US2481991A - Hydraulic circuit - Google Patents

Description

W. ERNST HYDRAULIC CIRCUIT Sept. 13, 1949.

. MW wmwwwwm @Www mm m 2w. m W/ZZ/M WM Filed Nov. 26, 1945 A T TORNIFYS Sept. 13, w ERNST HYDRAULIC CIRCUIT 4 Sheets-Sheet 2 Filed NOV. 26, 1945 INVENTOR WALTER ERNST Sept. 13, 1949. w. ERNST 2,481,991

' HYDRAULIC CIRCUIT Filed Nov. 26, 1945 4 Sheets-Shet z INVENTOR WALT ER E RNST Arr-onus" HYDRAULIC C IRCUIT Filed Nov. 26, 1945 4 Sheets-Sheet 4 lNvB-NTQR WALTER ERNST R'rro IZNEYS Patented Sept. 13, 1949 H-P-M Development Corporation, Wilmington, Del., a corporation of Delaware Application November 26, 1945, Serial No; 630,758

13 Claims.

This invention relates to fluid operable circuits,

and particularly, to fluid operable circuits employing pressure converters for intensifying the pressure in the circuit.

In circuits employing pressure converters or pressure intensifiers it is customary to employ valves for making the pressure converter or intensifier effective or ineffective. The pressures developed by a converter used as an intensifier are usually quite high and difliculty is often experienced in finding valves which will shift freely under the intensified pressures. Tocounteract I the tendency of the valves to stick, it is necessary to manufacture them very heavy and to provide large operating means such as solenoids and large springs in order satisfactorily to shift the heavy valve member.

I Accordingly, it is the primary object of the present invention to provide a method of and apparatus for operating a pressure converter or intensifier which eliminates the necessity for shifting valves under theintensified pressures.-

It is another object to provide an improved method of and apparatus for making a pressure converter and is indicated by the line 2--2' on Figure 3; v

Figure 3 is a transverse vertical section through the converter and is indicated on the line 3-3 on Figure 2; a

Figures 4, 5, 6 and 7 are transverse sections through the converter and-are indicated respectively by lines 4+4, 5-5, 6-45 and l-'! on Fig- Figure 8 is a view of a press operating circuit according to this invention;

Figure 9 is another press operating circuit according to this invention;

Figure 10 is a diagram of an-electrical circuit for controlling the press circuits of Figures 9 Figure 11 is a view of a molding machine employing the principles ofthisinvention; and

Figure 12 is a diagram of an electrical circuit for controllingthe molding press circuit.

General arrangement 7 According to this invention there is a pump whichsupplies fluid'for actuating a motor. Connected between the motor and the pump is a pressure converter .which may be made effective or ineifective. When the converter is inefiective the pump supplies fluid directly to the motorand when the converter is efiective the pump supplies fiuid thereto and the converter supplies fluid at increased pressures to the motor.

The converter or intensifier which it is contemplated using is shown and described in the co-pending applications Serial No. 594,413, filed May 18, 1945, and Serial No. 603,067, filed July 3,

945, now abandoned, both in the name of Warren R. Tucker and assigned to the same assignee as the present application.

This conve'rter'or intensifier includes a valve member which is rotatedby a'motor and is effective only during the time that the motor and valve member are rotating. According to this invention the shift-over to intensifier operation is accomplished by energizing the motor which drives the intensifier valve member. When the motor is de-energized the intensifier becomes ineffective and is bypassed by' suitable conduit means.

In order to synchronize the shift-over to intensifier operation the motor may be energized by pressure responsive means actuated in response to any predetermined stimuli in the circuit.

Referring to Figure ,1, there is diagrammatically illustrated the action of the pressure converter which-is employed in the various hydraulic circuits illustrated in the subsequent views.

In Figure 1 there is apump at In which draws fluid from a reservoir l2 through a conduit [4 and discharges fluid under pressure into the conduit IS. The flow in the conduit I6 is divided in the branch conduits l6 and I6 and enters the chambers l8 and 29 of the pressure converter generally indicated at 22.

The pressure converter 22 comprises cylinder which has a central cylinder within which is reciprocable the piston 26 and the reduced diameter end cylinders within which arereciprocable the pistons or rods 28 and 30. The rod 28 reciprocates in the chamber l8 while the rod 39 reciprocates in the chamber 32. The pitson 2 6 divides the central cylinder into chambers Hand 34.

As mentioned before, the chamber [8 is connected with the conduit [6 andthe chamber 29 with the conduit [6", while the chamber is connected by conduit 36 with exhaust and the chamber 32 is connected by conduit 38 with the inlet of the fluid motor. 40; the motor outlet being connected by conduit 46 with exhaust.

As shown in Figure 1, the pump is supplying fluid to the upper area of the piston 26 and the upper end of the rod 28 while the lower end of the piston 26 is connected with exhaust and the lower end of the rod 30 is connected withthe the motor and with exhaust, a continuous operating system may be had. By further providing a plurality of reciprocating pistons the supply of fluid to the motor 40 may be in continuous and overlapping increments so that per- 1 fectly uniform movement of the motor results.

Pressure and flow converter The intensifier comprises a cylinder block which has a plurality of axial bores 52 circumferentially spaced about a central bore 54. The bores 52 provide cylinders within which reciprocate the pistons 56 having the oppositely extending reduced piston'portions 58 attached thereto. The portions 58 reciprocate in bored cylindrical plugs which are inserted from opposite ends of the I block 50 into somewhat enlarged end portions of the bores 52. The piston 56 and the 'rods 58 define the upper working areas indicated at A and B and the lower working areas indicated at C and D. The working areas are connected by a radial passages with the central bore 54 of the block 50 at different levels.

Within the bore 54 is mounted a valve member indicated at 62 which is supported on the antifriction bearings 54 which has an operating shaft 66 whereby the valve member may be rotated. The block 50 has an inlet port 68 (Figure 3) and the valve member 62 has a groove I0 at the level of the said inlet port. The groove I0 is com municated with the levels of the connections to the areas A and B by a pair of oppositely disposed notches 12 which extend somewhat less than about the periphery of the said valve member.

The levels of the connections to the areas C and D are communicated with the groove I0 by a pair of oppositely disposed notches I4 which are similar to the notches I2 but which are disposed at 90 therefrom.

The valve member comprises the groove I6 at groove I8 is similarly provided with the notches which are disposed at 90 from the notches Arranged at the level of the connection with the area B are the oppositely disposed flats or notches 88 which are disposed at 90 from the notches I2 so that the said notches will alternately communicate with the area B. The notches 88 are connected by radial bores with the central passage 90 in the valve member which communicates directly with an exhaust conduit 92. At the level of the connection with the area C are similarly arranged notches 94 which communicate with the central passage 00 and which are disposed at 90 from the notches 88.

It will be apparent that the rotation of the valve member 62 is effective first to direct fluid from the inlet 68 to the areas C and D while connecting area B to the exhaust 92 and the area A to the outlet 82 and thereafter to reverse the said connections; that is to connect A and B to the inlet pressure, C to exhaust and D to the discharge port. It will also be apparent that by providing a plurality of cylinders and pistons, the same will operate to receive and to discharge fluid in overlapping increments so that substantially continuous operation may be had.

By connecting the motor with the shaft 66 and selectively energizing the motor the intensifier may be made efiective or ineffective as desired. When the intensifier is effective the efiiciency of conversion thereof is high and the energy of the working fluid represented by the production of pressure and volume is substantially the same at the inlet and outlet ports of the converter.

It will be obvious that the drive motor for the valve member could be of any type convenient to employ, such as fluid operable, and need not necessarily be an electric motor as shown.

Circuit of Figure 8 In Figure 8 there is shown a ram I00 having advancing means I02 and retracting means I04 and reciprocable in a cylinder I06. The advancing and retracting means are connected with the service ports of a four-way valve I08 which receives fluid from a conduit H0 and which has an exhaust conduit I I2. The conduit H0 connects with the discharge side of a pump H4 through a check valve IIE opening toward the said valve. The pump I I4 draws fluid from a sump or reservoir through a conduit H8 and expels it at increased pressures to the conduit I I0.

The valve I is continuously urged into position to connect the conduit I I0 with the retracting means I04 by a spring I20 is adapted for being moved into position to connect the conduit I I0 with the advancing means by the energization of a solenoid SI.

The circuit of Figure 8 also includes the intensifier 22 which has its inlet port 68 connected by a conduit I22 with the conduit H0 and its outlet port 32 connected with the advancing means of the ram I00. A motor I24 has its drive shaft connected with the shaft 66 of the intensifier valve member and is adapted for being energized by the closure of the switch I26.

In operation, the solenoid SI may be energized to direct the pump discharge to the advancing means I02 in order rapidly to advance the ram I 06. In response to a predetermined position of the ram, or in response to a predetermined pressure on the said advancing means, or by manual means the switch I26 may be closed to energize the motor I24 to drive the valve member of the intensifier I22. When this takes place the pump supplies fluid through conduit I22 to the intensifier and the intensifier supplies fluid from its outlet port 82 to the advancing means at increased pressure. During the high pressure operation of the ram I00, the check valve H6 blocks oil" the conduit IIO from high presure flow. After the working stroke of the ram I 00, the motor I 24 may be de-energized and the solenoid SI de-energized and the ram retracted to its Figure 8 position.

Circuit of Figure 9 the ram to a halt. 1

The circuit of Figure 9 may also include a makeup check at Mil, a surge valve at I5lJ-1and a main cylinder release and bypassvalveat l 52. Bypassing the check valve at I 3Iiand havinjg its inlet port I58 connected with the inlet side of' the check valve and its outlet port BZ connectedwith the outlet of the check valve is the intensifier unit 22 having the valve member drive otor I24 adapted for being energized by the closure of the switch I26. M

Also connected with the inlet of the cheek I36 is a conduit I54 which leadsto the reservoir I55 and which includes: the check valve I53 opening away from the said reservoir. The purpose of the valve IE8 is to permita supply of fluid to the pump I38 when said pump is delivering int'o the conduit I42. In operation, the ram may bestarted downwardly by energizing the solenoid S2 and shifting the pump I38 to deliver into thepconduit lfl. The rarn'will advance as. rapidly as thepump withdraws fluid from the-retracting means I40 and, upon striking the work, will advance as. rapidly as the pump supplies fluid tothe'advanclng means I32. In response to a predetermined pressureon the said advancing means, or in response, to. apredetermined position. of the said ram;.or,.by.manua1 means the switch I26 may be, closed .toenergize the motor I24 to make the intensifier-efiective. When the intensifier is effectivethe pumpdelivers fluid through the inlet port 68 andthe intensifler delivers fluid at increased.: pressure through its outlet port 82. to the advancing. means I32. During this time, the check valve 136 prevents the high pressure fluidfrom beingtbypassed back to the pump. o M

When the switch I26 is opened and thesolenoid S2 is ale-energized the spring lMshifts the pump to deliver fluid to the retracting means 1 40.; During the retracting movement .ofthe ram I3Ilthe fluid in the advancing means isexpelled through the surge valve I and thepumpdraws fluid from the reservoir through the check valve I58 When the ram is fully retracted it engages the linkage I46 and shifts the pump from retraction stroke to neutral. 7 l

Electrical circuit of Fz'gure lfl I For automatically operating the hydraulic circuit of either Figure 8 or 9 there may be provided a circuit shown in Figure 10.

In Figure 10 there is connected between the power lines LI and L2 the contactor coil A in series with the start switch I60. The start switch It!) is bypassed'by the blades AI of thetcontactor A which provide a holding circuit for the said contactor and which also energizes the solenoid SI or S2 for placing the motor rams on their;

} sponse to a predetermined position of the motor 'r'notor I24:

ram 01' in response to a predetermined pressure on the advancing means thereof. The contactor B has a holding circuit comprising the normally open blades BI which also energize the motor I24. In order to halt the advancing stroke of the ram and-to commence'the' retraction stroke thereof, there is provided a switch I64 which is normally closed and which is operated in response' to a predetermined position of the motor ram or 'in response to a predetermined pressure pn the advancing means thereof. Opening of the switch Ililde-energizesthe contactors Aand B and, therefora the solenoid SI orSZ and the Circuit of Figure 11 In Figure '11 there is shown a molding press :manner wel1-known:,3in.the: art.

"The working area of the booster ram 2-I4and the retraction side rvof the ram r 2 I2 are connected to the service ports of a four-way valve 2 I 6; Pressure fluid is supplied-to the-inlet of the valve2I6 from a pump 2I8 by conduit 220 which includes ascheck valve 222 opening toward theiour way valve. The four-way-valve -also includes an exhaust connection "224 and is continuously urged into position to connect th'e'conduit 220 with the retracting side of theram 2I2 by a-spring-226 and is adapted-tor being moved into-position to connect the conduit 220 with the workingarea of the booster ram by thev energization of a solenoid SIII;

During the rapid advance of the ram 2I2 by the booster ram 2I4, fluid is supplied to the advancing side thereof by aconduit' 228 which includes a check valve 230, the inlet of which is connected with the reservoirand the outlet of 'which is connected with the said advancing side.

During the retracting-movement of the ram 2I2 the advancing side thereof is exhausted through the check valve-230 which is piloted to an open position by fluid conducted thereto through the pilot line 232' from the retracting side of the said ram. 3. g 1 v In Figure 11 the booster 22 ;hasits inlet port 68 connected, with the ;conduit- 220 between the pump 2IB and the check 222 and its outlet port 82 connected with the conduit 228 between the check :valve 230-and the advancing side of the ram 212.. i The motor I24,:-connected ;with the intensifier valve membenais adapted. forbeingenergized by theclosure otafipressure switch 232; which is operated into :its closed position" ;byrpressure;con-

ducted through the pilot line"234 fromtheadvancing side of the motor 2H1. -In order to stabilize the operation of the switch --232-there is connected in series therewith the check valve -236 opening toward the said switch and the adjustablechoke valve 238 in parallel with thesaid check valve. By adjusting the valve 238 the opening of the switch 232 may be delayed'for any predetermined lengthof time r a I i -The injection plunger motor-ZIIlhasits op positeends connected with the service: ports. of

76 the four-way valve 240 which issupplied with fluid '7 from the conduit 242- and which exhausts fluid through a conduit 244; The conduit-242 may be connected with the discharge side of a pump 246 or may receive fluid from the pump 2l8 if desired;

The valve 240 is urged into position to connect the conduit 242 with theretracting side of the motor 219 by a spring 2 58 and is adapted for being shifted into position to connect the conduit 242 with the advancing side of the motor by the energlzation of the solenoid Sl2.

For automatically actuating the valves and for making the intensifier 22 effective there may be provided the electrical control circuit of Figure 12. In Figure 12 there is connected between the power Li L2 a ccntactor coil '3 having the blades Cl which provide a holding circuit for the said coil and which also energize a timer indicated at T. When the timer T is energized it closes the blades Tl solenoid Si and thereby rapidly to close the mold halves 202 and 204. A predetermined time after the blades Tl close, the blades T2 close and energize the solenoid S l 2 to bring about the advancing movement of the plunger 208.

terial and commences to build up pressure the switch 232 will be actuated to energize the motor I24 thereby to make the intensifier effective to deliverhigh pressure to the advancing side of the ram 2E2 to maintain the mold halves tightly clamped together.

The augmented thrust on the mold halves is sufficient to maintain them clamped together against the separating force of the injected molding material and thereby to prevent flash between the mold halves and to insure that the workpieces will be correctly shaped, correctly sized and that they will not require subsequent machining operations.

After a predetermined dwell of the plunger 208, the blades T2 open to de-energize the solenoid Sl2 to permit the retraction of the injection plunger. Due to the choke valve 238 the intensifier will remain in operation for a predetermined time after the retraction of the injection plunger to insure that the material in the mold will have a chance to be set or cured.

After the molding material has set for a sufflcent length of time,the blades Tl open to deenergize the solenoid Sill to permit the retracting movement of the plunger 2| 2. Thereafter, the blades T3 of the timer open and the circuit is ready for a new cycle to be commenced.

It will be apparent that the employment of this invention provides means for securely clamping mold halves together even when the projected area of the cavity thereof is large and the sepwhich the shift-over from one pressure stage to another is substantially instantaneous and eliminates the shifting sures.

While the motor for rotating the valve member has been shown as an electric motor to be actuated in response to the closing of an electric switch by pressure or by the position of the motor ram, it will be apparent that the motor for thereof to energize the When the plunger 208 advances against the molding maof valves under high pres- 8 the valve member could be a fluid operable motor whichwas energized by pressure fluid directed thereto by a valve actuated in response to a predetermined pressure or predetermined position of the motor ram.

It will be understood that this invention is susceptible to modification in order to adopt it to different usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.

I claim:

1. In a hydraulic circuit; a fluid source; a fluid pressure converter having an inlet port connected with said source and also having an outlet'port and an exhaust port, piston means having opposed pairs of working areas thereon in said converter, rotary valve means in said converter movable to connect said inlet port with both of one pair of areas while connecting the others, one with exhaust and one with said outlet port; electric motormeans for driving said valve member to make said converter effective; switch ,valve for bypassing the discharge of said pump around said converter when the latter is ineffeotive.

2. In a hydraulic circuit; a fluid source; a fluid. pressure converter having an inlet connected with said source and also having an outlet and-being operable to receive the discharge of said source and to discharge it from said outlet with the pressure-volume ratio thereof modified, said converter including a rotary valve member which must be driven during the time said converter is to be effective; motor means energizable to drive said valve member; means including a check valve for bypassing the discharge from said source around said converter when the latter is ineffective; and pressure responsive means for energizing said motor to make said converter I effective.

"valve member driving motor means.

4. In a hydraulic circuit; a fluid motor; a reversible fluid source connected to drive said motor in both directions; fluid pressure converting means having its inlet connected with said source and its outlet connected with said motor and operable to receive fluid from said source and to discharge it to said motor with the pressurevolume ratio thereof modified; said converting means including a valve member which prevents fluid flow between the inlet and outlet of the converting means when stationary and makes the converting means effective when driven; motor means connected to drive said valve member; and means responsive to a predetermined pressure acting on said motor for energizing said drive motor.

5. In a hydraulic circuit; a fluid motor; a fluid source; a continuously operable pressure converter connected between said source and motor and comprising a plurality of pistons having double areas on the opposite ends thereof, and

a distribution valve operable to connect both areas on one end of said pistons with said source while connecting the areas at the other ends thereof one with exhaust and one with said motor and moveable to so connect said pistons in sequence; electric motor means energizable to drive said valve member; and pressure responsive means connected with said fluid motor and responsive to a predetermined pressure acting thereon for energizing said electric motor.

6. In a hydraulic circuit; a fluid motor; a fluid source of reversible delivery connected to supply said motor; a fluid pressure converter connected to receive the discharge of said pump and to discharge it at increased pressure and reduced volume to said motor and including a valve member rotatable to make said converter effective; motor means for driving said valve member; means responsive to a predetermined pressure acting on said fluid motor to energize said motor means; valve means bypassing the discharge from said source around said converter when the latter is ineffective; and other means bypassing said converter to permit a supply of make up fluid to said source.

7. In a hydraulic circuit; a reciprocable ram having advancing and retracting means; a fluid source of reversible delivery connected selectively to supply said advancing or said retracting means; a fluid pressure converter connected between said source and said advancing means and operable when effective to modify the pressure-volume ratio of fluid supplied to said advancing means; means responsive to a predetermined pressure acting on said advancing means for making said converter effective; a first check valve bypassing said converter to permit the supply of fluid to said advancing means directly from said source when the converter is ineffective; and a second check valve means bypassing said first check valve means for permitting a supply of fluid to said source when the latter is delivering to said retracting means.

8. In a hydraulic circuit; a fluid motor having a first and a second port; a reversible fluid source connected to deliver directly to said first port or to said second port through a check valve; a reservoir; means connecting said source to said reservoir to permit a supply of fluid from the latter operable motors; means for supplying actuating to either side of the former; a fluid pressure converter bypassing said check valve and adapted for receiving the discharge of said source and for redischarging it at increased pressure and reduced volume and including a rotatable valve member which makes said converter effective when rotated; means responsive to a predetermined pressure at said second port for actuating said valve member; and means responsive to a supply of pressure from said source to said first port for connecting said second port with said reservoir.

9. In a hydraulic circuit; first and second fluid motors; pumping means connected by conduits with fluid to said motors; a check valve in the conduit to one of said motors opening toward the said motor; a fluid pressure converter bypassing said check valve and when inefiective offering no passage to fluid therethrough; and means responsive to a predetermined pressure active on the other of said motors for making said converter effective thereby to increase the pressure of the fluid supply to the said one of said motors.

10. In a hydraulic circuit; first and second fluid to said motors; a fluid pressure converter operable to receive the supply delivered to one of said motors and to redischarge it to said motor at increased pressure; pressure responsive means connected with the other of said motors and operable in response to a predetermined pressure thereon to make said converter effective; and time delay means effective for a predetermined period following the reduction in pressure on said other motor below said predetermined pressure for maintaining said converter in effective operation.

12. In a hydraulic circuit; first and second fluid operable motors; means for supplying actuating fluid to said motors; a fluid pressure converter operable to receive the supply delivered to one of said motors and to redischarge it to said motor at increased pressure; pressure responsive means connected with the other of said motors and operable in response to a predetermined pressure thereon to make said converter effective, and means for maintaining said converter in effective operation for a predetermined period after the pressure acting on said other motor is reduced.

13. In a molding press; a clamping motor and an extrusion motor; means of supplying actuating fluid to said clamping motor and also to said extrusion motor; a fluid pressure converter serially connected with said clamping motor and selectively operable to receive the supply to said clamping motor and to redischarge it to said motor at augmented pressure; and means responsive to a predetermined pressure acting on said extrusion motor for making said converter effective and for maintaining said converter in effective operation for a predetermined period after the predetermined pressure is reduced.

WALTER ERNST.

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

UNITED STATES PATENTS Number Name Date 1,677,860 Ferris July 17, 1928 1,682,776 Crabb Sept. 4, 1928 1,922,513 Wiedmann Aug. 15, 1933 1,930,155 Wiedmann Oct. 10, 1933 1,937,007 Brockel Nov. 28, 1933 1,991,595 Creveling Feb. 19, 1935 2,058,377 Francis Oct. 20, 1936 2,145,956 Stern Feb. 7, 1939 2,185,015 Low Dec. 26, 1939 2,202,140 Burroughs May 28, 1940 2,254,274 Doe Sept. 2, 1941 FOREIGN PATENTS Number Country Date 4,170 Great Britain Feb. 25, 1893

Images