US2351817A

US2351817A - Fuel pump

Info

Publication number: US2351817A
Authority: US
Inventors: James P Johnson
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-10-10
Filing date: 1940-10-10
Publication date: 1944-06-20
Anticipated expiration: 1961-06-20

Description

Jue 20, 1944.

J. P. JOHNSON FUEL PUMP Filed oct. 10, 1940 .2 Sheets-Sheet 1 95 gg 9509 2a M lll f///. l/////'M 77' 40/ gli l.,

v 0 7,5 f4 f/ f6 INVEN'IOR.

JAMES RJH/v Ffa. 2

June 20, 1944. J, P. JOHNSON 2,351,817

- FUEL PUMP Fi1ed Dt. ICN), 1940 2 Sheets-Sheet 2 BY f ATTO

,Patented `June 420, 1944 fu-Nrlflzp s'rAfrEs PAT ENT 'susanna' James P. Johnson, Shaker Heights, Ohio Application October 1I, 1940, Serial No. 380,029A

. 8 Claims. This invention relates to fuel pumps of the rotatable multi-vane ticularly to improvements in a power driven fuel pump, embodying a relief valve for return of excess fuel and a by-pass valve, especially adaptable for use on aircraft although in no manner so restricted.

Itis a primary object of the present invention to provide a pump bore having diametrically opposite working radius and connecting faces conforming to a common radius nearly approximating the radius of the working faces thereby having the least amount of cam action in thevbore, is the nearest a perfectly round bore; and at the same time is geometricallv correct during the working cycle thus affording greater displacement with lesser pulsating characteristics.

Another object of the present invention is to provide shoes or rockers at'the opposite ends of the vanes. slidably engageable with the wall of the bore, the engaging surfaces of the shoes conforming to the radius oi the working faces of the bore thus affording better working conditions. reducing wear, and providing an eil'ective seal.

Another object of the present inventionls to Vprovide a novel double'rotatable seal to prevent escape of fuel from the Dump chamber and leakage of oil past the drive shaf Another object of the present invention :is to provide an improved fuel relief valve ofthe diaphragm type unaffected by `pressure at the inlet side of the pump present under certain conditions whereby the valve will enectlvely function to return excess fuel in the manner intended.

Another object ofthe present invention is to provide an improved by-Dass valve affording means through which fuel may be suppliedfrom an external source in the event'the pump becomes inoperative for `any reason whatsoever.

Another object of the present invention is toprovide a fuel pump which is simple in construction, elcient in operation and inexpensive to manufacture.

With the objects above indicated, and other objects hereinafter explained in view, my invention consists in the construction and combination of elements hereinafter described and claimed.

Referringto the drawings.- Figure 1 is a longitudinal vertical sectional view of a fuel pump 'embodying the present invention.

Figure 2 is a transverse vertical sectional view` taken along line 2.-! in Figure 1 andv showing or blade type and more parfaces conforming Yto the same (CLN3-42) further details of the the invention.

Figure 3 is a transverse along the lin'e 8 3 in oFFlcE pump structure embodying sectional, view taken Figure 2 and showing details of the by-pass valve means.

Figure 4 is a fragmentary sectional view taken alon line 4-4 in Figure 3 and showing further details of the by-pass valve.

Figure 5 is anend elevational view looking at Figure 6 is a fragmentary Y modified form of relief valve embodying the present invention. l5

Figure 8 is an end view sleeve showing the shape Figure 7 is a perspective vanes or blades of the rotor.

of the pump chamber view of Vone of the of the bore and the relative positions of the 'radius centers on an'en- 20 larsed scale.

In the drawings I have illustrated a power driven fuel pump embodying the present invention but the latter is in no manner to be so restricted, other adaptations being obvious to those tending inwardly from one preferably made of disposed bore Il ex end thereof and ter- 80 minatlng adjacent an integral end wall I2. A

pair of bearing members il, of bronze or other suitable material, iB disDGSed Within the-bore Il in longitudinal spaced of said bearing members or other similar material. bore' Il, extending between and is Provided with relation relatively, one being adapted foi` abut- 'ss ment with the inner face lof theend wall i2 to definitely Position the same. A sleeve Il, of steel is disposed within the the bearing members an eccentrieally disposed o bore il which extends longitudinally throughout its length. Bores provided in are of various forms, lemlcon curve, but in 45 ation of the pumps is a decided disadvantage for pumps at the present time the most common being the practically all of these types of bores the machining is diilicult and the operaccompanied by pulsations emcient pump opere tion. One of the important features of the present pumprtherefore. is to in the 'enlarged view reference should be had.

curvatures shown have been of this type and successfully operated, they are Il given for the purpose ofprovide an improved bore the details of which are more clearly shown of Figure 8 and to which While the relative embodied in mre l'edlly undefthe drive end and showing the plug securingv sectional view of a therefore in no wa'y limited. It is very desirable 'to provide a pump chamber bore which nearly as possible approaches a perfect circle, readily lends itself to manufacturing facilities, is understandable by the average mechanic and designer,` and is geometrically correct during the working cycle of the rotor blades. All of these features have beenattained in the present bore by the use of two radii, one eiecting the surfaces constituting A the working faces and the other effecting the surfaces constituting the` connecting faces, the centers being located on a transverse plane passing through the axis of the rotor as shown in Figure -8. The radius of the working faces is 1.600" and their respectivevcenters are spaced apart approximately .1394" both on the transverse plane. This curvature is at diametrically opposite sides of the bore and extends for approximately 67 degrees on both sides of the transverse plane where it intersects the bore.

The connecting faces also have identical radii but slightly shorter than those of the working faces and in the present instance 1.569" has been adopted. In other words, the nearest radius for continuously connecting the working faces is desirable and therefore produces a bore which is nearly a perfect circle aifording the best operating conditions. The radius for forming the connecting faces is struck from a common center positioned on the same transverse plane and mid--v way between the centers of the radii forming the working faces. The connecting faces extend over a portion of 46 degrees on diametrically opposite sides and as these do not enter into the work cycle of the rotor their curvature is not so important other than for the purpose already stated. e

The shape of this bore is well adapted for use with one or more through blades 'and in the present instance, referring again to Figures 1 and 2, a rotor I6, of steel or'other suitable material, is rotatably disposed eccentrically within the bore so as to have close running-engagement with the upper inner portion of the bore, its center of rotation being coaxial with the axisiof the outer 4 or other suitable material, is each provided with a recess 20 at one end to afford relative movement of one blade within the other and grooves 2I extending longitudinally on diametrically opposite sides of the blade as more clearly shownin Figure 7. A pair of these blades is mounted in the slots I8 soas to aord relatively sliding movement of the blades radially within the slots to adapt the outer ends of the blades for running engagement with-the bore at .diametrlcally opposite lpoints. A shoe 22, of steel or other suitable standing the objective of the invention and are bore'and shoes are always in sliding contact throughout the work cycle. The shoes further function as a packing or sealing means between the ends of the blades and the bore in which they rotate. It should be pointed out that by this construction a geometrically correct working cycle is provided during vthe working period, inasmuch as a uniform space or clearance is maintained between thev solid blades and thebore through the working cycle of the pump which is the distance between adjacent inlet and outlet port edges.l A pair of ports 23 and 24 is provided on diametrically opposite sides of the sleeve I4 of identical shape and extends transversely through the wall thereof Jto afford communication with the inside of the bore I5. To securely maintain the pump parts in assembled relation within the housing,a securing ring 25, of bronze or other suitable material, fits within the outer end of the bore I I and abuts the outer end of the bearing I3. A rubber ring 2B is peripherally disposed in a groove formed between the securing ring and bearing member to provide a fluid seal anda pluralityof screws 21 extend through openings in the ring 25 and are threadably secured in the adjacent bearing member so as to exert an outward pressure upon the rubber ring.A

The outer end of the-bore II in the housing is interiorly screwthreaded to receive an externally 'threaded plug 23 of aluminum or other suitable employed which extends through a transverse opening in the upper marginal portion of the bearing member and has its opposite ends disposed in aligned openings 30 and 3l provided inthe end wall I 2 and the adjacent end of the sleeve respectively. The housing III is further provided jwith a tapped inlet opening 32 and a tapped outlet-opening 33 disposed on diametrically opposite sides of the pump chamber and each communicates respectively at its inner end with the adjacent port 23 and 24 provided in the sleeve. It

material. is disposed in each of therecesses 2| at A the opposite ends of the blades and each is suitably mounted for relative rocking movement therein, the outer face of each shoe being formed over its entire face on the same curvature as that of the working faces of the vbore so that during rotation of the rotor the contacting faces of the 75 will be obvious that the construction so far provides for operation of the Dump in either direction of rotation and the pump is so adapted in a manner which will be later described.

'I'he pump is provided with a relief valve for by-passing fuel in excess of that capable of being handled by the carburetor. In the present construction, the by-pass valveis mounted in a bell-shaped housing 34 of aluminum or other light weight material removably mounted upon the upper rear portion of the housing I0. A gasket 35 is disposed between the contacting faces of the respective housings to afford a lfluid tight seal and a plurality of bolts 3B securely maintains the bell-shaped housing in proper po-` sition. -The housing 3l is provided with a transverse partition 31 having a centrallyvdlsposed opening 38 formed with a valve seat 3S at its up'- per inner edge. The housins PIODer l0 is provided with an opening I0 affording cornmunica-4 A Ation between the outlet side of the pump and theunder side of the partition 31, while the partition a1 is` provided with an opening u which com'- municates at the upper end with the upper side'- of the partition and at itsY lower endv with -a'n opening. 42 provided in the upper adjacent porposed tubular of the valve member ployed for controlling the iiow of excess iuel by the valve seat 39 but the'one illustrated embodies features which are particularly importantin aircraft. The valve member is a composite structure comprising an annular rubber valve head 43 having a beveled lower edge engageable with the v valve seat 39. The rubber valve head is mounted on a laterally extending flange 44 formed at the lower end of an inverted cup-shaped metal member 45 while a disc-like metal member 46 ilts over the upper face of the rubber valve member and has a depending marginal edge portion extending over the outer adjacent peripheral edge of the rubber vvalve head to secure it in place. The disc-like member 46 has an upwardly disportion 41 the outer end of which terminates in a laterally extending marginal ilange 49. A closed end tubular metal member` 49 fits within the tubular portion 41 and-has its lower end in abutment with the adjacent face of the disc while its outer end terminates in a iaterally extending marginal flange 50 disposed in spaced relation above the lateral ange 48, the flange 5l) being substantially coextensive with the valve seat 39 and having its extreme outer end turned downwardly. To secure the composite/ valve member in assembled relation for unitary movement a. 'pin 5| has its upper end extending beyond the iiange 50 and a disc ladjacent its lower portion engages the -closed end of the tubular member 49. The lower end of the pin projects through axially aligned openings in the bottom of the tubular member, the disc, and the cup-shaped lower member, and has its lower-end upset at 53 to provide av rigid connection for unitary 'movement with the valve head. To afford movement of the valve and at the same time to effectively seal the chamber above the valve seat, an inner annular metal disc 54 is removably mounted upon the adjacent portion of the bellshaped housing and has its inner marginal edge extending inwardly a suitable distance but spaced from the adjacent iiange 48. An outer annular disc 55 is disposed in cooperative relation above the inner disc and has its innermarginal edge bent downwardly at 56 in closely spaced relation with respect to the adjacent turned down end ofthe flange 50. A rubber annular disc 51 has itsV outer marginal portion secured between the adjacent faces of the lower. disc 54 and the upper disc 55 vand its inner marginal portion secured between the'lower iiange 48 and upper ange 50 before assembly, the intermediate connecting portion being looped downwardly at 58 thus an'ording a-exible joint. Due to the fact that vacuum is usually present at the inlet side of the pump,the looped portion 58 of the flexible diaphragm is positioned on the under side and the loop is relatively small due to the fact that the .v alve member has very little movement limited in a manner to be later described. There are times, however. -when pressure does exist at the inlet side of the pump, for instance, when the wobble pump is resorted to for by-passing fuel around the pump when the pump is inoperative for any reason. Also .pressure may exist, under flying conditions, where tilting or diving the. plane might present a head of gas at the inlet side. When this takes place the metal ilanges supporting the rubber diaphragm being disposed fairly close to each other willprevent the rubber loop from passing therebetween and be obvious inasmuch vilanges on one of ralitv of bolts 60 thus becoming inverted on the other side. y The inversion of the loop is further prevented by the downwardlyk extending marginal portions on the the stationary discs and on the valve member and even though, after long service, therubber becomes soft and ilabby the loop will remain in its proper position. l It is to be furtherpointed out that when adjusting for pressure-area the area of the dialphragm must be approximately the same as that to make it nearly balanced. i

of the valve in order The importance of a nearly balanced valve will as it aiords' the use of a :much lighter and lesser tensioned spring for preloading l the valve member thus reducing the weight of the pump and its overall size, and further will be unaffected by the pressure of the by-passediuel.

Any suitable lmeans may be -employed yfor pre loading the valve member but a simple and effective structure is shown in the drawings. The bell-shaped housing 34 is made with a removable upper cap portion 59 its lower face being engageable with the uppervannular disc 58 for securely maintaining the adjacent discs and rubber diaphragm in assembled relation and a pluportion of the bell-shaped .housing as a unitary structure. The capvhas an integral axially disposed extension 6| projecting on diametrically opposite sides of its outer end, the inner end being oi reduced diameter'E and piloted in the upper adjacent end of the tubular member 49 on the valve member. The inner end of the extension 6| has an inwardly extending axially disposed bore 62 to slidably receive the outer end of the pin 5I, the inner end of the bore functioning as a stop to limit the opening movement of the valve member. The extension 5l has an interiorly screwthreaded bore l(i3 extending-axially inwardly from its outer -end and terminates short of the inner end of the bore 62. A spring retainer,A

64 is slidably mounted at the upper end of the lower portion of the extension 6| and has a latber. The retainer member has' a transversely disposed tongue 51 slidably mounted in slots pro-r vided on diametrically opposite sides of the ad jacent extension which prevents relative rotation. An exteriorly screwthreaded plug 68 is threadably mounted in the .bore 63 and its lower end abuts the tongue, axial movement of which varies the tension of the spring and the pre-loading of the valve member. An adjustable member comprising a depending pin 69, of square cross sec tion or other non-circular shape, slidably nts in a similarly shaped opening provided in the plug 58 for affording axial movement of the latter and i has a circumferential ange 10 at its upper fend rotatably engageable with the outer adjacent face of the extension.` A head 1I. is formed at the outer side oi theL fiange'andhas an entrant slot to accommodate a screw-driver or other tool. ailording adjustment.

A securing nut 12 is threadably mounted on the end of the extension and adaptable forengagement with ange for securing it after proper adjustment of the spring. The cap portion 59 has an interiorly screwthreaded opening above the diaphragm adapted to receive a screwthreadedjplug 12 having a small opening 13 therethrough aiording communicationwith the atmosphere to render the valve secures the cap to the lower the valve heads v relatively as .and a valve head 11 'at its upper end.4 the upper marginal portion being securedbetween the adjacent spaced discs |51. The lower end of the bellows abuts the upper face of the disc |46 and a washer |55 of suitable diameteris disposed on the inner side of the bellows to retain the adjacent portion of the bellows therebetween. An upwardly disposed pin |5| has a disc |58 at its lower portion resting upon the washer |58 and its lower end projecting through aligned opening in the washer, bellows, disc, and cup-shaped member, end being upset at |53 to secure the members in rigidly assembled relation ior unitary movement. The relative positions of the corrugations is maintained by an internally disposed metal ring |80 at the peak and an externally disposed metal ring 6I at the valley or bottom thus preventing collapse oi the bellows from either a negative or positive pressure.

A by-pass for fuel, capable of operation independently of the fuel pump, has to be provided and in the present instance it is incorporated in the pump structure. The transverse partition 31, in the bell-shaped housing 34, is provided with transverse openings 14 spaced apart more clearly shown in Figures 3 and 4. Each of these openings is provided with a sleeve 15 fitted tightly in the opening anda laterally extending circumferential ange abutting the under side of the partition. The inner lower edge is beveled to provide a valve seat is adapted for engagement with the seat to control the ow of the fuel thereby. The valve head has an outwardly ex-Y tending stem 18 slidably mounted in a dependlng tubular extension 19 formed upon a disc 80. A coil spring 8| encircles the stem and tubular extension, having one end seated upon the upper face of the valve head and other end seated against the adjacent face of the disc to effect The iiange 1-0 has downwardly extending fingers 82, disposed in` spaced relation relatively the valve seat? and the' lower ends are bent over into securing engagement with `the underside or the disc 80 to maintain proper relation and ex' upon the valve head to in closed position. While two -by-pass valves are shown, any desired number may be employed depending upon the displacement requirements. It will be noted that 11 are so arranged that they resubjected to the pressure of be unseated when fuel into the inlet side ert a spring prassure normally maintain it main closed when Y the return fuel but will is introduced, under pressure, of the pump as by a wobble passing of the fuel tothe outlet side of the pump.

As previously pointed out the pump is adapted for operation in both directions and the housing 34 is mounted as shown inthe drawings, when the rotor rotates in a clockwise direction as indicated by the arrow in Figure 2 If pump affording by.

|58 is substituted for the diaphragm.

rotation of vface 81 formed upon the rotor in the opposite direction is desired, the housing 34 is removed and its position reversed 180 without the necessity of changing any of the relief and by-pass valves.

Rotation is imparted to novel manner as more The outer extension |1 has a non-circular opening 83 extending axially inwardly thereof, in the present c ase hexagonal, to receive a similarly shaped projection 04 axially disposed on one side of a metal seal disc 85. The inner marginal portion of the disc is machined smooth to provide a seal face 86 rotatably engageable with a seal the adjacent outer side of the outer bearing member i3. A projection 88 extends axially outwardly on the opposite side of the disc 85 and is of non-circularshape, square in the present case. The plug 23 has a central bore in which a driven shaft 80 is rotatably disposed, the vided with a toothed pinion 0|. The bore 89 is of enlarged diameter at its inner end to provide an annular shoulder 82 on which a rubber ring the pump rotor in a 5l rests. A bronze sleeve 04 loosely encircles the adjacent portion of the shaft 80 and has longitudinal extensions 85, on diametrically opposite sides, slidably mounted in aligned recesses in the adjacent portion of the plug, thus preventing relative rotation. The sleeve is further provided with a laterally extending circumferential ilange 01 the outer face of which is engageable with the rubber ring to form a. uid seal. The inner end of the shaft 80 has a laterally extending circumferential ange 81, the outerfaceof which is machined forrotary engagement with the inner adjacent face of the sleeve ilange 96. The end of the shaft 80 iscounterbored axially inwardly to conform with the shape of the outer projection 88 in which it is drivingly mounted and a coil spring 88 is disposed within the bore ,and has one end seated upon the adjacent end of the projection 04 and its opposite end seated at the bottom of the bore to exert a separating force sufiicient to eectively maintain the fuel seal disc 81 and oil seal ilange 01.in operative sealing relation.

.At the open end of the housing are a plurality of radially extending arcuate projections 09 in relative spaced relation about the axis `of the bore l0 and the plug 28 has s, plurality of recesses |00 adjacent the outer end of the bore, in spaced relation relatively land preferably of a -diiferent number than 'the number of projections 08. A locking plate |02 has its outer end disposed between a selected, pair of adjacent projections 80 and its inner end bent inwardly and disposed in the adjacent recess |00, a screw |02 removably securing the plate against displacement after proper adjustment. The inner end of the housing i0 is' provided with a lateral flange |08 having transverse opening |04 at its corners by which the pump is adapted gine pad or other support. .Tapped openings|05 are provided at the outer face of the ilange and eways |05 communicate with a-peripheral oil groove |01 formed uponthe outer wall of the plug 28. A passageway |08 is provided in the plug and communicates at its outer end with the groove |01 while its inner end communicates with an oil groove |00 formed upon the inner peripheral wall of the bore 80 outwardly ofthe sleeve. This aiIords for suitably drawing off excess oil passing from the engine pad irrespective of the position in which the pump may be mounted.

In the operation o f thepump, the driven pinclearly shown in Figure 1.

outer end of the shaft being profor mounting upon the enthrough a selector valve and the outlet opening h t h, said v lv member bein of mel t ere hmug a e gfr ing, the bottom of the -bore being normally spaced from the adjacent end of said 'pin but passageway and aording improvement of. said 2,851,817 ion is drivingly connected with the engine, usually directly, andzthe pump rotor'is therefore, rotated at substantially the same speed. The fuel inlet opening is connected with the fuel tanks is connected with the carburetor. With the use of the new type of high pressure carburetors. itis necessary to provide a small reserve tank for supplyingl the' fuelthereto under air pressure andv it is essential that air be pumped by the rotor to maintain the desired air gpressure during that period when the selector valve is being moved from an emptied tank to a full tank. This is effectively afforded by the sealing characteristics of the cooperating shoes and bore described. 15

Also during the operation of the rotor, there is lesser pulsations, due to the particular contour of thebore, especially as compared with pump chambers having lemicon curves or other generatedv surfaces.- by the pump is, of course, far greater than the quantity capable of being handled by the carburetor and the excess is returned to the inlet side -of. the pump through the relief valve. It is weu knownthat the fuel delivered to the oarbu- 25 retor should be under constant pressure and the relief valve is therefore,- adjustable for whatever pressure fis desired.

While I have describedA the preferred embodiment of the invention it is to -be understood that I 'am not to be limited thereto inasmuch as .changes and modifications may be resorted -to without departing from the spirit of the invention as dened in Atheappended claims. f,

- What isv claimed is:

1. A fuel pump comprising: a housing having a fuel inlet opening and a fuel outlet opening therein; pumping means'in said housing for I drawing fuel into said inlet opening and disv4,0

charging the same under pressure from said outlet opening; and fuel relief means affording return of excess' fuel from said outlet opening;

to said-inlet opening through a communicating passageway in said housing including, a valve' 4 member movablymountedin said housingand having a valve head operatively-associated with said return passageway for controlling tlie flow further provided with a pair of laterally extending circumferential flanges disposed rela. tively inaxial spaced relation; a pair of annular members mounted on said housing and having their inner marginal portionsin axial spaced Y relation relatively, the inner peripheral edge 5 of the outer annular member being in closely spaced relation with respect to theouter periph@ A eral edge of the outer flange; a flexible annular shaped diaphragm of .impervious material lcaving its inner marginal portion secured between the adjacent spaced anges and its outer marginal portion secured between the adjacent spaced an-A nular members, the' intermediate portion having an inwardly extending loop of relative'larger size'than the-spacing between the adiacent edges 6 vof the outer annular member and outer flange Atoprevent reversalthereof, the looped portion effectively sealing the outer side of the return elated with vsaid valve The quantity of fuel pumped 20 sure conditions einstlng mountedin said housing and operatively assomember for pre-loading the same whereby said valve headv is normally maintained in closed position; and means for 5 varying the pre-loading eected by said resilient y means.

2. -A fuel pump comprising: .a housing having a fuel inletopening and a .fuel outlet opening therein;

drawing fuelvinto said inlet opening and discharging the same under pressure from said outlet opening; and `fuel rellef'means aifordingreturn of excess fuel from said outlet opening to said inlet opening through a communicating passageway; in said housing including, a valve e member movably mounted in said housing and having a valve head operativelyassociated with said return passageway for controlling the flow of fuel therethrough,`said valve member being further provided with -a pair of laterally extending circumferential flanges disposed relatively in axial spaced relatiom-a pair of annular members mounted on said housing and having their inner marginal portions in axial spaced relation relatively, the inner peripheral edge ofthe outer annular member being in closed spaced relation with respect to the outer peripheral edge of the outer flange; a exible annular shaped dia- 3 phragm of impervious material having its inner marginal portion secured between the adjacent spaced flanges and its outer marginal portion secured between the adjacent spaced annular members, the intermediate portion having an inwardly extending loop `of relatively larger size than the spacing betweenthe adjacent edges of the outer annular member and outer flange to prevent reversal thereof, the looped portion effectively sealing the outer side of the return passageway and affording movement of said valve member; the effective pressure area -of said valve head being substantiallyjequal to the effective area of said flanges for substantially balancing said valve memberregardless of pres-` projecting pin slidably mounted: in aA bore provided in the adjacent portion of said'housproviding a stop thus 4limiting the opening movement of said vaIVe'head; a coiled spring disposed within said housing. and having' its inner end 5 seated on the adjacent ange of 'said valve member for normally maintaining said valve headin closed position: a sleeve slidably but non-rotat- -ably mounted. at the outer portionof the housing and disposed coaxially within the -outer por o tion of. said spring, said sleeve having a laterally extending ange against whichl the outer end of said spring is seated; andmeans operatively associated with said sleeve for effecting axial movevment thereof to vary the spring tension.

' 3; A fuel pump comprising: a housinghaving a fuel inlet opening and'a;fu el outletopening therein; pumping means in" said" housing for drawing fuel vinto said `inlet opening and-discharging the same under pressure from said* l outlet opening; andfuel relief means adording return of excess fuel vfrom said outlet opening to vsaid inlet opening through a communicating passageway insaid housing including,` a valve member'movably mounted in said 'housing-and- -having a valve head operatively associated with et the inlet opening to., l which both are subjected; said valve member being further provided with an outwardly said return passageway for controlling the flow of fuel therethrough; a flexible disc-like annular shaped diaphragm of impervious material having its outer marginal portion sealingly connected to said housing and.its inner marginal portion sealingly connected to said valve member, its intermediate portion being looped to afford unrestricted movement of said valve member and to effectively seal the outer side of said return passageway; means operatively associated with said diaphragm for preventing reversal, of said looped portion and effecting a pressure area balancing of the valve member unaffected'by the pressure conditions existing at the inlet opening; resilient means mounted in said housing and operatively associated with said valve member for pre-loading the same whereby said valve,head is normally maintained in closed position; and means for varying the pre-loading effected by said resilient means.

4. A fuel pump comprising: a housing having a fuel inlet opening and a rfuel outlet opening therein; pumping means in said housing for drawing fuel into said inlet opening and discharging the same under pressure from said outlet opening; and fuel relief means affording return'l of excess fuelfrom said .outlet-opening to said inlet opening through a communicating passageway in said housing including, a valve .,1 `member movably mounted in said housing and having a valve head operatively associated with -said return passageway for controlling the flow of fuel therethrough; a flexible disc-like annular shaped diaphragm of imperviousmaterial having its outer marginal portion sealingly connected tosaid housing and its inner marginal portion sealingly connected to said valve member, its intermediate portion being inwardly looped to afford unrestricted movement of said valve member and to eifectively seal the outer side of said return passageway; means operatively associated with said diaphragm for preventing reversal ofrsaid looped portion and effecting a pressure area balancing of the valve member unaffected by the pressure conditions existing at the inlet opening; cooperating means on said housing and valve member for limiting the opening movement of said valve head; resilient -means mounted in said housing and operatively associated with said valve member for pre-loading the same whereby said valve head is normally maintained in closed position; and means for varying the pre-loading eiiiected by said resilient means.

6. A fuel pump comprising: a housing having a. fuel inlet opening and a fuel outlet opening therein; pumping means in said housing for drawing fuel into said inlet opening and dis- 'charging the same under pressure from said outlet opening; and fuel relief means affording return of excess fuel fromsaid outlet opening to said inlet opening through a communicating,

passageway in said housing including, a valve member movably mounted in said housing and having a valve head operatively associated with said return passageway for controlling the flow of fuel therethrough; a flexible disc-like annular shaped diaphragm of impervious material having its outer marginal portion sealingly connected to lsaid housing and its inner marginal portion sealingly connected to said valve member, `its Yintermediate portion being inwardly looped to afford unrestricted movement of said valve member and to eifectivelyseal the outer side of said return passageway; means opera- Y tively associated with said diaphragms for preiooped 'to afford unrestricted movement of said valve member and to effectively seal the outer side of said return passageway; means operatively associated with said diaphragm for preventing reversal of said looped portion and effecting a pressure area`balancing of the valve member unaffected by the pressure conditions existing at the inlet opening; a coiled spring disposed in said housing and having its inner end seated on said valve member; a sleeve slidably but nonrotatably mounted in said housing and disposed in the outer end of said spring, said sleeve having a laterally extendingange aording a seat for the outer end of said spring; and means operatively associated with said sleeve for effecting movement of the latter whereby `said spring may be desirably tensioned for normally,- mainj taining said valve head in .closedpcsitiom 5. A fuel pump comprising: a housing having a fuel inlet opening and a fuel outlet opening therein; pumping -means in said housing for drawing fuel into said inlet opening and discharging the same under pressure from said outlet opening; and fuel relief means affording .return of excess fuel from -fsaid outlet opening to said inlet opening through a communicating passageway in said housing'including, a valve member movably mo having a valve head operatively associated with said return passageway for controlling the flow of fuel'therethrough; a exible disc-likeannular shaped diaphragm of impervious material having its o ter marginal portion sealingly connected to said housing and its inner marginal portion sealingly connected to said valve member, its intermediate portion -being inwardly venting reversal of said looped portion and effecting a pressure area balancing of thevalve member unaffected bythe pressure conditions existing at the inlet opening; said housing having an integral projection the inner end of which is spaced from but adapted for engagement with said valve ymember for limiting the opening movement of said valve head: a coiled spring disposed in said housing and having its inner end seated-on said valve member; a sleeve4 slidably but non-rotatably mounted on said pro' jection and disposed in the outer end of said spring. said sleeve having a laterally extending flange affording a seat for the outer end of said ted in said housing and spring; 'and means operatively associated with said sleeve for eifecting movement of the latter whereby said spring may be desirably tensioned Y for normally maintaining said valve head in closed position. t

'7. A fuel pump comprising: a housing having a fuel inlet opening and a fuel outlet opening therein; pumping means in said housing for drawingv fuel into said inlet opening and dischargingthe same under pressure from said outlet opening; and fuel relief means aiording return of excess fuel from said outlet opening to said inlet opening through a communicating passageway in said housing including, a valve member movably mounted in said housing and having a valve head operatively associated with said return passageway for controlling the flow of fuel therethrough', said valve member being further provided with a pair of laterally extending circumferential flanges disposed relatively in axial spaced relation; a pair of annular members'mounted on said housing and having their with respect to the outer peripheral edge of the outer ange; a ilexible annular shaped diaphragm of rubber material having its inner marginal portion secured between the adjacent spaced ilanges and its outer -marginal portionV secured between the adjacent spaced annular members, the intermediate portion having an inwardly extending loop of relatively larger size than the spacing between the adjacent edges of the outer annular member and outer ange to prevent reversal thereof, the looped portion effectively sealing the outer side of the return passageway and affording movement o'i' said valve member: the eilective pressure area of said valve head being'substantially equal to the effective area of said anges for substantially balancing said valve member regardless of pressure conditions existing at thel inlet opening to which both are subjected; ,resilient means mounted in said housing and operatively associated with said valve member for pre-loading the same whereby said valve head is normally maintained in closed position; and means for varying the pre-loading effected by said resilient means.

8. A fuel pump comprising: ahousing havinga fuel inlet opening and a fuel outlet opening therein; pumping means in said housing for drawing fuel into said inlet opening and discharging the same under 'pressure from said outlet opening; and fuel relief means affording return of excess fuel from said outlet opening to said inlet opening throughv adcommunicating passagewayin said housing including, a valve member movably mounted in said housing and having a valve head operatively associated with` said returnpassa'geway for controlling the ilow of fuel therethrough, said valve member being further provided with a pair of laterally extending circumferential anges disposed relaginal portion secured' between Jhe adjacent spaced flanges and its outer marginal portion secured between the adjacent spaced annular members, the intermediate portion having an inwardly extending loop of relatively larger size in the adjacent portion of said housing, the` bpttom of the bore being normally spaced from the adjacent end of said pin but providing a stop thus limiting the opening movement of said valve head; a coiled spring disposed within said housing and having its inner end seated on the adjacent ilange of said valve member for normally maintaining said valve head in closed position; a sleeve slidably but non-rotatably mounted at the outer portion `of the housing and associated with said sleeve for effecting axial movement thereof to vary the springtension.

y JAMES 4P. JO'HNSON.