DE2038413A1 - Vertical closing press for injection molding of thermoplastic, thermosetting and elastomeric material - Google Patents

Description

M.A.S. Hydraulic and Vulcanizing Machinery co. S.r.L. Via Moroni 4 Milan / Italy

Vertical closing press for injection molding of thermoplastic, thermosetting and elastomeric material

The invention relates to a vertically closing press for Injection molds of thermoplastic, thermosetting and elastomeric Material.

It is known that presses of this type are increasingly used are because of the advantages they have over horizontally closing injection molding presses, viz

a) Possibility of using light or heavy, single or multiple molds with or without removable mandrels,

b) Possibility of using structurally simple and therefore cheaper forms,

c) no or no significant influence of the mold weight on the Pormsohließeinriohtung,

d) significant reduction in the size of the press.

Vertical closing injection molding presses, as they are currently are in use, consist essentially of a vertically extending frame, a pair of vertically extending

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directed form-carrying punches, at least one of which in is movable in the vertical direction, and a device, preferably of the type of a screw conveyor for introduction a measured amount of a malleable material in a transition chamber. In vertically closing presses, the movement of the movable standard support stamp is also effected With the help of hydraulic Eolben cylinders. To this end carries the frame at a point above, particularly in presses in which the movable mold is the upper mold of the upper punch a pair of piston cylinders to allow the upper mold to approach the lower mold quickly effect, and another piston cylinder for holding the molds together during injection molding of the elastomer Materials. The last-mentioned cylinder is usually of large size because of the high pressures that occur during the injection molding of the material and which are aimed at the molds from their closed Position to move out. In addition to the above Cylinders has a vertically closing press on top of the frame at least one storage container for the hydraulic operation of the cylinder required fluid.

The construction described above is the usual vertical closing Pressing is disadvantageous because of the high level of piston cylinder entrainment and oil tanks caused by weight,

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that at a given height and also with regard to the large amount of circulating oil necessary for satisfactory Work of the press is required, must be carried by the frame. As a result, one should be vertical Closing press, in order to ensure sufficient operational stability, necessarily built particularly strong especially if the press is designed for a large daily output. ·

It is also known that injection molding presses in general are equipped with two relative to each other movable mold support stamps, each with one one Impression of the workpiece to be shaped exhibiting porm half connected is.

Depending on the size of the workpiece, the two 3-shape halves are naturally different in height, see above that the stroke of the molded parts for closing and subsequent opening of the Eorm, as well as the stroke of a punch for " Creation of the closing pressure changed and according to the height the shape should be adjustable.

This requirement is met in conventional injection molding presses Taken into account that long working stroke for the piston both for approaching and retracting the punch as well as the Piston for exerting the closing pressure on the stamp

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be seen. Since the last-mentioned piston works in a cylinder of large cross-section, this is for exercise a sufficient closing pressure required oil volume at a given working pressure larger if it depends on the height of the mold used for both large and small stroke lengths should be sufficient.

The circumstances described lead to operational difficulties and make those actuating the mold too large and parts carrying the working fluid are required.

The invention relates to a vertically closing injection molding press for thermoplastic, thermosetting and elastomeric material, preferably raw rubber, in the case of the one described Deficiencies are countered in that oversized and heavy, the usual presses peculiar constructions avoided and an improved operation compared to the usual presses as well as greater flexibility in its implementation are guaranteed. The invention also relates to an injection molding press with which it is possible to produce shapes to use of different heights, the working stroke of the mold clamping and clamping piston constant and of the smallest length, whatever the height of the shape may be.

The 10981 A / 18 19 according to the invention exists to achieve this goal

Injection molding press consisting of a frame extending in the vertical direction, a pair arranged one above the other in the frame Form support stamps, hydraulically operated means for achieving a rapid approach of the upper stamp to the lower spray nozzle, one extending upwards through the lower punch, and one to the attached lower punch, arranged in alignment with the, spray nozzle and connected to it Transition chamber for mouldable material and is characterized in that a vertically constructed piston-cylinder unit is arranged in the frame below the transition chamber whose movable element is attached to the lower punch and the cylinder of another vertical arranged cylinder unit forms the piston rod end is designed as a piston and slidably tightly guided in the transition chamber, and that continues to be a fixed feed screw unit connected to the movable element of the first-mentioned cylinder unit for introducing a | predetermined amount of malleable material in the transition chamber, further means for interrupting the flow of material into the chamber during injection and finally Means for separating the transition chamber and the spray nozzle when the material is introduced into the transition chamber are provided.

The press according to the invention is also characterized by this 109818/1819

indicates that it has at least one adjustable support device connected to buckets of the first stamp, means for moving the stamp together with the support device for approaching and closing the mold, fixed support means on the frame, with the mold closed and effective in the control of the mold closing pressure and has a piston connected to a second punch, by means of which the pressure required for closing and holding the bag is applied in that it carries out a constant work shub in its pressure cylinder regardless of the height of the mold arranged between the punches.

The invention also provides a two-way valve for automatic Opening and closing of the irbergaagskammer. That The valve first connects the transition chamber with the feed for plasticized material. Then it changes the connection and allows the material, rom. the transition chamber eimanatireten into the mold via the spray nozzle;

After the valve has been designed, material can be used when the form is open for the purpose of de © Ämstrages a finished fitting as a result of an ÜberlajDjpmg in the Transitional chamber are introduced. A second land third Execution works without overlapping, jecLoeli has more significant ones, lying in the simplicity of the constructions Advantages.

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The invention is based on the drawing on a Embodiment described.

Fig. 1 shows a view of the device in teilgeschnit th representation. In Fig. 2, a support device is in reproduced in perspective representation. In Fig. 3 the lower part of the device shown in Fig. 1 is in one Partial section shown. 4, 5 and 7 show sectional images of three different valve designs. In Fig. 6, the valve member of the valve shown in Fig. 5 is shown in perspective. Fig. 8 gives a section on the line VIII - VIII through Fig. 7 again.

The injection molding press shown in FIGS. 1 to 3 consists from a frame 1 which extends in the vertical direction and which carries the various work equipment.

At the bottom of the frame there is a simple one resting on supports 3 Acting cylinder 2 for closing and keeping the mold closed with the aid of a piston 4 is arranged. With 4a and 4b (Fig. 3) are designated sealing rings. The piston 4 is hollow and represents a double-acting cylinder 5, the inlet and outlet openings 5a and 5b provided and in deif "a piston 6 with sealing rings 6a and 6b is performed. The end 7 of the rod 8 of the piston 6 is guided and slides tightly in a transition chamber 19

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acts as an injection piston for the casting material.

The hollow piston 4 extends upwards and carries a lower punch 9 and by means of one in a fixed guide 11 guided arm 10 a device for plasticizing and conveying the material. This device consists of a motor 12, which by means of a belt 13 and Drive wheels 14 in a cylindrical housing 16 drives a screw conveyor. The material enters through you Filling funnel 17 is located in the cylindrical housing 16 under the action of heat, which is supplied via a heating jacket, plasticizes and passes through a valve 19a in the transition chamber 19, from which the material under the action of the end 7 of the piston rod 8 by means of an injection nozzle 22 and via an inlet bore 23 in the mold 20 is injected into the cavity 21 of the mold.

The mold consists of two mold parts 20a and 20b, of which the part 20a with the lower punch 9 with intermediate arrangement a mold discharge device so connected is that it can be periodically removed from the machine if the machine's work sequence requires it, after the injection nozzle has been moved out of its working position.

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The mold discharge device "consists of a mold support plate 24, which is connected to the piston rod 25 of a hydraulic cylinder 26, which from one of the frame 1 projecting arm 27 is carried.

The upper mold part 20b is supported by an upper stem pel 28, which also generally includes a pair of adjustable supports to meet mold clamping pressure

29 designated, is assigned. Each of the devices 29 consists (Fig. 2) of a rigid base block 30, the firmly seated on a plate 31, which is transverse to the direction of movement of the punch 9 and 28 in guides, not shown is slidably disposed on the upper punch 28. The sliding movement is effected by hydraulic cylinders 32, which are fastened on bearings 34 extending from the punch 28.

With 36 (Fig. 2) compensating pieces are referred to with Using screws 35 on top of each other and on the base block

30 can be attached and the same height correspond to a partial height of the base block. Each leveling piece 36 is placed on top of the piece below for bin disassembly and assembly.

The upper punch 28 with its support devices 29 1st through, a piston rod 37 of a hydraulic cylinder

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38, the approach and retreat of the, upper Punch 28 to and from the lower punch 9 ″ caused vertically displaceable. The cylinder 38 is carried by the upper part of the frame 1.

At the greatest height that can be reached by the adjustable support devices 29, the frame has a head piece 39 _y which is provided with an opening 40 through which the piston rod 37 passes. In the closed position of the mold, the cylinders 32 cause the devices 29 to come under the head part 39 (fully drawn position in Pig. When the mold is opened, since the piston 4 moves downwards, the support devices 29 are first lowered together with the punch 28 and then guided out of the space under the head part 39 by a short lateral displacement caused by the cylinders 32, whereupon the upper Stamp 28 can be lifted.

In order to replace the shape with a shape of a different height, for example against a shape whose height exceeds the shape shown in FIG To create space for the inclusion of the other form.

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If the height difference between the old and the new mold is not exactly the height of one or more leveling pieces 36 corresponds, an additional adjustment of the stamp can be made with the aid of the piston 4 be, its position in the cylinder 2 by bin- or draining a certain amount of liquid through the opening 2a can be easily adjusted into the cylinder. Accordingly, the allowable stroke of the piston 4 in the cylinder becomes at least equal to the height of one of the compensation pieces ^ 36 of the support device 29. If the punch accordingly the changed height of the mold 20 are set, the mold closing and pressing stroke still effected by the piston 4 be the same as before and as directed at the press.

From this it follows that a rough adjustment of the press to a change in the height of the mold on the change in height of the devices 29 is based and that the closing stroke, caused by the pressure cylinder (if necessary after a fine adjustment) remains constant, whatever is the height of the new shape.

The valve shown in Fig. 4 for interrupting the entry of material into the transition chamber 19 consists of a double-acting hydraulic cylinder 270 with 01 inlets 280 and 290 and a removable floor 300, the

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is held by a screw ring 30Oa, as well as from a piston 310, which is slidably guided in the cylinder 270 and is provided with sealing rings 320 and 330. The piston 310 is attached to a piston rod 340 which passes through a removable end piece 370 protrudes axially therethrough from the cylinder. The protruding part of the piston rod has a constriction 350 and a head part 360 with a lateral bevel 361. The removable end piece 370 is held in the cylinder 270 by a screw ring 380, which by means of a cylindrical part 390 with External thread in (cf. FIG. 3) a recess 250 in the extension 4c of the cylinder which forms the transition chamber 19 4 can be screwed in. The head portion 360 is dimensioned so that it fits exactly into the passage 19b, the the screw conveyor 16 and the transition chamber 19 connects to one another, so that the supply of plasticized Material is stopped when the piston 310 is in the forward position. The head 360 continues to interrupt the connection between the transition chamber 19 and the overlying injection nozzle 22 in the retracted position of the piston 310, although the known overlapping technique is possible, as is the transition chamber 19 to fill in the open position of the mold.

In FIGS. 5 and 6, a further embodiment of a valve 19a is shown. Chamber 19 opens at this point

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axially into a channel 301 leading to the spray nozzle and the extension part 4c is diametrically opposed to the channel 301 provided hole 401 cutting at right angles. The cutting area is denoted by 501.

In the right-hand part of the bore 401, a rod 601 is guided, which is connected to a recess 801 of the Part 4c screwed screw head 701 is provided. The end portion 901 of the rod 601 which extends through the gap 501 is preferably in the form of a cylindrical pin, the diameter of which is less than the diameter of the bore 401, so that a annular passage from the chamber 19 to the channel 301 is formed.

In the left-hand part of the bore 401, a connecting piece 101 is screwed into a recess 121 with an internal thread 131. The connecting piece has a line 141 which opens into the bore 401 via an opening 151 via which the casting material plasticized in the plasticizing device is introduced into the chamber 19.

In the space 181 between the end face 161 of the connecting piece 101 and the end face 171 of the pin 901 there is a valve member 191 'which is freely movable in and out. This valve element consists (see Pig. 6)

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-H-

from a longitudinal body 201, on the circumference of which a number of axial ribs 211 extend, the free corners of which open an imaginary cylindrical surface with a diameter

is
ser lie, which is slightly smaller / than the diameter of the space 181 in which the member 191 is consequently freely displaceable. The ends 221 and 231 of the valve member 191 are frustoconical so that the conical surface 241 - as indicated by broken lines in FIG. 5 - fits into the opening 151 in the connecting piece 101 in order to close this opening.

The valve described above works automatically under the action of the material to be molded. In the work stage, in which the plasticized material is fed through the line 141 in the connector 101, the material pushes the valve member 191 to the right until it hits the surface 171 of the pin 901. In this position the material flows through the grooves between the Ribs 211 and passes through the annular passage 501 into the transition chamber 19. When the chamber 19 is full and the spraying begins, the material is removed from the plunger 7 (not shown in FIG. 5) is pressed closed via line 301 of the spray nozzle. The material pressure shifts here the valve member 191 so that it is the inlet port 151 closes. In this way, the material is fed to channel 301 only.

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It is important to note that the plasticized material is subjected to a further plasticizing operation during its introduction into the chamber 19 in that it is extruded through the grooves between the ribs 211 of the valve member 191. An overlap event finds however, not because the mold must be closed before the chamber 19 can be loaded.

7 and 8, which show a further Yentilausführung ™ gen, the parts which correspond to the parts shown in Figs. 5 and 6 are given the same reference numerals as provided there. Instead of the valve body 191, a ball 251 is provided in this embodiment, which in the Bore 181 freely movable under the action of the flow of material between the opening 151 and the end 261 of the pin 901 is. The end 261 has radial wings 271 which contact the inner wall of the bore 181 and between them Free passages 281 through which the Ma- | material reaches the transition chamber 19. In this version the transition chamber 19 can also only be filled when the mold has been closed.

From the above description it can be seen that the vertically closing press according to the invention fully meets the above task, in particular by a improved operation, reduced size for one with

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work performance comparable to conventional presses, high stability even during prolonged activity and easy access to all parts, which facilitates operation and adjustment.

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Claims (8)

- 17 claims: Injection molding press for thermoplastic, thermosetting and elastomeric material, preferably rubber, consisting from a frame extending in the vertical direction, a pair of mold support rams arranged one above the other in the frame, hydraulically operated means for achieving this one rapid approach of the upper to the lower punch, one axially through the lower one Piston extending through the spray nozzle and one attached to the lower punch, in the same direction the spray nozzle arranged and communicating with it transition chamber for the material, characterized in that, that a piston-cylinder unit (2/4) is arranged in the frame below the transition chamber (19) is, the movable element (4) is attached to the lower punch (9) and the cylinder (5) one forms another cylinder unit (5/6) arranged above it, the piston rod end of which is designed as a piston (7Ü) and is guided so that it slides tightly in the transition chamber, and that further a screw conveyor connected to the movable element (4) of the lower cylinder unit (18) for introducing a predetermined amount of material into the transition chamber, further means (191 »360, 251) to interrupt the flow of material into the 10 9 818/1819 passage chamber during the injection process and χϊχχχχ jcxxxxx to interrupt the connection between the transition chamber and spray nozzle are provided when the material is introduced into the transition chamber. 2. Injection molding press according to claim 1, characterized in that it has at least one adjustable support device (29) connected to an upper punch (28), means for moving this punch together with the support device for approaching and closing the mold (20) on which The frame has fixed support means (39) which are effective when the mold is closed and in the direction of the closing pressure of the mold and a piston (A) connected to a lower punch (9) through which the piston (A) required for closing and keeping it closed in Hub is applied for what purpose he / his Printing cylinder (2) regardless of the height of the mold arranged between the punches with a constant stroke length emotional. 3. Injection molding press according to claim 2, characterized in that the adjustable support device consists of one with the associated stamp (28) connected to the base block (30) of a certain height and of a number consists of compensating pieces (36), one on top of the other are arranged on the basic block, and that 109818/1819 Means are provided for fastening the compensating pieces among each other and the lower compensation piece on the base block. 4. Injection molding press according to claims 2 and 3, characterized in that the support means (39) firmly connected to the frame consist of a head part which receives the closing pressure of the mold and which is rigidly attached to the frame and in that, in order to open the mold g to enable means (32) are provided for moving the supporting device out of its supporting position. 5. Injection molding press according to claims 1 to 4, characterized in that that the piston exerting the closing pressure (4) in its cylinder (2) executes a stroke, the length of which is the same as the height of at least one that corresponds to the base block associated compensating pieces (36) corresponds. 6. Injection molding press according to claims 1 to 5, characterized in " characterized in that to interrupt the connection A double-acting piston valve (19a) is arranged between the transition chamber (19) and the spray nozzle (22) during the introduction of material into the transition chamber and to interrupt the introduction of material during the injection process above the transition chamber, the piston rod (340) of which in its from the Cylinder (370) protruding part has a constriction (350) 109818/1819 and ends in a head piece (360) with a lateral bevel (361) which is dimensioned so that it is the Material inlet in the transition chamber closes or the The connection between the transition chamber and the spray nozzle is interrupted, the constriction in the cutting area (501) of the Transition chamber and the spray nozzle is located. 7 · injection molding press according to claims 1 to 6, characterized characterized in that a two-way valve is provided for the automatic opening and closing of the transition chamber, consisting of a channel (401) which cuts the connection between the transition chamber and the nozzle. one the canal Pin (601/901) that closes at one end and protrudes behind the cutting area, its in the cutting area lying cross-sectional area smaller than the cross-sectional area of this area iet, one at the other end of the channel arranged pierced connection piece (101) leading to the material supply, which is at a distance is supported by the end (171) of the pin in the channel, a valve member consisting of a longitudinal body. (191) with a number of axial ribs (211) on the outer surface, which can move freely between the support surface (161) of the Connecting piece and the end (171) of the pin is arranged and that when inserting material into the Transition chamber or when transferring the material 109818/1819 the transition chamber into the spray nozzle, the inlet opening (151) of the connector under the action of the material opens or closes. 8. Injection molding press according to claims 1 to 6, characterized in that a double-acting valve is provided for the automatic opening and closing of the transition chamber, consisting of a channel (181) intersecting the connection between the transition chamber and nozzle, ä one closing the channel at one end and pins (601/901) protruding beyond the cut area, the end of which has a number of radial ribs (271) extending to the inner wall of the channel and whose cross-sectional area in the cut area is smaller than the cross-sectional area of this area, one at the other end of the channel arranged through the material supply serving connecting piece (101), which is supported at a distance from the end of the pin in the channel, a ball-like valve body (251) with a smooth surface, which can move freely between the support surface (161) of the connecting piece and the pin end is arranged and that when introducing material into the Übergan g chamber or when transferring the material aue the transition chamber into the spray nozzle, the inlet opening (151) of the connector opens or closes under the action of the material. 109818/1819