US2625113A - Fuel pump - Google Patents

Description

Jan. 13, 1953 K. I. ROBINSON ETAL FUEL PUMP 1 2 SHEETS-SHEET 1 Filed June 18, 1949 K ENTOR.

Jan. 13, 1953 K. 1. ROBINSON ETAL EUEL PUMP 2 SHEETS--SHEET 2 Filed June 18, 1949 "m? CH INVENTOR. 6 05/11/50 i BY 67764 C/PE/Q/V/ Patented Jan. 13, 1953 UNITED STATES PATENT OFFICE Kenneth Ii Roliinson and ChesferCiprianii Toledo, Ohio Application June 18, 1949;,SerialiNo. 1005048? 3* Claims. 1.

This invention. relates; to. fuel pumps of. the oscillating-diaphragm type, more. particularly to fuel pumps having flexible, oscillating. diaphragms forming an. expansible. chamber with cooperating air domes for. both inlet. and outlet sides ofthe pump,. exteriorly of the. pump. valves.

Diaphragm pumps for. advancing fueL from. a storage; tank generally positioned. at the-rear. of an. automobile to the carburetor have. been. operated by an. oscillating, arm. connected to the center of thediaphragm,.the. arm beingoscillated by a cam on thecam. shaft. operating. the. valves of. the engine. Alost motion -conne.ction.is,-provided. between the oscillating. arm and; the. diaphragmto provide apower suction stroke and a spring-urged feed stroke. so: that. the fuelis delivered. to the. carburetor. at a. predetermined maximumpressure determined by thaspring urging the. diaphragm during the feed portionofthe stroke. However, the. delivery under. the. usual conditions is not. as. smooth as; could be desired and. the. present invention provides a means whereby the delivery is facilitated andimproved to thereby improve. the performancerof. therautomobile.

It is; therefore, a principal object of. this invention to facilitate and improve. the; delivery of. fuel to the carburetor of an automobile by means of an improvediuelzpump.

It-is a further object. of this inventionto improve and cheapen the construction of. anautomotive fuelpumpr It. is. afurther object of this invention to: improve the delivery of a fuel pumpof. an automobile by providing a novel air" dome. construction cooperating withiboththe. inlet and outlet sides of. the pump;

Qther. objects; and advantages of: this invention relating to the arrangement, opera-tioniand function. of. the related. elements on the; structure, to various details; of construction-Jo; com;- binations. of: parts and to economics ofi manu;- facture, will be; apparent: to those skilled. int-he art. upon consideration of the following. description and. appended.- claims,. reference. being: had to the. accompanying drawings. forming: a-. part of. this specification. wherein like: reference: ch31?- acters: designate: corresponding parts in the: sevsoral-views;

Fig. I- is an elevational view;,partlyimsection, of. a pump incorporating; the invention;

Fig: II-isa bottom plan view'otEigzlr Fig. 111* is. a sectional elevation taken; along line 3-3 of. Fig..I; and:

Fig; IV is. a: topplan View; of the lower;- east:- ing of the pump.

Referring, now to; the: drawings; particularly to Figsd 111;. a. fuel: pump: suitable;- for an automobile is shown having; an upper: casing member [0, in which is positioned an oscillating lever l2, preferably of channel shape,. adapted to. cooperate at one end. with its web. witha cam I lv (Fig. III). positioned on the: camshaft of the automotive engine and at. its other. end with. a headed stem t6. attached to. the center of ads);- iblediaphragm. I BT. centrallocation on'a pinz'fljournaledin the housing IE3, and is urged in. a clockwise. direction about the pin 20 against the lower. side of the cam M by a. spring 22,. which is. anchored. on a projection on. the casing at one. end.- and'. acts against.v a clip 24. also. pivoted. on the. pin. 201 as shown. The casing this. attached to-the engine block. (notshown). by boltsin apertures-ifi formed in avertical flange 2B whichi'sprovided. with a flat. forward. face. 301 to. fit. against, a pad on the engine bl'ock,. aseal. being providedby a gasket ring. 32,. seated. in. a circumferential; groove 38 in thenface 31L The. casingmem'ber llllis provided. witha dividiing wall 36 pierced. by fiangedl aperture: 38; through which. extends. the. headed. stem. It to cooperate with the diaphragm [8; The. upper chamber formed by thewall. 36 houses the lever l2 and communicates. with the. crank. case. of. the engine. by an aperture. 40, through. whichv the lever extends. to cooperate. with. the cam 14; In this way, oil. may enter. the. upperv chamber. of the casing from the crankcase. to lubricate the moving, parts. To. prevent egress of. the: oil. from the chamber. through. the aperture. 3.8, a. gasket 42 is provided. to embrace the stern l6 and ex.- tend. a slight. distance. above the floor. of the chamben. The lower. end seated by an. out.- wardly-extending flange. against. the lip of. the aperture 3.8. by a cup-shaped. member 43 as. will be. described hereinafter...

Below. the. dividing wall. 3 6,. the. casing. III is provided. with an=open. chamber 45;..into. which the stem 1-6 extends to. cooperate, with the. diaphragm [8,; which extends across. the open end of. the; casing. L0 to. cooperate. with a horizontal flange. 46,.- against. the: lower. face. of which. the diaphragm I8 is adapted to be: clamped by a lower casing member it having. a. complementary flange. 55-. by screws 52v as. shown. The; chamber 44. is vented to. the atmosphereby an aperture 54 in. the.v casing Ill immediately above the diaphragm wr The diaphragm. I8 is. of laminated construction. such as..is. well. known. inthe: artcomprising at least three plys; of impregnated. flexible. fabric held. together atacentral location by, two plates fifi-rivetedon theend ofan enlarged portion 58 formed onthe: bottom. end ofthe stem I16, and also clamped together at their. perimetral edges between the flanges? 46- and- 50 through the binding actionof the: screws-521 The diaphragm. has a' further function: of sealing. the. air." dome chamtbers:as will be describedihereinafteir.

Thelever I2. is pivoted. at. a-

The diaphragm l8 closes the bottom of the chamber 44 as has been pointed out before, and also forms a distendable, movable wall for a pumping chamber 66 formed by the cooperative relation between the diaphragm and the lower casing member 48. The diaphragm is urged downwardly to collapse the pumping chamber 60 by means of a pair of concentric helical springs 62 and 64, the larger of which is anchored on a flat portion 66 on the lower side of the division wall 36 in the chamber 44, being positioned concentric with the stem 16, and seated at its other end on the upper plate 56 to urge the diaphragm downwardly. The smaller inner spring 64 is also seated on the upper plate 56 but is anchored on an outwardly-extending flange 68 on the cupshaped member 43 positioned around the flange of the aperture 38 to hold the gasket 42 in position. The spring 64 resiliently urges the member 43 upwardly and seals the flange of the gasket on the lip of the flange of the aperture 38 to prevent oil seepage into the chamber 44.

The upper casing member is conveniently made as a die casting, formed in a mold with retractable inserts, one insert forming the upper chamber by being withdrawn laterally through the aperture 40, and a second insert forming the chamber 44 by being withdrawn at right angles to the first. The parting line for the mold is vertical with the member as shown in Fig. I.

The conformation of the lower casing member 46 is best understood by viewing Fig. IV which is a plan view thereof. The pumping chamber 60 is formed in a central location, and is flanked on either side, preferably at right angles to the lever 12, by open-ended recesses 10 and H which are of relatively large volume, and communicate at their lower ends with inlet and outlet passages 12 and T4 to form air domes to cushion the flow of fuel through the pumping chamber 66. These air domes will be described in further detail hereinafter. The diaphragm 18 which comprises the deformable wall and volume-changing member of the pumping chamber forms a seal between the flanges 46 and 56 on the upper and lower casing members respectively, the upper flanges being provided with lateral extensions 46A and 46B to cover the open-ended recesses 10 and H respectively, with the diaphragm positioned therebetween to form seals at their open ends. These elements are all located in planes, so that the screws 52 in the flanges 46 and 50 are pulled down, the diaphragm is compressed to form a seal. This seal comprises the closing off of the pumping chamber 66, and also the closing off of the open ends of the recesses I6 and H, so that an air volume may be trapped in the air domes to form a resilient cushion for the flow of fuel through the pumping chamber.

The pumping chamber 60 is proportioned to the maximum excursions of th diaphragm [8 which is controlled by the throw of the cam I4, so that the greatest possible volumetric change may occur with the full oscillation of the diaphragm as compared with the initial volume of the pumping chamber. In other words, it is desirable to be able to collapse a maximum percentage of the volume of the pumping chamber every full stroke as is consistent with ample clearance to give a maximum compression ratio. It has been found that a compression ratio of approximately two to one is preferred. This is highly ad vantageous in the event of an air lock in the pumping system. In order to carry this into practice, the pumping chamber is made shallow in 4 depth and is provided with a recess 16, in which the inlet and outlet valves 18 and 86 are positioned. The floor of the recess 16 is made slightly oblique, tilting downwardly from the outer longituoinally disposed ends and forming a low point at a central location adjacent a screw 82 which i threaded into the casing 48 between two wells '84 and 86 which open into the recess 16 at the upper ends and form valve seats 88 and 96 therewith.

The inlet and outlet valves 18 and are of generally similar conformation, comprising a flanged seat 92, a valve plate 94 seated on one side thereof, a spring 96 and a spider 98 as is well known in the art. The inlet valve '18 is provided with a dome-shaped filtering screen I00, facing the direction of fuel flow to separate from the fuel particles of foreign matter before it enters the pumping chamber. The flange 92A of the respective seats rest against the termination edge of the Wells 84 and 66 respectively, and are provided with a unitary gasket I02 extending across the recess 16 to provide a seal. A double armed spring member 104 having a pair of loops, each with a pair of depressed portions resiliently pressing at two points on each flange 92A, urges the inlet and outlet valves against the gasket 102 by the pulling down action of the screw 82, which cooperates with the spring member I04 at a central location. The spring member is given better purchase by the slight angular relation of the inlet and outlet valves as provided by the oblique floor of the recess 16, and is seated against an abutment i06 immediately below the central portion adjacent the screw. The well 86 on the outlet side is provided with an integral fin I08, to prevent reversal of the valves, due to the interference provided with the filtering element I00 on the inlet valve, so that it cannot be positioned in the outlet well.

Adjacent the bottom of the wells 84 and 86, transverse bores are provided forming the inlet and outlet passages 12 and 14, which, at their outer ends, are provided with threaded sections 12A and 14A for convenient connection into the fuel lines of the automobile to which the pump is applied. Adjacent an intermediate location between the threaded portions 12A and 14A, conical interconnecting passages 10A and HA are provided between the inlet and outlet passageways 12 and I4, and the recesses 10 and 'H, located directly above. The constricted portion of the conical passageways 70A and HA communicate with the upper portion of the passageways 12 and i4 and tend to separate air bubbles which are often to be found in the fuel flowing through the pump. The recesses 10 and H are given volumes at least '75 per cent as great as the maximum volumetric displacement of the pumping chamber to give greater efficiency for the pump by providing an enlargement above the conical passages 10A and HA below the relative position of the valves 18 and 80. It has been found that if the volume of each of the recesses or air domes l0 and H is equal to the maximum volumetric displacement in the pumping chamber, that is, the volumetric change created by the movement of the diaphragm ill from collapsed to fully distended position, an efficient pump is obtained. Due to the trapped air in these air domes, the flow through the pump is smoother and the pump develops greater efficiency. The air domes are self-cleansing and remain eflicient during sustained operation of the pump.

The lower casing member 48 is preferably made acemre as a die-casting, in which the mold has a h rizontal parting linewith the casing member as shown in Fig. II. Retractable inserts withdrawn from the upper side with. the casing member 48 as shown in Fig. I are used to form the recesses TB and H including their conical sections which form the air domes. in the completed pump, as well as to form the pumping chamber: 60, the valve recess 16, andthe wells at and 86, including the fin H38. formed in the. well 861.

The pump operates with a power suction stroke as provided by the cam I4 oscillating the lever [2 to thrust the diaphragm I8 upwardly by means of the stem IE against the springs 62 and 64. The feed stroke is spring-urged with the power being provided by the compressed springs 62 and 64 at the end of the suction stroke. When fuel is not demanded by the carburetor of the car, with which the pump is being used, it will remain in the pumping chamber 68, so that no feed stroke will be had, but the diaphragm I8 will remain at full distended position by the action of the lever l2, which returns the diaphragm to full stroke position on the suction stroke with each revolution of the cam. The interaction of the headed stem 16 and the bifurcated end portion of the lever l2, which form a seat for the head of the stem, provides a lost motion connection to attain the above-described interaction of the parts.

It has been found that large air domes are essential on both the outlet and inlet sides to have this pump operate at its greatest efiiciency and it has been a problem to provide sufllciently large air domes within die castings which can be made with economy and speed on a production line. The pump disclosed hereinbefore has very desirable characteristics for use with the fuel systems of modern automobiles.

It is to be understood that the above detailed description of the present invention is intended to disclose an embodiment thereof to those skilled in the art, but that the invention is not to be construed as limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of being practiced and carried out in various ways without departing from the spirit of the invention. The language used in the specification relating to the operation and function of the elements of the invention is employed for purposes of description and not of limitation, and it is not intended to limit the scope of the following claims beyond the requirements of the prior art.

What is claimed:

1. In a pump, a flexible diaphragm, a lost-m0- tion driving connection for the diaphragm cooperating with a continuously rotating cam means for displacing the diaphragm providing a positive suction stroke for the diaphragm, resilient means cooperating with the diaphragm adapted to be compressed by the lost-motion driving connection during the suction stroke to provide a feed stroke for the diaphragm upon the return stroke of the driving connection, a pump casing positioned below the diaphragm comprising a one-piece die casting having a shallow central recess to form a pumping chamber and a pair of deep flanking recesses to form air domes, all of said recesses being sealed by the diaphragm, a valve recess in the pumping chamber, inlet and outlet ports in the casing passage-ways in the pump casing including deep depending wells connecting the valve recess in the pumping chamber with inlet and outlet ports in the pump casing,

valves positioned in said. valverecess; the pump.- ing chamber being proportioned with reference to the diaphragm displacement including? the valve recess to give a. two to one compression ratio, said flanking recesses in the casing being in parallel relation to the. depending wells. and. in communication with the passage-ways leading to said inlet and outlet ports by' means of. conical passages in the casing which communicate with enlargements in the flanking recesses at a level below the valves whereby air domes are provided having a volume at least 75 per cent of the displacement of the pumping chamber.

2. In a pump, a flexible diaphragm, a lost-motion driving connection for the diaphragm cooperating with a continuously rotating cam means for displacing the diaphragm providing a, positive suction stroke for the diaphragm, resilient means cooperating with the diaphragm adapted to be compressed during the suction stroke by the lost-motion driving connection to provide a feed stroke for the diaphragm upon the return stroke of the driving connection, a pump casing positioned below the diaphragm comprising a onepiece die casting having a shallow central recess to form a pumping chamber and a pair of deep flanking recesses to form air domes, all of said recesses being open in a plane on the top side of the casing and adapted to be sealed by the diaphragm, inlet and outlet ports in the casing, a valve recess in the pumping chamber, passageways in the casing including deep depending wells connecting the valve recess with inlet and outlet ports, valves positioned in the recess, the pumping chamber being proportioned with reference to the diaphragm displacement including the valve recess to give a two to one compression ratio, said flanking recesses in the casing being in parallel relation to the depending wells and in communication with the passage-ways leading to said inlet and outlet ports by means of conical passages in the casing which communicate with enlargements in the flanking recesses in the easing at a level below the valves whereby air domes are provided having a volume at least 75 per cent of .the displacement of the pumping chamber.

3. In a pump, a flexible diaphragm, a lost-m0- tion driving connection for the diaphragm cooperating with a continuously rotating cam means to displace the diaphragm providing a positive suction stroke for the diaphragm, resilient means cooperating with the diaphragm adapted to be compressed during the suction stroke by the driving connection to provide a feed stroke for the diaphragm upon the return stroke of the driving connection, a pump casing positioned below the diaphragm comprising a. one-piece die casting having a shallow central recess in its upper surface to form a pumping chamber and a pair of deep flanking recesses also opening in the upper surface of the casing to form air domes, all of said recesses terminating in a plane and adapted to be sealed by the diaphragm, a valve recess in the pumping chamber, inlet and outlet ports in the casing, passage-ways in the casing including deep depending wells connecting the valve recess with inlet and outlet ports, valves positioned in the recess, one of said valves positioned on the inlet side being provided with an integral filtering screen extending into its depending well, the pumping chamber :being proportioned with reference to the diaphragm displacement including the valve recess to give a two to one compression ratio, said flanking recesses in the casing being in parallel rela- 7 8 tiori to the depending wells and'in communication REFERENCES CITED with the passage'ways leading to said inlet and The following references are of record in the outlet ports by means of conical passages in the file of this patent: casing which communicate with enlargements in the flanking recesses at a level below the valves 5 UNITED STATES PATENTS whereby air domes are provided having a volume Number Name Date at least 75 per cent of the displacement of the 2,148,957 Morris et a1 Feb. 28, 1939 pumping chamber. 2,203,464 Harry June 4, 1940 KENNETH I. ROBINSON. 2,287,841 Tabb .a June 30, 1942 CHES'I'ER CIPRIANI. 10 2,405,466 Tabb Aug. 6, 1946

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