DE19737697A1 - Blow molding of plastics bottles in two or more rotating injection molding tables - Google Patents

Abstract

Each rotating injection molding table (6, 8) has multiple cavities and all pre-forms (34) are removed initially from the first molding table (6) and then all from the other (8) by a rotating movement of a transfer unit (18) which subsequently transfers them to a blowing unit (22) for inflation into bottles. An Independent claim is also included for a bottle production plant.

Description

The invention relates to a method for producing Hollow bodies made of plastic, in particular plastic bottles, according to the preamble of claim 1 and one Device for the production of hollow plastic bodies, especially plastic bottles, according to the preamble of Claim 2.

In the production of hollow plastic bodies, e.g. B. PET Bottles are first made using an injection mold Plastic blanks produced. As a rule, such are Plastic blanks cylindrical, closed at one end Hollow body that is heated in the injection mold Plastic are formed from an extruder in the Molds is injected. Be in a blow molding facility  the plastic blanks then to the final dimension of the Plastic container stretched and inflated.

A generic device for the production of Hollow plastic bodies are described in DE 195 28 695 A1. Takes a transport device in the form of a turntable injection molded plastic blanks from an injection mold and leads this by rotation to a temperature control station, in which the blanks on the necessary for blow molding Temperature. By another rotation the plastic blanks are brought to a blowing station, in which they are stretched and inflated.

After injecting the heated plastic into the Injection molds require the plastic for a period of time cool down before the plastic blanks come out of the injection mold be removed. The spraying process together with the The cooling process generally takes about twice the time like the blowing process for inflating the plastic blanks. The throughput is therefore essential due to the length of time determined for spraying or cooling the blank is needed. To compensate for this time difference are in the generic device two Injection molding devices are provided. While in one Injection molding equipment a variety of Plastic blanks is injected at the same time and the molded plastic blanks can cool down finished plastic blanks from each other Injection molding device to the blow molding device passed on. The plastic blanks that are in an injection molding process simultaneously, too simultaneously passed on to the blow molding device. On this creates a discontinuous, clocked Operation which necessarily leads to the fact that  Blow molding device runs discontinuously. This then leads inevitably also to discontinuous emissions of manufacture plastic hollow bodies and to limit the Power. In particular, a direct connection to a subsequent treatment station that is continuous works, e.g. B. a filler of a beverage filling system, not possible.

An arrangement similar to the generic device is also disclosed in EP 0334 483 A2.

Based on the object of the present invention state of the art, a device for the production of hollow plastic bodies, in particular Plastic bottles, and a corresponding process too to provide their manufacture, in which the produced hollow body immediately to a continuous working treatment station can be handed over.

This task is accomplished by a generic method the features of the characterizing part of claim 1 and by a generic device with the features of characterizing part of claim 2 solved.

In the method according to the invention, the Plastic blanks alternating from one Injection mold rotor that is rotatable in one Rotation movement individually and continuously from the Transfer facility taken over and to the Hand over blow molding device.

For this purpose, in the device according to the invention Injection molding devices designed as rotors and the Transfer device includes a continuously rotating  Transfer rotor with facilities for taking over individual Plastic blanks from one of the injection molding rotors and for individually dispensing the plastic blanks to the Blow molding device. Furthermore, the invention Device on a first switching mechanism that the Transfer device from an operating state in which it Plastic blanks from the first injection molding rotor, switches to an operating state in which it Plastic blanks from the second injection mold rotor takes over, or vice versa.

In the method according to the invention, the Plastic blanks of an injection mold rotor from the Transfer facility taken over while in the Injection mold nests of the other injection mold rotor heated plastic, e.g. B. fed from an extruder becomes. The injection molding devices are as a rotor trained so that of the also as a rotor trained transfer device the plastic blanks in a rotation can be removed individually.

While the blanks in an injection mold rotor be injection molded, with this rotor standing, gives the other rotor the cooling blanks to the Transfer rotor continues, which then transfers these blanks to the Blow molding device passes. After the complete delivery the plastic blanks from an injection mold rotor its drive is shut down and new blanks are in it injection molded and cool. At the same time, the previous step in the second injection mold rotor formed plastic blanks to the transfer rotor in one continuous rotary motion. So it will intermittently always one of the two rotors for delivery driven by blanks to the transfer rotor, so that the  Transfer rotor continuously and without gaps individual blanks Deliver to the continuously working blow molding device can. This blow molding device can then be finished Plastic hollow body continuously z. B. a fountain pen pass on. So there is a continuous operation, which makes the production of the hollow plastic body better in the remaining production and treatment steps, e.g. B. in a bottling line, inserts and the throughput is increased.

According to an advantageous development of the device according to the invention is a second Switching device for switching the supply of heated Plastic provided on the injection mold rotor that immediately before the transfer device completely has been emptied. This second switching mechanism works in sync with the first Switching mechanism that always the injection mold rotor is supplied with heated plastic that is not currently from the transfer device is emptied.

In an advantageous embodiment of the invention Device includes the transfer rotor controlled Gripping elements to make plastic blanks from one Injection mold rotor to take over and to the Pass blow molding device. The gripping elements are controlled so that they are emptied from the Injection mold rotor plastic blanks can take over pass them on to the blow molding device.

For the control of the gripping elements, e.g. B. individual Drives can be provided on an electrical signal react, or corresponding pneumatic cylinder. According to one  advantageous embodiment is a backdrop intended.

According to this embodiment, the invention comprises Device a first backdrop in a cover plate of the Transfer rotors and a second backdrop in a base plate of the transfer rotor, and comprise the gripping elements Guide elements from the first switching mechanism to Intervention in the first or the second setting switched can be. The first backdrop controls the Guide elements so that the corresponding gripping elements the plastic blanks only from the first injection mold rotor take over the leadership elements while the second backdrop controls so that the gripping elements only the plastic blanks take over from the second injection molding rotor. Such Set control enables a simple and robust Construction that works with high reliability.

In an advantageous embodiment of the backdrop guide The device according to the invention comprises each gripping element controlled displacement element with a gripping device, on the area of the respective displacement element is arranged by the axis of the transfer rotor is removed. Such a sliding element is used to Transfer or delivery process of the plastic blanks in the To carry out gripping devices. The sliding elements can z. B. moved by pneumatic cylinders. However, is advantageous for the displacement elements a guided tour provided. The sliding elements intervene in a third or fourth setting, the Move sliding elements so that the distance of the Gripping devices from the axis of the transfer rotor itself then changed if one of the respective gripping element Plastic blank is taken over or delivered.  

In an advantageous embodiment, the Gripping devices spring-loaded clamps. This Brackets are moved and moved by the sliding elements hold the plastic blanks by spring force. A such a clamp mechanism is simple and inexpensive.

The gripping elements can be controlled so that they can a pivoting movement in the transfer area of the respective Injection mold rotor or the delivery area to the Blow molding device arrive. Such a swivel movement can be easily realized with L-shaped gripping elements, which at its corner point can be pivoted with the transfer rotor are connected, the guide element on one arm is arranged to engage in the first or second backdrop and on the other arm the sliding element. By rotating the Transfer rotor moves the guide element in the first or second backdrop and pivots the gripping element.

Each of the injection mold rotors can be of its own Extruder are fed. Easily, too both injection mold rotors fed by an extruder by the second switching mechanism for feeding of the other injection mold rotor can be switched.

The blow molding device is designed so that it Plastic blanks continuously from the transfer rotor can take over. This can e.g. B. by a circumferential Weight loss happen. Advantageously, the Blow molding device a continuously rotating blowing wheel with recordings arranged on its circumference for Plastic blanks. Such a blowing wheel enables simple way of continuous operation and is of simple structure.  

The plastic blanks can e.g. B. in the Blow molding device also on the necessary for inflation Temperature. It is also conceivable that the from the injection molding process still warm plastic blanks from one Injection mold rotor so quickly brought to the blowing station be that they still have sufficient heat that they can be inflated. According to one embodiment is however one in the area of the transfer device Temperature control device provided that the plastic blanks on their way from the injection mold rotor to Blow molding device holds at a desired temperature. Depending on the requirement and the special structure, it is a cooling device (e.g. a fan or airflow cooling) or a heater, e.g. Legs Infrared heating.

In the following, an embodiment is based on the figures the inventive device and an embodiment of the described method according to the invention.

It shows

Fig. 1 shows a schematic top view of an inventive apparatus for producing plastic hollow bodies,

Fig. 2 is a schematic detailed view of the transfer star area and

Fig. 3 is a schematic detailed view of the same area in a different operating state.

As shown in FIG. 1, the inventive apparatus comprises an extruder 2 for supplying heated plastic under pressure. The extruder 2 opens into a control valve 4 for controlling the heated plastic flow either to the first injection mold rotor 6 or to the second injection mold rotor 8 . Motors 14 and 16 serve to drive the injection mold rotors. Arrows 36 and 38 indicate the direction of rotation of the injection mold rotors 6 and 8 . Channels 10 for distributing the heated plastic are provided within the injection mold rotors 6 , 8 . These channels 10 are connected via a rotary distributor 12 to the plastic feed from the extruder 2 .

18 denotes a transfer rotor which is driven by a motor 20 . The direction of rotation is indicated by arrow 40 . 34 denotes an example of a plastic blank in the transfer rotor 18 .

The blowing wheel 22 is driven by the motor 24 . The direction of rotation is indicated by arrow 42 . Blow molds 26 are arranged on the circumference of the blowing wheel 22 . Following the blowing wheel 22 follows an outlet star 28 , which is driven by a motor 30 in the direction of arrow 44 and takes over the finished bottles 32 from the blowing wheel 22 and feeds further treatments.

In Fig. 1, the injection mold rotors 6, 8 shown with eight injection mold nests 70th Any other number is also possible. It is e.g. B. in a known manner divisible injection molds that can be opened to remove the injection molded parts.

In Fig. 2 is a detail view of a device according to the invention is shown, in which the transfer rotor 18 plastic blanks 34 takes over from the first injection mold rotor 6. The same elements as in Fig. 1 are given the same reference numerals. In the embodiment shown, the axes of the first injection mold rotor 6 , the transfer rotor 18 and the second injection mold rotor 8 are arranged at a 90 ° angle 46 . 48 shows an L-shaped gripping element which is articulated on a pivot axis 54 at its corner point. The gripping element 48 in each case comprises a guide element 50 in the form of a rotatable cam roller which runs in a first or second link 56 or 58 and a displacement element 52 which runs in a third or fourth link 60 or 62 . These scenes can be realized in the stationary ceiling or floor plate of the transfer rotor 18 . At the outer end of the displacement elements 52 there are gripping devices 64 , which in the present example are designed as spring-loaded clips. The injection mold nests of the injection mold rotor 6 are indicated at 66 .

FIG. 3 shows the same area as in FIG. 2, only that the transfer rotor 18 is shown in an operating state in which it takes over plastic blanks 34 from the second injection molding device 8 . Both in FIG. 2 and in FIG. 3, the injection mold nests 66 of the second injection mold rotor 8 are not shown explicitly, but are symbolized by lines.

The following is the operation of an inventive Device for injection blow molding of hollow plastic bodies explained.  

Heated, flowable plastic is pressed by the extruder 2 under pressure through a nozzle into the control valve 4 . This control valve 4 is, for. B. set so that the injection mold rotor 8 is supplied with plastic. The heated plastic is pressed into the individual injection mold nests 70 through channels 10 . The injection mold rotor 8 does not rotate. The individual channels 10 are supplied with heated plastic via a rotary distributor 12 .

During the injection molding process in the injection molding rotor 8 , cooled plastic blanks 34 are removed from the first injection molding rotor 6 (as shown in FIG. 2), the molds of which have been opened for this purpose in a manner known per se. The removal by the transfer rotor 18 is done by controlling the gripping elements 48 in such a way that they take over the plastic blanks 34 from the first injection molding rotor 6 with clamps 64 . The movement of the gripping elements 48 is controlled via scenes. The respective guide element 50 of a gripping element 48 is guided by a link 56 while the transfer rotor 18 is rotated. This triggers a pivoting movement of the gripping element 48 . This pivoting movement ensures that while the transfer rotor 18 takes over plastic blanks from the first injection mold rotor 6 , the L-shaped gripping elements 48 are pivoted in the region of the second injection mold rotor 8 such that they do not engage in the orbit of the second injection mold rotor 8 . Sliding elements 52 of each gripping element 48 run in a further setting 60 . At the transfer point from the injection mold rotor 6 to the transfer rotor 18 , this link has such a shape that the displacement element is moved radially outwards when the transfer rotor 18 rotates. The gripping clip 64 is pushed over a plastic blank 34 with elastic expansion. This is then removed from the injection mold rotor 6 . Both the transfer rotor 18 and the injection mold rotor 6 rotate continuously and are coordinated in speed so that the plastic blanks 34 are continuously removed. The transfer rotor 18 transports the plastic blank 34 in the gripping bracket 64 of a gripping element 48 to the continuously rotating blowing wheel 22 . At the transfer point to the blowing wheel 22 , a blow mold 26 takes over the plastic blank from the transfer rotor 18 . This can e.g. B. happen by an opening and closing split shape with a blow mandrel, which is also controlled with the help of scenes or pneumatics. For this purpose, the brackets 64 on the displacement elements 52 are guided outward through the link 60 by the first injection molding rotor 6 , similarly as at the transfer point, and then drawn in. In the further circulation, the preformed plastic blanks 34 are then inflated to their final dimensions and stretched. The bottles 32 formed in this way are transferred from the blowing wheel 22 to a continuously rotating outlet star 28 which, for. B. may have the same backdrop-guided gripping elements 68 as the transfer rotor 18th The finished bottles 32 are then from the outlet star 28 to a further continuously operating treatment station, for. B. passed a fountain pen.

After the plastic blanks 34 are discharged from the injection mold rotors 6 , 8 in a highly heated state, less additional heat is required for the blowing process to heat the blanks to the temperature required for the blowing process than if the blanks are allowed to cool after the injection molding. 34 to the blow molding process to temper the temperature of the plastic blanks so that these have suitable for the blow molding temperature, a temperature control, not shown may be between the injection mold rotors 6, 8 in the region of the transfer rotor 18 can be arranged which either heats or cools, at least affects the blanks in the direction of the temperature required for the blowing process.

When the first injection mold rotor 6 is completely emptied, the gripping elements 48 are z. B. switched by an axial displacement of the cam rollers so that their guide elements 50 engage in the link 58 , 62 , through which they are controlled so that they can accept blanks from the injection mold rotor 8 , and on the other hand no longer in the orbit of the injection mold rotor 6 intervention.

This state is shown in Fig. 3. Through the guide 58 , 62 when the transfer rotor 18 rotates, the gripping elements 48 are pivoted about their pivot axis 54 in such a way that they are not hindered by the latter in the area of the injection mold rotor 6 . On the other hand, however, the gripping clips 64 are guided into the orbit of the continuously rotating injection mold rotor 8 so that blanks can now be taken over from there. The guidance of the displacement elements 52 in the fourth link 62 leads to the displacement elements 52 moving radially outward in the transfer area of the injection molding device 8 and pushing the gripping clips 64 over the plastic blanks 34 of the second injection mold rotor 8 . As a result, these are removed from the second injection mold rotor 8 and fed from the transfer rotor 18 to the blowing wheel 22 , as has already been described above for the plastic blanks 34 which have been taken over by the first injection mold rotor 6 . Both the transfer rotor 18 and the second injection mold 8 rotate at a speed such that a continuous transfer from the injection mold rotor 8 to the transfer rotor 18 is ensured.

While the plastic blanks 34 are taken over by the continuously rotating second injection mold rotor 8 , the first injection mold rotor 6 stands and is supplied with heated plastic from the extruder 2 . For this purpose, the control valve 4 of the extruder 2 is switched from the injection mold rotor 8 to the injection mold rotor 6 simultaneously with the switching process of the guide elements 50 and the displacement elements 52 . In this way it is ensured that new plastic blanks 34 are formed in the injection mold rotor 6 , while on the other hand plastic blanks 34 are taken over by the injection mold rotor 8 .

If the plastic blanks 34 are then completely removed from the injection mold rotor 8 , the switching process of the guide elements 50 , the displacement elements 52 and the control valve 4 is carried out in reverse in order to exchange the tasks of the two injection mold rotors 6 , 8 again.

With the device according to the invention is a continuous transfer of plastic blanks from the Injection molding device to the blow molding device guaranteed. In this way, the performance of the Increase injection blow molding machine overall and it can integrate more easily into a work place in which continuous processes prevail.

Claims (12)

1. A process for the production of hollow bodies made of plastic, in particular plastic bottles, in which plastic blanks are formed in at least two separate injection mold devices, each with a large number of injection mold nests, then transferred from a transfer device from the injection mold devices to a blow molding device and inflated there by excess pressure, characterized in that that rotatable injection mold rotors ( 6 , 8 ) are provided as injection molding devices and that first all plastic blanks ( 34 ) from an injection mold rotor ( 6 ) and then all plastic blanks ( 34 ) from another injection mold rotor ( 8 ), always alternating, continuously and individually in a rotational movement transferred from the transfer device ( 18 ) and transferred to the blow molding device ( 22 ). 2. Device for the production of hollow plastic bodies, in particular plastic bottles, with at least one extruder, two injection mold devices, each with a plurality of injection mold nests, which are fed by the at least one extruder with heated plastic for molding plastic blanks, and with a transfer device for transferring the plastic blanks from the injection molding devices to a blow molding device for expanding the plastic blanks, characterized in that each injection molding device is designed as a rotor ( 6 , 8 ), the transfer device is a continuously rotating transfer rotor ( 18 ) with devices ( 48 ) for taking over individual plastic blanks ( 34 ) from one of each Injection mold rotors ( 6 , 8 ) and for individually releasing the plastic blanks ( 34 ) to the blow molding device ( 22 ) and that the transfer rotor ( 18 ) from an operating state in which it blanks plastic from the e rsten injection mold rotor ( 6 ) takes over, can be switched into an operating state in which it accepts plastic blanks ( 34 ) from the second injection mold rotor ( 8 ), or vice versa. 3. Apparatus according to claim 2, characterized by a switching mechanism ( 4 ) for switching the supply of heated plastic to that injection mold rotor ( 6 , 8 ) which has been completely emptied immediately before by the transfer rotor ( 18 ). 4. Device according to one of claims 2 and 3, characterized in that the transfer rotor ( 18 ) comprises controlled gripping elements ( 48 ) to accept plastic blanks ( 34 ) from an injection mold rotor ( 6 , 8 ). 5. The device according to claim 4, characterized by a first fixed link ( 56 ) and a second fixed link ( 58 ) for controlling the gripping elements ( 48 ), wherein the gripping elements ( 48 ) comprise guide elements ( 50 ) between an engagement in the first link ( 56 ) can be switched into the second link ( 58 ), and the first link ( 56 ) guides the guide elements ( 50 ) so that the corresponding gripping elements ( 48 ) remove the plastic blanks ( 34 ) only from the first injection mold rotor ( 6 ) take over and the second link ( 58 ) guides the guide elements ( 50 ) of the respective gripping elements ( 48 ) such that the gripping elements ( 48 ) take over the plastic blanks ( 34 ) only from the second injection mold rotor ( 8 ). 6. The device according to claim 5, characterized in that each gripping element ( 48 ) comprises a controlled displacement element ( 52 ) with a gripping device ( 64 ) which is arranged on the region of the respective displacement element ( 52 ) which is from the axis of the transfer rotor ( 18 ) is removed. 7. The device according to claim 6, characterized in that the displacement elements ( 52 ) for control can engage in a third ( 60 ) or fourth ( 62 ) link, which move the displacement elements ( 52 ) such that the distance between the gripping devices ( 64 ) The axis of the transfer rotor ( 18 ) changes in particular when a plastic blank ( 34 ) is taken over or delivered by the gripping device ( 64 ). 8. The device according to claim 7, characterized in that the gripping devices are spring-loaded clips ( 64 ). 9. Device according to one of claims 6 to 8, characterized in that the gripping elements ( 48 ) are L-shaped bodies which are pivotally connected at their corner point ( 54 ) to the transfer rotor ( 18 ), the arm (1), the guide element ( 50 ) for engagement in the first ( 56 ) or second link ( 58 ) and on the other arm the displacement element ( 52 ). 10. Device according to one of claims 3 to 9, characterized in that the injection mold rotors ( 6 , 8 ) are fed by only one extruder ( 2 ), the output of which can be switched by the switching mechanism ( 4 ) from one to the other injection mold rotor. 11. Device according to one of claims 2 to 10, characterized in that the blow molding device comprises a continuously rotating blowing wheel ( 22 ) with blow molds ( 26 ) arranged on its circumference. 12. Device according to one of claims 2 to 11, characterized in that a temperature control device is provided in the region of the transfer rotor ( 18 ) which brings the plastic blanks ( 34 ) to a temperature suitable for blow molding.