Патент USA US2404512код для вставки
July 23, 1946. H, (3, MAY ErAL 2,404,512 CONTROL APPARATUS Filed April 29, 1944 mvguroxs Harry G May‘ ' Glenn TMcG’l‘upe BY ‘ Q, 2 ‘ . ATTORNEY _ 2,404,512‘ PatentedvJuly 23, 1946 UNITED STATES I ..2;.404,512 PATENT fOFiFfliCi‘E V CONTROL APPARATUS ' ‘Harry McClure,May, McKeesport, East McKeesport, Pa, assignors ‘and -1Glerm to 'il‘he =Westinghouse-Air 'Brake Company, :Wilmerding, ¢Pa‘.,' a corporation of Pennsylvania Application fApl‘il‘ZQ, 194:4, Serial‘Nof533A27 6 Claims. (Cl.121--;4-1)> “1 sure. ' One ‘object of 'the‘linvention is the ‘provision of an improved control apparatus “of the "above type. Another object "of the ; invention ‘is ‘the provi ‘sioniio'f "a control apparatus embodying a fluid pressure control-led supply and release ‘valve mechanism so constructed'and arranged that the pressure of E?uid provid'ediby‘said mechanism has - ~ A supply and ‘release valve zstlfll?tlll'?rl? is provided for regulating :pressure- of :fluid impres sure chamber 2 to control thet‘positioning 103:‘ the power ~vpiston I‘ 'in- accordance :with :pressure of operated ‘power means “for selectively positioning a‘mul-ti-‘position device ‘to be operated,‘ such as anieng'ine throttle, aclutchyetc; 2 said vchamber “is substantially atmospheric ~pres~ ' vThis invention relates "to ‘control apparatus and more iparticularly 9to the itype \rem'bodying Tluid ' controlling filui'd provided through acontrolpipe lI-I to :act 2in‘a chaniiber t2 ion .21, 2pilot diaphragm ‘l3. - The control" pipe EH qnayhe connec‘tedl‘to any 1.0 suitable operatorisboritrol'wdearice Knot shown) locatediat any Pfdes'i're‘d station and which is jop erative to ‘provide any “selected pressure :of :?uid in chain-her ' 42 ifrom atmospheric pressure -'to :a no‘ effect upon ‘the operation of the ' apparatus ‘in chosen rrnaximum degree in ‘excess of *ithatrof the respon'sei'to‘the"controlling ?uid. ‘ Still another object "of the invention ‘is "the provision for a "relatively simple control apparatus arranged ‘for :control ‘pneumatically "from ‘any atmosphere. ’ a ' "Theisupply and "release 1valve structure "t0 com operate with promptness ‘to ‘position 'a'dev'i'ce‘be prises "a bushing or- nsleeve ‘J15 pressed ‘into :a bore in the casing in parallel relation to but spaced vfrom the piston rod One-end of this tbu-shing of a'controlling "fluid, and regardless of the pres to atmosphere ‘through a v"breather port H. The suitable control *station ' and "which ’is adapted to ing controlled "in " accordance with the “pressure 420 qpmposiitehendl-extends- outsidev of the casing “in-i-the sure :of ‘fluid required to-‘position ‘said device. same 1direct'ion-?as'fpiston rod .‘Other "objects ‘and advantages will ‘ be apparent ‘. In the accompanying drawing, the single :?g ure'isi'a diagrammatic sectional view of a control apparatus embodying the‘invention. while within the l. casing, the "bushing ‘sis eiic'ircledFby an annular recess 18 fwhich-“openslto a cavity 1P9; Pressure chamber -’2 "is ‘also ‘open ---to --ca.vi-ty 19 through ‘a fromithe "followingv’m'ore detailed description of the ‘invention. terminaitesin a cchaniberl?iwhich mayibeeopen passage'?. ‘ v i . " —A-p'1unger 12! i'containe’d »'mainly in chamber IIEB ‘ ‘has one "end mounted tois'lidei'ini-the adjacent end Description portion‘ro‘f/ sleeve T l5 , ‘while ‘ancoppos'itely arranged ‘ plunger 22 also slidably mounted 1‘in said bush As ‘shown in the drawing, the tim‘provedfcon ing projectsetrom "the opposite end of bushing l1 5. Within the v's‘leeve 1'5 fthesplunger2l has Van‘ Van nular recess containing arsea'l ‘ring 23‘ having trol apparatus ‘comprises ‘a *casing ‘containing ‘a power piston ‘I ‘having ‘at ‘one "side ;a "pressure chaniber '2 ' 'and‘havinga't the opposite ‘side ' a .non sealing #contact “with said plunger iandithe ‘inner wall ‘of ‘said sleeve to prevent '~'leaka‘ge ~o‘f ?uid pressurechambert. "Theouterend, of the non pressure chamber closed .iby "an integrally formed ‘head ‘4 having "a ‘central opening lined with *a"bu'shing~5.' VA piston'rodilifhaving one’ end under ‘pressure 1from ‘a chamber ’-24 ‘formed be tween ‘the adjacent ends of‘the =two - plungers to chamber 116. similar 'seal ring '25 ‘is ‘provided secured "tothecen'teriof piston l extends through thenon-pressure cham'her '3_ 'andfbus'hing ‘5 "to the 40 in'theadjacent‘end o‘f‘ plunger 22 to prevent leak- ' age 70f Tluid‘under pressure ‘from chamber 1'24 past exterior .of thecas’ing. "Outside o'fthe casing the said ‘plunger. to atmosphere. Chamber 24 gislcon rod‘6 is adapted to ‘be connected to a device (not stantly ‘open through one" ,or more ports ‘26 in shown) whichlit is .idesire'dr'to operate. .Su‘f?cient bushing 4-5 to recess '18 and thus “to pressure clearance may exist around the rod 6 ,in bushing 5 'to allow breathing of the non-pressure cham ber 3 to. and from. atmosphere. ' Theinon-pressure chamber 3 contains a coil control spring "'I encircling the-piston rod '6 with 4,5 chamber2. . "I'he'plunger *2l ‘has a‘*bore;or chamber ‘21 ar ranged to hecbnstantlygsupplied'with‘?uid ‘under one end ‘supported on ‘the non-pressure "head '4, pressure ‘from any (suitable vsource. One struc ture ‘for thus conveying ?uid’to bore 21 consists, This spring is under’ a sufficient degree of ‘pres sure to urge the piston * l-itoithe ‘po‘s'ition‘r'in which coaxial ‘but "reversed relation to and “spaced ~from while ‘the opposite "end "bears against ‘piston *1. 50 as~shown‘in “the drawingyof‘a ?exible diaphragm it isshown‘in‘th'e drawing, which/position ‘isde 28 ‘of the same “area as - diaphragm ‘ vl3-arranged in the ‘ “diaphragm "l3, -=iboth vdiaphragms being clamped ito‘theca's-ing around ‘their ;outer pe 8 - in'lpressure ' chamber 52, ‘when the pressure Vin 55 ripheral edges :in xaiconventional-»-manner. ‘Be termi-rred by contact of 2piston ‘rod 16 withia- stop 2,404,512 a 3 e ' I 11,? 4 V tween the two ‘diaphragms is formed a pressure chamber 29 to which is connected a ?uid pres sure. supply pipe 30a leading from the source of ?uid under pressure. Diaphragm 28 has at its opposite side the chamber H2‘. The plunger 2| has a followerjplate 30 in lower 54 and the release valve stem 46 so as to be constantly eifective to urge the plunger 22 in a direction out of seating-contact with the release valve 45. The spring 53 is weaker than spring 42 for reasons which will be later brought out. A spring seat 55 is secured to plunger 22 outside chamber l Hi‘ engaging ,the adjacent face-ofzdi aphragm 28, andiextending from this follower and is engaged by one-end of a coil spring 51 ofithecasing' by any suitablesecuring'means 56 plate through the two diaphragms and a follower plate 3| engaging and connecting the adjacent encircling the portion of sleeve l5 projecting from the casing, and the opposite end of said spring faces of the two diaphragms is a projection, 32. , of plunger 2| . This projection extends into is supported on the portion of the casing en circling said sleeve. The spring 5’! exerts a rela chamber |2 slightly ‘beyond the outer face of’ di ' tively small degree of force on plunger 22 urging aphragm i3, and within this chamberfa follower plate engages the'adjacent face of diaphragm I3.‘ same in a direction toward the right hand. An ‘adjusting screw 58>is'mounted in the outermost endof plunger 22 and is secured in' an adjusted cThe' projection 32 is‘ providedwith a screw threaded bore 34,-and a nut 35 having screw position by a lock nut 59. The casing is provided with a projecting bracket plate 33 is mounted on this projection which threaded engagement within this bore is ‘provided B0 in the outer end of which is a fulcrum pin 6|. with a ?ange 36 which engages the plate 33. 20 A follower-up member 62 mounted to rock on Tightening‘of' nut 35 clamps ‘the ‘central portion of diaphragm ‘l3 between the follower plates this-pin has an operating-arm 63 ‘in the end of which isa slot through which extends a ping-:64 secured to thepower piston rod 5, whereby said arm‘ will be moved with saidpiston._ The follow 33 and‘3l and at the same time clamps, the cenee tral portion of diaphragmr-28'between plates 3|‘ and 38,'as will be apparent. 1 25 up member 62 also comprises a cam 65,-’ theper v It willbeseenthat' the effect of pressure of ?uid from the source in chamber 29.011 diaphragm‘ ipherial surface of which is aligned with the axis of the adjusting screw 58. lAnarm, B6 fulcrumed ‘ I l3 will be offset by its. effect on diaphragm 28 ' at one end on a- pin ?‘l'secured inbracket 60 has ‘and will therefore. not'in?uence in» any way pres ' sure of. controlling-?uidin chamber I2. at its opposite end a vcylindrical like enlargement The screw-threaded ‘bore 34 inthe projection 32 v'ofaplunger 2|~_is;: open to bore .21 and'also through one 'or more, ports 38 in said projection and :ports'i39iin‘vfollowerl plate 3| to chamber 29,‘ whereby bore 21 will be constantly supplied with 1 ?uid under-“pressure from the supply pipe‘ 30aj when said ‘pipe is‘ supplied with ?uid under pres sure. ,7.“ _ . , _ 68 interposed betweenhand engaging on one side the’ adjusting screw 58 while itsoppositeside engages the peripherial surface of cam 65. -The surface of cam 65 is so formed as to permit move; ment of plunger 22 in the direction of said cam upon rocking of the follower~up member 62; in a counterclockwise direction, and to-displace said vplunger into sleeve |5 upon rocking ofthe follow _ up member in the opposite direction.‘ _ v V The bore 21 contains a ?uid pressure supply In chamber I6 is a control spring 10 encircling 'valve lid-having a‘ ?uted stem 4| having sliding 40 the plunger 2|. One end of this spring is sup contactwith-the side wall .of a bore which is of ported on the portion of the casing encircling the smaller diameter thanvthat of bore 21 andwhich,‘ end of bushing |5 which extends into said cham at the'end of plunger 2|, opens into chamber 24. ber, while the opposite end of said spring bears Atthe junction of-these two bores is a seat forv against a follower 1| slidably mounted on said the supply valv'e'4D; One end of a coil spring 42 plunger and ' arranged to contact the follower contained in'chamber 21 zbears‘against the supply v Valve 40 while the opposite end is supported on‘ The spring ‘H1 is arranged to ‘urge the ‘dia plate 30.‘ a perforated seat 43projectinginto said bore-from . V a v _ . phragms I3, 28 ‘and plunger 2| in the direction .of the nut-35., This spring is under pressure and the left hand only to the positions shown in the therefore constantly eifectivewto urge the supply 50 drawing and to oppose with increasing force’ 3 ' valve toward "its ,seat. ‘;'-~ In chamber 24,~the;end of the supply valve stem 4| engages a ?uid pressure release valve 45 con, tained, in-said'chamber and having a ?uted stem “which, is disposed to'slide in an axial bore pro vided in the plunger 22, saidstem‘ “extending j ; through said bore. and into a bore 41 of larger diameter.-¥The plunger 22 is provided on its end movement vof these parts from said positions in the direction of the right hand. The diaphragms I3, 28, and plunger 2| are. also movable from “the positions shown in the drawingtoward the left hand relative to the control spring 15 and plunger 22 to positions de?ned by contact of nut '35 with a stop shoulder 12. The action of springr53ron 3 tween said chamber and bore 41 whichlbore is in ~ the ‘release valve stem 46, transmittedthrough the two valves 45 and40 and the stronger spring 42 to nut 35 is adapted to e?ect movement of the parts to this latter position’d’e?ned by Contact ‘ constant communication with they atmosphere , , between nut 35 andstop 12, and it "willb'e noted through one or more ports 48,’ an annularrrecess ‘ 49 in the outer peripheraljsurface of plunger 2|" that such movement will unseat the release valve 45 from the end ofplunger 22 while the supply 7 in chamber 24 with a seat for cooperation with 1 the vrelease valve to control communicationbe to ‘ and one or more ports 50 in sleeve'l5. V 7‘ vIn'bore;4'| the release valve stem ‘46 engages one side ofaspring seat 5| which is‘loosely ‘ ; ‘mounted in said bore'and which maybe provided ‘ ‘ i ; with one or more notches 52 around its peripherial edge to allow ?ow of ?uid under pressure from one side tothe opposite side. ,The opposite side of springseat 5| is engaged by one end of a coil ‘ 1 spring 53, theopposite end of which is supported 3 by a follower 54 secured ‘in plunger 22. The spring 53 is con?ned underpressure between £01: ' valve 40 will remain, seated under pressure of the stronger spring 42. j r _ , 1 The nut 35 has an extension the end of ‘which constitutes a plunger 73 which is disposed to slide in a bushing '14 in the casing. The plunger, '53 has an annular recess in which is disposed a sealring 15 having sealing contact with the plunger and bushing to prevent leakage of ?uid under pressure between chamber I2 and a pressure chamber 76' provided at the outer end of the plunger. Cham ber 16 is open through a passage 11 to cavityi I79 2,404,512 7 I ‘ her 2, might .accomplishisuch ‘movement and/the effect of such low-pressure actingin chamber =24 ‘on, plunger-2| against’ the pressure of; controlling to-move'plunger 22‘ inthe direction of‘the relea valvei‘45 which‘iat this time will be held-stationary’ with plunger 2|. *This plunger 22 will thus; con tinue to move until itcontacts'the release valve 45 whereupon‘ further release of ?uid under- press sure, from the-‘power piston-chamber '2 '-will 1be ipreventedzand said piston will stop in a position‘, it will be vnoted, corresponding to that of plunger ‘2| 'andlin turn'to the?‘ reduced pressure. of. ?uid in'chamber |2.<' a -' " I‘ ; - ?uid in chamber l2 on diaphragm _|;3. might ‘not . cause any material change in the adjustment of plunger 2| and hence in the'accuracy of adjust ment of piston | in accordancewith'the pressure of‘ ?uid provided inchamber I2. i However,="ifr a much greater. force were ' required ‘to v‘move-the 10 deviceto the certainlposition above mentioned‘, ~ ‘Upon a further reduction in pressure in ch-am; the correspondingly'greater pressure :of ?uid 'ree . ber ,IZthe 'plunger'll will ‘assume a new position quired‘on piston-‘I :mightnot be obtained‘with the chosen controlling pressure inllchamber I2’, corresponding to such pressure,’ and'the opening and then closing of the_release valve 45 will cause the power piston l to move to’ a new-and corre sponding position. ' ' . ' ' ~ since the increased pressure in'ch‘amber' 24 might 15 be su?icient to move'plunger 2| 'againstfthe oppos ing pressure of ?uid in chamber |21and permit 1 ' - Upon'a'complete release of ?uid underpressure closing of the supply- valve ‘40 before obtaining - from chamber l2, the spring 10 will return the said greater pressure; To obtain'the'greater'prese diaphragms and, plunger 2| to the positions shown , sure the operator wouldthen have to increase in'fthe drawing and the action'of spring53 on 20 the pressure in chamber: | 2 to. compensate for the release valve stemgd? will then continue move ment'of vsaid diaphragmsandof plunger 2| to said greaterpressure and thus above the degree normally required toobtain the desired position theposition de?ned ,by- contact between the nut ing of the device. The structure shown in the ~ drawing and above described avoids such di?icul pressure from piston chamber 2 will then. occur 25 ties however and‘ ensures thatlthe piston: liwill and the piston, |will be returnedtoward its nor assume a position"corresponding?to the pressure ’ mal position actuating the follow-up member N62 of ?uid provided‘ in chamber | 2, regardless for the 35'and stop 12. I A furtherreleaseofj?uidunder ,to move plunger 22 in the direction of plunger ‘2| as " above described; pressure of ?uid-required‘in chamber. 2’ to move 7 However.’ with the plunger thepiston | to the chosen'positioni': ; ' ' w , . . 2| in the position de?ned by. contact‘ between nut 30 Having now described, our invention, Whatiéwe 35 and. stop 12, the end of theipiston'rod'? ,will claim as new and desire’ tofsecuresby Letters engage stop 8 with plunger 22;stillout of engage Patent, is: f v := ~ ‘ ' ment with the release valve 45, so'that a com pleterelease of v?uid under pressure from piston chamber 2 will occur. 7' ~ - e - 7 1. Af?uid pressure control device comprising ' spring means, movable controlmeans subjectlto 35 pressure of said spring'means and ‘to opposing It will now be seen that by decreasing -' the pressure of ?uidin a chamber, means providing forvarying the pressure of ?uid'in said chamber, pressureof ?uid in'chamber l2, the structure will operate to cause the piston | and devicebe ing operated to assume a position corresponding to such decrease,‘ or a plurality of different se lected positions successively upon a series of chos a plunger connected with and‘ movable by said control means and having a supply chamber sup-1 40 plied withu?uid under pressure, a su-pplyyalve carried by: said plunger and operable to supply V . en reductions in the pressure of ?uid in chamber l2. Moreover it will also be seen from the above " description that the operator by providing suit e?ect closure of said‘ valve, and means'subject able pressures of-?uidin chamber |2 may cause the power piston .|_ to move ?rst in one, direction and then in the opposite direction to obtain any chosen adjustment, or series of di?erent» adjust ments, or change in adjustment of the device be ing operated. - g - < . r ; . _It will be noted that whatever pressure of ?uid is effective in chamber 2 on the power piston‘ I is likewise eifective in chamber 24 in plunger'Z I. This pressure of ?uid on plunger 2| opposes-pres sure of ?uid in chamber l3 on diaphragm ~|2 ?uid under pressure from said supply chamber to a control cha‘inbenseatin'g means operable to to pressure of v?uid in said control ‘chamber. oper able upon movementfof said plunger by‘an in-' 50 crease/in- pressure of ?uid’ in the ~?rst= named chamber» to open? said supply valve and operable by pressure of ?uid provided’ in said ‘control chamber to render said seating means operable to effect closure of said supply valve.’ 2. A ?uid pressure control ‘devicecomprising spring means, movable-control means subject to pressure "of said spring means and to opposing pressure-of ?uid in'a, chamber, mea'nsproviding and thus tends to change the positionof plunger 2| as chosen by the pressure of‘ ?uid provided in said chamber by the operator. [This tendency. a plunger,‘ connected with and movable by said 7 is howeverrcounteracted at all times by-subject plied with ?uid under‘ pressure, a supply valve ' ing plunger 13 in chamber 16 to thesame pressure of ?uidas acting in chamber 24 on plunger 2| so that regardless of the pressure of ?uid provided I, to'ac'tuate the power piston I the position of plunger 2| will always correspond to the pressure of?uid provided in chamber |2,>and'in turn, the position oflthepower piston- I, will likewise correspond to suchpressure of ?uid. 7 This structure andffunction just described: is . V of particular. importance where‘a device being operated requires di?erent degrees of actuating force in different positions of the device, and hence in different positions of the power piston. For instance, if only a relatively small actuating force were required to move- the device to a certain position a relatively low pressure of ?uid in chain-g for varying the ‘pressureof ?uid’in said chamber,‘ control means and having a supply chamber sup-. carried by'said plunger and operable. to supply ?uidunder pressure from said supply chamber to a control vchamber, seating means operableito' effect closure of said valve; said plunger project ing from one side of said control means and being subject to pressure of_ ?uid ‘in said control cham-‘-' her, a second plunger projecting'from the oppo-" site side of and connected'with ‘and movable by ' said control means and; subject to‘ pressurei'o? ?uid in said control‘chamber counteracting‘presi sure of ?uid in said control chamber acting ‘on’ the ?rst named plunger, and'means subject :to' pressure of ?uid-inv said control chamber'operable" upon movement of said, plunger by an increase’ in pressure of ?uid in the ?rst-named chamber to open saidtsupplyuvalvdand operable by pres-I 2,404,512 .9; sure of ?uid: provided‘- inzsaid' control‘: chamber to render saidi seating 1 means operable-1 to effect _ 7 . closure vot'saidi supply valve; 10 said? one plunger, said-diaphragm means‘being subject to} opposing ‘pressures: off atmosphere and’ of ?uid-ina control chamber, a regulating spring. 3: 'Ax?uid pressure‘ control?» device“ comprising spring‘ means, >movabl'e‘ control? means’ subject to and: adjustable‘: in. accordance‘ with the, differen als’oua‘cting on1 said 'di'aphragm‘mea'ns in opposi tial? between. pressure of "?ui'di in a‘- - chamber and: thetoppositeldirection to a'positioni corresponding opposing-atmospheric pressurevv plus pressure of: tion .to, pressure of‘?’uid‘ in‘, said? controli chamber, said: diaphra'gn'iv means‘ being‘ operable! to move said? ?rst plunger? in either, one direction»- or" in to the=pressureoi ?uid in- said control‘ chamber, said spring means, means» providing for‘ varia tions in.; pressure of“ fluid? in said chamber, a 10 and-‘means connected to- said control ch'amben providing for.“ varying‘ the pressure ‘of-I- ?uid‘ plunger: movable‘ by said movable control means and: having a ?ui‘di pressure- supply‘ chamber, therein. ‘- 1 _ ' ‘ ' m‘ean's‘ arranged’ to supply‘?'uid? under‘ pressure - 5*. A: ?uidi pressure» control device comprising a trol‘ means upon an increase in pressure off ?uid ance with-the degree of such pressure, the other casing having! two spaced apart‘, parallel arranged» to1 said supply chamber, a supply valve control ling? a ?uid pressure supply communication be 15' bores-a1 power piston disposed in one oflsaid; bores and‘v subject, on- one face to pressure of tween said‘ supply chamber andia control cham ?uid‘: in a- power chamber, a- spring in said=v casing ber, seating means operable to actuate said valve acting on‘ said“ piston‘ in opposition to pressure to ' close said- communication, v andI means subject of‘ ?uid'in- said' chamber ‘and ‘cooperative with, to3 pressure oil ?uid in: said?- control‘ chamber oper- " ableu-pon‘ movement of said plunger by said con 20 said? pressure~to> position‘ said-piston in accord-‘r inthe ?rst named chamberl‘to' actuate saitlsupply valve- to: open said communication and operable byv pressure ofv ?'uid provided2 in: said- control chamber to render' said seating means operable 25 bore: being open. at opposite ends to atmosphere, two relatively movable plungers slidabl'y mounted in. said other bore and cooperating to= form'a second chamberv between their adjacent ends, conduit meansrconnectin‘g said power chamber‘ to actuate said supplyvalvevtoi close- said com andvv said second chamber, one'of saidplungers having a supply-chamber supplied'fwith ?uid - di'A- ?uid pressure control device" comprising under pressure; a supply valve disposedwin's'aid a casing having two spaced apart, parallel‘ ar ranged bores, a- po'wenpiston disposed in'one of 30 supply chamber andarrangedv to control ?ow of“ ?uid under. pressure from said; supply chamber said bores and/subject‘ on onefaceto ‘pressure of’ to-sai'd second chamber'and power chamber, a‘ ?uid in a ‘power chamber, a spring in said casing release valve in said second chamber cooperative acting on said piston in opposition to pressure with said second- ‘plungerv to'iicont'rol‘ a ‘release ' of ?uid in said chamber and cooperative with communication for: releasing ?uid underipressure‘ “ said pressure‘ to- position? said piston in accord from saidiisec'o'nd? chamber‘ and‘power vchamber; ance w-itl'1*~ the degree of such pressure, the other said one plunger being operable upon movement bore being open at opposite ends to atmosphere, relative to and in the direction of said second. two relatively movable plungers slidably mounted plunger to effect closure of said release valve in said other bore and cooperating to form a and opening of said supply valve and being oper second chamber between their adjacent ends, munication. - - Y‘ ‘ ‘ '“ , i‘ conduit means connecting said power chamber and said second chamber, one of said plungers having a supply chamber supplied with ?uid under pressure, a supply valve disposed in said supply chamber and arranged >.to control ?ow of ?uid under pressure from said supply chamber able upon movement in the opposite direction relative to said second plunger to effect open ing of said release valve, and said second plunger being operable upon movement relative to said one plunger in a direction away fromsaid one plunger to effect closure of said supply valve and in the opposite-direction to eifect closure of said to said second chamber ‘and power chamber, a release valve, lever means connecting said piston release valve in said second chamber cooperative to said second plunger ‘and having a fulcrum with said second plunger to control a release communication for releasing ?uid under pressure 50 connection with said casing and operable upon movement of said' power piston in response to from said second chamber and power chamber, an increase in pressure of ?uid‘in said power said one plunger being operable upon movement chamber to render said second plunger movable relative to, and‘in the direction of-said second inra direction away from said ?rst plunger and plunger to'e?ect closure of said release valve and in response to a reduction in pressure of ?uid in ' 55 opening of said supply valve and beingoperable said power chamber to move said second plunger ' upon movement in the opposite direction relative in the direction of said ?rst plunger, movable. to said second plunger to effect opening of said diaphragm means disposed in said casing in co release valve, and said second plunger being oper axial relation lwith and connected to the other able upon movement relative to said one plunger in a direction away from said one plunger to 60 end of said one plunger, said diaphragm means being subject to opposing pressures of‘ atmos effect closure of said supply valve and in the op phere and of ?uid in a control chamber, a reg¢ posite direction to effect closure of said release ulating spring also acting on said- diaphragm‘ valve, lever means connecting said piston to said means in opposition to pressure of ?uid in said. secondplunger and having a fulcrum connection control chamber, said diaphragm means being‘ 65 with said casing and operable upon movement operable to move said ?rst plunger in either one of said power piston in response to an increase in pressure of ?uid in said power chamber to render said second plunger movable in a direc-' tion away from said ?rst plunger and in response ,70 to a reduction in pressure of ?uid in said power chamber to move said second plunger’ in the direction of said‘ first plunger, movable dia-Y phragm means disposed in said casing in coaxial direction or ‘in the opposite direction to a posi tion corresponding to the pressure of ?uid in said control chamber, and means connected'to said control chamber providing for varying the pres_ sure of ?uid therein, said diaphragm means com prising two spaced apart‘?exible diaphragms co operating to form a chamber between them, conduit means connecting the last named cham- ' relation'with and connected to the other end of 75 her to said supply chamber, and. a ?uid pressure 111i 2,404,512 12 supply pipe connected to"the chamber between V from said’one plunger to I e?ect closure of said the two diaphragms for supplying. ?uidrunder supplyvalve and in the'opposite direction to pressure thereto and to said supply chamber. . ,i ' e?‘ect closure of said release valve, lever means 6._A_?uid pressure controldevice, comprising a casing having two spaced apart, parallel ar ranged bores, a power piston disposed intone of said bores and subjecton oneface to pressure of ?uid in a power chamber, a spring in said casing acting on said piston in opposition to pressure of ?uid in said chamber and cooperative with said pressure to, position said piston insac-l cordance with the degree of such pressure, the otherbore being open at opposite ends to atmos phere,_two relativelymovable plungersslidably . connecting said piston to said second plunger and having a fulcrum connection with said casing and operable upon movement of said powerjpiston in response to an increase in pressure of ?uid in said power chamber to render said second plunger movable in a direction away from said 0 ?rst plunger and in response to a reduction in pressure of fluid in said power chamber to move said second plungerv in the direction of said ?rst plunger, movable diaphragm means disposed in said casing in coaxialrelation with and‘con mounted in said other bore-and cooperatingto' - 7 nected to the other end of said one plunger, said form_ a second chamberbetween their, adjacent‘ ends,,_conduit means connecting said power' chamber and saidrsecond chamber,_ oneof said plungers'vhaving a supply ‘chamber supplied withv ?uid under pressure, a supply valve disposed-Yin: saidsupply chamber and arranged to control ?ow o1’ ?uid under pressure from said. supply cham ber to said secondchamber, and power cham berbagrelease valve in said second chamber co.» operative with said second plunger; to 7 control . a_releasecommunication for releasing ?uidunderl pressure ‘from said second chamber and power; chamber, said one», plunger beingoperable .;upon 1 diaphragm means being subject to opposing pres-, sures of atmosphere and of ?uid in a control chamber, a regulating spring also acting on said diaphragm means in opposition to pressure of ?uid in said control chamber, said diaphragm means being operable to move said ?rst plunger in either one direction or in the opposite direc tion to a position corresponding to the pressure of ?uid in said control chamber, another plunger slidably mounted in said casing in coaxia1,re1a-. tion and connected to said one plunger and sub-V ject to‘ pressure of ?uid in a chamber WhiCh'OD; poses pressure of ?uid in said second chamber movement relative to, and in the direction of; acting on said one plunger, conduitv means es saidv second plunger, to effect closure of said re: 30 tablishing a ?uid ?ow communication between lease valve and, opening of saidv supply valve; ' the two last named chambers, and“ means con and heingreperable upon; movement in the op.—' posite; direction relative to ,said ..:second _ plunger, ' tqe?eqt vopeniris. ofsaid release valve, and said‘ 1 seqond rlungenbeine operable upon . movement l 35 relative to said oneplungenin a direction away : nected to said control chamber providing 'for varying the pressure of ?uid therein. ‘ , ,QHARRY 0. MAY, ‘GLENN T. MccLUREQ .