US2276836A - Hydraulic operator - Google Patents

Description

March 17, 1942. E. F. GOETZ HYDRAULIC OPERATOR Filed Feb. 9 1940 1 Inventor: Ernest F. G0 12,

- His Attorney Patented Mar. 17, 1942 HYDRAULIC OPERATOR Ernest F. Goetz, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application February 9, 1940, Serial No. 318,065

6 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 a liquid is utilized to develop a differential in fluid pressure on opposite sides of a piston movably mounted within the cylinder to effect a -movement thereof, 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 fluid pressure when the pump is energized and in which the piston is returned to its initial position by the force of gravity or other means when the pump is deenergized, and a further object of the invention is the provision of-means for controlling the discharge passage between the discharge of the pump and the lower side of the piston to control the speed of the upstroke of the piston. 1

A still further object of the invention is the provision of a bypass from the lower side of the piston to the upper side which is controlled by the same means which controls the discharge passage, thereby to control the time of the return stroke of the piston.

In carrying the invention into effect in one form thereof, a piston is movably mounted in a cylinderwhich contains 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 on one Side of the piston and with a circular discharge port or passage communicating with the space on the other side of the piston. A valve sleeve is provided in the discharge passage. This valve sleeve is arranged to close the discharge passage and toopen the bypass to provide for rapid return of the piston when the pump is deenergized. In addition, means are provided for adiustably limiting the movement of the valve sleeve which opens the discharge passage and for adjustably limiting the movement of this valve sleeve which opens the bypass, thereby to control the speed of the upstroke and the speed of the downstroke of the piston.

For a better and more complete understanding of the invention, reference should now be had to the following specification and to the accompanyin section with certain parts of the operating broken view .in elevation partly in section with the parts of the operating mechanism in the opposite limiting position; and Figs. 3 and 4 are details.

Referring now to the drawing, a cylindrical liquid container to is provided with a cover plate ll upon which an electric motor I2 is vertically mounted. The cover plate II is constructed to provide an integral supporting platform l3 9. short distance beneath the top of the container ill. The cylinder and cover plate may be made of any suitable material such as cast iron.

The cylinder I0 is filled with a suitable fluid medium such, for example, as oil, to a point substantially level with platform l3. A piston H is arranged within the cylinder III for vertical movement, and this vertical movement is transmitted to an external load by means of a pair of connecting rods l5 andl6. The lower ends of these connecting rods are secured by suitable fastening means H to the piston I4, and the upper ends of these connecting rods extend through the cover plate II and are secured to a crosshead l8 which is adapted to be connected to a suitable load. Near the bottom of'the container is an impeller'type pump illustrated as comprising .a housing I! having anouter cup-shaped member l9. and an irmer member-I81). The housing is provided with a circular discharge passage 20. The portions 83 and I91 of the housing are constructed and arranged to provide a chamber-2| within which a centrifugal impeller 22 is mounted for rotation. This impeller is provided with a central intake passage 23.

As shown, the pump housing members I91, and

I9. aresecured by means of suitable fastening means 24, 25 to an impeller housing adapter 26 which, in turn, is secured by fastening means 21 to the lower extremity of a tubular member 28, the upper extremity of which is secured tothe platform '13 by suitable fastening means. Openings 30, spaced apart in the wall of the tubular member 28 are provided to provide communication from the space above the piston H to the intake passage 23 of the pump. It is clear that the wall of the tubular member 28 serve as, a partition means and thus confine the discharge of the pump to the space beneath the piston.

A vertical drive shaft 3i is rotatably mounted in a bearing 32 in platform I 3 and in a double sealed bearing 33 which is centrally mounted in the lower portion I9a of the pump housing. This drive shaft 3| is connected to the motor shaft 34 by. suitable coupling means 35 so that rotation mechanism in one limiting position, Fig. 2 is a '55 of the motor produces rotation of the impeller 22,

For the purpose of controlling the speed of the upand downstrokes of the piston, a valve sleeve 36 is slidably mounted in the circular discharge passage 20. The sleeve is provided with rib members 31 which are secured by suitable fastening means illustrated as studs 36, 39 to a yoke 40. A cover pipe 4| surrounds the shaft 3| and is secured to the platform I3 by means of a flange 42 which is bolted or otherwise secured to platform l3. Yoke 40 has a central portion 40- which is bored out and is slidably mounted on the cover pipe 4|.

The cover pipe 4| is provided with a shoulder 4|; against which a steel ring 43 bears. Crosspiece 31 of the valve sleeve 36 is provided with a circular raised portion 31. which provides a recess for the end of a spring 45.

A lever member 46, which comprises two side arms 56s and 46b and a P13138460 connecting the two arms, is pivoted to two depending lugs 41 and 48 which are formed integral with platform l3. Lever mechanism 66 is provided with pins 46 which slide in slots 49 .and 50 in the central portion 40.; of yoke 40 and thus provide for movement of lever 46 about its pivots in response to movement of the valve sleeve 315.

For the purpose of adjustably limiting the upward and downward movements of the valve sleeve 36, a pair of adjusting screws 52 are provided which pass through the cover plate II and extend to positions in which they cooperate with the lever mechanism 46. Screw 52 may be screwed to a desired position above the connecting plate 66 of the lever mechanism 66 in which it limits the downward movement of valve sleeve 36. The connecting plate 46a is cut away to provide a passage 53 through which adjusting screw 5| extends. Screw 5| may be screwed to a desired position below the connecting plate 460 so that the upward movement of the valve sleeve 36 may be limited as desired when the lever mechanism comes in contact with the nut 54 on the lower end of screw 5|. The speed of the upward stroke of the piston M will of course depend upon the amount of opening of discharge passage provided by the upward movement of valve sleeve 36. Thus it will be seen that by adlusting the screw 5|, the opening of the discharge passage 20 from the pump can be varied and thereby the time required for the upstroke of the piston varied as desired.

The upper circular edge of pump housing member I9 is separated from the lower edge of the housing adapter 26, and thus provided for a bypass from one side of the piston to the other which is independent of the passage through the impeller chamber of the pump. When the upper edge of valve sleeve 36 is below the lower edge of housing adapter 26, the bypass isopen, as

shown in Fig. 1, and when the valve sleeve 36' overlaps the lower edge of adapter 26, as illustrated in Fig. 2, the bypass is closed. The speed of the downstroke of the piston l4 and therefore the time required for the stroke to be completed will depend upon the amount of opening of the bypass, i. e., the amount of openingbetween the lower edge of housing adapter 26 and the upper edge of valve sleeve 36. Thus it will be seen that by varying the adjustment of screw 52, the opening of the bypass can be varied and thereby the time required for the downstroke of the piston can be varied as desired. The container I0 is filled with a liquid, such as oil, up to the level of platform 83. Assuming that the screw 52 is adjusted to provide maximum opening of the pass.

bypass, the valve sleeve 36 will be in the position illustrated in Fig. 1.

With the foregoing understanding of the elements and their organization, the operation of the device itself will readily be understood from the following detailed description.

Energization of the motor l2 by connection with a source of electric power produces a rotatlon of the impeller drive shaft 3| and the pump impeller 22. Oil is drawn from the space beneath the piston I4 through the bypass between the valve sleeve 36 and housing adapter 26 and into the central intake passage 23 of the pump. Oil is also directed into the intake passage 23 by the tubular member 28. This oil is drawn from the space above the piston I4 through the openings 3.0, down through the tubular member and into the centrally disposed intake passage 23. The impeller forces the oil radially outward through the impeller chamber and through orifices in housing member l9, into the circular discharge passage iil, as a result of which a fluid pressure is produced against the lower surface of valve sleeve 36 of suificient magnitude to raise the valve sleeve 36 to a position in which the lower edge of the valve sleeve is above the upper edge of housing member I98.

Th loading of spring 45 is such that theimpeller must come up to full speed and develop a predetermined oil pressure in order to move the valve sleeve and thereby open the discharge passage from the pump housing and close the by- Thus this part of the operating cycle, i. e., the starting time for movement of the piston is independent of the external load on the piston and is therefore uniform for all loads.

Atfer the discharge passage opens (the bypass being now closed), there is developed across the piston a pressure difierential, i. e., a difference in fiuid pressure on opposite sides of the piston. This pressure differential causes the valve sleeve 36 to move to an intermediate position in which the opening of the discharge passage and the fluid pressure differential across the piston is dependent upon the external load. That is to say, when the external load is heavy, the valve sleeve will be in a position to produce a correspondingly large opening of the discharge passage, and when the external load is light, the valve sleeve will be in a position in which the opening of the discharge passage is correspondingly-small. In other words, the pressure for moving the piston is roughly proportional to the external load on the piston, and thus the time required for the upstroke is substantially uniform for a wide range of loads.

As soon as the piston has completed its stroke, the oil pressure will reach its maximum and the valve sleeve 36 will complete its travel to the limit imposed by the adjustment screw 5| as illustrated in Fig. 2.-

The return stroke is initiated in response to deenergization of the motor. As a result of this the impeller slows down, and the oil pressure differential decreases rapidly. When the oil pressure decreases but a slight amount, the spring 45 forces the valve sleeve down thus shutting off the oil flow through the impeller chamber and the discharge passage, and opening the bypass so that oil flows from the space beneath the piston through the bypass into the tubularmember 28 and out through the openings 30 into the space above the piston. It will be noted that the time required for the piston to start down is independent of the external load. The downstroke principle, it will be understood that the elements and arrangements 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 ing in combination, a fluid container, a piston.

mounted in said container for relative movement with respect thereto, an impeller housing mounts.

ed in said container having an impeller chamber, an annular shaped discharge passage surrounding said chamber and leading from said chamber to the space on one side of said x piston, and anintake passage in said housing leading toward the space on the other side of said piston, conduit in response t ideenergization of said driving means, and adjusting means for limiting the movement of said sleeve to open said discharge passage thereby to control the time of movement of the piston in one direction.

3. An hydraulic operating device comprising n combination, a fluid container, a piston movably mounted therein, an impeller housing having an impeller chamber, an intake passage leading from said chamber to the space on one'side of said piston and a discharge passage leading from said chamber to the space on the opposite side of said piston, an impeller in said chamber,

, meansfor driving said impeller thereby to proing means, and adjusting means for variably lirn- I means leading from the space on said other side sponse to pressure produced by rotation of said' impeller to provide a confined communication from said intake passage in said housing to said open end of said conduit means, close said bypass and open said discharge passage thereby to apply a diiferentlal pressure to said piston to effectmovement thereof, and biasing means for moving said sleeve to open said bypass and close said discharge to eiTect quick return of said piston in response to deenergization of said impeller.

2. An hydraulic operating device comprising in combination, a fluid container, a piston movably mounted therein, an impeller housing'having an im eller chamber, an'intake passage leading from said chamber to the space on one side of said piston and a discharge passage leading from said chamber to'the space on the opposite side of said piston, an, impeller in said chamber, means for driving said, impeller thereby to produce a differential fluid pressure on said piston for efiecting movement'thereof, means providing.

a quick release passage from one side of said piston to. the other independent of the passage through said impeller chamber, a valve sleeve arranged in said discharge passage, means biasing said valve sleeve to cut off said discharge passage, said sleeve being movable in response to energizat'on of said driving means to open said discharge passage and to close said quick release passage and said biasing means serving to move said valve sleeve to open said quick releage passage and to close said discharge passage duce a diiferential fluid pressure on said piston for effectin movement thereof, means providing a quick release passage from one side of said piston to the other independent of the passage through said impeller chamber, a valve sleeve arranged in said discharge passage, means bias-' ing said valve sleeve to cut oij said discharge passage, said sleeve being movable in response to energization of said drivin means to open said discharge passage and to close said quick release passage and said biasing means servi to move said valve sleeve to open said quick release passage and to close said discharge passage in response to deenergization of said driviting the movements of said sleeve to open said quick release passage and to open said discharge passage to control the time of the work and return strokes of said piston. v

4. An hydraulic operating device comprising in combination, a fluid container, a piston mounted for movement in said container, an impeller housing mounted within said container and immersed in the fluid therein, said housing being provided with an impeller chamber, an intake passage leading from said chamber to the space above the piston and a discharge passage leading from said chamber to the space beneath the iston, means providing a quick release passage from the space beneath said piston to the space above said piston independent of the passage through said impeller chamber, an impeller within said housing and means for driving saidimpeller to produce a differential fluid pressure on said piston for effectin movement thereof, a valve sleeve arranged in said discharge passage so as to be responsive to energization of said impeller to open said discharge passage and close said quick return passage, biasing means for actuating said sleeve to open said quick return passage and close said discharge passage in response to-deenergization of said impeller, and means for adjustably limiting the movements of said sleeve to open said discharge passage and to open said quick return passage thereby to control the time of the upand downstrokes of said piston.

5: An hydraulic operating mechanism comprising 1,1 combination, a fluid container, a piston movably mounted therein, an impeller housing mounted in'said container immersed in the fluid contained therein and having an impeller chamber, a discharge passage'leading from said impeller chamber to the space on one side of said piston and an intake passage leading from said chamber toward the other side of said piston, a tubular member disposed within said container passing through said piston and providing a pasa differential fluid pressure for moving said piston, means providing a byp ss from said'tubular member about said impeller chamber to said first mentioned space on said first mentioned side of said piston, a valve sleeve in said discharge passage responsive to pressure due to the rotation of said impeller to open said discharge passage and close said bypass thereby to-apply a diflerential pressure to said piston to efiect movement thereof, and biasing means for moving said sleeve to open said by-pass and close said discharge to effect quick return of said piston in response to deenergization of said impeller.

6. An hydraulic operating mechanism comprising in combination, a fluid container, a piston movably m unted therein and having a rod extendin through said container for connection with a load, an impeller housing mounted in said container immersed in the fluid therein and having animpeller chamber, said housing havinga, central inlet and a, circular discharge passage leadingirom said chamber to the space on one side of said piston, a tubular member extending from said inlet through said piston to provide an intake passage leading to the space on the other side of said piston, an impeller in said impeller housing, means for driving said impeller comprising a drive shaft extending through said tubular member to said impeller, a valve sleeve in saiddischarge passage, a spring surrounding said drive shaft biasing said valve sleeve to close said discharge passage, a bypass leading from one side of said piston to the other independently of the passage through said impeller chamber, said impeller serving when rotated to produce a fluid pressure to move said sleeve to open said discharge passage and close said bypass and to produce a differential fluid pressure on opposite sides of said piston to efiect move ment thereof, said diflerential pressure being proportional to the load on said piston so that the opening of said discharge passage is also proportional to the load on said piston and the time for the complete upstroke of the piston is substantially the same for a Wide rangeof piston loads, said biasing spring serving to return said valve sleeve to its closed position thereby to open said bypass to effect quick return of said piston upon a drop in pressure due to the stopping of said impeller.

ERNEST F. GOETZ.

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