US1682570A - Pump - Google Patents

Description

Aug. 28, 1928. A 1,682,570

J. E. HOLVECK PUMP Filed June 28, 1926 2' Sheets-Sheet l FII-LZ.

FIELl.

Aug. 28, 1928.

J. E. HoLVEcK PUMP Filed June 28, 1926 2 Sheets-Sheet Kim @w s 4N Y rm.

am... i... v192;.

UNITED PATENT orifice.-

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f a'ppnmiaa mea mit as, laas. sem-1 110.418,90?.

This invention relates to pum s and more particularly to that type adapte to provide a variable delivery in accordance with 'variations in deman buti without any variation in the speed 'at which the pump 1s driven. .j

An object of this invention is to provide a pump unit of the type'set forthof'improved construction and having a simplified method of control.

A further object is to provide a constant speed, variable delivery pump which is slmp e and rugged in construction, reliable 1n operation andl relatively cheap to manufactureand assemble.

Theseand other oects which will be apparent to those skill in this. articular art are accomplished b meanso the present.

invention which is illustrated in the accom- 20 panying drawings,` wherein Figure 1 is a view in elevation of a pump unit constructed yin accordance with one form of this invention. Fig. 2 is a 'transverse sectional view on the line 2-2 of Fig. 1. Fi 3 is a simi.-

lar view on the line 3-3 of 1g. l1. Fig. 4-

is a sectonal view on the'line 4.-4 of Fi 3. Figs. 5 and 6 are diagrammatic views i ustrating certain details of operation hereinafter describedI and 7 1s a view similar to Fig. 2'show1ng the application of the invention to a different form of pump unit.

The particular embodiment of the resent invention which has been chosen for t e purf' poses .of illustration may be applied to a pump unit having any desired number of cylinders and includes se yarate t e axial positions ofw 'ch' are fixed rela tively to eachother. The crank shafts arev ders in such a way that a variation in thev relative timing of the crank shafts results inv a variation inthe delivery of the associated l ump unit. 1

ischarge valve 15 leading to a discharge oitlet 16.

The o rating mtcla-nism for-'each plung- 'lger is suc that the stroke of the plunger can be varied so as vary the delivery from'the Crank shafts,

lconnected by suitable connecting 'rods'with' nular llustra-ted, theinvention is applied to a triple cylinder pumpflO having the usual different pump chambers. As illustrated in Figs. 1y and 2', this mechanism includes a ,cross head 17 pivoted by a pin 18 to the upper end of each plu r.` One end of eaclno cross head is connecte Vto an associated crank shaft 19 by suitable connecting rods 20 and the other end of each cross head is connected to a crankshaft 21 by similar rods 22. Each crank shaftV is rotatabl mounted Ain station- 05 ary' bearings `so that t e axes of the shafts are fixed relatively to'each other. The vertical movements ofthe pump plungers are guided by a cradle 23 mounted .between up-` riffhts 24 upon which the crank shaftbear- 7 in's may conveniently be mounted.

Any convenient source of power such for example, as a motor 25 can be used to riveA .the pump. As illustrated, the motor armature is connected to a drive shaft 26 having 75 a gear 27 meshing with a driving gear 28 on the crank shaft 21. The two crank shafts are geared together forruntary movement d the gearing connectin them is of such construction that the relative ftiming of the two shafts may be varied so as to vary the stroke ofthe associated plungers. [As illustrated, this earing includes aspur .gear .29 secured to the crank shaft 21 andmeshing with the external teeth of an annular rotatably mounted upon the associat shaft 19. An arm 31 is 'rotatably mounted upon the crank shaft L9 and atpone end is j provided with a stub shaft 32 pinned to the arm and pro'ecting into the hollow annulai ao gear 30. .A pur gear 33 isrotatably mounted upon the projecting end of the stub shaft and meshes with the internal teeth of the annular gear 30 on one side and a spur gear 3ft keyed to the' shaft' 19 within the-annular 95v gear 30.0n the other side. *The opposite end of the arm 31 has a stub shaft 35 rotatably mounted therein 'and extending into the anar on' the opposite side of the crank shaft rom the planetary gear 33.` A secondplanetary gear 3.6 is fkeyed to the `stub shaft 35 andmeshes with the internal vteeth of the annular gear-30 on one side and with the spur gear ke ed to the crank shaft o n the other side. crankarm 37 is secured 105 to vthe lop osite end of the stub shaft 35 and connecte to a rod 38 for a urpose to be a hereinafter described. The p anetary gear supporting arm .31 has a flange or extension 39 connected by connecting rod 4 0 with a 110 plunger 41 received within a cylinder 42, the. lower end of which is connected by a ar 30 85 I crank V suitable adjustment lill pipe 43 with the discharge manifold of the pump so that the piston 4l is affected by any variation in the pressure of the pump discharge. A .coil spring 44 is provided between'a cross head 45 secured to the plunger 4l and a stationary cross head 46 mounted upon rods 47 extending upwardly from supports 48 secured to the cylinder 42, see Fig. 3. Obviously, an 'increase in the discharge pressure will elevate the planetary gear shifting piston 41 against the pressure of the spring 44 so as to shift the planetary gear supporting arm 31, while any decrease in the discharge pressure of the pump permits the spring 44 to force the piston 4l downwardly. The lowermost limit of the con-A necting rod 40 and piston 41 may be set by of a nut 49 threaded to the connecting rod and adapted to engage the upper stationary cross head 46.

It will be apparent that when the crank shafts are so timed that the cranks a, b and c of the shaft 2l, see Fig. G, are in time with the cooperating cranks a', y and e, respectively, of the associated shaft 19 the stroke of the pump plungers 12 will be at a maxi mum and the pump delivery willv also be at a maximum. This occurs when the gear shifting piston 4l is in its lowest position. Any upward movement of this piston and corresponding shifting of the planetary gears 33 and 36 will vary the timing of the two crank shafts as such a movement of the planetar gears causes a shifting of the relative positions of the ears 29 and 34 keyed to the respective sha ts. This in turn causes a corresponding shifting in the-timing of each pair'of cooperating cranks a and m etc., and a resulting decrease in the plunger travel so as to reduce the pump delivery. The gears forming the lanetary gear train are kso formed and o such relative sizes that the vtwo crank shafts will revolve at the same speed when the planetary gear shifting arm 39 is stationary. The proportioning of the gears forminor the gear train is such that a movement of of the gear supporting arm 39 will rotate the gear 34, and consequently the crank shaft 19, 180 with respect to the assaociatcd crank shaft 21. If the respective y crank shafts are in the' position'diagrammatically illustrated in Fig. 6, wherein each two associated cranks connected to the same piston rise and fall together, the delivery of the pump unit will be at a maximum, as above pointed out. If, now, the demand to be satiied by the pump discharge falls the pressure built up in the discharge line will elevate 4the planetary gear shifting piston 41 so as to shift the planetary gears and change the relative timing of the associated crank shafts. If the demand drops suiiiciently to shift the gear supporting arm 45 the crank shafts will assume the relative .is shifted to the left as positions indicated in Fig. 5, wherein each associated crank moves in opposition to the other associated crank. The result is that as one connecting rod 20 rises the other connecting rod 22 falls and there will be no appreciable'movement of the associated plunger 12. Under these circumstances the pump discharge is at a minimum.

' As a. matter of actual practice it is impossible to obtain zero delivery by the above described mechanism, due to the angularity assumed by the connecting rods 2O and 22. In order to obtain zero delivery without stopping the pump an arrangement for unloading the pump suction valves is associated with and adapted to be operated by the mechanism for varying the timing of the crank shafts.

The connecting rod 38, heretofore referred to, is continually reciprocated by the crank arm 37 and the lower end of the connecting rod is provided with a rack 5U in mesh with and adapted to oscillate a gear 5l loosely mounted upon a hollow shaft 52. The oscillating gear has a beveled tooth 53 projecting outwardly on each side thereof, sec Fig. l. The hollow gear supporting shaft 52 is provided with diametrically opposed slots 54 and a rod 55 extends into one end of the hollow shaft and is provided with a pin 56 extending outwardly on one side of the hollow shaft through one of the slots 54 on one side of the oscillatory gear 5l, and a second pin 57 extending through the other of the slots 54 on the opposite side of the oscillatory gear. The rod is slid- -able longitudinally of the hollow shaft so that either one or the other of the projecting pins 56 and 57 can be shifted to engagement with an associated tooth 53. 'lhe outer end of the slidable rotatable rod 55 is connected to the core 58 of a solenoid 59 and is normally spring pressed outwardly by a spring 6 so as to position the pin 56 in the path of the adjacent gear tooth 53. When the solenoid is energized by closing its circuit through a switch 61 the rod 55 seen in Fig. 1 and the pin 57 is moved into engagement with the associated gear tooth 53 while the pin 56 is moved out of engagement with the adjacent gear tooth. The end of the hollow shaft opposite the solenoid is connected to a rotatable shaft 62 having cams 63 secured thereto beneath each of the suction valve stems 14. It will be apparent that when the cam shaft 62 and cams 63 are in the position illustrated in Fig. 2 the pump will be loaded, but that a movement of of the cam shaft will cause the suction valve stems 14 to be elevated by the high parts of the associated cams so that the suction valves will be held away from their seats and the pump cylinders unloaded. The unloading cams are so positioned upon the supporting shaft 62 that the pump will be unloaded and the delivery reduced to zero when the solenoid 59isde-energized. This permits the spring 60 to expand and move the rod pin 56 into the path of the oscillating gear toothf53 as shown. The oscillating gear 51 and -gear tooth 53 oscillate lthrough an arc of 1`80 so'athat the 180 movement of the hollo\w shaft 52 and cams I 63 causes'tlie suction valves of the pump to be unloaded.4 B energizing the solenoid the pin 56 is move away from the oscillator gear and the pin 57 is moved into the at ofthe adjacent gear tooth 53 upon its si e of .the oscillatory gear. It is apparent that this causes the cam shaft62 and cams 63 to Abe rotated `another 180, resulting in the low parts of the cams being positioned opposite v the' suction' valves so that the latter vare rmitted to close. and the pump is loa ed. The beveling of the teeth 53, see Fig.' 1, prevents .the pins 56 and .57 from beingvv moved except in the desired direction. Back# and resulting in such a movement of the unloading cam 63 .as willunload the pump. When the demand is again in evidence the downward movement of the cross head will cause the switch 64 to close the solenoid circuit and again load the pump. The

manually operable switch 61is, of course,

ward rotationv of the unloading-cams is im-A possible.

Advantage .is taken of this form of operation (for automatically unloading the pump when the demand drops to zero and automatically loading again when there is a further demand. As illustrated, this a'uto- Y matic control consists of a 'switch 64 posii tionedin the solenoid circuit, see Fig. 1, and

adapted to be normally closed. The switch is provided with an operating handlel or projection 65 which extends into the path of movement of the slidable cross head 45 movable with. the planetary Gear operating piston. As heretofore pointe out, when the vdemand for the pump discharge drops the discharge pressure will be increased so that the planetary gear shiftingpluner 41 and pressure of the spring 44. As t pointed out, 'this upward movement ca cross head 45 are moved upwar ly against normally closed during operation ofthe ump. A

It will be'apparent that the crankarm 37 rotates simultaneously with, and at the.

same speed as the pump crank shafts. The `1 cams 63 are rotated by anvupward movement of the crank arm 3 7 and the latter is so timed that each cylinder will loadonly at thebeginningof a discharge stroke.

This is tosay, thev cams 63 `will'be *rotated only during the suction strokes of the vari- /ous cylinders. This prevents the pump loading with a sudden jar and-'causes a gradual increase in torque -from zero to maximum instead of asudden jarring in.

.crease'to maximum torque result-ing in exf the timing ofthe two crank shafts will vary the tlming ofthe strokes of the separate such a rotation of the planetary gearing as to change the timing of the respective l crank shafts in such a manner as to .reduce the amount of fiuiddelivered by the ump. Even when the crank'shafts are tim 180 apart, however, it is impossible to obtain absolute zero delivery by. such a construction, due to the relative angularity (if the `various connecting-rods. That is to say,4that even with the cranks a. andv :v positioned as shown-in Fig. 5 there would be some movement given to the plunger 12. The automeans of obtainiugzero delivery. If there isv no demand 4whatever for pump `delivery the cross head 45 will continue to `move upwardly as long as vthere is an discharge from the pump and this upwar movement .will linally cause the cross head to engage the switchv 64 and break the solenoid circuit, permitting the spring 66 to expand plungers 72 in such'a way as to cause a corres onding variationin the ump'delivery.

- lthough I have describedp a specific embodiment of-this invention it will be apparent that various changes, additions, modifications and substitutions can-be made thereinfwithout departing from the spirit of theV invention or the scope of theappended claims.

What Iclaim as new and desire' securef `by Letters'Patent is 1. A variable' deliverypump having in combination parallel operating shafts rotatably mounted in fixed relation and means for varying \the relative timing of said shafts.

2. A-variable delivery pumphaving in' combination parallel crank shafts. mounted p jin fixed relation toeach other' and means matic switch 64, however, provides' a simple for changing the relativetiming ofsaid shafts for varyingythe `delivery of said' pump.

3. The combination in va pump .otwof parallel fixed crank' shafts and means for-` vrying Athe timing of said shafts during operation'of the pump so as to vary the delivery of lsaid pump without Changingjhe speed thereof. s f t ico 4. The combination in a variable delivery pump of two parallel crank shafts mounted in fixed relation, gears connecting said crank shafts for simultaneous operation, means for drivingr said crank shafts and means for varying the relation of said gears so as to change the timing of said crank shafts and vary the delivery of said pump.

5. The combination in a variable delivery pump of two parallel crank shafts mounted in fixed relation, a planetary gear train connecting said shafts for simultaneous rotation, means for driving said shafts and means for so controlling said planetary gear train as to vary the timing of said crank shafts so as to vary the delivery of said pump.

6. The combination in a variable delivery pump of parallel crank shafts mounted in fixed relation, a planetary gear train connecting said crank shafts for simultaneous rotation, means for driving said shafts and means subject to the discharge pressure of the pump for so controlling said gear train as to vary the timing of said crank shafts and vary the delivery of said pump in accordance with changes in the discharge pressure thereof.

7. The combination in a variable deliver)1 pump of a pair of crank shafts adapted to be simultaneously rotated, plunger mechanism operated by said crank shafts, means for simultaneously rotating said crank shafts including an annular gear connected to one of said shafts by intermediate planetary gears and means for shifting said planetary gears relatively to said annular gear so as to vary the relative timing of said crank shaft.

8. The combination in a variable delivery pump of crank shafts mounted in fixed rela.- tion, a gearon each of said shafts for simultaneously rotating said shafts, an annular gear' supported upon one of said shafts and meshing with the gear on the other'of said shafts, planetary gearing connecting said annular gear with the other of said shafts and means for shifting said gearing so as to vary the relative timing of said shafts.

9. The combination in a variable delivery pump of separate crank shafts, plunger mechanism operatively associated therewith, means for controlling the timing' of said shafts so as to vary the delivery of said pump, means for loading and unloading said pump and a movable member responslve to the variations in the pressure of the pump discharge for automatically controlling the operation of said loading and unloading means. A

10. The combination in a variable delivery pump of separate crank shafts, plunger mechanism operatively associated therewith, means for varying the timing of said shafts so as to vary the pump delivery, mechanism including a solenoid for loading and unloading said pump, a switch in the solenoid circuit and a movable member adapted to be shifted in accordance with variations in the pressure of the pump discharge for operatingfsaid switch so as to control said loading and unloading mechanism.

11. The combination in a variable delivery pump of separate crank shafts mounted in fixed relation, gearing connecting said crank shafts for simultaneous rotation, mechanism for loading and unloadin said pump, means for operating said mec ianism from said gearing, a solenoid for controlling the operation of said mechanism. a switch in the solenoid circuit and a movable member adapted to be shifted in accordance with variations in the pressure of the pump discharge for operating said switch so as to permit said pump to load and unload.

12. A variable delivery pump having iu combination parallel operating shafts rotatably mounted in fixed relation and means responsive to variations in the discharge pressure of the pump for varying the relative timing of said shafts.

13. The combination in a pump of two parallel crank shafts rotatably mounted in fixed relation and means responsive to variations in the discharge pressure of the pump for varying the timing of'said shafts during operation of the pump so as to vary the delivery of said pump without changing the speed thereof.

14. The combination in a variable delivery pum of two parallel crank shafts mounted in xed relation, gears connecting said shafts for simultaneous operation, means for driving said crank shafts and means responsive to variations in the discharge pressure of the pump for varying the relation of said gears to change the timing of said crank shafts and va the delivery of said pump.

15. The com ination in a variable delivery pump of separate crank shafts, gearing con necting said shafts for simultaneous rotation, mechanismfor loading and unloadin said pump and means for operating sai mechanism from said gearing.

16. The combination in a variable delivery pump of separate crank shafts, plunger mechanism operatively associated therewith, means for controlling the timing of said shafts so as to vary the delivery of said pump, means for loading and unloading said pump, and mechanism res onsive to the variations in the pressure of t e pump discharge vfor synchronizing the operation of said loading and unloading means with the operation of said plunger mechanism.

In testimony whereof, I have hereunto subscribed my name this 11th day of June, 1926.

JOSEPH E. HoLvEoK.

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