METHOD, SYSTEM, AND BLOW MOLDING MACHINE FOR BLOW MODLING A CONTAINER

Abstract

A method for blow molding a container having a fiber-based shell (20) is disclosed. The method comprises the steps of providing a fiber-based shell (20) introducing a preform (30) into the fiber-based shell (20) in order to produce a semi-finished product (60) gripping the semi-finished product (60) by means of a gripper (40) transferring the semi-finished product (60) into a blow molding tool (50) and blowing the container. The gripper (40) presses an inner wall (21) of the fiber-based shell (20) onto an outer surface (31) of the preform (30).

Claims

1. A method for blow molding a container having a fiber-based shell (20), comprising the steps of providing a fiber-based shell (20), introducing a preform (30) into the fiber-based shell (20) in order to produce a semi-finished product (60), gripping the semi-finished product (60) by means of a gripper (40), transferring the semi-finished product (60) into a blow molding tool (50), and blowing the container, wherein the gripper (40) presses an inner wall (21) of the fiber-based shell (20) onto an outer surface (31) of the preform (30).

2. The method according to claim 1, wherein the gripper (40) surrounds the semi-finished product (60) continuously during the blowing process.

3. The method according to claim 1, wherein the gripper (40) is in contact with the blow molding tool (50) during the blowing process.

4. The method according to claim 1, further comprising, with the gripper (40), gripping the semi-finished product (60) both below a support ring (32) of the preform (30) and above the support ring (32).

5. The method according to claim 4, further comprising as the preform (30) is introduced into the fiber-based shell (20), bringing an upper end (22) of the fiber-based shell (20) into contact with the support ring (32).

6. The method according to claim 1, wherein the gripper (40) grips and clamps the semi-finished product (60) from at least two sides.

7. A system composed of a gripper (40) and a head plate (51) of a blow molding tool (50) for carrying out the method according to claim 1, wherein the gripper (40) has a first gripping jaw (43) with a height (H) and the head plate (51) has a recess with a depth corresponding to the height (H) or has a projection (52) with the height (H).

8. The system according to claim 7, wherein the recess has an outer contour which substantially corresponds to an outer contour of the gripping jaw (43).

9. The system according to claim 7, wherein the gripper (40) has a second gripping jaw (44), which is spaced apart from the first gripping jaw (43) in such a way that a support ring is introducible between the first gripping jaw (43) and the second gripping jaw (44).

10. The system according to claim 7, wherein the gripper (40) has a first member (41) and a second member (42), on each of which members (41, 42) a first gripping jaw (43) is arranged.

11. The system according to claim 9, wherein a second gripping jaw (44) is arranged at least on one of the first and the second members (41, 42).

12. The system according to claim 7, wherein the first gripping jaw (43) has a gripping surface (431) which extends along a circular ring over an angle of at least 30°.

13. The system according to claim 9, wherein the second gripping jaw (44) has a gripping surface (441) which extends along a circular ring over an angle of at least 30°.

14. The system according to claim 9, wherein the first gripping jaw has a first gripping surface and the second gripping jaw has a second gripping surface, the first gripping surface (431) and the second gripping surface (441) are offset relative to one another in a radial direction.

15. A blow molding machine comprising a system according to claim 7.

16. The method according to claim 3, wherein the gripper (40) is in contact with a head plate (51) of the blow molding tool (50), during the blowing process.

17. The system according to claim 11, wherein a second gripping jaw (44) is arranged on each, of the first and the second members (41, 42).

18. The system according to claim 14, wherein the first gripping surface (431) and the second gripping surface (441) are offset relative to one another in a radial direction by a wall thickness (W) of the fiber-based shell.

Description

[0057] The invention is explained below with reference to schematic figures by means of exemplary embodiments. These show:

[0058] FIG. 1: a perspective view of a member of a gripper;

[0059] FIG. 2: a preform;

[0060] FIG. 3: a perspective view of a fiber-based shell;

[0061] FIG. 4: a cross section through a semi-finished product during the gripping;

[0062] FIG. 5: a perspective view of a blow mold before the closing;

[0063] FIG. 6: a detailed view of the blow mold from FIG. 5, after the closing.

[0064] FIG. 1 shows a perspective view of a member 41 of a gripper 40 (see FIG. 5). The member 41 has a first gripping jaw 43 and a second gripping jaw 44. A gripping surface 431 is located on the first gripping jaw 43, and a gripping surface 441 is located on the second gripping jaw 44. The gripping surfaces 441 and 431 each extend along a circular ring over an angle of 30°. The first gripping jaw 43 is axially spaced apart from the second gripping jaw 44. In cross section, the first gripping jaw 43 forms a substantially C-shaped cross section with the second gripping jaw 44. This C-shaped cross section is designed to receive a corresponding support ring 32 (see FIG. 2). In relation to the second gripping jaw 44, the first gripping jaw 43 is offset radially outwards (see also FIG. 4).

[0065] In particular on the gripping surface 431 of the first gripping jaw 43, contours can be formed, which improve the friction between this gripping surface 431 and a fiber-based shell 20 to be gripped.

[0066] FIG. 2 shows a preform 30. The preform 30 has an elongate body with a preform base. A support ring 32, which divides the preform 30, is arranged on the preform 30. In the present illustration, a closure region 33 is arranged above the support ring 32. In the present illustration, below the support ring 32 the preform body has four projections 34, on each of which an outer surface 31 is formed. For the sake of improved clarity, only one of the projections 34 and one of the outer surfaces 31 are provided with reference signs.

[0067] FIG. 3 shows a perspective view of a fiber-based shell 20. The fiber-based shell 20 has an upper end 22 which is substantially in the shape of a hollow cylinder. An inner wall 21 is formed at this upper end.

[0068] FIG. 4 shows a cross section through a semi-finished product 60 during the gripping. In the illustration according to FIG. 4, a preform 30 (see FIG. 2) is thus introduced into a fiber-based shell 20 (see FIG. 3). The fiber-based shell 20 has a wall with a wall thickness W, and this wall has an inner wall 21 and an outer wall 23. The inner wall 21 of the fiber-based shell 20 is in contact with an outer surface 31 of the preform 30. The outer surface 31 is formed on a projection 34. There is already a clamping effect between the preform 30 and the fiber-based shell 20. FIG. 4 also shows a first member 41 of a gripper 40 (see FIG. 5). The member 41 has a first gripping jaw 43 and a second gripping jaw 44. The gripping surface 431 of the first gripping jaw 43 is just in contact with the outer wall 23 of the fiber-based shell 20. FIG. 4 shows that at this point in time the second gripping jaw 44 is spaced apart from an outer surface 35 of the closure region 33 with the distance D. To fix the fiber-based shell 20 on the preform 30, the member 41 is moved towards the preform 30 until the distance D disappears. In the process, the wall thickness W of the fiber-based shell 20 is compressed by the distance D and accordingly pressed onto the projection 34. The distance D is smaller than the wall thickness W and in the present case is approximately half of the wall thickness W. Here, the gripping surface 431 of the first gripping jaw 43 is radially spaced apart from the gripping surface 441 of the second gripping jaw 44. The distance is the difference between the wall thickness W and the distance D plus the height of the projection 34, i.e. the distance between the outer surface 31 and the outer surface 35 of the closure region 33. Of course, a second member 42, which for the sake of simplicity is not shown, is arranged opposite the member 41. In the present case, the second member 42 is designed like the first member 41.

[0069] As can also be seen in FIG. 4, the first gripping jaw 43 is offset radially outwards with respect to the second gripping jaw 44. In the present case, the offset equals a height of the projection 34 relative to the outer surface 35 of the closure region plus approximately half of the wall thickness W.

[0070] The height H of the first gripping jaw 43 is also shown.

[0071] FIG. 5 shows a perspective view of a blow mold 50 before the closing. A semi-finished product 60 is introduced into an opened blow mold 50 by means of a gripper 40, which has a first member 41 and a second member 42. The two members 41 and 42 of the gripper 40 are arranged on two gripper arms, not shown here, which can be pivoted together into the blow mold 50 and out.

[0072] The blow mold 50 has two blow mold halves, which are not described in greater detail, and a half of a head plate 51 is arranged on each blow mold half. An elevation is formed on the head plate 51, on which elevation a projection 52 is formed. The projection 52 has a height that corresponds to the height H of the first gripping jaw 43 (see FIG. 4).

[0073] FIG. 6 shows a detailed view of the blow mold 50 after the closing. The support ring 32 now lies on the projections 52 (see FIG. 5) of the head plate 51. The members 41 and 42 lie essentially on the head plate 51 between the projections 52. Since the members 41 and 42 rest on the head plate, they are precisely positioned in the axial direction. In this illustration, the support ring lies only on the projections 52. Alternatively, the projections 52 can form, together with a surface of each of the first gripping jaws 43 (see FIG. 4), a common surface for supporting the support ring 32. It is also possible that the members 41 and 42 are still slightly spaced apart from the head plate 51 in the position shown in FIG. 6 in order to prevent excessive friction as the blow mold 50 is brought together. In this case, during the blowing process the members 41 and 42 can be pressed onto the head plate 51, which correspondingly forms a counter bearing.