US2343177A - Hydraulic press - Google Patents

Description

P. E. FLOWERS HYDRAULIC PRESS Filed June 25, 1941 '2 Sheets-Sheet 1 lNvcm-r'cw PAUL. E. Rowen BXZZJJ 4M4 AT ToRb E71 '80 fljijzj I Feb. 29, 1944. v P. E. FLOWERS 2,343,177

HYDRAULIC PRESS Filed June 25, 1941 2 Sheets-Sheet 2 47 4a. 46

l "1 :15 ---'L V I INVE 'm? v PAUL .FLOWEp AT Ton NE.

Patented Feb. 29, 1944 HYDRAULIC muss Paul E. Flowers, Mount Gilead, Ohio. assignor to The Hydraulic Development Corporation,

Inc.,

Wilmington, Del.-, a corporation of Delaware Application June 25, 1941, Serial No. 399,681

'1 Claims. (cl. 60-97) This invention relates to hydraulic presses and, in particular, to hydraulic presses in which,

during the first portion of the pressing stroke,

fluid is surged into the press cylinder through a surge valve.

Such presses are built with a ram having a one-pressure ram surface, and also with a compound ram, one portion of which is adapted to impart a relatively low pressing effect upon the press platen, while another portion, in cooperation with said first mentioned portion, may impart a relatively high pressing effect upon the platen. Heretofore, different cylinder castings were required, depending on whether the press was to be provided with a one-pressure ram or a compound ram. In the latter instance, a plurality of surge valves was needed, which surge valves were heretofore arranged sideflby. side at the top of the press cylinder and, therefore, required an enlarged top portion of'the press cyl inder. On the other hand, when the press was provided with a one-pressure ram, the employment of such press cylinder with an enlarged top portion was not only unnecessary, but actually constituted a waste of material and casting costs,

and even incurred additional costs and labor for plugging the superfluous surge valve hole or holes. Accordingly, it is an object of the present invention to provide a press structure which will overcome the above mentioned drawbacks, while simplifying the casting for the press cylinder.

It is another object of the invention to provide a press structure in which one and the same press cylinder with only one surge valveopening may be used for a one-pressure ram press as well asfor a compound ram press.

A further object of the invention consists in These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanyi g drawings, inwhich:

g e 1 is a diagrammatic illustration of a press structure according to the invention.

. Figure 2 shows, on a somewhat enlarged scale, the upper portion of the press cylinder of Figure 1.

Figure 3 is a section along the line 3-3 of Figure 2.

. General arrangement to admit pressure fluid to the outer annular ram surface as well as the inner ram surface for exerting an increased pressure on the ram. In each instance fluid from a surge tank is admitted through both surge valves during the first portion-of the pressing stroke prior to the engagement of the work piece by the platen.

The press structure according to the invention allows the employment of one and the same press cylinder and, if desired, even with one andthe same surge valve, irrespective of whether the press is provided with a one-pressure ram or a compound ram.

the provision of a press having a compound Ira m "'with an outer and an innerv ram area, in w ch the surge valve admitting fluid to the inner ram I area is arranged inside the press cylinder housing the ram.

Still another object consists .in the provision of a press having a ram with an outer and an inner ramarea, in which one surge valve'is mounted at the top of the main cylinder housing the top of a tubular member inside the press cylinder. v

It is' a still further object of the invention to provide a compound ram presswith an outer and an inner ram area, in which the surgevalves for-admitting fluid to' the outer and inner ram areas are so arranged that one is located beneath the other,

, ram, while another surge valve is arranged :on

In the last mentioned instance, the structure of Figure 1 may be used, whereas in the first instance, the compound ramand .the tubular memher-inside the press cylinder is replaced by a one-pressure ram, while no changes in the structure of the presscylinder itself are required. Structural arraagem ent Referring to the drawings in detail, the press shown in Figure 1 comprises a press head i and a press bed 2 spaced from each-other by side members I and interconnected by strain rods not shown in the drawings.

The press head I comprises a press cylinder 4 having re'ciprocably mounted therein a compound press ram 5 with an outer annular press area i and a bore 1, the bottom of which constitutes an inner press area 8. Stationarily mounted within the press cylinder 4 and extending into the ram bore 1 is a tubular member having a tubularextension connected to the press cylinder 4 in any convenient manner, for instance by screws The tubular extension is provided with radial slots l2. s

Connected to the ram 5, in any convenient manner, is a platen l3 adapted to exert pressure on a work piece on the press bed 2. To prevent oleakage between the press cylinder 4 and the ram 5, packing material I4 is provided compressed by a gland l5, which is connected to. the lower portion of the press cylinder 4. The press ram 5 is a double-acting ram, the lower portion of which confines, with the wall of the cylinder 4, an annular space It communicating through conduit H with one side of a reversible variable delivery pump l4, the other side of which-communicates through conduit I! with the bore of the tubular member I.

Branching of! from the conduit I9 is a conduit 2| leading to the upper end of a surge valve 22 mounted on and connected to the top portion of the tubular member 5. A similar surge valve 23, but of greater capacity, is connected to the upper portion of .the press cylinder 4'. Since both surge valves 22 and 23 are of the same construction, only the structure of the surge valve 23 will be described.

The surge valve 23 (Figure 2) consists of a tubular casing 24 mounted in the bore 25 of the press head I and containing an end cap 25. The

' tubular casing 2 4 is provided with outlet ports 21 leading from the interior of the casing 24 into the chamber 28 on top oiKthe' press cylinder 4, which chamber communicates with the interior of the tubular extension ll. The cap 24 is pro-, vided with a hollow projection 29 and serves as a seat. for the coil spring 35-, the opposite end of which urges the surge valve member 3| upwardly. The surge valve member 4| is provided with pump by-pass valve 52 having pipe connections 53 and 54. The main cylinder release and pump by-pass valve 52 serves for relieving the pressure on top of the ram at the initiation of its retraction stroke, and for a more detailed description thereof, reference may be had to U. 8. Patent -No. 2,268,205 to Walter Ernst.

The pipe 53 leads to a tonnage control valve 55 which, in response to a predetermined pressure acting upon the advancing side of the press ram 5, establishes hydraulic connection between the pipe 53 and the conduit 55 leading to the surge tank 40. The tonnage control valve 55 may be of any desired type, preferably of the type disclosed in U. S. Patent No. 2,224,957 to Walter Ernst.

Communicating with the pipe 52 is a conduit 51 leading to the conduit H. A conduit 54 communicates through the slots l2 with the upper portion of the press cylinder 4, and also leads -to a distributingvalve 59 which has connected thereto a conduit 60 communicating with the conduit IS. The distributing valve 59 is a two-way valve with a valve member 5| connected to the valve rod and adapted to be controlled thereby so that when the valve rod 53 is shifted to its lower position, hydraulic communication is established between conduits 50 and 58, whereas normally a spring 52 connected to the valve member 6| holds the latter in uppermost position, thereby preventing hydraulic communication between the conduits 60 and 58.

The lower end of the valve rod 53 is provided with a threaded portion 54 to support a nut 55 upon which rests a coil spring 55 surrounded by a tubular cap 51 having a bore 58 therethrough through which passes the valve rod 53. The cap 51 is adapted to be engaged by the platen arm a beveled portion 32 adapted to engage a valve seat 35in the casing 24 so as to interrupt hydrauliccommunication between the bore 34 in the casing 24 and the ports 21.

Mounted above the tubular casing 24 is a cylindrical casing having a flanged portion 35 rest- 58 connected to the platen l3 for shifting the valve rod 53 downwardly.

The platen arm 59 is also adapted, when the ram approaches the end of its return stroke, to engage a collar 10 adiustably mounted on a control rod H, the upper portion of which has adjustably connected thereto a collar 12 for engagement with a two-arm lever I3 shiitable about the pivot 14. One end of the lever 12 is pivotally connected with an armature I5 controlled by a solenoid 16 which, when energized, puts the pump l8 in full delivery forward stroke position. The

' solenoid I5 is electrically connected with the bore a registering with the bore 34 into the fluid reservoir or surge tank 44. The-cylindrical casing 35 is provided with-a stepped bore 4|, the upper portion of which houses 'a spring 42, while the lower portion houses a guiding sleeve 42. Passiiigthrough the bore in the guiding sleeve 43' is an operating rod'44 provided with a head 45 which is continuously urged by the spring 42 against the closure member 45 connected to the casing 25. Passing through the closure member 44 is a bore 41 connected to' a conduit 48 which communicates with the conduit i1.

Fluid pressure admitted through the conduit 48 is adapted to act upon the head 45 so as topress the operating'rod 44 downwardly a ainst the thrust of the spring 42, thereby moving the surge valve member 3 downwardly away from the valve seat a and against the thrust oi the spring Ill.

' Connected to the conduit 44 is a conduit 49 comprising acheck valve 5. adapted to admit fluid from the surge tank 44 into the conduit 48, while preventing the flow in the other direction. Also branching oil from the conduit 48 is a contonnage control valve 55 so that it is tie-energized when the tonnage control valve is actuated.

The lever 14 is also connected by a link system 11 with the flow-control member 14 of the pump !8. .The movement of said flow-control member in one or the other direction is adapted to shift the pump |8 from neutral to full delivery forward stroke position or to full delivery retraction stroke position. The pump I! which does not form a part of the present invention may be 01' any desired type, for instance, the type disclosed in U. S. Patent No. 2,184,665 to Ernst.

The connection of the conduits so and I! with the cylinder 4 and the bore 2. respectively may be effected in any desired manner, for instance.

in the manner shown in Figure 2. As will be seen.

therefrom, the passageway 15 at the upper portion of the bore 20 pertaining to the tubular member 9 is provided with a shoulder 80 having packing material 4| therein which is compressed by a tubular extension 82 of a gland 83 which also compresses'packing material 84 inthe recess 85.

The gland 53 which is connected by screws 45- dun 5| m w a main cylinder release and to the cylinder 4 has a recess 81 with packing- Operation The press shown in the drawings may be operated in two difierent ways, depending on the nature of the work and the desire of the operator.

If it is desired to use only the inner ram area 8 of the press ram, such as for deep drawing work,

where a maximum ram speed is essential on ac- 1 count of the long stroke under pressure, the cap 81 is lowered by turning the nut 85 upon the valve rod 88 so that it will not be engaged by the platen arm 89 during the downward movement of the platen i3.

When the pump l8 is'started, and due to energization of the solenoid I6, the linkage it has shifted the pump to full delivery forward stroke position, pressure fluid delivered by the pump passes through conduit it into the bore of the tubular member 9, while fluid is withdrawn from the annular space It through conduit ii to the pump l8. As a result thereof, the ram 5 starts to move downwardly by gravity as fast as fluid is withdrawn from the annula space it. As soon as the downward movement of the ram 5 starts, a suction efiect is created within the bore 20 of the tubular member 8 and also in the upper portion of the cylinder d, which suction effect The opening of the surge valve 22 is effected similarly.

Fluid expelled by the upwardly moving ram 5 passes from the bore 20 of the tubular member 9 through the surge valve 22 into the upper portion of the press cylinder 4 and from there through surge valve 28 into the tank All.

When the press ram 5 approaches the end .of its retraction stroke, the platen arm 89 engages the collar I8 and lifts the control rod ll so that the latter, by means of the collar 12 and linkage l1, shifts the pump l8 to neutral or substantially no delivery position. The ram 5 then comes to a standstill and the press is ready for a; new cycle.

If now it is desired to use the outer annular ram area 6 as well as the inner ram area 8 to employ the maximum pressure of the press, the cap Bll is moved upwardly along the valve rod 53 by turning the nut 85 so that the platen arm 69, when moving downwardly, will engage the causes the surge valve member 3! to move down wardly against the thrust of the spring 38 (Figure 2) and, similarly, causes the opening of the surge valve 22. Therefore, while the ram 5 moves downwardly, fluid is withdrawn from the tank at through the passageways 88 of the surge valve 28 into the upper portion of the press cylinder ii, and a part of the fluid thus surged into the upper portion of the press cylinder 5 passes through the surge valve 22 into the bore 28 of the tubular member 9. In this way, the increasing spaces above the outer ram area 6 and the inner ram area 8 are maintained filled with fluid.

When the platen lsengage's the work piece and encounters resistance, pressure builds up within the bore 2b of the tubular member ti, thereby causing closure of the surge valve 22.

\ji'hepressure within the bore it continues to act against the inner ram area b for performing the actual pressing operation. When, at the end of the pressing operation, the pressure on the inner ram area 8 reaches a predetermined value, this pressure is conveyed through conduits to, at and 53 to the tonnage control valve es, causing the latter to break the energizing circuit forthe solenoid l8, whereupon a spring (not shown) in the servomotor pertaining to the pump i3 shifts the pump to full delivery retraction stroke position.

Fluid pressure is now delivered by the pump 18 through conduit l1 into the annular space it,

and also through conduits 2: and 4a to the surge valves 22 and 23 respectively. After the main cylinder release. and pump byduit 48 upon the head connected to the operating rod 44, thereby causing-the latter to engage and move downwardly the valve member 3| against the thrust of the springs 42 and -80.

cap Bl at a desired point. The pump i8 is then started and, in the manner previously described by energization of the solenoid i6, is shifted to full delivery forward stroke position. Pressure fluid is then passing from the pump it through the conduit i9 into the bore 20 of the tubular member a as before, while fluid is withdrawn from the annular space l6 through the conduit ill. The ram 5 then moves downwardly by gravity in the same manner as previously described.

When the platen l3 has moved downwardly to such an extent that the platen arm 89 engages the cap er, further downward movement of the platen it causes the platenarm 89 to shift the valve rod 63 downwardly, thereby establishing hydraulic connection between the conduit it and the conduit 58 so that pressure fluid from the pump it also passes through conduit 58 into the upper portion of the press cylinder l, thereby acting on the annular outer ram area 6. From now on, both ram areas, 5 and 8, are subjected to pressure fluid from the pump i8. It is, of course, understood that the surge valves 22 and 23 had closed prior to or concomitantly with'the downward movement of the valve member 63.

As soon as, at the end of the-pressing stroke, the pressure on the ram 5 has reached a predetermined value, this pressure is again conveyed to the tonnage control valve 55 through conduits i8, bl and 58, so as to cause the tonnage control valve to break the energizing circuitfor the solenoid it; The pump it is thenoreversed and causes the retraction stroke of the ram 5 in the manner described above.

As soon as the platen arm 69 has released the cap 87; the latter is restored to its previous position with regard to the valve rod 83 by means of the spring 66, while the spring 62 connected to the valve member SI in the distributing valve 58 returns the valve member 6| and the valve rod 68 to their upper positions. At the end of the retraction stroke, the platen arm 89 again en per portion and since only one hole for receiving one surge valve'is required, Moreover, the casting 4 may be used for a compound ramas shown in the drawings as well, as for a one-pressure area ram without requiring any changes in its structure.

The provision of the surge valve 22 pertai ing to the inner ram area 8 inside the press cyli der 4 results in a concentrated arrangement or the surge valves 22 and- 23, thereby simplifying the I press structure and giving the same a highly shown in the drawings, but may also be inclined to the longitudinal axis of the tubularmember 9, thereby enabling a reduction of the total length of the press cylinder 4. The specific construction of the surge valves 22 and 23 referred to above has been given merely as an example, and it is obvious that other surge valves may be used instead thereof.

It will be understood that I desire to compre-- top and bottom and having a partition separating the upper portion from the lower portion and also having a slot in the upper wall portion, a

.firstsurge valve arranged adjacent the upper to said inner and outer ram areas, and means for admitting fluid through said surge valves.

2. In combination, a cylinder, a ram having an outer ram area and a chamber with an inner ram area, a tubular member having an upper portion and a lower portion separated from each other .by a partition, screws passing through said cylinder and entering the upper portion of "said of said tubular member for eifecting hydraulic communication between the inside of said upper tubular portion and said outer ram area, a fluid storage tankmounte'd on said cylinder, 9. first surge valve mounted on said cylinder and hydraulically connectedto said storage tank, screw member, said second surge valve being operable to effect hydraulic communication between said upper portion of said tubular member and said inner ram area, a/fiuid pressure source, and

means for selectively supplying pressure fluid from said fluid source to said inner ram area alone, or to both said inner ram area and said outer ram area.

3. In combination, a cylinder, a ram reciprocable in said cylinder and having an outer ram area and a chamber with an inner ram area, a tubular member stationarily mounted with respect to said cylinder and extending into said chamber, said tubular member and said chamber being adapted in cooperation with each other to act as a cylinder-piston-assembly, fluid storage means, first valve means adapted in response to a suction effect in said cylinder to allow fluid to pass therethrough from said storage means into said cylinder, second valve means associated with said tubular member and arranged inside said cylinder, said second valve means being adapted in response to a suction effect in said chamber to admit fluid irom said cylinder to said inner ram area, pressure fluid means. and control means associated with said pressure fluid means and operable for admitting pressure fluid from said fluid pressure means selectively to said inner ram area only or jointly to said inner ram area and said outer ram area for respectively actuating said ram. at a high or at a lower pressure.

4. In combination, a cylinder, a ram reciprocable in said cylinder and provided with an outer ram area and an inner ram area, a first fluid source, a first surge valve associated with said cylinder and operable to establish hydraulic communication between said first fluid source and said outer ram area, a cylindrical member sta- I ,tionarily mounted within said cylinder for cooperation with said inner ram area, a second surge valve mounted in spaced relationship to and below said first surge valve, said second surge valve being adapted in response to a'suction eiiect in said cylindrical member to admit fluid from said cylinder to said inner ram area, and a second fluid source for admitting pressure fluid selectively to said inner area only or jointly to said inner area and said outer area.

. 5. In combination, a cylinder, a ram reciprocable in said cylinder and provided with a first area and a second area separated from each other, 5 uid storage means, a first surge valve mounted on and extending through said cylinder for admitting fluid from said storage means to said first area in response to a suction effect in said cylinder, a second surge valve spaced from said first surge valve and arranged completely within said cylinder, said second surge valve being adapted in response to a suction eiIect exerted 1 thereupon to admitfiuid passing from said storage means through said first surge valve, to said second area, a pressure fluid source, and means operable for admitting pressure fluid from said fluid source selectively to said second area only or jointly to said first and second areas.

6. 1In combination, a cyllnderp'a plunger reciprocable in said cylinder and provided with a first efi'ective area, cooperating withafirst working chamber in said cylinder, and also provided with a second eiiective area, cooperating with a second working chamber in said cylinder, a first fluid source adapted to supply fluid to said first and second workingchambers to prefill the same, first valve means operable ,to establish fluid connection between said first fluid source and said first chamber, second valve means operable to establish fluid connection between said first and said second chambers, and a second fluid source independent of said first fluid source for selectively supplying pressure fluid to said second chamber only, or to both said first and said second'chambers, for actuating said plunger.

7. In combination, a cylinder, a tubular member stationarily mounted in said cylinder, a plunger reciprocable in said cylinder and provided with a first area forming with said cylinder 2. first chamber, and also provided with a second area forming with said tubular member a second chamber, a first fluid source, first valve means operable to establish fluid connection between said first fluid source and said first chamher to allow flow of fluid from said first fluid source intosald flrstchamber to preflll the same,

' or vice versa to allow escape of fluid from said first chamber, second valve means operable to establish fluid connection between said first and second chambers to allow, in cooperation with said first valve 'means, prefllling of said second chamber with fluid from said fluid source or to permit escape. of fluid from said second chamber to said fluid source, a second fluid source, and

PAUL E. FLOWERS.

Images