US2465046A - High-pressure fluid pump - Google Patents

Description

March 22, 1949. w. 'r. TABB HIGH-PRESSURE FLUID PUMP Original Filed Feb. 4, 1942 '3 Sheets-Sheet l INVENTOR. Warner 7? 72M ATTORNEYS March 22, 1949. w. T. TABB 2,465,046

I HIGH-PRESSURE FLUID PUMP Original Filed Feb. 4, 1942 3'Sheets-Sheet 2 INVENI'bR. Warner T Tabb ATTORNEYS W. T. TABB HIGH-PRESSURE FLUID PUMP March 22, 1949.

Original Filed Feb. 4, 1942 mmvrm v hive/v0? I [153 MAZ'JORIYEYJ Patented Mar. 22, 1949 HIGH-PRESSURE FLUID PUMP Warner T. Tabb, Plainfleld, N. J., assignor, by mesne assignments, to Jack & Heintz Precision Industries, Inc., Cleveland, Ohio, a corporation of Delaware Original application February 4, 1942, Serial No.

Divided and this application March .6, 1945, Serial No. 581,288

This invention relates to a high pressure fluid pump more particularly adapted for use in fuel 17 Claims. (Cl. 103-41) Serial No. 429,464, filed February 4, 1942,- now Patent Number 2,372,694 granted April 3, 1945,

and of which this application is a division.

A general object of the invention is the provision of such pump structure which can readily and economically be manufactured in quantity production with interchangeable parts, easily assembled and efiectively and efiiciently used.

A more specific object of the invention is the I provision of such pump structure so constructed and arranged as to necessitate quite accurate fitting between mating parts of plunger structure and associated casing means structure, such as bushing structure, of only one relatively short portion of the length thereof, e. g. of only the port section of a plunger in a plunger bore, and with suitable provision of a low pressure fluid leakage chamber to avoid high pressure leakage.

An additional object is the provision in such pump structure of structural features permitting during assembly of parts of proper self-alignment of the port section of the plunger in the bore without detrimentally affecting substantially low pressure fluid-tight sealing.

A further object is the provision in such a structure of certain plunger structure provided with a plurality of fluid ports adapted selectively to be brought into communicative position with respect to low pressure fluid passage and selective interengaging means between plunger and casing means for permitting setting of the plunger in one of a number of difl'erent positions for delivcry of a definite quantity of fluid in each posi-' tion.

Other objects of theinvention will in part be obvious and will in part appear hereinafter.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

parts broken away of modified vention shown in Figure 1;

Figure 5 is an elevational view with parts in section and parts broken away of a pump plunger and associated collar or casing means and substantially low pressure fluid sealing means adapted to provide a leakage recess or chamber, constituting a modification of similar structure shown in Figures 1 and 4;

Figure 5A is a view in cross-section and with parts broken away of a portion of a pump plunger and an associated sealing means;

Figure 6 is an elevational view with parts in section and parts broken away of a pump plunger and associated collar and bushing with substantially low pressure fluid gasket sealing means provided between the latter two permitting relatively transverse movement therebetween on self-alignment of the plunger in the bore, constituting a modification of similar structure shown in Figures 1 and 4; and

Figure 7 is a view in cross-section of a portion of a modified form of pump including a two element pump plunger.

The present invention is adapted for incorporation in a pump of the general type disclosed in Purdy United States Patent No. 2,166,876 of July 18, 1939, which as more specifically explained therein constitutes an apparatus adapted form of the infor connection to a substantially low pressure supply system such as a supply tank of fuel oil and supply and venting conduit means. In apparatus of that type there may be provided a casing structure having a substantially axially arranged bore therein in which is mounted suitable metering valve structure through which low pressure fuel may communicate through passages to a plurality of pump plunger bores, one for each cylinder of the engine, arranged circumferentially of the-axial bore with, if desired,

' such pump plunger bores beingprovided by suit- Figure 1 is an elevational sectional view with Figure 3 is a sectional view taken on line 3- -3 of Figure Figure 4 is an elevational sectional view with able plunger bushings mounted in circumferenttially arranged holes in acasing, the casing and bushings comprising casing means. These pump plunger bores may further be suitably vented to low pressure fuel supply or a chamber connected thereto cooperating in the obtainment of substantially instantaneous cut-ofi of fuel under high and plunger operative means such as a suitable cam device. common to the plurality of pump plungers for successive operation thereof which latter structure may be located in a chamber in the casing structure with the chamber serving as a pump sump. The present invention is concerned with the casing means in which the pump plunger boreis formed and means for selectively positioning the pump plunger with a selected one of the ports of the pump plunger in communicative position with respect to the passage in the casing means.

Referring to the drawings like numerals refer to like parts throughout. A casing In formed if desired of metal may, in accordance with one embodiment of the present invention, be provided with a bore ll counterbored to provide a shoulder I2 preferably tapered, that is conforming to the surface of a truncated cone as shown, and further counterbored to provide an additional shoulder I; which may have the surface thereof lying in a plane substantially normal to the axis of the bore. Inward of the high pressure end the bore II is preferably internally threaded as shown at l4 and the outward end thereof is counterbored at l5 to receive plunger spring rigging, cam follower and associated structure. A relatively low pressure fluid passage l6 is formed therein communicating with the bore I I and adapted to be connected through suitable passages and metering valve structure to a relatively low pressure fluid supply and may serve both for supplying and venting relatively low pressure fluid to and from pump plunger bore. An additional venting passage I! may also if desired be provided.

Bushing means are fitted into the bore Ii and may comprise a, main bushing section having the high pressure end thereof fitted into the bore H, snugly if desired, inwardly of the shoulder l3 such as at I 9 for proper location of the bushing in the casing and set back in a midsection thereof such as at 20 to provide a shoulder 2| to cooperate with the bore shoulder I3 with the interpositioning therebetween of a high pressure gasket 22, formed of any suitable material such as, by way of example, dead soft copper. The bushing I8 is further set back to provide a shoulder 23 adapted to cooperate with the bore shoulder l2 and between the latter two shoulders is confined a low pressure gasket 24 formed of any suitable material such as, by way of example, babbitt metal. In the preferred form the gasket 24 is made substantially rectangular in section and deformed (to the shape shown) by the tapered seat i2 when the main bushing section I8 is forced into position with the high pressure gasket 22 predetermining such position.

The gasket 24 may be made of material softer than that from which the high pressure gasket 22 is formed, such as relatively soft deformable material, for example, soft metal of little elasticity, e. g. copper, lead, alloys thereof, etc., or from resilient material such as rubber, synthetic rubber, neoprene and the like.

In any case the arrangement is such that cooperating shoulders such as at l3 and 2| provide a substantially high pressure fluid-tight seal and determine the position of the bushing in the casing and a gasket such as that at 24 is deformed by shoulders such as at l2 and 22 to provide a substantially low pressure fluidtight seal without objectionably interfering with the desired locating or positioning of the bushing in the casing. By virtue of such structure it is not necessary to have the bushing carefully fitted into the bore ll throughout the length thereof and as shown it may be spaced from the bore wall between paired shoulders l8, 2! and I2, 22 and also outwardly of the latter thereby simplifying manufacturing. As a result the bushing is sealed into the casing at two different places simultaneously by the single act of sliding or forcing the bushing into the casing to a predetermined position (where it is to be held), and such locating is determined by only one pair of cooperating shoulders making for convenience in dimensioning and manufacturing to tolerances.

Further high pressure sealing may be attained by recessing the high pressure end of the bushing is such as at 25 and this recess may be so formed as provide a shoulder 26 substantially normal to the axis of the bushing and a tapered shoulder 21 substantially conforming to the surface of a truncated cone. A gasket 28 of suitable deformable material such as, by way of example, dead soft copper, which may be initially substantially rectangular in section. is compressed Within the recess 25 with its outside surface 29 engaging the wall of the bore H one flat surface engaging the shoulder 26 and a portion deformed to conform to the tapered seat 21. This deformation is attained by the positioning of a plug 20 in the high pressure end of the bore H such as by threaded engagement therein with the end of the plug engaging the other fiat face of the gasket 28. The plug ll thus retains bushing II in position in the bore II and is provided with a central opening which may have a portion thereof shaped to provide a seat for a check valve 3| which communicates with a bore in the plug adapted to receive a coupling member connecting thereto suitable conduit means leading to suitable nozzle structure in the wall of an engine cylinder (not shown).

The extent to which the gasket a may be compressed is limited and accordingly it may be used with the associated structure accurately to limit the insertion of the plug 20 into the bore ll due to the fact that after the gasket is deformed to the shape shown fiat surfaces of considerable area are engaged by shoulder 26 and the end of the plug 30.

With respect to the high pressure gasket 2!, as in the case of gasket 24, reliance may be placed on a small area of initial gasket seating such area of seating being increased thereafter during the final stages of forcing the plug 30 into its final position. Obviously the material for gasket 28 will be selected which will provide for the desired deformation, sealing and limiting of movement of the plug 20 into the end of the casing bore which of course will in part be dependent upon dimensions of associated structure relating to this feature. Fundamentally this feature is characterized by deformation of the gasket during an initial portion of the operation of forcing the plug 30 into bore ll while enabling plug 20 finally to find a positive seating surface of sufficient area so that termination of its movement into the bore is well defined and accords with a predetermined position. The final seating surface of area greater than the initial seating surface may here be provided by the relatively large area of final seating of the surfaces of the gasket 28 and the shoulder 28 and this in cooperation with resistance by the gasket material to deformation beyond a certain degree may determine the final position of the plug in the casing. Alternatively the final seating of the plug 30 may be ing avoids the necessity of carefuly aligning co-' operating surfaces of the bushing and plug and similarly carefully aligning cooperating surfaces of the bushing and easing. A slight misalignment of the plug surface with a transverse bushing surface such as 26 and likewise similar misalignment of the end surface of the plug with the end surface of the bushing such as suggested in Figure 4- would not give rise to any problems and of course there is no problem of leakage here involved.

It will thus be seen that with respect to the gasketing arrangement proposed above there is provided a structure wherein a bushing is sealed to a casing against low pressure at one place with- .out locatively determinning the position of the bushing with respect to the casing, is sealed against high pressure at-another place and its position with respect to the casing locatively determined thereat, and is sealed against high pressure but not located with respect to the casing at a third place, and in addition a plug holding the bushing assembled in the casing is first sealed and finally locatively positioned at that third place.

The bushing I8 is provided with a plunger bore 32 which, if desired, may have the high pressure end thereof counterbored as at 33 with a passage 34 communicating between the counterbored portion 33 and the passage 11. Such a feature is disclosed in the Tabb et al. United States Patent 2,247,421 'of July 1, 1941-, wherein it is explained that fluid under pressure in front of the pump plunger is vented through such passages to reduce the pressure of the fluid in the conduit to the engine cylinder'sufiicientiy to permit a spring biased valve in nozzle structure to close thereby cutting off fluid discharge from the nozzle. Such a feature, however, is not essential to the structure of the present invention.

In the counterbored portion l of the bore of the casing ill is reciprocatively mounted a skirted or tubular plunger follower 35 having a base portion 36 recessed at 31 to receive a follower roller 38 mounted on a pin 39 disposed in a hole traversing the base 36 with the'roller 38 engaging a suitable cam surface 40 which may be located in a pump sump or cam chamber. The base 36 of the follower 35 may suitably be pierced longitudinally to avoid the formation of a vacuum or compression chamber in the counterbored pormounted into the casing to assure proper alignment of all such parts, and proper cooperative functioning thereof even though in production there has been as independent sizingoi' the two pairsof ,rnating cylindrical parts, the plun er and main bushing section, and the plunger and; collar. The. sci-formed leakage tion I5 during reciprocative operation of the follower. A land or projecting portion 4| is provided on the base 36.

A pump plunger 42 of any suitable design may be suitably fitted in the plunger bore 32 of the bushing l8 and preferably comprises a high pressure end 43, a port section 44, a sealing section 45, and an outward operable end 46 for engagement with the projecting portion 4| of the follower 35 for inward movement thereby.

Circumambient of the plunger 42 is arranged an auxiliary bushing section 41 which may be a collar radially spaced therefrom and having a flange 48 in substantially low pressure fluid-tight sliding engagement with the sealing section 45 of the plunger 42 to provide a leakage recess 49. The main bushing section 1 is provided with a shoulder 50 which is engaged by one end of the collar 41 preferably with a transverse sliding fit .to assure the formation of a leakage chamber constituted by recess 49 and freely permitting self-alignment of the plunger with respect to the bushing and with respect to the collar when being chamber may be vented in any suitable manner such as by a passage 5| communicating with a passage 52 in communication with passage l6. The passage 52 may be formed in any suitable manner after machining. surfacing and hardening .of the main bushing section 18 such as by grinding a transverse slot therein which does not break through the plunger bore surface, and the bushing may be ported at 53, aftersuitably finally sizing the bore 32 such as by fitting or lapping a plunger therein. This may be accomplished by grinding or otherwise cutting a transverse slot more deeply into the bushing until a port 53 of desired dimension is broken through into the bore 32, such so-formed port having sharp effective or working edges from which burrs may be stoned off if necessary.

The collar 41 may be held in engagement with the main bushing section l8 by any suitable means such as by members secured to the main bushing section or supported from the casing but preferably is held in position by means biasing the plunger which may be a helical spring 54, one end of which abuts or seats against flange 55 on a cup-shaped member 56 having a flange 51 engaging against a shoulder 58 on the collar 41. Other abutment means for the other end of the spring 54'are mounted on the plunger 42. Such means may comprise a skirted collar 59 having an inwardly facing tapered surface '60, such as a substantially spherical surface as adapted to cooperate with a tapered surface 6! within an abutment cup 62 having a flange 63 against which the other end of a spring 54 seats. A groove 64 in the operable end 46 of the plunger cooperates with the skirted collar 59 to confine between the shoulder 65 within the collar 59 and a shoulder 66 formed by groove 64 any suitable element such as a ball 61 or a plurality thereof, or a relatively soft split ring, helical spring torus or the like. Such structure permits ready removal from the plunger of the. parts includingthe spring which is attained by compressing the spring 54 to permit the skirted collar 59 to be moved inwardly on the plunger sufliciently to free the securing means such as the balls 61.

Means are preferably provided on the plunger to cooperate with the'flange 48 of the collar 41 so that a subassembly may be provided. Such means may constitute a pin 68 located in the recess or chamber 49 and loosely held in a transverse hole 69 in the plunger 42 by the collar 41. As a consequence the plunger 42, pin 68, collar 41, member 56, spring 54, skirted collar 59, cup member 62 and balls 61 may be assembled into a subassembly the parts of which securely remain in relative positions prior to assembly thereof with the casing or main bushing section and cam follower thereby facilitating and simplifying assembly of the parts of the pump mechanism. The pin 68 also may serve as a guide pin for interengagement with casing means as hereinafter explained and for a purpose indicated.

The plunger 42 preferably is provided with a plurality of sets of supply and venting ports selectively to be used for delivery of different quantities of fluid. The set of supply ports may be three in number arranged circumferentially shown,

of the plunger about 120 apart as indicated in Figures 2 and 3 and may comprise ports II, II and 12 each having a working or effective controlling edge 13 located at a certain point along the plunger. A set of venting ports are paired with the supply ports and may comprise the three similarly arranged as indicated at I4, 15 and 14 each of which has an effective or working edge I1 also arranged at a certain point. The distance between the edges 13 and 11 of any pair of ports angularly positioned for cooperation with effective or working edges of the port or ports of a passage or passagesleading into the plunger bore determines the capacity of the pump cylinder for that particular plunger position. This distance minus a corresponding distance between the effective or working edges of the casing means port or ports is the length of the eifective stroke of the plunger. If desired, the effective working edges of a certain pair of supply and venting plunger ports may be located at a distance apart differing from that for other pairs of ports, which as shown only by way of example differs for any one pair of ports. With one port provided by passage 53 in the bushing serving both as a bushing supply port and bushing venting port for each plunger bore, as shown by way of example in the structures depicted in the drawings. this distance between effective edges of bushing ports is the distance between a leading effective edge I and a trailing effective edge 532 which is the same for all pump cylinders and for all positions of any one pump plunger. The effective stroke of any one pump plunger of the depicted structures for any one pair of supply and venting ports is the distance between edges 13 and 11 thereof minus the distance between bushing port edges SN and 531. As desired the supply ports 10, 1i and I2 and venting ports l4, l and I6 may be formed with their edges respectively arranged as shown or may be formed with all of the effective trailing edges |313 of the supply ports arranged in the same transverse plane and eflective leading edges '||--T| arranged in different transverse planes. A further alternative is the arrangement of all leading edges '||'i1 in the same transverse plane and the trailing edges '|3'I3 in different transverse planes.

The different pump capacities provided by the different selective plunger positionings may be attained by providing a plurality of passages similar to 53 in a single bushing with the effective working edges 53l and 532 of theport of each spaced differing distances apart and associating therewith a plunger having only one pair of supply and venting ports which selectively may be brought into working position with respect to any one of such bushing ports by selective angular positioning of the plunger.

Such novel port features obviously may be incorporated in plungers of the axial passage type wherein a longitudinal passage 18 extends substantially axially from the high pressure end 43 through the port section 44 of the plunger, and this may be brought into communication with the ports ill, ii, 12, 14, i5 and 16 in any suitable manner such as by drilling holes 19-19 such passage I8 and a hole 19 cooperatively serving as a fluid way between high pressure end 43 and a port. However, it will be understood that other methods of providing ways for passage of fluid between such ports and high pressure end 43 of the plunger may be utilized in practicing the invention such as, for example, by forming grooves in the cylindrical surface of the plunger to extend cylindrical plunger is made of this material and first machinedto a dimension considerably oversized and a bushing formed of similar material is provided with a bore considerably undersized. Thereafter these elements may be heat treated to give greater hardness and a molecular structure of the cylindrical surfaces more suitable for hardening by nitriding. After heat treating the cylindrical surfaces are preferably ground to remove the extreme outer surface to permit more effective nltriding and incidentally for closer sizing. This grinding, however, is to dimensions which are still oversized for the plunger and undersized for the bushing. The elements are then subjected to a nitriding treatment wherein the ammonia gas causes hardening. A te" nitriding a final grinding of the cylindrical surfaces is performed to dimentions not quite the final size, there being provided an allowance of a few tenthousandths of an inch for lapping to give a perfect fit of the mating parts. After fitting the mating parts such as by lapping, the ports are ground into the cylindrical surfaces as a final step of operations on such surfaces, so that uninterrupted surfaces are bad for sizing or fitting the mating parts together whereby sharp, definitive, effective or working edges of ports are assured. This avoids dulling of such edges by machining, grinding and lapping since in lapping, lapping compounds tend to collect at edges and to form a slight tapering of cylindrical surfaces at such points, and in machining or grinding surfaces the operations tend to remove excessive amounts of material at the edges of interruptions of the surfaces. For example, pressure of a grinding wheel against the work is slightly relieved at the edges of interruptions, so that there is no tendency excessively to remove material thereat.

In so forming such plungers characterized by the provision of fluid passages from the high pressure ends of the ports such as the axial passage 18 and the holes IS-19 these may be formed'such as by drilling prior to the hardening, grinding, lapping and final porting. This is permissible since the holes IO-I9 are of less dimension than the width between the opposed edges of any one port. Accordingly, even though in grinding and lapping excessive material is removed adjacent the edges of the holes |918 the dulled or imperfect surfaces adjacent thereto will be ground off in the formation of the ports. Further, the axial passage 18 and the holes 18-" may be provided at any time during the process of formation even subsequent to the porting. For example, a portion of the area of the high pressure end of the plunger may be protected from hardening such as by plating or painting andthen subsequent to the hardening, the axial passage Il may be drilled and the holes IO-1O may be drilled either prior to or subsequent to the final sizing or lapping and, of course. prior or subsequent to the porting. Further, if it be desired to drill the passage 18 prior to hardening, protection for the surface thereof may be provided by plugging with clay or otherwise, or the surface of the passage 18 may be protected by painting with certain paint which prohibits infiltration of ammonia gas. As an alternative, when the passage I8 is formed prior to hardening. the surface thereof may be left unprotected since in drilling the holes IS-18 no difliculty is found in piercing through the hardened surface or crust of the axial passage 18 since this crust in the case of nitriding is quite thin. It is to be understood that hardening treatments other than nitriding may be used. In such cases, particularly where the material from which the plungers and bushings are formed is not such as to make for the obtainment of advantages attributable to heat treating, such heating before hardening and grinding will be omitted. The presently preferred procedure for making the plungers comprises drilling the axial passage 18 prior to hardening and then after hardening, further grinding, lapping, and finally porting, the holes 19-49 are drilled through from the ports into axial passage I8; but in any case, regardless of what variations of procedure are adopted, the formation of the ports in the cylindrical surfaces of both the plungers and the bushings is always done subsequent to the treatment and the final mechanical working of those surfaces (such as lapping and fitting) to assure the obtainment of sharp accurately operative eifective working port edges. Obviously the formation of the passages and 52 and the formation, such as by grinding, of the port passage 53 in the main bushing section i 8 may lie-accomplished in a variety of ways as to time and method of formation, similar to those pointed out above in connection with the formation of an axial passage 18 and passages 1919 in the plunger. Thus the two basic pump elements, the plunger or piston and the bushing constituting the cylinder or barrel, are finished and ported by a similar procedure of the present invention.

The outward end of the main bushing section l8 may be provided with a flange 80 circumambient of the plunger 42, preferably within the chamber 49 and this flange may, be. provided with three pairsof diametrically opposed longitudinally extending ways or slots 8l8'l with each pair arranged about 120 from the succesive pair similar to the arrangement of the pairs of ports in the plunger. A pair of opposed slots 8l--8l are-adapted to receive the opposite ends of the pin 68 as shown in Figs. 1 and 4 for positioning of a pair of supply and venting ports of the plunger in selected communicative relation to the port end of passage 53. Accordingly, the plunger' 42, when being mounted with the other parts of the sub-assembly relative to the bushing section I8 and casing l0, may be placed 'in a selected desired. operative position in the plunger bore whereby the guide pin 68 serves not only as means to hold the parts of the sub-assembly together but also as an indexing and guiding means. After placement of the sub-assembly in the bushing section ll! of easing Hi the follower 35 is then inserted in the counterbored portion I5 of the casing bore.

It will be understood that any suitable interengaging'mearis between the plunger and casing means may be used for this purpose of indexing and guiding. For example, only one pair of diametrically opposed slots 8l--8l need be formed in the flange 80, and the plungermay be providedwith three transverse holes 5969, asindicated in Figure 4, so arranged as to provide for different selective placement of pin 68.

Although the structure described above for the provision of the leakage chamber 49 is preferred, obviously it is not essential to form the collar member 41 separately from the bushing or casing means with the provision therebetween of a substantially low pressure fluid-tight transverse sliding fit. The desired provision for self-alignment of the plunger 42 may be obtained by resilient means. In Figure 5 such a structure is illustrated wherein the collar member may be a flange portion 82 formed integral with the main bushing section or casing means. A groove 83 may be formed in the sealing portion 45 of the plunger 42 and a resilient ring 84 ofsuitable material such as neoprene may be seated therein with its outer surface slidably engaging the inner wall of the portion 82 in a substantially low pressure fluid-tight sealing manner. As shown in Figure 5A, a ring of resilient material 84a may be fixed relative to the portion 82 with the provision of a substantially low pressure fluid-tight sliding flt with the sealing portion 45 of the plunger 42, thus being used as a flange in lieu of that at 48 illustrated as being made integral with the collar 41.

Further, it will be understood from-Figure 6 that the surfaces at the cooperating ends of the bushing section l8 and collar 41 need not of necessity be lap-fitted if a gasket 85 of any suitable material permitting relative transverse movement of the collar and bushing section is interposed. This gasket may, if desired, be formed of relatively resilient material such as neoprene. It will be further understood that the self-alignment of plunger structure relative to casing means structure wherein such independent fittings of the plunger structure at the port section of the casing means structure bore and at the outward end of the casing means structure constituting a closure for the leakage chamber may be provided by a structure wherein the' bushing section l8 and collar 41 are rigidly made integral with each other while permitting the use of a rigid closure flange such as 48, if the plunger structure comprises sectionswhich may be movable relative to each other transversely. As illustrated in Figure 7, a two part plunger structure 42a, 42b might be used within the scope of the invention wherein the plunger part 420. is aligned in the port section of the bore 32a and is abutted against the other section 42b which is slidably fitted in the closure flange 48a and with their adjacent ends in abutting relation, so that the plunger ported section 42a may be forced inwardly by the other section and return stroke of the former obtained by suitable biasing means such as a spring 52a at the high pressure end of the plunger structure. The pin 68 may be received in groove 92 in the end of the section 4211 to facilitate adjustment and indexing of the plunger section 42a.

If desired, the provision for centering and/or balancing action of the spring 54 may be omitted from the abutment means mounted on the plunger and additionally the means for biasing the collar 41 with a transverse sliding fit to the bushing I8 may be modified all, as illustrated in Figure 4. By way of example a plate 86 having a spring seating flange 81 may be mounted on the end 46 of the plunger 42 by placement of suitable means such as a split ring 88 in the groove 84. The opposite end of the spring 54 may be seated directed against casing structure rather than means mounted on the collar 41 such as by seating it against a shoulder 89 on the casing l0 and the collar 41 may be held in engagement with the casing means or bushing l8 by an auxaeeaoee iliary spring I. seated at one end on plate ID and at the other end-against'the collar 41 or the flange 48 thereof. In such a case the subassembly would include the helical spring 80 and the plunger biasing spring 54 would be mounted as a separate element at the time of assembly of the sub-assembly in the bushing or casing means. Obviously the helical spring 80 supplements the biasing of the plunger by the spring I4. Other and further modifications of such structure and associated parts within the scope of the invention will readily occur to those skilled in the art.

The cooperating tapered surfaces 80 and ii of the abutment means mounted on the plunger for the spring rigging are preferably shaped as described but not necessarily so. The surface Ii could be somewhat spherical having a greater radius of curvature than the spherical surface II or the latter might be made conical similar to the illustrated shape of the surface BI and the latter could be convexed to cooperate therewith. Resulting line contact or at least small area of contact are desired for attainment of centering and/or balancing action of the spring 64 to avoid cocking of the plunger 42 which has been provided with only a relatively short accurate sliding fit in the plunger bore.

As described above, the high pressure gasket I 28 may predetermine the position of the plug 30 in the high pressure end of the casing bore ll. Such predetermination of position may additionally be attained, as indicated, by causing the end of the plug 30 to engage the high pressure end of the bushing it such as at 9| as shown in Figure 4 after the gasket 28 has been suitably deformed.

and depressed in the recess 25. The'provision of the gasketing 28 makes possible the use of such structure without necessitating accurate lining up of cooperating surfaces of plug 30 and bushing section ll at 9|.

It will be understood that the following terms as used in the specification and claims are intended to have the followin meanings. Casing means" may include plunger bushing means, if used, and a surrounding casing or may refer to a casing alone when the plunger bore is formed directly therein. "Bushing means may include a main bushing seated in the casing and an auxiliary bushing means section which may be a collar having a substantially low pressure fluidtight seal or transverse sliding fit with themain bushing. The fiange" on the collar engaging the plunger may be made of any suitable material such as the metal from which the collar may be made and integral with or separate therefrom, or of resilient material such as neoprene whereby a transverse sliding fit between a leakage chamber collar and easing means need not be provided. The term outwardly refers to direction away from the pump casing, that is toward the cam follower or operatively engaged end of the pump plunger; and inwardly refers to the reverse direction, that is into the pump casing or bushing therein since the pump plunger is forced inward or into the plunger bore on the working stroke. Relatively low pressure fluid" refers to fluid fed to the pump such as by a suitable system i or permit only very little or negligible leakage at the indicated pressures such as some minor or unimportant seepage of fluid film transfer.

In operation, with the parts assembled and positioned as shown in Figure 1 and a low pressure fluid or fuel supply connected with passage it such as through suitable meterin valve structure, the cam surface of cam plate 40 upon rota- 'tion of the latter will permit the pump plunger to be forced by the spring biasing structure outwardly out of bore 32 until the supply port 10 is opened to the passages l3, l2 and i8 permitting low pressure fuel to enter through the supply port, opening I! and plunger passage 18 into the bore ahead of the high pressure end 43 of the plunger. Upon further rotation of the cam plate 40 of the follower II is forced inwardly against the action of the spring I4 forcing the plunger into the bore 32 until the effective trailing edge 13 of the port I0 passes the bushing port edge Ill and thereafter to compress the so-supplied fuel in the plunger bore. This fuel under pressure will unseat the valve ii in the plug 30 and permit sufficient pressure to be built up in the conduit leading to the nozzle whereby to unseat a valve therein so that the fuel will be sprayed into the engine cylinder. On further movement of the plunger 42 the efiective or leading edge 11 of the venting port will pass the bushing port edge "2 quickly to vent fuel under high pressure through plunger passage-ll, opening 19 and port 14 to the fuel supply to obtain substantially instantaneous cut-off of fuel supplied to the engine cylinder and accurate delivery of a predetermined quantity thereof. Upon further rotation of the cam 4| the follower 35 will be permitted to recede from the counterbored portion I! as the biasin spring 54 forces the plunger 42 outwardly again bringing the supply port ll into communication with the passage 53, and thereafter the cycle is repeated.

By virtue of the structure of the invention described substantially no leakage of fuel from the high pressure system between the engine cylinder and pump will occur past the plunger and bushing into the pump sump (in which the cam 40 and other operating parts are located) and lubricating oil therein. Infiltration of lubricating oil into the low pressure system is likewise avoided even if a fair amount of pressure of lubricating oil exists in the pump sump. Avoidance of such leakage is accomplished by means of the auxiliary bushing section or collar 41 and the leakage chamber 49 provided thereby and vented to the low pressure supply by passage ll, so that any leakage past the plunger into this chamber is automatically returned to the low pressure system. The fit of the collar 4'! through its flange 48 or similar structure with the sealing section of the plunger is independent of the fit of the port section 44 of the plunger in the bushing bore 32 so that the latter need be accurate within a limited tolerance only adjacent to the ports and to provide a reasonable line-up of parts. This fit between collar flange 40 and the plunger is of necessity only of the low pressure type and, therefore, is a comparatively easy fit to obtain and maintain, and makes readily practicable interchangeable or selective manufacture of parts and assemblies. In fact, the length of the surface of sliding fit between the collar flange 48 and the sealing portion 45 of the plunger 42 is preferably made comparatively short, so that the line-up of the end surfaces of the collar and main bushing section It is easily 13 and readily obtainable. Further, such structure readily permits self-alignment ofthe plunger in the bore independent of the alignment of the plunger and collar or flange 48 thereof and provides for independent fitting at these two surface matings thereby greatly simplifying manufacture and increasing likelihood of proper fittings. This avoids the necessity for accurately fitting a pair of mating cylindrical parts over a great length, or in two separate sections simultaneously.

Since in the present structure the accurate sliding-fit of the plunger in the bushing bore 32 may be relatively short. that is throughout the port section 44, the problem of obtaining satisfactory fit of these parts is greatly simplified. This makes possible manufacture of parts to gauge-inspection as contrasted to individually fitting of parts by lapping on assembly. As a result a so-called selective assembly system in which the cooperating parts are each made to a certain dimension with a. reasonable tolerance and the parts are paired, so that the fit of a y two paired parts may be much closer than the tolerances permitted is possible which may make unnecessary accurate fitting at the time of assembly. Such a system will include mating of parts which may be easily accomplished in commercial production. By this is meant the manufacture of the parts to predetermined gauge dimension within a reasonable tolerance range. As a result the dimension of some of the parts will be that dimension plus, others possibly practically to that dimension, and still others that dimension minus. Such parts will accordingly be separately grouped or classified according to such dimensions as will the parts with which they are to fit, thus constituting the referred to mating. Such so-classified parts will thus be interchangeable with any other part selected from the same grouping which will permit utilization of standard methods of interchangeable manufacture and a resultant elimination of manufacturing difficult es usually acceptably recog-- nized in the production of pumps of this type.

It will be noted that the construction is featured by a plurality of mating parts wherein each mating is independent of others and of a single dimension as contrasted with plural or two dimension mating such as in pump construction where a plunger must be accurately fitted to the bore at both the port section and the outward end of the bore. There one dimension fitting controls the porting and the other dimension fitting controls the leakage between the plunger and bushing at the outward end of the bore. It has been found in manufacture of such latter constructions that after carefully fitting the plunger to the bore at the port section, there often is not a proper mating of the plunger and the parts are of such construction as to per-' mit classifying all of a multiplicity of any one part in a single group; both types of systems being practicable in commercial production of pump structure assemblies of the present invention with assurance of efiicient operation thereof.

In view of the fact that only relatively short mating surfaces of the pump plunger and bushing bore ar essential to eflicient operation of the mechanism of the present invention and are desired for indicated reasons, provision has been made to assure at all times in assembly and operation of a proper alignment of the parts with substantial elimination of. possible transverse pressure against the relatively long section of the plunger between the port section thereof and its operative end 46. Accordingly, th outward end of the plunger rides freely on a smooth surface of the follower 35 and provision is preferably made for balancing biasing action of spring 54 thereby avoiding possible cocking of theplunger.

Accordingly, provision is made for limited transverse movement of the plunger by reason of th construction of auxiliary bushing section or collar 41 or the sealing means interposed therebetween and in addition the provision of the swiveling structure in the abutment means mountedon the plunger and against which an end of the biasing spring seats. The above described cooperating tapering surfaces in that abutment means permits a suitable swing of the spring seating member and thus tends to equalize spring pressure at all points circumambient of the plunger.

It will thus be seen that the objects set forth above and those herein indicated are efliciently attained, and since certain changes in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description orshown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense;

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a high pressure fluid pump the combination comprising, a casing having a bore therein, a bushing seated in the bore terminating in an outward end and having a plunger bore therein,

bushing at the outward end of the bore such a selective assembly system wherein a multiplicity of any one part are classified into two, or'

and relatively low pressure fluid passage means communicating with the plunger bore, a plunger slidably fitted into said bushing and having a head end, said plunger having port and passage means to provide for passage of fluid between the bushing fiuid passage means and the head end of the plunger, oneof said passage means consisting of a plurality of circum'ferentially arranged passages, said'plun'zer being adapted to be operated in a plurality of predetermined angular positions with each position thereof bringing about cooperative communication between the bushing fluid passage means and the plunger port Thus the a guide pin on said plunger selectively disposed.

in one of the slots to assure sliding action of said plunger in a selected one of the predetermined angular positions.

2. In a high pressure fluid pump the combination comprising, casing means having a plunger bore and a relatively low pressure fluid passage communicating therewith, a pump plunger slidably mounted in the bore having a head end and a set of ports circumferentially arranged around the plunger for selective communication with the casing means passage, said plunger having passage means to provide for passage of a deflnite quantity of fluid between each port and the head end of said plunger, and selective interengaging means between said plunger and said casing means to assure cooperative operation with a selected one of the ports in communicative position with respect to the casing means passage.

3. In a high pressure fluid pump the combination comprising, casing means having a plunger bore and a relatively low' pressure fluid passage communicating therewith; a pump plunger slidably mounted in the bore having a head end,

a longitudinal way extending from the head end thereof and a set of ports circumferentially arranged around the plunger for selective communication between the casing means passage and the plunger way with each port being adapted to provide for a definite quantity of fluid; and selective interengaging means between said plunger and said casing means to assure cooperative operation with a selected one of the ports in communicative position with respect to the casing means passage.

4. In a high pressure fluid pump the combination comprising, casing means having a plunger bore and a relatively low pressure fluid passage communicating therewith;- a pump plunger slidably mounted in the bore having a head end, a longitudinal way extending from the head end thereof and a set of differing ports circumferentially arranged around the plunger for selective communication between the casing means passage and the plunger way with each port being adapted to provide for a definite quantity of fluid difierent from that obtainable with another of the ports; and selective interengagingmeans between said plunger and said casing means to assure cooperative operation with a selected one of the ports in communicative position with respect to the casing means passage.

5. In a high pressure fluid pump the combination comprising, casing means having a plunger bor and a relatively low pressure 'fluid passage communicating therewith through a port having an eiiective edge; a pump plunger slidably mounted in the bore having a head end, a longitudinal way extending from the head end thereof and a set of ports circumferentially arranged around the plunger communicating with the longitudinal way with each port having an eflective edge so located along th plunger as to cooperate with the efifective edge of the casing means port at a point along the path of movement.

of said plunger difiering from such point for another of the ports; and selective interengaging means between said plunger and said casing means to assure cooperative operation with a selected one of the ports in communicative position with respect to the casing means passage.

6. In a high pressure fluid pump the combination comprising, casing means having a plunger bore and a relatively low pressure fluid passage communicating therewith through a port having an effective edge; a pump plunger slidably mounted in the bore having a head end, a longihaving an eifective edge so located along the plunger as to cooperate with the eifective edge of the casing means port at a point along the path of movement of said plunger diflering from such point for another of the ports; said casing means having a set of longitudinally extending slots circumferentially arranged with respect to the bore similarly to the circumferential arrangement of the ports in the plunger; and a guide pin on said plunger selectively disposed in one of the slots to assure cooperative operation of said casing means and plunger with a selected one of the ports in communicative position with respect to the casing means passage.

7. In a high pressure fluid pump the combination comprising, casing means having a plunger bore communicating with relatively low pressure fluid supply and venting means through porting having eflective leading and trailing edges; a pump .plunger slidably mounted in the bore having a head end, a longitudinal way extending from the head end into the body thereof, a set of supplyv .ports circumferentially arranged around the plunger communicating with the longitudinal way with each having an eifective trailing edge, and a set of venting ports similarly arranged circumferentially with each paired with one of the supply ports and having an effective leading edge. at least one of the efiective edges of each pair of ports being so located along the plunger as to cooperate with one of the effective edges of the casing means porting at a point along the path of movement of said plunger differing from such point for the like port of another of the pairs; and selective interengaging means between said plunger and said casing means to assure cooperative operation with a selected pair of supply and venting ports in communicative position with respect to fluid supply and venting means.

8. In a high pressure fluid pump the combination comprising, casing means having a plunger bore and a relatively low pressure fluid passage communicating therewith through porting having effective leading and trailing edges; a pump plunger slidably mounted in the bore having a head end, a longitudinal way extending from the head end thereof, a set of supply ports circumferentialiy arranged around the plunger communicating with the longitudinal way with each port having a trailingedge so located along the plunger as to cooperate with the effective leading edge of the casing means porting at a point along the path of movement of said plunger diifereng from such point for another of such ports, and a set of venting ports similarly arranged circumferentially communicating with the longitudinal way with each paired with one of the supply ports and having a' leading edge so located along the plunger as to cooperate with the effective trailing edge of the casing means porting at a point along the path of movement of said plunger differing from such .point for another of the venting. ports; and selective interengaging means between said plunger and said casing means to assure cooperative operation with a selected pair of supply and venting ports in communicative position with respect to the casing means passage.

9. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end,

a working port section having a set port circumerentially arranged being adapted for selective communication with of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

10. In a pump having a bore and fluid passage means connecting therewith,--a cylindrical pump plunger in said boreand comprising a head end, a'working' port section having. a longitudinal way extending from said head end and a set of ports circumferentially arranged around it and communicating with the way, each port being adapted for selective communicafion with said fluid passages to provide for supply of a definite quantity of'fiuid to in front of the head end, longitudinally extending slots in said bore and means on a section of said plunger outward of said port section for selective cooperative engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

11. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end, a working port section having a longitudinal way extending from said head end and a set of difiering ports circumferentially arranged around it and communicating with the way, each port being adapted for selective communication with said fluid passages to provide for supply of a definite quantity of fluid to in front of the head end different from that obtainable with another of the ports, longitudinally extending slots in said bore and means on a section of said plunger outward of said port section for selective coop-- erative engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

12. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end, a working port section having a longitudinal passage extending from said head end and a set of ports circumferentially arranged around the plunger communicating with said longitudinal passage with each port having an effective edge located a distance from the plunger head end differing from that for another of the ports; longitudinally'extending slots in said bore and means on a. section of said plunger outward of said port section for selective cooperative engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

13. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end, a working port section having alongitudinal passage extending from said head end and a set of ports circumferentially arranged around the plunger communicating with said longitudinal passage with each port having an effective edge located a distance from the plunger head end differing from thatv for another of the ports, longitudinally extending slots in said bore and a guide pin on a section of said plunger outward of said port section for selective engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

14. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end; a working port section having a longitudinal passage extending from said head end, a set of supply ports circumferentially arranged around the plunger communicating with said longitudinal passage with each having an effective trailing edge, and a set of venting ports similarly arranged circulnierentially with each paired with one of the supply ports and having an eiiective leading edge, at least one of the effective edges of each pair of ports being located a distance irom the plunger head end differing from that for the like port of another of the pairs; longitudinally extending slots in said bore and means on a section of said plunger outward of said port section for selective cooperative engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

15. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a head end; a working port section having a longitudinal passage extending from said head end, a set of supply ports circumferentially arranged around the plunger communicating with said longitudinal passage with each port having a trailing edge located a distance from the plunger head end differing from that for another of said ports and a set of venting ports similarly arranged circumferentially communicating witth the longitudinal passage with each paired with one of the supply ports and having a leading edge located a distance from the head end differing from that for another of said venting ports; longitudinally extending slots in said bore and means on a section of said plunger outward'of said port section for selective cooperative engagement with said slots to assure operation of said plunger with a selected one of said ports in communicative position with respect to said pump passage.

16. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a working section and an operating abutting section, said working section having a head end and a longitudinal way extending from said head end and a set of difiering ports circumferentially arranged around it and communicating with said way, each port being adapted for selective communication with said pump passage to provide for supply of a definite quantity of fluid to in front of the head end different from that obtainable with another of the ports, longitudinally extending slots in said bore and means on said working section outward of said ports for selective cooperative engagement with said slots to assure operation of said working section with a selected one of its ports in communicative position with respect to said pump passage.

17. In a pump having a bore and fluid passage means connecting therewith, a cylindrical pump plunger in said bore and comprising a working section and an operating abutting section, said working section having a head end and a longitudinal way extending from said head end and a set of differing ports circ'umferentially arranged around it and communicating with said way, each port being adapted for selective communication with said pump passage to provide for supply of 3. REFERENCES Cum definite quantity of fluid.to in front of the head The following references are of record in the end diflerent from that obtainable with another file Of t s Pate t:

of the ports. said working section at its other end UNITED STAT-Es P m being provided with a set of grooves angularly A disposed in correspondence to the circumferential Number Name I Date arrangement of said sets of ports, longitudinally Tabb P 1945 extending slots in said bore and a guide pin 10- FOREIGN PATEL-v13 cated in one of said grooves for selective coop- 10 Number country mtg erative engagement with said slots to assure op- 734,659 France n 1982 eration of said working section with a selected one of its ports in communicative position with respect to said pump passage.

. WARNER T. TABB. 15

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