US2260175A - Press with electrically controlled collapsible air link - Google Patents

Description

Oct 21, 1 w. ERNST EI'AL PRESS WITH ELECTRICALIIY CONTROLLED COLLAPSIBLE AIR LINK Filed Jan. '25; 1940 s Sheets-Sheet 1 J N i rr-- g ,4 2 a o O a M N 3 g 3 n s o H 14 3 0 4| 5 5 s L1 3 5: 3x t g d l 0 I0 m #9 L 2 .T' J c :5

d" m 4 0') V a I 5 Inventors I H WALTER ERNST VICTOR 5.5mm HERBERT 5. BOOHER b PauL C. Pococx mini;

. Auornmya Oct. 21, 1941. w. ERNST ETAL 2,260,175

PRESS WITH ELECTRICALLY CONTROLLED COLLAPSIBLE AIR LINK Filed Jan. 25, 1940 I5 SheetsSh eet 2 Jena Foam I Lab 1.2.2.

lnvzntors WRLTER ERNST .85 VlCTOR 5. SHAW HERBERTiBuuHER PAUL LPOCOUA Mlornzys Oct. .21, 1941. w. ERNST ETAL 2,260,175

PRES S WITH ELECTRICALLY CONTROLLED COLLAPSIBLE AIRLINK Filed Jan. 23, 1940 3 Sheets-Sheet 5 111mm WALTER ERN VICTOR 3. SHAW, HERBERT $.BO0HER, PAUL C.POCOCK,

av m CIA/101M045,

. inoperative to alter a collapsible switch operated by the ram at a Patent ed Oct. 21, 1941 um'rso STAT Es PATENT orrlcs rrmss wrrn smc'rmcmr comonmn COLLAPSIBLE LINK Walter Ernst,

and Herbert 8. Booher,

aslignors to The Hydraulic poration, Inc.,-' W of Delaware Application January 2 11 Claims.

This invention relates to hydraulic press control systems, and in particular, to systems for selectively .varyinglthe speed of travel of the ram at different portions of its stroke.

One object of this invention is to provide a hydraulic press'control system with a press sup- Victor s. Shaw, Paul 0. Pocock,

Mount Gilead, Ohio,

Development Cor- DeL, a corporation 3, 1949, Serial No. 315,204

. control system, as set forth in the preceding obplied with'pressure fluid from a source regulated predetermined point in the stroke of the ram to Jects, wherein the collapsible link is operated by pressure fluid, such ascompressed air, and is provided with an adjustable stop for regulating the extent of slow-down of the ram by adjusting the distance through which the link can 001- lapse and expand. 1

In the drawings: z y

Figure-1 is a diagrammatic view, partly insection, of a hydraulic press control system with a collapsible linkcircuit arranged according to one embodiment of the invention.

Figure 2 is a wiring diagram of the electrical circuit for controlling the main solenoid and permit the pump flow-control member to shift to a reduced delivery position so as to slow up the ram for a portion of its stroke in one direction, means being provided for rendering the link the pump flow during the ram stroke in the opposite direction.

Another object is to provide a hydraulic control system having a press with a ram operated by pressure fluid from a variable delivery pump, link being provided between the and the pump flow-control being controlled by a solepress control rod member, this link -noidal valve in circuit with the main solenoid which operates the pump control so' that the solenoidal valve is incapable of energizationwhile the main solenoid is deenergized, thereby preventing the accidental collapsing of the link during the return stroke of the ram.

valve-operating solenoid-oi the collapsible link circuit. I v

Figure 3 is a longitudinal section 7 through the collapsible link according to this invention, showing the adjustable stop arr ngement.

Figure 4 is an' enlarged pers tive view of .the cam forproviding a dwell during the press slowdown period. v

Figure 5 is a diagrammatic view similar to that of Figure 1 but comprising means for reversing the travelof the press platen in response to a predetermined position thereof.

Figure 6 is a wiring diagram pertaining to the structure of Figure 5.

In general, the hydraulic press control system of the present invention consists of a press having a ram which is reciprocable by pressure fluid supplied by a variable delivery pump, the flowcontrol member of which is actuated in at least Another object is to provide a hydraulic press control system with a ram reciprocable by pressure fluid supplied from a variable delivery pump, the mechanism between the ram and the flow-- control member of the pump including a collapsible link under the controlof a solenoidally operated valve, the valve solenoid being in circuit with the main solenoid for operating the pump control,- and additionally controlled by a limit predetermined location in its stroke.

to provide a hydraulic press Another object is control system as set. forth in the preceding obiect, wherein the limit switch is actuated bya cam having a dwell portion for controlling the duration of the slow-down period ofthe ram.

Another obict'is to provide a hydraulic press .one direction by a main solenoid. Connected between the main solenoid and the flow-control member of the pumpis a collapsible link operated by pressure fluid, such as compressed air, and under the control of a solenoidally operated valve, the valve solenoid in turn, being under the control of a limit switch operated by the ram at a predetermined location in its stroke. The valve solenoid is arranged in the same electrical circuitwith the main solenoid sothat it cannot be flow and an undesired continuation of the travel energized except when the main solenoid is energized.

This feature prevents the'accidental collapsing of the link during the return stroke of the ram which has hitherto occurred as the ram approaches its neutral position and shifts the pump control to neutral. Hitherto, the accidental collapsing of the link as the pump control appreached neutral caused a sudden resumption of of l the ram instead of a halting thereof. This undesired travel 0! the ram past its halting posi- 2,184,665, of'December. 26, 1939. Pivotaliy eon-L tion has previously caused damage tothe press, stripping collars and pins from the press control rod and breaking the control linkage, or other mechanism, and causing other damage by reason 01' the fact that the pump control has not moved to its neutral position as intended.

The present invention prevents this accidental 1 collapsing, and also provides a control over the duration of time the link is collapsed by actuating the limit switch of the solenoidal valve by a cam having a dwell portion thereon. Another feature of the invention is the provision of an adjustable stop. within the collapsible link, this adjustable stop being arranged to control the 3 distance through which the link collapses and consequently thedistance through which the pump flow-control member moves in reducing its delivery.

Referring to the drawings in detail, Figure 1 shows a press I0, hydraulically connected to the .opposite side being connected to the coma reversible variable delivery pump H and having a collapsible air link i2 interposed between the pump control and the main solenoid l3 which operates the pump control and is connected to the press control mechanism. Also 5' provided in the press circuit is a pilot pump l4 1 o n ted to supply pressure fluid to the servomotor li. for shifting the flow-control member g of. the pump II. The hydraulic circuit also con- 1 tains a main cylinder release and by-pass valve 1 16 of the type disclosed and claimed in the Ernst Patent No. 1,956,758 of May 1, 1934, and

I forming no part of the present invention. Ad-

jacent the valve I5 is a surge valve l1 of the 1 type disclosed and claimed in the Ernst Patent N0. 1,892,568 of December 27, 1932, and likewise I forming no part of the present invention.

f A tonnage control or pressure-responsive 3 electrical limit switch 13 is likewise provided f for regulating the pressure at which the press Ill is reversed and caused to perform a retraction stroke. Pressure reliet valves I9, 20 and 2| and 1 a check valve 22 are provided in the remaining portion of the hydrauliccircuit. A solenoidally .operated valve 23, controlledby a limit switch 24, is provided in the pneumatic circuit controlling the collapsible link the compressed air ,supplied therefor being additionally regulated by a manually operated needle valve 25. The

pump II is likewise provided with a safety cen- 1tering device 26, of known design, on the op-' positeside of the pump II from the servomotor iii, and its details form. no part of the present invention. Y

The press II- is provided with a main cylinder 33 having a main plunger 3| reciprocable therein, and connected to a main ram'or platen 32 having a platen arm 33 projecting laterally therefrom. The press I. likewise has a reciprocable control rod 34 wltha collar 35 engage- 6o able by the platen arm 33 at a predetermined position on its return stroke, and a collar 33 for actuating the pump control mechanism as hereinafter explained.- A retaining collar .31 at the top of the control 34 regulates the distance 65 through which the latter descends. The platen arm 33 on its outer end is provided with a bracket 33 carrying a cam 33 for operating the limit switch 24.

g'lheservomotorllwhichahiftstheshlftr ns 70 or flow-control member of the reversible variabio delivery pump is under the control of a servomotor control valve rod-.43, irrthemanner Set 10111: in the Irnat application Ser. N0. 170,- 2'0, flied 0830b :1. 1m.

nected at 4| to the servomotor control valve rod 40 is a rocking lever 42, having its fulcrum at 43 and pivotally connected at its opposite end to the pin 44 engaging the arm 45 on the cylinder 46 of the collapsible air link l2. The plunger 41 of the latter is pivotally connected, as at 48, to the rocking lever 49 having its fulcrum at 50 and pivotally connected at ii. to the ,link 52. The latter is pivotally connected at 53 to the arm 54, mounted upon the shaft 55 upon which the rocking lever 56 is also mounted. One end of the rocking lever 56 is provided with a rounded yoke engageable by the collar 36 as the press pressed air supply conduit 59. Also connected .to

the conduit 58 is thebranch conduit 60 running to one side of the solenoidal valve 23, the opposite side thereof being connected to the air exhaust conduit 6i. The solenoidal valve 23 is operated by a solenoid 62 in circuit with the limit switch 24, as hereinafter'explained.

The cam 39 on the bracket 38 (Figure 4) may be made in a single piece, or-it may consist of three pieces 63, 64 and 65 clampedto the bracket 38. The portions 63 and 65 are beveled and provide the entering and leaving portions of the cam 39, whereas the portion 64 is a dwell portion, the length of which regulates the duration of the slow-down period. These three portions are clamped to the bracket 38 by the screws 86,-

61 and 68, respectively. By loosening the screws 66, 51 and 58 the dwell portion 64 may be removed and a longer or shorter dwell portion substituted. The limit switch 24 is provided with a contact arm 69 for engagement with the cam 39. T

The collapsible air link l2, as previously stated,

consists of a cylinder 46 having a projecting arm against an annular enlargement 16. The plunger 41 passes through a hollow plug 11, threaded as at 18 into the cylinder 4' and provided internally witha bored plug 13 for retaining an annular oil seal element-3| in position. 0n the plunger 41 there is also mounted a stop collar 3|, secured thereto by the set screw 32.. This stop collar engages the inner end wall of the cap 10 when the piston 13 moves to its extreme left-hand position. If,-however, the cap III is unscrewed a sufllcient distance the piston 13 will be halted by the annular stop portion 33 on the inner end of the plug 11. The cylinder 46 is provided with threaded and ports 34 and 33. The port serves to receive' the end of the conduit 53, whereas the port 33 receives a threaded plug 33, preferably with a drilled passageway therethrough (not shown) as a The right hand end of the cylinder 43 is provided with an annular-ridge l1 88171118 new Patent, No. 16 tonl3.

- the automatic restarting switch I06 in the hydraulic'circuit, in addition to the elements previously mentioned, the pump II is connected by the conduits 88 and 89 to the upper and lower ports 90 and 9I of the main cylinder I0.

A branch conduit 92 runs from the conduit 89 to the main cylinder release and by-pass valve I6. from which the conduit 93 runs to the port 94 in the upper end of the main cylinder I0. A branch conduit 95 also runs to the surge valve I1 to open the latter upon the return stroke of the press. The pilot pump I4 receives fluid fromthe surge tank 96 through the conduit 91, and discharges pressure fluid through the conduits 98 and 99 into the servomotor I5. The branch conduits I and IN run from the endsof the servo- I motor I6 to the surge tank 86, and the exhaust conduit I02 runs to the surge tank from the pressure relief valve 2 I. The pressure-responsive tonnage control limit switch I8 is connected by the conduit I03 to the port I04 in the upper end of the main cylinder I0, and is also provided with an exhaust conduit I05 running to the surge tank 96.

forming a holding circuit for the operating coil II5 when the push-button switch III is released after being momentarily depressed. The valve solenoid 62 contains an armature 63" for operating the solenoidal valve 23.

The electrical control circuit (Figure 2) is energized from the main powerlines I20 and I2I' through the branch lines I22 and I23. One of the semi-automatic contacts of the combined push-button. and selector switch I08 is connected to one contact of the push-button switch III by the line I24, from the other contact of which the lines I25 and I26 run to the automatic restarting switch I06 and interlock contact of the magnetic contactor II4, from the other contact of The electrical circuit, in addition to the main solenoid I3, the valve solenoid 62, the limit switch 24 andthe tonnage control limit switch I8, also contains a normally open automatic restarting switch I06 (Figure 2) operated by the platen as it nears the end of its return stroke and before the control rod 34 has been raised a suflicient amount to shift the pump control to its neutral delivery position. The restarting switch I06 is ordinarily actuated by the control rod 34 and may be shifted by its engagement with the collar 31, or any other suitably located stop. As shown in Figure 1, the restarting switch I06 is mounted upon the bracket I01 which serves as a guide for the upper end of the control rod 34, but it may likewise be mounted in any other suitable position. The automatic restarting switch I06 serves to automatically reenergize the main solenoid I3 and place the pump I automatically upon its forward delivery stroke as the plunger 3I nears the end of its return stroke. This feature enables the press to be operated in so-called full automatic operation, wherein the plunger 3| and ram or platen 32 perform a-repeated number of working and return strokes without halting more than momentarily at the end of each stroke.

when semi-automatic operation is desired so single working stroke stroke and then halts, is switched out of the circuit by the combined push-button and selector switch I08. -An additional switch I09 of this combined type is provided for selecting whether automatic operation or hand operation is to be employed, and is also used in its pushbutton function for manually reversing-the press at any point in its cycle. Hand operation is employed when the electrical control circuit of Figure 2 is deenergized and the press control rod 34 is raised manually by a hand lever (not shown).

The electrical that the press performs 2. followed by a single return circuit likewise contains an oil temperature limit switch IIO (Figure 2) whichis shifted from its normally closed position to a circuit-breaking position by a thermostat when the temperatureof the oil, or other working fluid, exceeds a predetermined maximum. The opening of the oil temperature limit switch I I0 terminates the automatic operation of the press. An additional forward push-button switch III is likewise provided as a safety feature, so that the operator must use both hands in starting the press.

order to indicate when the electrical circuit is enwhich the line I21 runs to the tonnage limit switch I8. From the latter the line I28 runs to the combined push-button and selector switch I08, as does the line I29 from the automatic restarting switch I'06. The tonnage limit switch I8 is connected by the line I30 to the operating coil II5 of the magnetic contactor II4, from the other end of which-the line I3I runs to the combined push-button and selector switch I09. Be-

yond this the line I32 runs to the signal light II2, from which the lines I33, I34 and I35 run to the branch power. line I23 by way of the resistance II3. From the branch power line I22 the line I36 runs to the oil temperature limit switch IIO, beyond which the line I31 runs to the combined push-button and selector switch I09. The valve solenoid 62 is'connected by the line I38 to the branch power line I23, and by the line I39=to the platen-operated limit switch 24, beyond'which the line I40 runs to one of the contacts of the contactor switch blade H8. The line I4I runs from the same contact to the main solenoid I3, from which the line I42 runs to one contact of the contactor switch blade II1.

It will be noted that on the return stroke of .the press ram the servo-motor on the pump is includes the air link 46 moves the servo-motor. control rod 40 to place the pump on neutral.

Withoutair pressure in the air link 46 no movement can be transmitted through the linkage and, therefore, the pump remains at full stroke tending to force the ram beyond its upper limit, with the corresponding damage to control linkage.

In Figure 1 it will be noted that an air cylinder I43 is in connection with the pipe 59. In this cylinder is a piston I44 and a piston rod I'45. The piston is spring pressed upwardly by spring I46, the lower end of piston rod I45 engages the roller I41 of the switch arm I48 of the switch I49 which controls the circuit included within the wires I50 and I5I. The wire I50 is connected .to a terminal I52 which is adapted to be engaged by the motor starting switch I53.-- The other side of the terminal I52 is connected v to a wire I54 to the terminal I55. This is a part of a holding circuit which consists of'the wire I2I, wire I56, terminal I51, blade I58 to the 'wire i 32. nished to the compressed air supply line 69 and ,flowsthrough the needlevalve 26 and the conduit 66, into the left-hand end of the collapsible of which is connected to the main line wire I20 and the other side of which is connected by the,

wire I62 to the terminal I63 engaged by the v motor stop switch I64, the other side of which is connected to the terminal I66 and, wire I6I,

' which is in turn controlled by the switch I69- Returning to the "switch arm I59, the lines I20, I2I. and I2Ia are connected to the motor 10 lines I66, I61 and I68 of the motor I69 by the A switch blades I10, HI and I12.

' In operation the switch I49 is normally closed by the air pressure in the line 69. r In the event of failure of that air pressure, the spring 615 will move up the piston rod I45 permitting the switch I49 to open under the influence of a spring I49a. The air pressure acts against the spring pressure or spring I46 to hold'the plunger at full stroke position. With the, plunger air operated as above, the limit switch I49 in series with the stop button I64 for themain motor circuit will be held closed. On the failure of the ai or loss of 'air pressure, the spring I46 will ret the plunger I I46 to. its opposite position allowin gle '25 closed limit switch I49 to open to press the ed a trol circuit to the motor I69 in the same manner\ as when the stop button I64 is pushed.

Operation In the operation of the press control circuit of this invention the pumps II and I4 are first started in operation. To cause the ram 32 to execute a working stroke, the operator momentarily depressesthe switches I06 and III. If 35 semi-automatic operation is desired the switch I08 is locked in engagement with thelower or semi-automatic contacts. Under thesecircumstances the contactor coil H6 is energized from the branch power line I23 by way of the lines I36 and I26, the push-button switch II I; the line I24," the switch I06, the lines I28 and I30, the contactor winding II6, the line I'3I, the switch I09 (assuming, of course, that it is set for automatic' operation), the line I31, the oil temperature limit switch I16 and the line I36 to the branch power line I22.

The normally open magnetic contactor H4 then closes so that its switch blades H1 and H6 energize the main solenoid I3. -The interlock switch blade H9, in closing, operates a holding circuit which maintains the energization of the 1 magnetic contactor winding -I'I6 even when the forward push-button switch I is released. The

energization of this holding circuit is maintained 55.

from the branch power line I23, through the line I36, the now closed switch blade N8, the line I21, the tonnage control limit switch I8, the line I38, the contactor winding II6, the line I3I, the switch I69, the line I31, the oil temperature no limit switch H0 and the line I36 to the branch power line I'22. The valve solenoid 62, however,

as yet remains 'unenergized since the normally open limit switch 24 has not yet closed by reason of the descent-of the platen or main ram Meanwhile compressed air has been furair link I2. This compressed air pushes the pis- 7 ton head 13 to the right, shortening the distance 0 between the 1 pivotpins' and 46. noidal valve 23, however, remains in its normally closed position since its solenoid 62 has not yet 4 been energized.

The soleeans The energization of the main solenoid I3, as

described above, pullsdown its armaturel61 and rocks the rock shafts 56 and 49 (Figure 1), shifting the collapsible link I2 to the left and rocking the lever 42 to-cause the servomotor control valve rod 40 to move to the right towards the servomotor I5. This action shifts the shift ring or flow-control member of the variable delivery pump II and places the latter on stroke so that it delivers pressure fluid by the conduit 66 to the upper endof the main cylinder I0, and withdraws fluid from the lower end thereof throughthe conduit 89. The consequent descent of the main plunger 3|. and ram 32 causes the cam 38 to engage the contact member 69 of the limit switch 24 so that the latter is closed and energlzes the valve solenoid 62 since the latter is .electrically connected through the lines I36 and I40 to the already energized main solenoid I3. The solenoidal valve 23 then opens, permitting compressed air to escape through the conduits 68 and from the left-hand end of the collapsible link cylinder 46. the cylinder 48 then move relatively to one another so as to increase the distance between'the pivot pins .48 and 44. This permits the servomotor control valve rod 40 to shift toward its reduced delivery posiiton, moving the shift ring of the pump II toward its reduced delivery position and consequently slowing down; the speed of the main plunger 3I and main ram or platen 32.

Meanwhile, the main ram 32 continues to descend, and the contact member 69 'of the limit .switch 24\ rides along the dwell portion 64 until it arrives. "at the beveled portion 63, when it is permitted to swing back to its normally open position. The opemng of the switch 24 deen-. ergizes the valve solenoid 62 and closes the solenoidal valve 23. Air from the air supply conduit 69 then passes through the needle valve 26 and replenishes the air in the left-hand end of the cylinder 46, causing the pistons 13 and cylinder 46 to'move again into their contracted position with the pivot pins 44 and 48 at their minimum separations. i

The consequent shifting of the servomotor control valve rod-immediately shifts the pump shift ring or flow-control member toward an increased delivery position, increasing the discharge of pressure fluid'to the main cylinder I6 and speeding up the descent of the main ram 32. The latter then completes its working stroke. whereupon the building. up of pressurein the main cylinder I 0 by engagement of the main ram 32 with the workpiece, causes the normally closed tonnage control limit switch I6 to open, breaking the holding circuit of the magnetic contactor coil II6 by opening the circuit between the lines In and I30-(Figure 2).

The opening of the magnetic contactor II4 immediately deenergizes the main solenoid I3;

whereupon a spring (not shown) within the servomotor I6 shifts the servomotor control valve rod 40 to its reversed delivery position. The

variable delivery pump II then delivers pressure; fluid through the conduit 69 to the lower end of the main cylinder I0, and exhausts fluid from the upper end through the conduit 86. The main cylinder release and by-pass valve I6 operby-Dass the iiow'of the pump ates to momentarily while releasing pressure fluid from the upper end of the main cylinder I6 at the instant of reversal, as described in'the previously mentioned p atent disclosing and claiming this device; at

The piston head 13 and the same time the surge valve I1 is forcibly opened, as described in the previously mentioned patent disclosing and claiming it.

The rise of the main plunger 3| and platen or ram 32 causes the cam 39 to close the normally open limit switch 24, but nothing happens since the main solenoid I3 is deenergized by the opening of the magnetic contactor Ill.

4 Consequently, there is no danger of the operation of the collapsible link I 2 on the return stroke of the main plunger 3|. The main ram 32 continues to rise untilits arm 33 engagesthe collar 35 and lifts the control rod 34, causing the collar 33 to engage and rock the lever 56 and shift the servomotor control valve rod 40 to its neutral position through the motion of the intermediate linkage. The pump N then operates at zero delivery, but immediately goes upon stroke at any tendency of the main plunger 3| to descend. In this manner the main plunger 3| is held at the top of its retraction stroke.

At this point in full automatic operation, however, since the operator has previously moved the switch I to its full automatic position, the limit switch I00 is closed by the rise of the control rod 34 and reenergizes the coil of the magnetic contactor I by way of the branch power line I23, the lines I35, I26 and I25, the limit switch I08, the line I20, the switch I00, the lines I28 and I30, the coil II5, the line I3, the switch I09, the line I31, the oil temperature limit switch III) and the line I36 to the branch power line I22.

The main solenoid |3is thus reenergized and shifts the servomotor control rod 40 toplace the pump upon its forward delivery stroke, caus- 1 ing the main plunger 3| to commence another working stroke with but a momentary halt at the top of its return stroke. The repeated operation ofthe valve-operating solenoid 32 and the collapsible link I2 takes place in the manner previously described upon each working stroke, but is prevented from taking place upon the return stroke by the fact that the main solenoid I3, with v which the valve solenoid 62 is in circuit, is deenergized. The press is halted by the operator when the operator depresses the switch I09 or automatically by the oil temperature limit switch 0 if the oil temperature rises to an undesired height.

The invention is, of course, not limited to presses in which the travel of the press platen is reversed in response to a'predetermined pressure acting thereupon, but may as well be used in connection with presses in which the reversal of the travel of sponse to a predetermined point of travel of the platen. To this end, with reference to Figures 5 and 6, the platen 32 may, ata predetermined point of its pressing stroke and by means of a cam I15, open the switch Ila, which takes the place of switch I0 in the circuit of Figure 2. v 5

Opening of the switch |8a breaks the holding circuit for solenoid 5 (Figure 6), thereby en-.

abling the spring in the pump II to move the latter to full delivery retraction stroke position.

Since otherwise Figures 5 and 6 fully correspond to Figures 1 and 2, the cycle will then continuein the press platen is effected in recombination with reversible hydraulic motor means having a reciprocable ram and a source of pressure fluid therefor with a flow-control member for reversibly controlling the distribution of pressure fluid to said hydraulic motor means, of means including an electrical device for reversibly moving said flow-control member between its forward delivery and its reverse delivery positions through its neutral delivery position, said flow-control-member-moving means including an expanding and collapsing link device, electrical means for effecting the operat on of ,said link device, means responsive to the travel of said ram to a predetermined location for energizing said electrical means to effect the operation of said link device to shift said flowcontrol member in a delivery-reducing direction, and means for deenergizing said electrical means near the end of the travel of said ram in one direction and for maintaining said electrical means deenergized during the opposite direction of travel of said ram.

2. In a hydraulic press control system, the combination with reversible hydraulic motor means having a reciprocable ram and a source of pressure fluid therefor with a flow-control member for reversibly controlling thedistribution of pressure fluid to said hydraulic motor means, of means including an electrical device for reversibly moving said flow-control member between its forward delivery and its reverse defor deenergizing said electrical device near theend of the ram travel in one direction whereby to concomitantly deenergize said electrical means, and for maintaining said electrical means deenergized during the opposite direction of travel of said ram.

-3. In a hydraulic press-control system, the

combination with reversible hydraulic motor means having a reciprocable ram and a source of pressure fluid therefor with a flow-control member for reversibly controlling the-distribution of pressure fluid to said hydraulic motor means, of means including an electrical device for reversibly moving said flow-control member between its forward delivery and its reverse delivery positions through its neutral delivery position, said iiow-control-member-moving means the manner described in connection with Figures 1 and 2 It will be understood that-it is desired to cominvention.

Having "thus fully described the invention,

including an expanding and collapsing link device, electrical means for effecting the operation of said link device connected in circuit with said electircal device for moving said flow-control member, means responsive to the travel of said ram to a predetermined location for energizing said electricalmeans to effect the operation of said link device to shift said flow-control member in a delivery-reducing direction, and means responsive to the attainment of a predetermined pressure in said motor means near the end of the ram travel in one direction for deenergizing said electrical device and concomitantly deenergizing said electrical means and for maintaining said electrical means deenergized during the opposite direction of travel of said ram.

4. In a hydraulic press control system, the

' combination with reversible hydraulic -motor means having a reciprocable ram anda source of pressure fluid therefor: with a flow-control member for reversibly controlling the distribution of pressure fluidto said hydraulic motor means,

of-means including an electrical device for; reversibly moving said flow-control member between its forward delivery and its reverse delivery positions through its neutral delivery posi tion, said flow-contuol-member-moving means including an expanding and collapsing link device, means for supplying pressure fluid to said 1 link device to operate the same, avsolenoidal valve connected to control the supply of pressure fluid in said link device, the solenoid of said valve being connected in circuit with said electrical device, means responsive to the arrival of said ram at a predetermined position for energizing said solenoidal valve to actuate said link device, and means responsive to the attainment of a predetermined pressure in said hydraulic motor means for concomitantly deenergizing said electrical device and said' solenoidal valve.

5. In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocable ram and a source of pressure fluid therefor with a flow-control member for reversibly controlling the distribution of pressure fluid to said hydraulic motor means, of means including an electrical device for reversibly moving said flow-control member between its forward delivery and its reverse delivery positions through its neutraldelivery position, moving means including an expanding and collapsing link device, means for supplying pressure fluid to said link device to operate the same, means responsive to the arrival of said arm at l a predetermined position for lay-passing the supsaid flow-control-member cal devices andfor maintaining the same dc energized during the retraction stroke of the P 7. In a hydraulic press control system, the combination with reversible hydraulic motor means having a reciprocable ram and a reversible 'variable delivery pump'with a. flow-control member for reversibly varying the pump delivery from a forward delivery position through a neutral position to a reverse delivery position, of a press control element connected to said flow-control member and engageable by said ram, a solenoid operatively connected toshift said flow-control member, an expanding and collapsing link device connected between said solenoid and said flow-control member, fluid pressure-operated means including a solenoidal control valve for actuating said link device, means responsive to the arrival of said rain at a predetermined loca-' tion on its stroke in one direction for operating saidsolenoidal valve to actuate said link device and shift said flow-control member in a delivery-reducing direction, means for deenergizing said solenoid to shift said flow-control member to its reverse delivery position, and means responsive to the deenergization of said solenoid for deenergizing said solenoidal valve.

8. In a hydraulic press control system, the combination with reversible hydraulic motor means ,having a reciprocable ram and a reversible variable delivery pump with a flowcontrol member for reversibly varying the pump delivery from a forward delivery position through a neutral position to a reverse delivery position, of yielding means for urging said flowcontrol member into a reverse delivery position, a solenoid adapted when energized to urge said flow-control member. into a forward delivery position, an expanding and collapsing link device connected between said solenoid and said a flow-control member and operable when actuply of pressure fluid to said link device to actuate the same, and means responsive to the attainment of a predetermined pressure in said i motor means for altering the energization of said electrical device to shift said flow-control member into its reverse delivery position, and means responsive to the alteration of energizetion of said electrical device for rendering said by-passing means inoperative.

6. In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocable ram and 'a reversible variabledelivery pump with a flow-control member for reversibly. varying the pump delivery from a forward delivery position through a neutral position to a reverse delivery position, 3 of yielding means for urging said flow-control member in one direction, .an electrical device for moving said flow-control member in the op- 1 posite direction, an expanding and collapsing link 1 device connected between said flow-control member and said electrical device, means responsive I to the arrival of said ram at a. predetermined location on its forward stroke for actuating said link device to effect the moving of said flow-con- 1 trol member to a reduced-delivery position; 1 means for supplying pressure fluid to actuate. 3 said link device, a valve for-controlling said sup- 1 plying means, a secondelectrical device for operating said valve, and means adapted to be actuated near the end of the forward stroke of i said ram for deenergizingboth of said electril5 ated to eifect the shifting ofsaid flow-control member to a reduced delivery position, electrical means for controlling the'actuation of said link device, means responsive to the arrival of said ram at a predetermined location for operating said electrical means to actuatesaid link device, means responsive'to the travel of said ramupon its forward stroke for deenergizing said solenoid to reverse the delivery of 'said pump, and means responsive to the deenergization of said solenoid for concomitantly deenergizing said electrical means.

I 9 In a hydraulic press control system, the

combination with reversible hydraulic motor means having a reciprocable ram and a reversible variable delivery pump with a flow-control member for reversibly varying the pump delivery from 0 a forward delivery. position through a neutral means for supplying pressure fluid to actuate said link device-anelectric motorfor driving said pump, and means controlled by'the fluid v pressure actuating said link whereby, upon a member in one direction,

failure of said fluid pressure, said motor will be rendered inoperative.

10. In a hydraulic press control system, the

a neutral position to a reverse delivery position,

of yielding means for urging said flow-control moving said flow-control member in the oppositedirection, an expanding and collapsing link device connected between said flow-control member and said electrical device, means responsive to the arrival of said ram at a predetermined location on its forward str'oke for actuating said link device to effect the moving of said flow-control member. to a reduced-delivery position, means for supplying'pressure fluid to actuate said link. said supplylngmeana'a second electrical device for operating said valve, means adapted to be an electrical device for device, a valve for controlling actuated near the end of the forward stroke of said ram ior deenergizing both of said electrical devices, and for maintaining the same deenergized during the retraction stroke of the ram; a motor for operating said pump, and means controlled by the fluid pressure actuating said link to control the operation of said motor whereby, upon a failure of said pressure, said motor will be rendered inoperative.

11. A hydraulic press comprising in combination a press ram, means 'for supplying pressure fluid to said ram for actuating the same, electric means for driving said fluid supply means, link means including a fluid pressure chamber'oper able to vary the delivery of said pressure fluid supply means, and means adapted in response to 'a predetermined pressure condition in said chamher to prevent said driving means from further driving said pressure fluid supply means. wan-ran ERNST. VICTOR S. SHAW,

PAUL (J. Pococx. nnnnna'r 8. 500mm.

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