US2211598A - Hydraulic operator - Google Patents

Description

Aug. 13, 1940. T. w. DRn-:SCH

' HYDRAULIC OPERATOR Inventor:

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Patented Aug. 13, 1940 PATENT OFFICE 2,211,593 HYDRAULIC OPERATOR Theodore W. Driesch, Scotia,` N. Y., asslgnor to General Electric Company, a corporation of New York Application August 6, 1937, Serial No. 157,749

8 Claims.

This invention relates to hydraulic operating mechanism, more particularly to hydraulic operating mechanism in which a centrifugal impeller type pump arranged within a cylinder containing pressure on opposite sides oi' a piston movably I mounted within the cylinder thereby to eect movementl of the piston, and it has for an object the provision of a simple, reliable, and improved device of this character.

More specifically, the invention relates to hydraulic mechanism in which the piston is caused to move in an upward direction in response to iiuid pressure when the pump is energized, and in which the piston is returned to its initial position by the force of gravity when the pump is deenergized, and a further object of the invention is the provision of means for controlling the passage between the discharge of the pump and the lower side of the piston thereby to control the speed of the up stroke of the piston.

A still further object of the invention is the provision of additional means in the passage between the discharge of the pump and the piston L35 for controlling the speed of the down return stroke of the piston and so to arrange these two speed controlling means that each performs its function without interference from the other.

In carrying the invention into effect in one form thereof, a piston is movablyr mounted in a cylinder containing a liquid, and a. centrifugal pump is provided for developing a fluid pressure to effect movement of the piston. The pump housing is provided with an intake passage communicating with the space above the piston and with one or more discharge ports communicating with the space beneath the piston. A baille plate is provided in the passage between the discharge port and the lower side of the piston. This plate is arranged to close the passage when the pump is deenergized and to move in response to fluid pressure to open the passage thereby to effect upward movement of the piston, and means are provided for adjustably limiting the opening movement of the bale plate thereby to control the speed of the up stroke of the piston. In addition, valve means are provided in the baiile plate to provide for return flow of the liquid through the discharge port and downward return stroke of the piston in response to deenergization of the pump.

For a better and more complete understanding of the invention, reference should now be had to the following specification and to the accompanying drawing in which Fig. 1 is an elevation partly (ci. en -s2) in section taken on the line I-I of Fig. 2; Fig. 2 is a plan view with parts broken away; and

Figs.'3 and 4 are details.

Referring now .to the drawing, a cylindrical liquid container Ill is provided with a cover plate Il upon which an electric driving motor I2.is vertically mounted. The cover plate II is constructed to provide an integral supporting platform I3 a short distance beneath the top of the container I0.

The cylinder I is filled with a suitable fluid medium, such for examplev as oil, to a point substantially level with the platform I3. A piston I4 is arranged within the cylinder IIJ for vertical movement, and this vertical movement is transmitted to an external load by means of a pair of connecting rods I5. The lower ends of these connecting rods I5 are secured by suitable fastening means I6 to the piston I4', and the upper ends of these connecting rods extend through the cover plate I I and are secured to a cross-head I1 which is adapted to be connected to a suitable load. At the bottom of the container is an impeller type pump illustrated as comprising a housing I8 within which an impeller I9 is rotatably mounted. The housing I8 is provided with suitable, centrally disposed intake passages 20, together with a plurality of discharge ports 2| arranged circumferentially in the housing I8. Owing to the section taken in Fig. 1 of the drawing, only a single discharge port 2| is clearly visible in this figure. However, the circumferential arrangement of these ports in the housing is clearly shown in Fig. 2.

As shown, the pump housing member I8 is secured by suitable fastening means to the lower extremity of a tubular member 22, the upper extremity of which is suitably secured to the supporting platform I3. Openings 23 are provided in the wall of the tubular member `22, thus providing communication from the space above the piston I4 to the intake passages 20 of the pump. It will also be clear that the walls of the tubular member 22 serve as a partition means between the intake passages and discharge ports 2|, and thus confine the discharge of the pump to the space beneath the piston.

A vertical drive shaft 24 is rotatably mounted in a bearing 25 in platform I3 and in a bearing 26 which is centrally mounted in the pump housing I8. This drive shaft 24 is connected to the motor shaft 21 by suitable coupling means 28 so that rotation of the motor produces rotation of the pump impeller I8.

For the purpose of controlling the speed of is provided in the passage between the discharge 4 orifices 2| of the pump and the space beneath the piston. its shown, this bame plate is inthe form of a ilattened ring surrounding the central intake of the pump 'housing and covering the circumferential row oi'l discharge-ports 2 I. When the pump is deenerglzed' and at rest, .the baille plate 29 is seated snugly against thepumphousing so as to cover the discharge ports and out oi'l communication between the discharge portsand the space beneath the piston. A. hole 39 is provided in. the bale plate 29, and a stud 3| 'prof jects through. this hole and screws into the hou's ing I9. The dlameterof thefhole 30 is sufiiciently larger than die diameter of the stud 3| to al-Q low the barile piate 29 to tilt or rotate through a small angle in a clockwise direction as viewed in Fig. l so as to uncover the discharge ports 2|. The stud 3| is provided with a spring 32'which presses the right-hand end-.of the baille plate 29 against the housing i8 so that during this 'clock wise rotation, L-he right-hand endjofthe baule.

plate 29 acts as a pivot point and the left-hand end rotates in a clockwise direction to.' uncover the discharge ports. j

Means are provided. for adjustably limiting the upward clockwise movement of the left-hand end of baille plate 29 in order to provide a var iable time delay for the up stroke of the piston. These means are illustrated as comprising a rod 83 passing through holes in the cover plate II f ally. The speed of the upward stroke of the Ipiston i4 will of course depend upon the amount that the baiile plate 29 is moved away from the discharge ports. It it is desired to vary the speed of the upstroke of the piston at any point in the stroke, the adjustable stop 34 may be mounted on one arm of a bell crank 35 which is pivotally mounted in a bracket 36 secured to the cover plate II. 'I'he other arm of the bell crank 35 carries a cam follower 31 which is actuated by s. cam 38 secured to one of the piston push rods I5. The time delay in the up stroke of the piston that is produced by this arrangement depends of course upon the height of the cam 38, and the point in the up stroke at which this variable time delay is introduced depends upon the position of the cam 38 on the push rod I5.

If an automatic variation in the speed of the piston I4 at some point in the stroke is not desired, the adjustable stop may take the form shown in Fig. 4. In this modiiication the stop is shown as comprising a rod 39 screwed through the cover II of the container and projecting through a hole in the piston to a point above the left-hand end of the baille plate 29. The rod 39 may be screwed to leave any desired amount of clearance between the lower end of the rod and the baille plate and may then be locked in position by means o f the lock nut 40.

In order to provide for return ilow of the liquid from the space beneath the piston back through the discharge port so that the piston I4 may be returned by gravity to its lower position, the plate 29 is provided with suitable valve means. These valve means are illustrated as comprising holes or ports 4I in the plate 29 in register with the discharge ports 2| in the pump 'which the 'adjusting rod 33 projects. pump is deenergized, the left-hand end of the housing andsmall plates-V42 slidably mounted on pins 43 whichA are riveted into the plate 29. These plates 42-are held against -the lower side of the plate 29 by means of springs 44. These springs are fairly light so as to allow the plates 42 to be pressed downwardly away fromthe through the discharge ports to the space above the piston. shown, this baille plate is also in`-the form of' a ilattened ring surrounding the central intake of the pump housing 'andis' arranged above the plate 29. It will be understood of course that the positions of the plates 29 and l45 might be interchanged; that lis' Ato say, the plate 45'might be placed in engagement with the jects,-and at a diametrically opposite point la.

housing I8 covering the discharge ports, and' the Aupstroke control baffle plate 29 might .be placed above the plate 45. A hole 46 is provided in the .bailie plate 45.through which the stud 3| prohole 41 is provided in the baille plate through When the baille plate 45 rests o n the bafiie plate 29, whilst the righthand end of the baille plate 45 is held above and away from the ba'ilie plate 29 by means of the adjusting rod 48. lThe rate oi the return flow-of the liquid and the speed of descent of the piston depend upon the amount that the right-hand end o f baffle plate 45 is held above I plate 29. Whenthe pump is energized and liquid under pressure is discharged from the discharge porta-the plateA 45 rises on the stud 3| and onjthe'adjusting rod 33 in response to this pressure, Ithereby allowing the plate 23 to rise and to uncover the discharge ports.

With the foregoing understanding of the elements and their organization inthe completed operator, the operation of the' device itself will readily be understood from 'the following detailed description:

Energization of the -motor I2. vby connection tion of the drive shaftV 24 and the pump impeller I9. Liquid is directed iinto, thefintake passages 20 of the pump impeller by means vof the tubular member 22. This liquid is drawn from the space above thevplston I4 through thcopenings 23 in the tubular member'22, down through the tubular member and into the centrally disposed intake passages 49 and 50 in the pump housing. The impeller forces the liquid outwardly in a radial direction through the dis'- charge ports 2l. as a result of which a Afluid' ,F0 with a source of yelectric power produces a. rot/a-v 45 rises on the adjusting rods 33 and 48 and stud 3|. Liquid is thus discharged from thedmpeller pump to the space beneath the piston I4 and as a result, there is developed across the piston a pressure differential, i. e. a difference in fluid pressure on opposite sides of the piston. This causes the piston to move in an upward direc- 9,21 :,sas

tion, and this pressure and movement are transv mitted through the connecting rods I3 to the external load to which the crosshead I1 is connected.

The speedat which the piston I4 moves during the up stroke depends of course upon the setting of the adjustable stop 34. If the stop is lset for a small clearance between the set screw and the top of the rod 33, the baille plate 23 rises a correspondingly small amount thereby restricting the flow of liquid from the discharge ports and causing the piston I4 to move at a correspond- -ingly reduced speed. For increased clearances between the adjusting screw and the top of the rod 33, the piston will of course move at correspondingly increased speed.

If the stop 34 is mounted on a bell crank as shown in Fig. 3, the piston I4 continues to rise until the cam 33 engages the cam follower 31. Further upward movement of the piston causes the cam follower 31 to ride up on the cam l33 and thus to rotate the arm 35 in a counterclockwise direction 'so as to move the rod 3'3 in a downwardvdirection therebyl decreasing the clearance between the bailile plate 29 and the pump housing I3. The result of this is further to restrict the flow of liquid from the discharge ports and thereby to decrease the speed of the piston.

When the cam 38 passes beyond the follower 31, the speed of the piston is of course restored to its former value. There are many operations and applications in which such a variation in the speed ofthe piston at an intermediate point of the stroke is required.

As long as the motor I2 is maintained energized, the differential uid pressure across the piston I4 is maintained. When the piston reaches the end of its up stroke, this pressure is still maintained and is not increased owing to the fact that the pump is not a positive displacement Dump- Deenergization of the motor I2 stops the pump and the differential fluid pressure across the piston I4 disappears; as a result, the piston descends under the attraction of gravity forcing the liquid back through the discharge openings in the pump housing and thence out through the intake opening and the tubular member 22 to the space above the piston. When the pump stops, the baille plate 29 and the baille plate 45 return to the positions in which they are illustrated in Fig. 1 of the drawing. 'I'he weight of the piston I4 acts through the column of liquid between the lower surface of the piston and the baille plates so as to produce a pressure on the plates 42 of the valve means suiiicient to force these plates 42 downwardly against the compression of the springs 44 to open the valves and allow the liquid to escape back through the discharge ports to the space above the piston by the path previously traced.

The rate at which the piston descends under the attraction of gravity depends of course upon the clearance between the baille plates 29 and 45. As shown in Fig. 1 of the drawing, this clearance is rather small and thus affords a restricted passageway for the liquid as it passes from the space beneath the piston through the valves in the plate 29, and this results in a correspondingly slow downward return stroke of the piston. By turning the adjusting rod 48 to raise the right-hand end of baille plate 45 a greater distance above the plate `29, the clearance is increased and the rate of return flow of the liquid and the rate of descent of the piston are correspondingly increased. Y

It will be noted that the arrangement of the baiile plates 29 and 45 in the communication between the discharge ports of the pump and the lower side of the piston I4 is such that the plate 29 which controls the rate of discharge of liquid from the pump and the speed of the up stroke of the piston does not interfere with the operation of the baille plate 45 which controls the rate of return ilow of the liquid and the rate of descent of the piston, and vice versa, the plate 45 does not interfere with the operation of the plate 29.

Although in accordance with the provisions of the patent statutes this invention `is described as embodied in the best form in which it is now contemplated carrying it into eect, it will be understood that the elements and arrangement shown and described are merely illustrative and that the invention is not limited thereto, since alterations and modifications will readily suggest themselves to persons skilled vin the art without departing from the true spirit of this invention or from the scope of the annexed claims.

What I claim is new and desire to secure by Letters Patent of the United States is:

l. An hydraulic operating device comprising in combination, a liquid container, a piston movably mounted therein, a pump within said container having an intake communicating with the liquid on one side of said piston and a discharge communicating with the space on the other side of said piston, driving means for said pump, a plate member closing the passage between said discharge and said space when said pump is deenergized, means mounting said member to provide for movement of said member to open said passage when said pump is energized thereby to effect movement of said piston, means for adjustably limiting the movement of said member thereby to control the speed of said piston, and check valve means in said plate member registering with said discharge and responsive to deenergization of said pump to provide for return iiow of the liquid through said discharge and return movement of said piston.

2. An hydraulic operating device comprising in combination, a cylinder containing a liquid, a piston movable therein, a pump mounted in the space beneath said piston, means for driving said pump, said pump comprising a rotatable impeller and a housing therefor having an intake communicating with the space above said piston and a plurality of spaced apart discharge ports in the top wall of said housing communicating with the space beneath said piston, a plate member resting on said top wall and covering said ports, said plate member rising in response to liquid pressure when said pump is energized to-uncover said ports thereby to eiect upward movement of said piston, means for adjustably limiting the rising movement of said plate member thereby to control the speed of said piston, and check valves in said plate member registering with said ports to provide for return iiow of liquid through said ports and return downward movement of said piston upon deenergization of said pump and return of said plate member to cover said ports.

3. Anhydraulic operating device comprising a cylinder containing a liquid and provided with a top cover, a piston movable in said cylinder, a centrifugal pump mounted at the bottom of said cylinder immersed in said liquid, said pump comprising an impeller'and a housing therefor having a central tubular intake communicating with the space above said piston and a discharge communicating with the space beneath said piston, an electric motor for driving said pump impeller mounted on said cover and having a shaft extension projecting through said intake to said impeller, an annular plate member surrounding said intake, means mounting said plate member to close the passage between said discharge and the space beneath said piston when said pump impeller `is deenergized and providing for movement oi said member to open said passage when said pump is energized thereby to effect upward movement of said piston, means for adjustably limiting the movement of said member thereby to control the speed of the up stroke of said piston, and spring loaded valve means in said annular member responsive to deenergization of said pump to provide for return flow of said liquid through said discharge and return of said piston in response to gravity.

4. An hydraulic operating device comprising a cylinder containing a liquid and having a cover plate, a piston movable in said cylinder, and having a push rod extending through said cover plate for connection with the work, a centrifugal pump mounted at the bottom of said cylinder, said pump having an impeller and a housing therefor provided with a centrally disposed tubular intake communicating with the space above said piston and with circumferentially disposed discharge ports communicating with the space beneath said piston, an annular plate member surrounding said intake and arranged to close the passage between said ports and the space beneath said piston when said pump is deenergized, and to move to open said passage when said pump is energized thereby to cause said piston to move upwardly in response to iluid pressure, a second rod in contact with said member extending upwardly through said cover and movable in response to movement of said annular member, an adjustable stop for limiting the movement of said rod thereby to control the speed of the up stroke of said piston, and means actuated by said push rod for actuating said second rod to vary the speed of said piston.

5. An hydraulic operating device comprising a cylinder containing a liquid and having a cover plate, a piston movable in said cylinder and having a push rod extending upwardly through said plate for connection with a load, a centrifugal pump immersed in said liquid and arranged at the bottom of said cylinder, said pump comprising an impeller and a housing therefor having a central intake communicating with the space above said piston and circumferentially disposed discharge ports communicating with the space beneath said piston, an electric motor mounted on said cover, and having a shaft extending through said cover to drive said impeller, an annular plate member surrounding said intake and arranged in the passage between said ports and the space beneath said piston so as to move upwardly in response to fluid pressure to open said passage thereby to effect upward movement of said piston, valve means in said member to provide for return flow of liquid through said ports and down stroke of said piston and means for controlling the speed of the up stroke of said piston comprising a second rod projecting through said cover into engagement with said member so as to move vertically in response to movement of said member, a bell crank on said cover carrying an adjustable stop for said rod on one arm and a cam roller on the other arm, and a cam on said push rod for engaging said roller at a predetermined point in the stroke of said piston thereby to adjust said second rod to vary the opening between said ports and said plate.

6. An hydraulic operating device comprising in combination, a cylinder containing a liquid, a piston movable in said cylinder having a push rod extending through said cylinder for connection with a load, means for producing a liquid pressure to move said piston comprising a centrifugal pump and .driving means therefor, said pump comprising an impeller driven by said driving means, and a housing therefor having an intake communicating with the space on one side of said piston and a discharge communicating with the space on the opposite side of said piston, a pair of baille plates arranged in the passage between said discharge and said opposite side of said piston, means mounting said plates to provide for movement of said plates to open said passage in response to uid pressure thereby to eiiect movement of said piston when said pump is energized and in a direction to close said passage when said pump is deenergized, means for adjustably limiting the opening movement of one of said plates thereby to control the speed of the piston in one direction and valve means in said plate to provide for return flow of said liquid through said discharge and return stroke of said piston, the position of the other of said plates serving to control the rate of said return ilow and means for adjustably limiting the closing movement of said other plate thereby to control the speed of said return stroke.

7. An hydraulic operating device comprising in combination, a cylinder containing a iiuid, a piston movable in said cylinder, means for producing a differential in the liquid pressure across said piston to eiect movement thereof comprising a centrifugal pump arranged in said cylinder beneath said piston and driving means therefor, said pump comprising an impeller connected to said driving means and a housing therefor having an intake communicating with the space above said piston and a discharge communicating with the space beneath said piston, means for controlling the speed of the up stroke of said piston comprising a baille plate arranged between said discharge and the lower side of said piston so as to close communication between said discharge and the lower side of said piston when said pump is deenergized and to move to open said communication in response to fluid pressure thereby to effect upward movement of said piston when said pump is energized and means for adjustably limiting said opening movement, valve means in said plate providing for return ilow of said liquid and down return stroke of said piston upon deenergization of said pump, and means for controlling the speed of said down stroke comprising a second baille plate arranged between said discharge and the lower side of said piston so as to move away from said discharge when said pump is energized and to move toward said discharge to restrict said communication upon deenergization of said pump and means for adjustably limiting the movement of said second baille plate toward said discharge to thus vary the restricting eiect.

8. An hydraulic operating device comprising in combination, a cylinder containing a liquid, a piston movable therein, means for producing a differential in the liquid pressure on opposite sides of said piston thereby to eiect movement of said as; 1aos piston comprising acentrifugal pump mounted in the space beneath said piston and vdriving means therefor. said pump comprising an impeller driven by said driving means and a housing therefor having a centrally disposed tubular intake communicating with the space above said piston and a circumferentially dlpsed discharge port communicating with the space beneath said piston, means for controlling the speed oi the up stroke of said piston comprising an annular baille plate surrounding said intake and arranged between said port and the space beneath said piston so as to close the passage between said discharge port and said space beneath said piston when said pump is deenergized and to move upwardly in response to iiuid pressure to open said passage when said pump is energized and means for adiustably limiting said opening movement,

,valve means in said plate providing for return ilow oi liquid through said discharge ports and down stroke of said piston upon deenergization of said pump, and means for controlling the speed o! said down stroke comprisingva second annular banle plate arranged between said discharge port and said space beneath said piston and surrounding said intake and movable away from said discharge port in response to fluid pressure when said pump is energized and movable in a direction to restrict said passage when said punp is deenergized and means foradjustably limiting the movement oi said second bame plate toward said discharge pojt to thus vary the rei3 stricting effect.

. THEODORE W. DRIESCH.

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