DE2301088A1 - DEVICE FOR MOLDING OBJECTS FROM THERMOPLASTIC MATERIAL - Google Patents

Description

The invention relates to an apparatus for molding thermoplastic material, and more particularly to an apparatus of the type in which a parison obtained by injection molding is divided into a blow mold can be, introduced and inflated in this to form a hollow body that has the shape of the Is adapted inside the blow mold.

In the manufacture of objects by the injection-blow molding process the parison must first be manufactured by injection molding, followed by cooling of the parison for its transfer to a blow mold follows, in which pressurized gas, usually air, into the

309829/0390

H2 117

Külbel is granted access to the shape of the Expand inside the blow mold. This technique is of particular value when molding plastic bottles, because the neck of the bottle with or without screw thread is formed during the injection molding process and then in the Neck portion of a blow mold can be held so that the blow molding portion of the process is only used to shape the Body part of the bottle is executed »

The injection / blow molding process has been suggested run in a machine in which a plate has a mandrel on its opposite sides to the simultaneous cooperation, one with an injection molded part to form a parison on the core and the other with a blow mold. The plate is rotated 180 ° after each injection / blow molding process. This suggestion however, it has the disadvantage of a slow workflow, since a second parison only goes back into the blow mold can be introduced after the previous blow molding has cooled and ejected and in practice, the time taken for blow molding and subsequent cooling and ejection is essential longer than the time required for an injection molding process with subsequent cooling and removal the injection mold is required. The machine's output is therefore limited.

The main object of the invention is to provide an injection / blow molding machine with which the output in the Compared to the previous proposal can be increased significantly and in which a conventional injection molding machine can be used for an injection / blow molding process by a relatively simple conversion

309829/0890

H2 117

can which conversion, if necessary, an inversion can learn to convert the injection molding machine back for a conventional injection molding process.

A device according to the invention for shaping objects made of thermoplastic material has plates, one of which is rotatable with each of two faces Turret is connected and from each of which at least one core protrudes, which surfaces in the are at right angles to each other and are parallel to the axis of rotation, a stationary injection mold whose center line passes through and is perpendicular to the axis of rotation of the turret, a device for conveying molten thermoplastic material to the injection mold, an actuating device that does this serves, the turret along the center line of the injection mold in and out of the shaping position to this to move a turret turntable while can be operated alternating periods during which the turret from the shaping position to Injection mold is retracted to the turret by 90 in one direction during the mentioned one Period to rotate and in the opposite direction during the next period, two blow molds connected to each other are aligned and have a common center line that is perpendicular to the center line of the mold is and passes through the axis of rotation of the turret when a plate of the latter is in the Molding position with the injection mold is located, a blow mold moving device, which is used to move the blow molds alternately along the mentioned common center line in the blow molding position to the turret head

309829/0890

1 * 2 117

because of when the latter is in the foreground position to the injection mold, and a device that serves to supply compressed gas to a core or cores, which protrudes from the plate or protrudes, which cooperates with a blow mold.

An embodiment of the invention is as follows For example, in connection with the accompanying schematic drawings, namely show:

1 shows a side view of the device according to the invention in a schematic representation;

FIG. 2 shows a plan view of FIG. 1, with some parts being omitted for the sake of clarity; FIG.

Fig. 3 is an end view of Fig. 2 in the direction of arrow A, but showing some parts in positions which are different from those which they take in Fig. 2, while others Parts are shown broken away;

Fig. 4 in a schematic representation a plan view, which shows part of the operating mechanism of the device;

Fig. 5 is a view in section and with broken away Share a core-bearing turret in its position in which it is full of the Cooperation with an injection mold is withdrawn;

Figure 6 is a top plan view of the parts of Figure 5;

Fig. 7 is a sectional view showing a detail of the ¹

309 82 9 7Ό ⁴ 890

Device shows, and

Fig. 8-2 $ in schematic representation the sequence of Operations during a complete cycle the same.

The rotatable Revelyerkppf 1 shown in the drawings has two surfaces 2, 3 {Tig. · Ό »which are perpendicular to each other and parallel to the vertical axis of rotation. At least one core -H or $ extends from each of the surfaces 2, 3 and the cores are supported by plates P (Figures 2 and H) which can be removed from the surfaces 2, 3 to allow the cores to be opened as the case may be forming object can be chosen * Each plate P can be stranded with only a single core, but usually carries several cores, for example four cores arranged in a line, as indicated in Figs. 2 and 6, or two in a 14-ni.e arranged cores, as shown in Fig. ff. Furthermore, if desired, each plate can carry two or more rows of cores arranged one above the other as shown in FIG.

The axis of rotation is on the center line S, which runs through the surface of an injection mold 7, in which parison 8 (FIGS. 8-28) around the cores for the upper guide through this to one or the other of two blow molds 9, 10 are formed, in which the parisons on the Shape of the interior of the blow molds are molded. the Injection mold and blow molds are each provided with a number and arrangement of mold cavities, which the The number and arrangement of the cores on a plate P correspond.

Me blow molds can, if desired, split molds be »which in any suitable manner (not shown) can be opened and closed, although the in 1-7 are not split molds.

The injection mold 7 is in a fixed position on the Arranged frame of the machine, which is denoted generally rait F in Fig. 1 and 3, which injection mold a suitable known form of a plasticizing and injection unit 11 is assigned, through which molten thermoplastic material is fed to the injection mold. As indicated in the drawings, the unit is 11 of the known type in which molten thermoplastic Material through a screw (not shown) from a pipe 12 via a non-return valve (not shown) is conveyed into a chamber 13 in which there is a piston, not shown, which, as seen in FIG Fig. 1, through the thermoplastic material is moved to the right until a certain amount in the chamber for Injection, as a metered amount, through a pipe 14 is contained in the injection mold.

The turret head 1 is equipped with a turret slide 15 (Fig. 5) movable on guide rods 16 to the back and reciprocating along the center line 6 is mounted about a core U or 5 in and out of cooperation to move with the injection mold 7. Figures 2 and U show the position of the turret 1 when the cores 5 cooperate with the injection mold 7, while the cores U, which carry parisons, interact with the blow mold 10. In this position the turret head runs the axis of rotation of the latter through the overlap of planes showing the center line 6 and a center line

309829/0890

contained, which through the surfaces of the blow molds 9, 10 run. These planes are at right angles to each other. Slide 15 is through a flexible coupling 18 coupled to a tendon 19, which also supported by the guide rods 16 and with the piston 20 of a known form of electromechanical actuation unit 21 is connected, which is mounted on the frame F is arranged. The clamping member 19 has a concave surface 22 which is directed to the axis of rotation of the turret head 1 and is concentric with a complementary convex surface 23 which defines surfaces 2, 3 of the turret connects. During a molding cycle when the cores U, 5 with the injection mold and one of the blow molds 9, 10 cooperate, the surfaces 22, 23 rest against one another, around the revoier in a cooperating position to hold with the mold 7. The load that is exerted by the piston 20 can be of the order of magnitude of 250 tons. After the shaping processes, the active blow mold is released from the turret 1 moved away along with the articles blown in the mold, whereupon the piston 20 moves to the left, as seen in Fig. 2 and 4, moved into a position in which the Cores that carry the parisons formed in the injection mold 7 are completely withdrawn from the injection mold and be spaced therefrom as shown in FIG. Before the piston 20 reaches the end of its stroke, the tendon is thereby moved far enough away from the turret head to allow its rotation without hindrance to enable the tendon. There is now a rotary movement of the turret head 1 through an angle of 90 ° by hydraulic or pneumatic working cylinders 24, 25 (Fig. Ό instead, whose piston rods 26, 27 are connected to a two-armed lever 28, which is driven by the turret

- 7 -

309829/0890

42 117 β

head is carried in such a way that during the rotation of the turret head the one piston rod a "thrust" exercises while the other exercises a "pull", as can be seen from FIG.

The blow molds 9, 10 are equipped with blow molding slides 28, 29 movable, which is independent in and out of cooperation with a core 4 or 5, each in Alignment is located, are reciprocable. The carriages 28, 2 9 are in the longitudinal direction of sliding guides 30, 31 slidable by hydraulic or pneumatic working cylinders 32, 33, which are operated with levers 132, 133 (Fig. 2) are connected. Working cylinder 34, 35, which at one end 3ß, 37 (Fig. 3) on the frame F are hinged, and at their opposite ends to the upper ends of mold support plates 38,39 are connected, as shown in Fig. 7, serve to perform two functions, of which the the first consists in keeping the blow molds in a sealing position with respect to the plates P, and the second therein, the blow molds after they have been withdrawn from the molding position towards the plates P, to rotate to a position in which the open ends of the molds are directed downward so that the moldings can be ejected from the molds onto a conveyor (not shown) through which the moldings can be carried away in an orderly manner. For this purpose, the mold carrier plates 38, 39 are on pins 40 stored, and mechanically loaded by springs 41 (Fig. 4), which are located in housings 4 2, which at

43 (Fig. 7) are articulated to the lower ends of the plates 38, 39 and are articulated at 44 to the carriage 28, 29.

VJälu'end a blow molding process; becomes pressurized gas, usually

- ίί -

309829/0890

42 117

Compressed air, into the mold through the cores and the turret introduced by means of a hose 45 which is connected to a compressor or the like 46 (FIG. 2). As usual, it is also desirable to keep the cores in a warm state, which is done by doing this can that heated oil or water is passed around the cores, the heated liquid through a Pump 47 and a hose 48 is supplied, while cooling water through to cool the collar part 49 of the cores a pump 50 and a hose 51 is circulated around it. Neither of these traits forms however part of the invention, so that they are not described in detail here.

However, it has been sometimes found that it is difficult to remove parisons from injection molds, without the parcels being displaced with respect to the cores. To avoid this difficulty it is suggested that prior to moving the cores out of the Injection mold to apply a negative pressure to the cores in order to keep the parisons adhering to them. This can done in that negative pressure from a vacuum pump 5 2 to the cores via a hose 5 3 and the turret head 1 is granted access to the purpose for which the channels in the cores are used, which is described below serve to direct compressed air into the parisons for blow molding.

When the blow molds are not split dies, it is sometimes difficult to blow-molded articles from the cores to be removed, so that it is proposed voi ^"1 loosening a blow mold by its associated cores a negative pressure to the interior of the blow mold are effectively let nodaii the items

3 0 9 8 2 o / o 8 9 0

U2 117

adhere to the interior of the mold and can be easily removed from the cores. This can be done by that the vacuum pump with the blow molds, for example by hoses 54, are connected. The negative pressure is released so that the objects can be ejected from the mold, which ejection in any can be done in a suitable manner known per se.

In the following description of the mode of operation in forming in connection with Figs. 8-28 it is assumed that that each plate P carries only a single core, and that each blow mold has only a single mold cavity and is a split mold.

A complete working cycle, during which ^ two Parcel 8 are molded by injection molding and blow molding, for example, takes 6 seconds and is shown in Fig. 8-28, with Fig. 8 showing the zero time represents at which the injection of one parison is started, one during the previous one Injection molding cycle, injected parison is in position for blow molding is located in the blow mold 9 and the blow mold 9 is closed and begins to become parison move. At this point, an object in the blow mold 10, which is still closed, is cooled and starts the mold 10 will open.

After 0.3 seconds (Fig. 9) the parison continues to spray, the blow mold 9 has been moved into contact with the plate P (not shown) carried by the turret 1 in readiness for blow molding the parison which is now inside the blow mold 9 is located. The blow mold 10 is fully open, so that the blown in this = ¹ .

- 10 -

309829 / 089Ü

ι »2 117

Object is expelled from it.

After 0.6 seconds (Fig. 10) the spraying of the parison is finished, compressed air is admitted to the To begin expanding the parison in the blow mold 9, and the blow mold 10 is in the fully open and fully retracted positions.

After 1.0 seconds (FIG. 11), blowing is continued in the blow mold 9, the parison in the injection mold 7 cooled and the blow mold 10 remains fully open in its fully retracted position.

After 1.5 seconds (FIG. 12), the blowing in the blow mold 9 has ended and the cooling of the object begins in FIG this and the blow mold 9 begins to move into its retracted position. The parison in the injection mold is still being cooled and the blow mold 10 remains fully open in its fully retracted position.

After 1.8 seconds (Fig. 13) the cooling of the parison in the injection mold is finished, the molded article becomes cooled in the blow mold 9 and the mold is fully withdrawn, the blow mold 10 remains fully open in its fully retracted position and the turret 1 and the clamping member 19 begin to move to the left, to remove the parison from the injection mold.

After 2.0 seconds (Fig. 14) the object is still cooled in the blow mold 9 and is located Form in its' closed, fully retracted position, the blow mold 10 is still fully open and in their fully retracted position, the turret 1 and clamping member 19 are still moving

- 11 -

309829/0890

117

on the left, however, the parison has been withdrawn from the injection mold and the turret begins to rotate clockwise.

After 2.4 seconds (Fig. 15) the article is in the blow mold in the closed and fully retracted position Mold 9 is still cooled, the blow mold 10 begins, which is still fully open and fully withdrawn is to close and the turret 1, which is still rotating clockwise, begins to move move right.

After 2.7 seconds (Fig. 16) the object in the blow mold 9 is still closed, fully withdrawn Form 9 cooled, the BlacformlO closes and the turret head 1 is still turning Clockwise and still moving to the right.

After 2.8 seconds (FIG. 17) the article in the blow mold 9 is still in the closed, fully retracted position When mold 9 is cooled, the blow mold 10 will still close while the turret is rotating has finished but is still moving to the right.

After 3.0 seconds (Fig. 18) the article in the blow mold 9 is still in the closed, fully retracted position When the mold 9 is cooled, the blow mold 10 is closed and it begins to move towards the turret head 1 move, which the latter is again in the working position for the injection mold 7, and the injection process begins with parison carried by the core 5 which is in alignment with the closed blow mold 10.

After 3.3 seconds (FIG. 19) the blow mold 9 opens

- 12 -

309829/0890

¹¹² "' a

and she throws out the molded object, that becomes Syringes in the syringe »Form 7 continued» is located the blow mold IQ in the work station on the platform P (not shown), which carries the core 5 and the parison and receives compressed air access »to expand the now in the blow mold 10 contained parison to begin.

After 3.6 seconds (FIG. 20) the blow mold 9 is fully open and fully withdrawn, blowing continues in blow mold 10 and the injection process is in the mold completed.

After 1.0 seconds (FIG. 21) the blow mold 9 is fully open and fully withdrawn, blowing into the Blow mold 10 continues and the parison is in the Injection mold 7 is further cooled.

After _"t i to 5 seconds (Fig. 22) the spout is withdrawn form 9 fully open and fully, the blowing is completed in the blow mold 10, the latter begins to retract and the Külbal is further cooled in the injection mold 7.

After about 8 seconds (FIG. 23) the blow mold 9 is fully open and fully withdrawn, the blow mold 10 is fully withdrawn and is in this on its shape The blown object is cooled and the cooling of the parison in the injection mold 7 is finished.

After 5.0 seconds (FIG. 24) the blow mold 9 is full open and fully withdrawn, the blow mold 10 fully withdrawn and becomes the object in it cooled. If the turret head 1 and the clamping member 19 move to the left, the parison is out of the

- 13 -

$ 309829/089

11? ~

Injection mold 7 is withdrawn and the turret begins to rotate counter-clockwise.

After 5, ¹ * seconds (Fig. 2S) the blow mold 9 fully open and fully retracted "is the blow mold 1 0 fully retracted * and the article contained in it is cooled inoaer still, the turret 1 has started to move to the right and it is still in a counter-clockwise rotation.

After 5.7 seconds (Fig. 26) the blow mold begins 9 to close, the blow mold 10 is fully withdrawn and becomes the object located in it still cooled, the turret head 1 is still leading one movement to the right and one rotation movement in the counter-clockwise direction.

After 5.8 seconds (FIG. 27) the blow mold is still closing, the blow mold 10 is fully withdrawn and if the object contained in the latter is still being cooled, the rotation of the turret is has come to a standstill 'while its movement to the right continues.

After 6.0 seconds (Eg. 28) the blow mold 9 is located in alignment with the parison carried by the core 4 and it begins to move towards the turret: to move, is the plate P (not shown), which carries the core 5, fully in contact with the injection mold 7, the injection process begins and the blow mold 10 begins to open.

By molding articles with the apparatus described above, the output is compared

309829/0890

H2 117 _f g

significantly increased to that of the previously known injection molding / blow molding machines, and it is also possible to use the machine only for one injection process, the rotary movement of the turret head 1 being used for this purpose will achieve the advantage of obtaining longer items with a fixed stroke machine (i.e. an object that is longer than a conventional one Injection molding machine is possible because of the ejection & play). The actuator of the blow molds can then be used for peeling or other auxiliary operations.

- 15 -

309829/0890

Claims (2)

Claims Device for molding thermoplastic objects Material »with plates, one of which is rotatable with each of two faces Turret is connected and from each of which at least one core protrudes and with spray and Blow molds that can work together with the turret head at the same time, so that while a parison is injected around the core protruding from the one plate, one in the preceding injection process parison obtained in the blow mold during a blow molding process is subjected, characterized in that the surfaces (2, 3) of the rotatable turret head (1) are at right angles to each other and parallel to the axis of rotation, the injection mold (7) is stationary and is arranged on a center line (6), an actuating device (20) (21) is provided, which is used to move the turret head (1) along the center line (6) of the injection mold into and out of the shaping position to move the injection mold (7), a turret rotating device (24-28) is provided, by which during alternating periods during which the turret head (1) is withdrawn from the shaping position to the injection mold (7), the Turret head (1) by 90 ° in one direction during one period and in the opposite direction - · 16 - 309829/0890 rotated during the next period »two Blow molds (9, 10) are aligned with each other and have a common center line (17) leading to the The center line (6) of the injection mold (7) is right-angled and runs through the axis of rotation of the turret head (1), when a plate (P) of the turret head is is in the Forragebungsstellung to the injection mold (7), and that by a blow molding movement device (28-33) and (132, 133) the blow molds (9,10) alternately along the mentioned common center line (17) in the blow molding position to the turret head can be moved when the latter is in the forming position for the injection mold. 2. Device according to claim 1, characterized in that that the turret head (1) is movable with a turret head slide (15) which is used for kin and forward movement Guide rods (16) is mounted and the actuating device is an axially reciprocating piston (20), which is connected to a tensioning member (19), which for reciprocating movement on the mentioned Guide rods is stored, and is used to To hold the turret (1) for the shaping position for the injection mold (7), and a flexible coupling (16) Connects the turret slide (15) to the clamping member (19) and in the retracted position of the turret head (1) with respect to the injection mold (7), a rotation of the turret head without obstruction by the tendon (19). - 17 - 309329/0830 117 3 * device according to claim 2, characterized in ±, that the mentioned two surfaces (2, 3) of the turret head (1) by a convex surface (23 *), which is concentric to the axis of rotation of the turret head (1) »are connected, and the tendon (19> is provided with a concave surface (22) which is complementary to the aforementioned convex surface (23). Device according to Claims 1-3, characterized in that that a vacuum generator (5 2, 5 3) is connected to the turret head (1) and in one Core or in cores (4, 5) in the shaping position with respect to the injection mold (7) a negative pressure generated before the turret (1) is withdrawn from the shaping position to the injection mold (7), to remove a shaped parison or shaped parison (8) from the injection mold (7) together with the Core or the cores around which the parison or parisons has been molded in the injection mold, or are to facilitate. 5 »Device according to claims 1-4, characterized in that that a negative pressure generator (52, 5H) is connected to the interior of each of the blow molds (9, 10) is to create a negative pressure inside a mold before it comes out of the molding position the turret is withdrawn so that an object or objects are molded in the blow mold has been or are, adheres or adhere to the inside of the blow mold, so that the object or - 18 309829/0890 »2 117 the objects are removed together with the blow mold from the shaping position relative to the turret head or become. *. Device according to claims 1-5, characterized in that each blow mold (9, 10) of one Plate (38, 39) is carried on a blow molding slide (28, 29) is pivotably mounted, which can be moved back and forth along guides (30, 31) is, and that at least one elongated working cylinder (33, 3H) at one end (36, 37) is articulated to a stationary part (F) and at the opposite end to the mentioned plate (38, 39), which or which working cylinder (33, 34) can be actuated in the shaping position of the blow mold or are to keep the latter in a sealed blow molding position to the turret head and in the retracted Position the blow mold to rotate the plate (38, 39) around its pivot (HO) into a position in which the open end (s) the blow mold downward to eject a blow molded article (s) is directed from the blow mold or are. - 19 -309829/0890