US2249149A - Auxiliary hydraulic device for presses - Google Patents

Description

July 15, 1941.

H. F. M MlLLlN AUXILIARY HYDRAUL Original Filea Aug. 16, 1934 10 DEVICE' FOR PRESSES 4 Sheets-Sheet 1 11v VEN TOR flown/e0 E. NAc/V/Lu/Y A TTORNEYS July 15,1941.

H. F. M MILLIN AUXILIARY HYDRAULIC DEVICE FOR PRESSES Original Filed Aug. 16, 1934 4 Sheets-Sheet 3 IN VE N TOR flan 4R0 E NAc/V/Lu/Y A T T ORNLYS July 15, 1941.

H. F. M M|LLIN @UXILIARY HYDRAULIC DEVICE FOR PRESSES Original Filed Aug. 16, 1934 4 Sheets-Sheet 4 IN VEN TOR flame/w f. Nae/Van A TTORNE Y3 various hydraulically-actuated devices Patented July 15, 1941 AUXILIARY nvnRAULIc DEVICE FOR PRESSES Howard F. MacMillin, Mount Gilead, Ohio, as-

signor to The Hydraulic Press Corporation, Inc., Wilmington, Del., a corporation of Delaware Original application August 16, 1934, Serial No.

Divided and this application August 24, 1936, Serial No. 97,579

7 Claims.

This invention relates to presses, and especially to those having their platens moved by nonhydraulic means.

One object of my invention is to provide a press having a platen moved by any convenient means whether hydraulic or non-hydraulic, and devices for generating fluid pressure operated by the motion of the platen, the fluid pressure thus generated being available or operating and/or providing pressure control.

Another object is to provide a hydromechanical press having its platent moved by whatever means, with an auxiliary hydraulic pressing ram connected to an external hydraulic circuit, with means for releasing the pressure in this circuit and/or reversing the direction of flow of the hydraulic fluid so as to remove the pressure from the auxiliary pressing plunger at the instant the pressure reaches a predetermined amount.

This application is a division of my copending application, Ser. No. 740,148, filed August 16; 1934, now matured into Patent No. 2,128,152.

In the drawings:

Figure 1 is a front elevation, partly in section, showing a press embodying an arrangement for flash pressure control, or release of pressure when a predetermined pressure has been reached.

Figure 2 is a front elevation, partly in section, of a press also embodying the flash control arrangement, but also including a reversible delivery pump in a closed hydraulic circuit to supply additional fluid to the auxiliary pressing plunger.

Figure 3 is a front elevation, partly in section, of a'p'ress also embodying the flash control arrangement, but having a variable delivery pump in an open hydraulic circuit wherein the pump discharge is valved to control the direction of movement of the press platen.

Figure 4 is a wiring diagram of an electrical circuit adapted to perform the flash control operation for the presses shown in Figures 1 to 3,

inclusive.

Press with single-acting generator rams I Referring to the drawings in detail, Figure 1. shows a press having a 'base I joined by side members 2 to the top member 3, as by the strain rods 4, on which are threaded the-nuts 5.

guide portion I is assisted by the retaining plates 9 bolted to the side members 2 of the press.

The press platen 8 may be moved in any convenient manner, such as mechanically or hydraulically. For purposes of illustration, a geardriven mechanical crank press is shown, but other types may be used without departing from the scope of my invention. In the form of press shown, the platen 8 is provided with a cross shaft III journaled in bearings II on the upper portion of the platen 8. Pivotally engaging the cross shaft III of the platen 8 is a connecting rod I2 having a lower bearing I3, surrounding the cross shaft I0. At its upper end, the connecting rod I2 is provided with an upper bearing III, which surrounds the crank portion I5 of the main drive shaft I6. The latter is journaled in bearings Il, mounted upon the side members 2 of the press.

The driving end of the main driven shaft I6 is provided with a gear I8 for this purpose. The gear I8 is connected by a clutch mechanism within the clutch housing IS in such a manner that the gear I8 may be connected or disconnected from the main drive shaft I6, as desired. The clutch mechanism within the clutch housing I9 is actuated by the crank arm 20 mounted on the clutch shaft 2| and connected by the link 22 to the pedal rod 23. The latter is reciprocably supported in the bosses 24 attached to one of the side members 2, and is secured at its lower end by the pivotal connection 25 to the foot pedal 26. By depressing or releasing the foot pedal 26, the gear I8 may be made to operatively engage the main drive shaft I6, or rotate loosely upon it. In this manner, the foot pedal 26 controls the press to provide for its executing working strokes or for its remaining idle, as may be desired.

The gear I8 is driven by a pinion 2'I, meshing therewith, and mounted upon' the countershaft 28 journaled in bearings attached to the side members 2. The opposite end of the countershaft 28 from the pinion 2'I bears a flywheel 30 and a pulley 3 I, whereby the press may be driven, as from an electric 'motor belted to this pulley.

Accordingly, when the pulley 3| is thus rotated, the gear I8 also rotates-loosely upon the main drive shaft I6. When the foot pedal 26 is depressed, the gear 18 drivingly engages the main shaft I6 and'c-auses the crank portion I5 thereof to move in an orbital path. movement causes the connecting rod I2 to move up and 6 down, carrying with it the platen 8. I

The platen 8 in its lower portion is provided 'the passages 50 and within the cylinder bores 32 are hydraulic gen- 5 with a pair of generator cylinderqiores 32 and an auxiliary pressing cylinder bore 33. These cylinder bores are connected at their ends by Reclprocably mounted erator rams 45 with heads 41 and having their lower ends secured in sockets 35 in the base I (Figure 1). Leakage from the generator cylinders 32 is prevented by the provision of the packings 31, adapted to be compressed by glands 38. Mounted for reciprocation in the auxiliary pressing cylinder bore 33 is the auxiliary pressing ram 45, having an upper enlarged portion 48 and a lower reduced portion 49. Leakage from the cylinder bore 33 is prevented by the packing 43, engaged by the gland 44, which surrounds the reduced portion 49 of the auxiliary pressing ram 45.

In Figure 2 it will be observed that the righthand cylinder 53 is connected at its upper end by the passage 55 to the space above the enlarged head 48 of the auxiliary hydraulic ram 45, whereas the upper end of the cylinder 52 is connected by the oblique passage 55 to the space below the enlarged head 48. The pistons 51 and 58, however, are provided with hollow longitudinal bores 59, and thus act like telescoping connections, and to some extent like pistons. The bores 59 are connected at their lower ends to the pipes 50 and 5|, respectively.

In the arrangement of the present invention,

the flash type of operation is employed. That is, the pressing pressure is released at the instant it reaches a predetermined value so that substantially no pressure is henceforth exerted upon the work-piece during the remainder of the working stroke. To accomplish this result, an electrical circuit is disclosed below, but it will be understood that mechanical arrangements for accomplishing the same result might also be em- I ployed.

ing contactor switch, generally designated I35.

The circuit also contains a double push button starting switch I34, a throw-out switch I29 and an electrical limit switch I35 The mechanical parts operated by the clutch solenoid I3I (Figure 1) consist of a pair of collars I31 on the clutch control rod 23, these being engaged by one endof the solenoid lever I 33 which is pivoted at its mid-portion, as at I39, and connected by' the connecting rod I40 to the armature I of the clutch-operatingsolenoid I3 I.

The electrical limit switch I35 serves to place the mechanism out of operation by releasing the clutch through the action of the clutch-operating solenoid I3I, and is operated by the collar I42 on the actuating shaft I43. The latter is 85 reciprocably supported in the bearing bosses I44 attached to the machine, and carries an adjust-4 able collar I45 for regulating the position atwhich the limit switch I 35 is actuated. A second adjustable collar I45 serves as a stop to rest against the boss I44 when the actuatingshaft I43 is in its downward position. The adjustable collar I45 is engaged by the bored end I41 of the arm I48, the base I49 thereof being secured to-the platen, as by'the bolts I50. The b0red 75 end I41 loosely surrounds the actuating shaft I43. Consequently, when the platen 8 on its return stroke rises to its maximum position, the end I 41 of the arm I48 lifts the collar I45 and the shaft I43, thus causing the collar I42 to throw the limit switch I35 to deenergize the clutch-operating solenoid I3l and to allow the clutch I9 to return to its open position, severing the power connection to the main drive shaft I5.

Each of the press arrangements shown in Figures 1, 22nd 3 employs a double-headed piston valve similar to the piston valve-having a valve rod I04 with'spaced heads I06 and I0'I for distributing the fluid and of reversing its direction. In the present instance, the valve rod I04 is attached to the armature I5I of the valve-operating solenoid I33. When the solenoid I33 is energized, the valve rod I04 is pulled downward so that the piston heads I05 and I01 are in their lower positions. As soon as the solenoid I33 is deenergized, however, the valve rod and its heads move upward under the urge of the coil spring I52. V

In the press arrangement shown in Figure 2, the upper end of the valve rod I04 is provided with a clevis I53, which-is connected to the bellcrank I54 by the connecting'link I55. The bellcrank I54 is pivotally mounted upon the frame bracket I56, and its opposite end is connected to the pump reversal shaft I51 by the link I58. As a result, therefore, the shift of the valve rod I04, through the action of the solenoid I33 or 'coil spring, simultaneously causes the valve I05 ing care of insuflicient or excess fluid in the circuit.

The circuit of'Figure 3 is an open circuit wherein the pump discharge is valved-to control the direction of movement of the press platen. In Figure 3 the valve rod I04 is actuated bythe solenoid I33 and the coil spring I52. This pump H4 is a variable delivery pump having a servocylinder II5 connected by a pilot line II5 to the main pump line I", so that the flow control element of the pump H4 is shifted thereby when the pressure in the lines H5 and III rises beyond the pressure setting of the servo-cylinder II5, as adjusted by the hand wheel H8. The pressure switch I30 controlling this solenoid I33 also acts as a relief valve, through its port I98 and pipe. I99. Hence, the high pressure relief valve H2 in Figure 3 serves merely as an added safety device and'may be optionally omitted.

The operation of the electrical circuit for controlling the movements of the presses shown in Figures 1, 2 and 3 is substantially the same for all three arrangements. A single description will, therefore, suffice, after which theslight variations in the hydraulic circuits will be individually armature I64 against the urge of the coil spring I65, and closing the respective circuits through its three contactor bars I66,, I61 and I68. The contactor bar I66 closes the circuit between the power lines I6I and I62 by way of the limit switch I36, the branch lines 169, I and "I, and the push button switch I29. This action maintains the energization of the operating coil I63 of the clutch-operating contactor switch I32 after the starting push button switch I34 has been released. I

The closing of the contactor bars I61 and I60 of the contactor switch I32 01053517118 circuit between the power lines I61 and I62 by way of the windings of the clutch-operating solenoid I3I. This energizes the solenoid I3l, attracts the armature I4I thereof and operates the clutch rod 23 to engage the clutch I9 and start the platen moving downward.

The depressing of the starting push button switch I 34, previously mentioned, also causes the lower bar thereof to close the circuit between the power lines I6I and I62 by way of the branch line I12, the operating coil I13 of the valve-operating contactor switch I35, the branch lines I14,

I93 and the exhaust line I94 back to thetank I59. This instant release of the pressure after a predetermined pressure has been reached is knownas the-flash: pressure reversal as distinguished from the dwell pressure systems according to whichthe pressure is allowed to rise to a predetermined amount at which it remains until the press is reversed..

I10 and HI; and the operating coil I63 of the clutch-operating contactor switch I32. This ac,- tion shifts the armature I15 of, the contactor switch I35, closing its three contactor bars I16,

I11 and I10 against the urge of the coil spring I19.

The closing of the contactor bar --I16 closes the The platen 0 thus continues to move downward without applying pressure to the workpiece, and then passes upward on its return stroke. As it nears the limit of ;its upward m0tion,'the end I41 of the arm I40 lifts the collar I45 and thewrod I43, causing the collar I42 thereon to throw the limit switch I36. This action breaks the circuit, energizing the-clutchoperating solenoid I3I, causing it to release the clutch-operating rod 23. The clutch I9 accordingly opens, breaking the mechanical connection between the source of .power and the main driving shaft I6 of the-press. The platen. 8, therefore, comes to rest at the upper limit of its stroke and recommences another working stroke only when the starting push button switch I34 is again depressed. When this occurs, the foregoing cycle of operation is repeated.-

, The operation 10f. the press circuit shown in 3 Figure 2 is electrically the same as that shown in Figure 1, but is hydraulically somewhat different. The starting push button'switch' I34'isdepressed as-before, and the so1enoids'I3I and -I33 are gization of the operating coil I13 of the contactor switch I35 after the starting push button similarly energized, causing the clutch- I9 to be closed and the valve rod I04 to be pulled'downward in the manner previously described. The same action causesthe pump control rod I51 to be shifted through the motionof the bell-crank I54, causing pressure fluid to be discharged I through the port 62 of the pump 64', the port 63 enlarged piston heads 41 in the cylinderbores 32 passes through the passageways into the space 33 above the auxiliary pressing plunger 49. The latter thus moves outward, and the fluid displaced thereby-passes into the space beneath the piston heads 41 of the pressure-generating plungers 46. The fluid under pressure also backs up in the plunger bores 85 and the pipe line I90, this being communicated to the pressure switch I30 by the branch line I9I (Figure 1). (Any additional fluid required by the press is supplied through the pipe line I90 and the check valve I60 from the tank I59.) When this pressure becomes great enough to overcome the force of the coil spring in the pressure. switch I30, the latter opens, breaking the circuit energizing the valve-operating solenoid I33. The valve rod I04 and the valve heads I06 and I01 then move unward under the urge of the coil spring I52, the valve heads I06 and I01 coming to rest in the dotted positions (Figure 1). The fluid pressure within the auxiliary pressing plunger chamber 33 is immediately released, and no further pressure is placed upon the work-piece, as the fluid henceforth passes from the cylinders 32 through the plunger bores 85, the pipe line I90, the branch line I92, the piston valve I 05, the branch line correspondinglybecoming the suction-port. The fluid pressure coming from the pump 64 by way of the pipe line 60 and the bore 59 in the plunger 51 passes into the cylinder bore 53 and thence into the space above the auxiliary pressing plunger 49, causing the latter to move outward and exert its pressure upon the work-piece. At the same time, the fluid displaced from beneath the pressing plunger 49 passes outward through the oblique passage 56into the cylinder bore 52, and thence is drawn back to the pump 64 by way of the bore 59 in the plunger 50 and the pipe line 6| running to the suction port 63 of the pump 64. The differential valve 15 causes a constant supply of fluid to be available tothe pump 64.

When the platen 8 and the auxiliary -pressing plunger 49 of Figure 2 have exerted a sufllcient pressure upon the work-piece to cause the pressure switch I30 to be thrown by the action of the fluid backing up in the pipe line 60 and the branch line I9I, the solenoid I33 isdeene'rgized in the same manner as previously described. The piston valve I 05 then shifts, and its heads I06 and "I 01 move into their upper or dotted positions. Simultaneously with this, the pump control rod I51 moves inward through the action of the bellcrank I 54, reversing the flow of fluid from the pump 64 and causing the port 63 to become the compression port and the port 62 the suction port. Fluid is then withdrawn from the cylinder 53 and the space above the auxiliary pressing plunger 49 by way of the pipe line 60, and the auxiliary pressing plunger 45 moves inward to release the pressure upon the work-piece. At the same time, pressure fluid is supplied to the under side of the auxiliary pressing plunger head 48 by way of the pipe line SI, and the oblique passageway 55, thus accelerating the inward motion of the plunger 45. Throughout the remainder of the working stroke, therefore, substantially no pressure is exerted upon the work-piece. The platen 8 then reverses its motion, and trips the limit switch I38 at the upper limit of its motion, coming to rest in the manner previously described for Figure 1.

The operation of the press circuit shown in Figure 3 follows the electrical steps previously described for Figure 1. The energization of the solenoids I3I and I33 starts the platen 8 moving downward and exerts pressure upon the workpiece by the action of the auxiliary pressing plunger 49 as previously disclosed. The pump discharge passes byway of the pipe line II'I and the check valve III to the piston valve I05,

thence along the pipe line I08 through the right-.

hand plunger 51 into the space above the auxiliary pressing plunger 49. The fluid displaced from beneath the latter is drawn outward through the oblique passageway 58, the plunger 58 and the pipe line I09, the piston valve I05, and the pipe line II3 to the tank 84. The pump II4 obtains liquid by way'of its suction line -I I9 running to the tank 84. The high pressure regulating valve I I2 at a predetermined pressure discharges fluid from the line I08 into the discharge line I I3, leading back to the tank 84. The high pressure check valve III prevents a backward flow of fluid.

When the pressure exerted upon the workpiece by the auxiliary pressing plunger 49 reaches the pressure required to throw the pressure switch I30, the latter opens the circuit energizing the valve-operating solenoid I33. The heads I08 and I! of the piston valve I then move upward (Figure 3), causing the pump discharge from the line II! to be passedthrough the valve I05 into the line I09 leading to the space beneath the auxiliary pressing plunger 49 by way of the oblique passageway 56 and the plunger 58. The auxiliary pressing plunger 49 is rapidly forced inward under the action of this pressure, and the fluid on its opposite side escapes through the cylinder 53, the bore 59 in the plunger 51, the pipe lines H0 and I08, the valve I05 and the discharge line I I3 to the tank 84. Thus the pressure upon the work-piece is instantly withdrawn when the predetermined pressure is reached, and the platen 8 continues downward for the remainder of its working stroke without exerting any substantial pressure upon the work-piece.

In the pressure switch I30 shown in Figure 3, a slight modification has been made over the pressure switches I30 previously described for.

Figures 1 and 2. The pressure switch I30 of Figure 3 is supplied with a side port I98, which communicates'by way of the branch line I99 with the discharge line II3 leading to the tank 84. This causes the pressure switch I30 of Figure 3 to function also asa relief valve, and to discharge fluid when the pressure switch I30 is shifted.

In the foregoing cycle of operations described for Figures 1 to 4, inclusive, the platen has been caused to come to rest when it reaches the top of its return stroke, this action being obtained through the operation of the limit'switch I36. In order to cause the press to repeat its stroke automatically without stopping at the upper limit of its return stroke, the normally-closed positionactuated switch I36 may be made non-effective by bridging it with the lines 200 and 2! containing the normally-open manually-operated switch 202 in parallel with the positionswitch I38 (Figure 4). When the switch 202 is closed, the clutch-operating contactor switch I32 and the solenoid I3I remain continuously energized, irrespective of the opening and closing of the position switch I38, causing the press platen 8 to make any desired number of working strokes in succession. When the switch 202 is opened, however, the position switch I35 again becomes operative to halt the platen 8 at the upper limit of its return stroke.

It will be observed that in the circuit of Figure 3, the variable delivery feature of the pump H4 is utilized as a means of pressure control only. It will be understood that I desire to comprehend within my invention such modifications as may be necessary to adapt it to varying conditions and uses.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

- 1. In combination in a press, a mechanically operable platen having associated therewith a cylinder, a ram reciprocably mounted in said cylinder, a fluid source adapted to supply fluid to said cylinder, mechanical means operable to ad vance said platen together with said ram while simultaneously causing said platen to create fluid pressure in said cylinder to additionally advance said ram, and means responsive to a predetermined pressure on said ram for releasing said.

last mentioned pressure and maintaining said ram substantially stationary while said platen continues its advancing stroke.

2. In combination in a press, a mechanically operable platen having associated therewith a main cylinder and an auxiliary cylinder, said cylinders being hydraulically connected with each other, a ram reciprocably mounted in said' main cylinder, a plunger mounted in said auxiliary cylinder and permitting relative movement said ram, and means responsive to a predetermined pressure on said ram for releasing said last mentioned pressure and maintaining said ram substantially stationary while said platen continues its advancing stroke.

3. In combination in a press, a mechanically movable platen, mechanical means to move said platen through a predetermined working stroke, a hydraulically-operable ram associated with said platen and adapted to be advanced thereby, a fluid source for supplying fluid to said ram, means associated with said platen and responsive to the advancing movement thereof for exerting fluid pressure on said ram to additionally advance the same, and means responsive to the attainment of a predetermined pressure after the completion of a part of the working stroke for completely releasing pressure fluid on said ram while said ram continues its advancing stroke.

4. In combination in a press, a mechanically movable platen, mechanical means to move said platen through a predetermined working stroke, a hydraulically-operable ram associated with said platen and arranged for mechanical advancement by said platen, a fluid source for supplying fluid to said ram, means associated with said platen and responsive to the advancing moyement thereof for creating fluid pressure on said ram to additionally advance the same, a reversing valve for controlling the direction of flow of the fluid from said fluid source to said ram, and means responsive to the attainment of a predetermined pressure after the completion of a part of the working stroke for reversing said reversing valve while said platen continues its advancing stroke to completely release the pressure exerted by said ram upon the workpiece.

5. In combination in a press, a mechanically movable platen, mechanical means to move said platen through a predetermined workingstroke, a hydraulically operable ram associated with said platen, and means for supplying fluid pressure (to said ram to advance the same, means associated with said platen and responsive to the advancing movement for exerting additional fluid pressure on said ram to additionally advance said ram, and electrically actuated means responsive to the attainment of a predetermined pressure after the completion of a part of the working stroke for completely releasing the pressure on said ram while said platen continues its advancing stroke. l

6. In combination in a press, a mechanically movable platen, mechanical means to move said platen through a predetermined working stroke, a hydraulically operable ram associated with said platen and adapted to be mechanically advanced by the movement of said platen, means for supplying pressure fluid to said ram for hydraulically advancing the same, said means including a by-passing valve, means associated with said platen and responsive to the advancing movement thereof for exerting additional fluid pressure on said ram to additionally advance said ram, and electrically actuated means responsive to the attainment of a predetermined pressure after the completion of a part of the working stroke for reversing said by'-passing valve to completely release the pressure exerted by said ram upon the workpiece while the advancing stroke of said platen continues, said pressuresupplying means including -a reversible delivery pump with the reverse member thereof operatively connected to said by-passing valve.

7. In combination in a press, a mechanically movable platen, mechanical means to move said platen through a predetermined working stroke;

stantially without exerting any substantial pressure upon the workpiece for the remainder of the advancing stroke 01' said platen.

' HOWARD F. MAOMHLIN.

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