US2193612A - Pump - Google Patents

Description

March 12, v1940.` R. ALDl-:N

PUMP

original Filed oct. 8, 1952 Patented Mar. 12, 1940 'UNITED STATES PATENT OFFICE PUMP Carroll R. Alden, Detroit, Mich., assigner to Ex-Cell-O Corporation, a corporation of Mich- 6 Claims.

The present invention relates generally to improvements in variable-delivery pumps, and has particular reference to pumps especially adapted for use in fuel injectionV systems and other hy-` One object resides in the provision of a novel l multiple piston and cylinder pump whereineach cylinder is flooded during the entire suction stroke of the piston, thereby preventing cavitation and the formation of vapor.

Other objects andfadvantages will become apparent as the description proceeds.

In the accompanying drawing,

Figure 1 is a pian view of a pump embodying the features of my invention.

Fig. 2 is a vertical axial sectional view taken go along line 2-2 of Fig. l.

Figs. 3, 4, 5 and 6 are transverse vertical sectional views taken respectively along lines 3--3 to 6--6 inclusive of Fig. 2.

While the invention is susceptible of various g5 modifications and. alternative constructions, I

have shown in the drawing and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specic'form 30 disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

Referring more particularly to the drawing,

35 the pump, constituting the exemplary embodiment of the invention, is of the variable-flow metering and distributing type, and is especially suited for pumping volatile liquids, such as gasoline, naphtha and other similar fuels. In its preferred form, the pump comprises a casing 1 which is generally cylindrical in shape, and vperipherally enlarged at one end as indicated at 8. The enlarged portion` 8 is formed adjacent its free end with a peripheral flange 9. To mount (Cl. 10S-173) or pump cylinders, six cylinders I4 to I9 in the present instance (see Figs. 2 to 4), uniformly spaced concentrically about the axial center of the casing. A plurality of radial bores to 25 (see Fig. 5) tapped in their outer ends, are formed in the enlarged portion of the casing l, and open at their inner ends respectively through ports 26 to 3I to the closed inner ends of the cylinders I4 to I9. The bores 20 to 25 are adapted to be connected by means of fittings (shown in Figs. 2 and 5) respectively to the inlet ends of a like number of discharge conduits (not shown). Spring-pressed ball check valves 32 (see Fig. 2 and 5) in the bores 20 to 25 seated against the ports 26 to 3I prevent any back flow of fuel into the cylinders I4 to I9.

The inner end of the enlarged portion 8 of the casing 1 is formed externally with a peripheral notch 33, and in the cylindrical surface of the latter is formed a peripheral groove 34. A seal ring 35 fitted in the notch 33 serves to close the groove 34. Opening through the ring 35 is an inlet line or passage 36 leading from a suitable supply (not shown) of the liquid to be pumped.

A plurality of inlet ports 31 to 42 (see Fig.- 4)My formed in the casing 1 open from the groove 34 respectively into the cylinders I4 to I9.l

Slidably disposed respectively in the cylinders I4 to I9 are a plurality of pump pistons or plungers 43 to 4B. Each pump piston (43 to 48) in its outward or suction stroke is adapted. to uncover the associated inlet port (3l to 42), and on its return or pressure stroke to cut-off the inlet port and force the liquid under pressure in a metered quantity through the associated outlet port (26 to 3|) past the valve 32 into the discharge line. vIt will be evident that theA extent of movement of each piston on its pressure stroke past its inlet portdetermines the volume of liquid metered in each discharge.

Any suitable drive may be provided j for reciprocatlng the pistons 43 to 48 intimedsequ'ence and in timed relation to the engine. In the present instance, thisvmeans comprises a .drive shaft' 49 extending through and journaled in an axial bore formed inl the casing l. The end of the shaft 49 outside ofthe recess I3 has fixed thereon a pinion 5I adapted to be geared vto a suitable power means, suchl asan enginecrankshaft (not shown).A

The other or inner end of the shaft His-formed with a peripheral collar 52 adapted to abut rotatably against the adjacent end lof the casing 1, and beyond the collar is reduced in size and bent at an angle to its axis to provide an eccentric hub 5,3.

The inner raceway of a ball bearing 54 is securedby means of a nut 55 on the hub 53 against a peripheral transverse shoulder 56. 'Ihe outer raceway of the bearing 54 is seated in the inner periphery of an annular concentric swash or wobble plate 51.

Formed in the wobble plate 51 in uniformly spaced relation about the bearing 54 are a plurality of recesses 58, each of which has an internal peripheral flange 59 at its outer end. A plurality of bearing plugs 60 are threaded into the wobble plate 51 at the other ends of the recesses 58, and each plug is formed in its inner end with a concave or semi-spherical bearing seat 6 I The outer ends of the pistons 43 to 48 extend respectively into the recesses 58 and are formed with rounded heads 62 in bearing engagement with the seats 6I. Coiled compression springs 63 seated against the flanges 59 and impinging against the heads 62 serve to hold the latter continuously against the seats 6 I. A cap 64 secured to the end of the casing 1 encloses the wobble plate 51 and associated parts. It will be evident that each of the pistons 43 to 48 has a universal connection with the wobble plate 51, and that upon rotation of the latter the pistons will be reciprocated in timed sequence.

The volume of delivery may be adjusted by shifting the shaft 49 axially to vary the point of cut-off of the inlet ports 31 to 42 by the pistons 43 to 48. Thus, upon adjusting the shaft 49 into its outermost position, as shown in Fig. 2, the pump will deliver at maximum, and upon adjusting the shaft inwardly the volume of delivery will be progressively reduced.

A pump of the character thus far described is subject to the objection, particularly where a highly volatile fuel such as gasoline is handled, that on the suction stroke of each of the pistons 43 to 48, a substantial vacuum is induced in theV associated cylinder, with the result that the liquid in the cylinder tends to vaporze, and that upon uncovering the inlet port the fresh liquid enters with a decided rush. These conditions are not conducive to efficient operation of the pump or of an engine where the liquid is delivered for injection. To prevent same, provision is made to flood each of the cylinders I4 to I9 with fuel during the suction stroke of the associated piston regardless of whether or not the associated inlet port has been uncovered. More particularly, all cylinders whose pistons are on their suction stroke and preferably also those whose pistons are on their pressure stroke but have not cut-off the associated inlet ports are interconnected for the by-pass of liquid. Since some one or more of these cylinders are always in communication with their inlet ports, all of the connected cylinders will be flooded with fuel.

The by-pass means comprises a plurality of passages 65 to 10 (see Figs. 3 and 5)' formed in the body of the casing 1 and communicating respectively with the closed inner-- ends of the cylinders I4 to I9. The passages 65 to 10 open in uniformly spaced relation in a common transverse plane to the periphery lof the bore 50, each passage` preferably being located in a common Aradial plane with its associated punip cylinder.

Formed in the periphery of the drive shaft 49 is a circumferential groove 1I extending through approximately 240. The lead end of the groove 1I is movable into successive communication with the passages 85 to 10 upon rotation of the shaft 49 in a counterclockwise direction as viewed from the right in Fig. 2. The width of the groove 1I is substantially greater than that of the communicating ends of the passages 65 to 10 so that the rotary valve constituted thereby is unaffected by axial adjustment of the shaft 49. The groove 1I has a phase relation to the pistons 43 to 48 such that all of the cylinders except those in which the pistons at any particular time are in the effective portions of their pressure strokes are intercommunicatlng. Thus. as a given piston reaches a predetermined point in its inward movement, namely cut-off at full throttle, the associated cylinder is cut out of communication with others of the cylinders.

To prevent fuel from leaking along the shaft 49 out of the casing 1 to the atmosphere, a labyrinth groove 12 is formed in the periphery of the shaft externally of and in spaced relation to the by-pass groove 1I. The groove 12 opens through a radial duct 13 and an axial bore 14 in the shaft 49 to the interior of the end cap 64. Fuel leaking along the pistons 43 to 48 also enters the end cap 64. A drain conduit 15 connected to the casing 1 and opening through a passage 16 in the latter to the interior of the cap 64 serves to remove any fuel collecting therein.

The shaft 49 as a rotatable element constitutes the drive for the pump, and as a shiftable element constitutes the fuel throttle. Thus, axial adjustment of the shaft 49 is effective to shift the region of reciprocation of the pistons 43 to 48 collectively relative to the inlet ports 31 to 42, and thereby to vary the amount of the discharge, and incidentally the length of the discharge period and the phase relation of the start of each period to the pump cycle.

To provide means for adjusting the shaft 49 axially, the inner raceway of a. ball bearing 11 is rigidly secured thereon within the recess I3. Two shifter shoes 18 pivotally mounted in the arms of a rocking yoke 19 engage the outer raceway of the bearing 11 at diametrically opposed points. The yoke 19 is fixed on a rock shaft 80 journaled in the casing 1 and extending therefrom for external actuation, as for example a reverse self-locking throttle actuator (not shown) disclosed in my aforesaid application.

I claim as my invention:

1. A pump comprising, in combination, a casing, a plurality of pump cylinders formed in said casing in parallel uniformly peripherally spaced rotation, aplurality of pistons respectively recip' rocable in said cylinders, a plurality of fuel inlet ports opening respectively to said cylinders in a common transverse plane and adapted to be covered and uncovered in the reciprocation of said pistons, a plurality of fuel outlet ports opening from said cylinders, a valve bore in said casins', a rotary valvein said bore, a plurality of by-pass passages opening respectively from said cylinders to said valve bore, and means for reciprocating said pistons in uniformly timed sequence and for driving said valve in timed relation thereto to interconnect those of said by-pass passages opening to cylinders wherein the pistons are on their suction stroke.

2. A pump comprising, in combination, a vcas ing having a bore, a drive shaft extending slidably and rotatably through said bore, an inclined bearing on said shaft at one end of said casing, a wobble plate rotatably mounted on Said bearing, a plurality of pump cylinders formed in said one end of said casing in parallel uniformly peripherally spaced .relation, about said shaft, a plurality of pistons respectively reciprocable in said cylinders and extendingfrom said casing.

the outer ends of said pistons being operatively related to said wobble plate, a plurality of fuel inlet ports opening respectively to said cylinders in a common transverse plane intermediate the ends of said cylinders and adapted to be covered and uncovered in the reciprocation of said pistons, means for shifting said shaft axially to adjust the range of reciprocation of said pistons relative to said inlet ports, a plurality of outlet ports opening respectively from the inner ends of said cylinders, a-plurality of by-pass passages opening respectively from said inner ends of said cylinders to said bore in a common transverse plane, and a valve groove formed in said shaft fr rotary movement successively into communication with said by-pass passages in all axial positions of said shaft, said groove extending partially about said shaft and being related in phase to said wobble plate to interconnect all of said cylinders in which said pistons are moving outwardly or said inlet ports are uncovered.

3. A pump comprising, in combination, a casing having a plurality of parallel pump cylinders, pistons reciprocable respectively in said cylinders, means for reciprocating said pistons in timed sequence, each reciprocation comprising a suction stroke and a return pressure stroke, inlet ports opening respectively to said cylinders and adapt-v ed to be uncovered by said pistons in the courself o1' said suction strokes, a plurality ofdiscnarge 1 -ripherally' ports opening respectively from said cylinders,

means for simultaneously adjusting the regionof reciprocation of said pistons in said cylinders relative to said inlet ports, and a rotary by-pass valve automatically operable to connect each cylinder during the suction stroke of the associated piston with some other of said cylinders which is in communication at the time with its associated inlet port.

4. A pump comprising, in combination, a casand means automatically operable to connect each cylinder independently of said inlet ports during the entire suction stroke of the associated piston with. some other of said pump cylinders which is in communication at the time with its associated inlet port.

5. A pump comprising, in combination, a casing having a bore, a drive shaft extending rotatably through said bore, an inclined bearing on said shaft at one end of said casing, a wobble plate rotatably mounted n saidbearing, a plurality of pump cylinders zormed in said one end of said casing in' lparallel uniformly peripherally spaced relation about said shaft, a plurality of pistons respectively reciprocable in said cylinders and extending from said casing, the outer ends of said pistons being operatively related to said wobble plate, a plurality of uld inlet ports opening respectively to said cylinders in a common transverse plane intermediate the ends of said cylinders and adapted to be covered and uncovered in the reciprocation i' said pistons, a plurality of outlet ports opening respectively from the inner ends of said cylinders, a plurality of by-pass passages opening respectively from said inner ends of said cylinders to said bore in a common transverse plane, and a valve groove formed in said shaft for rotary movement successively into communication with said 'by-pass passages, .said grooveextending partially about said shaft andibeing related in phase to said wobble` platejtointerconnect the cylinders in which said L pistons i are moving outwardly.4

- 6., A pumplcomprising, in combination, a casre, a-plurality of pump cylinders verse' 'plane .intermediategthe ends of said cylindersand adapted to be vcovered and uncoveredv in thegjreciprocation of said'pi'ston's, a pluralityofi outlet4 ports opening vrespectively from the iliniaal',V ends of said cylinders, a plurality of by-l -1 passages opening respectively `from said innerfends'oi' said cylinders Vto said bore in a com-1 mon 'transverse plane, a--valve rotatable-in rsaid bore,.andmeans for reciprocating said' pistons,V

are moving outwardly.-

CARROLL R. ALDEN.

, spacedgrelation-fabout saidjbore, a'.

. fiilu'rliwfef risibile' respected? .reciprocable in `said cy1inders,.a plurality-fof inlet ports-opening respectively! to, said cylinders iri- .a 'common' trans- CERTIFICATE OF CORRECTION. Patent No. 2,195.612. March l2, 19M).

' CARROLL R. ALDEN.

It is hereby certified that error appears in the printed specificatie; of the above numbered patent requiring correction as follows: Page l, second column, line lh, for "Fig," read Eigs.; -page 2, Asecond column, line 5h, claim l, for the word "rotation" readrelation; page 5, first column, line MO, claim 5, before "cylinders" insert --i-pump-n; and that the said Letters Patent should vbe read with this correction therein .that the same mayV conform to the record of the case in the Patent Office.

Signed and sealed this lbrth day of May, A. D. 19140.

Henry-Van Arsdaie,

(Seal) Acting Commissioner of Patents.

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