Method of Manufacturing a Plastic Canister

Abstract

Disclosed is a method for manufacturing a container made of plastic, including the following steps: continuously extruding a hose, positioning an opened blow mold around the hose, so that the hose is arranged between the two blow mold halves, closing a hose gripper arranged at the blow mold to clamp the hose and simultaneously keeping the hose open at its upper side to form an inlet opening, separating the hose above the hose gripper to form the preform, horizontally moving the blow mold together with the preform hanging therein and held by the hose gripper into a blowing position, moving a blow mandrel assembly from above into the inlet opening of the preform, closing the blow mold halves, and inflating the preform in the blow mold to form a container.

Claims

1. A method of manufacturing a container made of plastic, comprising the following steps: continuously extruding a hose, positioning an opened blow mold around the hose so that the hose is arranged between two blow mold halves, closing a hose gripper arranged at the blow mold to clamp the hose and simultaneously holding the hose open at its upper side to form an inlet opening, separating the hose above the hose gripper to form a preform, horizontally moving the blow mold together with the preform hanging therein and held by the hose gripper in a blowing position, inserting a blow mandrel assembly from above into the inlet opening of the preform, closing the blow mold halves, and inflating the preform in the blow mold to form a container. wherein the hose gripper clamps the hose with two gripping areas at two locations spaced apart from each other, so that the inlet opening comprises an oval cross-section.

2. Method according claim 1, wherein the hose gripper comprises at least one gripping element on each blow mold half.

3. Method according to claim 2, wherein the at least one gripping element is spring-loaded in a closing direction via springs.

4. Method according to claim 1, wherein when the hose is clamped the two gripping areas are moved towards each other to deform the inlet opening.

5. Method according to claim 1, wherein the container comprises a spout for pouring into and out of the container.

6. Method according to claim 1, wherein compressed air is injected into the preform for pre-blowing the preform before the blow mold halves are closed.

7. Method according to claim 6, wherein the preform is inflated beyond an inner mold dimension of the blow mold during pre-blowing.

8. Method according claim 1, wherein the blow mandrel assembly is moved horizontally after inserting into the inlet opening and before closing the blow mold halves.

9. Method according to claim 5, wherein the blow mandrel assembly comprises at least one compressed air outlet arranged inclined at its lower side and, when the container is inflated, material is blown away via the compressed air outlet to define a venting channel.

10. A blow mold for manufacturing a container made of plastic, comprising: two blow mold halves, forming the container, and a hose gripper with at least one gripping element on an upper side of one blow mold half and at least one opposite gripping element on an upper side of another blow mold half, wherein the gripping elements are movable relative to the blow mold half, so that a hose arranged between opened blow mold halves is clampable by the gripping elements without closing the blow mold halves. wherein the hose gripper includes two gripping areas, each of which is for clamping the hose, and wherein the two gripping areas are spaced apart from each other to form an inlet opening with oval cross-section in the hose.

11. Blow mold according to claim 10, comprising at least one spring per gripping element which biases the gripping element in a closing direction.

12. Blow mold according to claim 10, wherein the two gripping areas are movable towards each other for deforming the inlet opening.

13. Blow mold according to claim 10, further comprising a holding device which is configured to hold and release the gripping element.

14. Blow mold according to claim 11, further comprising a holding device which is configured to hold and release the gripping element.

15. Method according to claim 1, wherein the hose is clampable between the at least one gripping element on each blow mold half.

16. Method according to claim 3, wherein the springs are relaxed to clamp the hose.

17. Method according to claim 3, wherein the springs are tensioned during closing of the blow mold halves.

18. Method according to claim 3, wherein the springs are held in a tensioned state during opening of the blow mold halves.

19. Method according to claim 5, wherein a vertical portion of a venting channel of the container protrudes into the spout.

20. Method according to claim 19, wherein the blow mandrel assembly forming with a main blow mandrel the spout and forming with an ancillary blow mandrel the vertical portion of the venting channel when the blow mold halves are closing.

Description

[0039] Further details, advantages and features of the present invention will be apparent from the following description of an example embodiment with reference to the drawings.

[0040] FIG. 1 shows a schematic view illustrating the method of the invention according to an embodiment,

[0041] FIG. 2 shows a top view of a blow mold of the invention for carrying out the method of the invention according to the embodiment,

[0042] FIG. 3 shows a top view of the closed blow mold of FIG. 2,

[0043] FIG. 4 shows a top view of a variant of the blow mold of FIG. 2,

[0044] FIG. 5 shows a top view of a container produced by the method of the invention according to the embodiment,

[0045] FIG. 6 shows the section A-A indicated in FIG. 5,

[0046] FIG. 7 shows a detailed view of the blow mold of the invention for carrying out the method of the invention according to the embodiment,

[0047] FIG. 8 shows a detailed view of a blow mandrel assembly for carrying out the method of the invention according to the embodiment, and

[0048] FIG. 9 shows the section B-B shown in FIG. 8.

[0049] The method of the invention for producing a container 50 by using a blow mold 1 according to the invention is explained in detail below with reference to FIGS. 1 to 9. Reference is always made to all figures, unless otherwise mentioned in detail.

[0050] FIG. 1 shows an assembly 100, which can be used in carrying out the method. The illustration is merely schematic.

[0051] The assembly 100 comprises a blow head 101, with which a hose 102 made of plastic is continuously extruded. The hose 102 thereby hangs downwardly from the blow head 101 along the vertical 110.

[0052] Further, the schematic illustration in FIG. 1 shows that the assembly 100 comprises a blow mold 1. This blow mold 1 further comprises two opposite blow mold halves 2. A hose gripper 3 is arranged on these blow mold halves 2.

[0053] Above the hose gripper 3 is a cutting device 103 for cutting and simultaneously closing the hose 102.

[0054] In the method sequence, the hose 102 is extruded continuously. The blow mold 1 is regularly positioned at the hose 102 with the blow mold halves 2 opened. Further, the blow mold halves 2 are then not closed, but the hose 102 is merely clamped with the hose gripper 3. The hose 102 is then cut off above the blow gripper 3 by the cutting device 103, so that the preform 106 remains hanging between the two blow mold halves 2. Without closing the blow mold halves 2, the blow mold 1 together with the preform 106 hanging therein is moved along the horizontal 111 into a blowing position 105. As a result, the blow mold 1 is no longer located under the continuously further extruding hose 102.

[0055] At the blowing position 105, the blow mandrel assembly 30 shown merely schematically in FIG. 1 is inserted into the preform 106 via a movement along the vertical 110. This is followed by closing of the blow mold halves 2 and inflating of the preform 106 to form the container 50, as shown for example in FIGS. 5 and 6.

[0056] In the following, the schematic structure of the blow mold 1 is described in detail with reference to FIGS. 2 to 4. FIG. 2 shows a top view of the opened blow mold 1. FIG. 3 shows a top view of the closed blow mold 1. FIG. 4 shows a top view of an alternative form of the blow mold 1, illustrated in the opened state.

[0057] As already described, the blow mold 1 comprises two blow mold halves 2 and a hose gripper 3. The hose gripper 3 further comprises two gripping elements 4. On each blow mold half 2, a gripping element 4 is arranged on the upper side. Each gripping element 4 is movable along the horizontal 111 parallel to the mold closing direction 11 relative to the blow mold halves 2. In FIGS. 2 to 4, the hose gripper 3 is closed. The two opposite gripping elements 4 have moved towards each other. The preform 106 is clamped at two spaced gripping areas 5. As the two gripping areas 5 are spaced apart from each other, an inlet opening 104 remains in the preform 106 between the two gripping areas 5. The blow mandrel assembly 30 can be inserted through this inlet opening 104 at the blowing position 105, before the blow mold halves 2 are closed along the mold closing direction 11.

[0058] FIGS. 2 to 4 show merely schematically that the gripping elements 4 are biased in the direction of their closed position by means of springs 6. These springs 6 press the gripping elements 4 toward each other. By means of holding devices 7, for example formed as pneumatic or hydraulic cylinders, the gripping elements 4 can be held in their open position against the spring force.

[0059] FIG. 3 shows a top view of blow mold 1 in the closed position. The blow mold halves 2 are completely closed. As a result, the inlet opening 104 is closed. The blow mandrel assembly 30 protrudes into the preform 106 from above.

[0060] FIG. 4 shows a variant, in which the gripping elements 4 on the corresponding blow mold halves 2 are designed in two parts. The gripping elements 4 are movable towards each other in such a way that the gripping areas 5 are movable towards each other. This allows the oval form of the inlet opening 104 to be changed to a rounder form.

[0061] FIG. 5 shows a top view of the container 50 produced by the assembly 100 or rather the blow mold 1. FIG. 6 shows the section A-A indicated in FIG. 5.

[0062] Accordingly, the container 50 comprises an upper wall 51 and an opposite, not shown, bottom. The upper wall 51 and the bottom are connected via a circumferential surface 64 of the container 50. Thus, the upper wall 51, bottom and circumferential surface 64 form an inner space 52 of the container 50 for holding a liquid.

[0063] A handle 53 is formed at the upper wall 51. In front of the handle 53 is a spout 54 formed for pouring the liquid into and out of the inner space 52.

[0064] The spout 54 ends with an upper end 56. This upper end 56 is sealed by a cover, not shown, which can be screwed onto an external thread 55 of the spout 54.

[0065] Further, a venting channel 57 is located on the inner side of the top panel 51. The venting channel 57 is divided into a horizontal portion 58 and a vertical portion 59.

[0066] The venting channel 57 is formed by an outer channel wall 60 and an inner channel wall 61. The inner channel wall 61 is formed preferably through squeezing of the preform 106. Squeezing edges 8 (see FIG. 7) are used on the blow mold halves 2 for this purpose. The outer channel wall 60 is preferably an outer wall of the container 50.

[0067] The venting channel 57 protrudes with its vertical portion 59 into the spout 54. From the spout 54, the vertical portion 59 extends downward and merges into the horizontal portion 58. The horizontal portion 58 extends into the rear region of the container 50 and opens into the inner space 52. The horizontal portion 58 does not have to run exactly horizontally, but can also run in an inclined manner

[0068] By virtue of the fact that the venting channel 57 extends into the spout 54, the inner channel wall 61 divides the inner space of the spout 54 into a main opening 62, through which the liquid passes during pouring in and out, and a venting opening 63. It is preferably arranged that the venting opening 63 is substantially smaller in cross-section than the main opening 62. Preferably, the cross-sectional area of the venting opening 63 is at most 25%, preferably at most 20%, of the cross-sectional area of the main opening 62.

[0069] FIG. 7 shows an area of one of the two blow mold halves 2. It can be seen that the corresponding part of the mold cavity 10 is formed in the blow mold halves 2. Cutting edges 9 run around the mold cavity 10, which together with the cutting edges of the other blow mold halves 2 close and cut off the preform 106.

[0070] Further, FIG. 7 shows that the blow mold halves 2 respectively comprise a squeezing edge 8 that squeezes the preform 106 to form the inner channel wall 61. These squeezing edges 8 extend corresponding to the vertical portion 59 of the venting channel 57 also in the area of the spout 54.

[0071] FIG. 8 shows how the blow mandrel assembly 30 is inserted into the container 50. FIG. 9 shows the section B-B indicated in FIG. 8.

[0072] The blow mandrel assembly 30 comprises a main blow mandrel 31 and an ancillary blow mandrel 32. The main blow mandrel 31 is arranged in the area of the spout 54, when the blow mold halves 2 are closing and when the container 50 is inflated, and is thereby formative for the inside of the main opening 62. At the same time, the ancillary blow mandrel 32 is also arranged in the area of the spout 54, when the blow mold halves 2 are closed and when the container 50 is inflated, and is thereby formative for the inner surface of the venting opening 63 or rather of the vertical portion 59 of the venting channel 57.

[0073] As shown in section B-B in FIG. 9, the main blow mandrel 31 and the ancillary blow mandrel 32 are spaced apart from each other by a squeezing edge gap 36. Since the blow mandrel assembly 30 is already arranged in place when the blow mold halves 2 are closed, the two squeezing edges 8 squeeze the material into the squeezing edge gap 36. Through the corresponding position of the ancillary blow mandrel 32, no material is thereby squeezed into the venting channel 57 to be created, preferably the vertical portion 59.

[0074] The two blow mandrels 31, 32 each comprise a centric blow channel 33 for blowing compressed air into the inner space 52. A return flow channel 34 is respectively arranged around the blow channel 33.

[0075] Merely schematically, FIG. 8 shows that the ancillary blow mandrel 32 can comprise an inclined compressed air outlet 35 or several of these inclined compressed air outlets 35 on its underside. Air is blown out through this compressed air outlet 35 inclined to the vertical 110. This allows any material squeezed into the emerging venting channel 57 to be blown away, thereby facilitating the desired cross-sectional area of the venting channel 57.

[0076] Further, preferably at least one of the gripping elements 4 comprises a compressed air nozzle, which enables the preform 106 to be pre-blown, before the blow mold halves 2 are closed.

LIST OF REFERENCE SIGNS

[0077] 1 blow mold

[0078] 2 blow mold halves

[0079] 3 hose gripper

[0080] 4 gripping element

[0081] 5 gripping areas

[0082] 6 springs

[0083] 7 holding device

[0084] 8 squeezing edge

[0085] 9 cutting edge

[0086] 10 mold cavity

[0087] 11 mold closing direction

[0088] 30 blow mandrel assembly

[0089] 31 main blow mandrel

[0090] 32 ancillary blow mandrel

[0091] 33 blow channel

[0092] 34 return flow channel

[0093] 35 inclined-arranged compressed air outlet

[0094] 36 squeezing edge gap

[0095] 50 container

[0096] 51 upper bottom

[0097] 52 inner space

[0098] 53 handle

[0099] 54 spout

[0100] 55 external thread

[0101] 56 upper closure

[0102] 57 venting channel

[0103] 58 horizontal portion

[0104] 59 vertical portion

[0105] 60 outer channel wall

[0106] 61 inner channel wall

[0107] 62 main opening

[0108] 63 venting opening

[0109] 64 circumferential surface

[0110] 100 assembly

[0111] 101 blow head

[0112] 102 hose

[0113] 103 cutting device

[0114] 104 inlet opening

[0115] 105 blowing position

[0116] 106 preform

[0117] 110 vertical

[0118] 111 horizontal