US2782719A - Fuel pump - Google Patents

Description

Feb. 26, 1957 Filed July 7, 1954 B. J. GEORGIAS FUEL PUMP 3 Sheets-Sheet 1 J Gear Ta/5 www Peb, Z6? 1957 B. J.' GEORGIAS FUEL PUMP 3 Sheets-Sheet 3 -Filed July 7,. 1954 nited Sttes Patent FUEL PUMP Basile J. Georgias,'Boston, Mass.

Application July 7, 1954, Serial No.'441,823

4 Claims. (Cl. 103'-'42) This invention relates to fuel pumps for internal com- Vvbustion engines and particularly to pumps for delivering According to lthe present invention the apparatus has -afsupplychamber for connecti-on to a source of supply and adelivery conduit for connection to the engine, together with meansfor pumping fuel from the 4supply chamber to the delivery conduit, a relief conduit leading from vthe delivery conduit vto the supply chamber and a relief valve in the relief conduit to keep the pressure in the delivery conduit from rising above the predetermined pressure for which the relief valve `is set. Preferably fthe supply chamber is .a vacuum chamber, the relief valve is located inside this chamber and a portion of the wall of the chamber is transparent so that the setting oi thevalve may Abe observed without 1 openingthe chamber. vIn .thepreferred embodiment the chamber has a movable cover Ato .afford 'access to the adjusting means, the coverhaving a transparent portion 1 through which the 4setting of the valve may be observed without removing the cover.

11n another aspect the apparatus comprises .a hollow "bracket fitting the side of a crank-case with means extending through the hollow bracket for driving the pump- .ing means by the engine.

'In still another aspect the apparatus includes an air Thus the fuel pump may :be `mountedon "the-bracket alone or the air pump Amay be mounted on the bracket and the fuel pump -mounted 4on the air pump.

ln either case the p'urnpsl are above` the oil level in the crank'cas'e so that they do'rnot become fouled 'by oil through the aforesaid hollow bracket.

'For the purpose of illustration a typical embodiment Vdf the invention is shown in 'the la-cconlpanying Vdrawings in which '.Fig. 1 is a sectionon lineY V1--11 of Fig. 2;

Fig. 2 is a section on line 2-'2 of Fig.l l;

Fig is a section on line3-3 of'Fig. 2;

Fig. 4'is .a section likeFig. 2 showing yan air pump .mounted between the fuel pump -and the aforesaid .hollow bracket;` l Y y Fig. :5 is .a vertical section through .the relief valve taken on the line 2-2 of Fig. l;

Fig. 6 is a similar view of a modified relief valve;

Fig. 7 is a similar view of another modified `relief valve;

Fig. 8 `is a ysection 'of the'check valve between the pump chamber and the delivery conduit taken on the saine line as in Figs. Zand 5; and

Fig. 9 is a section on line 9-9 of Fig. 8.

The p-articular embodiment of the invention chosen for the purpose of illustra-tion comprises a hollow .bracket l having bolt openings A2 for mounting it on .the side of a crank-case,I a'pump casing comprising upper and lower parts 3 and 4 secured together by bolts extending through openings '6 and `a ltransparent cover secured to the upper part of the casing by means of 'a bail 8 and screws 9. Cltamped between the par-t 3 and cover 7 is a filter 10. Clamped between the upper and lower parts of the casing is a diaphragm. llwhich is urged upwardly by a spring 12 and is pulled down `against the action of the yspring by means of a rod A13 and 4arm 14 pivoted at 16, another rod 17, an arm comprising ftwo parts 18 and 19, and cam 21 on the cam shaft 22 of the engine. The rod 17 is urgedupwardly v'by a spring 23 which holds the arm 19 against thecam 21 either with or vwithout the assistance of the spring 12. The arms 18 and 19 are interconnected by a serrated bolt 24 which interlocks the arms together in lany desired angular rela-tionship, the ends of the serrated bolt being pivc'tally mounted on the .bracket 1 to permitthe arms 8 and y9 to os-v.

cillatebackand forth as a unit in response to the cam 21.. The lupper part 3 of the casinghasa hollow space 26y on its upper side which communicates'wit-h the source of fuel supply through an inlet 27. vAt the bottomvof this: space on one side Iof the casing is a clean-out opening normally closed by a plug 2 8. Projecting up into the: space 26 are two cylindrical anges 29 and 31. Communicating with the interior of the flange 29 is a delivery conduit 32 for connection to the carburetor. Mounted in the bottom of the flange 29 isa check valve 33 whichis shown in detail in Figs. 8 and 9. This valve comprises a 4threaded Anipple having an axial opening 34. vFastfin a recess in the top of the nipple is a ring 36 vhaving .openings .37. The valve comprises a disk 38 covering the opening .37, a headed stem 39 and a spring 41 Iseating-at its upper end against the valve seat 36 'and at its lower endvagainst the head of the stem, thereby .yieldingly to thold the valve 38 against the seat. Threaded into the upper endof the ange 29 is a relief valve'42 describedv hereinafter. Threaded into the flange 31 is another check lvalve 43 simil-ar to the check .valve 33 butfacing in the opposite direction.

As shown in Fig. 5 the reliefvvalve 42 comprises a cylindrical casing 46 having its lower end' threaded .into the angej31 with a flange seating on vthe screen 10. Threaded `into the upper end of the sleeve 46 is a nut 47 having fuel passages 48. Threaded through the-'nut y47 is a stern @and mounted'on the upper end of the stem isa cap -51 which telescopes yover the casing 46 and has a fuel outlet 52. The lower end of the stem 49 is re duced in diameter and fitting over this reduced end is acap 53 secured on .the vstem by a pin 54 extending through slots 56 in thecap. Inside the lcap is a compression spring 57 yieldingly to urge the ball valve 58 against the yseat in the lower-end of the sleeve 46. To adjust the pressure ofthe'spr'inglS? on the valve the capv 51 is turned, the spring :is accurately calibrated and the cap and sleeveare marked :accordingly as shown in Fig. 2 to indicate `the adjustment. Thus the device-affords a micrometer adjustment.

As shown 'in Fig. 5 the lower end of the sleeve 46 is provided with :a cylindrical opening 59 partially closed at its lower end by a perforated ring 61, thereby to cushion any .hydraulichammering which tends to develop.

The modified relief valve shown in Fig. 6 is like that shownin Fig. except in that'the ball valve 58 is replaced by conical valve 62 Iand the anti-hammer space .59 is omitted.

' The modined relief valve shown in Fig. '/"difrerjfrom those shown in Figs. 5 and 6 in the following respects. Clamped between casing 3 and the sleeve 63 is a perforated disk 64 having a conical valve 66. Seating on this valve is a piston 67 having a covering 68 formed of leather or the like. Mounted in a peripheral groove in the piston is a coil spring 69 to press` the sleeve 68 outwardly to make a snug tit. The piston has an axial opening 71 through which fuel may flow when the piston lifts olf the valve-'66 in response to fuel pressure in vthe delivery conduit 32. `NormallyV the piston is held against the valve to prevent liow by means of a spring l72, the pressure of which is adjusted by the micrometer to create a partial vacuum therein. In response to this reduced pressure fuel ows from the supply tank through the inlet 27 into the supply chamber below the screenv 10 and thence upwardly through the screen until it reaches the level L in Fig. 2, whereupon it overflows into the check valve 43. Then when the diaphragm descends it draws fuel past the check valve into the 'pump chamber 73 and on the up-stroke of the diaphragm liquid is forced past the check valve 33 into the delivery conduit 32. When the pressure in the delivery con- -duit reaches the value at which the relief valve 42 is set,

the relief valve opens and enough liquid is by-passed from the delivery conduit 32 tothe supply chamber 26 to keep the pressure from rising substantially above the value at which the relief valveis set.

'In Fig. 4 an air pump 76 is interposed between the fuel pump and the bracket 1, the lower end of the air pump 76 being shaped to t the bracket 1 the same as the fuel pump and the upper end of the air pump being shaped like the bracket 1 to fit the fuel pump. The air pumpV comprises upper and lower parts with a diaphragm 77 clamped therebetween, the diaphragm being urged upwardly by a spring 78.. Mounted in the casing 76 are two check valves 81 and 82, the check valve 81 permitting air to flow upwardly into the chamber 83, but preventing reverse iiow and the check valve 82 permitting down-ow from the chamber 83 to the outlet 84 while preventing reverse iiow. Thus as the diaphragm moves up and down air is pumped through the inlet 86, thence through screen 87, thence into the chamber -82 and thence through the outlet 84. Y

'When` using the air pump 76 the stem 17 is replaced by a longer stem 87, the diaphragm 77 being actuated by a stem 88 extending into an opening in the" pivoted arm 14. M v

In Fig. 4 the cam shaft 89 is shown at a lower level to illustrate how the two arms 18 and 19 may be adjusted 'relatively to each other to accommodate engines of different makes. l

As shown in Fig. 2 the top of the transparent cover increases in thickness from the peiiphery toward the center thereby serving as a lens to magnify the appearance lof the relief valve and other parts in the supply chamber. While onlythe outside surface'is curved in the drawing, of courseit will be understood that either surface or both surfacesmay be convex. A' Y lt should be understood-that the presentrdisclosure is for the purpose of illustration only and thatfthis invention includes allmoditications and equivalents which fall within the scope of the appended claims.

l. For supplying fuel to an engine at a predetermined pressure, a device having a vacuum chamber for connection to a source of supply and a delivery conduit for connection to the engine, a pump chamber intermediate the vacuum chamber and delivery conduit, means associated with the pump for drawing fuel from the vacuum chamber and forcing it into the delivery conduit, a duct leading from the vacuum chamber to the pump chamber, the inlet end of said duct being located above the bottom of the vacuum chamber, a check valve in said duct to check flow from the pump chamber to the vacuum chamber, a check valve between the pump chamber and the delivery conduit to check flow from the delivery conduit to the pump chamber, a relief conduit leading from the delivery conduit to the vacuum chamber, a relief valve in the relief conduit to keep the pressure in the delivery conduit from rising above said predetermined pressure, and means inside the supply chamber for adjusting the relief valve, a portion of the wall of the supply chamber being transparent so that the setting of the valve may be observed without opening the chamber, said portion being substantially flat on one side and convex on the other side so as to magnify the valve setting.

2. For supplying fuel to an engine at a predetermined pressure, a device having a vacuum chamber for connection to a source of supply and a delivery conduit for connection to the engine, a pump chamber intermediate the vacuum chamber and delivery conduit, means associated with the pump for drawing fuel from the vacuum chamber and forcing it into the delivery conduit, a duct leading from the vacuum chamber to the pump chamber, the inlet end of said duct being located above the bottom of the vacuum chamber, a check valve in said duct to check flow from the pump chamber to the vacuum chamber, a check valve between the pump charnber and the delivery conduit to check flow from the delivery conduit to the pump chamber, a relief conduit leading from the delivery conduit to the vacuum chamber, a relief valve in the relief conduit to keep the pressure in the delivery conduit from rising above said predetermined pressure, a removable cover for the supply chamber, and means under the cover for adjusting the relief valve, the cover having a transparent portion through which the setting of the valve may be observed without removing the cover, said portion being substantially fiat on one side and convex on the other side so as to magnify the valve setting.

3. For supplying fuel to an engine at a predetermined pressure, a body having a relatively flat upper surface, seating on said surface an inverted cupshaped cover, sealing means between the surface and cover so that the space under the cover can be used as a vacuum chamber, said body having an inlet andan outlet, a duct leading from the inlet through said surface into -the vacuum chamber, a pump chamber in said body, a conduit extending from the pump chamber through said surface and projectingtinto the vacuum chamber above said surface so that liquid must rise to the level of the upper end thereof before it can flow to the pump chamber, a delivery conduit leading from the pump chamber to said outlet adjacent said surface, a threaded opening through said surface from the delivery conduit, and a relief valve comprising a cylindrical base threaded into said opening and projecting into the vacuum chamber, the base having an upwardly facing valve seat, a valve on the seat, a spring for yieldingly holding the valve on its seat, a stem threaded axially through the base for adjusting the pressure of the spring, and an inverted cupshaped cap fast to the upper end of the stern with its side wall telescoping over .the base so that the telescoping parts may carry cooperating micrometer calibrations, and means for detachably securing said cover, whereby the relief valve may be adjusted by removing the cover accurately to regulatethe pressureY offuel delivered through said v outlet.

4. For supplying fuel to an engine at a predetermined pressure, a body having a relatively at upper surface, seating on said surface an inverted cup-shaped cover, sealing means between'the surface and cover so that the space under the cover can be used as a vacuum chamber, said body having an inlet and an outlet, a duct leading from the inlet through said surface into the vacuum chamber, a pump chamber in said body, a conduit extending from the pump chamber through said surface and projecting into the vacuum chamber above said surface so that liquid must riseY to the level of the upper end thereof before it can flow to the pump chamber, a delivery conduit leading from the pump chamber to said outlet adjacent said surface, a threaded opening through said surface from the delivery conduit, and a relief valve comprising a cylindrical base threaded into said open ing and projecting into the vacuum chamber, the base having an upwardly facing valve seat, a valve on the seat,

a spring for yieldingly holding the valve on its seat, a stem threaded axially through the base for adjusting the pressure of the spring, and an inverted cup-shaped cap fast to the upper end of the stem with its side wall telescoping over the base so that the telescoping parts may carry cooperating micrometer calibrations, and means for detachably securing said cover, said cover being transparent and shaped to serve as a lens for use in reading the setting of said cap.

References Cited in the tile of this patent UNITED STATES PATENTS 2,381,259 Coffey Aug. 7, 1945 2,405,466 Tabb Aug. 6, 1946 2,570,560 Katcher Oct. 9, 1951 2,631,538 Johnson Mar. 17, 1953

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