US2430764A - Pump - Google Patents

Description

Nov. 11, 1947. i A. GABRIEL 2,430,764

PUMP

- Filed April 7, 1945 Y 2 Sheets-Sheet 1 Nov. 11, 1947. A. GABRIEL 2,430,764

' PUMP Filed April' '7, 1945 2 Sheefs-Sheet 2 FIG.3. 66

Patented Nov. 11, 1947 PUMP Adam Gabriel, River Forest, 111., assignor to Acme Industrial Company, Chicago, 111., a corpora tion of Illinois Application April 7, 1945, Serial No. 587,151

6 Claims.

This invention relates to pumps, and with regard to certain more specific features, to variabledelivery, positive-displacement, hydraulic pumps.

Among the several objects of the invention may be noted the provision of a pump of the class described having control means for substantially determining maximum delivery pressure with automatic volume control for maintaining volume as required by a fluid-consuming appliance; the provision of a pump of the class described which maintains control without the use of disadvantageous by-pass pressure relief arrangements which cause heating and thinning of hydraulic fluids; the provision of a pump of the class described which exactly supplies the volume under the desired pressure required by the appliance which is served, thus conserving power; and the provision of a pump of the class described which is simple to construct and maintain and which has an inherently long life. This invention is an improvement upon swash-plate pumps of the class described in United States Patent 2,341,768, dated February 15, 1944. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings, in which is illustrated one of various possible embodiments of the invention,

Fig. 1 is a side elevation of the pump on a reduced scale;

Fig. 2 is a right-end elevation of Fig. 1;

Fig. 3 is an enlarged, horizontal section taken on line 3-3 of Fig. 1, showing parts in a limiting operating position corresponding to a blocked outlet;

Fig. 4 is an enlarged longitudinal on line 44 of Fig. 2, certain internal parts being shown in elevation, the positions of parts being as in Fig. 3;

Fig. 5 is a vertical section taken on line 5-5 of Fig. 1 but on an enlarged scale;

Fig. 6 is a vertical section taken on line -45 of Fig. 1 but on an enlarged scale; and,

Fig. 7 is a vertical section taken on line '|l of Fig. 1 but on an enlarged scale.

As noted above, the scale of Figs. 1 and 2 is smaller than that of Figs. 3-7. Similar reference characters indicate corresponding parts throughout the several views of the drawings.

section taken.

Positive displacement pumps in many applications, particularly for pumping liquids, have certain advantages. Their chief disadvantages are that for variable volume service they are difiicult to build, particularly when at predetermined pressures automatic volume regulation is desired. The usual practice has been to design this class of pump for maximum volume under the desired pressures and then to by-pass some of this volume when it is not required by the receiving appliance. This involves a by-pass pressure-release valve or the equivalent. The resulting heating in the'hydraulic fluid, as well as the wire-drawing eifect on the fluid of the by-pass valve caused undesirable heating and viscosity changes in the fluid, as well as large losses of energy. Where attempts have been made to avoid the by-pass valve difficulties, variable delivery has been obtained by differential.

action between several pistons, that is, by variably phasing them without changing their individual stroke. This solution to the problem involved rather complex mechanical constructions difiicult to operate at high speeds. The present invention provides a simple, quiet, high-speed, variable-stroke, positive-displacement pump in which control of pressure may be maintained under any volume requirements within its range as imposed by the receiving appliance.

Referring now more particularly to the drawings, numeral 1 indicates a hollow cylindric case on which is bolted a head 3. This head has an inlet 5 and an outlet 1. Centrally the head carries a bearing 9 for a power shaft II. A lubricant retainer is shown at l3. The bearing 9 is greased by means of a grease passage 15 which leads from a lubricant supply fitting I! (Fig, 4).

At its other end the shaft II is supported upon a conical roller bearing 19 which is backed up by a thrust plate 2|, the latter being threaded into a cylindric extension 23 of the casing I.

Keyed to the shaft II is a cylinder block 25 having double-helix slinger threads 21. This block is rotary with the shaft ll. Exteriorly it is of cylindric shape, spaced within the case I as indicated in Fig. 4, and at the left end is formed with said helical slinger threads 21 which more closely fit Within the case. The normal rotation of block 25 is such that the slinger threads 21 tend to pump any leakage fluid toward the right as viewed in Figs. 3 and 4. The fluid here referred to is not the main pumpage of the pump, as will appear. This leakage may escape at port 28.

At spaced intervalsaround the axis of rotation of the shaft II are positioned cylinders 29. These are located parallel to the axis. They carry reciprocating pistons 3I. In the present example there are nine cylinders carrying nine pistons. Other numbers may be used. At its left end each piston 3| has a reduced neck 33, beyond which is a spherical ball end or head 35. Under each ball end 35 is a circular washer forming a rocker seat 3'1 having a female internal spherical shape which forms a bearing for a corresponding head 35. Since the pistons 3i and heads 35 are preferably made of steel, the seats 3! are made of some material forming a suitable bearing for the steel.

The seats 31 themselves rest upon a rocker disc 39, having suitable openings 4| for freely clearing the necks 33. These openings 4I allow for relative rocking between the rocker disc and the pistons.

The rocker disc 39 has an inside boss 43 in which is an internal spherical surface 45 engaging an external spherical surface 41 of a rocker seat 49. Thus the rocker disc 39 may rock in any plane relatively to the rocker seat 49.

The rocker seat 49 is slidable on the shaft II and its right-hand end .is made as a boss 5I which engages the inner periphery of a disheddisc Belleville spring 53. The outer periphery of this Belleville spring 53 rests upon a peripheral land 55 of a reaction washer 51. The latter is held in a recess at the left end of the cylinder 25. The Belleville spring 53, reacting from the land 55, biases the rocker seat 49, bearing 41 and pistons 3I toward the left. Thus slack is taken up, as will be clear.

All of the piston heads 35 engage a rotary race 59 of a swash plate assembly. The race is carried upon a thrust-bearing assembly 6I, annularly surrounding the shaft II. Bearing assembly BI is carried in an annular cradle 53 which carries lateral coaxial gudgeons 55. The gudgeons 55 are supported in bearings 61, said bearings being supported in sideward openings 69 of the case I. The common axis of bearings 61 and gudgeons G5 is perpendicular to the axis of shaft H. The outer races of the bearings 51 are retained by cover plates II.

On its top the cradle 63 is provided with a lubricant fitting 13 (Fig. 4) which is accommodated in an opening 15 having an upper cover plate 16 which may be opened for lubrication through the fitting 13. As will appear later, the fitting I3 rocks in the opening I5.

At its lower end (Fig. 4) the cradle 63 carries a ball control stud TI. This stud TI is caught between the head I9 of a compensating piston BI and a sliding spring retainer cup 83. Within the cup 83 is a spring 85 which reacts from an adjustable regulating screw 81. The piston 8| slides in a bushing 82 and responds to liquid pres sure in a cylinder 89 formed in the case I. This cylinder 89 communicates with a passage 9I in the head 3 which, as indicated by dotted lines in Fig. 3, communicates with the outlet port I. Thus it will be clear that the position of the stud I1 is controlled by the pressure in the cylinder 89 and hence by the pressure in the outlet. As the stud 'I'I moves, the cradle 53 rocks in the bearings 61, thus adjustably angling the rotary race 59. As the angle of this race 59 changes, the strokes of the pistons'3l into cylinders 29 are varied as the shaft II is driven from some outside power source. Also, the angle which the cradle will assume in response to a given pressure in the cylinder 89 is determined by the pressure from spring 85. This in turn is determined by the position of the adjusting screw 81. In short, the adjustment of screws 81 determines the pres sure at which the pump will operate, as will be clear.

At numeral 93 is shown a phasing disc valve which, angularlyconsidered, is held stationary with respect to the stationary head 3. This is accomplished by means of a dowel pin (Fig. 4). Axially considered, the disc is floating between the block 25 and head 3. This disc 93 is shown in detail in Figs. 3, 4, 6 and 7. It includes an inlet port 91 which is in communication with the inlet 5 (Fig. 3). It also includes an outlet port 99 which is in communication with the outlet 1. On the side of the disc (Fig. 6) which faces the rotary block 25 are partial circular grooves I 0| and I03 'in communication with the inlet port 91 and the outlet port 99, respectively. These grooves form communications with the cylinders 29 as the latter rotate. This is in order to place the cylinders in communication with the inlet 5 when the pistons 3i therein are axially retracting in suction, and to place them in communication with the outlet I when the pistons 3I are axially advancing in compression. The flat portions I05 between the grooves IN and I03 serve to seal off the inlet 9'! from the outlet 99.

As above indicated, the phasing disc 93 is separate from the shaft II and the rotary block 25 and also from the stationary head 3. The dowel 95 only prevents rotation. There are circular grooves I09, one on each side of the disc. These are in communication with one another through holes III. They are also in communication with the inlet as indicated by the radial slot H3 (Figs. 6 and 7). These grooves I09 also serve as suction returns for any leakage that occurs around the disc 93 from the outlet 99. In order to reduce to a minimum pressure on the thrust bearing I9, the ends of the cylinders 29 are restricted as indicated at I01. This provides for some axial pressure from the contents of each cylinder being applied upon the rotary block 25 (toward the right in Fig. 3) so as to offset pressure which is applied on the 'block 25 (toward the left) over areas between cylinders as they come into the range of the passages I III and I03. I

A side-thrust balancing feature is also employed in connection with the pistons 3|, which is as follows:

. Each is drilled axially as shown at H5 and crosswise as shown at III for conveying the hydraulic fluid which acts as a lubricant. This fluid reaches the walls of cylinders 29 from passages III via peripheral grooves II8. Balancing grooves H9 and I20 are used in each cylinder 29 and these are in communication with the grooves II8 throughout a substantial part of the stroke of each piston 3I. The members'cf each pair of grooves II 9, I20 are arranged on opposite ends and sides of their respective cylinders 29 to offset side thrusts on the pistons created by an angularity of the race 59. rangement is such that the grooves II9 near the outwardly extending parts of the pistons are trailing the pistons in revolving about the axis of shaft II; whereas the grooves I20 which are farther away from said piston extensions lead the pistons in their rotation about the axis of the shaft II. This is clear from Figs. 3 and 5. Thus during the compression stroke in any cycle wherein the piston side thrust is a maximum due to any angular position of the race 59 there is The ary Assume that the shaft II is'power-operated in the direction shown by the arrows in the various figures. Since at the start of rotation there is presumably no pressure in the outlet I,

there will be no pressure in the control cylinder Thus the spring 85 biases and anglesthe.

6 v I and the control cylinder 39 which compresses the spring 85 until a new balance is reached at a smaller angle of the race 59.

Any desired pressure at any given volumetric flow within the range of the device may be obtained by adjusting the screw 37.

In view of the above it will be seen that there is a balanced operating condition for each volumetric and pressure requirement of the appliance cradle stud TI to the right of the position shown in Fig. 4. This angles the cradle 63 and the race 59 and, as the cylinder block 25 rotates, each piston makes a suction stroke and a compression stroke during each revolution. In the lowest position of each piston, its cylinder is blocked off from grooves I9I and I93 by the lower fiat portion I of disc 93. As block 25 rotates counterclockwise (Figs. 5 and 6), each piston moves upward from this lowest positiori and also moves to the left as viewed in Fig. 3. When its cylinder comes into communication with groove lOI, fluid is drawn in from inlet 5 through inlet port 91 and groove II. This suction stroke continues until the piston has travelled to its uppermost position wherein its cylinder is blocked off from grooves IM and I03 by the upper flat portion I 95. The piston then moves downward and also to the right asv viewed in Fig. 3. When its cylinder comes into communication with groove H13, the piston forces fluid out throughgroove I93,.outlet port 99 and outlet i. This compression stroke continues until the piston has travelled back to its lowest position wherein its cylinder is blocked off from grooves IOI and I03 by the lower fiat portion I05.

Thus, fluid is transferred from the inlet 5 to the outlet 1 and builds up pressure in the latter and supplies the volume required by the consuming appliance attached to the outlet. As the volume requirement is met, pressure builds up in the control cylinder 89 and the piston 8| is pushed to the left against the reaction of spring 85, thus forcing back the cradle stud TI and reducing the angle from the perpendicular of the cradle 93. This also reduces the angle of the race 59 and hence the angle of the plane in which the heads operate. The result is to reduce the strokes of the pistons 3i. This stroke-reducing action goes on until the pressure in the control cylinder 89 is reduced to such value, due to the resultant decrease in volume delivered through the outlet, as to be counterbalanced by the reaction in spring 85. Under such balanced conditions the exact volume required by the appliance is supplied at a certain pressure determined by previous adjustment of the screw 81. The balance occurs at some given angle of the cradle 33 which is less than its starting angle.

Assume next that the appliance connected with outlet 1 admits a greater volume. This incipiently reduces the pressure in the outlet 1 and in the control cylinder 89 which permits the sprin 35 to expand and increase the angle of the cradle 63 and race 59. This increases the strokes of the pistons 3| and thus tends to counteract the incipient loss in pressure caused by the greater volumetric output. Finally a balanced condition is again reached.

Next, assume that the appliance in connection with the outlet I restricts the volume received. This incipiently raises the pressure in the outlet which is being served, the same being under manually adjustable automatic pressure control.

' Thus the pump automatically maintains steady conditions according to the requirements of the appliance.

Several important structural and mechanical features should be noted as follows:

As the heads 35 ride with the race 59 from a low point to a high point, they drive the pistons 3| through a compression stroke in the correct" phase relationship with respect to the outlet groove I93. This is apositive motion.

Positive motion during the suction phase of the action of each cylinder is obtained through the rocker disc 39. As one side of this disc rocks in one axial direction, the diametrically opposite side rocks in the opposite axial direction. Thus the disc functions as a simple lever across any diameter. ,This lever is pivoted on the ball and socket joint 45, 41. Thus a positive mechanical withdrawal is effected for a suction stroke of each of the pistons 3 I.

Also, the fulcrum for the disc 39 actin as a rocking lever is on the center of the Belleville spring 53 which in turn reacts at its edge on the circular land 55. This spring makes an essen-' tially stationary fulcrum but one which is resilient enough that any looseness is taken up between the disc 39, seats 37, heads 35, race 59, and the various parts of the thrust bearing 6i. Looseness is also taken up at the ball and socket joint 45, 91, spring 53 and washer 51. Thus quiet action is assured even at high speeds.

Furthermore, the seats 31 may slide on the surface of the disc 39 as well as rock under the heads 35. This compensates for relative radial motions between the swinging ends of the disc 39 and the reciprocating ball ends 35 of the pistons. Any bias thrust from the angled race 59 against the piston heads 35 which tends to cock the pistons 3I in their cylinders 29 tends to be counteracted by the fluid pressure in the grooves I I9.

- Any leakage which escapes under pressure from the grooves I93 and port 99 past the valve disc 93 will either pass toward the center and be received by the grooves I99, II I and be returned to the suction port 91 via groove H3, or some may work out radially in between the cylinder 25 and the case I. From the [latter it will pass out of the drain 28. This latter leakage is prevented from flowing to the cradle operating mechanism by the slinger 21. Any leakage past the pistons 3| moves radially toward the slinger 21 and is pumped thereby back toward the, drain 28. Thus the operating linkage to the left of the slinger is kept free of pumpage and may be independently 7 leakage pressure on the right end of cylinder block 25 which tends to push it and the shaft H to the left.

It will be observed that the invention comprises more than the ordinary swash plate pump which is subject to the same disadvantages as ordinary reciprocating pumps, so far as is concerned the matter of pressure and volume control. The swash plate assembly including race 59 is automatically adjusted in response to pressure in the outlet, thereby compensating for differences in the volumetric requirements of the appliance which is being served with hydraulic pressure fluid.

It will be seen from the above that besides providing an automatically-controlled, variabledelivery, positive-pressure displacement pump, that I have produced novel features in the swash plate construction itself. Besides, the swash plate type of pump construction is itself advantageous because of its compactness. Thus in the present example a nine-cylinder pump is confined within the relatively small cylinder composed by the casing I. This is due to the circular distribution of the pump cylinders and pistons with their axes parallel to the axis of rotation of the shaft 1 I.

While the present pump will handle any ordinary liquid pumpage, such as water, gasoline, oil

. and the like, it is preferable that when this pumpage acts simply as a hydraulic pressure link between the pump and a power appliance the pumpage have a lubricating quality. In such instances oil, hydraulic brak fluid and similar substances are preferable.

In view of the above it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A pump comprising a casing, a, pump shaft extending through the casing, a head closing one end of the casing having an inlet and an outlet therein, a swash plate assembly in said casing including an annular cradle surrounding said shaft and axially spaced from said head, said cradle being pivoted for rocking movement upon an axis substantially perpendicular to and intersecting the axis of said shaft, 2. block'having axially extending open-ended cylinders therein carried by said shaft for rotation therewith intermediate said swash plate assembly and head, the ends of said cylinders adjacent said head communicating successively with said inlet and outlet, pistons reciprocating in said cylinders having portions extending out of the other ends of the cylinders, single spring means for biasing all of' said pistons to maintain their extending portions in engagement with said swash plate assembly, a

control stud extending outward from said cradle substantially radially with respect to the pivotal end of the casing having an inlet and an outlet therein, a swash plate assembly in said casing including an annular cradle surrounding said shaft axially spaced from said head, said cradle bein pivoted for rocking movement upon an axis substantially perpendicular to and intersecting the axis of said shaft, a block having axially extending open-ended cylinders therein carried by said shaft for rotation therewith intermediate said swash plate assembly and head, the ends of said cylinders adjacent said head communicating successively with said inlet and outlet, pistons reciprocating in said cylinders having portions extending out of the other ends of the cylinders, means for biasing said pistons to maintain their extending portions in engagement with said swash plate assembly, a control stud extending from said cradle substantially radially with respect to the pivotal axis of said cradle and in the plane thereof, a spring engaging said stud to rock the cradle in one direction, a control cylinder in communication with said outlet, and a control piston movable in said control cylinder and engaging said stud for biasing said cradle to rock in the other direction, said means for biasing said pistons comprising a rocker disc mounted for axial sliding and universal rocking movement on said shaft between said swash plate assembly and block,

means for biasing said disc to move axially toward said swash plate assembly, and means on the extending portions of said pistons engaged by said disc for biasing said extending portions into engagement with said swash plate assembly.

3. A pump comprising a casing, a pump shaft extending through the casing, a head closing one end or the casing having an inlet and an outlet therein, a swash plate assembly in said casing including an annular cradle surrounding said shaft axially spaced from said head, said cradle being pivoted for rocking movement upon an axis substantially perpendicular to and intersecting the axis of said shaft, a block having axially extending open-ended cylinders therein carried by said shaft for rotation therewith intermediate said swash plate assembly and head, the ends of said cylinders adjacent said head communicating successively with said inlet and outlet, pistons reciprocating in said cylinders having portions extending out of the other ends of the cylinders, means for biasing said pistons to maintain their extending portions in engagement with said swash plate assembly, a control stud extending from said cradle substantially radially with respect to the pivotal axis of said cradle and in the plane thereof, a spring engaging said stud to rock the cradle in one direction, a control cylinder in communication with said outlet, and a control piston movable in said control cylinder and engaging said stud for biasing said cradle to'rock in the other direction, said'means for biasing said pistons comprising a rocker disc supported for axial sliding and universal rocking movement on said shaft between said swash plate assembly and block by means of a ball and socket joint slidable on the shaft, said extending portions of said pistons passing through openings in said disc and having heads on their ends, seating means between said heads and the disc adjacent said openings, and a dished-disc type spring reacting between said block and said ball and socket joint for biasing said disc and said pistons toward said race.

4. A swash plate pump comprising a casing said chamber remote from said compartment and having an inlet and an outlet therein, a block journalled for rotation coaxially in said chamber, said block having axially extending open-ended cylinders therein, the ends of said cylinders adjacent said head communicating successively with said inlet and outlet, pistons reciprocating in said cylinders and extending from their other ends into engagement with swash plate means mounted in said compartment, said block being provided on its end adjacent said compartment with a helical fluid slinger rigid with the block and closely fitting within said chamber, said slinger being rotatable with'the block and adapted to pump any fluid which has leaked into said compartment from said cylinders away from said compartment toward said head.

5. A swash plate pump comprising a casing having a cylindric chamber adjacent a swash plate compartment, a head ,-closing the end of said chamber remote from said compartment and having an inlet and an outlet therein, a block journalled for rotation coa-xially in said chamber, said block having axially extending open-ended cylinders therein, the ends 01 said cylinders adjacent said head communicating successively with said inlet and outlet, pistons reciprocating in said cylinders and extending from their other ends into engagement with swash plate means mounted in said compartment, said block being peripherally provided on its end adjacent said compartment with a helical fluid slinger closely fitting within said chamber, the remainder of said 10 its axis, one end of each of said cylinders being adapted successively to communicate with a pump inlet and a pump outlet, pistons reciprocable in said cylinders and having extensions from their other ends, angular swash plate means engageable by said extensions for reciprocating said pistons as the block rotates, said swash plate means tending to cause side thrust on said pistons as they rotate with the block, each of said cylinders being provided with a groove adjacent said one end thereof in the side of said cylinder which leads with respect to the direction of rotation of said block, each of said cylinders also being provided with a groove adjacent its other end in the side of said cylinder which trails with respect to the direction of rotation of said block, each of said pistons having fluid passages therein for supplying fluid under pressure from said cylinders to said grooves, the fluid under pressure in said grooves tending to counteract said side thrust.

ADAM

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,135,515 Hull et al Nov. 8, 1938 2,284,111 Vickers May 26, 1942 2,284,169 Robinson May 26, 1942 2,288,768 Zimmerman July 7, 1942 2,299,234 Snader et a1 Oct. 20, 1942 2,299,235 Snader et a1 Oct. 20, 1942 2,300,009 Rose Oct. 27, 1942 1,772,828 Egersdorfer Aug. 12,1930 1,912,284 La Brie May 30, 1933 2,299,233 Hofier Oct. 20, 1942 2,303,955 Rose Dec. 1, 1942 2,313,407 Vickers et al Mar. 9, 1943 2,337,821 Huber Dec. 28, 1943

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