US2009487A - Hydraulic press - Google Patents

Description

July 30, 1935. w. ERNST ET AL HYDRAULI C PRE S S Filed July 13, 1931 5 Sheets-Sheet l -libliw m a t m w w a. w M h N\ m n u July 30, 1935. w. ERNST ET AL HYDRAULIC PRES 5 Filed July 13, 1951 5 Sheets-Sheet 2 km mm m Q m &. r lllllllll IL kw W: mm N v W am wXQ wm 0 M\\ Q. W W \Q o m 3nventors.

July 30, 1935. w. ERNST El AL HYDRAULI C PRES S Filed July 13, 1931 5 Sheets-Sheet 3 fiez'a'fsr YZaresora,

- July 30, 1935. w. ERNST El AL HYDRAULI C PRES S Filed July 13, 1931 5 Sheets-Sheet 4 3|?ntors, 7Z6 4 I307 0 attorneys July 30, 1935. W. ERNST El AL HYDRAULIC PRESS Filed Jul 'ls, 1931 5 Sheets-Sheet 5 Gttoruegs,

Patented July 30, 1935 UNITED STATES PATENT OFFICE hi0, assignors to The Hydraulic Press Manufacturlng Company, Mount Gilead, Ohio Application July 13, 1931, Serial No. 550,558

14 Claims.

' This invention relates to presses or the like, and more particularly to presses of the kind provided with a reciprocatory ram equipped with a platen, die, punch, or other tool and with a table or other means for positioning material or articles to be worked upon in the path of the platen or other equipage and for subsequently withdrawing the table and positioning it accessibly for removal of the completed work and for reception of another charge of material or article to be worked upon.

Presses of this general description are well known in the art, and for an example thereof reference may be had to United States Patent 1,778,803, granted to Leslie S. Hubbert, October 21, 1930. In the press shown in the patent referred to, a platen is fixed to a hydraulic ram arranged to move the platen towards a press head for performing pressing operations.

Mounted on the platen is a slidable table arranged to be moved into or out of the path of the platen by means of a hydraulic piston connected to the table. In the press shown in the patent, as well as in other presses of this general character heretofore known in the art, separate means are provided for controlling the movements of the platen, and of the slidable table. In operation, with the platen in its retracted position, a table-controlling valve is opened in order to efiect application of pressure to the hydraulic piston to move the table with the work thereon into the path of the platen and subsequently a ram-controlling valve is opened to effect application of pressure to the ram to produce a pressing stroke of the platen. After the pressing stroke has been completed, the ramcontrolling valve is moved to a position efiecting a return of the platen to its retracted position, and then the table-controlling valve is moved to a position effecting movement of the table out of the path of the platen to permit removal of the completed work. It will be noted that to effect a complete operating cycle of a press of this kind it is necessary for the operator to make four separate settings or adjustments of the valves. The overall operating time for each cycle therefore varies in accordance with the skill of each individual operator, and, in most cases, the maximum production of which a given press is capable is not obtained.

The main object of the present invention is to provide, in a press of the general character set forth above, means controlling the movements of the work positioning table, and automatically controlling the movements of the press ram to effect a pressing stroke thereof when the table is moved into the path of the ram.

Among the several other objects of the invention are to provide means for automatically effecting a movement of the work positioning table 5 into the path of the platen when the latter reaches the end of a return stroke; to provide means for causing the platen either to perform an indeterminate number of working strokes while the table remains in a given position or 10 to perform only one such stroke and then to come to rest in its retracted position, as may be desired; and to provide means for readily adapting the press for operation inaccordance with the varying requirements of the particular opera tion to be performed. Other objects will become apparent from a reading of the following description, the appended claims, and. the accompanying drawings, in which:

Figure 1 is a view in side elevation of a press 20 embodying the invention with the top of the press broken away and with certain control mechanism being shown in section;

Figure 2 is a. view in front elevation of the press shown in Figure 1, certain control mecha- 25 nism being shown in section;

Figure 3 is a fragmentary view in side elevation of the press shown in Figure 1, and showing the opposite side of the press from that shown in Figure 1, certain control mechanism being shown 30 in section;

Figure 4 is a fragmentary vertical sectional view taken on the line 4-4 of Figure 1 and drawn on an enlarged scale;

, Figure 5 is a fragmentary vertical sectional 35 view taken on the line 5-5 of Figure 3 and drawn on an enlarged scale;

Figure 6 is a fragmentary vertical sectional View taken on the line 6-6 of Figure 4;

Figures 7 and 8 are vertical sectional views of 0 a ram control valve and showing a piston valve element thereof in diiTerent positions;

Figure 9 is a diagrammatic showing of an electrical control circuit for the press ram;

Figure 10 is a diagrammatic showing of an elec- 45 trical control circuit for the work positioning tables;

Figure 11 is a view in side elevation of a press embodying the invention in modified form, certain control mechanism being shown in section; 50

Figure 12 is a detail view in vertical section of an automatically operable air valve.

Figure 13 is a detail vertical sectional view taken on the line l3-l3 of Figure 1; and

Figure 14 is a view in vertical section of a. table- 66 controlling valve, with the piston valve thereof in a different position from that shown in Figure 1.

The invention may be embodied in various kinds of hydraulic motors, but for the purposes of illustration is shown as embodied in a hydraulic press A of the downward pressure type having a base I, a head 2 connected to the base by means of side frame elements 3, and a platen 4 mounted in guides 5 for reciprocatory movements with respect to the base and the head. For reciprocating the platen there are provided cylinder means including a pressing cylinder 6 having a work chamber I and push-back cylinders 8 having return chambers 9, and ram means connected to the platen and including a pressing ram I!) mounted for reciprocation in the pressing cylinder, and return rams mounted for reciprocation in the push-back cylinders 8.

The base is provided with extensions l2 and I3 which project forwardly and rearwardly from the base respectively and which, together with the central or intervening part of the base, form a support for two slidable tables l4 and I5 connected together as at I6 and constrained for sliding movements into and out of the path of the platen by means of guides I1 and I8.

In operation, assuming the parts to be in the positions shown in Figures 1, 2, and 3, wherein the platen is at dwell in its uppermost position and the table I5 is positioned at the rear of the press, the operator will position the material or article to be pressed upon the table l5 and will then, in a manner to be described, cause the tables to be moved together to the left as viewedin Figure l and to the right as viewed in Figure 3, thereby positioning the table l5 in the path of the platen. After this the ram will be caused to descend to perform the pressing operation and to then return to its upper position. During the movement of the ram, the operator may load or change the table M which, it will be observed, will at this time be positioned at the front of the press over the extension I2 and accessible to the operator. To perform a pressing operation on the material thus placed on the table l4, the tables will be moved to their starting positions and the ram will be caused to operate as before. Control mechanism for effecting the desired operation of the tables and ram in accordance with various requirements will be hereinafter described.

The hydraulic circuit for operating the press ram and the means for controlling fluid flow in this circuit is similar to those shown in the patent to Walter Ernst, No. 1,927,583, granted Sept. 15, 1933. For supplying fluid under pressure to the work chamber and to the return chamber to reciprocate the platen we provide a pump B, a tank or reservoir C, a reversing ram-controlling valve D, and suitable piping forming, with the work and return chambers, the pump, the tank and the valve, a reversible flow hydraulic circuit.

The valve D includes a casing I9 formed with a valve chamber 20, and a piston valve 2| mounted for sliding movements within the casing. The piston valve comprises spaced heads 22, 23, and 24, a valve stem 25 interposed between and connecting the heads 22 and 23, and a stem 26 interposed between and connecting the heads 23 and 24. A passage 21 formed within the piston valve provides constant communication between the space defined by the valve casing and the heads 22 and 23 and the space defined by the valve casing and the heads 23 and 24. A valve rod 28 extends from the head 22 through the adjacent end of the casing l9 for connection to valve actuating means to be later described.

The piping connecting the reversing valve, the tank, and the pump to complete the reversible flow circuit includes a pump intake or suction pipe 29 respectively communicating at its opposite ends with the pump and the tank, a discharge pipe 30 communicating at one end with the pump and at its other end with the valve chamber 20, adjacent to the center thereof, a pipe 3| which connects the work chamber 1 of the main cylinder with the valve chamber at a point between the pipe 30 and the left hand end of the valve as viewed in Figures 2, '7, and 8, a pipe 32 which connects the return chambers 9 of the push-back cylinders with the valve chamber adjacent the right hand end thereof, an exhaust pipe 33 connected to the tank C and exhaust branches 34, 35, and 36 respectively, communicating with the valve chamber, as shown in Figures 2, 7, and 8.

Thus far only the press and associated hydraulic circuit have been described and no means have been described for actuating the valve D to control the movements of the platen. In order to assist in the understanding of the detailed description of the control means which is to follow, the operation of the press will be briefly set forth without reference to any particular means for shifting the valve.

Assuming that the parts are in the relative positions shown in Figures 1, 2, and 3, the pump will receive fluid through the suction pipe 29 and will discharge fluid under pressure through the pipe line 30 into that part of the valve chamber 20 then included between the valve heads 22 and 23. This fluid will then pass through the passage 21 in the piston valve to the space between the valve heads 23 and 24 and thence to tank C by means of the branch exhaust pipe 35 and the exhaust pipe 33, the pump discharge being thus by-passed so as to produce no movement of the press platen. When the piston valve 2| is moved to its extreme left hand position (the position shown in Figure 7), discharge from the pump will flow through the discharge pipe 30 into that part of the valve chamber then included between the heads 22 and 23 and thence through the pipe 3| to the work chamber 1. At this time the return chambers of the push-back cylinders will communicate with the tank C by means of the pipe 32, that part of the valve chamber then included between the head 34 and the right hand end of the valve casing, the exhaust branch 36, and the exhaust pipe 33. Fluid under pressure entering the work chamber will then move the platen downwardly to perform apressing operation, this downward movement of the platen and consequently of the push-back rams forcing from the return chambers 9 the fluid which remained therein after the termination of the preceding return stroke. When the working stroke has been completed, the valve 2| will be moved to its extreme right hand position (the position shown in Figure 8), at which time the pump will deliver fluid under pressure to the push-back cylinders by means of the discharge line 30, that part of the valve chamber then included between the heads 22 and 23, the passage 21 in the piston valve 2|, that part of the valve chamber then included between the heads 23 and 24, and the pipe 32. Fluid under pressure thus delivered to the push-back cylinders will cause the platen to move upwardly which will result in expelling from the work chamber the fluid remaining therein at the completion of the preceding working stroke, this fluid passing back to the tank through the pipe 3|, that part of the valve chamber included between the head 22 and left hand end of the valve casing, the exhaust branch 34, and the exhaust pipe 33. When the platen has been thus returned to its uppermost position, the valve 2| may be moved either to its Figure 7 position to start another working stroke, or to its Figure 2 position to bring the platen to rest.

From the foregoing it will be observed that the valve 2| is movable to three positions respectively to direct fluid under pressure to the work chamber 1 to effect a working stroke, or to the return chambers 9 to effect a return stroke, or to cut off fluid flow to both the work and return chambers simultaneously.

For moving the valve 2| from either its Figure 2 or its Figure 8 position to its Figure 7 position to eifect a pressing stroke of the platen, we have provided electrical valve-actuating means generally designated E and comprising a solenoid 31 having a plunger 38 connected to the valve rod 28 through the medium of a link 39 pivoted at its lower end to the plunger 38 as at 40 and pivoted at its upper end as at 4| to a forked crank arm 42 secured to a rock shaft 43 journalled in brackets 44 on the side frame of the press, and a link 45 pivoted at one of its ends as at 46 to the valve rod 28 and pivoted at its other end as at 41 to a forked crank arm 48 also secured to the shaft 43. When the solenoid is energized in a manner to be hereinafter described, the plunger 38 will be drawn downwardly which, through the link 39 and the crank arm 42, will rock the shaft 43 in a clockwise direction. This rocking of the shaft will swing the arm 48 in a clockwise direction and will move the valve rod 28 and the valve 2| to the left to their Figure 7 positions, thus initiating a pressing stroke. It will be observed that the solenoid 37 and valve D together constitute electrically actuated flow-controlling means. Any other suitable form of electrical device having a movable element connected to the valve rod 28 may be used instead of the solenoid 31.

For constantly urging the valve 28 to its extreme right hand or Figure 8 position, there is provided a spring 49 interposed between a lug 50 on the press frame and an arm 5| secured to the shaft 43, this spring tending torotate the shaft 43 in a counter-clockwise direction, and to move the valve 2| to its Figure 8 position.

In accordance with the invention, control means is provided for either automatically energizing the solenoid when the platen approaches the end of a return stroke, for automatically energizing the solenoid when one or the other of the tables 4| 5 is moved into the path of the platen, or for manually effecting energizing of the solenoid when the platen is at rest in its upper position; and for automatically eflecting deenergizing of the solenoid when a predetermined degree of pressure is built up in the work chamber 1 during a pressing stroke, the deenergizing of the solenoid permitting the spring 49 to return the valve to its Figure 8 position to start a return stroke. This control means includes a rod 52 mounted for vertical sliding movements in lugs 53 and 54 on the press head and base respectively, the rod 52 being urged downwardly by means of a spring 55 interposed between the lug 53 and a collar 55 secured to the rod, and being limited in its downward movement'by a collar 51 secured to the rod and adapted to engage the lug 54. Mounted on the platen is an arm 58 having at its outer end a boss 59 through which the rod 52 extends and with respect to which the rod is freely slidable. During upward movement of the platen, the boss 59 is adaptedto engage a collar 60 secured to the rod in adjusted position. After this engagement of the boss 59 with the collar 60, further movement of the platen will raise the rod, and will move the valve 2| toward its Figure 2 position through medium of a forked arm 6| secured to the shaft 43 and engageable by a collar 62 secured to the rod 52. When the rod is lifted the collar 62 will engage the arm 6| and will rock the latter in a clockwise direction, thus moving the valve 2| from its Figure 7 position to the right. As the platen approaches its uppermost position the valve 2| will, by means of the mechanism just described, be caused to gradually approach its Figure 2 position. During this movement of the valve, the head 23 will gradually uncover the exhaust branch pipe 35 so that the by-pass to the tank will be gradually opened. At the same time the head 24 will gradually cover the end of the pipe 32. The return motion of the platen will cease as soon as the throttled exhaust opening between the valve chamber and the exhaust branch 35 is enlarged to such a degree that the pump pressure has dropped to a value required to balance the weight of the movable press elements. At this time a state of balance will exist in the circuit and the pump will supply fluid at a pressure just suflicient to hold the movable press parts in their upper position against the attraction of gravity. Although, when the platen is automatically brought to rest in its upper position, the valve 2| will not be moved all the way from the Figure 8 to the Figure 2 position, it is obvious that in the position to which the valve will be moved in'actual practice flow of fluid under pressure is effectively cut off from both the work and return chambers. A manually operable lever 53 secured to the shaft 43 provides for manual control of the press whenever desired.

In some cases, where the reversing valve is necessarily heavy because of the high pressures handled, the force required to move the valve may be greater than that available from the solenoid 31 and the spring 49. In such cases the reversing valve may be actuated by means of an auxiliary hydraulic pilot circuit including a Servo Motor for effecting the application of pressure to suitable pistons or plungers for'moving the main valve to each of its three positions. Devices of this kind are well known in the art and need not be here further referred to.

The solenoid 31 is adapted to be connected to a suitable source of electrical power by means of power lines 64 and 65,'and a two-pole normal- 1y open main switch F which includes switch arms 66 and 61 adapted to be closed upon switch points 68 and 69 to close the circuit through and to energize the solenoid. The arms and 61 of the main switch are fixed to a rotatable shaft 70 urged in the direction of the arrow :1: in Figure 9 by means of a spring 1| connected to an arm 12- on the shaft, the switch arms 65 and 67 being thereby normally maintained out of contact with the points 68 and 69. The shaft 10 is adapted to be rotated in the direction of the arrow 1 and the main switch consequently adapted to be closed by electric means comprising a pilot electric circuit connected across the line 64 and 55 and including three parallel circuit branches 13, I4, and 15, a circuit portion I6 common to all of the branches and connecting one end of each to the line 05, and a conductor 11 also common to all of the branches and being adapted to connect one end of each to the line 84.

Interposed in series in the circuit portion I6, which, it will be noted, is exterior of all of said branches, is a manually operable cut-out switch 18 or selector device and a holding coil 19, the latter when energized being adapted to attract an arm 80 fixed to the shaft 10 as at 8I and to thus rotate the shaft to close the main switch and to energize the solenoid. When the holding coil 19 is energized the arm 80 will be swung in the direction of the arrow 11 (see Figure 9), at which time a normally open contactor switch G will be closed, the switch G comprising a contactor bridge piece 82 on the lower end of the arm 80 adapted to bridge two contact points 83 and 84, thus connecting the circuit branch 13 with the conductor 11 and completing the pilot circuit through the branch I3. The shaft 10 and the arm 80 are urged to their Figure 9 positions by the spring II.

The circuit branch 13 includes a conductor 85 connected to the circuit portion 16, a normally closed emergency reverse push button switch 86, a conductor 81, a normally closed pressure responsive switch 88, and a conductor 89. The switch 88 includes a switch arm 90, spring urged to its closed position, and an operating arm 9| mounted in fixed relation to the switch arm 90. This switch is adapted to be opened by means of a rod 92 mounted on a piston 93 arranged for sliding movements in a cylinder 94 mounted on the press head. The piston 93 and the rod 92 are urged to the left as viewed in Figures 2 and 9 by means of a spring 95 interposed between the piston and a nut 96 by means of which the compression of spring 95 may be adjusted. The chamber within the cylinder 94 is in constant communication with the work chamber I through the medium of a pipe 91 so. that the pressure within the cylinder 94 will always be equal to that in the work chamber. The compression of the spring 95 is so adjusted that the piston 93 will remain in its extreme left hand position as shown in Figure 2 until a desired predetermined pressure has built up in the work chamber and in the cylinder 94 during a working stroke, at which time the piston 93 and the rod 92 will be moved to the right against the action of the spring 95, the rod 92 at this time engaging the operating arm 9I of the switch 88 and moving it to rockthe switch arm 90 in a clockwise direction. This opening of the switch 88 serves to break the pilot circuit through the circuit branch 13, thereby deenergizing the coil 19 and effecting opening of the main switch to deenergize the solenoid also. This permits the spring 49 to move the valve 2I to its Figure 8 position and to start a return stroke of the platen.

It will be observed that when the holding coil 19 has been once energized and the bridge piece 82 closed upon the contact points 83 and 84 in the manner already described the pilot circuit will be closed through the conductor 11, the circuit branch I3, and the common circuit portion I6, thus maintaining the coil 19 energized and maintaining the bridge piece 82 closed upon the points 83 and 84 until either the switch 86 or the switch 88 is opened.

The circuit branch 14 includes the conductor 85, a normally open manually operable starter switch 98 preferably of the push-button variety, and a conductor 99 connected to the common conductor ll. Assuming that all of the circuit branches are open as shown in Figure 9 and that it is desired to momentarily manually energize the holding coil 19 to close the main switch and to close the bridge piece 82 upon the points 83 and 84, the push-button switch 98 is pressed, thus closing the pilot circuit through the common circuit portion Hi, the conductor 85, the switch 98, the conductor 99, and the conductor 11. As soon as the holding coil is thus energized the pilot circuit will be closed through the circuit branch 13 in the manner described above and subsequent opening of the push-button switch 98 will not act to deenergize the holding coil 19 or to open the main switch.

It is sometimes desirable that the platen perform an indeterminate number of pressing operations or impart a number of blows upon a single charge, that is to say, perform a number of successive operations while the work positioning tables remain in one position. In order to render such operation available means are provided for automatically effecting a closing of the main switch F to energize the solenoid when the platen approaches the end of a return stroke. To this end the circuit branch 15 includes a conductor I connected to the common circuit portion 16, a manually operable selector switch IOI, a conductor I02, a normally open switch I03 having a switch arm I04 spring urged to open position, a conductor I05, and a conductor I06. A collar I0'l secured to the platen operated rod 52 is adapted when the rod is lifted in the manner already described to engage an operating arm I08 mounted in fixed relation to the switch arm I04 to move the latter to its closed position, thus completing the pilot circuit through the circuit branch "I and energizing the holding coil I9 which, as stated above, effects closing of the main switch and energizing of the solenoid. When the platen begins another pressing stroke with the resultant lowering of the rod 52 and opening of the switch I03, the holding coil will maintain the bridge piece 82 closed upon the contact points 83 and 84, thus maintaining the main switch F closed and the solenoid energized until the pressing stroke has been completed and the switch 88 opened in the manner already described.

An important feature of the invention consists in the provision of means for automatically initiating a pressing stroke of the platen when one or the other of the tables I4--I5 is moved under the platen. To this end the pilot circuit shown in Figure 9 is provided with a shunt circuit portion I09 including a conductor IIO, a normally open table-operated switch III, and a conductor I I2 which is connected to the conductor I05 previously referred to.

The switch I I I is mounted in an opening in the table guide I! as shown in Figure 4, and includes a fixed contact point H3 and a movable element comprising upper and lower arms II4II5 respectively which are normally maintained out of contact with the point II3 by means of balanced springs I I6-I I6. An operating arm II! is fixed to the movable element II4I I5 and is adapted to be engaged by a roller II8 on a pin II9 carried by a slide I20 mounted in a box-like guide I2I secured to the base I of the press alongside of the table slide-way as shown in Figures 1, 2, 4, and 6.

The slide I20 extends through both ends of the guide I2l, and is provided at its opposite ends with bolts I 22-l 23 which serve to vary the effective overall length of the slide. The bolt I22 is disposed in the path of and is adapted to be engaged by a lug I24 on the table I4 when the tables are moved to the right as viewed in Figure 6 to thereby cause the slide I20 to be moved to the right. Similarly, the bolt I23 is disposed in the path of and is adapted to be engaged by a lug I25 on the table I5 when the tables are moved to the left as viewed in Figure 6 to thereby move the slide to the left.

Assuming the parts to be in the positions shown in Figures 1, 4, 6, and 9, with the tablesat the right, if it is desired that movement of one or the other of the tables under the platen automatically effect a single pressing and return stroke of the platen, the selector switch IOI will be-opened, and the tables I4 and I5 will then be moved to the left in a manner to be described to bring the table I5 under the platen, resulting in engagement of the lug I25 with the bolt I23 on the slide I20, and movement of the slide to the left. As the roller II8 on the slide passes the switch III, the roller will contact with the operating arm In of the switch, momentarily moving the latter to the left to cause the lower arm II5 of the switch to close upon the fixed contact point I I3, thereby completing the pilot circuit through the circuit branch 75 and the shunt circuit branch I09. This will effect closing of the main switch F and energizing of the solenoid E, shifting of the piston valve 2| of the valve D to its Figure 7 position, and a downward movement of the ram and platen in'the manner already described. The platen will then perform a complete pressing stroke and will be returned to its upper position in the manner heretofore described, after which it will be brought to rest. When the tables I4 and I5 are returned to their right hand position, the lug I24 on the table I4 will engage the bolt I22, moving the slide I20 to the right. As the roller II8 passes the operating arm III, the latter will be deflected to the right as viewed in Figure 9, thereby closing the upper arm II4 of the switch upon the fixed contact II3, thus closing the pilot circuit through the circuit branch I5 and shunt circuit branch I09, and energizing the solenoid in the same manner as before. The platen will then perform another complete pressing and return stroke, after which it will come to rest in its upper position.

If it is desired that the platen perform a number of pressing strokes upon a given piece of work and without any intervening movement of the tables, the switch I M will be closed. This will immediately close the pilot circuit through the circuit branch I5, closing the main switch F and energizing the solenoid E. The platen will then perform a complete pressing and a return stroke. As the platen apprcaches the end of the return stroke, the boss 59 will engage the collar 60 on the rod 52 and will lift the lat-. ter, causing the collar I01 to engage the operat-.

ing arm I08 of the switch I03 to close the latter. This will automatically close the pilot circuit and close the main switch F, resulting in energizing of the solenoid E and performance of another working stroke. The platen will continue to perform working and return strokes automatically until the switch I is opened, rendering closing of the switch I03 ineifective.

It will be noted that the table-operated switch III constitutes means associated with the work positioning tables and automatically operable upon movement thereof for operation of the ram-controlled valve D to effect application of force to the ram to cause the latter to perform a working stroke.

Through the closing or opening of the manually operable selector switch IN, the closing and opening of the switch I03 in the circuit branch 15 will be rendered effective or ineffective as desired, that is to say, when the switch IN is closed the closing of the switch I03 will automatically effect energizing of the solenoid when the platen approaches the end of a return stroke, whereas, when the switch MI is open, the closing of the switch I03 will be ineffective and pressing strokes of the platen will be initiated only upon one or the other of the tables I4I5 being moved into position under the platen, upon manual closing of the push button starter switch or manual operation of the lever 63.

Referring now to the means for moving the tables I4 and I into and out of the path of the platen, and to the control means therefor, a piston rod I26 connected to the table I5 extends rearwardly therefrom and is provided at its outer end with a double acting piston I21 mounted to slide in a cylinder I28. A pump H is provided for supplying the opposite ends of the cylinder I28 with fluid under pressure for moving the piston I21 and the .tables I4 and I5 in both directions. The pump is connected to a tank I by means of a suction pipe I29, and is adapted to discharge fluid under pressure through a delivery pipe I30 connected to a control device or table-controlling valve J.

The valve J includes a casing I3I defining a valve chamber I32 and a piston valve I33 mounted for sliding movements in the valve chamber. The piston valve comprises spaced heads I 34 and I35 connected by a reduced portion I36, and a long stem I31 extending through one end of the valve casing and being guided in a lug I38 on the press base. Apipe I39 provides communication between the valve chamber and the rear or outer end of the cylinder I28, and a pipe I 40 provides communication between the valve chamber and the inner end of the cylinder. An exhaust pipe I4I provides communication between one end of the valve chamber and the tank I, and a branch exhaust pipe I 42 connected to the exhaust pipe I4I provides communication between the opposite end of the valve chamber and the tank I. V

In order to provide for manual operation of the valve J, levers I43 and I44 are pivoted to the press base at I45 and I46 respectively, and are pivotally connected to the stem I31 of the piston valve by means of links I41 and I 48.

In operation; assuming the parts to be in the positions'shown in Figures 1 and 3, and assuming that it is desired to move the table I5 under the platen, one or the other of the levers I43- I44 will be manually moved in a clockwise direc tion as viewed in Figure 3, thereby shifting the piston valveI33 to its Figure 14 position. The pump H will then deliver fluid under pressure through the pipe I 30 into that part of the valve chamber bounded by the heads I34 and I35,

thence through the pipe I39 to the outer end of the cylinder I 28, thereby moving the piston I 21 and the tables to the left as viewed in Figure 1 and to the right as viewed in Figure 3 to position the table I5 under the platen. While the piston I31'is being thus moved toward the inner end of the cylinder I28, fluid contained in the inner end of the cylinder will be returned to the tank I by means of the pipe I40, the outer end of the valve chamber, and the exhaust pipe I. In Order then to move the tables to bring the table I4 under the platen, one or the other of the levers I43--I44 is moved in a counterclockwise direction as viewed in Figure 3 to return the piston valve I33 to its Figure 1 and Figure 3 position. Fluid discharged by the pump H will then pass through the pipe I30, the valve chamber between the heads I34 and I35, the pipe I40 and into the inner end of the cylinder I28, thereby forcing the piston I21'and the tables I4 and I5 to the right as viewed in Figure l and to the left as viewed in Figure 3, thus returning the table I4 to its position under the platen. While the piston I21 is being thus driven to its outer position, fluid contained in the outer end of the cylinder I28 will be returned to the tank I through the medium of the pipe I39, the inner end of the valve chamber, the branch exhaust pipe I42, and the exhaust pipe I4I It will be observed that the valve J and the associated levers I43 and I44 constitute a manually operable control device for effecting single movements of the tables I4 and I5.

In accordance with a further feature of the invention, means are provided for automatically operating the valve J to institute a movement of the tables when the platen approaches a predetermined point during its upward travel. To this end two automatically operable control devices or solenoids K and K are mounted on the press base and are provided with movable plungers I49 and I50 respectively having pin and slot connection with depending arms I5I and I52 of the levers I43 and I44. When the solenoid K is energized, the plunger I49 thereof is moved to the left as viewed in Figure 3, thereby rocking the lever I44 in a clockwise direction and moving the valve stem I31 and the piston valve I33 to the right to its Figure 4 position. Similarly, when the solenoid K is energized, the lever I43 will be rocked in a counter-clockwise direction as viewed in Figure 3, thereby moving the valve stem I31 and the piston valve I33 to the left to its Figure 3 and Figure 1 position.

The solenoid K is adapted to be connected across the power line 64-65 by means of a double pole switch L which controls the energizing of the solenoid. The switch L comprises switch arms I53 and I54 mounted upon a shaft I55 urged in the direction of the arrow m by a spring I56. The switch L is adapted to be automatically closed when the tables have moved to the position shown in Figures 1 and 3. For accomplishing this purpose there is provided a pilot electric circuit connected across the power line 6465 and comprising a conductor I51; a table control means comprising a normally open platen operated switch I58; a conductor I59; a cut out switch I60, being one arm of a manually operable double pole switch IBI; a conductor I62; a tableoperated switch I63; a conductor I64; a holding coil I65; and a conductor I66 connected to the conductor 65 of the power line, all of the foregoing elements being connected in series across the line 64-65.

The platen operated switch I58 comprises a pivoted switch arm I61, a fixed contact point I68, and an operating arm I69 carried by the switch arm I61. The operating arm I69 is disposed in the path of a cam block I10 mounted on the upper end of a rod I1I fixed to the press platen.

The table operated switch I63 includes four fixed contact points I12, I13, I12, I13, and a rockable contact-making arm I16 pivoted centrally as at I11 and provided with an operating arm I 18. The switch I63 is mounted on the base I alongside of the table slide-way as most clearly shown in Figure 5, the operating arm I18 of the switch extending upwardly and being disposed in the path of a lug I19 on the table I5.

Assuming that the parts are in the positions shown in Figures 3, 5, and 10, with the exception that the switch I60 (Figure 10) is closed, and further assuming that the platen is moving upwardly, the tables will be automatically moved to bring the table I5 under the platen in the following manner. When the platen reaches a predetermined point during its upward travel, the cam block I10 will engage the operating arm I69 of the switch I 58, thereby closing the switch arm I61 upon the contact I68. The pilot circuit will then be closed through the conductor I51, the switch I58, the conductor I59, the switch I60, the conductor I62, the switch arm I16, the conductor I64, the holding coil I65, and the conductor I66. The holding coil being thus energized will attract an arm I on the shaft I55, thereby rocking the latter in the direction of the arrow N and closing the arms I53 and I54 of the switch L upon the associated fixed contacts. This will complete the circuit through the solenoid K, energizing the latter and rocking the lever I 44 in a clockwise direction as viewed in Figure 3, shifting the piston valve I 33 to its Figure 14 position, and thereby moving the table I5 under the platen in the manner described above.

After the table I5 has been moved under the platen in this manner, the platen will perform a pressing stroke and a return stroke in the manner already described. It is desirable that as the platen approaches the end of this return stroke the solenoid K be energized in order to move the valve stem I31 and the piston valve I33 to their outer positions, that is, the positions shown in Figures 1 and 3. To this end a separate pilot circuit is provided for automatically effecting connection of the solenoid K to the power line 64-65. This circuit is identical with that described for effecting the energizing of the solenoid K, and a detailed description thereof is not deemed necessary. The reference characters applied to the corresponding parts of the two pilot circuits are the same, with the exception that those applied to the circuit effecting energizing of the solenoid K are primed. i. e., the switch L corresponds to and operates in exactly the same manner as the switch L, the switch I58 corresponds to and operates in exactly the same manner as the switch I58, et cetera.

Assuming that the table I5 is under the platen and that the platen is approaching the end of its return stroke, the operating arm I18 and the switch arm I16 of the switch I63 will be in the positions indicated in dotted lines in Figure 10. As the platen approaches the end of the return stroke, the cam block I10 will engage the operat ing arm I69 of the switch I58, thereby closing the pilot circuit through the conductor I51, the switch I58, the conductor I59, the switch arm I60, the conductor I62, the switch arm I16, the conductor I64, the holding coil I65, and the conductor I66, thereby energizing the holding coil I65 and attracting the arm I80 to rock the shaft I55 in the direction of the arrow N. This will effect closing of the switch L and energizing of the solenoid K, whereby the lever I43 will be rocked in a counterclockwise direction as viewed in Figure 3 and the piston valve I33 moved to its outer position so as to direct fluid to the inner end of the cylinder I28 to thereby return the tables to the positions shownin Figures 1 and 3, wherein the table I4 is disposed under the platen. By opening the switch I 6| the closing of the switches I58-I 58' is rendered inefiective, it being noted that the switch I6I constitutes means whereby said table may be selectively adapted for either automatic or manually controlled operation.

It will be observed that the main ram I and the push-back rams I I-I I together constitute in efiect a double acting ram for reciprocating the platen.

Operation In order that the invention may be better understood, typical operating cycles of the press will be briefly reviewed.

If the character of the work is such as to make it desirable that both the ram and the tables be operated independently under separate manual control, the switch I8 in the circuit shown in Figure 9 and the switch IGI in the circuit shown in Figure 10 will be opened. Assuming the parts to be otherwise in the positions shown in Figures 1, 2, and 3, in order to start a pressing stroke of the platen, the control lever 63 will be moved in a clockwise direction as viewed in Figure 2, thereby shifting the piston valve 2| of the valve D to its Figure 7 position. Fluid will then be directed through the pipe 3| to the main cylinder 6, and the platen will be moved downwardly. When the desired pressure has been exerted the lever 63 will be rocked in a counterclockwise direction as viewed in Figure 2 to move the piston valve 2| to its Figure 8 position, thereby causing fluid to be directed through the pipe 32 to the push-back cylinders 8 and causing the platen to move on a return stroke. When a predetermined position has been reached during the return stroke, the boss 59 on the arm 58 will engage the collar 60 on the rod 52, lifting the latter until the collar 62 on the rod 52 engages the lever 42, rocking the latter in a clockwise direction as viewed in Figure 2 and returning the valve 21 to its Figure 2 position, whereupon the platen will be brought to rest. The lever I44 will then be rocked in a clockwise direction as viewed in Figure 3 to move the piston valve I33 of the table control valve J to its Figure 14 position, causing fluid to be delivered by the pump H through the pipe I39 to the outer end of the cylinder I28, and causing the piston I 2! and the tables to be moved to the right as viewed in Figure 3 to position the table I5 under the platen. The completed work may then be readily removed from the table I4 and a new charge of material placed thereon. The platen and tables may then be caused to perform the same cycles of operation through repeated manipulation of the lever 63 and of the lever I44 respectively.

If it is desired that the tables be operated under manual control, and that the platen be automatically operated so as to perform an indeterminate number of pressing operations without intervening movement of the tables, the switch |6| shown in Figure will be left open and the switches 78 and I 0| shown in Figure 9 will be closed. In order to initiate the first pressing stroke of the platen, the manually operable pushbutton switch 98 will be closed. This will effect energizing of the holding coil I9, closing of the main switch F, and energizing of the solenoid E in the manner already described. The plunger 38 of the solenoid will then be drawn downwardly, moving the piston valve 2| of the ram control valve D to its Figure 7 position, whereupon fluid will be directed to the main cylinder 6 and a pressing stroke will be performed. When a predetermined pressure has built up in the work chamber I, the piston 93 will be moved to the right to open the switch 88 to deenergize the holding coil I9, and to permit the main switch F to be opened, thereby deenergizing the solenoid E and permitting the spring 5| to move the piston valve 2| to its Figure 8 position so as to direct fluid under pressure to the push-back cylinders 8, and to produce a return stroke of the platen. When the platen approaches the end of its return stroke, the boss 59 will engage the collar 80, lifting the rod 52 until the collar I01 closes the switch I03. This will complete the pilot circuit through the circuit branch I5 and will effect energizing of the solenoid E and movement of the piston valve 2| of the valve D to its Figure 7 position in the manner described above, and another pressing stroke will be performed. Repeated pressing and return strokes will take place automatically until the switch I 0| is opened, after which closing of the switch I03 by upward movement of the platen will be rendered ineffective and the upward movement of the platen will move the piston valve 2| to its Figure 2 position, bringingthe platen to rest. The tables may then be shifted to bring the table I5 under the platen by manual operation of the lever I44 to move the piston valve I33 of the table-controlling valve J to its Figure 14 position.

If it is desired that the tables be operated under manual control, and that the platen automatically perform a pressing and return stroke upon a single movement of the tables, the switch |6| in Figure 10 will be left open, the switch I8 in Figure 9 will be closed, and the switch IIJI in Figure 9 will be opened. The lever I44 will then be rocked in a clockwise direction as viewed in Figure 3 to move the piston valve I33 of the valve J to its Figure 14 position to thereby move the table I5 under the platen. During this movement of the table, the lug I thereon will ongage'the bolt I23 and move the slide I20 to the left as viewed in Figure 6, thereby closing the switch I and completing the pilot circuit of Figure 9 through the circuit branch I5 and the shunt circuit branch I09. This will energize the holding coil I9 and will close the main switch F to energize the solenoid E and to move the piston valve 2| of the valve D to its Figure 7 position, thus starting a pressing stroke of the platen. The pressing and return strokes will then be performed in the manner previously described, and the platen will be brought to rest in its upper position. To effect another cycle of operation, the lever I44 will be rocked in a counterclockwise direction as viewed in Figure 3, thereby moving the tables I4 and I5 so as to position the table I4 under the platen. The lug I 24 will then move the slide I20 so as to close the switch III again to efiect energizing of the solenoid E and thereby to start another pressing stroke. It will be observed that the ram-controlled valve J constitutes common control means for the work positioning tables and for the ram means, since actuation of the valve automatically produces shifting of the tables and operation of the ram.

When it is desired that the movement of the tables automatically effect beginning of a pressing stroke of the platen and that return movement of the platen automatically efiect a shifting of the tables so as to provide for completely automatic and continuous operation of both the platen and the tables, the switch I8 shown in Figure 9 will be closed, and the switch IOI shown in Figure 9 will be opened. To start operation of the tables and platen the switch IIiI will be closed. Assuming the parts to be in the positions shown in Figures 1 to 10 inclusive, closing of the switch I6I will complete the pilot circuit through the holding coil I55, thereby closing the switch L and energizing the solenoid K. The plunger I49 of the solenoid K will be drawn to the left as viewed in Figure 3, thereby rocking the lever I44 in a clockwise direction and shifting the piston valve I33 to its Figure 14 position. Fluid under pressure from the pump H will then be directed through the pipe I38 to move the tables to the right as viewed in Figure 3 and to position the table I5 under the platen. During this movement of the tables, the slide I20 will be moved to the right as viewed in Figure 3 and to the left as viewed in Figure 6 to close the switch III, to energize the solenoid E, and to start a pressing stroke in a manner already described. Also during this movement of the tables, the lug I19 will engage the operating arm I18 of the switch I53, rocking the latter in a clockwise direction as viewed in Figures 3 and 10 and moving the switch arm I76 to its dotted line position to bridge the fixed contact points I12 and I13. After the pressing stroke has been completed and the platen is moving upwardly on a return stroke, the cam block I10 on the rod III will close the switches I58 and I58, thereby closing the pilot circuit through the holding coil I65, effecting closing of the switch L and energizing of the solenoid K. The plunger I50 of the solenoid will then be moved to the right as viewed in Figure 3, thereby rocking the lever I43 in a counterclockwise direction and returning the piston valve I33 to its Figure 3 position. Fluid discharged by the pump H will then be delivered through the pipe I40 to move the piston I21 and the tables to the left, positioning the table I4 under the platen. During this movement of the tables, the lug I19 on the table I5 will engage the operating arm I18 of the switch I62 to return the switch arm I16 to the full line position shown in Figure 10, and the slide J20 will again be operated to close the switch II to start another pressing stroke. After the completion of the pressing stroke and of the succeeding return stroke, the cam block I10 will close the switch I58 to effect closing of the switch L and energizing of the solenoid K, whereupon the tables will again be moved to the right as viewed in Figure 3 to bring the table I5 under the platen, and the platen will start to perform a pressing stroke as already described. The rain and tables will continue to operate in the foregoing sequence until either the switch 15, the emergency push-button switch 88, 'or the switch IBI is opened.

Figures 11 and 12 show a modified form of the invention in which a reversible flow hydraulic circuit is employed for reciprocating the platen and in which pressure actuated means is used for automatically reversing the direction of fluid travel in the circuit upon movement of the tables instead of the electrical means described above.

The press, shown in Figure 11, is the same as that already described, so that a description thereof is not considered necessary.

The fluid delivered to the chambers in the cylinders 6 and I is furnished by a reversible radial pump M, for example, of the kind known in Patent No. 1,250,170 to Hele-Shaw, et al. Generally speaking, in such pumps the direction of travel of the fluid discharged may be reversed by reciprocating the cross-head or similar device from one position to another. This cross-head is connected to a floating ring which, by movement of 4 struction of the pump in further detail, and suchconstruction is, therefore, not illustrated in detail herein, since the present invention relates to novel control mechanism interposed between the pump and the press whereby the operation of the pump will be controlled through the shifting of the tables from one position to the other and vice versa.

Means forming a reversible flow hydraulic circuit with the pump and press includes a pipe line I8I connected between a pipe connection I82 0n the pump and the ram return chamber 9 of the cylinders 8, and a pipe line I83 connected between a pipe connection I84 of the pump and -the work chamber I in the cylinder 6. When the pump is set to discharge through the pipe I83, fluid will be delivered to the work chamber 1 of the cylinder 6, thereby driving the ram and platen downwardly. At this time fluid contained in the return chambers 9 of the cylinders 8 will be expelled therefrom and drawn into the pump through the pipe I8I. versed so as to discharge through the pipe I8I, fluid will be delivered through this pipe to the return chambers 9, thereby moving the platen upwardly and fluid contained in the work chamber l of the cylinder 6 will be expelled therefrom, being drawn in by the pump through the pipe I83.

The pump shown is provided with mechanism generally designated N for moving the pump cross-head in both directions to reverse the direction of fluid flow through the pump and circuit, the mechanism end being of the kind shown, described and claimed in the patent to Walter When the pump is re-.

Ernst and Howard F. MacMillin, No. 1,937,192

granted November 28, 1933. This mechanism is described in detail in that patent, and for the purposes of the present disclosure, it will be necessary only to describe certain elements thereof. The mechanism includes a reversing control lever I85 pivoted as at I86 to a housing I8'I secured to the pump casing. This control lever is adapted to occupy two positions, being normally urged to the full line position indicated in Figure 11 and being adapted to be moved to the dotted line position through the medium of a power-operated device comprising a pressure operated piston I88 connected to the control lever by means of a piston rod I88 and mounted in a cylinder I90 carried by the housing I81.

As stated above, the lever I85 is normally urged to its full line position. In this position of the lever, the pump will discharge through the pipe I8I into the return chambers 9 to efiect a return stroke of the platen. When the lever is moved to its dotted line position, in a manner to be described later, it will be latched and retained in this position as further described in' the above named patent, the pump then delivering fluid through the pipe I83 to the work chamber I and eflecting a pressing stroke of the platen.

communicating with the tank I, a pipe I93 providing communication between the valve and the pipe I83, and a pipe I94 providing communication between the valve and the pipe I8I. Assuming that the pump is discharging through the pipe I93 during a working stroke, fluid will be drawn from the return chamber 9 through the pipe I94 This fluid, however, will not be suflicient alone to fill the more rapidly increasing volume of the work chamber, and the amount of fluid necessary to be added to the fluid removed from the returning chambers will be supplied from the tank I through the pipe I92 and the pipe I94. During a return stroke of the ram excess fluid from the work chamber will be returned to the tank I by means of the pipe I93, the compensating valve and the pipe I92.

When the platen reaches the end of a return stroke, the pump will continue to discharge fluid under pressure through the pipe I9I, and it is necessary that this pressure be relieved. To accomplish this purpose, a platen operated by-pass valve I95 of appropriate form such, for example, as that shown in the copending application, is connected between the pipe I8I and the tank I by means of a pipe I96 and a pipe I91. The bypass valve is provided with a long stem I99 which extends downwardly parallel to the direction of movement of the platen. Secured to the stem is a collar I99 adapted to be engaged by a lug 299 on the platen when the latter approaches the end of a return stroke, the valve stem I98'being thereby lifted to open communication between the inder I99 for moving the piston I89 to the left,

a tank 29I of compressed air or other fluid under pressure is adapted to be placed in communication with the cylinder by means of a pipe 292 connected to the cylinder, a table operated valve 293 located in a recess 294 in the press base, and a pipe 295 connecting the tank and valve. An exhaust pipe 296 provides for the exhausting of pressure fluid from the cylinder I99 when desired.

The valve 293 includes a valve casing 291 defining avalve chamber 299 and a piston valve 299 mounted to slide in the casing and being provided with a stem 2 I9 extending vertically upward and provided with a rounded upper end. A spring 2| I interposed between the piston valve 299 and the lower end of the valve casing constantly urges the piston upwardly, and an enlarged portion on the stem 2 I9 is arranged to abut the upper end of the valve casing and to limit the upper movement of the piston. The inner wall of the valve casing is formed with a recess 2I3 which extends longitudinally of the casing and which is not quite covered by the piston 299 in the normal position of the piston as shown in Figure 12, it being noted that the lower end of the recess projects slightly below the piston when the latter is in the position shown. The pipe 292 leading from the cylinder I99 communicates with the recess 2 I3, so that when the piston valve 299 is in its normal position, the cylinder I99 is in communication with the exhaust pipe 296. When, however, the piston valve 299 is moved downwardly, the piston will cut off communication between the pipe 292 and the exhaust pipe and will open communication between the pipe 292 and the pipe 295, thereby placing the cylinder I99 in communication with the tank 29I, and eflfecting movement of the piston I98 to the left to move the control lever I95 to the position shown in dotted lines in Figure 11.

In order that the piston valve 299 be automatically operated when the tables I4 and I5- are shifted, the stem 2I9 of the valve is arranged to project upwardly through a guide 2I4 which is similar in construction to the guide I2I shown in Figure 6 and described above. The rounded upper end of the stem 2| 9 is disposed for engagement with a roller 2 I5 mounted on a pin 2 I6 carried by a slide 2I1 which is provided at its opposite ends with bolts 2I8 and 2I9, the slide, roller and other associated parts being similar to those shown in Figure 6. When the slide 2II is moved to the left as viewed in Figure 12, the roller 2I5 will engage the upper end of the stem 2I9, thereby moving the latter and the piston valve 299 downwardly to momentarily provide communication between the pipes 295 and 292. After the roller passes the stem 2I9, the valve will be returned to its Figure 12 position by means of the spring H I. The same operation of the valve will take place when the slide 2I'I is returned to its Figure 12 position.

The means for moving the tables and I5 into and out of, the path of the platen is the same as the means shown and described in connection with the embodiment of the invention illustrated in Figures 1 to 10, inclusive, and it will be understood that these means may be controlled either manually or automatically as previously set forth.

Operation of modified form Assuming that the parts are in the positions shown in Figures 11 and 12, in order to eifect a complete operating cycle of the press, the piston valve I33 of the table control J will be moved to the left in the manner previously described, thereby causing the tables I4 and I5 to be moved to the left and the table I5 to be positioned under the platen 4. During this movement of the tables, the lug I25 on the table I5 will engage the bolt 2I9 on the slide 2II moving the latter to the left and causing the roller 2 I5 to engage and de- 7 press the valve stem 2I9 of the piston valve 299. This will cause the piston valve to move downwardly, to close communication between the pipe 292 and the exhaust pipe 296 and to open communication between the pipe 292 and the pipe 295. Fluid under pressure in the tank 29I will then flow through the pipe 295, the valve chamber 298, and the pipe 292 into the cylinder I99, thereby moving the piston I86 to the left where it will be latched in its dotted line position. After the roller 2I5 has passed the stem 2I9, the valve 299 will be returned to its upper position placing the cylinder I99 in communication with the exhaust pipe 296. Because of the control lever I95 being latched in position, it will remain in its dotted line position even after fluid has been exhausted from the cylinder I99.

The pump M will then deliver fluid through the pipe It! to the main cylinder and will effect a pressing stroke of the platen. when pressure builds up in the main cylinder and in the pipe I, the control lever "5 will be released. 1. e., unlatched and returned to its full line position, thereby reversing the direction of discharge of the pump and causing fluid to be delivered to the push-back cylinders 8 to effect a return stroke of the platen. When the platen approaches the end of the return stroke, the lug 200 will engage the collar I99 thereby lifting the valve stem I of the by-pass valve I95 and placing the pipe It! in communication with the tank I after which fluid will be by-passed to the tank and the platen will be maintained in its upper position.

In order to cause the press to perform another complete cycle of operation, the piston valve I33 01! the valve J will be returned to its Figure 11 position either manually or automatically, thereby causing the tables to be moved to the right to bring the table I under the platen. During this movement of the tables, the lug I24 on the table II will engage the bolt 2 l 8 on the slide 2 I I moving the roller 2 l5 toward the right into engagement with the stem 2) of the piston valve This will eiiect movement of the control lever I85 to its dotted line position in the manner described above, and the platen will perform another pressing and returning stroke.

Although the two forms of control means illustrated and described herein are considered practical embodiments of the invention, it will be understood that various changes may be made in the arrangement of parts without departing from the scope of the invention as defined in the appended claims.

We claim:

1. The combination with a press including a reciprocable ram, and a work positioning table mounted for movements into and out of the path of the ram; of means controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke of the latter; means for automatically effecting reversals of ram travel at the end of working strokes; and means responsive to movements of said ram for automatically effecting an indeterminate number of work positioning movements of said table.

2. The combination with a press including a reciprocable ram, and a work positioning table mounted for movements into and out of the path of the ram; 01 means controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke of the later; means for moving said table into and out 01' the path of said ram; a manually operable control device for said means and being operable to eflect single movements 01' said table independently of movement of the ram; an automatically operable control device for said means responsive to movement of said ram and being automatically operable to efl'ect an indeterminate number of movements of said table; and means for rendering said automatically operable control means inactive whereby said table may be selectively adapted for either automatic or manually controlled operation.

3. The combination with a press including a reciprocable ram, and a work positioning table mounted for movements into and out of the path or the ram; of means controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke of the latter; means for moving said table into and out of the path of said ram; a manually operable control device for said means and being operable to eflect single movements or said table independently of movements of the ram; an electrically actuated control device for said means; an electric switch in circuit with said electrically actuated device; means responsive to movement of said ram for automatically operating said switch to eflect actuation of said device; and a manually operable electric switch in circuit with said automatically operable switch and adapted, when open, to render operation of the latter ineffective, whereby said table may be selectively adapted for automatic or semi-automatic opera- 4. The combination with a press including a reciprocable ram, and a work positioning table mounted for movements into and out of the path of the ram; 0! means responsive to movement of the table for controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke of the latter; means for moving said table into and out of the path of said ram; an electrically actuated control device for said table-moving means; an electric switch in circuit with said device; and means responsive to movement of said ram for automatically operating said switch to eflect actua tion of said device.

5. The combination with a press including a reciprocable hydraulic ram, and a work positioning table mounted for movements into and out of the path of the ram; of hydraulic means for reciprocating the ram; hydraulic means for moving the table; an electrically actuated control valve device for said table-moving means; and an electric switch in circuit with said control valve device and being automatically operable by said ram when the latter approaches the end of a return stroke, to thereby effect actuation of said control device and movement of said table.

6. The combination with a press including a reciprocable ram, and a work-positioning table mounted for movements into and out of the path of the ram; of means for applying force to the ram for moving it to perform working strokes; electrically actuated means for controlling said force-applying means; an electric switch automatically operable by said table during movement of the latter for closing a circuit through said controlling means; and a selector switch in circuit with the table-operated switch and adapted when open to render operation of the latter ineffective.

'l. The combination with a press including a reciprocable ram, and a work-positioning table mounted for movements into and out of the path of the ram; 015 means for applying force to the ram for moving it to perform working strokes; means for controlling saidforce-applying means; means automatically operable by said table during movement of said table for actuating said controlling means; and a selector device cooperatively connected to said table-operated means and being adapted to render operation of the table-operated means ineffective.

8. The combination with a hydraulic press including a reciprocable double-acting ram, a workpositioning table mounted for movements into and outot the path of the ram, and a doubleacting hydraulic piston connected to said table for moving the latter in both directions; of means for supplying hydraulic pressure to said ram and piston; a ram-control valve for selectively directing fluid under pressure from said pressure supplying means to the respective sides of the ram; a table-controlled valve for selectively directing fluid under pressure from said pressure supplying means to the respective sides of the piston for moving the latter and the table; means operatively connected to said ram-control valve and associated with said table andbeing operable upon movement of said table for automatically moving said ram-control valve in one direction to direct pressure fluid to one side of the ram to effect a working stroke thereof; and means connected to said reversing valve and being responsive to the pressure acting on said ram for automatically moving said reversing valve in the opposite direction to direct pressure fluid to the other side of the ram to efiect a return stroke thereof.

9. The combination with a hydraulic press including a reciprocable double-acting ram; a workpositioning table mounted for movements into and out of the path of the ram, and a doubleacting hydraulic piston connected to said table for moving the latter in both directions; of means for applying hydraulic pressure to said ram and piston; a ram-control valve for directing fluid under pressure to the respective sides of the ram; a table-control valve for directing fluid under pressure to the respective sides of the piston; means associated with said table and being operable upon movement thereof for automatically moving said ram-control valve in one direction to direct pressure fluid to one side of the ram to effect a working stroke thereof; and means operated by the ram when the latter reaches a predetermined position during a return stroke for automatically moving said table control valve to eii'ect a movement or said table.

10. The combination with a hydraulic press including a reciprocable double-acting ram, a work-positioning table mounted for movements into and out of the path of the ram, and a doubleacting hydraulic piston connected to said table for moving the latter in both directions; of means for supplying hydraulic pressure to said ram and piston; a ram-control valve-tor selectively directing fluid under pressure from said pressure supplying means to the respective sides of the ram; a table-control valve for selectively directing fluid under pressure from said pressure supplying means to the respective sides of the piston for moving the latter and the table; an electrically actuated device operatively connected to said ram-control valve for moving the latter in a direction to direct pressure fluid to one side of said ram to eiiect the stroke thereby; and an electric switch in circuit with said device and being movable to closed position by said table when the latter is moved into the path of the ram for operating said electrically actuated device to move the ram-control valve in said direction to effect a stroke of said ram.

11. The combination with a hydraulic press including a4 reciprocable double-acting ram, 2. work-positioning table mounted for movements into and out of the path of the ram, and a doubleacting hydraulic piston connected to said table for moving the latter in both directions; of means for supplying hydraulic pressure to said ram and piston; a ram-control valve for selectively directing fluid under pressure from said pressure supplying means to the respective sides of the ram; a table-control valve for selectively directing fluid under pressure from said pressure supplying means to the respective sides of the piston for moving the latter and the table; electrically actuated means connected to said table-control valve for moving the latter in one direction; and an electric switch in circuit with said means and being automatically operable to closed position when the ram reaches a predetermined position during one of its strokes for operating said electrically actuated means and moving said tablecontrol valve in said direction to effect movement of said table.

12. The combination with a hydraulic press including a reciprocable double-acting ram, a work-positioning table mounted for movements into and out of the path of the ram, and a doubleacting hydraulic piston connected to said table for moving the latter in both directions; of means for applying hydraulic pressure to said ram and piston; a ram-control valve for directing fluid under pressure to the respective sides of the ram; a table-control valve for directing fluid under pressure to the respective sides 01' the piston; means associated with said table and being operable upon movement thereof in either direction for automatically moving said ram-control valve in one direction to direct pressure fluid to one side of the ram to effect a working stroke thereof; and means associated with said table-control valve and being automatically operable by said ram when the latter approaches the end of a return stroke for moving said valve to efl'ect a movement of said table.

13. Control mechanism for a press of the type including a reciprocable ram and a work-positioning table mounted for movements into and out of the path of the ram, comprising means for controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke of the latter; means for automatically eiIecting reversals of ram travel. at the end working strokes; and means responsive to movements of said ram for automatically efiecting an indeterminate number of working and return strokes of the ram without intervening movement of the table.

14. Control mechanism for a press of the type including a reciprocable ram and a work-positioning table mounted for movements into and out of the path of the ram, comprising means for controlling movement of the ram and being automatically operable by the table when the latter is moved into the path of the ram for initiating a working stroke 01' the latter; means for automatically effecting reversals of ram travel at the end of working strokes; means responsive to movements of said ram for automatically effecting an indeterminate number of working and return strokes of the ram without intervening movement of the table or for automatically eilecting sequential ram and table movements; and selector means for adapting said control mechanism for either kind of operation. 7

WALTER ERNST. REIDER THORESON.

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