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July 369 îlgáìä . a N. ASHTON ¿495,006 AUTOMATIC CUÍTOFF PUMP Filed Jan. 27, 19444 mKNN wm www 2 Sheets-Sheet 1 July 30, i946, B. N. ASHTON l 2,405,006 AUTOMATIC CUTOFF PUMP Filed Jan.. 2'7", 1944 2 SheetsFSheet 2 E @Y ,firm/mim Patented July 30, 1946 2,405,006 lUMTED STATES PATENT oFFicE 2,405,006 AUTOMATIC CUTOFF PUMP Benjamin N. Ashton, Kingston, N. Y., assignor to ^ Electrol Incorporated, Kingston, N. Y., a corpo - ' ration of Delaware - Application January 27, 1944, Serial No. 519,844 6 Claims. . y 1 (Cl. 103-23) 2 _ This 'invention' relates to` improvements in pumps and relates more particularly to continu ously driven pumps suitable for supplying liquid under pressure to hydraulic systems, such as, for example, the hydraulic vsystems used in aircraft for actuating retractable landing gear, folding wings, Wing flaps and the like. connected relationship until the pressure falls to a predetermined lower value. More particularly, pumps of the type embody ing the present invention may include a plurality of cooperating cylinders and pistons provided with suitable intake and discharge ports through which liquid may be drawn and discharged by the action of the pistons. The pistons may be The .pump óf vsuch a hydraulic system usually is driven _by the aircraft engine and it delivers reciprocated by means of a suitable drive mech liquidunder pressure at all times during the op 10 anism such as a wobble plate that is actuated by eration oí. the engine. Inasmuch as the various means of a cam connected to and driven by the hydraulically operated elements of the aircraft are actuated intermittently, the continuously engine so that upon rotation of the cam, the pistons are successively advanced and retracted supplied liquid under pressure must be diverted in their respective cylinders. and recirculated in order to avoid excessive pres sure in_and damage to the hydraulic system. ' The liquid usually is V_diverted andlrecirculated by means otadevice known as an unloading valve, ¿whichfoperates -to bypass and return the liquid to a reservoir or tothe inlet of the pump when a predetermined pressure has been reached in the system. An object of the present invention is to pro vide a pump that is responsive tov pressure in a hydraulic system and is capable of maintaining in the system a hydraulic pressure within a pre determined relatively narrow range. n Another object of the invention is to provide a The wobble plate may be supported upon a piston member that is displaced by liquid pres sure on one side thereof to disengage the wobble .plate from the cam. -Liquid under pressure may >be supplied to displace the piston by means of a 20 valve mechanism that Yis shifted to an open posi tion by a predetermined iiuid pressure in the hydraulic system and maintained in such open position until the pressure in the system drops a predetermined amount. 25 When the pressure in the system drops to a predetermined value, the valve mechanism is re set to discharge the liquid from behind the wobble plate piston to permit the wobble plate to engage `with the actuating cam and actuate the pump continuously driven pump that automatically ceases pumping when a predetermined liquid 30 pistons. pressure is attainedin a hydraulic system, and Pumps of the type described generally above permit the unloading valve and associated con resumes pumping upon a predetermined decrease of the pressure in the system. duits of prior systems to be eliminated inasmuch A- further object of the invention is to .provide as the pump functions both as a pump and a a positive type of pump having continuously op 35. pressure control mechanism. erated driving mechanism that is rendered in For a better understanding of the present in eiïective -to actuate the pumping elements when vention, reference may be had to the accom the pressure in >the system attains a predeter panying drawings in which mined maximum value and in which the pumping Figure 1 is a view in longitudinal section of a elements are rendered eiiective when the pres 40 typical form of a pump embodying the present sure in the system falls below a predetermined value. ‘nventiom Figure 2 is an end view of the pump; and Figure 3 is an enlarged showing of a portion parent from the following description of typical of the pressure-responsive valve of the pump. forms of pumps embodying the present invention. The form of pump chosen to illustrate the in Pumps of the type embodying the present in vention includes a generally cylindrical housing vention include pumping elements that are ac I0 having a circumferential iiange 10a at one end tuated by a drive mechanism that is coupled to thereof which abuts against a iiange Ila on the and driven by a motor or an engine, for example, end of a generally cylindrical pump body portion an aircraft engine. The pump is provided with 50 ll. The pump body portion il, as illustrated, is a pressure-responsive mechanism that is actu ` provided with a plurality oi’ cylindrical bores I lb ated, upon attainment of a desired liquid pres forming cylinders disposed around its periphery sure in an associated hydraulic system, to dis for receiving the cylindrical pistons l2. The pump body portion ll is also provided with a connect the drive mechanism completely from Other objects of the invention will become ap the _pumping elements and maintain such a dis cylindrical recess llc forming another centrally ¿4051006 3 "iff: if... with each of the pumping cylinders l Ib by means cylindrical portion 28a of the member 28 is re ceived in a cylindrical cavity 28h coaxial with the of the inlet ports I ld. At the left hand end of each of the bores iIb is a bushing I3, forming a check valve seat, which is threaded into the member I I and sealed there lying the race 2‘Ic. The clamping member 28 may be retained in position by means of a bolt 23 disposed cylinder therein which communicates recess 26a and similarly inclined at an angle to the axis of the shaft 22, with its flange 28h over threaded intothe. .member 2S. to by a suitable sealing ring |3a.» _--The cooperat mutation on a ball member 3| mounted on le ~and a"shaft 32. The shaft 32 is slidably and rotat ably mounted in the end of the pump body || and extends axially of the cylindrical cavity ||c into fthfe Cylinder L59. @The ball 3| is mounted on a is normally urged toward its valveseat »i3by means of a coil spring I5 interposed`bet'we`enïthef~ back of the plug I4 and the end closure cap IS of the pump. When the plug |_4 is seated, it en gages the sealing ring Iâî) 4and the face of the ` seat I3 inwardly of the ring I3 so that liquid pres sure on the ring Iâhand the plug I4 provides a reduced portionß‘gìd of the shaft 32 and is re tained thereon by means of a nut 33. The wobble plate 30 includes a pair of telescopically assem . bled-disc-like members 30a and 3ûb having a partially spherical aperture 35e therein for re ceiving the ball 3|. The members _373e _and 30h strong and complete séál _betweenthe plug I4 _ Y ' _, ' _. .. a wobble plate 3D thatismcunted forP rotation may consist of a cup-shaped element havirne‘ a flat cr disc-like valve face |4a that cooperates with a »sealing ring |3b mounted in a groove |36 in the valve seat I3. Each of the valve »pl-ugs I4 and theseatilì. ,l ._ 'ïîhe outer race'f2'l‘a o_f ïthebeariugzjpngages ing element`.o'r'.valvè}fplug I4 of the check ¿valve have an inter?tting projection 3_Ild_a_nd_reces_s _38e _ `.Asshown in Figure 24 the capl Ilì is‘generally dis’o'ëlìlçe in plan and is provided ,with an annular axially'd'irectedflange |80?l that abuts against the ña?igeflIa ofthe pump body. vThe cap I6, the pump'body II' and the casing Il! may be secured together by means_ef va plurality- of bolts |1 pass andare connected by means '_of 'a‘ series of 'bolts 35 _which extend through overlapping portions ingA Ahrough the ,ñanges lila. |€a_ and threaded threaded into an internally threaded portion' of intolth'e -flange |641.- _ _ ' _ of themembers 30a and 30D. - ' ' The wobble plate _30 is provided with a plurality of radially extending openings 301‘ _for receiving the studs 36. Eachfof thestuds 36 is Provided with a reduced threaded ’portion 36a which is l the bores 30f. j Escape of liquid from between ‘the cap i6 vand `-: ' ' '_ ff - , " ` The studs 36 -have Vgenerally spherical `heads> the. flange IIa’ maybe prevented by means- of 36h that are received in transverse openings I2a a suitable rubbery sealing ring or gasket I8 re ceivedr in a groove IIe in Íthe pump body and en in _the reduced end 'portions 1.21) ofthe pistons I2 so that nutation ofthe wobble -plate '30 will cause _the pistons“__|2_-to reciprocatein the cylin gagíng the .flange IBG.' The pump cap I6 iS pro vided with ananfnular flange _I Bb concentric with Tìhëi flange 'lie re’ò'eîifedßslessp'pîcally inthe.. ders _`||b. ->'l'husjiupon'rotation‘ of the shaft 22,` theïdr'" _'ng ¿ein 21 will-‘cause ,riut'auon'of the' wob bie' pratëiaviändï ui'ëfîbis'tohswiu be‘ actuated to sealedftîïêîetolby Cylindrical. recessmeans'of ¿IIC .G_Lf îthe ‘al rmripbedy ali‘ngrin'g‘or and gasket the' _liquid 'to' tlíeîhydraulic 'system'.f ISmounted‘in an annular groove _läd 'in the nan‘ge pressures vby the system by the pump', the cap |6 of the pump is provided with- a valve -mecha. nism which -controls the position of the `wobble plate 30 and renders theyistons I2 'effective'or ih_ë ‘flange- Iêd and an’i'uner concentric flange |5c forming, 'a _cylin'd „ riapurpose‘to' be described. draw liquid into the‘cylinders Iflb -and discharge-Y lin-order- tó 'avoidwthè' development 'of excessive |612; vThe annular space 2_9 between the flange ißc and the ilange` Iëb‘ communicates with a dis charge coupling Iâe inthe cap I6. The coupling I_lìc is. adapted to be connected to a hydraulic .Sys 45 ineffective to pump, depending upon the pres tem so that -the liquid forced from the cylinders |_ lb> through the check valves I3, |4 into the cavity sure in the system. tem for use'in actuating various elements ccn nected therewith. - ' ' _' - ' ’_I‘he valve, together with the inlet port |6f and 29___will be „delivered directly to the hydraulic sys so lï'h'e cylinder I__Ic >andthe space'2! within the flange Iëb are'~conne~cted to an inlet coupling |6í the discharge port |66 is disposed in a boss or a thickened portion I_Bg on the cap I6 as shown in Flgures'l and 3 of the drawings. The boss |69 in. the c'ap‘lûso that liquid _from a reservoir or from the hydraulic system-:can ñow into the cyl is provided with an axially extending bore -Iíïh which terminates adjacent to thedischarge cou pling IBe and is connected thereto by means of a inder itc and tothe intake ports lld. ` :The pistons i2 are actuated'by means of a shaft annular valve seat 40 having a. tapered opening small passage _|612 Within the bore _ISh'fis an 40a communicating with a-cylind'rical passage 4Gb defining with the'upper face _of the member 40 a 22'thatis driven by a motor or engine. The shaft is journaled in suitable anti-friction ~_bearings 23 ¿ne 24 that are mounted in a portion lob or _the sharp edged `'valve sea-t v_llllcjf'o?a ball valve 4|. casing I3 of reduced diameter. In order to pre andis maintained in- spaced relationship tothe A sleeve member Y42 is ldisposed in the bore |671' vent leakage around the shaft, an oil seal 25 of member 4D by means of an annular spacer mein conventional type may be interposed between ‘the shaft and vthe portion lilb- Of the casing. The -inner' end of the shaft 22 is provided with accunter-balanced driving cam. For example, the shaft 22 may be provided with a counter balancing member 26 having an eccentric and in clined arcuate recess 26a therein for receiving a ber 43 of generally VL-shaped cross-section. ' 'v The member 42 is provided »with an enlarged internal bore 42a and a smaller passage 42h that forms with the lower face of the member 4_2- a sharp edged valve seat 42o for the ball "4|.-` -The diameter of the passage 42h is somewhat greater than the diameter of the passage '401). roller-bearing’driving member 21.' The driving member 2ï may include an outer' race 21a sup ported by a plurality lof tapered roller bearings 2lb and an inner race member fìlc. i The inner race Zic is clamped in the recess 26a onthe coun 70 ' ` t The ball 4| is normally-urged against theï-valve seat 40o by means "of _a plunger-"44which ex tends axially of the bore -I Gg? and is provided with a reduced end- portion- 44a that ~projects through passage 4_2?) andA _engages -_th`e "'ball." The ter-'balancedmember 2S by means o_f'a flanged, _ the~ cup-shaped, clamping VAmember 28; The base or 75 plunger 44 -is also-provided with la-'i‘lamgeMb that 2,405,006 .5 is engaged by a coil spring 45 extending between the llange 44h and a member 46 threaded into the outer end of the bore lIîg for adjusting the prese sure exerted by the spring 45 on the ball 4I. The members 40„43 and 42 are retained in ñxed relationship by means of a tubular sleeve 41 threaded into the bore IIìh and retained in iixed position by means of a lock sleeve 48 also thread ed into the bore IBh. 6 square inch. When the pressure in the system attains the desired value, the back pressure in the system, acting through the passage |61' will displace the ball 4I from the valve seat 40e against the action of the spring 45. The spring 45 is adjusted or selected so that it will re tain the ball 4I on the valve seat 40o until the desired pressure is attained in the system. When this pressure is attained, the spring 45 is com The spring adjusting member 45 is provided 10 pressed and the ball 4I is displaced upwardly as viewed in Figure 1, urging the ball against with an internal flange 46a that closely receives the valve seat 42o. Inasmuch as this valve seat the plunger 44. A resilient sealing ring 49 is in is of a greater diameter than the valve seat 40o, terposed between the flange 46a and a ring 50 the effect of the pressure on the ball 4I is con against which the spring 45 bears to prevent leak siderably increased. Thus the diameter of the age around the plunger 44. The adjusting mem seat 42e may be such that the pressure in the ber 46 may be locked in `adjusted position by system»must drop to 900 lbs. per square inch means of a lock nut 4Gb threaded on its exterior before the spring 45 can return the ball 4I> to and engaging a compressible gasket 45e received the seat 40e. in a recess |67’ at the end of the boss I6g. The spacer member 43 is provided with one or ,A more radially extending ports or passageways 43a that communicate with a groove 42d in the outer periphery of the member 42 and a passage 5| in the cap member I6 communicating with the space within the tubular member I6c in the in terior of the cap I6. The interior of the cylinder IIc and the space between the flanges I6b and I6c are connected with the interior of the sleeves 41 and 42 by means of a passage 52 and a passage 41a through the sleeve 41. With the ball in its displaced position, liquid flows through the passage 43a, the groove 42d and the passage 5I into the Space between the end of the plunger 32h and the annular flange IEc. The liquid also flows through the passage 32o and 32d behind the piston 53, thereby urging the piston to the left against the action of the spring 54 and moving the wobble plate 30 out of engagement with the drive member 21. In the form of the invention illustrated, the wobble plate 30 will engage the end of the pump body portion II and will be rocked into a position substantially perpendicular to the axis of the shaft 32. This movement of the wobble plate advances all of the pistons I2 to the left where they are retained so long as the ballv 4I is dis placed from the seat 40C. When the pressure at the discharge port or The valve construction and passages described above are utilized to actuate a piston 53 that is fixed to and carried by the shaft 32 and movable axially of the cylinder IIc. The area of a face of the piston 53 is greater than the combined areas of the faces of the pistons I2. The piston coupling |66 decreases sufñciently, the spring 45 53 is sealed to the cylinder I Ic by means of a and plunger 44 displace the ball from the valve rubber sealing ring 53a supported in a peripheral seat 42o and return it tc engagement with the groove 531) in the piston. The piston 53 and the seat 400. In this position, the liquid behind the shaft 32 are normally urged toward the right by piston 53 flows through the passages 32d, 32o, means of the spring 54 that engages the piston the passage 5I, the passage 43a, the port 42h, 53 and the cap member I6 and encircles the shaft through the ports 41a and 52 and into the cylin 32. The shaft 32 extends beyond the piston 53 and is reduced in size to form a piston 32h that 45 der IIc. This releases the pressure behind the piston 53 and permits the spring 54 to move the is slidably received within the tubular rmember I6c. 'I’he piston 3217 is maintained in liquid tight relation to the member I6c by means of a rubber sealing ring 54 and is provided with an axial bore 32o that intersects an inclined passage 32d opening to the exterior of the shaft 32 at the right hand side of the piston 53 so that liquid flowing through the bores 32e and 32d will be discharged into the space between the right hand end of the cylinder I Ic and the piston 53. A suit able sealing ring or gasket 55 may be interposed between the cylinder IIc and the casing I0 and encircling the shaft 32 to prevent leakage. In operation, with the shaft 22 driven con tinuously, the wobble plate 30 is nutated to re 60 ciprocate the pistons I2 in their respective cylin piston to the right, thereby reengaging the wob ble lplate 39 with the driving mechanism 21 and causing a resumption of the pumping opera tion. The above described construction, therefore, provides a pump which automatically cuts off at a predetermined pressure and resumes pumping at a lower predetermined pressure, thereby do ing away with the necessity of providing a sep arate unloading valve for a hydraulic system, while assuring that the pressure in the hydraulic system will remain within a. desired operating range. While the invention has been described with reference to a piston type of pump, it will be understood that it may be utilized in conjunction ders IIb.v Liquid is supplied through the cou with other types of positive acting pumps. plingf I6f to the cylinder IIc and is drawn into Therefore, the form of the invention as de the cylinders I Ib through the ports IId by means scribed above should be considered as illustrative of the pistons I2. As the pistons advance past and not as limiting the scope of the following the inlet ports IId, the liquid is forced out through the check valves I3 and I4 into the claims. space 20 and` thence to the discharge coupling I claim: ISe. As the pistons retract, the check valves 1. An automatic cut-off pump comprising at I3, I4 close and a reduced pressure is created 70 least one pump cylinder having an inlet and an in the cylinders, thereby drawing the liquid into outlet, a piston reciprocable in said cylinder to the cylinders IId for subsequent discharge. As draw liquid into said cylinder through said inlet the pump continues to operate, the pressure of and discharge liquid through said outlet, rotary the liquid in the system is increased to a pre driving means, a wobble plate actuated by said determined value, for example, 1090 lbs. per 75 rotary driving means for reciprocating said pis 2,405,006 7 8 ton, and means responsive `to va predetermined liquid ¿pressure :at .the outlet of said cylinder for shifting said »wobble plate «out of »engagement with said rotar-y driving means to render that `latter able member, said means retaining said wobble .plate in shifted position until the `pressure in saidsystem .drops to ya predetermined `lower value. 5. An automatic cut-.oli pump .comprising at ineffective to reciprocate »said piston, said `pres least one .cylinder .having an inlet .and .an outlet, sure .responsive'means being responsive .to a lower pressure than said predetermined pressure to a ,piston ,reciprooable in said .cylinder for `admit ting liquid through ,said inlet into said .cylinder and discharging liquid under 4pressure through shiftsaid wobble plate into engagement with said rotary driving means to render the latter «effec tive 4to reciprocate said piston. said outlet, a rotatable member having .a face .rin 10 clined to the axis .of .said cylinder, a wobble plate liquid from `said outlet under pressure, Y.a ymtary cam member ladjacent ,one end of said piston, a connected to .said piston, .means supporting .and urgingsa'id plate against said inclined face to re ciprocate said piston upon rotation of said mein ber, a piston on said supporting and urging means, a .cylinder for said last-mentioned piston, a valve >having a ¿first port connected with said power transmitting element engaging said _piston outlet .and the last-,mentioned cylinder, a sec .2. An automatic .out-off pump comprising a `cylinder having an 'in-let 'and an outlet, a piston reciprocable in said cylinder to dra-w liquid linto said cylinder ’through ysaid inlet and .discharge and said cam member for reciprocating said pis ton >in response to rotation of said cam, and means responsive to a predetermined liquid pressure at said outlet for moving ysaid power transmitting element .out of .engagement Ywith said cani to ter minate reciprocation .of said piston. '3. automatic cut-ofi ,pump Icomprising a 'pump body having >a plurality of substantially @parallel cylinders radially spaced about the axis of said body, pistons reciproca-ble -in said cylinders ¿for `drawing liquid into -said cylinders and dis charging .'liquid yto a ihydraulic system, a driving -memberhaving a vface inclined tothe axes of lsaid ‘ ond port connected with said last-.mentioned cyl inder and said inlet, a Vvalve member for sealing either of -said ports and means normally urging said valve member into said first port, whereby displacement of said valve member from said ñrst port by liquid pressure >atsaid outlet admits .liquid .to .said last-mentioned cylinder to `displace said wobble plate from engagement with said inclined face, and displacement of said valve memberirom said second -port discharges liquid ’from said vlast mentioned cylinder to Areengage said wobble plate with said inclined face. v6. An automatic .cut-olf pump comprising .a body and said cylinders, and adjacent to Ithe pump body having a substantially centrally .dis end of each of said pistons, a wobble plate oper ated by said .member interposed between said end of each piston and said driving member, means .urging said end of each piston'toward said driv~ .posed cylinder and a plurality .of substantially ing member, means for rotating said driving of said smaller cylinders, a larger piston in said parallel smaller cylinders disposed radially out wardly .of said centrally disposed cylinder, each having an inlet and an outlet, a piston in each centrally disposed cylinder, a Vshaft projecting `member .and .said body relatively to cause nuta~ from said larger piston, 4a wobble-plate mounted tion .of ¿said wobble ¿plate to reciprocate said pis for nutation on said shaft and connected to .each tons'in said cylinders, .and mea-ns responsive to a tpredetermined pressure tin said hydraulic system (if) of the _pistons in said smaller cylinders, a rotat able -driving member having an inclined face ad «for shifting said wobble plate to move said ends jacent >to said wobble plate for nutating the latter vof said .pistons :into Aa plane substantially per -to reciprocate said .pistons in said smaller cylinpendicular to theaxis‘of said -body to .render rela ders, means urging .said >wobble-plate and large 4tive rotation 'of said body and said idriving mem 1 Vpiston toward said .driving member, a two-posi :ber ineffective ïto reciprocate said pistons. tion valve having -a ñrst port vconnecting said ¿4.,An :automatic vcut«o?f ¿pump comprising at centrallydisposed cylinder with the outletsvof said Vleast one 'cylinder having ¿an inlet .and an outlet, smallerl .cylinders to deliver liquid under pressure a :piston reciprdcable :in said .cylinder 'for ,ad-mit yto »displace said larger piston in Opposition to «ting .liquid 4through said inlet 'into -said cylinder and discharging liquid under pressure through »_, -sai-d Avurging means, a second larger _port connect Íing the centrally `disposed cylinder with said in .said .'.outlet, .a rotatable Vmember having a face vin lets -to discharge liquid from said .centrally dis clined-to theaXis-oi said cylinder, a'wobb-le plate posed ;cylinder to said inlets, a valve member .for connected `to said piston, ymeans supporting and sealing said Iports alternately, and means nor«urging said plate .against said inclined >face to - ~, mally urging said valve member intosealing rela reciprocate .said .piston .upon rotation .of said b. tion with said yiirst port. member, .and means responsive to a predeter BENJAMIN N. ASHTON. mined _pressure at said outlet for yshifting vsaid -wobble plateout of engagement with _said rotat- .