Method for producing an internal screw thread on a container
Patent Information
- Application Number
- EP2024707055
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-02-27
- Filing Date
- 2024-02-26
- Publication Date
- 2026-01-07
AI Technical Summary
Existing methods for producing internal threads in containers, such as those used in plastic cosmetics containers, are time-consuming and require complex devices, leading to contamination and inefficiencies.
A method involving a thread cutter that positions the container upside down to cut the internal thread, utilizing a suction device to remove chips and a fluid channel for rinsing to minimize contamination, along with a device that includes a holding mechanism and rotating capabilities for integration into conventional production lines.
This approach allows for precise, efficient, and contamination-reduced production of internal threads, enabling precise thread sizes not achievable with conventional methods and facilitating easier integration into existing manufacturing processes.
Smart Images
Figure EP2024054801_06092024_PF_FP
Abstract
Description
[0001] Method for producing an internal thread on a container
[0002] The present invention relates to a method and a device for producing an internal thread on a container and to a corresponding container with an internal thread according to the preamble of the independent claims.
[0003] A wide variety of containers are needed in everyday use. Food and cosmetics, for example, are typically supplied in plastic containers which often have a screw cap. Depending on the application, closures are provided with an internal or an external thread. Typical applications for containers with an internal thread include canisters, barrels or hazardous goods containers. However, an internal thread can also be provided on ordinary bottles. The corresponding containers are often manufactured using the extrusion blow moulding process. The production of a precisely fitting thread is time-consuming and the associated equipment is complicated. For example, an internal thread can be produced or introduced using a folding core or using turning mandrels.
[0004] It is therefore an object of the invention to remedy at least one or more disadvantages of the prior art. In particular, a method and a device for introducing an internal thread into a container with a dispensing opening are to be provided that are simple, reliably repeatable, and preferably involve minimal tooling.
[0005] This object is achieved by the devices and methods defined in the independent patent claims. Further embodiments emerge from the dependent patent claims.
[0006] A method according to the invention for producing an internal thread in a container with a dispensing opening, in particular for producing an internal thread in a dispensing opening of a container, in particular an extrusion-blown container, comprises the steps:
[0007] - Position the container so that the dispensing opening is facing downwards,
[0008] - Providing a thread cutter adjacent to the dispensing opening,
[0009] - Cutting an internal thread in the container.
[0010] Cutting an internal thread with a thread cutter allows for very high precision, as this thread is not subject to negative shrinkage. At the same time, complicated applications or equipment are eliminated during the container blow-molding process. The thread is preferably created after the container has cooled down.
[0011] By positioning the container facing downwards, i.e., in a position where the container is open at the bottom, chips generated during thread cutting do not fall into the container. Contamination of the container is thus significantly reduced compared to machining from above.
[0012] Preferably, the chips generated during the cutting process are vacuumed away. This helps to reduce the amount of contamination in the container and also minimizes the amount of contamination in or with the device used to cut the thread.
[0013] This extraction process is preferably initiated before the cutting process. Depending on the configuration of the associated extraction device, a specific flow and, if necessary, a vacuum can be provided before the cutting process, which improves the extraction of the chips.
[0014] To extract the chips, a suction device can preferably be provided before cutting the internal thread.
[0015] To further protect the interior of the container from contamination, the container can be pressurized with a flushing fluid, particularly flushing air. The flushing fluid can also be applied before the cutting process begins. Furthermore, the flushing process, or the application of the flushing fluid, can also continue after the cutting process, so that the interior of the container is still flushed with the flushing fluid even after the cutting process, and any remaining chips can be blown out.
[0016] To accommodate the flushing fluid, the thread cutter may have a fluid channel through which the flushing fluid is introduced into the interior of the container. The thread cutter may, in particular, be designed to be substantially hollow.
[0017] By creating a fluid channel in the thread cutter, the flushing fluid can be introduced at the correct location without major effort. Complex devices for introducing the flushing fluid can be avoided.
[0018] Additionally or alternatively, provision may be made for the interior of the container to be supplied with the rinsing fluid through a further opening on the container.
[0019] For example, there are containers that have another opening in addition to the dispensing opening, such as a separate filling opening. With such containers, it is advisable to also apply the flushing fluid to the second opening, thus creating a corresponding overpressure in the container so that the chips can be discharged even more effectively.
[0020] The cutting process of the internal thread can be interrupted cyclically so that chips generated during the cutting process are broken up. If the chips remain small, they can be blown out more easily, as they are less likely to get caught.
[0021] During processing, in other words during the cutting process, the container can be held in a processing position, preferably by means of a positive locking mechanism. In this case, the processing position is a position in which a discharge opening of the container faces downward.
[0022] The positive locking mechanism allows the container to be held easily and securely, reducing unnecessary forces on the container.
[0023] In one form of the process, the container can be positioned upright before the cutting process, i.e., with its dispensing opening facing upwards, and then turned upside down before the cutting process. Typically, containers are transported in the production facility in the position of use, i.e., with the dispensing opening facing upwards.
[0024] After the cutting process, the container is preferably turned into an upright position. This allows it to be transported further in existing production facilities.
[0025] A further aspect relates to an extrusion-blown container having an internal thread, wherein the internal thread is manufactured, in particular cut, using a machining process. Preferably, the internal thread is manufactured using a process as described herein.
[0026] This makes it possible to provide a container with a very precise internal thread, particularly in a size that cannot be achieved using conventional manufacturing methods, such as folding cores.
[0027] A further aspect relates to a device for producing an internal thread, in particular in a method as described here, in particular in a container as described here. The device comprises a feed device for feeding containers, a holding device for positively holding a container and a device for cutting a thread. The device for cutting a thread is designed in particular as a thread cutter. The device also comprises a suction device for suctioning away chips produced by a cutting process.
[0028] Such a device makes it possible to produce an internal thread on a container using a machining process while simultaneously removing any resulting chips and thus avoiding excessive contamination. The suction device is preferably designed such that it precedes the thread-cutting device, meaning it can be positioned before the thread-cutting device engages the container. This allows the suction process to be started before the cutting process begins.
[0029] The device may also comprise a rotating device for turning the containers upside down before the cutting process and additionally or alternatively a rotating device for turning the containers upside down after the cutting process.
[0030] This allows the device to be installed in conventional production lines in which the containers are transported in an upright position.
[0031] The process is explained below using figures. It shows:
[0032] Figure 1 : A device for producing an internal thread; Figure 2 : a cross section through the device according to the
[0033] Figure 1 ;
[0034] Figure 3 : the cross-section according to Figure 2 in a further position;
[0035] Figure 4: the cross-section analogous to Figure 3 in an enlarged view;
[0036] Figure 5 : a further process step;
[0037] Figure 6 : a thread cutting process;
[0038] Figure 7 : the device according to Figure 1 after the thread cutting process.
[0039] Figure 1 shows a device 100 comprising a feeding device 101 and a device for removing 102 containers 30, both of which are not explicitly shown.
[0040] Figure 2 shows a cross-section through the device 100 according to Figure 1. The device 100 has a holding device 60 into which a container 30 can be introduced. In the present case, the holding device 60 has two holding jaws (not shown in more detail) for holding the container 30 in a form-fitting manner. A suction device 50 is arranged below the holding device 60. In the present case, the suction device 50 is designed concentrically around a thread cutter 40. The thread cutter 40 is placed adjacent to, and in the present case opposite, a dispensing opening 31. The dispensing opening 31 of the container 30 is directed downwards, in other words, the container 30 is upside down.
[0041] The holding device 50 is shown in an open position. The holding jaws (not shown in detail here) are open. The container 30 is held above the thread cutter 40 by means not shown in detail here, so that the dispensing opening 31 is arranged opposite the thread cutter 40. As can be seen, the suction device 50 is spaced from the holding device 60.
[0042] Figure 3 shows the next step, namely the clamping of the container 30 with the holding device 60. The container 30 is held in the holding jaws of the holding device 60 with a positive fit, so that it is immobile.
[0043] Figure 4 shows the cross-section analogous to Figure 3 in an enlarged view. As can be seen, the thread cutter 40 is formed with a fluid channel 41. The fluid channel 41 is formed in this case in that the thread cutter 40 is essentially hollow, i.e. has an essentially tubular configuration. The container 30 has a dispensing opening 31 which is arranged adjacent to and in this case opposite the thread cutter 40. The container 31 also has a container interior 32 and a plurality of further openings 33, which are, however, optional for each container. The suction device 50 extends around the thread cutter 40 and in this case is spaced apart from the holding device 60.
[0044] Figure 5 now shows the next process step. In this step, the suction device 50 is moved toward the container so that no false air enters the suction device 50. The suction process can then be started, and the thread cutter 40 can then be moved toward the container opening 31. The thread cutting process is shown below in Figure 6.
[0045] Figure 6 shows, as already explained, the thread cutting process. The suction device 50 is essentially in contact with the holding device 60 and thus the interior of the container 31 is essentially sealed off from the environment. The thread cutter 40 has already been screwed a short distance into the discharge opening 31 of the container 30. A flushing fluid, in this case flushing air, is introduced into the container interior 32 through the hollow thread cutter 40, i.e. through the fluid channel 41. This flushing air flows outwards along the thread cutter, i.e. in chip spaces between the thread cutter and the container neck, and entrains chips 21 which are created during thread cutting. These are sucked away by means of the suction device 50. A so-called blind hole tap is preferably used.
[0046] Figure 7 now shows the device 100 according to Figure 1, with the previously processed container 30 rotated back to its original position. The discharge opening 31 of the container 30 now points upward again, and the container 30 is in an upright position. Accordingly, it can be further processed in conventional production lines.
Claims
Patent claims 1. A method for producing an internal thread (20) in a container (30) with a dispensing opening (31), in particular in an extrusion-blown container, comprising the steps: - Providing the container (30) so that the dispensing opening (31) is directed downwards, - providing a thread cutter (40) adjacent to the dispensing opening (31), - Cutting an internal thread (20) in the container.
2. Method according to claim 1, characterized in that chips (21) produced by the cutting process are sucked away.
3. Method according to claim 2, characterized in that the suction process is started before the cutting process.
4. Method according to claim 3, characterized in that a suction device (50) is provided for sucking away the chips (21) before cutting the internal thread (20).
5. Method according to one of claims 1 to 4, characterized in that an interior (32) of the container (30) is subjected to a rinsing fluid, in particular rinsing air.
6. Method according to claim 5, characterized in that, for the purpose of applying the flushing fluid, the thread cutter has a fluid channel (41) through which the flushing fluid is introduced into the interior (32) of the container (31).
7. Method according to claim 5 or 6, characterized in that the interior (32) of the container (30) is supplied with the rinsing fluid through a further opening (33) on the container (30).
8. Method according to one of claims 1 to 7, characterized in that the cutting process of the internal thread (20) is cyclically io is interrupted so that chips (21) produced by the cutting process are broken.
9. Method according to one of claims 1 to 8, characterized in that the container (30) is held in a processing position by positive locking during the cutting process.
10. Method according to one of claims 1 to 9, characterized in that the container (30) is first provided in an upright position and is turned upside down before the cutting process.
11. Method according to one of claims 1 to 10, characterized in that the container (30) is rotated into the upright position after the cutting process.
12. Extrusion-blown container with an internal thread (20), characterized in that the internal thread (20) is manufactured by a machining process, in particular is cut, preferably produced in a process according to one of claims 1 to 11.
13. Device (100) for producing an internal thread (20), in particular in a method according to one of claims 1 to 11, in a container (30), in particular in a container (30) according to claim 12, comprising a feed device (101) for feeding containers (30), a holding device (60) for holding a container (30) in a form-fitting manner, a Device for cutting a thread, in particular a thread cutter (20), and a suction device (50) for sucking away chips (21) produced by a cutting process.
14. Device (100) according to claim 13, characterized in that the device (100) has a rotating device for rotating the containers (30) overhead before the cutting process.
15. Device (100) according to claim 13 or 14, characterized in that the device (100) has a rotating device for rotating the containers (30) overhead after the cutting process.