US2113115A

US2113115A - Hydromechanical press

Info

Publication number: US2113115A
Application number: US727550A
Authority: US
Inventors: Howard F Macmillin; Don C Youngblood
Original assignee: HYDRAULIC PRESS CORP
Current assignee: HYDRAULIC PRESS Corp
Priority date: 1934-05-25
Filing date: 1934-05-25
Publication date: 1938-04-05
Anticipated expiration: 1955-04-05

Description

April 5, 1938. F, MacMlLLlN ET AL 2,113,115

. HYDROMECHANICAL PRESS' Filed May 25, 1954 4 Sheets-Sheet l April 5, 1938. H. F. Mac-MILLIN ET Al. 2,113,115

V HYDROMECHANICAL PRESS Filed May 25, 19.1.54 4 Sheets-Sheet 3 1 /A/l/E/V TORS ATTORNEYS Filed May 25, 1934 4 Sheets-Sheet 4 Patented Apr. 5, 1938 UNITED STATES PATENT oFElcE 2,113,115 i HYDRQMECHANICAL PnEss Howard F. MacMillin and Don C. Youngblood,

Mount Gilead, Ohio, assignors, by mesne assignments, to The Hydraulic Press Corporation, Inc., Wilmington, Del., a corporation ol' Dela- Ware Application May 25, 1934, serial No. '127,550

3 Claims.

cal press having a horizontally-disposed hydraulic cylinder-and-piston assembly arranged to move a vertically-disposed platen, as through toggle or crank connections therebetween.

Another object is to provide a hydromechanical press wherein a hydraulic ram moving in one direction is caused to move a platen in a direction perpendicular thereto.

Another object is to provide a hydraulic press having mechanical means for adjusting the maximum position reached by the platen during operation.

Another object is to provide a hydromechanical press wherein an adjustable wedge is used to regulate the position reached by the platen in its motion.

Another object is to provide a hydraulic press having a hydraulic cushion in one of the pressing surfaces, this cushion embodying means for stopping or reversing the action of the press when the pressure upon the cushion reaches a predetermined amount.

Another object is to provide a hydromechanical press with a hydraulic cushion in one of the pressing surfaces thereof, together with an electrical switch actuated by the pressure undergone by the cushion in such a manner that the switch showing the control valve in longitudinal section, and in a neutral position;

Figure 2 is a longitudinal section through the control valve shown in Figure 1, but with the parts arranged in the forward position so as to produce a down-stroke of the platen; v

Figure 3 is a longitudinal section through the control valve shown in Figures 1 and 2, but with the parts in a reverse position to produce an upward stroke of the platen;

Figure 4 is a side elevation of the press shown in Figure 1, the control valve being omitted to conserve space;

Figure 5 is a vertical section along the line 5-5 of Flgure 1;

Figure 6 is a wiring diagram of the control circuit for the press of my invention;

Figure 'l is an enlarged detail view showing the crank shaft and solenoid connections.

General construction. of the press Referring to the drawings in detail, Figure 1 shows a press having a base l and a top piece 2 interconnected by side members 3 through the agency of the strain rods l, on which are threaded the nuts 5. Secured to the side members 3, as by the screws 6, are the retaining members l. The latter are arranged adjacent to the guide portions 8, serving to receive the press platen 9 and guide it in its vertical reciprocation. The platen 9, on its lower surface, is provided with a slot I adapted to hold a die, work pieces or other suitable devices. Journaled in the bearings II inthe upper partcf the platen 9 is a cross shaft I2 (Figures 1 and 5), to which a link member I3 is pivotally secured.

The opposite end of the link member i3 is pivotally mounted upon the cross shaft I4, which is journaled in the bearings l on the yoke portion I6 of the hydraulic cylinder Il. The cross shaft I4 also pivotally supports the link members I8, whose upper ends are pivotally mounted upon the cross shaft I9. The ends of the cross shaft I9 are journaled in the bearings 20, arranged within a movable anchor block 2|, which in turn is reclprocable along vertical guide portions 22v on the side members 3 and held in position by the side plates 23, bolted thereto by the screws 24 (Figure l). The upper part of the anchor block 2l is threaded to receive the vertical rods v 25. The latter pass upwardly through the top member 2 and are provided with coil springs 26, held in place by the threaded nuts 21. Accordingly, the anchor block 2| is yieldably urged upward against. the press top member 2 by the springs 26. The anchor block 2l likewise contains a stud screw 28, which is received within, the bore 29 of the top member 2. The latter is hollow to provide a tank for the uid used to operate the various hydraulic mechanisms of the press.

To adjust the position of the anchor block 2|, a movable wedge 39 is provided (Figure 5), and interposed between the anchor block 2| and the lower surface of the press top member 2. When this Wedge is moved horizontally, as by the hand wheel 3| upon the threaded stud shaft 32, the wedge 39 moves in or out and consequently moves the anchor block 2| up or down. 'This adjustment of the position of the anchor block 2| regulates the lowest position of the platen 9 during its working strokes.

'I'he hydraulic cylinder I1 contains a piston 33, whose piston rod 34 is threaded into a swivel block 35, arranged to swivel around the shaft 36. 'I'he latter is mounted upon a bracket 31, secured to the side members 3 of the press (Figure 5). To prevent leakage between the piston rod 34 and the cylinder |1, through which it passes, an adjustable gland 38 is provided, and arranged to compress a packing 39, whereby such leakage is prevented.

The base portion I of the press contains a cushion block 49 reciprocable in a bore 4| against the pressure of the coil spring 42. The lower portion of the cushion block 49 serves as a hydraulic piston, and the space between it and the bottom of the bore 4| contains fluid, such asA oil. The leakage of this fluid is prevented by the adjustable gland 43 adapted to compress the packing 44 around the cushion member 49.

A pipe 45 leads from the bottom of the bore 4| to the switch-actuating cylinder 96. Within this cylinder 96 is a piston 95 reciprocable against theurge of a coil spring 91. The tension of the spring 91 is adjusted by the threaded plug 98, through which passes the piston rod 94. 'I'he latter is adapted to engage the switch knob 93 of an electrical switch 99, whose connections will be hereinafter more fully disclosed. Thus when the platen 9 causes pressure to be exerted upon the cushion 49, the latter will transmit this pressure by the fluid within the bore 4| to the switch cylinder 96. When this pressure becomes sufficient to overcome the resistance of the spring 91, the piston rod 94 will engage the knob 93 and throw the switch 99.

Controlling devices for the press 'I'he press is arranged so that it may be operated in a variety of ways. First of all, it may be operated by hand, so that each motion of the platen 9 downward or upward is controlledby a hand lever shifted by the operator.

The press may likewise be controlled for semiautomatic operation, whereby the plunger performs a working stroke, reverses itself, proceeds to the top of its return stroke and automatically cornes to rest; or else it may be controlled for "completely automatic operation, whereby the plunger performs a working stroke, reverses itself, returns to its starting position, performs another working stroke, reverses itself again, and so on, repeating the working strokes indefinitely 'until stopped by the operator. The reversal of the platen may be either pressure controlled so as to occur when the pressure exerted by the platen reaches a predetermined amount; or position-controlled, as when the platen reaches a predetermined position. These results are obtained by the control devices shown in Figures 1 and 4, and by the electrical circuit shown in Figure 6.

these being connected to the discharge pipe |14, y leading to the tank |15 of a hydraulic pump |16.

The valve casing |63 also contains ports |19 and |89, from which pass the pipes |8| and |82. These proceed respectively to the opposite ends of the hydraulic cylinder |1 (Figure 5). Thus when the valve member |64 is set, as shown in Figure 1, the pump by-passes its fluid and the press remains in a neutral position. In the Figure 2 arrangement, pressure fluid passes through the pipe |8| into the space in front of the piston head 33, causing the cylinder |1 to reciprocate and execute a downward motion of the platen 9 (Figure 5). Conversely, when the valve member |64 is arranged as shown in Figure 3, pressure fluid will enter the space behind the piston head 33 by way of the pipe |82, causing the cylinder I1 to reciprocate rearwardly and draw the platen 9 upward. Thus the operation of the valve member |64 may-be controlled manually by the hand lever or else electrically by the action of the solenoid |56.

Electrical control circuit The electrical circuit whereby the solenoid |56 and the electrical accessories of the press are connected or disconnected is shown in Figure 6. Electrical energy for the operation of the circuit is received from the

power lines

55 and 56 and passes to the magnetic switch, generally designated 50. The magnetic switch 50 is a twopole normally-open main switch, which is provided with switch arms 59 and 60, adapted to engage switch points 6| and '62, to which the power lines -55 and 56 are respectively connected. The switch arms 59 and 60 are normally kept out of contact with the switch points 6| and 62 by being mounted upon the shaft 63, which is rotated in the direction of the arrow by the spring 53 attached to the arm 52 and anchored to the hook 54. The solenoid |56 isenergized by the lines 51 and 58 coming from the switch arms 59 and 60.

The magnetic switch 50 is rotated in the opposite direction to thc arrow and thereby closed by an electrical vpilot circuit connected across the

lines

55 and 56. This pilot circuit comprises three branches 65, 66, and 61, having'a common circuit portion 68, connecting each branch to the power line 56. The branches 85, 66 and 61 also have a common circuit portion 69 connecting them to the power line 55. The circuit 68 includes the holding coil 1I, which, when energized, serves to close the switch 50, this action being performed by its attracting the armature 12 attached to the switch shaft 63, as

at 13. The opposite end of the armature 12 carries a normally-open contactor bar 14. When the holding coil 1| is energized, the contactor bar 14 engages the

contact arms

15 and 16, thus connecting theline 65 with the line 69, and completing the pilot circuit through the former.

The line 68 contains the manually operated switch (Figure 6), whereby the holding coil 1| may be permanently de-energized. The line 68 contains a branch line 19, leading to a normally-closed emergency reverse push button switch 80, from the opposite side of which leads the line 8| to one arm 84 of the double-pole double-throw switch 83. To the opposite arm 85 thereof is attached the line 82 leading to the Contact arm of the magnetic switch 50.

The double-pole double-throw switch 83 contains a pair of switch points 86 and 81 which, when engaged by the

switch arms

84 and 85, will close `Jthe circuit through the normallyclosed pressure-responsive switch 90. Conversely, when the

arms

84 and 85 engage the opposite contact points 88 and 89 of the double-throw switch 83, the circuit will be closed through the normally-closed lower position switch 9| operated by the extension |50 of the platen 9.

Assuming the

switch arms

84 and 85 to be engaging the switch points 86 and 81, when the pressure within the chamber 4| beneath the cushion exceeds Va predetermined amount and throws the pressure reverse switch 90 by means the spring |51.

of the pressure cylinder 96 and the piston rod 94, the latter disconnects the pilot circuit and dcenergizes the holding coil 1| of thc magnetic switch 50, thereby de-energizing the solenoid |56. The spring |51 then causes the valve member |64 to move to its Figure 3 position, thus starting an upward stroke of the platen.

If, on the other hand, the

arms

84 and 85 of the double-throw switch 83 are closed upon the contact pointsl 88 and 89, the platen-operated lower position switch 9|, which is normally closed, will be thrown open when the switch rod |03 is moved downward by the platen until the collar |02 engages the switch knob |0| and opens the switch. This again de-energizes the holding coil 1| ofthe magnetic switch 50, and accordingly de-energizes the solenoid |56, and thus in a similar manner to that previouslydescribed, causes the valve member |64 to be'shiited to its reverse position (Figure 3) under the action of Thus by throwing the doublethrow switch 83 in one direction, the press bccomes reversible when a predetermined pressure is reached, whereas by throwing it in the opposite direction the press becomes reversible when a predetermined position is reached.

When the holding coil 1| has been once cuergized, however, and the contactor bar 14 caused to engage the

contact arms

15 and 16, the holding coil 1| will be maintained in an energized condition through the

lines

82 and 69, togethmwith either of the circuits previously described, until either the emergency reverse switch 88, thc pressure reverse switch 90, or the lower position reverse switch 9| is opened.

The holding coil 1| is connected by the

lines

68 and 19 through the push button starter switch |2 and the lines I3 and 69 to the power line 55, previously mentioned. Assuming that the magneticy switch 50 is open (Figure 6) and the varrious circuits de-energized, the closing of thc manually operated push button starter switch ||2 energizes the pilot circuit through the

lines

68, 19, H3, and 69. This energizes the holding coil 1| and closes the magnetic switch 50. The contacter bar 14 then engages the

contact arms

15 and 16, maintaining the holding coil 1| in an energized condition even when the push button starting switch I|2 is released and opened.

Under the action of the above described circuits, the platen will move downward and engage the dies and Work pieces, reversing itself when the predetermined pressure or the predetermined position is reached, according to the setting ol the double-throw switch 83. The platen then rcturns to its topmost position and comes to rest. This mode of operation is termed semi-automatic operation.

When completely automatic operation is desired, so that the platen immediately starts another downward stroke after reaching its topmost position, the circuit shown at the bottom of Figure 6 comes into play. This circuit includes the manually-operated switch ||5 connected on one side to the line 68 by the line 61 and on the other side by the line ||6, running to the upper position switch ||1. The latter is a normallyopen switch which is closed when the platen pushes the control rod 3| upward and causes the collar |20 to engage the switch knob |2| and close the switch ||1. This again energizes the holding coil .1| of the magnetic switch 50. thus energizing the solenoid |56, shifting the valve member |64 to its .working stroke position (Figure 2), and causing a downward stroke of the platen to take place. The platen will then move downward, release the upper position switch I il, and will continue its movement until it causes either the pressure control switch or the position-controlled switch 9i to be thrown, thereby de-energizing the solenoid |56 and reversing the' action of the press. In this manner, the press is caused to repeat its working strokes indefinitely until the manual switch H5 is opened.

Ihe reversal of the platen at the end of a working stroke, either at position limit or at "pressure limit, together with an electromechanical circuit for operating the press in a semi-automatic or completely-automatic manner, has been disclosed in the present specification.

It will be understood that we desire to comprehend within our invention such modifications as may be necessary to adapt it to varying conditions and uses.

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

1. In combination in a press, a movable platen, a hydraulic cylinder-and-piston assembly adapted to move said platen, a cushion adapted to be actuated by said platen, and means for causing the reversal of motion of said platen responsive to the attainment-of a predetermined pressure upon said cushion, said reversing means comprising a member adapted to reverse the movement of a fluid, electrical means adapted to shift said member to reversing position, and a pressure-responsive switch operatively connected to said cushion and adapted to be operated to control the actuation of said electrical means in response to the attainment of said predetermined pressure-upon said cushion.

2. In combination in a press, a movable platen, a hydraulic cylinder-and-piston assembly adapted to move said platen. a cushion adapted to be actuated by said platen, a member adapted to reverse the movement of a fluid, electrical means adapted to shift said member to a reversing position, a switch adapted when operated to energize said electrical means to shift said member to a reversing position, and a hydraulic plunger connected to said cushion and adapted to operate said switch to energize said electrical means and shift said member to reversing position in response to the attainment of a predetermined pressure upon said cushion whereby to reverse the direction of travel of said platen in response to its causing a predetermined pressure to be exerted upon said cushion.

3. In combination in a press, a movable platen, A

a source of pressure fluid, a hydraulic cylinderand-piston assembly adapted to move said platen, a member adapted to reverse the movement of the iiuid, a cushion adapted to be actuated by said platen, between said source and said assembly, electrical means adapted to shift said member to a reversing position, a switch adapted when operated to energize said electrical means to shift said member to a reversing position, and a hydraulic plunger connected to said cushion and having yielding means associated therewith arranged to oppose the shifting of said plunger when acted upon by the pressure uid transmitted thereto from said cushion, said plunger being adapted to operate said switch to energize said electrical means and shift said member to reversing position in response to the attainment of a predetermined pressure in said cushion sufcient to overcome the opposition of said yielding means whereby to reverse the direction of travel of said platen in response to its causing a predetermined pressure to be exerted upon said cushion.

HOWARD F. MAcMILLIN.

DON C. YOUNGBLOOD.