US2310370A - Pump structure - Google Patents

Description

Feb- 9, 1943 J. F. HoFFr-:R 2,310,370 v PUMP S TRUCTURE James E Hoffefrl Feb. 9, 1943. J. F. Hor-FER PUMP STRUCTURE Original Filed May '7, 1938 'Jmea' f? Hoffe"Y B @by M y' W ATTORNEY.

2 Sheets-Sheet 2 Patented Feb. 9,

Cell- Corporation, Detroit, Mich., a

tion of Michigan Original application May 7,

206,509. lDivided, 8.11

1938, Serial` No.

d this application July 8, 1940, Serial N0. 344,343 v tcl; s-'37)' 4 end of the housing'li, and is formed with a cen# 21 Claims.

. The present invention relates to improvements in pump structures and has particular reference t0 a pump structure adapted for supplying f uel in metered charges and under pressure to' an internal combustion engine.

One of the objects of the invention is to provide a new and improved pump structure comprising a relatively high pressure delivery pump, r I

and a primary pump for supplying iiuidunder a relatively low pressure to the inlet of the first mentioned pump and also for returning uid leakage from the first mentioned pump Awith the normal uid supply to' the inlet. f

Another object is to provide, a novel pump structure of the foregoing character inwhich the two pumpsare connected in a unitary structure and are driven in timed. relation and in ,which the primary pump has an auxiliary pump vfor in-v troducing fluid leakage from the interior of the delivery pump into the primary pump.

In the accompanying drawings, Figure .1, is a side elevational view partially in longitudinal section of a pump structure embodying the features of my invention. y

Fig. 2 is a fragmentary transverse sectional view taken along line 2-2 of Fig. 1.

tral bore 6 and with a plurality of parallel pump cylinders 1 arranged in annularly spaced'rela tin about .the bore. A mummy of pumppistons 8 are reciprocably disposed Ain the cylinders 1 and are urged outwardly by compression springs 9.v Mounted in the other endof the housing4 is a driving mechanism fo ee'cting reciprocation of the pistons 8 in unionnly'tlmedjsequence. This mechanism comprises a pluralityofactuating plungers II reciprocably guldedinthe housing 4, and disposed in axial alignment and end abutting engagement respectively with the pistons 8. yA rotary swash plate I2 coats with the Fig. 3 is a fragmentary transverse sectional view taken along line 3-3 of Fig. 1.

I Fig. 4 is an enlarged fragmentary sectional view of the auxiliary leakage pump. v

The present application is a division of my copending application Serial No. 206,509, filed May 7, 1938 (Patent No. 2,265,232).

Referring more particularly to the drawings, the pump structure illustrating the invention comprises generally a delivery pump I for discharging uid under a relatively high pressure, and a primary pump 2 for supplying or transferring fluid under a relatively low pressure to the inlet of the delivery pump. rI he primary pump 2 serves also to return uid leaking from the `de- ,livery pump to the inlet ofthe latter, and for this purpose 4preferably includes an auxiliary pump 3 for introducing the leakage iluid into the primary pump for mixture and delivery with the normal uid supply.

The highpressure delivery pump I may be of any desired form or type, and is herein disclosed for purposes of illustration as an adjustable metering and distributing fuel pumpl like that` disclosed vin United States Letters Patent to Carroll R.. Alden No. 2,156,933, issued May 2, 1939.

Briefly described, the'Y delivery pump I comprises a housing 4 adapted to be mounted on a suitable support. A cylinder body 5 is mounted in one plungers II, and is operable by a central drive shaft I3 in axial alignment with the bore 6. The pressure ends ofthe pump spectively past check valves delivery lines I5, and have individual inlet ports I6 opening in a common transverse plane to the bore 6. A groove Il is formed in the periphery of the bore 6, and is open to an inlet passage I8 connected to a low pressure uid supply line I9. Mounted in the bore 6 is a rotary valve member '20 having a relief area 2I adapted to eiiect communication between the ports I6 and the lgroove I1 and having an arrow land area 22 movable success'ively across the ports to 'close each'port during a predetermined portionof the working stroke of the associated piston 8. The valve memberv20 is operatively connected to the shaft I3 for rotation thereby in timed'relation to the reciprovcation of thepistons 8.

In operation,` predetermined quantities of a, relatively high pressure and in timed sequence to the delivery lines I5. lAny fluid leaking .from the closed ends o f the cylinders 1 along the pistons 8 or from' the groove I1 inwardly along the valve member-20 will pass into the interior of the housing 4 between the cylinder body 5 and the driving mechanism.

' The primary pump 2 comprises. a body 23 located withiny and integral withA the bottom wall of a casing 24-which is open at the top and bolted to the underside of the pump housing I4. The interior of the casing 24 is open to the pump Ahousing 4, and adapted to receive and collect any fluid leaking into the latter from the pump body 5.

lThe body 23 is formed with a longitudinal pump cylinder 25 open at opposite ends tothe interior of the casing 24. A guide b0re'26 in spaced axial alignment with the cylinder 25 cylinders 1 open re yI4 to a plurality of im is-l'dsed-'t the outer end by an end plate 28 suitably bolted in position.

Formed in the cylinder 25 intermediate itsends is a peripheral groove 29 connected at opposite sides respectively through inlet vand outlet valves 30 and 3| to'supply and delivery passages 32 and 33. The inlet valve 30 comprises a bore defining a valve chamber,34 opening downwardly' in one side of the body 23 and connected through a passage 35 to the groove 29. A valve passage 36 intersects the supply passage 32 and opens' lduit 42 adapted for connection with a. suitable source of iiuid supply, such as a tank (not shownie- It will be understood that the valve 36 will open in responseto the intake pressure in the cylinder 25.

The outlet valve 3| comprises a bore deilning a valve chamber 43 in the other side of the body 23, and closed at the outer end by a screw cap 44.l

The chamber 43 intersects the delivery passage 33, and is connected to the groove 29 through a valve passage 45 encircled by an annular yalve seat 46. A valve member 41 is slidably guided in the cap 44, and is normally urged into engagement withdthe seat 46 by a compression spring 46. It will be understood that the valve 3| will operi in response to the delivery pressure ln the cylinder 25. The passage 33 opens to one end of the casing 23, and is connected through a screw iltting 49.to the line or conduit |9 leading to the inlet of the pump I.

The pump 2 also comprises a piston having a head 50 and a cup-shaped guide 5l interconnected by an axial stem 52. and reciproeable respectively in one end of the '.cylinder 25 and in the guide bore 26. Suitable openings 53 are formed in the connecting end wall of the guide to permit pressure relief in the bore 26. Preferably, the piston 50 is driven by the pump'l and hence in timed relation to the pistons 3. The drive comprises -a rocker lever 54 mounted intermediate its ends on a pin 55 in the casing 24 for oscillation about an axis extending transversely of the piston 50. The upper end of the lever 54 is rounded, and engages in a transverse notch 56 in the underside of the lowermost operating plunger The lower end of the lever 54 is similarly rounded, and engages in an annular groove 51 denned by the piston head 50 and a spaced ilange 56 integral with the stem 52.

Extending reciprocably into the end Yoi the cylinder 25 opposite the piston 50 is a pressure control plunger 59. This plunger is urged inwardly by spring pressure, and in eiect consti; tutes a yieldable end wall for the pressure chamthrough the pump body 23 and the end wall 21 and end plate 23 to the exterior of the casing 24 in parallel relation' to" thepinger 5t. V'and is normally in engagement with the adjacent end of the pump body. A priming lever 65 is pivotally mounted on a bracket 66 on the end plate the valve .3| during the pressure stroke.

26, and is provided with a lug 61 in abutment with the outer end of the rod 64. The lever 65 is normally heldin its outermost positionrby means-'of ajSPllllE 56. It will be evident that swinging the lever 65'inwardly againstl the rod 64 will cause the stop 60 throng engagement with the shoulder 62 to shift the pr ssure plunger 59 outwardly in a pumppriming stroke.

-Any suitable spring means may be provided for urging the4 plunger 59 inwardly. In the present instance, the 'plunger 59 is formed with an axial bore 69 opening to the outer end. A iloat bushing 16, having aninternal flange 1| deflning a.

spring seat, is slidable in the bore 69. A compres- Ision spring' 12 in the bore 65 engages one side of the seat 1|. A similar spring13 engages the other lside of the seat 1| and a stationary seat 14 mounted in the adjacent end wall of the casing A24. The bushing 10 permits the use of the two relatively short springs 12 and 13 which will notA tendto buckle objectionabiy or rub against the surface of the bore 69 as would be likely if a single long spring were employed in their stead. A third compression spring 15, encircling the spring 13 and also engaging the seat 14, acts directly against the outer end of the plunger 5I. 'Ihe three springs 12, 13and 15 all tend to urge the plunger 59 inwardly, and are provided in lieu of one spring in order to obtain the desired thrust pressure plunger 56 is operable automatically to vary the displacement of the pump 2 in accordance with the requirements of the pump at a predetermined maximum pressure. If the maxlmum displacement of the pump 2 is required, the springs 12, 13 and 15 will hold the shoulder 62 in engagement with the stop 60 to locate the pressure plunger 56 in its innermost position. In the event that the full displacement of the pump 2 is notrequired, the pressure in the cylinder 25 will cause the plunger 59 to'move outwardly during the pressure stroke of the piston 56 so that only part of the displacement of the piston will be discharged through the valve 3|. In the subsequent suction stroke, the plunger 56 will move inwardly to maintain the uid in the cylinder 25 under the predetermined maximum discharge pressure until the shoulder 62 again engages the stop 60, and thereafter ilmd in an amount suiilcient to'rell the cylinder 25 will enter'through the valve 30. It will therefore 'be evident that the pump is self-relieving.

The function oi the hand lever 65 andassociated Darts is to permit manual reciprocation of the plunger 59 independently of the piston 56 for the purpose of priming the injection system without cranking the engine. Hand 4priming is resorted to when for. any reason the system becomes air bound, for example, as a result of the fuel tank running dry.' The priming is accom- TheV v 2,810,370 plished by'working the lever 65 a sufcient number of full strokes to expel the air and' to till the system with oil under maximumprimary .pump

pressure. Thereafter, the springs 12, 13 and 15 will fail to move the plunger 59 to the left', thereby automatically renderingithe hand primingf fluid into the cylinder 25 during the suction stroke of the piston 50. In its preferred form, the pump 3 is built into the piston 50, and specifically comprises an axial cylinder bore 16 opening through the stem 52 and havingradial inlet ports 11 opening to the groove 51. The inner end of the bore 16 is adapted to discharge through an outlet valve 18 into the cylinder 25. A pumpplunger- 19 is reciprocable in the outer end of the bore 16, and is provided with an external head 89 normally held against the end plate 28 by a coiled compression spring 8|.

During the pressure stroke of the piston 50, the plunger 19is relatively retracted from the llore 16 to uncover the ports 11. If the fluid level in the casing 24 is at or above the ports 11, the fluid will enter and fill the pressure end of the bore 16. During the subsequent intake stroke of the piston 50, the plunger-,19 will be forced into t e -bore 16 in a pressure stroke to discharge the fluid past the valve 18. The capacity of the pump from entering the valve 18 and interfering with seating of the-valve member 90. In the event that the valve member 90 fails to seat, the ref striction also serves to insure continued delivery of fluid by the pump 2 so that when the pump.

structure is employed to supply fuelto'an engine the latter will nots'top for lack of fuel. I claim as myinvention:

1. A pump structure comprising, in..combina,

tion, a pump havinga chamber, a pump cylinder 4 open at one-end to said chamber and having uid supply and discharge means connected to the other end, a piston reciprocable in said cylinder and means in said chamber for driving said piston, and a second pump driven from said last mentioned means in timed relation to said first mentioned p ump and ,operable to return fluid leaking from said cylinder into said chamber back to said fluid supply means of said rst mentioned pump.L

' 2. .A pump structure comprising, in combination, a pump having pumping elements with fluid supply means and fluid discharge means and having an enclosing housing adapted to receive fluid 3 is sufliciently in excess of the normal leakage that the fluid level in the casing 24 will be automatically maintained atthe ports 11.

The leakage pump plunger 19 is formed with a peripheral groove 82 which is connected through radial bores 83 and7 an axial bore 84 to the innerend of the plunger, and which is movable into registration with the inlet ports 11 at'the end of the pressure stroke to relieve the pressure in the cylinder bore 16. I'he relief or by-pass determines the end point of pressure discharge by the Iplunger 19. Consequently, changes in the length 'of stroke of the piston 59 as would be obtained by substitution of swash plates I2. of different angularities, will not change the eifective capacity. of the pump 3. The effective portion of the pressure stroke of the lplunger 19 will remain constant l,

regardless of changes in the length of relative plunger travel. If the level of leakage fluid in the casing 24 is below the ports 11, the cylinder bore 16 will be charged with air., The relief or by-pass also serves to prevent excess movement of the plunger 19 from compressing the air to a pressure sufciently high to open the valve 18.

The valve 18 comprises a hollow body 85 threaded into an axial bore 86 in the working end of .the piston and connecting with 'the secured in the inner end of the body 85, and is clamped against the inner end Aedge of the bore 16 to dene in effect the end-wall of the latter. The

memberl is formed with va restricted valve port bore 16. The restriction of the portv 88 prevents large particles of dirt and other foreign matter cylinder bore 16. A tapered member 81 is rigidly .60

leaking from said elements, and a second pump driven in timed relation to said firstmentioned pump and operable to `return fluid leaking vfrom said elements back to said supply means.

3, A pump structure comprising,- in combination, .a relatively high pressure delivery pump having an inlet and an outlet, pumping means taking fluid from said inlet and discharging it to said outlet, a relatively low pressure pump having an inlet and having an outlet connected to said iirst mentioned inlet and having pumping means driven in timed relation to said first mentioned pumping means, means for collecting fluid leaking from both said pumping means, and n auxiliary pump driven in timed relation to said low pressure pump and operable to transfer fluid leaking from said two pumping means and collecting in said last mentioned means to sai'dlow pressure pump for return with a normal supply of fluid to said rst mentioned inlet'.

4. A pump structurecomprising. in combina-A tion, alcasing having an internaliiuid collecting i chamber and a pump cylinder, a piston reciprocable in said cylinder, means for supplying uid to said cylinder andfor discharging fluid from said cylinder in response to the .reciprocation of said piston, and an auxiliary pump operl able by said piston and adapted to transfer uid from said chamber to said cylinder.

5. A pump structure comprising, in combina-'4A tion, a casing having an internal fluid collecting chamber and a pump cylinder, a piston reciprocable in said cylinder, means forsupplying uid to saidcylinder during the suction stroke of 'said piston, means for discharging fluid from said cylinder in response to the pressure stroke of said piston, and an auxiliary pump operable in timed relation to said piston for discharging fluid from said chamber to said cylinder only during the 'suction stroke of saidl piston and independently of sad first mentioned means..

6. A pump comprising, in combination, a cas'- ing having an internal fluid collecting chamber cylinder, and a plunger relatively reciprocable in said auxiliary cylinder in response to the reciprocation oi' said piston and movable at the en'd of its v'suction stroke 'to uncover said inlet ports.

7; 'A pump comprising, in combination, a casing having an internal fluid collecting chamber and a body formed with a pump cylinder, means for discharging duid under pressure from said cylinder, apiston reciprocable in said cylinder and formed with an axial auxiliary cylinder hav- :ing an inlet port opening to said chamber and having means including an outlet check valve discharging to said pump cylinder, and a plunger vrelatively reciprocable vin said auxiliary cylinder andavo piston guided for power reciprocation in said cylinder, an axial cylinder bore opening to one end of said piston and having an inlet port in one side` open to said reservoir and an outlet discharging to said cylinder, a pumpplunger extending reciprocably into said bore, and spring means alternate pressure and intake strokes relative to returning fluid leaking from said elements back to said supply means.

9. In combination, a high pressure pump of the pulsating type having pump elements withlow pressure pump of the constant pressure type for supplying duid to said supply means and a pump for supplying duid leaking from said elements to said low pressure pump for return to said supply means.

10. In combination, a high pressure pump oi the pulsating type having pump elements with duid supply means and duid discharge means. a low pressure pump normally of the constant pressure type for supplying duid to said supply means, power drive means for operating said low pressure pump in timed relation to said high pressure pump, and means for manually camerating said low pressure pump independently oi' said high pressure pump to deliver duid to said simply means.

ll. In combination, a high pressure variable.

delivery pump of the pulsating type having pump elements with duid supply means and duid discharge means, and a low pressure pump having duid delivery means connected to said duid sup* 'pl'y means and having self-relieving means for varying the, effective displacement and limiting the delivery pressure of the duid displaced, whereby to provide a volume delivery variable in accordance with the demands of said drst mentioned pump.

12. In a pump structure, in combination, a

pump cylinder having inlet and outlet means, a

4piston extending` sl'idably into one end of said iary cylinder, and in the other direction `ot movement an intake phase in' said cylinder and a discharge phase in said auxiliary cylinder.

13. A pump structure comprising in combinationwith a duid reservoir. a dxed cylinder mountsaid bore as an incident to the reciprocation of said piston, said plunger uncovering said port at the end ot each intake stroke to admit duid from said reservoir to said bore, and covering said port during each pressure stroke to' discharge duid under pressure i'r'om said bore.

14. A pump .structure 'comprising in cmbination with a duidreservoir, a cylinder located horizontally in the bottom or -said reservoir, a piston reciprocable at one end in said cylinder and having at the other end a cylinder bore with an inlet port in one side open to said reservoir, an outlet check valve opening from said cylinder bore to said cylinder, a pump plunger extending for relative reciprocation into said bore, spring means tending to urge said plunger out of said bore, said plunger uncovering said port at the end oi. each intake stroke to admit duid from said reservoir to said bore, and'means for relieving said bore to said reservoir at the end of the pressure stroke of said plunger.

l5. A pump comprising in combination with a duid reservoir, a cylinder body mounted horizontally in the vbottom of said reservoir and guided ed'horlzontally in the bottom oi said reservoir, a 75 ing an inlet port in one side open to said reser' voir, a pump plunger extending reciprocably into said bore, spring means tending to urse said plunger out of `said bore and to maintain said plunger in a fixed position for alternate pressure and intake strokes relative to said bore as an incident lto the reciprocation of said body. said plunger uncoveringl said port at the end of each intake stroke to admit duid from said reservoir to said bore., and means for discharging duid under pressure-from said bore in response to the pressure stroke of sai'd plunger.

16. A pump comprising in combination with a duid reservoir, a body located horizontally in the bottom of said reservoir and having a cylinder bore with an inlet port in one side open to said reservoir, a pump plunger extending i'or relative reciprocation into said bore, spring means tedding to urge said plunger out oi said bore, said, plunger uncovering said port at the end of each intake stroke to admit duid from said reservoir to saidI bore, a discharge e having an outwardly opening valve` seat and a restricted port opening from'isaid bore in spaced relation to said seat, an outlet check valve member adapted to engage said seat, and spning means tending to hold said member against said seat with a pressure sudlcientto prevent liiting of said member .v

by any gas pressure created in said bore.

17. In a pump structure, in combinationfa. high pressure pump having a pump element with`-- ually operating said self-relieving means to effect the delivery of fluid from said low pressure pump to said fluid supply means independently of operation of said low pressure pump by said power drive means.4

18. In a pump structure, in combination, a high pressure pump having fluid supply means and fluid discharge means, a low pressure pump having a cylinder, a pump piston reciprocable in one end of said cylinder and a self-relieving piston in the other end of said cylinder for limiting the delivery pressure to provide a volum'e delivery variable in accordance with the demands of said first mentioned pump, said cylinder having fluid inlet means and having fluid outlet means' adapted to receive the fluid displaced by either of said pistons, power drive means for operating said pump piston in timed relation to said high pressure pump, and means'for manually operating said self-relieving piston independently. of

. said power drive means.

.taking fiuid from said inlet and discharging it to said outlet, and means for collecting fluid leaking from said pumping means, a. relatively low pressure pump having an inlet and having an outletconnected to said first mentioned inlet and having pumping means driven in timed relation to said first mentioned pumping means, and an auxiliary pump driven in timed relation to said low pressure pump and operable to transfer fluid leaking from said first mentioned pumping means and collecting in said second ment oned means to said low pressure pump for retur with a normal supply of fluid to said first mentioned inlet.

2l. A pump structure comprising, in combination, a metering pump having a supply inlet and a delivery outlet, piston means adapted to adjustably alter the effective displacement of said metering pump irrespective of the pressure in said delivery outlet, a second pump adapted to supply fiuid to said supply inlet of said metering pump,.. said second pump including a plunger having a constant length of stroke but of variable effective displacement inversely responsive to the pressure of fluid supplied by said second pump, a sump associated with said rst and second pumps, and a third pump comprising a plunger of constant stroke and fixed effective displacement adapted to transfer fluid from said sump to the supply inlet of said first pump against and irrespective of the pressure of fluid delivered by said second pump.

JAMES F. HOFFER.

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