US2443311A - Press with auxiliary ejector circuit - Google Patents

Description

June 15, 1948. w. ERNST ET A1,. 2,443,311

PRESS WITH AUXILIARY EJECTOR CIRCUIT Original Filed Aug. 28, 1959 3 Sheets-Sheet 1 ATTORNEYS June 15, 1948.

Original Filed Aug.

W. ERNST ET Al..

PRESS WITH AUXILIARY EJECTOR CIRCUIT 3 Sheets-Sheet 2 @Xd-mu /I TTORNEYJ W. ERNST ET AL PRESS WITH AUXILIARY EJECTOR CIRCUIT June l5, 1948.,

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ATTORNEYS.

Patented June 15, 1948 UNITED STATIIS PATENT CFFICE PRESS WITH AUXILIARY EJECTOR CIRCUIT Walter Ernst, Mount Gilead, Johan A. Muller, Dayton, and Victor S. Shaw, Mount Gilead, Ohio, assignors to H-P-M Development Corporation, a corporation oi' Delaware 2 Claims.

The invention relates to hydraulic piess circuits and, in particular, to such circuits having means therein for electing workpieces.

This application is a substitute for abandoned application, Ser. No. 292,270 iiled August 28, 1939, which was a division of application Ser. No. 225,155 tiled August 16, 1938 (Pat. No. 2,229,965, granted Jan. 28, 1941).

One object of this invention is to provide a hydraulic press circuit having a Vdouble-acting main plunger, together with means for utilizing the fluid displaced from one side of this doubleacting plunger to operate an auxiliary plunger, without the necessity of employing an additional l11111111.

Another object is to provide such an auxiliary plunger operating circuit, wherein the auxiliary plunger is caused to move to apredetermined position and then to automatically halt as the fluid supplied thereto reaches a discharge port uncovered by the auxiliary plunger in its motion.

Another object is to provide an auxiliary plunger operating circuit, as described above, wherein the pump for operating the main plunger performs no work while the main plunger is in its retracted position other than circulating the oil, except when the auxiliary plunger is being moved either in a forward or a reverse direction.

In the drawings:

Figure 1 is a diagrammatic view, mainly in section, showing a complete hydraulic press operating .circuit including this invention.

Figure 2 is a diagrammatic view, mainly in section, showing that part of the circuit of Figure 1 employed for operating an auxiliary plunger, such as an ejector plunger, without an additional pump.

Figure 3 is a central vertical section through a commercially constructed embodiment of the auxiliary plunger or ejector plunger, shown in Figures 1 and 2.

Figure 4 is a view of the lower central portion of Figure 3, but showing the ejector plunger in its lowered or retracted position.

General arrangement In general, the invention consists of an auxiliary plunger, such as an ejector plunger, which is operated by the fluid supplied from one side of the main plunger, while the other side is connected to exhaust. The auxiliary plunger, in itself, is constructed to serve as a sleeve valve for regulating its own action by uncovering discharge ports at predetermined points in its forward and return strokes. -In this manner the 'auxiliary plunger is actuated without the neces- (Cl. SIP-97) sity for an additional pump, and moves to a predetermined position and halts so that the pump discharge is merely a free iiow, without consuming any great amount of work except at those times when the auxiliary plunger is actually being moved.

This invention is found to be of great value in certain applications of fluid pressure, where it is desirable to vary the intensity of the applied pressure in a predetermined manner. In the molding of certain compounds, for example, it has been found desirable to apply a moderate pressure for a time While the molding material softens and partially conforms to the shape of the mold, and thereafter to apply a higher pressure to force the softened material into the more intricate recesses of the mold so as to ll these recesses fully.

Press construction Referring, to the drawings in detail, Figure 1 shows diagrammatically in vertical section a hydraulic press having a bed I0 and head II, inter-connected by side members or uprights I2 at interlocking dove-tail portions I3 and I4, respectively. Mounted upon the press head II is a surge tank I5 for containing and supplying the operating fluid utilized in the circuit. The press head II contains .a mainv cylinder bore I6, one end of which serves as a press-advancing chamber I'I, and the other end I8 has a press retracting chamber, these being on opposite sides of the piston head I9 of the main plunger 20. Thus, the main plunger 20 is a double-acting plunger, reciprocating in the cylinder bore I6.

Opening into the press-advancing chamber I'I is a port 2|, providing communication with the interior of the surge tank I5. Mounted in the port 2| is a double-acting surge valve 22, of the type disclosed in the patent to Walter Ernst, No. 1,892,568, of Dec. 27, 1932. The details of this surge valve 22 form no part of the present invention, and its function is as a check valve, which opens when the main plunger 20 starts on its downward stroke under the influence of gravl retracted positions (Figure 2).

I5 without traversing the remainder of the hy draulic circuit.v Attached to the main plunger is a platen 25 which moves up and down between the press side members I2 and is guided thereby. The platen is provided with two cam portions 26 and 21, for operating certain valves at predetermined positions upon the stroke ol the platen 25. Surrounding the main plunger 20, for the prevention of leakage therefrom, is a packing 28 compressed by a gland 29. f

Ejector sub-ciwuit I'he ejector circuit shown at the bottom and right-hand side of Figure lis shown in simpliiied form in Figure 2. In this circuit the main cylinder bore l5 is provided with an intermediate portv 2| I, from which a line 2|2 runs downwardly to a normally open two-way valve 2|3. The latter is provided with a valve rod 2I4 adapted to be engaged and shifted to close the valve 2 |3 when the cam 21, upon the yplaten 25 of the main plunger 20. comes into contact with it. From the twoway valve 2| 3, the line 2|5 runs downwardly to the manually operated four-way valve 2I6 having a valve rod 2|1. From the four-'way valve 2I9 the discharge line 2|8 runs back to the 'surge tank I5.v Additional lines 2|e9' and 220 run, respectively, to top and bottom ports 22| and 222 of the ejector cylinder 223. The latter is likewise provided with an intermediate port 224, to which is connected the line 225 leading through the upwardly opening check valve 226 to the line |4|. 'I'he latter runs from the main valve control valve |45* to the upper end of the main cylinderbore I6. The ejector cylinder is provided with a piston head 221 having thereabove an ejector plunger 228.

reaches its retracted position.

In the operation of the ejector circuit shown in Figure 2, let it be assumed that the main plunger 20 and the ejector plunger 229 are in their To operate the ejector plunger 22B, the main control valve |40", which lcontrols the main plunger 20, is assumed to be in such a position as to cause retraction oi the main plunger 20. That is. so that pressure fluid ows from the pump 35, through the line |31, the valve |4|ll and the line 24, into the space beneath the main piston head I9. The space above the latter is open to exhaust into the surge tank I5 by way of the line- I 4|, the main control valve I4II'l and the line |42. Since the platen cam 21 is retracted, the two-way valve 2I9 is in its normally open position so that the flow or pressure uid into the space beneath the main piston head I9 passes out through the port 2|| and the conduit 2I2, through the now open valve 2|3, into the conduit 2I5.

Let it be 'assumed that the four-way valve 2|6 is positioned so that the pressure fluid from the line 2I5 ows through the valve 2|6, into the line 2|9, and through the upper port 22| of the ejector cylinder 223 into the space above the ejector piston head 221. By the same positioning of the four-way valve 2I5, the space below the piston head 221 is open to exhaust into the surge tank I5, through the port 222, the line 220, the fourway valve 2|.6 and the line 2|8. It the ejector plunger 228 is in its lowered position (Figure 2) so that the piston head 221 thereof is down, then the ow of uid through the line 2|9 and port 22| is by-passed and discharged through the middle port 224, the line 225, the check valve 226, the line I4I, the main control valve |4|ln and the line |42, into the surge tank I5. Thus, a by-pass of the pump discharge 30 occurs when the main To operate the ejector mechanism, the operator shifts .the valve rod 2| 1 so that the ow of pressure iiuid from the line 2|5 passes through the four-way valve 2I5, into the line 225 and through the port 222, into the lower end of the ejector cylinder 223. Under this influence the ejector piston head 221 rises until it reaches the dotted position shown in Figure 2, and uncovers g the middle port 224. The tluid entering the lower port 222 is thereupon by-passed through the port 224, the line 225, the check valve 229, the line I4I, the main control valve |4|IIl and the line |42, into the surge tank I5. Therefore, after the ejector plunger has accomplished its electing action, the dow of the pump 39 again is by-passed through the middle port 224. The vertical width of the ejector piston head 221 and the separation of the ports 222, 224 and 22| are proportioned so that this result occurs. In this manner the ejector piston head 221 serves not only as a piston head but also as a valve head for uncovering the port 224 after its work has been finished, either upon the ejection stroke or upon the retraction stroke. When the main piston head I9 is in its retracted position (Figure 2), therefore. the pump 30 is performing no work except to circulate the working lluid through the circuit previously described, into the surge tank I5. This circulation occurs except when the ejector plunger 228 is being moved either upwardly or downwardly.

The presence ofthe platen-operated two-way valve 2|3 is not essential to the successful operation of this circuit. It is optionally inserted in the circuit so as to protect the ejector cylinder 223 against high pressure iluid. It will be observed that if the travel of the main piston head I9 is suillcient to uncover the port 2| I leading into the line :I2 when the main plunger advances sufliciently far upon its working stroke.

then high pressure uid will not be detrimental f since without the valve 2|3 it will merely ilow through the line 2I5, the four-way valve 2I5,' the 223 to withstand this high pressure. In order to prevent the flow of high pressure fluid through the ejector cylinder 223 at the end of the working stroke of the main plunger 225, the cam 21 at this p olnt engages and shifts the valveA rod 2 I4 of the normally open valve 2|3 into its closed position. Thus, when the platen 25 is moved downwardly to the proper point, the-pressure will be shut on vfrom the four-way valve 2| 5 and the ejector cylinder 223 by means of the closing of the normally open valve 2|3. The provision of the upwardly opening check valve 226 in the line 225 prevents the backing up of pressure iluid in the line 225 from the line |4| during the pressing stroke. Moreover, the automatic closing of the two-way valve 2 I 3 when the platen 25 is down, eiectively prevents the ejector plunger 224 from being operated by error. 'Ihis prevents possible damage to the apparatus by the accidental operation of the four-way valve 2I5.

'I'he ejector cylinder 223 shown in Figure 2 is a simplified form. Figure 3 shows a commercial form of the same device. The construction shown in Figure 3 was so designed that all pressure connections and piping are concealed as much as possible within the press, and also to utilize a limited space because the height of the pressing table was limited. 'I'he ejector shown in Figure 3 also has the 'feature of serving as a valve member for by-passing the ilow of the pump when the ejector plunger is in its raised or lowered positions.

Mounted upon the press bed Ill is a bolster plate 238, in which is provided a socket 23|. Secured within the socket 23|, as by the screws 232, is a tube 233 having a iianged portion 234 for receiving the lower ends of the screws 232. 'I'he latter pass downwardly through holes 235 in the bolster plate l23|). The bolster plate 230 is provided with a horizontal bore 236, communieating with a transverse bore 231 and longitudinal bore 238 in the tube 233. The latter extends downwardly into a corresponding bore 239 within the ejector plunger 24|), the latter having an enlarged piston head 24| operating in an enlarged bore 242. Secured to the upper end of theejector plunger 24W, as by the screws 243 (one only being shown), is the ejector platen 244. A gland 245 and packing 246 serve to prevent leakage from the internal bore 239 past the upper portion of the tube 233. The ejector plunger 240 is provided with'a transverse passageway 241 a short distance above the upper edge of the piston head 24|. A

packing 248, compressed by the gland 249, similarly prevents leakage around the outside of the ejector plunger 240.

The outer end of the horizontal Ibore 236 is closed by a threaded plug 250, and an intermediate port 25| is connected to the pipe 2|9, previously described. The lower end of the cylinder bore 242 is provided with a port 252, similar to the port 222' in Figure 2 and connected by the passageway 253 leading to a connection with the pipe 220, previously described. One portion of the port 252 is closed by the threaded plug 254. The ejector cylinder bore 242 is provided with middle and upper ` ports 255 and 256, communieating respectively with the parallel bores 251 and 258. The bore 251 is closed at its outer end by the threaded plug 259, whereas the bore 258 is connected to the conduit 225, previously described. The bores 251 and 258 are inter-connected by the bore 26|, closed at its upper end by the threaded plug 262.

The operation of the ejector mechanism of Figure 3 is similar to that of Figure 2, previously described. Let it be assumed that the ejector platen 244 is in its raised position, as shown in Figures 1 and 3, so that the ejector has performed its ejecting action. To retract the ejector platen 244 the operator shifts the -four-way valve 2|6 so that pressure uid passes into the line 219, in the manner previously described (Figure 2). The pressure iluid from the line 2|9 passes through the port 25| and the passageways 236, 231 and 238, downwardly through the tube 233 into the lower end of the plunger bore 239. This forces the ejector plunger 24|) and its piston head 24| downwardly until they occupy the position shown in Figure 4. When this occurs the transverse plunger passageway 241 passes the lower end of the tube 233 and opens up the plunger bore 239 for communication with the .upper horizontal passageway 258. The discharge of the pump 30 thenceforth is by-passed from the plunger bore 239, through the passageway 241 and the upper bore 258, which connects 4with the pipe 225 (Figure 2) leading through the check'valve 226 to the pipe |4|, thence through the main control valve |40* to the discharge line |42 and the surge tank |5.

When it is desired to operate the ejector plunger 24|) in the opposite direction so as to raise the ejector platen 244 from the position shown in Figure 4 to that shown in Figure 3, the operator shifts the four-way valve 2|6 (Figure 2) so that pressure iluid is admitted through the line 220 and port 252 to the space beneath the ejector piston head 24| (Figure 4). The pressure beneath the piston head 24| raises the plunger 240 until the piston head 24| uncovers the port 255, whereupon the discharge of pressure fluid is subsequently by-passed through the bores 251, 26| and 256 into the conduit 225, as previously described. The ejector plunger advancing area is thus the lower end 263 of the piston head 24|, whereas the return area thereof consists of the lower end 264 of the plunger bore 239. The passageway 265 within the ejectorplunger 2491s solely for the purpose of taking care of leakage and also to prevent pressure from building up under the packing 246.

The remaining portions of the circuit shown in Figure 1 are described and claimed in our Patents No. 2,229,965 (issued Jan. 28, 1941) and No. 2,239,147 (issued April 22, 1941).

It will be understood that we desire to comprehend within our invention such modifications as come within the scope of the claims.

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

1. In a hydraulic press system, a main hydraulic motor having advancing and retracting areas, a pump, a circuit connecting said main motor with said pump, an auxiliary hydraulic motor having an auxiliary cylinder and an auxiliary piston, connecting means for hydraulically connecting said auxiliary motor with said main motor, means associated with said auxiliary motor for by-passing the flow of pressure uid thereto in response to the motion of said auxiliary piston to a predetermined position, a valve in said hydraulic connecting means for regulating the supply of pressure fluid to said auxiliary motor to control the actuation of the latter, and controlling means in said circuit for controlling the operation of said main hydraulic motor independently of the actuation of said auxiliary motor and the position of said valve.

2. `In a hydraulic press system, a main cylinder having a ram advancing portion and a ram retracting portion, a double acting main ram therein, means for supplying pressure fluid to said main cylinder, an auxiliary cylinder, an auxiliary piston therein, a hydraulic connection between said auxiliary cylinder and said main cylinder, controlling means in said hydraulic connection adapted to allow operation of said auxiliary piston in either direction while said ram is held stationary, means for controlling movement of said ram independently of said auxiliary piston and said controlling means, and lmeans responsive to the travel of said auxiliary piston to a predetermined position for exhausting uid from said auxiliary cylinder,

WALTER ERNST. JOHAN A. MULLER. VICTOR S. SHAW.

`(References on following page) 7 REFERENCES CITED Number The following references are of record in thy fue of this patent: l 2,331,109

y UNITED STATES PATENTS 5 Number v Name Date 2,112,466 Maman Mar. 29, 193s NTsllgo- 2,197,428 Erb Apr. 16, 1940 Name Ditev Ernst et al. Jan. 28, 1941 Austin May 1B. 1943 De Ganahl Oct. '5, 1943 FoRmGNfPATENTs Country Date Germany Oct. 20. 192?

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