Blow-moulding device with preloadable attachment for blow moulds

Abstract

A transforming device for transforming plastic preforms into plastic containers, comprising a blow-molding device which forms a cavity inside which the plastic preforms can be transformed into the plastic containers through the application of a flowable medium, wherein the blow-molding device has at least two side parts which are arranged at least indirectly on blow-mold carriers, wherein the side parts are arranged on the blow-mold carriers by an attachment device is provided. The attachment device also has a return which, at least temporarily during a working mode, pushes at least one side part towards the blow-mold carrier on which the side part is arranged.

Claims

1. A transforming device for transforming plastic preforms into plastic containers, comprising a blow-moulding device which forms a cavity inside which the plastic preforms can be transformed into the plastic containers through the application of a flowable medium, wherein the blow-moulding device has at least two side parts which are arranged at least indirectly on blow-mould carriers, wherein the side parts are arranged at least indirectly on the blow-mould carriers by an attachment device, wherein the attachment device also has a return which, at least temporarily during a working mode, pushes at least one side part towards the blow-mould carrier on which said side part is arranged, and wherein the attachment device has a bayonet-type attachment element for attaching the blow-mould part to the blow-mould carrier part.

2. The transforming device according to claim 1, wherein the transforming device has an advancing device which is suitable and intended for pushing one side part towards the other side part at least temporarily before or during a transforming operation.

3. The transforming device according to claim 2, wherein the advancing device has, in at least one intermediate space between the blow-mould carrier and the side part assigned thereto, a receiving chamber to which a flowable medium can be applied, as a result of the application of which the blow-mould carrier and the side part assigned thereto can be pushed apart.

4. The transforming device according to claim 1, wherein the attachment device, in a working mode of the transforming device, allows mechanical play between the blow-mould carrier and the blow-mould part arranged on said blow-mould carrier.

5. The transforming device according to claim 1, wherein blow-mould carrier shells are attached to the blow-mould carriers by the attachment device and the side parts are arranged on said blow-mould carrier shells, wherein the return preferably pushes at least one blow-mould carrier shell towards the blow-mould carrier on which said blow-mould carrier shell is arranged.

6. The transforming device according claim 1, wherein at least one blow-mould carrier shell has a first surface facing towards the blow-mould carrier assigned to said blow-mould carrier shell and a second surface facing towards said blow-mould carrier, and both the first surface and the second surface each partially delimit a pressure cushion.

7. The transforming device according to claim 1, wherein at least one return comprises a spring element.

8. The transforming device according to claim 6, wherein the spring element is preloaded to push the blow-mould part and/or the blow-mould carrier shell towards the blow-mould carrier part.

9. The transforming device according to claim 1, wherein the blow-mould carrier shell is held on the blow-mould carrier in a form-fitting and force-fitting manner and/or the blow-mould carrier shell also holds the blow-mould part in a form-fitting and force-fitting manner.

10. The transforming device according to claim 1, wherein at least one blow-mould carrier shell has channels for conducting a temperature control medium.

11. The transforming device according to claim 1, wherein there is arranged on at least one blow-mould carrier shell at least one force-deflecting element which diverts away any forces occurring during a transformation process, in particular axial forces on the blow-mould carrier assigned to said blow-mould carrier shell.

12. The transforming device according to claim 1, wherein at least one mould carrier shell has a V-shaped contour on a first side and a curved contour on a second side located opposite the first side.

13. A method for transforming plastic preforms into plastic containers, comprising the steps of: providing a blow-moulding device which forms a cavity, such that the plastic preforms are transformed into the plastic containers inside said cavity through the application of a flowable medium, providing with the blow-moulding device at least two side parts which are arranged at least indirectly on blow-mould carriers, wherein the side parts are arranged on the blow-mould carriers, wherein the attachment device also has a return and a bayonet-type attachment element for attaching the blow-mould part to the blow-mould carrier part and at least temporarily during a working mode, pushing at least one side part towards the blow-mould carrier on which said side part is arranged.

Description

BRIEF DESCRIPTION

(1) Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

(2) FIG. 1 shows a schematic diagram of a system for transforming plastic preforms into plastic containers;

(3) FIG. 2 shows a schematic diagram of a transforming device;

(4) FIG. 3 shows a view of a transforming device;

(5) FIG. 4 shows a view of the transforming device of FIG. 3 with the blow-mould carrier removed;

(6) FIG. 5 shows a diagram of a blow-mould carrier shell;

(7) FIG. 6 shows a diagram of an inner side of a blow-mould carrier part;

(8) FIG. 7 shows a detail of the diagram shown in FIG. 6;

(9) FIG. 8 shows a detail of the diagram shown in FIG. 5;

(10) FIG. 9 shows a sectional view of a blow mould arranged directly on a blow-mould carrier;

(11) FIG. 10 shows a detail view of an attachment mechanism;

(12) FIG. 11 shows a diagram of a transforming device arranged on a carrier;

(13) FIGS. 12a, b show two embodiments of blow-moulding devices; and

(14) FIG. 13 shows a diagram of a blow mould in a further embodiment.

DETAILED DESCRIPTION

(15) FIG. 1 shows a highly schematic diagram of a system 50 for transforming plastic preforms 10 into plastic containers 15. The plastic preforms 10 are fed to the transforming device via a feed device, such as a feed starwheel 52 for example. This transforming device 1 has a carrier 2 which is able to rotate about an axis of rotation D and on which a plurality of transforming devices are arranged, in each case on the outer circumference. Only two transforming devices 1 have been shown here. After the transforming operation, the finished containers 15 are conveyed away via a discharge device, such as a discharge starwheel 54.

(16) FIG. 2 shows a schematic diagram of a transforming device. Said transforming device has two blow-mould carriers 8a, 8b. Blow-mould carrier shells 6a, 6b are respectively arranged on said blow-mould carrier parts, and blow-mould side parts 4a, 4b, which are components of the blow-moulding device denoted 4 in its entirety, are in turn arranged on the blow-mould carrier shells 6a, 6b. To open and close the blow mould, the two blow-mould carriers 8a, 8b are unfolded from one another together with the blow-mould carrier shells arranged thereon and the blow-mould parts, so that a plastic preform 10 can be introduced into a cavity 5 that is formed between the blow-mould parts 4a, 4b. The plastic preform is then expanded inside this cavity.

(17) Reference 20 denotes in a highly schematic manner an attachment device by which the blow-mould carrier shell 6b is arranged on the blow-mould carrier 8b. Reference 30 denotes, again in a highly schematic manner, a pressure cushion which can be filled for example with compressed air during the expansion process in order thus to push the blow-mould carrier shell part 6b away from the blow-mould carrier part 8b and in this way move the blow-mould part 4b arranged on said blow-mould carrier shell 6b towards the blow-mould part 4a.

(18) As shown with reference to FIG. 2, this attachment element 20 is arranged in such a way that it extends perpendicular to a plane E that in the closed state is formed between the two blow-mould parts 4a and 4b. The attachment element 20 is also arranged centrally relative to the blow-mould carrier part 8b, and also relative to the blow-mould part 4b. In this way, a central introduction of force can be achieved. Reference 5 denotes the cavity inside which the plastic preforms are expanded to form the plastic containers.

(19) FIG. 3 shows a more detailed diagram of a transforming device 1, but the blow-mould parts are not shown here. The blow-mould carrier shells 6a, 6b are respectively arranged on the blow-mould carriers 8a, 8b. Reference 42 denotes a first locking element, which is arranged pivotably on the blow-mould carrier part 8b. Said first locking element can engage in a further locking element 44 in order thus to lock the blow mould during the expansion process.

(20) Reference 20 denotes in a highly schematic manner an attachment device by means of which the blow-mould carrier shell 6a is attached to the blow-mould carrier part 8a. In the advantageous embodiment shown here, two such attachment devices are provided, which are arranged here one above the other.

(21) FIG. 4 shows a further diagram of the device shown in FIG. 3, the blow-mould carriers having been removed here so that the blow-mould carrier shell part 6a and 6b can be seen directly.

(22) Reference 34 denotes a connection by which a temperature control medium can be fed to the blow-mould carrier shell 8a. In addition, a second connection (not shown) is also provided for returning the temperature control medium. The second blow-mould carrier shell also has corresponding connections.

(23) Reference 32 denotes a connection by means of which a pressure cushion can be supplied. To this end, there is formed on the blow-mould carrier shell part 6a a surface 16a which at the same time also delimits said pressure cushion. The pressure cushion is thus formed between the blow-mould carrier part (not shown in FIG. 4) and the carrier shell part 6a.

(24) Reference 14 in FIG. 4 denotes a spring element which serves to bias the carrier shell part 6a towards the blow-mould carrier part 8a. Reference 28 here denotes a hand lever, by which the locking mechanism between the blow-mould carrier part and the carrier shell part can be released and locked.

(25) Reference 48 denotes a U-shaped guide unit; the corresponding mating piece is screwed into the mould carrier shell. Reference 45 denotes a locking cassette which fixes and pneumatically secures the mould carrier shell. The cassette is fixedly screwed onto the mould carrier shell. Reference 49 denotes a throttle in the supply bore for the pressure cushion.

(26) FIG. 5 shows a diagram of the blow-mould carrier shell 6a or 6b. It is once again possible to see here the connections 34 and 36 for supplying and conveying away the temperature control medium. In addition, it is also possible to see the connection 32, via which air can be supplied to the pressure cushion.

(27) Also formed on the carrier shell part 6a, 6b, as mentioned above, are the surfaces 16, 16a which also form the pressure cushion. This pressure cushion can be supplied with compressed air via feed openings 23a, 23b.

(28) It can be seen that the blow-mould carrier shell 6a, 6b is V-shaped here, that is to say the two surfaces 16, 16a are at an angle to one another. The introduction of force to attach the blow-mould carrier shell 6a, 6b to the blow-mould carrier part takes place between the two surfaces 16, 16a, that is to say centrally between said surfaces. The engagement means 18a, 18b, which form part of the bayonet 18, are used for this purpose.

(29) FIG. 6 shows a diagram of the blow-mould carrier 8a. The attachment device 20 can once again be seen here. As mentioned above, this attachment device 20 has the lever 28, which brings about a rotation of an engagement means 17. Arranged on this engagement means 17 are two protrusions 17a and 17b which extend in the radial direction and which engage in corresponding engagement means or recesses 18a, 18b of the attachment element 18 (i.e. of the bayonet) in order to lock the carrier shell part. Both the engagement means 17 and the attachment element are thus components of the attachment device. The same also applies to the spring element 14.

(30) Reference 24 denotes a surface of the blow-mould carrier part which cooperates with the surface 16 (cf. FIG. 5) of the carrier shell part 4a, 4b in order thus to form the pressure cushion.

(31) Reference 33 denotes a peripheral sealing device, by means of which sealing can take place relative to the surface 16. In this way, the pressure cushion can be formed.

(32) FIG. 7 shows an enlarged diagram of the blow-mould carrier part shown in FIG. 6. The return device or spring shown in FIG. 2 is not shown here but is located between the wall of the blow-mould carrier part and the main body 35 of the actuating device 20. In this way, the actuating device is pressed in FIG. 7 in the direction of the arrow P by the spring element. In this way, however, the blow-mould carrier shell (not shown) is also pushed towards the blow-mould carrier 8a and is returned again therefrom during the working process once pressure has ceased to be applied to the pressure cushion.

(33) FIG. 8 shows a detail of the blow-mould carrier shell 6a. The engagement element 18 can once again be seen here. This engagement element 18 has two grooves 18a and 18b, in which the two protrusions 17a and 17b (cf. FIG. 7) engage. By rotating the lever 28, the blow-mould carrier shell 6a and the blow-mould carrier part 8a can in this way be pulled closer towards one another. The locking is thus made possible.

(34) FIG. 9 shows a diagram of two side parts 4a, 4b arranged on blow-mould carrier parts 8a, 8b. Reference 20 in each case denotes the attachment device which holds the side parts 4a, 4b directly on the blow-mould carrier parts 8a, 8b. In the embodiment shown in FIG. 9, therefore, no blow-mould carrier shell is provided which is arranged between the blow-mould carrier parts 8a, 8b and the side parts 4a, 4b.

(35) Reference 66 denotes a further guide mechanism which guides a movement of the side part 4a relative to the blow-mould carrier part 8a in the direction P1. This guide mechanism 66 is at one side arranged on, for example screwed onto, the blow-mould carrier part 8a via an attachment means 68. At the other side, this guide mechanism 66 has a protrusion 67 extending here in the direction P1, that is to say in a radial direction. Arranged on this protrusion 67, which engages in a recess 69 arranged on the blow-mould part 4a, is a sliding layer 67a which enables easy movement of the blow-mould part 4a relative to the blow-mould carrier part 8a. The lefthand blow-mould part 4a is thus arranged such as to be able to move relative to the blow-mould carrier part 8a in the direction of the arrow P1.

(36) The second side part 4b is rigidly arranged on the blow-mould carrier part 8b assigned thereto. Instead of a guide mechanism, here a securing mechanism 60 is provided which, in addition to the attachment device 20, secures the blow-mould side part 4b, that is to say the right-hand side part, relative to the blow-mould carrier part 8b.

(37) In general, preferably at least one side part 4a, 4b is arranged on the blow-mould carrier part 8a, 8b assigned thereto via at least two attachment devices 20 which are preferably arranged one above the other.

(38) FIG. 10 shows a detailed diagram of an attachment device 20. Here, the engagement element 18 in the form of a bayonet sleeve is fixedly screwed onto the respective side part 4a. By rotating an adjusting nut 21, the engagement means or cylindrical pins slide along the guide surface of the bayonet sleeve 18. In this way, a preloading of the spring element 14 is generated, which pulls the side part 4a towards the blow-mould carrier part 8a. In this way, a detachable connection is obtained between the side part 4a and the blow-mould carrier part 8a, the connection force being defined by the preloading of the spring element 14. This connection force can be varied by way of a screw 25.

(39) In the working mode, the spring force is overcome by actuating the pressure cushion and the side part 4a executes a horizontal movement towards the mid-point of the blowing station so as to minimize the mould gap to the respective other side part. Once the pressure of the pressure cushion has been released, the spring element 14 returns the side part to the original position.

(40) FIG. 11 shows a further diagram of a transforming device 1 arranged on a carrier 2, such as, in particular, a blowing wheel. Here, reference 10 again denotes a plastic preform and reference 7 denotes a stretching rod which serves to stretch the plastic preforms in their longitudinal direction. Reference 72 denotes a drive device such as, in particular, a linear motor which generates a movement of the stretching rod in the longitudinal direction of the plastic preforms 10. Reference 72 denotes a cooling device for cooling the drive device 72, and reference 76 denotes a control device for controlling the drive device, such as, in particular but not exclusively, an inverter.

(41) FIGS. 12a, 12b show two possible embodiments of blow-moulding devices arranged on a blow-mould carrier. In the embodiment shown in FIG. 12a, the blow-mould parts 4a, 4b are respectively arranged on the blow-mould carrier parts 8a, 8b via blow-mould carrier shells 6a, 6b. One or more pressure cushions 30 are formed here between the blow-mould carrier part 8a and the blow-mould carrier shell part 6a arranged on said blow-mould carrier part 8a. Also provided in the blow-mould carrier shell parts 6a, 6b are temperature control bores 45, through which a flowable temperature control medium can flow.

(42) In the embodiment shown in FIG. 12b, the blow mould is or the side parts 4a, 4b of the blow mould are arranged directly on the respective blow-mould carrier parts 8a, 8b. A pressure cushion 30 is thus formed here directly between the blow-mould carrier part 8a and the side part 4a arranged on said blow-mould carrier part 8a. Reference 45 again denotes temperature control bores or channels, through which a flowable temperature control medium can flow. Reference FS in each case denotes the mould gap, which can be minimized by the pressure cushion 30. The blow mould or the side parts 4a and 4b thereof are configured as so-called “full moulds”, which simultaneously perform the functions of the mould carrier shells (missing here) and the actual blow mould. The full moulds thus also have a V-shaped outer contour, as well as a corresponding pressure cushion arrangement.

(43) FIG. 13 shows a further diagram of a side part 4a. Here, this side part has two cavities for forming plastic bottles. FIG. 13 thus shows a double cavity, by means of which two containers can be blown (in particular substantially simultaneously).

(44) Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

(45) For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements. The mention of a “unit” or a “module” does not preclude the use of more than one unit or module.

LIST OF REFERENCES

(46) 1 transforming device 2 carrier 4a, 4b blow-mould side parts 4 cavity 5a, 5b cavity 6a, 6b blow-mould carrier shells 8a, 8b blow-mould carrier parts 10 plastic preforms 14 spring element 15 plastic containers 16, 16a surface 17 engagement means 17a, 17b protrusions 18 engagement element 18a, 18b engagement means 20 attachment device 21 adjusting nut 23a, 23b feed openings 24 surface 25 screw 28 lever 30 pressure cushion 32, 34 connections 33 peripheral sealing device 35 main body 36 feed connection 42 first locking element 44 further locking element 48 guide unit 49 throttle 50 system 52 feed starwheel 54 discharge starwheel 60 securing mechanism 66 guide mechanism 67 protrusion 67a sliding layer 68 attachment means 69 recess 72 drive device 74 cooling device 76 control device D axis of rotation E plane P arrow P1 movement direction