WO1998021019A1

WO1998021019A1 - Method and device for tranferring castings

Info

Publication number: WO1998021019A1
Application number: PCT/DE1997/002143
Authority: WO
Inventors: Klaus Vogel; Michael Linke; Julian Choinski
Original assignee: Krupp Corpoplast Maschinenbau Gmbh
Priority date: 1996-11-09
Filing date: 1997-09-20
Publication date: 1998-05-22
Also published as: AU4698897A; DE19646365A1

Abstract

The inventive method and device are intended for transferring castings to the area of a blow-forming unit designed to produce thermoplastic containers. A blank is fed to at least one heat producing unit for the purposes of preliminary heating and to at least one blow-forming unit. On at least one section of the path, the blanks are held by a gripping device (33) and the casting (32) positioned by a holding member (23), relative to which a positioning device (24) is fixedly mounted, just as a direction setting device is mounted fixedly relative to the holding member (23). In the case of a relative motion by the gripping member (33) in the direction of the casting (32) to be gripped, the direction setting device (17) is so positioned relative to the positioning member (24) that the gripping member (33) is also positioned relative to the casting (32). The method enables material degradations and rubbing off to be prevented.

Description

Method and device for transferring formations

The invention relates to a method for transferring moldings in the area of a device for blow molding containers made of a thermoplastic material, in which a preform is fed to at least one heating device for temperature control and at least one blow molding station for blow molding, and in which the moldings are carried along at least part of their transport path are held by a gripping element.

The invention further relates to a device for transferring moldings in the area of a device for blow molding containers made of a thermoplastic material, in which the device for blow molding is a heating device for tempering Has preforms and at least one blow molding station for blow molding the preforms and which is provided with at least one gripping element which holds the preforms along at least part of their transport path within the blow molding device.

Devices of this type are used to feed preforms made of a thermoplastic material, for example preforms made of PET (polyethylene terephthalate), to different processing stations within a blow molding machine. Typically, such a blowing machine has a heating device and a blowing device, in the area of which the pre-tempered preform is expanded into a container by biaxial orientation. The expansion takes place with the aid of compressed air which is introduced into the preform to be expanded. The procedural / sequence with such an expansion of the preform is explained in DE-OS 43 40 291. The device can also be used to remove blown containers from the blowing device.

The basic structure of a blow molding station for container forming is described in DE-OS 42 12 583 and possibilities for tempering the preforms are explained in DE-OS 23 52 926.

The preforms and the blown containers can be transported within the blow molding device with the aid of different handling devices. The use of transport mandrels on which the preforms are attached has proven particularly useful. The use of support bodies for handling the preforms has the advantage that the preforms can be attached with their mouths to a coupling element of the support body and that during the further transport movements the transport elements used only act on the support body and not directly on the preform. This prevents damage and deformation of the preform, which is soft due to the heating. In addition, material removal through direct-acting gripping elements, which could lead to dust formation, for example, is avoided.

The known supporting bodies in the form of transport mandrels have a high mechanical strength and, as a result, are highly reliable and have a long service life. In particular when using rotating transport devices, however, centrifugal forces occur which impair the handling speed.

The use of gripping tongs for handling preforms is described, for example, in FR-OS 27 20 679. A spreading mandrel that can be inserted into a mouth area of the preform for holding purposes is explained in WO 95 33 616.

According to the prior art, it is not sufficiently possible to combine the properties of a low weight of the device for handling the moldings, a high level of operational safety and careful handling of the moldings.

The object of the present invention is therefore to provide a device of the type mentioned in the introduction improve that a gentle handling of the moldings is guaranteed with a low building weight.

This object is achieved in that the molded article is positioned by a holding element before the gripping element is accessed, a positioning element is arranged relative to the stationary element, that an alignment element is arranged stationary relative to the gripping element, and that a relative movement of the gripping element in the direction of the to be gripped molding, the alignment element is positioned relative to the positioning element and thus also the gripping element relative to the molding.

Another object of the present invention is to improve a device of the type mentioned in the introduction in such a way that gentle handling of the moldings is supported with a low overall weight of the device.

This object is achieved in that the gripping element is rigidly coupled to an alignment element, that a positioning element is arranged in the region of a holding element carrying the molding, and that the alignment element and the gripping element are adapted relative to one another and arranged relative to one another such that with a relative movement of the gripping element in the direction of the holding elements by contact between the alignment element and the positioning element there is an orientation of the gripping device relative to the molding.

A typical handling process can be carried out in that the gripping element is positioned by a transfer wheel. To facilitate transfer of the molding, it is proposed that the gripping element can be positioned in the radial direction relative to the transfer wheel.

According to a variant of the method it is provided that the holding element is arranged in the area of the blowing station.

It is also possible for the holding element to be arranged in the region of the heating device.

A two-dimensional positioning can be supported by a tapering guide when the alignment element and the positioning element interact, so that positioning is carried out transversely to a direction of movement of the gripping element and by an effective stop, positioning is also carried out in the direction of movement of the gripping element.

To provide a smooth adjustment, it is provided that the positioning element is used in a roll-like manner.

Alignment is supported in that the alignment element is used in a fork-like manner.

According to another embodiment it is provided that the positioning element is used like a fork.

Adapted to this, it is expedient that the alignment element is used in a roll-like manner.

A possible application is that the molding is handled standing with a mouth oriented vertically downwards. In particular, a use of the method is also characterized in that the molding is handled hanging with a mouth oriented vertically upwards.

According to a typical implementation of the container formation, it is provided that the molded article is stretched in the longitudinal direction within the blowing station after a transfer has taken place.

To carry out a biaxial orientation, it is provided that the molded article is expanded and biaxially oriented after it has been transferred within the blowing station from a medium under pressure.

Exemplary embodiments of the invention are shown schematically in the drawing. Show it:

1 is a schematic plan view of a device for blow molding thermoplastic materials,

2 shows a plan view of an alignment element which is arranged above a gripping element which cannot be seen in this viewing direction,

Fig. 3 shows a cross section along section line III-III in Fig. 1 with an associated positioning element

and

Fig. 4 is a schematic representation to illustrate an arrangement of the alignment element in the area of a molding and the assignment of the alignment element to the gripping element.

In the embodiment shown in FIG. 1, the device for blow molding containers has a heating wheel (1) and a blowing wheel (2). Preforms to be processed are fed via a feed rail (3) into the area of a turning device (4) and transported by transfer wheels (5,6,7) into the area of the heating wheel (1). In this variant, the preforms are guided hanging with their mouths oriented upwards along the feed rail (1) and rotated by 180 ° by the turning device (4). Heating in the area of the heating wheel (1) takes place in such a way that the preforms are oriented upright with their mouths facing downward. However, it is also conceivable to carry out a hanging heating without previously turning the preforms.

Heating devices (8) and cooling devices (9) are arranged along the heating wheel (1). A cooling device (9) is preferably arranged between two heating devices (8). The heating devices (8) heat the preforms with the aid of IR radiation and the cooling devices (9) blow air onto the surfaces of the heated preforms for surface cooling.

After heating and passing through a cooling section, the tempered preforms are transported from a transfer wheel (10) to the blowing wheel (2) and used here in molds (11) which are held by blowing stations (12). The blowing stations (12) can be opened and closed like a book. After the blowing process has been completed, the blown containers are removed from the blowing station (12) and from transfer wheels (13,6,14) an output section (15) fed. When the preforms are blow molded in the area of the blowing wheel (2) with a mouth orientation downward, it is particularly intended to arrange a further turning device between the blowing wheel (2) and the discharge section (15), so that the blown containers hang in the area of the discharge section ( 15) can be transported.

Fig. 2 shows a plan view of the transfer wheel (10), which inserts the preforms into the blowing stations (12) in the area of the heating wheel (1). In the associated embodiment, it is in particular contemplated to expand the preforms with their mouths oriented upward in the area of the blowing station (12) to form a finished container. Alignment elements (17) are arranged in the area of transfer arms (16) of the transfer wheel (10) to ensure precise insertion of the preforms into the blow molding station (12). The alignment element (17) has a fork-like centering seat (18).

The transfer arms (16) consist of an arm base (19) rigidly connected to the transfer wheel (10) and a telescopic arm extension (20) which, among other things, carries the alignment element (17). The transfer arms (16) are mounted so as to be rotatable relative to an arm axis of rotation (21) so as to be pivotable. Typically, the rotatable mounting is realized in such a way that there is only a slight play, which makes it possible to perform circumferential evasive movements of approximately +/- 1 mm in the area of the centering receptacle (18). A clearance of +/- 0.5 mm is usually sufficient. In FIG. 2, an assembly aid element (22) is additionally arranged on the essentially horizontal transfer wheel (10), which prevents the arm extension (20) from moving relative to the arm base (19) during assembly. It can also be seen that the centering receptacle (18) widens in a direction facing away from the arm rotation axis (21) in order to support a funnel-like threading.

FIG. 3 shows a cross section along section line III-III in FIG. 2 with the mounting aid element (22) detached relative to the alignment element (17) and with an arm extension (20) retracted in such a way that the alignment element (17th ) approximated to the arm base (19).

In the embodiment according to FIG. 3, a holding element (23) is provided for fixing the molding in the area of the blowing wheel (2). The holding element (23) is not recognizable in Fig. 3 due to its mounting position. A positioning element (24), which is fixedly assigned to the holding element (23), serves to align the alignment element (17) in the event of a relative approach. In the fork-like embodiment of the alignment element (17) according to FIG. 2, the positioning element (24) can be designed, for example, as a roller (25). The role

(25) can be designed, for example, as a rotatable sleeve which is rotatably supported by a stretching rod guide (26). The horizontal bar guide

(26) is used to guide a stretching rod (27) and lead it through a connecting piston (28) to the compressed air line in the area of the molding.

To enable compressed air to be supplied to the molding, the connecting piston (28) has an air supply (30) and various seals (29). Within the Connection piston (28), the compressed air is passed through an annular gap (31) surrounding the stretching rod (27).

FIG. 4 shows the assignment of the components according to FIG. 3 in another image detail, which in particular also clarifies the mounting of the molded part (32). In the processing state shown, the molding (32) is designed as a preform, which has already been tempered for subsequent biaxial orientation, but which has not yet been subjected to compressed air.

The molding (32) is held above the blowing station (12) by a gripping device (33) which is arranged in a stationary manner relative to the alignment element (17). The gripping device (33) is thus positioned by the transfer arm (16) together with the alignment element (17).

For height positioning, the connecting piston (28) is provided with a guide roller (34) which can be positioned by an associated cam control.

The aligning process and thus an indexing is carried out in such a way that, when the gripping device (33) moves together with the molded article (32) in the direction of the holding element (23), the positioning element (24) aligns the aligning element

(17) takes place. Due to the fixed assignment of the alignment element (17) to the gripping device (33) and the positioning element (24) to the holding element (23), the preform is exactly defined on the holding element

(23) handed over. An analogous sequence occurs after the preform has been inflated and oriented to the finished container, which is again released from the blowing station by a comparable gripping device (33)

(12) is removed. Again, for an exact Positioning of the gripping device (33) relative to the molding (32) is provided so that rubbing or grinding of gripping jaws of the gripping device (33) on the material of the molding (32) can be avoided.

The combination of the gripping device (33), the alignment element (17), the holding element (23) and the positioning element (24) can be used in modified embodiments at any point on the blow molding machine at which the molded part (32) is transferred. In particular, it can also be used when the molding (32) is transferred to the heating wheel (1) and when the molding (32) is transferred from the heating wheel (1) to a further transfer device.

In the case of a constructive realization of the alignment element (17) and the positioning element (24), the described realization of the alignment element (17) as a funnel-like fork and of the positioning element (24) as a roller-like part can take place, but it is also possible for the gripping device (33) to be provided with a suitably positioned roller which is inserted into a tapering receiving element assigned to the holding element (23). Other variants of the described direct mechanical alignment of the parts relative to one another are also conceivable, for example non-contact alignment due to magnetic fields acting on them.

Claims

P a t e n t a n s r u c h e

Method for transferring moldings in the area of a device for blow molding containers made of a thermoplastic material, in which a preform is fed to at least one heating device for temperature control and at least one blow molding station for blow molding, and in which the moldings are held by at least part of their transport path by a gripping element characterized in that the molded article (32) is positioned before the gripping element (33) is accessed by a holding element (23), a positioning element (24) is arranged relative to the stationary one, and an alignment element is fixed relative to the gripping element (33) (17) is arranged and that when the gripping element (33) moves relative to the molded article (32) to be gripped, the alignment element (17) is positioned relative to the positioning element (24) and thus also the gripping element (33) relative to the molded article (32).

2. The method according to claim 1, characterized in that the gripping element (33) from a transfer wheel

(5,6,7,13,17) is positioned.

3. The method according to claim 1 or 2, characterized in that the gripping element (33) is positioned relative to the transfer wheel (5,6,7,13,14) in the radial direction.

4. The method according to any one of claims 1 to 3, characterized in that the holding element (23) is arranged in the region of the blowing station (12).

5. The method according to any one of claims 1 to 3, characterized in that the holding element (23) is arranged in the region of the heating device (8).

6. The method according to any one of claims 1 to 5, characterized in that positioning is carried out transversely to a direction of movement of the gripping element (33) by a tapered guide in cooperation of the alignment element (17) and the positioning element (24) and that When the stop becomes effective, the positioning of the gripping element (33) is also positioned.

7. The method according to any one of claims 1 to 6, characterized in that the positioning element (24) is used in a roll-like manner.

8. The method according to any one of claims 1 to 7, characterized in that the alignment element (17) is used like a fork.

9. The method according to any one of claims 1 to 6, characterized in that the positioning element (24) is used like a fork.

10. The method according to any one of claims 1 to 6, characterized in that the alignment element (17) is used in a roll-like manner.

11. The method according to any one of claims 1 to 10, characterized in that the molding (32) is handled standing with a mouth oriented vertically downwards.

12. The method according to any one of claims 1 to 10, characterized in that the molding (32) is handled hanging with a mouth oriented vertically upwards.

13. The method according to any one of claims 1 to 12, characterized in that the molding (32) is stretched in the longitudinal direction within the blowing station (12) after a transfer from a stretching rod (27).

14. The method according to any one of claims 1 to 13, characterized in that the molding (32) after a transfer within the blowing station (12) expanded from a medium under pressure and oriented biaxially.

15. Device for transferring moldings in the area of a device for blow molding containers made of a thermoplastic material, in which the device for blow molding has a heating device for tempering preforms and at least one blow molding station for blow molding the preforms and which is provided with at least one gripping element, which holds the molded articles along at least part of their transport path within the blow molding device, characterized in that the gripping element (33) is rigidly coupled to an aligning element (17) that in the region of a holding element (23) carrying the molded article (32) Positioning element (24) is arranged and that the alignment element (17) and the gripping element (33) are designed so as to be adapted relative to one another and are arranged relative to one another in such a way that when the gripping element (33) moves relative to the holding element (23) by contact between the alignment element (17) and the positioning element (24) an orientation of the gripping element (33) relative to the molding (32) is predetermined.

16. The apparatus according to claim 15, characterized in that the pull-out element (17) is designed as an expanding fork and the positioning element (24) as a roller.

17. The apparatus according to claim 15, characterized in that the alignment element (17) is designed as a roller-like element and the positioning element (24) as an expanding fork. 16 -

18. Device according to one of claims 15 to 17, characterized in that the gripping element (33) is coupled to a stop for limiting a movement path.

19. Device according to one of claims 15 to 17, characterized in that in the region of an engagement of the alignment element (17) in the positioning element (24) a decreasing play is provided for carrying out a constant alignment.