US2001336A - Hydraulic device - Google Patents

Description

May 14, 1935. P. v. vAG ET AL 2,001,336

HYDRAULIC DEVICE Filed May 31. 1930 4 Sheets-Sheet l 3b.5 4l 1l 11/1m6% 2 uw m. 4l

`May 14, 1.935. P. v. vAG vET AL 2,001,336

HYDRAULIC DEVICE 4 Sheets-Sheet 2' Filed May 51, 1930 May 14, 1935.

- P. v. VAG ETAL HYDRAULIC DEVICE Filed May 3l, 1930 4 Sheets-Sheet 3 l B /3111 C B I www Wm' May 14, 1935#- 1 v. vAG 'Er-AL 2,001,336

HYDRAULIC DEVICE Filed May s1, 1950 4 sheets-smeetl f1 3' s' 10 4" 1 l 1 m 2 o, n a h h M h L m 180 V 180 Patented May 14, 1935 UNITED STATES HYDRAULIC DEVICE Paul v. Vgv and Edmond Uher, Budapest,

Hungary; Vago said Ulier assignor to said von Application May 1, 1930, serial No. 458,734

12 Claims.

The invention relates to hydro-dynamic device which can be used eitheras a pump or as a hydraulic motor and which is, substantially more simple than similar devices known up to the present, operates with high eiciency, and is capable of being controlled between wide limits. In 'ad- Vdition hereto the new device owing to its design is also suitable for being used as a hydraulic transmission gear, for which purpose two of these devices are employed in mutual connection, one of the devices according to the invention operating as a puinp whilst the other operates as a hydraulic motor, the whole set being capable of being controlled at will either on the pump-side or on the hydraulic side, or on both sides.

Referring to the drawings:

Figure 1 shows a longitudinal section through the control valve and associated parts of a hydraulic machine according to the invention;

Figure 2 vshows a longitudinal section of the machine as a whole, on a smaller scale;

In Figure 3, parts of the device according to the invention are shown, partly in outside view and partly in section, in order to illustrate the method of driving the control shaft;

The left hand part of Fig. 4 illustrates a cross section of the device, the section being taken along line a-b of Fig. 2;

The right-hand part of Fig. 4 illustrates a lon'- gitudinal section of the device, the section being taken along linea-c-d of Fig. 2;

Fig. 5 is a diagrammatic horizontal section of the device, the section being taken along plane e-f of Fig. 4;

Figs. 6 and 7 serve to illustrate various methods of control;

Fig. 8 is a section of Ithe mechanism employed for the purpose of ensuring automatic control of the pressure; and

Fig. 9 is a section of a part of the device, shown in order to illustrate the method of operation of the control mechanism.

In Figure 1, 6 denotes the piston of a hydraulic machine, which is driven from a crank 2 through a connecting rod l, and reciprocates in a cylinder 5. Perpendicular to the longitudinal axis of the 1I cylinder 5 is a bore for a slide valve, which therefore moves perpendicularly to the pump piston 6, and controls a suction passage 3 and a delivery passage 4.

The slide valve consists of two valve pistons, of which the valve piston |Il| controls the suction passage and the valve piston controls the delivery passage. The slide valve piston |0| is secured to or is integral with a shank member Ill.

Germany June 14, 1929 The valve piston controlling the delivery passage 4 is slidablymounted on the shank I0. At the end of the shank v||l is provided a packing or sealing piston I2, and between this piston I2 and the valve piston there is aspring 2|, which 5 pressesfthe movable valve piston against an' annular bead or collar |03 on the shank l0. The valve piston can` therefore move in an axial direction on the part I0 of the shank I0.` It carries at the left-hand end an annular edge 2.2, in l0 which the collar |03 on the shank |0 lodges in the position of the valve piston shown. The collarA7 |03 and the annular edge 22 form a cataract 'shock-absorber or dashpot, as the liquid can only escape slowly from the space between the l5 collar |03 and the pistonll under the lpressure of the spring 2|. The slide valve consisting of the parts IUI, l0, and |2 is subject to the action of an eccentric 20, which, as hereinafter explained, revolves with the shaft I9, and displaces 20 the valve against the spring I8. In Figure 1 the pump piston 6 is in its upper dead-centre position and the valve body in its mid position. The latter slides to and fro to left and right of the line X-X when the eccentric 20 revolves. In 25 the' mid position illustrated the suction passage 3 is exactly? covered, so that the latter is opened immediately' when the slide valve moves to the left. The slide valve piston however, has positive lap, so that the delivery passage is only 30 opened when the valve has moved Ito the right a distance equal to the lap. This arrangement of the valve controlling the delivery passage has the advantage that no shocks can occur in the machine, which therefore runs smoothly even at 35 very high liquid pressures, and the further ad- ,vantages that the centre line X-X about which the controlling valve oseillates can be displaced relatively to thepassages 3 and 4, and therefore shifted to the left or right out of the position 40 shown'inliigure 1, as hereinafter described, and in this way the quan-tity of liquid delivered by the pump can be regulated from zero to a maximum. This method of operation of the pump is explained with reference to Figures 2, 3 and 4.

A practical embodiment of the invention is illustrated in the drawings. The shaft II of the device operates three pumps A, B, C, these pumps being of entirely similar design but keyed on at diierent angles Fig. 4; one lof these pumps is 50 shown in Fig. 2 in longitudinal section, the section being taken in a plane perpendicular to the plane of Fig. 4. With the cranked shaft II there cooperate the connecting rod I3 and the crosshead pin I4, connected to the same. The said 55 whilst its outside surface is turned on a lathe to the exactshape required. The piston 6I of the pump joins on to Ithe cross-head I5 by means of a spherical pad I6 capable of sliding displacement in the lateral direction. The piston is secured in the cross-head I5 against the action of any force pulling it in the axial directionby-means o f the dovetail connection I1. Communication between the pump chamber 5 andthe suction conduit 3 or the delivery conduit 4 is controlled by slidevalves IDI and I I, which latter are connected with Aone another by means of the member I0. The

slide-valve part controlling the opening and closing of the delivery conduit 4'A is shaped so as to enable the pump to workwith positive lap.

The control shaft I9 is driven by means of the gear Wheel 24 shown in Fig. 3. `-'I'his gear wheel engagesI with the gear wheel 25, revolving loosely on the xed shaft .26, and is driven by means of chain 21 by the chainv sprocket 28 keyed on the main shaft II. The control shaft I9 is supported in bearings arranged in the cranks .I9I which latter are capable of being pivoted in the direction of arrow 30 around the fixed pivot 26.

The three pumps A, B, C are connected in parallel. For this purpose the delivery conduits 4 of the individual pumps are connected with one another by means of the common bore-hole IV also shown in Fig. 5. `In order to effect the damping of the pulsations of the volume of liquid delivered as far as possible, a tank 14 of suitable size, filled,

of course, with liquid, should preferably be inserted into the conduit IV which tank acts like a capacity and by its elastic changes of volume balances the rapid variations of pressure of the column of liquid contained in conduit IV. The suction conduits 3 of the pumps A, B, C may likewise be connected with one another by means of the longitudinal channel III.' If the pump ro- A,

tates at a high speed, so that there is a possibility of the column of liquid drawn in being inter- A rupted, it is advisable to insert a tank 15 of suitable shape and capacity into the suction conduit III as well; the supply-of the liquid into this last named tank may for instance be effected by means of a separate small pump. Another possible method is to connect the suction chambers 3' of the pumps 'A, B, C with the interior of the liquid tank 32I by means of very short bore-holes 54, Fig. 2. In this case tank 32 may preferably, as shown on the drawings, be arranged so as to form the casing of the pump:

As is evident from Figs. 2 vand 4, bores of the pumps, the bore-holes in which the control slide-valves run, and, finally, the boreholes connecting the suction-chambers with one another,` and those connecting the delivery chambers of the individual pumps with one another form groups of parallel bore-holes, each group being either parallel or perpendicular to each `of the other groups. Owingr to this circumstance.

all these bore-holes may be very efliciently provided by drilling them simultaneously in a forged block 3|. The compactness and standard character of the design resulting in this way renders it particularly suitable for high pressure pumps and hydraulic motors.

the piston 2,001,336 cross-head pin is riveted to the connecting'rod,

shaft I9--which latter is driven by means of chain 21 and gear Wheels 25, 24,-wil1 likewise effect the alternating motion of the slide-valves I0.I and I I, the said movements of the pistons and of the slide-valves being synchronous. If the relative positions of the pistons 6I and of the corresponding slide-valves I!" and Il are such that -in the dead centre position of the. piston the slide valves are in their middle position, the

slide-valves will perform symmetrical oscillations around the middle position, that is to say the pump will draw in liquidduring the whole time of the suction stroke of the piston SI and deliver liquid during the whole time of the delivery stroke of the piston 6 I.

TheU quantity of liquid supplied by the pump can be controlled by shifting the/slide-valve body IUI, Ill, II from the middle position so that the centre line of oscillation of the slide-valve will come to be situated to the left of the symmetrical position diagrammatically shown in Fig. 2. In this case the pump chamber 5 will remain connected with the suction conduit 3fduring a longer time than corresponds to a complete stroke of the piston 6 I. On the other hand, the time during which the chamber of the pump will remain in communication with the delivery conduit 4 will' be correspondingly shorter and accordingly the pump will deliver a correspondingly smaller quantity of liquid into the delivery conduit. Notably the supply of liquid into the delivery conduit 4' will start only when the slide-valve body IOI, II), I I has already performed such part. of its oscillation towards the right hand side as to close the suction conduit 3. If therefore the slidevalve body IIJI, I0, II is displaced towards the left in a measure corresponding to half the stroke of the slide-valve no liquid at all will be supplied by the pump as the delivery conduit 4' will not be opened at all. This method of control 1s made possible by the device already described.

Notably, during `those periods of the delivery stroke when the slide-valve body IUI, I0, II has already shut-off the pump chamber 5' from the suction conduit 3', the liquid displaced by piston 6I tends to displace the piston 22, which serves to prevent leakage, in the direction opposite to the time it is not possible for the pressure in the pump chamber 5 to increase in a detrimental extent.

'I'he control described is effected byhand by means of the device illustrated in Figs. 2 and 4 or automatically by that illustrated in Fig. 8. The slide-valve body IOI, I9`, -II in Fig. 2 is capable of being shifted from the symmetrical middle position by shifting the control shaft I9 towards the left, for which' purpose the. control shaft I9 is supported in bearings so as to be capable of being pivoted around pivot 26 in the 4manner described. For the purposeof control,

accordingly, the crank support arrangement I9I is deflected towards the left in the sense of arrow 30 in Fig. 3. During this time the engagement betweenthe gear wheels- 24, 25 remains unchanged.

This deflection of shaft I9 may be effected in an automatic manner so as to be functionally dependent upon the pressure of the fluid delivered. The automatic control gear employed for the purpose of the latter alternative is shown in Fig. 8. By employing this device instead of tlc manual control it is possible to ensure that the pump will maintain a'constant pressure regardless of the variation of the quantity of liquid required, whilst on the other hand it enables the employment of a safety valve to be dispensed with. The essential element of the automatic control device is the differential piston 34 running in the bore-hole 33 provided in the plane g-h Fig.'4 of the forged pump block described above. The cylinder space 35 of the differential piston communicates by means of the bore-holes 36, 36|, and 362 provided in the piston body and through the non-return ball valve 31 with the delivery conduit 4' of the pump. Both ends of the piston body 34 project from the bore-hole 33 running through the whole length of the block. On the left hand end of the piston 34 one lever arm of the bell crank lever 38 is supported, whilst the other lever arm of this bell crank lever is connected by means of a swiveljoint with the bottom end of rod 42| supported in the manner of a bolt in nut 42. Nut 42 is capable of being rotated by means of hand-wheel and its bottom surface reposes on the spring 39| resting against shoulder 39, which arrangement enables the preliminary tension of the spring to be adjusted by means of the hand wheel 40. The other, i. e. right-hand end of the differential piston 34 is connectedwith the control shaft |9 by means of the swivel-joint 43 and the bearing 43|.

If liquid pressure of inadmissibly large magnitude is set up in the delivery conduit 4 of the pump, this pressure will be propagated through the bore-holes 362, 36|, and 36 to the cylinder space 35 and will displace the piston 34 towards the left against the action of spring 39|. During this time the piston 34 will carry shaft I9 along with itself by means of swivel-joint 43 and bearing 43|, owing to which the oscillation centre line of the slide valve |0 will likewise be shifted in the manner already described above. If the pressure in the delivery conduit 4 is subsequently diminished again, the spring 39| will again return the differential piston 34 into the extreme position shown in Fig. 8. In order to prevent the describedmovements of the Adifferential piston becoming too rapid and causing the occurrence of knocks, the path of flow of the liquid is throttled. For this purpose an imperfectly closing ball valve is employed. This valve permits the liquid only to flow back slowly when the piston 34 is being returned. A

The control diagram of the method of control described is shown in Fig. 6. If the oscillation centre line of the slide valve body |0|, |02, |0 is shifted towards the left from the symmetrical middle position, the pump chamber 5' will communicate with the delivery conduit 4 only during the time in which the crank 2' is moving from positlonfm to position n. During this time the piston 6| will perform the stroke h'. In all other crank positions the pump chamber 5' cornmunicates with the suction conduit 3. The change over points m and n of the slide valve body |0|, |02, |0 are situated in symmetrical positions relatively to the middle position of piston 6| and with the diminution of the delivery period will be shifted more and more towards the point at which the quantity of liquid delivered is reduced to zero. During this time, however, the piston speeds at which the points of changingover m and "n are reached will be continually increasing. On the other hand, the larger thel piston speed, the larger will be force acting on piston In order to prevent detrimental shocks which might arise from this it is possible to supplement the capacity of the pump chamber by the addition of space 52 shown the accelerating in Fig. 9, the quantity of cushioning liquid between the piston 6 or 6| and the piston which serves to prevent leakage being thus increased.

It is however also possible to control the slide valves |0|, |02 in such a manner as to keep the angle of advance opening of the slide-valves constant, or in other words to keep the positionin which the slide-valves present the conditions shown in Fig. 9 constant, whilst at tht same timevarying the degree of `admission of the pump at will. For this purpose the control gear shown in Fig. 9 is employed. j

Piston .6| is driven from the main shaft II. The gear wheel 45 keyed on the main shaft II engages with the gear wheel 46 and drives shaft 54 at a speed corresponding to a transmission ratio of 1:2. In the lever arm |9|' capable of revolving around the shaft 54 as about a pivot, the pin I9' is supported so as to be capable of being likewise deflected. This pin I9 serves as a shaft for the gear wheel 48 meshing with the internal toothing of the gear wheel 46, the gear ratio between these two gear wheels being 2:1, so that the number of revolutions per minute of the gear wheel 48 is equal to the number of revolutions per minute of the gear wheel 45. The crank pin 5| arranged in the gear wheel 48, the radius of which crank pin is equal to the radius of the pitch circle of gear Wheel 48. moves the slide valve body |0|, |02, |0 by means of the connecting rod 50, the bell crank lever 49 and the coupling rod 55. If this control shaft I9 is deflected in the direction of arrow 41 the gear` wheel 48 will run round the internal teeth of the gear wheel 46 and owing to the diameter ratio of 1:2 stated, the pin 5| will move along the diagonal in the straight line O O. If the connecting rod 50 is made of sufcient length, the slide valves |0| and |02 will be displaced during the shifting of pin 5| 4to an extent so slight as to be practically negligible, but in proportion to the shiftingy of the centre line of shaft I9 the centre line of oscillation of the slide-valves will be displaced towards the left without the angle of advance opening of ,the slide-valve being altered.

'Ihe diagram of control in the case of the device being used as a pump, is shown in Fig. 7. The control device shown in Fig. 9 is preferably adjusted so as to make the changing-over corresponding to an advance opening of a permanent degree, take place at the 180 position of the crank, whilst the changing-back, corresponding to varyingdegrees of admission, should take place in the position "m between the 180 and the 0 position, the pump having been drawing in liquid during the time of the stroke h.- The sense of rotation is indicated by the arrow.

On the other hand if it is desired to use the device described as a hydraulic motor, it will be preferable to effect .control in the manner shown on the right-hand side of the diagram in Fig. 6, i. e. the control gear will be adjusted so as to make the changing-over remain permanently in the dead-centre position marked 0 and cause changing-back to be effected between the 0 and 180 positions, for instance in position M. In this case the hydraulic motor has obtained highpressure liquid during the time of the stroke h, and has performed the corresponding amount of work. 'I'he sense of 4rotation is indicated by the arrow.

What we claim is:

' l. A pump comprising a cylinder, a suction passage, a delivery passage, a piston reciprocating in the cylinder, a valve passage 'extending transversely to the direction of movement of the piston and communicating near one end with the suction passage and near the other end with the delivery passage, the central portion of the valve passage being in communication with the interior of the cylinder, a control valve reciprocating in the valve passage, the said control valve comprising two parts, one of which controls the suction passage and the otherthe delivery passage, the part controlling the delivery passage being displaceable in relation to the part controlling the suction passage, and means for shifting the mean position about which the control valve reciprocates relatively to the suction and delivery passages. Y

2. A pump comprising a cylinder, a suction passage, a delivery passage, a piston reciprocating in the cylinder, a valve passage extending transversely to the direction of movement of the piston and' communicating near one end with the suction passage and near the other end with the delivery passage, the central portion of the valve passage being in communication with the interior of the cylinder, a control'valve reciprocating in the valve passage, the said control valve comprising two parts, one of 'which controls the suction passage and the other the delivery passage, the part controlling the delivery passage being longitudinally displaceable in relation to the part controlling the suction passage, and resilient supporting means for the said displaceable part of the control Valve.

3. A pump comprising a cylinder, a suction passage, a delivery passage, a piston reciprocating. in vthe cylinder, a valve passage extending transversely to the direction of movement of the piston and communicating near one end with the suction passage and near the other end with the delivery passage, the central portion of the valve passage being in communication with the interior of the cylinder, `a control valve reciprocating in the valve passage, the said control valve comprising two parts, one of which controls the suction passage and the other the delivery passage, and the said valve further comprising a shank common to the two said parts, the part controlling the suction passage being xed to the said shankand the part controlling the delivery passage being displaceably mounted thereon, a shoulder onthe shank adapted to limit the movement of the displaceable valve part, and a spring tending to press the displaceable valve part in the direction of the shoulder against the fluid pressure in the cylinder and the` central portion of the valve passage.

4. A pump comprisinga cylinder, a suction passage, a delivery passage, a piston reciprocating in the cylinder, a valve passage extending transversely to the direction of movement of the piston and communicating near one end with the suction passage and near the other end with the delivery passage, the central portion of the valve passage being in communication with the` interior of the cylinder, and a control valve reciprocating in the valve passage, the said control valve comprising a shank, a part which controls the suction passage mounted fast on the shank, a part which controls the delivery passage mounted displaceably on the shank, a shoulder on the shank adapted to limit the movement of the displaceable valve part, resilient means tending to press the vdisplaceable valve part against the shoulder, and a ange on the displaceable valve part surrounding the shoulder and forming with the shoulder a shock-absorbing dash-pot.

-the vvalve control member.

' part valve capable of moving transversely to the 5. A pump comprising a cylinder, a suction passage, a delivery passage, a piston reciprocating in the cylinder, a valve passage extending transversely to the direction of movement of the piston and communicating near one end with the suction passage and near the other end with the delivery passage, the central portion of the valve passage being in communication with the interior of the cylinder, a control valve reciprocating in the valve passage, the said control valve comprising a shank, a part which controls the suction passage mounted fast on the shank, a part which controls the delivery passage mounted displaceably on the shank, a shoulder on the shank adapted to limit the movement of the displaceable valve part, resilient means tending to keep the displaceable valve part pressed against the shoulder, and means for shifting the mean position about which the shank of the control valve reciprocates relatively to the suction and delivery passages.

6. A pump comprising a main shaft, a reciprocating piston, a driving connection between the reciprocating piston and the main shaft, a control valve capable of moving transversely to the line of movement of the piston and adapted to control the admission and discharge of -liquid operated upon by the piston, the said valve consisting of a shank and two valve bodies so mounted on the shank as to be displaceable relatively to one another, a pairv of rockably mounted swing levers, a, valve control shaft journaled in the swing levers, means for driving the valve control shaft from the main shaft, and means actuated by the valve control shaft for imparting reciproi cating motion tothe valve, the mean position| about which the valve reciprocates being variable according to the position of the swing levers.

7. A pump comprising a reciprocating piston, a two-part valve capable of moving transversely to the line of movement of the piston and adapted to control the admission and discharge of liquid operated upon by the piston, means for imparting reciprocating motion to the valve, a valve control member capable of shifting the mean position about which the valve reciprocates, and means controlled by the pressure liquid for adjusting 8. A pump comprisinga reciprocating piston, a two-part valve capable of moving transversely to the line of movement 'of the piston and adapted to control the admission and discharge of liquid operated upon by the piston, a pair of rockably mounted swing levers, a valve control shaft journaled in the swing levers, means actuated by the l valve control shaft for imparting reciprocating motion to the valve, a valve control piston acted upon in one direction by the pressure liquid and adapted when actuated to move the valve control lever in -such a way as to shift the mean position about which the valve reciprocates, at the same time rocking the swing levers, and a spring tending to force the valve control piston in the direction opposite to that in which the pressure liquid` tends to drive it. l.,

9. A pump comprising a main shaft, a recipfrocating piston, a driving connection between the J reciprocating piston and the main shaft, a twoline' of movement of the piston and adapted to control the admission and discharge of liquid operated upon by the piston, a revolving cran driven from the main shaft, the axis of rotatio of the crank being adjustable transversely to i axial direction, and means for converting th rotation of the crank into a reciprocating motion of the valve.

10. A pump comprising a main shaft, a reciprocating piston, a driving connection between the reciprocating piston and the main shaft, a control valve capable of moving transversely to the line of movement of the piston and adapted to control the admission and discharge of liquid operated upon by the piston, the said valve consisting of a shank and two valve bodies somounted on the shank as to be displaceable relatively to one another, an internally toothed wheel driven from the main shaft, an externally toothed Wheel of half the pitch diameter of the internally toothed Wheel meshing with the latter, a crank pin mounted at the periphery of the externally toothed Wheel, and rodding connected with the crank pin and adapted to convert the rotary motionof the crank pin into reciprocating motion of the valve.

11. A pump comprising an undivided cylinder block, a cylinder, a suction passage and a delivery passage all formed in the cylinder block, a piston reciprocating in the cylinder, a control valve capable of moving transversely to the line of movement of the piston and adapted to control the admission and discharge of liquid to and from the cylinder, the said valve consisting of a shank and' two valve bodies so mounted on the shank as to be displaceable relatively to one another, means for. imparting reciprocating motion to the valve, and means for shifting the mean position about which the control valve reciprocates.

12. In a variable delivery pump the combination of a plurality of cylinders and coacting plungers, driving means for effecting relative reciprocation between each of said plungers and cylinders, to effect a suction stroke and a pressure stroke, an intake passage, a discharge passage, valve mechanism operated in'timed relation with said driving means for effecting communication between said cylinders and said intake passage throughout each suction stroke and between said cylinders and said discharge pass'agevduring a portion of each pressure stroke, and means for regulating said valve mechanism to vary the period of communication between said cylinders and said discharge passage to thereby vary pump delivery.

PAUL v. vG. EDMOND UHER.

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