US2634683A - Pump and stroke adjusting mechanism - Google Patents

Description

Ap 14, 1953 H. J. ANDERSON PUMP AND STROKE ADJUSTING MECHANISM 3 Sheets-Sheet 1 Filed Aug. 16, 1946 m R 5 o o T. M u! N EH m m M V I M m n I v A i A J a "J an r INN. NQ Q a8 a wl w. 2, PG mNN N 3 N m NM 2 E a: mu N3 mm a QR MN $4 Mn N m3 3 MN R4 mm mm J WWN. N WNN- a 1 98 we w w lll\\ Nu n MR unmm mmnu H an NJ 1? ,A/ .n m .II o .3 n T". \QQN mg 2 2w mm Wis g 55: .rli 28 w H N .3 3 mw Qt N a B1 81 S April 14, 1953 H. J. ANDERSON PUMP AND STROKE ADJUSTING MECHANISM 3 Sheets-Sheet 2 Filed Aug. 16, 1946 INVENTOR.

Hgrry JAnderson mu mm mm April 14, 1953 J. ANDERSON PUMP AND STROKE ADJUSTING MECHANISM 3 Sheets-Sheet 3 Filed Aug. 16, 1946 INVENTOR. rry Jflndensan BY 3 fix Patented Apr. 14, 1953 PUMP AND STROKE ADJUSTING MECHANISM Harry J. Anderson, Chicago, Ill., assignor to Hills- McCanna Company, Chicago,

of Illinois Application August 16, 1946, Serial Claims. 1

This application is a continuation-in-part of application Serial No. 576,180 (now Patent No. 2,458,821), filed February 5, 1945, entitled Pump and Stroke Adjusting Mechanism.

In application Serial No. 576,180, there is disclosed and claimed a novel displacement pump, a hydraulic stroke control device. The present invention is directed to improvements in various features of the stroke control device shown and described in the aforesaid application.

An object of the invention is to provide a novel pump and stroke control device.

Another object of the invention is to provide a novel hydraulic stroke control device for displacement pumps.

Still another object of the invention is to provide improved valve mechanism for a stroke control device of the type shown and described in application Serial No. 576,180, now Patent No. 2,458,821.

A further object of the invention is to provide means for facilitating opening of the outlet valve of a hydraulic stroke control device of the type shown and described in application Serial No. 576,180.

A still further object of the invention is to avoid inaccuracy of hydraulic stroke control mechanism caused by gas or vapor accumulation in the control mechanism.

Another object of the invention is to provide an improved coupling for fastening the piston of the pump to the piston or plunger of the stroke control device.

Other objects of the invention will be evident from the following description and accompanying drawing of whic Figure 1 is a fragmentary side elevational view partly in cross-section of a stroke-control device and pump embodying the invention;

Figure 2 is a plan view with certain parts broken away and others removed showing the complete stroke-control device shown in Figure 1, but on a smaller scale;

Figure 3 is an enlarged perspective view looking downward from the left hand side, of a disc or slide element forming part of the valves of the stroke-control device;

Figure 4 is an enlarged front elevational view partly in section of a coupling connecting the pump piston to the stroke control plunger; and

Figure 5 is an enlarged side elevational view of the coupling shown in Figure 4.

Referring to the drawings and more particularly to Figures 1 and 2, the numeral I represents a casing in which all the moving parts of 111., a corporation races.

the stroke adjusting device are housed with the exception of a portion of the crankshaft 3 which extends beyond the side of the casing in order that it may be connected to a suitable source of power cap-able of imparting thereto rotary motion at the desired speed. The casing is provided with four flanges 5, one extending horizontally from each corner at the bottom of the casing, provided with holes I so that the casing may be bolted firmly to a suitable foundation. The casing may also be provided with a screw drain plug (not shown) at the bottom of the left end in order to drain liquid from the casing,

The crankshaft 3 is keyed to crank 9 by means of a key ll. Crank 9 is rotatably supported in one side of the casing by ball bearings l3 held in place between inner bearing race l5 and outer race ll. The outer race I1 is press-fitted snugly into a circular opening in the side wall of the casing. A crank pin I9 is screwed in the crank 9 eccentric to the crank shaft 3. The end 20 of the pin extends between spaced walls 2i of a cross-head 23. The end 20 is mounted on roller bearings held in place by inner and outer bearing- The outer race fits snugly between walls 2| and is adapted to slide up and down therebetween. The construction of the cross-head and manner in which the crank pin fits between the spaced walls thereof is shown and disclosed in detail in application Serial No. 576,180 now Patent No. 2,458,821. The crank shaft through the crank and crank pin imparts reciprocating motion along a straight line to the cross-head.

The outer end of the crank is provided with a split ring clamp 25 made of spring steel which fits in a recess in the periphery of the crank and prevents inward movement of the crank. It is apparent that the crank cannot move outwardly because of the abutment of the face 21 against the inner face of the outer bearing race.

The cross-head 23 is integrally formed with two opposite, horizontally extending cylinders 23. In View of the fact that the left side half of the device is a mirror image of the right half when the device is equipped for dual operation, only the right half of the device is shown in detail in Figure 2. The end of each cylinder connected to the cross-head is closed. The free end 31 of the cylinder is open and adapted to be supported and slide in the cylindrical bearing 33 which fits in an opening in the end wall of the casing and is fastened thereto by studs 35 and nuts 31. The bearing 33 is an integral part of a sump 39 fastended to the end of easing l and sump 39 is provided with passageways 4| to permit breathis sloped or bevelled at 69 3 ing and ingress and egress of oil to and from the space 42. The sump may be provided with a drain plug at the bottom thereof.

Referring to Figure 1, cylinder 29, adjacent,

the juncture with the cross-head has two diametrically opposite bores 43 and 45 tapped therethrough to accommodate inlet and outlet valves indicated generally by the numerals 41 and 49. Bore 43 is provided with screw threads to permit the valve body having an axial passageway 53 to be screwed therein. The outer end of the body 5| is serrated as shown at 55 in order to provide openings for passage of fluid when the slide element 5'! is in open position. The element 57 is adapted to fit snugly and slide in seat 59 which in turn is press-fitted into cap 6| which is screwed onto the outer end of body 5|.

Referring more particularly to Figure 3, the construction of slide element 5'! is more clearly shown. The element 57 is a solid cylinder with two elongated slots 63 milled through from one side to the opposite side of the periphery, at right angles to each other. One end 65 of the element 51 (the upper end in valve 5| and the lower end as to one element and the upper end as to the other slide element in valve 49) is solid and of somewhat greatercircumference than the main portion 57 of the element. The surface of end 55 where it joins the main portion 61 in order to provide better contact between the element 51 and the valve seat when in closed position. The slots 53 run from the bevelled edge to the other end of the element.

It will be apparent that on the suction stroke of the pump, if the cylinder 29 is not full of liquid, the element 57 of valve ll will be lifted against the serrated end 55 of the body 5I permitting liquid to enter the valve through the open end of the element 51 and then pass through slots 63 into space ii and then through passageway 5I into cylinder 29;

Outlet valve 49 is held in place at the top of cylinder 29 by means of bolts 13 (Figure 2) which screw into threaded holes tapped in the top of the cylinder wall. Valve 49 comprises a main body portion 75 with upper and lower valve seats 'Il' and 19, respectively, in each of which a slide element 51 is adapted to be seated. It is apparent from the drawing that the lower slide elementis seated in. the same manner as described in connection with the outlet valve 47 but the upper slide element is seated upside down. A coil spring 8| is held in place between the two slide elements of valve 49 and normally keeps the elements in closed position. A bleeder passageway 83 of very small diameter is formed in the seat 79 to provide open communication be tween cylinder 29 and space 85.

A laterally extending arm 81 is formed integrally with the body portion I5 of valve 49. The end of another arm 89 is pivotally mounted at 9| between the bifurcated end of stationary arm 87.. The free end 93 of arm 89 is directly over valve 49. The free end 93 has a threaded passageway adapted to receive bolt 55. As shown, the head of the bolt is adapted to rest on the bottom 65 of upper slide element 51. A nut 87! is placed on the upper end of bolt 95 to lock it in position. A roller 99 is mounted intermediate the ends of arm 89 with the upper edge of the roller extending above the upper edge of the arm.

Still referring to Figure l, the opposite end walls of the casing adjacent the top center thereof are provided with opposite horizontal bores I 5| to accommodate a rod N13. The rod I03 is directly over the axis of cylinder 29 and directly over valve 39. Rod I03 is held in place by set screws m4. A bracket I95 is rigidly mounted on rod I93 by set screw I06 exactly in the middle thereof. A roller I 9'! adapted to rotate on a vertical axis is mounted onthe bottom of bracket I 95. The ball-bearing mounted roller rotates 0n the spindle I98 which is screwed into a threaded hole tapped in the bottom of the bracket. The roller Hi7 fits in a lengthwise slot I99 (Figure 2) on the top side of the crosshead and prevents the crosshead from turning from its vertical position. The slot is of slightly greater width than the diameter of the roller.

The bracket I65 is provided with a horizontal bore I I adapted to receive one end of a threaded stein Ii 3. The stem extends through a horizontal bore I I5 in the end casing wall directly below rod I03. The other end iii of the stem is knurled in order to .enable it to be turnedby hand. A'collar |I9 containing a set screw I2| is placed on the stem abutting the inside wall of the casing. By virtue of the fact that the inner endof the threaded portion of stem H3 abuts the bracket I65 and the collar abuts the casing wall, the stem will not move horizontally when turned. A set screw I22 is provided at the top of the casing to prevent the stem I I3 from turning. The screw is provided with an enlarged head to permit it to be turned by hand.

An elongated threaded cam E23, preferably of cylindrical shape, is mounted on the stem. The right edge I25 of the cam is bevelled to provide smooth contact with roller 99. The length of the cam is such that when in the left-most position it will not be contacted by roller 99 and is at least as long as the stroke of the pump. Upon contact between the cam and roller 99, arm 89 is depressed, in turn depressing the upper slide element 5'? of valve 49, thereby opening the valve and allowing liquid to escape from cylinder 29. During the discharge stroke the spring 5! does not exert enough force to keep the lower slide element 57 of valve 49 in closed position. The lower slide element acts asa check valve to close a the outlet valve during the suction stroke.

Cylinder 29 is provided at the side thereof with a safety or relief valve I2! (Figure 2) which is loaded to remain closed until a predetermined pressure exceeding desired maximum operating pressure is reached. The valve is adjustable and may be set for different pressures by turning screw |29.

As shown in Figure 1, casing I is provided with a removable cover |3I which is held in place by screws I53. Sump 39 is also provided with a removable cover I34. Figure 2 has been shown with the covers removed in order to expose the elements inside the casing for observation. I

Returning to cylinder 29, a plunger I35 is mounted therein. One' end l3? of the plunger fits snugly in the cylinder and is equipped with suitable rings to prevent leakage of fluid from one side to the other of the end I37. The outer end of cylinder 29 has an annular ring |39 fastened thereto by means of screw MI. The opening in ring I39 is of smaller diameter than that of the end I51 of the plunger, but of larger diameter than that of the remainder of the plunger. The ring I39 prevents the plunger from slipping out of cylinder 29. h

The plunger I35. is supported and adapted to slide in a bushing I53 rigidly mounted inan open- .ing in sump 3 9, suitablering seals I IS are placed in recesses in the bushing I43 to preventleakage.

An annular recess I41, connected to a passageway 290 is provided in the sump wall between ring seals I45 to permit oil to escape therefrom and thereby indicate if the seals are leaking.

The plunger I35 is formed with an annular recess I49 a short distance from the end I5I. The end I5I of plunger I35 is fastened to the end I53 of pump piston I55 by means of a split ring coupling I51. The end of pump piston I55 is formed with an annular recess I59 similar to recess I49.

Split ring coupling I51 is more clearly shown in Figures 4 and 5. It is formed of two semicircular rings IBI. Each half of the ring has a semi-circular portion I63 removed concentric with the outer circumference of the half-ring. Each half-ring also has a semi-annular recess I65 in the inner surface intermediate the side edges of the ring and of sufficient width to accommodate the end I5I of the plunger I35 and the end I53 of piston I55. The removed portions I93 are of sufficient radius to accommodate the recessed portions I49 and I59 of the plunger and pump but of lesser radius than that of the ends I5! and I53 of the plunger and pump. The two halves of the coupling each have a semi-annular recess I31 around the outer circumference. The two halves of the coupling are held together by a split ring clamp I99 made of spring steel adapted to fit in the recesses I61. The combined opening formed by removed portion IE3 is slightly greater in circumference than the recesses I49 and I59 of the plunger and piston, and the combined re cesses I95 are slightly greater in circumference than the ends I5I and I53 of the plunger and pump, thereby permitting a small amount of free play and avoiding strain which might otherwise be caused by imperfect alignment of plunger and piston.

The piston I55 fits snugly and slides in a pump cylinder (not shown) located in a pump housing I1I shown fragmentarily, corresponding substantially to that shown in application Serial No. 576,180. The pump housing I1I is fastened to the end of sump 39 by means of studs I13 and bolts I15. The pump housing may be a hollow jacket formed with a cylinder to provide means for circulating cooling liquid therethrough around the pump cylinder.

Located in sump 39 is a gland I11 mounted at the end of the pump cylinder and held in place by means of studs I19 and nuts IBI.

The stroke control device shown in the drawings is intended for single operation and therefore the valve, valve control mechanism, plunger, sump and pump have been omitted from the left-hand side. Instead, the left end of the casing I is closed by a closure I83 (Figure 2) fastened to the end of the end of the casing by means of studs I85 and nuts I81. The closure is formed with a cylindrical bearing corresponding to bearing 33 in order to support the left cylinder 29.

If it is desired to operate the device as a dual unit, the closure I83 is replaced with a sump corresponding to sump 39 and the other necessary elements such as plunger, valves, valve control mechanism, piston and pump housing.

The operation of the device is as follows:

Assuming cam I23 is in its left-most position, it will not engage roller 99 during any portion of the pump stroke. In such case the pump operates at full stroke because during the suction stroke oil or other liquid is sucked into cylinder 29 through valve 41 and the cylinder becomes filled. During discharge stroke spring 8| plus oil pressure in cylinder 29 keeps the upper slide element 51 of valve 49 in closed position and likewise, internal pressure will keep valve 41 in closed position. At the end of the suction stroke the cylinder 29 and plunger I35 will be in the position shown in Figure 1 Since there is no place through which liquid in cylinder 29 can escape the plunger I35 and hence piston I55 will be reciprocated through the full or maximum stroke imparted by the crank and driving mechanism.

Assume now that his desired to operate the pump on partial stroke. The stem II1 will be turned until the cam I23 is located intermediate its left-most and right-most positions as, for example, the position shown in Figure 1. At the end of the pump discharge stroke roller 99 will be in the position shown in dotted lines on Figure 1 and the upper slide element 51 of valve 49 will be closed. As the cross-head moved left-ward on the suction stroke, suction will be created in cylinder 29 and oil or other liquid will be sucked into cylinder 29 from casing I through valve 41. When roller 99 strikes the bevelled edge I25 of cam I23, the arm 89 is depressed, in turn depressing the upper slide element 51 of valve 49 and causing it to open and remain open as long as roller 99 is in contact with cam I23. However, the lower slide element 51 of valve 49 remains closed during the entire discharge stroke, thereby preventing egress of air through valve 49 into cylinder 29 during the suction stroke except for the small amount that enters through bleeder 33.

Upon the start of the discharge stroke valve 41 closes and the lower slide element of valve 49 opens because as previously explained, the load on spring 8| is not suificient to keep the lower slide element closed against the fluid pressure in cylinder 29 during discharge stroke. Since the upper slide element 51 is also in open position, because depressed by arm 89 liquid as well as any gas or vapor which may have accumulated in the cylinder will escape from cylinder 29 through valve 49 until roller 99 rides free of cam I23. Because the liquid can escape from cylinder 29 through valve 49, there is not suificient hydraulic pressure to cause plunger I35 to move and hence, although cylinder 29 moves forward, plunger I35 remains stationary until valve 49 closes at which time the remaining liquid trapped in cylinder 29 forces the plunger and pump piston to move through the remainder of the cylinder stroke. On the return of suction stroke the cylinder will move backward until the end I31 of the plunger abuts the ring I39 and then pulls the plunger back to the beginning of its discharge stroke.

It will be noted that to obtain a shortened pump stroke liquid is discharged from the cylinder 29 during the early part of the discharge stroke rather than during the latter part of the stroke. By regulating the stroke in this man- .ner, accuracy of stroke is obtained due to the fact that any gas, such as air, or vapor which may be trapped in the cylinder is expelled during the non-operating portion of the cylinder stroke and, therefore, does not form a compressible cushion in the cylinder during the delivery or operating portion of the stroke. By placing valve 49 at the top of the cylinder 29 gas and vapor is readily expelled.

Another feature of the device which constitutes an improvement over the device shown and described in application Serial No. 576,180 now Pat- 'ent No. 2,458,821 is the bleeder passageway 83 in valve 49. g This passageway may be extremely small of the order of 1% diameter. Its purpose is to relieve pressure in valve 419 between theupper and lower slide elements 51 so that the upper slide element 51 can be opened at anypoint in the stroke of the pump without exerting undue pres- .sure on the element. Without the 'bleeder -83 liquid becomes trapped between the two closed slide elements during suctionstroke and makes it diiicult if not impossible to depress the upper slide element.

It will be evident that the farther the 'cam- 123 is moved to the right the shorter will be the pump stroke. The stroke can be varied from substantially zero to full stroke.

Although the stroke adjusting device has been described in connection with a piston type pump,

it is adapted for use with other displacement type pumps as for example diaphragm pumps and in general for operating any variable stroke mechanism.

In operation the casing is preferably filled with oil to the top of the crosshead so that th entire moving mechanism operates in an oil bath, although it is necessary only to maintain the oil bath above the inlet valve 57. Likewise, the sump 39 is preferably maintained filled with oil above the moving parts.

It will be apparent that if the device is operated as a dual unit, one side will b operating on suction while the other is operatin on the discharge stroke. Two different liquids can-be pumped at the same time and the rate of delivery of each liquid can be independently cont-rolled so that desired proportions of the two liquids can be delivered to any desired point.

Although the stem H3 has been described as 7 being operated by hand, on large size units, provision can be made to have the stem operated by motor.

It is claimed:

1. A stroke adjusting mechanism comprising, a reciprocable cylinder having an open end and a closed end, means for imparting reciprocating motion to said cylinder, means for admitting liquid to said cylinder, a plunger mounted in said cylinder and extending from one end thereor", the extendin end of said plunger bei adapted to be connected to a load, a normally closed valve adjacent 'the'closed end of "said cy inder, said valve "having a passagewa therethrough, two spaced valve seats and two Sprin actuated valve elements cooperating with said seats to close saidpassageway, said elements being actuated to closed position by movement in directions away-from each other, .a second unobstructed passageway of small cross-sectional area as compared to said first mentioned passageway, connecting the space between said valve seats with said cylinder, and means for holding said valve in open position during the earlypart of the discharge stroke of said cylinder andpermitting said valve to-close during the latter portion of said dischargestroke.

2. A stroke adjusting mechanism comprising a reciprocable horizontally disposed cylinder open at one end and closed at the other, a valve for admitting liquid to and preventing escape of liquid from said cylinder, means 'for imparting reciprocating motion'to said cylinder, a plunger extending fromthe openend of said cylinder and adapted ,tobe'IQad'e'd a normally closed valve at the top, of said'cylinder adiacent'the closed end thereof, said valve having a"passageway*thereable said element through, two spaced valve seats and two sprint actuated valve elements cooperatin with said seats to close said passageway, said elements being actuated to closed position by movement in directions away from each other, a second unobstructed passageway of small cross-sectional area as compared to said first mentioned passageway, connecting the space between said valve seats with said cylinder, and means for holding said valve in open position during the early portion of the discharge stroke of said cylinder and permitting said valve to close durin the latter part of said stroke.

'3. A stroke adjusting mechanism in accordance with claim 2 in which the means for holding said valve in open position is adjustable to enable the valve to be held in open position during any portion of the stroke of said cylinder.

4. In combination a cylinder having a plunger mounted therein, means for drawing fiuid into and discharging fluid from said cylinder, said means for discharging fluid comprising a, valve chamber, two spaced slide elements adapted to close said chamber, means for normally holding said slide elements in closed position, means .for depressing on of said slide elements from its seat to permit fluid to be discharged from said cylinder and a small unobstructed passageway connecting the interior of said cylinder and said valve chamber.

5. The combination in accordance with claim 4 in which one slide element is adjacent the cylinder and adapted to remain closed while fluid is drawn into said cylinder and is placed "between the cylinder and the slide element adapted to be depressed.

6. A valve assembly comprising a body having a passageway therethrough and having at least two spaced apart valve seats, valve elements said body adapted to coactwith said valve seats to close said passageway, said elements being adapted to close in oppositedirections away from each other, means for normally holding said elements in closed position, and a b-leeder passa through said assembly connecting th space in said assembly between said valve seats with the exterior of said body at a point adjacent said passageway.

7 A valve assembly comprising a valve body having a, passageway 'therethrough and having spaced oppositely disposed valve seats, two slide elements in said body adapted to coactwith said seats to close said passageway when said ele- "ments move indirections away from eachother,

means coacting with one of said elements to ento be moved from its seat, a sprin for normall holding said elements in closed position and a bleeder passageway adjacent one of said slide elements connecting the space between saidslide elements to the space outside said valve'body at a point adjacent said first mentioned passageway.

8. A valveassembly in accordanc with claim '7 including a stationary arm extending from the outside of said body and a movable arm, pivotally mounted on said stationary arm, adapted to engage theslide element remotefrom saidbleeder in such manner as toenable said element -to be depressed from its seat when to said pivotally mounted arm.

9. A stroke adjusting mechanism in accordpressure is applied ance withclaim 1 in which "the meansifor hold- "ing said valve in open position comprises apivotally mounted arm adaptedto reciprocate -with said cylinder, and adjustable stationar cam adapted to contact and depress said arm into contact with said valve.

10. A variable stroke device comprising a reciprocable cylinder closed at one end, a plunger adapted to reciprocate in said cylinder, means for connecting said plunger, through the open end of said cylinder, to a load, means for admitting liquid to and discharging liquid from the cylinder space between the closed end thereof and said plunger, means for effecting discharg of liquid as well as any gas or vapor accumulated in said space, during the initial part of the discharge stroke of the cylinder, means for preventing escape of fluid from said space during the latter part of the discharge stroke thereof and means for effecting intake of liquid into said space during the suction stroke of said cylinder. HARRY J. ANDERSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Hearn Jan} 10,1888 Muller Aug. 8,1899 Davis Oct. 6, 1907 Zinke Apr. 20, 1909 Aikman June 21, 1938 Anderson et a1. Jan. 11, 1949

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