US2620734A

US2620734A - Constant delivery pump

Info

Publication number: US2620734A
Application number: US27294A
Authority: US
Inventors: Saalfrank Royal Bartlett
Original assignee: Milton Roy LLC
Current assignee: Milton Roy LLC
Priority date: 1948-05-15
Filing date: 1948-05-15
Publication date: 1952-12-09
Anticipated expiration: 1969-12-09

Description

Dec. 9, 1952 R. B. sAALFRANK CONSTANT DELIVERY PUMP Filed May 15. 1948- 10 Sheets-Sheet l R. B. SAALFRANK 2,620,734

- CONSTANT v(DELIVERY PUMP l0 Sheets-Sheet 2 Dec. 9, 1952 Fileyd "May 15. 19148 Dec. 9, 1952 R. B. SAALFRANK CONSTANT DELIVERY PUMP Filed My '15. 1948 10 Sheets-Sheet 3 Dec. 9, 1952 R. B. SAALFRANK 2,620,734

CONSTANT DELIVERY PUMP Filed May 15, 1948 1o sheets-sheet 4 Ill I lll Dec. 9, 1952 R. B. sAALr-'RANK CONSTANT DELIVERY PUMP 10 Sheets-Sheet 5 Filed May 15, 1948 www Www(

Dec. 9, 1952 Filed May 15. 1948 R. B. SAALFRANK CONSTANT DELIVERY PUMP 1`o sheets-sheet e Dec- 9, 1952' R. B. SAALFRANK 2,520,734

CONSTANT DELIVERY. PUMP Filed May 15. 1948 10 Sheets-Sheet 7 ATTORNEY-5.

Dec. 9, 1952 Filed May 15, 194s f .EL

INVENTOR @yA-f De@ 9, l952 t R. B. SAALFRANK 2,620,734

` CONSTANT DELIVERY PUMP Filed May 1`5, 194s 1o sheets-sheet 9 N l* N I w lf ff" "Q f1 t Q TTORNEY5,

Dec. 9, 1952 Filed May 15, 194s Patented Dec. 9, 1 952 CONSTANT DELIVERY PUMP Royal Bartlett Saalfrank, Gulfport, Fla., assignor to Milton Roy Company, Chestnut Hill, Pa., a corporation of Pennsylvania Application May 15, 1948, Serial No. 27,294

9 Claims. (Cl. 10S-38) The present invention relates to constant delivery pumps.

A further purpose of the invention is to simplify and improve the construction of constant delivery pumps in which a plurality of pumps in out-of-phase relationship are pumping from the same inlet to the same discharge, and provisions are made for variation in the now rate while maintaining uniformity at any given ow rate. f

A further purpose is to avoid ithe extremely high tolerances and expensive machining which have been required in the production of constant delivery pumps, while improving the accuracy and reliability of the mechanisms.

A further purpose in a constant delivery pump employing a plurality of pumps each having a cylinder, a piston in the cylinderand an inlet and outlet connection to the cylinder, vwith common uid connections to the inlets and outlets to all'cylinders, is to provide a link or the like for controlling the motion-of each piston, which link bears the same angular relation to each piston and is pivotally supported.

A further purpose is to drive the links for the respective pistons by cams out of phase with one another, and to the pumping stroke of another link, and to mechanically connect each link to its piston by an adjustment.

A further purpose is to adjust the mechanical connection between each link and its piston with respect to the pivotal support of each link, and preferably to adjust all links in unison to vary the throw of all pistons in unison.

A further purpose is to pivot the links ea-ch at a plurality ofspaced points.

A further purpose is to provide an adjustment slot in each link, and means for varying the mechanical connection Awith the adjustment slot along a line which maintains the same angular y.relation with respect to the piston for any adjustment at at least .one` position in thestroke andrwhich atcorresponding positions maintains the sam-e angular relation With respect to each piston. 1' l A further purpose is to provide anapproach portion at the beginning of the pumping stroke on each cam which is .added to the uniform motion curve (and desirably also add to the dwell) 4and-to correspondinglyy subtract from the uni- -v lform motion curve of vthe endfof the pumping vstroke on each cam l(and-desirably also subtract from the dwell) and to overlap the cam portions so as to givelgradual acceleration and l.gradual deceleration'of 'the pistonsv and other moving parts. V

A further purpose is to provide correction for lost motion by lowering the base line of the cam.

A further purpose is to 'add a correction for Valve slippage, for stroke length below optimum, for piston speed below optimum, and forpiston diameter below optimum, on the pumping stroke.

A further purpose is to add a correction for uid compressibility throughout the pumping stroke of each cam. y

A further purpose is to retard the retraction stroke on each cam to avoid volatilization of the liquid pumped when pumping volatile liquids .as compared to the retraction stroke when pumping non-volatile liquids.

A further purpose is to drive through face cams preferably mounted and rotating as a single unit.

A further purpose is to drive through a rocker parallelogram having equal parallel rockers and an intermediate link which follows a cam and transmits the motion.

A further purpose is to employ plunger type crossheads in prolongation of the pump pistons, and to inter-relate the crossheads to one another during motion to prevent rotation.

A further purpose is to drive a constant delivery pump from a camto a rocker parallelogram, from the rocker parallelograrn by` a sliding pivot, movable transversely to the piston line of motion, to the swinging end of an adjustment rocker having a pivot, movable toward and away from the line of piston motion, and by a sliding pivot on the adjustment rocker to the piston crosshead.

A further purpose is to provide common and coaxial support for the adjustment rockers 'of a plurality of pumps. Y

A further purpose is to provide coaxial pivot support for the end rockers of therockerparallelograms for a plurality of pumps.

A further purpose is to carry the piston tothe same position at ythe end of the stroke in each pump regardless of variation in stroke length, to correct for compressibilityfo'f liquid, preferably by inclining the adjustmentv slot in each link at an angle to the Ypiston which corresponds with the Vangle of the adiustr'nentrocker at the end of the stroke, and making the adjustment along a line corresponding to the line .of the adjustment rocker at the endof thestr'oke.

A further purpose is to operatev a-rocker-by a link from a cam for each piston, to connect an adjustment-slot on the rocker to the free end of an adjustment rocker and to connect the free end of the adjustment rocker to a transverse slot on the piston plunger.

Further purposes appear in the specification and in the claims.

In the drawings I havechosen to illustrate a few only of the embodiments in which this invention may appear, choosing the forms shown from the standpoints of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.

Figure 1 is a top plan view of a constant delivery pump of the present invention with the cover removed.

Figure 2 is a longitudinal section on the line 2 2 of Figure 1.

Figure 3 is a transverse section on the line 3-3 of Figure 2.

Figure 4 is a fragmentary exploded perspective showing the operating mechanism.

Figure 5 is an axial sectional perspective of the cam unit.

Figure 6 is a diagram'of the inlet and discharge.

Figure 7 is a cam diagram showing the cam throw or follower 'motion on the pumping stroke as the ordinate, plotted against angle of rotation of the cam as the abscissa. This diagram shows the correction for gradual acceleration and deceleration of the pistons.

Figure 8 is a cam diagram corresponding to Figure 7 showing the correction for lost motion. This and the remaining diagrams of this type show only a .single cam track, whereas Figure '7 shows the tracks of both cams, which are out-oiphase opposite counterparts.

Figure 9 is a cam diagram corresponding to 'Figure 7 showing the correction `for valve slippage.

Figure 10 is a cam diagram corresponding to Figure 7 showing the correction for stroke length below optimum.

Figure 11 is a cam diagram corresponding to Figure 7 showing the correction for fluid compressibility.

Figure l2 is a cam diagram corresponding to Figure 7 .showing the correction for piston diameter below optimum.

Figure 13 is a cam diagram corresponding to Figure 7 showing 'the correction for speed below optimum.

Figure 14 is a circle diagram illustrating dia- .grammatica-lly the .correction for the arc or the rockers which support each link.

Figure 15 is a .cam diagram similarto Figure '7 showing the change in the return stroke when pumping a volatile liquid.

Figure 16 is a pair of overlapped curves showing the volume of discharge from the two pumps r Y' plotted against angle of cam motion.

Figure `17 is a view corresponding to .Figure 2 showing a modification of the form of Figures 1 .to 6 inclusive.

Figures 18 and 19 illustrate a further modication of the form of Figures l to 6J Figure 18 being an elevation of the mechanism for the operation of one pump, and Figure 19 being an exploded perspective of such mechanism.

Except for the features lmodied the device of Figure 17 andthe device of Figures 18 and 19 correspond to the device of Figures 1 to 6 inclusive.

Describing in illustration but not in limitation l and referring to the drawings:

The present `invention is a further development .and improvement of the subject matter of Apatent application Serial No. 778,316, led by me jointly with Milton Roy Sheen, deceased, and Robert T. Sheen, for Constant Delivery Pump.

4 led October '7, 1947, now abandoned, which is incorporated herein by reference and made a part hereof.

In constant delivery pumps, in order to obtain a delivery curve which is constant within a high degree of accuracy with variation in discharge, it has been necessary in the' past to employ mechanism which entails expensive and complicated machining, with high tolerances throughout, and which is necessarily expensive to produce and dicult to maintain. By the present invention the mechanism required is greatly simplied, the machine operations are markedly reduced both in number and, complexity, and the di'ioulty through maintenance is minimized, without, however, departing from the high accuracy previously obtained, and in fact with improvement in both accuracy and reliability.

By the present invention it is possible to obtain very accurate adjustment without employing mechanical devices such as constantly sliding power transfer members which are difficult to produce and likely to be subject to wear. A suitably pivoted member such as a link is preferably employed for driving each piston of a plurality of pumps which have a common inlet connection and a com-mon outlet connection (the connections may be internal or external). The link or other pivoted member is movable in a path which bears the same angular `relation to each piston, and the respective links for the different pistons are cam operated `out of phase with respect to one another and with the pumping stroke of one link displaced with respect to the pumping stroke of another link.

A mechanical connection extends from each link to its piston, and this connection is adjustable with respect to the pivotal support of the link, the adjustment being preferably common for all links and capable of varying all links in unison. The links are preferably mounted on pivoted rockers at spaced points. The adjustment preferably includes an adjustment slot and an adjustment in the `slot which accomplishes adjustment on a line which maintains the same angular relation with respect to the piston for any adjustment at at least one position in the stroke and which line at corresponding positions maintains the same angular relation with respect to Vthe corresponding piston. It is therefore possible to make linear or uniform adjustment and to record the same .on a dial or the like reading linearly, without necessity for numerous dial corrections .or for non-uniform dials. And a remote control or other automatic device can linearly .change the gadjustment as required.

The present device .in the preferred embodiment transmits cam Ymotion through a rocker parallelogram whose link maintains parallelism with the line of piston motion, and which preferably makes sliding pivot connection with the swinging end of an adjustment rocker whose pivot is moved toward and away from the line of piston motion, and which in turn makes sliding pivot connection with a plunger-type crosshead in prolongation of and connected with the piston.

The cams are preferably separate cams for each pump which are 'united together as .a cam unit.

As shown iin 'Figures 1 to 5 inclusive, the pumps comprise a pair of separate reciprocating piston pumps 20 and `2l having .common inlet at 22 -(Figure 6) .and common outlet at 23. Inlet 24 to each :individual pump `occurs through 4 passages containing a `plurality (preferably two) ball chBClS Valves and 26 on seats and arranged -in series and discharging into a pump cylinder 21. Discharge in the individual pump from the pump cylinder takes place through passages containing a plurality (preferably two) successive

ball check valves

30 and 3| on seats and connecting to an individual discharge 32 from each pump. Access to the balls and seats of the respective check valves is conveniently provided through a removable cover plate 33 fastened and gasketed in any suitable way not shown. In each pump cylinder is located a piston 34 extending through packing 35 compressed by a packing gland 36. The pistonk preferably has an enlarged attachment head 31 for connection to operating mechamsm.

Each pump will desirably be of the character set forth in Milton Roy Sheen U. S. Patents Nos. 2,263,429 for Pump, issued November 18, 1941, and 2,367,893 for Liquid Pump, issued January 23, 1945. It will be understood that other suitable pumps may be employed.

In order to accomplish constant delivery, a plurality of pumps are connected to the same inlet and the same discharge, and are arranged out of phase so that generally-when one pump is on the exhaust, another pump is on the discharge stroke. In the preferred embodiment of the invention, two pumps will be used, although some Ahigher number might be employed, and with two pumps the pumps will preferably be 180 out of phase. The pumps will be arranged adjacent to one another with the line of travel of the pistons in the preferred embodiment parallel and the pistons extending out of the open ends of the cylinders, preferably in the same direction (not in opposite directions). The vdriving and adjusting mechanism is contained in a housing 40 which is provided with a bracket extension 4| on which the pumps are mounted. The extension has a well 42 which is carried up as high as desired to provide for catching of leakage or for holding a liquid sealing bath, if thisl be desired.

Extending in prolongation of each piston is one of two duplicate plunger-like driving crossheads 43, united to the corresponding pistonv by a, locking collar 44 around thev attachment head 31. While each crosshead 43 is of circular shape Yand resembles a plunger, it is guided to perform a crosshead function. The crossheads 43 are guided at the forward or pump end of the housing at 45 and at the opposite or rear end at 46, for sliding motion back and forth on the axis of each piston. The wide spacing of the guides makes high tolerance in the guides unnecessary. A plug 41 closes the guiding opening at 46.

In order to prevent undesired rotation of the crossheads, each crosshead carries a crosshead interlocking guide 50 having a. collar` portion 5| provided with a set screw for locking on one crosshead, and guiding fingers 52 for extending around the other crosshead. Thus the crossheads can slide back and forth freely without being permitted to turn.

Motion is submitted to each crosshead by an adjustment rocker 53. Each rockeris pivotally supported at 54 coaxial with respect to the other adjustment rocker, the axis being located at one side of the lines of motion of the pump pistons and the axis extending transversely to the lines of motion of the pump pistons and in a direction to permit the rocker ends to swing back and forth with the crossheads. The adjustment rockers are as shown opposite counterparts of equal length, and toward their outer or rocking ends each adjustment rocker makes sliding pivot contact with a pivot pin 55 in a crosshead. The positions of the pivot pins 55 with respect to the crossheads are the same distance from the piston for each crosshead. Each pivot pin isconveniently secured as by a nut 56, and carries at its end toward the adjustment rocker a pivot block 51 which turns on the pin 55. Each block 51 slides in a slot or guideway 60 extending longitudinally of each adjustment rocker. Thus each adjustment rocker maintains a driving connection with the corresponding crosshead through the sliding connection made by the guideway 60, the block 51 and the pin 55 for each pump.

The adjustment rocker pivots are mounted on a support 6| having bearings 62 which are preferably surrounded on each side -by cooperating bearings 63 on the adjustment rockers, the

bearings

62 and 63 receiving pivot pins at 54. The adjustment support 6| is guided for motion transversely to the line of motion of the piston and toward or away from the same to change the volume of discharge of the constant delivery pump by sliding bearings 64 (preferably at the four corners) which engage guide rods `65 mounted at the bottom in lugs 66 on the inside of the housing and mounted at the top in a spider 61 which is fastened as by bolts 10 to the interior of the hous- 111g.

The support 6| moves up and down in its guides under the action of an adjusting screw 1| journalled in bearings 12 in the spider and provided with driving connection, preferably through a. dog-type clutch 13 driven manually or mechanically from an adjustment drive 14 supported on a cap 1-5 of the housing. The adjustment drive may be manual or mechanical, direct or remote, as later explained, but here is shown as a manual adjustment through gearing of well known character operated by a crank handle 16. A suitable dial not shown may indicate the adjustment position.

,The range of motion of the support 6| away from the lines of piston motion under the action of the screw 1| is limited by adjustable stop screws 11 on the spider which engage abutments on the support. Motion in the opposite direction of adjustment is limited by the contact of the adjusting screws 80 on the support 6| against the lug 802 on the housing.

The rocker motion of the adjustment rockers is caused by a sliding connection made with a rocker parallelogram. Preferably located on the outer end of each adjustment rocker, and therefore on a greater radius than the sliding connection with the corresponding crosshead, is a sliding pivot connection with a link 8| by means of a pin 82 secured by a nut 83 and making pivotal connection to a block llvsliding in a slot or guideway 85 extending transversely to the line of piston motion in each link 8|. Thus as the adjustment rocker pivots are moved toward and away from the line of piston motion the eiective rocker arm of the adjustment rockers acting on the crossheads changes equally for each pump, while the effective rocker arm by which each adjustment rocker is driven by its link 8| of the rocker parallelogram remains unchanged, since the guideways 85 are transverse to the direction of motion of the links.

The links 8| maintain a direction parallel to the direction of the pistons during the motion of the links due to the action of

parallelogram rockers

86 and 81, at the ends of each link. The

rockers

86 and 81 are of equal length. Within each rocker parallelogram, the rockers are parallel to one another. In,v the twoparallelograms (oneA for each pump) the rockersY 35 are preferably coaxial andy the rockers S1 are preferably coaxial. The rockers 36 turn freely about shaft 90 extending across the housing and the rockers El similarly turn freely about shaft 9i similarly supported. The shafts 90 and 9| are preferably supported at their extreme ends so that slight variations in the supporting positions will make little difference in the accuracy of positioning of the rockers. The shafts 9B and 9i as shown are at equal distances fromthe line of piston motion. Each link 8| makes pivot connection with a rocker t at S2 and with a rocker all at S3 near the ends of the link.

Thus it will be seenV that the link rockers of each set make in effect a parallelogram, since the center distance between the4 rocker shafts 90 and 9| are the same as the center distances between the link pivotal connections si and 93 and the rocker arms of the two rockers are equal.

Although the links move outof phase with one another, each link in the preferred embodiment always moves in a direction parallel with the axis of its piston.

The motion of the rocker parallelograms is imparted by cams which are preferably face cams arranged and operating as a single unit. As best seen in Figure 5, cams and 95 have cam tracks 36 preferably facing inwardly and are separated by spacers 91 and il and by a driving gear le! between the spacers. The entire unit is united by pins |02 and has an internal bearing sleeve iS. Each cam track 9e cooperates with 'a cam follower itil, conveniently arranged on the pivot connection 93 between the link and rocker 3l so that the parallelogram moves back and forth in response to the camV track.

rfhe cam unit is conveniently driven from an electric motor through a yspeed reducer and worm drive. For this purpose the gear |il| will suitably be a worm wheel. The worm wheel and cam unit turns on shaft |35 (which is itself stationary) transverse to the axis of the pistons. A worm me on a shaft IG'E intermeshes with the worm wheel ll. The thrust from the worm is taken by a thrust bearing i in (Figure 2) and the shaft W? is suitably journalled at one end i|| in a spider H2 supported from the housing and at the other end in a lug i3 on the interior of the housing. rEhe shaft it? is reduced in section at ||4 to clear the crossheads. Drive to the shaft |01 is accomplished in any suitable way, conveniently from an electric motor i i5 on a vertical axis supported in the top l5 of the housing, driving by a convenient separable dog type clutch to a stub shaft journalled at |2 in the spider l2 and carrying a pinion |21. The pinion i2| meshes with a gear |22 on a shaft |23 journalling at |24 in the spider and carrying at its opposite end a pinion |25. The pinion |25 meshes with a gear |26 on the worm shaft |07.

The gear spider H2 is conveniently made removable and the gears are themselves readily removable so that gears can be changed as required to vary the speed reduction from the motor.

It will be noted that the rear end of the crossheads is carried back beyond the speed reduction to provide widely spaced sliding support for the orossheads, so that a slight variation in the centers of the crossheads will not produce a serious error and excessively high tolerances in the boring of the guides will not be required. Throughout the mechanism where possible widely spaced 8,' points of shaft .support 'are provided on critical Components.

wear can be reduced to a minimum by running the mechanism in oil, which fills the interior of the housing suitably up to a level above the speed reduction gears.

It will be evident that in the preferred embodiment the shafts are stationary, and supported at widely spaced points, so that a slight tolerance variation in the support location will not seriously affect the mechanism. Except for the pistons and orossheads, no sliding parts in constant motion are employed.

It will be understood that the pair of face cams provide a unit which can be replaced whenever diiferent operating cam characteristics are required. rlhus if desired, the cam rocker parallelogram can be employed with variation in the cams if required for operation by the pump on markedly different liquids.

The cams include the fundamental uniform motion, which is laid out on each cam substantially out of phase.

In accordance with the invention, the cams permit correction for stroke length, working pressure, speed, volume, and fluid viscosity. A gradual approach curve to the pumping stroke is permitted to reduce harshness of operation and permit greater speed. Adjustment for a low o perating pressure angle is also made on the cams. The cams likewise permit compensation for lost motion in the mechanism, overlap of pistons due to valve slippage, and correction for compressibility of the residual Volume of fluid. Likewise the cams permit adjustment of the working plunger for any suck back through the valve seat by the returning plunger. There is thus a full range of adjustment, and different sets of cams may be used Whenever any Vone of the factors changes.

It is very desirable to keep the pressure angle below 25. The most diffiult condition is created at the inception of the pressure stroke on the cam. Each cam is adjusted at this point to give an acceleration approximately equal t0 the acceleration of gravity. It is necessary to add stroke increments to one side of a cam equal to stroke increments removed from the other side of the carnand to. orient the two cams 180 out of phase so that a uniform pump delivery will be produced.

This correction vcan be distributed over 60, that is 30 on one cam to the point where the pressure angle would become too high (exceed 25), plus 30 to adjust the matching slope on the opposing cam. As seen in Figure '7, curve |30 plots cam rise against angle of rotation for uncorrected uniform motion on the pressure stroke only for one cam, and curve |3| does the same Yfor the other cam, the dividing line between the plots for the two cams being at |32, which is the base 'line for the cam depicted by curve |30.

With unorreeted uniform motion, the throw at the point where the correction would end is |33. An amount of motion onefhalf of this requirement is established at |34 at the original zero point von rotation of one cam, and a new zero point |35 is established 30 behind the original rero and on the dwell. A modified cam surface is now run from |35 Vto |36, which coincides with |34, and then to |31, where it intersects the uniform uncorreeted motion curve |30. This correction gives a gradual acceleration of added at 4|, and a corresponding correction is subtracted at |42 at the end of the pumping stroke on cam curve |30. y

Thus the opposite cam has amounts of motion yadded to its uniform motion increments equal and opposite to those subtracted from the uniform motion increments of the high side of the other cam. This has the eilect of gradually slowing down the motionof the piston at the end of the stroke, since the partial load is picked 1 up by the other piston at an earlier point.

Correction is also made for lost motion inherent in the parts. This correction is determined experimentally to be 0.002 inch per bearing or 0.015 inch total in the device. The stroke is increased by this amount by lowering the radius of the low dwell |32 toA |43 in Figure 8 and slightly varying ythe slope of thecorrective curve |44 at the beginning` of the 'pumping stroke, with the same corrective curve |431 added at the end of the return stroke of the same cam. Dwells are shown at |432 and |433.

. An additive correction |45 for valve slippage is included on the pumping stroke opposite the valve slippage point as shown inFigure 9. A similar additive correction is applied 1 on the other cam. As shown in VFigure 10, an additive correction |41 is made onrthe pumping stroke for stroke :length below optimum, with a similar additive correction on the other cam not shown.

For fluid compressibility, an additive correction |49 (Figure 11) is made progressively decreasing all along the stroke. There is a similar additive correction on the other cam.

In'Figures 9 to 11, the corrections shown on Figure 7 .are omitted for convenience.

As shown in Figure 12, an additive correction |52 is made for piston diameter below optimum on the pumping stroke opposite the point of valve operating in the other cylinder. A similar additivecorrection is made. on the other cam, not shown.

Figure 13 shows another additive correction |54 on the pumping stroke, in thisrcase for speed below optimum.; The opposite cam has a similar additive correction. i y

As well known in the mechanical arts,rthe fact that in vthe preferred embodiment the cam followers are on rockers rather than moving truly radially to the camcenter necessitates another correction in the cam which is purely geometricalin its purpose. Thus if on a cam path-|56 turning about a center |51 a radial follower would at certain times reach points |58, |59 and |60, but the particular rocker follower would be at points IBI, |62, and |63, the cam path is modied in any well known way to move the follower to pointsll, |62 and |63when the angular position corresponds to following of points |58, |59 and |60. The time increment of motion is stretchedout to allow the follower to reach points |61, |62and |63. A 'A Figure 15 `shows a, campath |64A for the yfull l stroke having a pressure stroke'from |65 to |66. a dwell from |66 tor|61and asuction stroke from |61 tov |68.' `For nonvolatile liquids the l YearnA suction stroke drops off rapidly-'at first'y at |69, but for volatile liquids, to avoid flashing into vapor, the' drop of the cam path is made more gradual at |10.

In the preferred form when the various cor- `rections are applied, all increments in pumping Ystroke due to a given piston give equal speeds of delivery, vand all increments of overlapped pumping strokes of two or more pistons vgive combined total delivery whichequals all other increments.

By these various corrections it has been found in practice that the ow .curve at the discharge is extremely` uniform and no appreciable indication is obtained of variation'corresponding to the end of one cycle and the beginning of another.

In operation at anygiven adjustment position, the motor drives through the speed'reduction to the worm and worm wheel, which turns the cam unit so that (with exception of the short angular period of overlap) ione pump is always ,on discharge .when another oneis on suction. Each cam manipulates'its follower. to move the rocker p'arall'elogranl of the correspondingpump back and forth, keeping therocker'motion always parallel to the piston axis andkeeping the adjustment slot. of the particular rocker always transverse to the piston axis.

"Each parallelogram" link moves the end of its adjustment rocker. back and forth and carries the corresponding interconnected crosshead and piston through the pumping cycle, the stroke being determined by the position of the pivot pin 55 on each "crosshead" with respect to the pivot 54.1 In other words, if the pivot 54 is down close to the pivot pin 55, the stroke will be short and the volume' of. delivery in' each pump will be low,

' although the adjustment rocker. for each pump always moves back andforth through the same ang'le for. a given cam' unit. To change the stroke of the adjustmentv rocker it is necessary to replace the cam unit by another cam unit, and this To change the timing of the cycle, the motor speed or, the 'speed reductionwillbechangedf I.' f M For any given motor speed, speed reduction andcam unit, a wide variation'in the volume of delivery can be accomplished during the operation of the pump Without stoppingthe mechanism or interfering with delivery. To do this it isv merely necessary.. to 'move' the adjustment rocker pivots 54 closer to the pivot. connections 55 tothe crossheads to shorten the stroke and reduce thevolume of delivery; orfarther from such pivot. connections 55t'o increase the stroke and increase the delivery. This adjustment is conveniently made by turning'the screw by hand or power and directly or by remote control. Any suitable electric, pneumatic, hydraulic or other remotedrive may be used. to'move the screw up or down and obtain therequi-red length ofv stroke. It will be understood, ofcourse, that both pumps are adjusted simultaneously .and to the same eX- tent by adjustment of the screw.

I-t willbe evident that by the present invention in the preferred* .embodiment-g the adjustable vstroke drive of a vplurality ofpumps Yhaving a common inlet Vand acommon discharge is controlled Vby cam means vwhich operates a plurality Amaintains the same angular relation with respect to each piston for any adjustment at at least one position in thestroke and which at that position reached at Ydifferent .timesin dilerent pumps bears theysame angular relation to the corresponding piston..

Figure 17. shows a lmodic'ation of. Figure 2 in which the adjustment slots 85. are on an angle to the piston which vcorresponds with the angle of eachadjustment rocker53 with its pistonat the forward end of its stroke. l .The adjustment support .6| and its guide rodsBS are cantedon the same angle, so that all Vadjustment .takes place along this line. By this devicev the piston is alwaysheld at thev same forward. position in the cylinder `at the end .of the stroke, whether the stroke is long or .short (even at zero stroke). This gives predetermined and very much reduced compressibility of liquid at the end of vthe. stroke, and variation in ysuch.comp'ressibility of the liquid with stroke change may cause an error at very high pressures. j

It will be evident that 'in this form the angle of the adjustment rocker in the'iorward position, the angleor the4 adjustment .'slot, .and the angle of the parallelogram rockersin rear position equals in each Vcase the angle of the line of adjustment, with respect to the piston.

In the form shown in Figures 18 and v19, each piston .plunger. .43 carries suitably .transverse thereto. a slot l 1'5. An adjustment support 6| suitablyadjustedv as in the other forms pivotally mounts Yanadjustnent rocker |16 pivoted'at |11 and carryinga'stud |18. On' one side the stud H. pivotallyac'onnect's to a sliding .block |19 which adjustably .movesin theslot of the piston plunger. At.' thexother end thestud '|18 carries `'a similar `adjustmentblock which pivotally connects in`an adjustmentV slot 4|80 yof a rocker |8| havinga'xed pivot at .|82 and pivotally connected by a link '|83 .tothe .cam follower ||J4. The link .|'83Lcarriesaycke |84-which rides the cam'pivot'andispivotally connected to the rockerll at |85. j

In view of my invention and disclosure variations and 'modifications to meet individual whim or particular need will doubtless become evident to others skilledintheartto obtain all or part of the benefits ofmy invention without copying the structure shown, yand I, therefore, claim. all such insofar astheyffall within'the reasonable spirit and scope of my claims.

Havi'ngvthus described my'invention what I claim as new anddesire to secure by Letters Patent is: i

1, In a constant""delivery`-pumpja plurality of pumps each having a cylinder, a vpiston in the cylinder, and an inletandoutlet connection including check valves Y'te the cylinder, 'there being a common liuidc'onnection 4tothe inlets and a common fluid connection to the outlets of the 112 cylinders, a link for each piston movablein a path which bears the samer angular relation to each piston, pivotal support forV eachY link, cam means for driving the links out of phase with Arespect to one another and with the pumping stroke of one link displaced with respect to the pumping stroke of another link, and a mechanical connection from each link to its piston adjustable with respect to the pivotal support for each linkin linear proportion between the adjustment and the change in the piston throw. Y

2. In a constant delivery pump, a plurality of pumps each having va cylinder, a piston in the cylinder, and an inlet and outlet-connection including check valves to the cylinder, -therevbeing a common fluid connection tothe inlets Vand `a common fluid connection vtoV the Voutlets of the cylinders, a link for-each piston movable-ina path which bears the 'same Vangular `relation to each piston, Vpivo't'ed` rockers supporting each link vvatal plurality of spaced points, cam mechanism for -driving the links out of pliase'with respecttoone another and Withthe pumping stroke-of onel link displaced with respect to the-pumping 'stroke of another link, amechanieal'connection from each link to its piston, "and an adjustment common to all links and varying in unison 'the throw Aof all pistons `by the mechanical 'connections by varying the position of each mechanicalconnection to the rocker pivots'o'f eaclr linkin linear proportion between the Ycommon adjustment and the 4change in the piston throw.

3. In a 'constant delivery pump, a pluralityof vpumps each lhaving a'cylinder, a piston inthe cylinder, Yand an `inlet 4and outlet connection including 'check valves to the cylinder, there being a common fluid connection to the 'inlets and acommon iiuid connection vto theoutlets of the cylinders, 'a link for eachpston movable in a path which 'bears the same "angular relation to each piston, pivotal support 'for 'each link, walls forming an Vadjustment slot'in each link, cam means for driving -the links out 'of phase with respect 'to one another andwith the pumping stroke orv one link 'displaced 'with respect' to the Apumping stroke of vanother "lin-k, a 4mechanical connection Vbetween lthe adjustment slot'of each link'and the corresponding piston, and -means 'for ladjusting each connection in each adjustment slot inY linear proportion between 'the adjustment land "the change insisten strekte-along annewnichmamtains Vthe Salfie Yall'lgllafr re'l'ti'fikvr'l" vvrtliA respetto the piston for any adj us'tniefntatat-fleas't one position -infthe stroke and' 'whichfat/c'crresponding positions maintains `the same angular relation with respect to each piston. l

4. In `a* constant deliveifyj pump,` a plurality of pumps each having a cylinderga-pistoninthe cylinder,v and jan inletjand outlet connection including check valves' to the cylinder,"therebeing a common uid'connectionlto'the inletsl'and a common nuid connection `to 'the outlets vof the cylinders, a link foreahpiston" movable inJa'p'ath which bears the .same angular rela'tion`to`each piston, pivotediockerssupporting eachlink at a plurality of spacedpoints,Wallsormingfanfadjustmentr slot ineaeh link. generally crossWise-vvith respect to the link}znetin,-cam-meanslfordriv ing the link soutjof-plia'se vvithfrespect to v-oneanother and with Vthe-'pumping Vstrokef'offone link displaced Withmrespect Vto the-pumping stroke of another link,-an adjustment support, adjustment rockers pivotal-ly g mounted v-on 'the radjustment support and at their outer ends each engaging in the adjustment slot of one of the links, means for moving the adjustment support in linear proportion to the change in piston stroke on a line which maintains the same angular relation with respect to each piston for any adjustment at at least one position inthe stroke and which at that position bears the same angular relation to all pistons, and means for interconnecting` each adjustment rocker and its piston while permitting adjustment of each rocker. I

5. In a constant delivery pump, a plurality of reciprocating piston pumps arranged with the pistons adjacent, parallel and facing in the same direction, common fluid inlet and discharge connections including check valvesA to the pumps, crossheads connected to the pistons and extending in prolongation thereof, guides for the crossheads for motion in the direction of the piston axes, a rocker parallelogram comprising two rockers and a link for each crosshead, the parallelogram rockers at each end having fixed pivots which are common for all parallelograms and are located transversely to the line of piston motion and at one side thereof, with pivotal interconnection between the parallelogram rockers and the link of each parallelogram, all rockers of the parallelograms being equal and parallel within each parallelogram and the rockers of all parallelograms being equal, adjustment rockers, one for each parallelogram, having a common pivot transverse to the lines of piston motion and at one side thereof, a sliding connection between each link at a point intermediate its pivotal connections with the parallelogram rockers and the end of one of the adjustment rockers remote from its pivot, a sliding connection between each crosshead and one of the adjustment rockers intermediate between its pivot and the sliding connection with the link, means for moving the adjustrnent rocker pivots toward and away from the crossheads in linear proportion to the change in piston stroke and means for moving the links back and forth in a position generally out of phase with one another.

6. In a constant delivery pump, a plurality of reciprocating pumps each having a piston and respectively adjacent with the pistons moving in parallel lines andfacing in the same direction generally out of phase with one another, common fluid inlet and discharge including check valves to the pumps, crossheads secured to the pistons and extending in prolongation thereof and in parallel relation to one another, guides for the crossheads on the lines of piston motion, a drive, a cam unit having cams pivoted for rotation on an axis transverse to the lines of motion of the pistons and at one side thereof and driven by the drive, the respective cams being secured in out-of-phase relation to one another, a rocker parallelogram adjoining each cam and including a pair of spaced equal parallel rockers on axes located to one side and transversely to the line of piston motion and a link making pivotal connection to the ends of the rockers and maintaining parallelism with the lines of piston motion, a follower for each cam interconnected with one of the links, an adjustment support, guides for moving the adjustment support transversely to the lines of piston motion from a position at one side thereof, an adjustment for moving the support along the guides, pivots on the adjustment support on a common axis transverse to the lines of motion of the pistons, equal adjustment rockers, one for each piston, pvoted one on each pivot, a sliding pivot connection between the swinging end of each adjustment rocker and one of the vparallelogram links extending transversely to the direction of motion of the links, and a sliding pivotal connection between each crosshead and Y oneA of lthe adjustment rockers extending Vlongitudinally of the rocker at a position on the crosshead which is the ls ame distance from each piston. Y l

7. In a constant delivery pump, a plurality of reciprocating pumps having pistons which are adjacent, parallel and face in the same direction, common vfluid inlet and outlet connections including checkfvalvesto the pumps, a crosshead extending in prolongationof each piston, guides for the crossheads permitting motion in the line of the pistons, sliding interconnections between the crossheads preventing rotation of each crosshead, a drive, a face cam unit having face cams secured to one another on opposite faces of the unit, respectively generally out of phase and mounted for rotation by the drive at an axis to one side of and transverse to the lines of motion of the pistons, a follower on each face cam, a rocker parallelogram for each piston including equal spaced parallel rockers pivcted transversely to the lines of the pistons and each at the same distance from its piston at either end of the stroke, and including a link connected with the follower of one of the face cams and making pivotal connection to the rockers at the ends, and adjustable means interconnecting each link with one of the crossheads adjustable in linear proportion to the change in piston stroke.

8. In a constant delivery pump, a plurality oi reciprocating pumps having pistons which are adjacent, parallel and face in the same direction, common fluid inlet and outlet connections including check valves to the pumps, a crosshead extending in prolongation of each piston, guides for the crossheads permitting motion in the line of the pistons, a drive, a face cam unit having face cams secured to one another on opposite faces of; the unit, respectively generally out of phase and mounted for rotation by the drive at an axis to one side of and transverse to the lines of motion of the pistons, a follower on each face cam, a rocker parallelogram for each piston including equal spaced parallel rocker arms pivoted transversely to the lines of the pistons and each at the same distance from its piston at either end of the stroke, and including a link connected with the follower of one of the face cams and making pivotal connection to the rockers at the ends, the rocker pivots at each end of all parallelograms being coaxial, an adjustment support positioned at one side of the crossheads, guides for the adjustment support permitting it to move transversely to the lines of piston motion toward and away from the crossheads, pivots on the support on a common pivot axis transverse to the lines of motion of the pistons and transverse to the line of motion of the support, equal adjustment rockers pivotally mounted one on each pivot, a sliding pivot connection of each adjustment rocker with one of the links extending transversely of the lilies of the piston motion, and a sliding pivot connection between each crosshead at the same distance from its piston and one of the adjustment rockers extending longitudinally of the adjustment rocker.

9. In a constant delivery pump, a plurality of pumps each having a cylinder, a piston in the cylinder, inlet and outlet connections to the cylinder, there being a common uid connection to the inlets and a common fluid connection to the Ioutlets of the cylinders, including check valves in the connections, cam followers, one for each pump, mechanical means for interconnecting each cam follower with one of the pistons, and cam means for driving the followers out of phase With respect to one another and with the pumping stroke of one piston displaced with respect to the pumping stroke of another piston, there being an overlap at the beginning and end of the respective pumping strokes of the pistons and there being a. cam correction for gradual acceleration and deceleration of the pistons added in the beginning of each pumping stroke andr subtracted at the end of each pumping stroke.

ROYALl BARTLETT SAALFRANK.

REFERENCES CITED The following referencesY areY of record inthe le of this patent:

UNITED STATES PATENTS Number Name Date Cowing Jan. 151856 Hale Jan. 5, 1864 McCarty Dec. 2,1, 1909 Persson Mar. 16, 1915 Herbsman May 23, 1933 Schutzniedrig Oct. 29, 1935 Rush Oct. 21, 1941 Sheen Nov. 18, 1941 Sheen Jan. 23, 1945