US2364566A - Extruding press - Google Patents

Description

Dec. 5, 1944- s. H. sTUPAKoFF ErAL 2,364,566

' EXTRUDING' PRESS Filed Sept. 5, 1942 named Dec. s, 1944 Ex'rmmmc PRESS Semon H. Stupakoi'f, Latrobe, and Rawson E` Stark, Greensburg, Pa., assignors to VStupakofl Ceramic & Manufacturing Company, Latrobe,

Pa., a corporation of Pennsylvania Application' september 5, 1942, seria1N6.45'z,416

(ci. :a-16) 1o claims.

is charged into the open end of a cylinder, the.

axis of which is vertical. At the bottom of the cylinder is a die. A ram forces a piston down into the top of this cylinder compressing the mix within the cylinder and forcing it out through the opening inthe die at the bottom of the cylinder. As the material emerges from the die it hangs in suspension. After it has' reached a predetermined length and usually before it contacts the base of the press, it is removed and a new length of material is likewise extruded. It is important that the material be compacted under considerable pressure in order that it will have the desired density. It is also important that it be free of air bubbles and that it be straight as it hangs from the die.

Heretofore a considerable amount of extruded material was defective due to the inclusion of air and air bubbles in the mix. Frequently a bubble of air under several thousand pounds of pressure per square inch would, when the material emerged from the die, expand with a loud report and rupture the material being extruded. Lesser amounts of air will produce small fissures, voids and irregularities in the material. Various attempts have been made to eliminate this difficulty but, so far as we know, such attempts have been unsuccessful.

According to .the present invention, the loose material is charged into the extrusion chamber or cylinder in batches, and after each batch the air is evacuated and the material iscompacted while it remains under vacuum. Thereafter the.cornpacted material is placed under vacuum and most of the residual air is Withdrawn and then, before the seal to the air is broken, the extruding operation is commenced and air is prevented from getting back into the cylinder during such extrusion. The invention is preferably embodied in a press of more or less conventional type having two cylinders which may alternately be brought to position under the extrusion ram. During the time that one cylinder is in position for the material to be extruded therefrom, the other cylinder is in a position where the batch of material may be charged into it. According to our invention, vacuum cups are arranged to be positioned over the .ends of both cylinders so that the contents of each cylinder may be evacuated to a predetermined extent, as will hereinafter more fully appear.

Our invention may be Vreadily understood by reference to the accompanying drawing in which Figure 1 is a side elevation of a press embodying our invention, certain parts thereof being shown in section;

Figure 2 is a transverse horizontal section in substantially the plane of line II-II of Figure 1.

In the drawing 2 and 3 are parallel columns supported on pedestals 4 carried on a base member 4a. At the top of these columns is supported a hydraulic cylinder 5 having a piston 6 with a plunger 'l on the lower end thereof.

Mounted on the column 2 is a sleeve 8 which has two similar arms 9 and III. Each arm carries a cylinder, these cylinders being designated II and I2. The two cylinders are preferably of the same length andare of the same diameter. When the cylinder I2 is under the plunger 'l the cylinder II projects to one side i of the frame of the press where it is in a position to receive a charge. When the charge in the cylinder I2 has been exhausted, the assembly comprising the sleeve 8 and the arms 9 and the cylinders II and I2 are rotated 180 to bring the cylinder II under the plunger-1 and move the cylinder I2 to the charging position. The assembly can rotate only there being hooklike extensions I3 projecting outwardly from the side of each cylinder. These hook-like extensions alternately engage the column 3, the column 3 being provided with abutments I4 between Which extensions engage and which provide a support for the swingingend of the assembly. This general arrangement of two cylinders pivotally supported is now generally known to the art and this per se forms no part of the present invention. Each cylinder II and I2 has a shouldered opening in the bottom thereof, and a die or die adapter I5 is set into the bottom of each cylinder. Under the tremendouspressure which is used for extruding the material some of the material will sometimes wedge in around the periphery of the member I5, due in many cases to the cylinder Wall being sprung outwardly very slightly under pressure. When thematerial becomes wedged around the member I5 it is very diilicult to remove the member I5. An incidental feature of the present invention provides for the removal of the dies or die adapter I6 when they become so wedged.

On the piston rod 6 of the main ram is an inverted cup member I6 'which has a flange Ilat the bottom thereof and set into this flange is a rubber or other suitable gasket I6. The cup is provided with a gland I9 at the top thereof which provides a sliding fluid-type seal about the piston rod 6. A nipple 26 opening into the cup I6 is connected through flexible tubing (not shown) with a vacuum pump (not shown). I

Compression springs I6a tend to urge the cup downwardlywhile the plunger 1 on the` piston rod 6 provides a means for raising this cup.

In operation, when a cylinder is first brought to position under the plunger 1 the plunger 1 is lowered slightly and the springs I6a force the gasket I8 on the cup I6 into sealing contact with the top of the cylinder I2. This seal is made before the plunger 1 actually enters the cylinder. Before the operation is further proceeded with the space within the cup I6 is evacuated and all removable air which remains in the charge in the cylinder is withdrawn. A vacuum gauge in the line to the vacuum pump may be provided to indicate to the operator when the desired amount of air has been removed.

Mounted on the column 3 below the extrusion die of the press is a sleeve 22 having an arm 23 projecting therefrom. At the outer end of this arm is an adjusting screw 24 having a hand wheel 25. Supported at the top of the screw 24 is a cup member 26 generally similar to the cup member I6, except that the cup 26 is swiveled at the top of the screw 24 instead of there being a gland; th swiveledconnection being indicated at 26a.

The sleeve 22 may be rotated about the column 3 to move the cup 26 from the position shown in full lines in Figure 1 to the position shown in dotted lines. In the latter position the cup projects to one side of the press and is out of the way of the material which is being extruded and out of the way ofthe operator. This cup, like the cup I6, is provided with a nipple 26h that is connected through a flexible tubing (not shown) with a vacuum pump.

In operation, the cup 26 is swung to a position below the extrusion die before the extruding operation has commenced, and the screw 24 is turned to elevate the cup 26 and seal it against the bottom of the cylinder I2. At the same time that air is being withdrawn from the charge at the top of the cylinder, air is also being withdrawn from the charge through the cup 26. When the vacuum gauge indicates that a substantially constant degree of vacuum is being held by the cupsv I6 and 26, and hence that no more air is being released from the charge, the plunger 6 is started down, forcing some of the contents of the cylinder through the die into the cup 26. The motion of the plunger 6 is then stopped; the cup 26 is backed down and the cup 26 is then swung to the dotted line position shown in Figure 1 and the extruding operation is then continued. By forcing some of the charge into the cup 26 before removing the cup the discharge end of the die is plugged by extruded material. Air will not enter through the die to any considerable extent before the extruding operation is started and of course while the material is being forced out under several thousand pounds of pressure the air can not flow back through the die.

Quite as important as the exhausting of the air from the cylinder I2 which is before the.

It has a compressible gasket 29a, and on its lower face a nipple 29h for connection with a vacuum line, and a gland 26e.

Mounted on the column 2, directly under and in line with the line 21, is another hydraulic ram 30, having a. piston rod 3| at the top of which is removably carried a vacuum cup assembly 32 which is substantially similar to the vacuum cup 26 and which has a nipple 33 for connection with the vacuum line (not shown).

In operation, the ceramic mix which is of a granular character and which ordinarily contains only a very small amount of water, the operation usually being a so-called extrusion operation, the vacuum cup 32 is elevated to engage the bottom of the cylinder II. An amount of the ceramic mix is charged into the cylinder at the charging station. When a predetermined amount of material has been charged into the cylinder at the charging station the ram 21 is operated to bring the cup 29 into engagement with the top of the` cylinder in the charging station. Before the plunger 26 enters the cylinder, vacuum may be applied to cup 29 and cup 32 and the loose, granular material in the cylinder can be partially de-aerated. Then the plunger 28 is forced down to compact the loose material after which the ram 21 is operated to open the top of the cylinder, additional material is charged into the cylinder and the cycle repeated on this second batch of charge. Succeeding smaller batches may be added in like manner. It will thus be seen that successive batches are separately introduced into the cylinder and air evacuated therefrom.

During the time that the charge between the cups I6 and 26 is being evacuated the completed charge in the cylinder at the charging station between the cups 29 and 32 is also being evacuated and the vacuum is held `on this charge while the material is being extruded from the main ram. Consequently, most of the air is removed from the material at the charging station and when one cylinder has been emptied the other cylinder is immediately swung to position under the extruding ram. Some air of course will enter the compacted charge as the cylinder is swung from the charging to the extruding position, but this air is removed by the evacuating stage applied throughout cups I6 and 26 and before the extrusion charge begins.

The operation thus described very substantially removes entrapped air from the mix and a superior product is uniformly procured. The invention has very substantially reduced the amount of defective or scrap material.

When it is necessary to remove one of the dies or die-adapters I6, and this member has become wedged .in the cylinder, as herelnbefore described, the vacuum cup I2 may be lifted from the top of the plunger 3I. Pressure may then be applied to the cylinder 30 to force this ram member I5.

While any suitable source of water pressure may be employed for operating the several rams, it is preferable to provide two pumps for operating the main ram. The pump 35 is a low pressure pump of I arge capacity and the second pump 36 delivers a small volume of water at very high pressure. For example, the low pressure pump Inay produce up to 500 lb. per square inch of pressure, whereas the high pressure pump may produce la pressure of around 2000 o r 3000 lb. per square inch. A check valve 31 prevents the high pressure water from going into the low pressure pump. The reason for usingtwo pumps is that in initially moving the plunger and compacting the charge tor be extruded, the rate o'f movement of the ram E is quite fast, so that a large amount of water is required. After this initial compactng operation, however, the plunger moves very slowly and considerable pressure is required. Hence, a very small capacity high pressure pump is used. Both pumps operate continuously and the output of each may be bypassed. According to the present invention, the low pressure 'pump is additionally connected with the cylinders 2l and 30 as indicated by. the dot and dash lines in Figure 1, providing a source of power for these cylinders. The cylinders 21 and 30 may thus be operated with loW pressure water While the high pressure water is being used in the main ram 5 for extruding material.' This arrangement conserves pump capacity and saves energy.

Our invention provides a method and appai holding cylinder, a ram cooperating with the ratus according to which most of the air may be V effectively eliminated from the material being extruded in a vconventional extrusion press. Our invention contemplates a pre-deaeration of the material in the charging station and a final deaeration at the extruding station, and it also provides against the re-entrance of air into the charge once the material is ready to be extruded.

`While We have illustrated and described one particular apparatus for carrying out our invention and have outlined one preferred procedure in practicing our method, it may be understood that various changes andmodications may be made within the contemplation of our invention and under the scope of the following claims.

We claim:

1. Apparatus for extruding ceramic and the like mixes comprising a press having a charge holding cylinder and aram operable in the cylinder for forcing ceramic material from one end of the cylinder, and means at each end of the cylinder movable into and out of engagement with that end of the cylinder adjacent which it is located for withdrawing air from the charge within the cylinder, said means having a sealing surface thereon for contacting the end of the cylinder with which it cooperates.

2. Apparatus for th'e extrusion of ceramic and the like mixes comprising a press having a charge holding cylinder, a ram cooperating with the cylinder for electing the charge therefrom, said ram being adapted to enter one end of the cylinder, the cylinder having an extrusion die at the other end thereof, anda cover member at each end of and outside the cylinder movable into and out of engagement with that end of the cylinder adjacent which it is located for temporarily closcylinder for electing the charge therefrom, said ram being adapted to enter one end of the cylinder, the cylinder having a die at the other end thereof, and a cover member movable into and out of engagement with each end of the cylinder for temporarily closing the ends of the cylinder. and connections leading from the interior of said cover members to a vacuum pump,`the cover mem-ber at one end of the cylinder surrounding said `ram and being sealed about the ram.

4. Apparatus for the extrusion of ceramic and .the like mixes comprising a press having a charge holding cylinder, a ram cooperating with the cylinder for electing the charge therefrom, said ram' being adapted to enter one end of the cylinder, the cylinder having a die at the other end thereof, and a cover member movable into and out of engagement with each end of the Cylinder for temporarily closing the ends of the cylinder,

and connections leading from the interior of said cover members to a. vacuum pump,v the cover member at the die end of the cylinder being movable both axially of the cylinder and transversely with respect thereto.

-5. Apparatus for extruding ceramic and the like mixes comprising a press having a cylinder, a ram which enters the cylinder at one end thereof, the other end of the cylinderbeing provided with a die, a cover member about the ram adapted to be brought into sealing relation with the end of the cylinder into which the ram enters, and a second cover member at the die end of the cylinder movable axially into and out of engagement with the die end of the cylinder, said cover members having connections through which they may be connected to a vacuum pump whereby the charge end of the cylinder may be evacuated.

6. Apparatus for extruding ceramic and the like mixes comprising a press having a charge containing cylinder, said cylinder being movable from a charging position to an extruding position, a ram on the press which enters one end of the cylinder at the charging position for compacting the charge in the cylinder, a second ram on the press positioned to enter one end of the cylinder and expel the charge therefromv when the cylinder is in the extruding position, and means for evacuating air from both ends of the charge in the cylinder in both positions.

7. Apparatus for extruding ceramic and the like mixes comprising a press having a charge containing cylinder, said cylinder being movable from a charging position to an extruding position. a ram onthe press which enters one end of the cylinder at the charging position for compacting the charge in the cylinder, a second ram on the press positioned to enter one end of the cylinder and expel the charge therefrom when the cylinder is in the extruding position, cover members about both of said rams movable with the rams into and out of sealing engagement with one end of the cylinder, and movable cover members on the press movable into and out of engagement with the other end of the cylinder,one engaging the cylinder in the charging position and one engaging the cylinder in the extruding position, all of said cover members having connections adapted to be connected with a vacuum pump.

8. Apparatus for extruding ceramic and the from a charging to an extruding position, a ram on the press which enters one end of the cylinder at the charging position for compacting the,`

charge in the cylinder, a second ram on the press positioned to enter one end of the cylinder and expel the charge therefrom when the cylinder is in the extruding position, the cylinder having a die at the other end thereof, cover members about both of said rams movable with the rams into and out of sealing engagement with one end of the cylinder. and movable cover members on the press movable into and out of engagement with the other end of the cylinderY one engaging the cylinder in the charging position and one engaging the cylinder in the extruding position, all of said cover members having connections adapted to be connected. with a vacuum pump, the cover member which engages the die end of the cylinder in the extruding position being movable both axially and transversely with respect to the cylinder.

9. Apparatus for extruding ceramic and the like mixes comprising a press havinga charge containing cylinder, said cylinder being movable from a charging position to an extruding position, a ram on the press which enters-one end of the cylinder at the charging position for compacting the charge in the cylinder, a second ram on the press positioned to enter one end of the cylinder' and expel the charge therefrom when the cylinder is in the extruding position, the cylinder having a die at the other end thereof, cover members about both of said rams movable with the rams into and out of sealing engagement with one end ofthe cylinder, movable cover members on the press movable into and out of engagement with the die end of the cylinder, one

engaging the cylinder in the charging position and one engaging the cylinder in the extruding position, all of said cover members having connections adapted to be connected with a. vacuum pump, and a ram mounted on the press for supporting the cover member which engages the die end ofthe cylinder in the charging position for moving the cover member axially of the cylinder into and out of engagement therewith.

10. Apparatus for extruding ceramic and the like mixes comprising a press having a charge containing cylinder, said cylinder being movable from a charging position to an extruding position, a ram on the press which enters one end of the cylinder at the charging position for compacting the charge in the cylinder, a second ram on the press positioned to enter one end of the cylinder and expel the charge therefrom when the cylinder is in extruded position,rthe cylinder having a die at the other end thereof, cover members about both of said rams movable with the rams into and out of sealing engagement with one end of the cylinder, movable cover members on the press movable into and out of engagement with the die end of the cylinder, one engaging the cylinder in the charging position and one engaging the cylinder in the extruding position, all of said cover members having connections adapted to be connected with a vacuum pump, and a ram mounted on the press for supporting the cover member which engages the die end of the cylinder in the charging position for moving the cover member axially of the cylinder into and out of engagement therewith, the cover member on said last named ram being removably secured to the ram whereby the ram may be used to press against the die in the die end of the cylinder.

SEMON H. STUPAKOFF. RAWSON E. STARK.

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