Transport pin, transport pin arrangement and heating device

Abstract

The invention relates to a transport pin for a heating device in a blow molding machine, having a head portion (2) contiguous with a shaft portion (1), and the head portion (2) has at least one holding surface (6) for clamping-contacting containers. According to the invention, the head portion (2) has an all-around closed surface (8).

Description

[0001] Transport mandrel, transport mandrel arrangement and heating device

[0002] The present invention relates to a transport mandrel for a heating device in a blow molding machine with a head section adjacent to a shaft section, wherein the head section has at least one holding surface for clamping containers.

[0003] The invention relates in particular to blow molding machines used in the beverage industry. In this respect, blow molding machines are used to form beverage containers, especially beverage bottles, from preforms, which are generally also referred to as preforms. It is understood that these preforms are made, in particular, of a plastic, e.g., polyethylene terephthalate (PET), so that they can be easily plastically formed during the blow molding process in the blow molding machine.

[0004] Before the actual blow molding, the preforms are typically heated to a predetermined temperature, which enables plastic deformation. For this purpose, the preforms are guided along a conveyor belt in the heating device and heated by heating elements. For transport, the containers are placed on corresponding conveyor mandrels, which clamp the containers in place. After passing through the conveyor belt, the containers are then removed from the conveyor mandrels, for example, using grippers, and fed to the blow molding machine.

[0005] Both active clamping elements and passive clamping elements can be provided for the clamping arrangements, whereby passive clamping elements have the advantage that no separate drive has to be provided which enables clamping of the container or preform to the head section of the transport mandrel.

[0006] It is known from the prior art to achieve passive clamping by having several clamping elements act in the circumferential direction on circumferentially arranged rubber rings, whereby a certain radial play can be achieved by the elasticity of the rubber rings, which is sufficient on the one hand to be able to accommodate the preforms and on the other hand to be able to apply a sufficiently large clamping force for transport.

[0007] Such a principle has proven fundamentally effective. However, the head section of the transport mandrels is particularly subject to contamination and soiling during operation. For example, rubber debris can settle in the individual recesses over time and thereby contaminate the containers. At the same time, it is often desired to produce the containers germ-free, so that in addition to heating, they are also sterilized with sterilization media, particularly hydrogen peroxide (H2O2). The rubber rings in particular have only limited resistance to a variety of cleaning and sterilization media, so that the transport domes must be cleaned at predefined intervals, and at the same time, the maintenance of individual components is very complex.

[0008] Against this background, the invention is based on the object of providing a transport dome which is easier to clean in terms of its design and is characterized by a lower maintenance design.

[0009] This object is achieved by a transport dome according to claim 1. The invention further relates to a transport dome arrangement according to claim 14 and a heating device according to claim 15.

[0010] Accordingly, it is provided that the head section has a circumferentially closed surface. The surface is therefore designed without any kind of perforations, so that the holding surfaces are also formed by the circumferentially closed surface. The closed surface prevents contaminants, in particular small particles, from penetrating the head section of the transport dome. In such a case, cleaning is only possible under very difficult conditions and with complex measures. In particular, at least the head section of the transport dome usually has to be disassembled to enable complete cleaning. Due to the closed surface, a particularly advantageous transport dome is created, particularly from a hygienic point of view, which can be cleaned using simple means. According to a preferred embodiment, the circumferentially closed surface is made of a single material.Accordingly, the entire surrounding surface is made of a single material. This ensures that transitions between different materials are also eliminated, although it is precisely at these transitions that cracks or gaps can form over time, which in turn is disadvantageous from a hygienic perspective. The material of the closed surface can be made, for example, of a metal or a plastic, particularly an elastomer.

[0011] A further development of the invention provides that the at least one holding surface is formed on a projecting section of the circumferentially closed surface. The projecting sections form discrete points of the head section, which, in combination with a certain elasticity, retract slightly when a container is inserted and simultaneously exert a sufficient clamping force on the inner walls of the container to hold the corresponding container to the transport dome during transport. The clamping force is transmitted via the holding surfaces, which form an outer surface of the projecting section.

[0012] According to a further development of the invention, the projecting section is surrounded by a groove formed in the circumferentially closed surface. Such a groove makes it possible to determine the elasticity of the projecting sections and thus also of the holding surfaces. This configuration is particularly suitable when the circumferentially closed surface is not formed on a solid body but on a hollow body made of a thin-walled material. In such a case, the elastic behavior of the projecting sections and thus also the clamping force via the holding surfaces can be determined by incorporating a corresponding groove and thus by designing the geometric shape.

[0013] In an alternative embodiment, the projecting section is at least partially surrounded by a spring section which is designed with a different, in particular smaller, wall thickness than the projecting section. This also makes it possible to set a specific elasticity and thus clamping force. The groove preferably has a width of less than 15 mm, preferably less than 10 mm. In particular, the width of the groove is between 3 and 15 mm, particularly preferably between 5 and 10 mm. The depth of the groove is preferably less than 10 mm, preferably less than 8 mm. In particular, the depth of the groove is between 1 and 10 mm, preferably between 3 and 8 mm.

[0014] As already explained above, a preferred embodiment of the invention provides that the circumferentially closed surface is formed on a hollow body. According to such an embodiment, the circumferentially closed surface is formed by the outer surface of a sleeve, which at least partially surrounds an inner core of the head section. Accordingly, it may be sufficient if the sleeve only encloses a section which is responsible for ensuring that the sleeve can be held to the other components of the transport mandrel. Otherwise, the head section is predominantly a hollow body, so that the elasticity of such a hollow body can be used in a preferred manner, especially when incorporating protruding sections. According to such an embodiment, the sleeve is preferably formed from a metal sheet. The thickness is preferably between 0.5 and 3 mm.

[0015] However, a further embodiment also provides for the sleeve to be made of a plastic, in particular an elastomer. Such a design is particularly useful when the sleeve encloses the core at least in the area of ​​the projecting sections, in which case the elasticity of the holding surfaces is primarily based on the elasticity of the material. Such a design is also possible if no projecting sections are provided in the circumferentially closed surface. In such a case, clamping at the holding surfaces would rely solely on the elasticity of the material.

[0016] A further development of the invention further provides that a driven actuating element is assigned to the at least one holding surface. Using such an actuating element, it is possible to configure the transport mandrel with an active clamping mechanism. This actuating element acts on the holding surfaces and transfers them into a clamping position for clamping, in which the holding surfaces are moved outward. Thus, the clamping is not based on the elasticity of the material or the geometric design. Rather, clamping is actively achieved by positioning an actuating element.

[0017] According to a further development of the invention, the head section has at least two, preferably at least three, retaining surfaces. A particularly preferred embodiment provides a total of four retaining surfaces. Furthermore, the retaining surfaces are preferably arranged equidistantly in the circumferential direction. According to such an embodiment, it can further be provided that each of the retaining surfaces is formed on a projecting portion.

[0018] Although the design of the head sections is not limited to a specific geometric shape, a preferred embodiment provides that the head section and also the circumferentially closed surface are circular.

[0019] The invention further relates to a transport dome arrangement according to claim 14, comprising a transport mandrel and a container, in particular a plastic preform, which is clamped to the head portion of the transport mandrel. Clamping takes place at a mouth portion of the preform, which is typically formed on the surrounding walls with an external thread for receiving a closure cap. Located below the external thread is a retaining ring, which typically protrudes beyond the external thread. The preforms are therefore already preformed and, especially in the mouth portion, require no further processing within a blow molding machine. The head portion is then inserted into the mouth portion and clamps the preform to the inner walls of the mouth portion.

[0020] Furthermore, the invention also provides a heating device for a blow molding machine, comprising a plurality of transport mandrels according to the invention arranged continuously along a transport path and at least one heating element associated with the transport path. Such heating devices are generally known from the prior art, with the transmandrels directly adjoining one another along the transport path and guiding the containers or preforms along the at least one heating element. The containers are continuously heated and removed at the end of the transport path via a gripper.

[0021] To ensure the containers can be removed as easily as possible, the transport domes are designed to be liftable, at least in sections along the transport route. This allows the transport domes and thus also the containers arranged on them to be moved from an operating position to a removal position, allowing the grippers to easily grasp the containers without being hindered by the adjacent containers or transport domes.

[0022] The invention is explained in more detail below using an exemplary embodiment. The figures show:

[0023] Fig. 1 a transport dome according to the prior art

[0024] Fig. 2 the head section of the transport dome according to Fig. 1

[0025] Fig. 3 the head section of a transport dome according to the invention in an isometric view

[0026] Fig. 4 the transport dome according to Fig. 3 in a sectional view

[0027] Fig. 1 shows the basic structure of a prior art transport dome. Such a transport dome is typically used, for example, in a heating device for a blow molding machine and has a shaft section 1 and a head section 2 adjacent to the shaft section 1. The transport dome can be attached to the heating device in a connecting section 3 opposite the head section 2, with the transport dome being attached via a spring 4. The precise design of the head section 2 is particularly clear when viewed in conjunction with Fig. 2. Accordingly, clamping elements 5 are provided which have holding surfaces 6 projecting radially outwards.

[0028] With the help of the holding surfaces 6, it is now possible to act radially inward on the walls of a container, e.g., a preform, in order to clamp the container to the transport dome. For this purpose, the clamping elements 5 act on two rubber rings 7 spaced apart in the axial direction, which accordingly exhibit a certain elasticity, so that the clamping elements 5 with the holding surfaces 6 can deflect slightly in the radial direction when inserted into the container, while simultaneously exerting a clamping force on the container.

[0029] However, Fig. 2 also shows that such a design involves numerous indentations and perforations in which dirt particles or other contaminants can accumulate, making cleaning extremely difficult. In particular, it is necessary to almost completely disassemble the head section 2 of the transport mandrel to enable perfect cleaning from a hygienic point of view.

[0030] Against this background, Figs. 3 and 4 show a head section 2 according to the invention, wherein the head section 2 has a circumferentially closed surface 8, wherein the holding surfaces 6 are also formed as part of the circumferentially closed surface 8. Such an inventive design consequently provides no perforations in the surface 8, thus enabling significantly easier cleaning.

[0031] According to the embodiment shown in Figs. 3 and 4, the circumferentially closed surface is formed on a sleeve 9 made of thin-walled metal sheet, wherein projecting sections 10 are embossed into the sleeve 9 and wherein the holding surfaces 6 are in turn formed on the radially projecting sections 10.

[0032] Furthermore, the projecting sections 10 are surrounded by a groove 11. Due to the structural design made of a single, thin-walled metal sheet, the projecting section 10 and the holding surfaces 6 are thus provided with sufficient elasticity, which allows a sufficient clamping force to be applied to the containers, analogous to the previously known design according to Fig. 2.

[0033] Analogous to the embodiment of Fig. 2, a total of four holding surfaces 6 are provided according to Fig. 3 and Fig. 4, each of which is formed on a projecting section 6. In principle, the head section 2 shown in Fig. 3 and 4 is merely an exemplary embodiment. Deviating from this, embodiments are also conceivable in which the sleeve 9 is formed from a plastic, e.g. an elastomer, and rests against an internal core. Furthermore, for example, an adjusting element can also be assigned to each of the projecting sections 6, via which an active clamping is then effected.

Claims

Claims: Transport mandrel for a heating device in a blow molding machine with a head section (2) adjoining a shaft section (1), wherein the head section (2) has at least one retaining surface (6) for clamping containers, characterized in that the head section (2) has a circumferentially closed surface (8). Transport mandrel according to claim 1, characterized in that the circumferentially closed surface (8) is formed of a single material. Transport mandrel according to claim 1 or 2, characterized in that the at least one retaining surface (6) is formed on a projecting section (10) of the circumferentially closed surface (8). Transport mandrel according to claim 3, characterized in that the projecting section (10) is surrounded by a groove (11) formed in the circumferentially closed surface (8).Transport mandrel according to claim 4, characterized in that the groove (11) has a width between 3 and 15 mm. Transport mandrel according to claim 4 or 5, characterized in that the groove (11) has a depth between 1 and 10 mm.

7. Transport mandrel according to one of claims 3 to 6, characterized in that the projecting section (10) is at least partially surrounded by a spring section which has a different wall thickness compared to the projecting section (10).

8. Transport mandrel according to one of claims 1 to 7, characterized in that the continuously closed surface (8) is the outer surface of a sleeve (9) which at least partially surrounds an inner core of the head section (2).

9. Transport mandrel according to claim 8, characterized in that the sleeve (9) is made of a metal sheet or of a plastic.

10. Transport mandrel according to claim 9, characterized in that the metal sheet has a thickness between 0.5 and 3 mm.

11. Transport mandrel according to one of claims 1 to 10, characterized in that a driven actuating element is assigned to the at least one holding surface (6).

12. Transport mandrel according to one of claims 1 to 11, characterized in that the head section (2) has at least two, preferably at least three retaining surfaces (6).

13. Transport mandrel according to one of claims 1 to 12, characterized in that the head section (2) is cylindrical.

14. Transport mandrel arrangement comprising a transport mandrel according to one of claims 1 to 13 and a container, in particular a preform made of plastic, which is clamped to the head section (2) of the transport mandrel. Heating device for a blow molding machine with a plurality of continuously arranged transport domes along a transport path according to any one of claims 1 to 13 and at least one heating element assigned to the transport path. Heating device according to claim 15, characterized in that the transport domes are arranged to be movable at least section by section along the transport path.

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