US2373167A - Extrusion apparatus - Google Patents

Description

A ril 10, 1945. e. CHERRY ET AL EX'I'RUSION APPARATUS Filed March 31, 1943 INVENTORS GLCHEERY C. C. VE/ILE HTTOE/VEY Patented Apr. 10, 1945 EXTRUSION APPARATUS George L. Cherry, Western Springs, and Charles C. Veale, Wheaton, Ill.,,assignors to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application March 31, 1943, Serial No. 481,212

2 Claims. (Cl. 25- -16) til the piston encounters a predetermined amount 2 of resistance to its movement and then the high volume, low pressurepump is automatically cut out of operation. In this apparatus, a manually controlled valve may be operated to direct fluid under pressure to opposite sides of a slidable control valve which, in turn, will direct fluid to one side or the other of a piston which actuates the extrusion plunger, and the apparatus may be loaded through an air-tight door which, when closed, closes a circuit to connect the extrusion chamber to a vacuum system and to render the extrusion plunger operable.

A better understanding of the invention may be had by reference to the following detailed description when considered in conjunction with the accompanying drawing, wherein the single figure illustrates diagrammatically a preferred form of the invention.

In the drawing, there is shown an extrusion chamber I, having an extruding die 2 suitably attached in its left end whereby ceramic material which has been placed within the chamber I may be extruded through an orifice 3 in the die 2 to form ceramic rods which may be later fused. Attached to the righ end of the extrusion chamber is a loading chamber 4 having formed integrally with it a guide portion 5 for guiding an extruding plunger 6 into the chamber I for forcing a mass or ceramic material (not shown) through the die orifice 3.

The loading chamber 4 is provided with a suit able air-tight door I, which may be raised to permit the loading of material in the loading chamher. The door 1 may be hinged in any suitable manner so that when closed, it will seal the loading chamber. In communication with the chamher 4 is an exhaust pipe 8. having a shut-on valve 8 connected in it. The valve 9 is adapted to be actuated by a solenoid ID of any suitable type when the door I is closed so that a vacuum pump (not shown) connected to the exhaust pipe 8 may create a vacuum in the chamber 4 to prevent the entrapment of air in the rod extruded by the plunger 6, forcing the material through the die orifice 3. The door 1! has mounted on it a lever ll, carrying a contact actuating element l2 in position to close a pair of contacts l3 when the door is closed. One side of the winding (not shown) of the solenoid 10 is connected to one side of a current source Hi and the other side of the winding of the solenoid may be connected through the pair of contacts iii to the other side of thecurrent source M when the door 'i is closed.

In addition to controlling the supply of current to the solenoid ill, the pair of contacts !3 also control the supply of current to a second solenoid l5, which is connected to a shut-off valve it. The shut-off valve it is normally closed and will normally prevent fluid from passing through a pipe H in which the shut-oil valve i6 is inserted. The pipe ii.extends from a port i8 in a cylinder head id to a port 20 in a slide valve 2! and thus the shut-oil valve it controls the flow of fluid in either direction between a cylinder 22, in which the cylinder head it is mounted, and the slide valve ii. The cylinder 22 has a piston 23 mounted for reciprocation on it and the piston 23 is connected to the end of the extruding plunger 6 so that when the piston 23 is actuated, the plunger 6 .will move with it. In addition to the port 88 communicating with the interior of the cylinder 22 through the cylinder head l9, the left end of the cylinder has a port 24 formed in it. The port 241s interconnected with a port 25 in the slide valve 2! by a pipe 26 and either the port 20 or theport 25 may be connected in communication with a port 27 by a passageway 28 formed in a slidable valve member 29, depending upon the position of the valve member 29 in the slide valve 2 l. Also formed in the valve member 29 are a pair of passages 30 and 3| and when port 21 is connected with port 25, the passageway 3| will be inoperative, but hassage 30 will then connect the port 20 to a port 32 in the slide valve 2|. Conversely, the passageway 30 will be inoperative and the passageway 3! will interconnect the port 25 withthe port 32 when the valve member 29 is shifted to a position where the passageway 28 will interconnect ports 20 and 21.

The valve member 29, in effect, constitutes a piston which may be shifted from the right end of the slide valve 2| upon the admission of fluid under pressure to the right end of the slide valve.

. The right end of the slide valve 2! is in com- The pipes 4| and 42 interconnect the slide valve 2| with diametrically opposed sides of a manually operable valve 43, which, when in the position shown, will block the flow of fluid in any direction through it. The valve 43 has three different positions in which it may be set, as indicated by the solid and dot and dash line positions of a handle 44. In addition to the pipes 4| and 42 extending to the manually operable valve 43, there are a pair of pipes 45 and 46 connected thereto. The pipe 45 is connected by a T-connection 41 to a pair of pipes 46 and 46, whereas the pipe 46 is connected through a T-connection 56 to a pair of pipes and 52. The pipe 43 serves to com meet both the pipes 45 and 49 to a high pressure, low volume pump 55 connected-to be driven by a motor 56 and adapted to draw fluid through a pipe 51 from a supply tank 56. The pipe 5| serves to connect the pipes 43 and 52 to the tank 56.

A T-connection 60 connected to pipe 48 interconnects the pipe 49 and a pipe 6| through a pipe 62 to the port 21. The pipe 6| serves to suppl fluid under pressure from a high volume, low pressure pump 63 adapted to be driven by a motor 64 and drawing fluid from the supply tank 56. The pipe 6| has in it a check valve 65, which will prevent fluid from travelling in the direction opposite to the arrow 66 through the pipe 6| and the pipe 6| also has mounted in it a pressure responsive switch I0, which, when the pressure in the pipe 6| reaches a predetermined value, will actuate a contact II to disconnect the motor 64 from the power source l4, although the pair of contacts |3 may be closed. Power for driving the motors 56 and 64 may be supplied from the current source l4 by closing a switch 15. However, the handle 44 must be operated to effect a shift 01' the valve member 23 which i normally urged to a mid position in the slide valve 2| by a spring I6, which normally holds the member 29 in mid position to block ports 26, 25, 21 and 32.

A more complete understanding of the invention may be had by reference to the following brief description of the mode of operation thereof. In order to place the apparatus in condition for operation, switch may be closed to supply current to motors 56 and 64 and the manually operable valve 43 may be shifted to position 3, where pipes 45 and 4| will be interconnected and pipes 46 and 42 will be interconnected through the passageways shown in the valve 43. After the apparatus has thus been placed in condition for operation, a supply of ceramic material to be extruded may be placed in the loading chamber 4 and as soon as the door 1 is closed, the pair of contacts l3 will complete a circuit to supply current from the source l4 to the solenoids Ill and 5. Since the valve 43 has been shifted to position to interconnect pipes 4| and 45 and pipes 42 and 46, fluid under pressure will be directed from both of the pumps through pipes 45 and 4| to shift the slidable valve member 23 to the left. As soon as the slidable valve member 26 is shifted to its lefthand position, the passageway 26 will interconnect ports 26 and 21 and the passa eways 36 and 3| will interconnect ports 25 and 32. With the slide valve in this position, both of the pumps will supply fluid under pressure through the port 21 to passageway 28 and through passageway 28 and port 20 to pipe ll, thereby to direct the fluid under pressure to the right hand side of the piston 23. The piston23 will force the ceramic material placed in the loading chamber-4 over to a point where the ceramic material engages the extruding die 2 since the closure of the pair of contacts |3 opened the shutoff valve I 6. The travel of the plunger 6 will be relatively rapid since both the pump 58 and the pump 63 will be supplying fluid under pressure to drive the piston 23. As soon as the plunger 6 encounters an appreciable amount of resistance, due to the engagement of the ceramic material with the extruding die 2, back pressure will be built up in the pipe 6| and since the fluid cannot travel opposite to the direction of the arrows 66 in pipe 6|, check valve 65 will automatically close and the pressure responsive valve 16 will open it contact 1|. When the contacts open, the motor 64 will he cut out of operation and the continued travel of the plunger 6 to the left will be at an appreciably slower rate, but at a higher pressure. Thus, the plunger 6, when the resistance to its movement is relatively low, will travel at a high rate of speed and as soon as the resistance to the movement of the plunger 6 increases to a predetermined amount, the travel of the plunger will be slowed down and will continue under the operation of the pump 55.

As soon as a charge placed in the appartus has been extruded through the die orifice 3, the handle 44 may be moved to position I, where the pipes 4| and 46 will be interconnected and pipes 42 and will also be interconnected, thus to supply fluid under pressure to the left side of the slide valve member 23 and restore the slide valve 2| to its right hand position. When the slide valve 2| returns to the right hand position in the drawing, the pressure at T-connection 63 will drop and the pressure responsive switch 13 will close its contact H, thereby to cut the motor 64 back into operation and the return of the piston 23 to the position shown will be eflected by fluid forced through the pipe 62 by the combined operation of the pumps and 63. When the piston 23 returns to normal position, as shown, the valve" may be restored to the. position shown, thus cutting off the supply of fluid under pressure to operate the slide valve 2| and the air tight door I may be opened to permit another charge of ceramic material to be placed in the loading chamber 4. When the door I is opened, the pair of contacts l3 will be opened to close the shutofl' valve 9 through deenergization of the solenoid l6 and to close the valve l6 through the deenergization of the solenoid l5. When this condition prevails, thespring I5 will move the slidable member 23 to normal position, as shown.

Whatisclaimedis:

1. In an extrusion apparatus, an extrusion chamber having a charging opening in a wall thereof, a closure member for said charging opening, a piston for actuating an extrusion plunger, a cylinder for said piston, a high pressure low volume pump and a low pressure high volume pump for supplying fluid pressure to said cylinder, a motor drive for each of said pumps, means responsive to the position of said closure member for controlling the admission of fluid to said cylinder from said pumps, and an electric switch responsive to fluid pressure in said cylinder for controlling the actuation of the motor drive for said high volume pump. I

2. In an extrusion apparatus, an extrusion chamber having a charging opening in a wall thereof, a closure member for said opening, a piston for actuating an extrusion plunger, a cylinder for said piston, a high pressure low volume pump and a low pressure high volume pump for supplying fluid pressure to said cylinder, a motor drive for each of said pumps, means responsive to the position of said closure member for controlling the admission of fluid to said cylinder from said pumps, and electric switch 5 responsive to fluid pressure in said cylinder for controlling the actuation of the motor drive for GEORGE L. CHERRY. CHARLES C. VEALE.

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