing, two ,coaxially aligned and spaced apart movable abutments in said casing subject on opposite sides to pressure of fluid in a chamber, follower means associated with one of. said abutmentsjhaving' an opening for releasing fluid under pressure from said chamber, a release valve in said casing arranged to cooperate with said follower meansupon a certain movementof said one. abutment in a direction against pressure of fluid in said chamber to close communication between said chamber and opening, a supply valve operable by said release valve upon greater movement fofsaid one abutment in said direction to supply fluid under pres sure to said chamber, said oneabutment being operable upon movement in the opposite, direction to. effect closure'of said supply valve and then opening of said release valve, means connecting said abutments to each other comprising a spring, and a member associated with said casing and connected to 'said one abutment through said spring and operable upon move ment inone direction to actuate said spring to move said one abutment in the direction against pressure of fluid in said chamber and operable upon movement in the opposite direction to render said one abutment movable by pressure of fluid in said chamber. i i

3. In combination, a casing, two coaxially aligned movable abutments in said casing subject on opposite sides to pressure of fluid in a chamber, two telescopically arranged members disposed between said abutments for movement axiallS thereof, means connecting oneof said members for movement with one of said abutments, means connecting the other member'for movement with the other abutment, a springinterposed between and connecting one of said abutments to the said member connected to theother abutment, control means connected to the last named member operable upon movement in a direction against said spring to move said one abutment in the direction against pressure of fluid in said chamber and operable upon movement in the opposite direction to render said one abutment movable therewith by pressure of fluid in said chamber, and valve means con trolled by said one abutment and operable thereby upon movement in the direction aganist pressure of fluid in said chamber to supply fluid under pressure to said chamber'and in the opposite direction to release fluid under pressure from said chamber. v

14. In combination, a. casing, two coaxially aligned movable abutments in said casing subject on opposite sides. to-pressure of ,fluid in a chamber, two telescopically arranged members disposed between said abutments for movement axially thereof, means connecting one-of said members for movement with one of said abutments, means connecting the other member for movement with the other abutment, a Spring interposed between and connecting one of said abutments to the said member connected to the other abutment, control means connected to the last named member operable upon movement in a direction against said spring to move said one abutment-in the dierection against pressure of fluid in said chamber and operable upon movement in the oppostie direction to render said one abutment moveable therewith by pressure of fluid in said chamber, said members and the said means connecting said one abutment to the respective said member cooperating to provide a communication for releasing fluid under pressure from said chamber, and valve means including the last named means controlled by said one abutment and operablethereby upon a certain movement in the direction against pressure of fluid in said casing to close said communication and upon further movement to supply fluid under pressure to said chamber and operable upon a certain movement of said one abutment in the opposite direction to cut off the supply of fluid under pressure to said chamher and upon further movement to open said I from said chamber, a poppet type release valve arranged to cooperate with said sleeve-like portion to close said release communication upon a certain movement of said one diaphragm from a normal position in the direction against pressure of fluid in said chamber, a supply valve arranged to be opened by said release valve upon further movement of said one diaphragm against pressure of fluid in said chamber, to supply fluid under pressure tosaid chamber, means operative to close said supply valve upon movement of said one diaphragm in the opposite direction and said one diaphragm being operative upon return to said normal position to move said sleevelike portion out of cooperative relation with said release valve to open said communication, and means for controlling'movement of said one diar phragm comprising a spring operatively connected at opposite ends to the two diaphragms, and a control member connected to the end of said spring which is connected with the other diaphragm and operative to vary the position of the connected end of said spring relative to the position of said one diaphragm.

CECIL S. KELLEY.

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