US2472390A - Hydraulic press - Google Patents

Description

June 7, 1949. 2,472,390

F. 0. WILSON HYDRAULIC PRESS 2 Sheets-Shet 1 Filed July 25, 1944 INVENTOR.

ATTOFZVEY June 7, 1949. F. c. WILSON 2,472,390

HYDRAULIC PRESS Filed July 35, 1944 a sheets-sh et 2 Patented June 7, 1949 UNITED STATES PATENT OFFICE HYDRAULIC PRESS Frank C. Wilson, Arcade, N. Y. Application July 25, 1944, Serial No. 546,532

4 Claims.

This invention relates to improvements in hydraulic presses, and more particularly is concerned with a press of the kind adapted to utilize compressed air as the motive power.

One object of the invention is to provide a press which is designed so as to enable the development of a wide range of working pressures and which may be operated at high speeds with a minimum of control.

A further object is to provide a press which is controlled in such a manner that the pressures applied to the work may be accurately controlled and will be uniform as to similar operations.

A still further object is a press wherein provision is made for developing the required working pressures with a minimum of moving parts, thereby rendering the press particularly adaptable for shell-loading and other operations wherein any static produced constitutes a hazard.

A still further object is a novel design and arrangement of the parts of the press, whereby to obtain simplicity in construction, economy in operation and facility in control.

The invention is illustrated in the accompanying drawings in which:

Figure 1 is a view, partially in elevation and partially in section, of a press embodying the features of the invention.

Figure 2 is a sectional view of the pumping unit and is taken along line 22 of Figure 1'.

Figure 3 is an enlarged detail section taken along line 3-3 of Figure 2.

Figure 4 is an enlarged sectional view of the relay for controlling the flow of compressed air to the pumping unit.

The press is sufficiently indicated for the purpose in view by a showing of the working cylinder III, the latter being mounted in any suitable frame and having a piston II to which the ram I2, or other member to be actuated, is attached. A spring I3, which acts against the piston I I and a guide head I4, normally holds the ram I2 in a retracted position.

Liquid for actuating the ram is accommodated in a container [5 which carries a pump and motor unit I6. The latter includes a cylinder I! which is carried by a base section I8, mating flanges of the base section and a collar I9 being bolted or otherwise secured to a flange 20 on the top of the container I5. A barrel 2| is carried by the collar I9, being supported by the latter in axial alignment with the cylinder I1 and having its lower end immersed in the actuating liquid. A motor piston 22 is accommodated in the cylinder I1 while a pump piston 23 is accommodated in the barrel 2|, the two pistons being connected by a rod 24 and being normally held at the upper limit of their range of movement by a spring 25 which acts upon the under side of the piston 22 and the collar I9. At such upper limit a nut 25, which is employed to secure the piston 22 on the end of the rod 24,engages a spring-loaded pin 26a which provides a resilient stop.

At its lower end the barrel 2| (Figure 2) communicates with the container I5 through an intake port 21. A ball valve 28 permits actuating liquid to enter the barrel 2I but prevents the escape of such liquid from the barrel through said port. Actuating liquid may escape from the barrel through an outlet passage 29, past a ball valve 30 into a valve chamber 3|, a laterally extending passage 32 (see also Figure 1) which communicates with the valve chamber 3I terminating in an outletport 33. Actuating liquid escaping through said port may flow through pipes 34 and 35 to the working cylinder III.

In order to permit? return flow of actuating liquid to the container upon completion of the working stroke of the ram when the latter is being restored to its normal retracted position, a lower section of the pipe 34 carries a valve chest 36. An outlet port 31 in the latter is normally closed by a ball valve 38 while a secondary outlet port 39 is closed by a pressure-cracking valve 4|], the chambers occupied by the said valves communicating through a connecting passage H. The valves 38 and 40 may be opened by pins 42 and 43, respectively. A lever 44 which is pivotally connected to a wall of the valve chest may be actuated to elevate the pins 42 and 43, the pin 42 occupying a socket in the lever 44 and being normally held above a seat 45 and in yielding engagement with the ball valve 38 by a spring 46. The pin 43, on the other hand, seats solidly on the lever 44. Hence when the latter is lifted, the pin 42 will yield to insure prior opening of the valve 40 and thereby relieve the pressure in the valve chest. After this occurs, the seat 45 on the lever 44 solidly engages the actuating pin of the valve 38 and readily opens the latter.

A rod 41, which is connected at its lower end to the outer end of the lever 44, extends exteriorly of the container I6 through a sealed sleeve 41a. and alongside the base section and cylinder of the pump and at its upper end is connected to the lower end of a rod 48. The latter extends through an opening in a guide bracket 49 which is carried by the cylinder H, the rod 48 normally occupying a position corresponding to the closed positions of the valves 38 and 48, and being supported in such position by a spring 5I which is arranged around its upper end portion and between a head at its upper end and the guide bracket 49. A hand lever 52 for elevating the rod 48 to open the valves 38 and 48 is pivotally mounted upon a pin 53, in a channel 54 (Figure 2) formed in the under side of a cylinder head 55. A rod 56 which is connected at its lower end to therod 48 by a link 58 is connected at its upper end to the hand lever 52, a spring 51 which is arranged around the upper end of the rod 56 acting against the latter and the said lever to hold the lever in the normal, neutral position shown in Figure 1.

Compressed air for operating the press is supplied through a line 58, the air from the latter preferably first passing through a pressure regulator 59 and entering a supply line 68, a branch 6| of the latter leading to a relay valve 62, a branch 63 leading to an air inlet chamber 64 (Figure 3) in the cylinder head 55 and a branch 65 leading to an air inlet chamber 86 in the said head. An outlet port 6! in the chamber 64 is normally closed by a ball valve68 while an outlet port 69 in the chamber 66 is normally closed by a ball valve I8. A passage II with which the port 61 communicates terminates in an outlet 12 which communicates with an exhaust passage 13, a laterally extending passage I4, which communicates with the passage II intermediate the port 6! and outlet I2, being connected by a pipe 15 (Figure 1) with the container I5. A passage 16 (Figure 3) with which the port 69 communicates terminates in an outlet 17 and the latter communicates with an exhaust passage I8. A passage 19 which communicates with the passage 16 intermediate the outlet port 69 and outlet 11 is connected by a pipe 88 (Figure 1) to the lower side of the working cylinder I8.

A pin 8| for opening the valve 68 seats upon a plug 82 which is in the form of a saddle piece, the said plug occupying a bore 83 and straddling the lever 52 at one side of the pivot pin 53. A pin 84 for opening the valve I8 seats upon a plug 85 which is similar to the plug 82, which occupies a bore 86 and which seats upon the lever 52 at the opposite side of the pivot pin 53. A poppet valve 8'! is associated with each of the outlets I2 and H, the said valves occupying the bores 83 and 86 and resting upon springs 88 which, in turn rest upon the plugs 82 and 85. The parts are so designed that when the lever 52 occupies the neutral position shown in Figure 3, the upper ends of the pins 8| and 84 are located below their respective ball valves which are fully seated while the poppet valves 81 are unseated, it being understood in this connection that the pins BI and 84 pass through suitable bores in the poppet valves so as to permit free movement of pins and valves with respect to one another.

From the foregoing it will be apparent that by lifting the lever 52 the outlet I2 will be closed by its poppet valve and the ball valve 68 then elevated to permit air at a pressure fixed by the regulator 59 to pass from the supply line 58, pipe 68 and branch 63 thereof through the cylinder head 55 and pipe I5 to the container I5. As the pressure of the air over the actuating liquid builds up in the container I5, actuating liquid is delivered at such pressure through the pipe 35 to the working cylinder I8 and the ram I2 is moved toward and caused to engage the work against the action of the spring I3, it being noted in this connection that actuating liquid may enter the pipe 35 both by way of the inlet port 21 (Figure 2) in the pump barrel 2| and by way of the ports 31 and 39 (Figure 1) in the valve chest 36.

Referring further to Figure 1, it will be noted that a branch 89 of the pipe I5 communicates with a pressure chamber 98 (Figure 4) of the relay 62. The lower wall of the pressure chamber is provided by a flexible diaphragm 9I. The latter is engaged by the head of a stem 92 which in turn, is engageable with a ball valve 93 which under the influence of a spring 94 normally closes the entrance to a passage 95. The branch 6| of the air supply pipe 68 communicates with a chamber 96 in which the spring 94 and ball valve 93 are located while the passage 95 provides communication between the chamber 96 and an outlet port 91. A pipe 98 connects the port 97 to an inlet chamber 99 (Figures 2 and 3) in the cylinder head 55 of the pump I6. A passage I88 leads from the inlet chamber 99 to the pump cylinder I I above the piston 22 and also communicates through a port I8I with an exhaust outlet I82. A ball valve I83, which is associated with the port I8I, is normally held open by a pin I84 which seats upon the lever 52.

From the foregoing it will be apparent that when the lever 52 occupies its neutral position, the ball valves 88 and 18 will be closed so that compressed air from the supply line 68 cannot enter either the container I5 or the working cylinder I8. As the pressure in the inlet chamber 98 in the relay valve corresponds to the pressure in the container I5, the spring 94 will be operative at such times to hold the valve 93 closed and hence prevent the passage of compressed air into the pump cylinder II.

To actuate the ram I2, the handle of the lever 52 is lifted, thereby turning the lever in a counterclockwise direction about the pin 53. The spring 51 yields to permit the opposite end of the lever to slide down the rod 56 so that such movement of the lever will not be transmitted to the mechanism for controlling the relief valves 38 and 48. As the lever 52 is operated in the manner described, however, it opens the ball valve 68 while closing the associated poppet valve 87 and the ball valve I83. Hence compressed air is permitted to enter the container and act upon the actuating liquid therein. As the pressure builds up in the container actuating liquid is caused to flow through the pipe 35 to the working cylinder, thereby moving the ram I2 toward and into engagement with the work. When the pressure in the container approaches a predetermined value, the corresponding pressure in the chamber 98 of the relay valve 62 extends the diaphragm 9| to open the valve 93 and permit compressed air to enter the cylinder I! to actuate the booster pump. The piston 23 is thereupon operative to force the actuating liquid in the barrel 2I into the cylinder I8 to complete the working stroke of the ram, an opening I which is formed in the lower end of the base section I8 of the pump providing a vent through which air may escape from the cylinder II. Upon completion of the working stroke the handle of the lever 52 is depressed. As the lever in this reverse movement passes beyond the neutral position, its remote end which is connected to the rod 56 elevates the latter to open the cracking and pressure relief valves 48 and 38, respectively, to permit the return of actuating liquid from the working cylinder to the container. At the same time, the ball valve 68 is closed and the associated poppet valve 81 and the valve I83 are opened while the ball valve I8 is opened after the associated poppet valve 81 is first closed. Thus the supply of compressed air to the container and to the booster pump is out off while the booster pump is vented to the atmosphere so that the spring 25 may return the cooperating pistons 22 and 23 to retracted positions. At the same time the poppet valve 81 associated with the ball valve 10 being closed, compressed air is admitted into the working cylinder iii under the piston I i through the pipe 80 to assist the spring i3 in returning the piston H to its retracted position. When this has been effected, the lever 52 may be released and permitted to return to its neutral position.

It will be apparent from the foregoing that in the operation of the press the lever 52 may be operated first to admit air to the container l5 and thereby force actuating liquid from the latter into and through the barrel of the pump and into the working cylinder Ill to advance the ram i2 toward and into engagement with the work. When the pressure in the container [5 builds up to a predetermined value, the relay 52, which is responsive to the pressure in the container, is operative automatically to admit compressed air into the upper end of the chamber H in order to operate the motor piston 22 and the pump piston 23, thereby to force the actuating liquid under added pressure into the working cylinder and thus complete the operation of the ram. Upon movement of the lever 52 in the opposite direction, upon completion of the pressing operation, the pressure in the working cylinder is relieved and the pressure behind the motor piston 22 is relieved, while the poppet valve d! which is associated with the ball valve 58 is opened to relieve the pressure in the container It. When the lever 52 is permitted to return to its neutral position, the poppet valve 8 which is associated with the ball valve 10 opens and will remain open until the handle of the lever is again depressed to repeat anew the cycle of operations described, the poppet valve in its open position providing a vent through which air in the working cylinder l may escape both during the working stroke of the ram l2 and after completion of its return stroke. Any actuating fluid which escapes around the piston 23 may accumulate in the collar I-9 and drain back into the container through an opening act, the latter being closed by a pressure responsive valve I01 during use of the press but being permitted to open in the absence of a working pressure in the container 15.

The initial admission of compressed air directly into the container l insures filling of the barrel 2| of the pump, and the introduction into the Working cylinder ill of adequate actuating liquid to advance the working member toward and into engagement with the work and a preliminary action of the ram upon the work without the use of the pneumatically operated pump for the actuating liquid. Thereafter, the latter is automatically operative to complete the working stroke of the ram. The press, therefore, has the advantage that the time required to advance the ram through its working stroke and restore it to its original position preparatory to a succeeding stroke is reduced to a minimum, the use of compressed air to aid the spring [3 to return the ram to its original position upon completion of the working stroke having the further advantage that the press is thereby adapted to dieforming and other operations requiring the application of substantial forces to the ram to withdraw the latter upon the completion of such operations.

I claim as my invention:

1. A hydraulic press including a movable member, a cylinder containing a piston for actuating said member, a container for a body of actuating liquid, a pump for the actuating liquid, an element actuated pneumatically for causing the operation of said pump, a valve for admitting compressed air into said container to force actuating liquid into said cylinder to initiate the operation of said movable member, a relay valve which is responsive to the pressure in said container and which is automatically operative when said pressure reaches a predetermined value to admit compressed air to said actuating element, thereby to operate the pump to force actuating liquid under added pressure into said cylinder to continue the operation of said movable member, a Valve for relieving the pressure of said actuating fluid, a valve for relieving the pressure of said actuating element, a valve for admitting compressed air into said cylinder to restore said movable member to its original position, a pivotally mounted lever which may be rocked in one direction to open said first mentioned valve and which may be rocked in the opposite direction to open said last three-mentioned valves, and means for normally holding said lever in a position corresponding to the closed positions of said first, third and fifth mentioned valves and the open position of said fourth mentioned valve.

2. The combination with a hydraulic press which includes a movable member, a cylinder containing a piston for actuating said member, a container for a body of actuating liquid, a pump for the actuating liquid, an air pressure responsive piston connected to the movable element of the pump and a cylinder which provides a working chamber for the piston, air under pressure being admitted to and vented from said working chamber, and a relay valve which is responsive to air pressure in said container and automatically operative when such air pressure reaches a pre-determined value to provide for the operation of said pressure responsive piston, thereby to cause the operation of said pump, of a control mechanism which includes three Valve means, a single controlling element for said valve means, said element being normally automatically held in a neutral position from which it is movable in either direction to first and second operative positions respectively; and a compressed air supply line; the first of said valve means controlling the fiow of compressed air from said supply line to said container and said relay valve and the venting of compressed air from said container and relay valve, and in the neutral and second operative positions of said element having an operative phase in which the supply of compressed air to said container and relay valve is cut oil and the container and relay valve are in venting communication with the atmosphere and in the first operative position of said element having a second operative phase in which compressed air is admitted to said container and relay valve and the container and relay valve are occluded from venting communication with the atmosphere; the second of said valve means controlling the flow of compressed air from said supply line through said relay valve to the cylinder of the pressure responsive piston and in the second operative position of said element having an operative phase in which the cylinder of the pressure responsive piston is in venting communication with the atmosphere and in the first operative position of said element having a second operative phase in Which the cylinder of the pressure responsive piston is occluded from venting communication with the atmosphere and receives compressed air from the supply line through the relay valve; and the third of said valve means controlling the flow of compressed air to the cylinder for the piston which actuates the 'inovable member in order to effect the return of said piston to normal position, said third valve means having in the first operative position of said element an operative phase in which the cylinder for the piston which actuates the movable member is in venting communication with the atmosphere and having in the second operative position of the said element a second operative phase in which the cylinder for the piston which ac'tuates' the movable member is occluded from venting communication with the atmosphere and receives compressed air from the supply line.

3. A hydraulic press combination as set forth in claim 2 wherein the flow line for the actuating liquid is in communication with the container through a normally closed valve and the controlling element is so connected to said normally closed valve as to effect its opening when the controlling element is moved to its second operative position, thereby to provide for the return of the actuating liquid from the cylinder for the piston which actuates the movable member to the container, the valve being closed in the first operative position of said element.

4. A hydraulic press combination as set forth in claim 2 wherein the controlling mechanism is incorporated with the head of the cylinder for the pneumatic pump, the flow line for the actuating liquid is in communication with the container through a normally closed valve, and the controlling element is so connected to said normally closed valve as to eifect its opening when the controlling element is moved to its second operative position, thereby to provide for the return of the actuating fluid from the cylinder for the piston which actuates the movable member to the container, the valve being closed in the first operative position of said element.

FRANK C. WILSON.

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

UNITED STATES PATENTS Number Name Date 552,274 Cole Dec. 31, 1895 733,497 Martin July 14, 1903 1,486,304 Ross Mar. 11, 1924 1,903,887 Widener Apr. 18, 1933 1,927,085 Dinzl Sept. 19, 1933 2,050,191 Liebowitz Aug. 4, 1936 2,374,737 Desoutter May 1, 1945

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