Device for extrusion blow moulding and method for producing a blow moulded part

Abstract

The invention relates to a device (50) for the extrusion blow moulding of a blow moulded part, having an extrusion nozzle (82) for extruding a tubular preform, a multi-part tool that has a cavity for arranging the preform, wherein the cavity opens into a first neck region of the tool, and a first mandrel (84) for arranging on and / or in the first neck region, wherein the first mandrel is in multiple parts along a central first mandrel axis and has a first base part remote from the cavity and a first neck part close to the cavity, wherein the first base part and the first neck part are releasably connected to one another via a first connecting device. The invention also relates to a method for producing a blow moulded part.

Description

[0001] Title: Device for extrusion blow molding and method for producing a blow molded part

[0002] Description

[0003] The invention relates to a device for extrusion blow molding of a blow molded part, comprising an extrusion die for extruding a tubular preform, a multi-part tool having a cavity for arranging the preform, the cavity opening at a first neck region of the tool, and a first mandrel for arrangement on and / or in the first neck region. The invention further relates to a method for

[0004] Production of a blow-molded part. Devices known from the prior art for extrusion blow molding of a blow-molded part have a first mandrel for arrangement on and / or in the first neck region of the mold. The first mandrel can have various functions, for example, a molding function of a surface of the first mandrel, a holding function for an insert, or a supply of blowing air. Due to the contact of the first mandrel with the mold and / or due to the spatial proximity of the first mandrel to the cavity of the mold, the first mandrel is exposed to increased heat input. This heat input is caused by the preform, which consists of a hot plastic material, and – after blow molding of the preform – also by the initially still hot blow-molded part. Another, particularly strong heat source is the extrusion die, which is arranged adjacent to the mold.

[0005] The heat input discussed above results in the heating of the first mandrel. Excessive heating of the first mandrel can have adverse consequences for the process stability of the blow molding process. For example, it is possible that the plastic material of the blow molded part adjacent to the first mandrel will overheat or cool too slowly, so that the first neck section of the blow molded part adjacent to the first mandrel will still be too hot after the mold is opened and therefore unstable, and will be deformed or damaged when the first mandrel is separated from the blow molded part.

[0006] A relatively simple way to mitigate the aforementioned problems is to allow a resting period after the production of a first blow-molded part and before the production of a second, which serves to cool down components of the device. However, such a resting period is undesirable for economic reasons. Furthermore, it is possible to cool parts of the device with water cooling. However, such water cooling requires considerable design effort.

[0007] Based on this, the present invention aims to provide a device and a method that simplify the efficient production of a blow-molded part.

[0008] This problem is solved according to the invention in an extrusion blow molding device of the type mentioned above by the fact that the first mandrel is multi-part along a central first mandrel axis and has a first base part far from the cavity and a first neck part close to the cavity, wherein the first base part and the first neck part are detachably connected to each other via a first connecting device.

[0009] The device according to the invention comprises a first mandrel with a first base part located away from the cavity. In its state connected to the first neck part located near the cavity, this base part has a holding function for the first neck part. The first neck part is arranged on or in the first neck region of the tool, at least during a blow forming operation of the preform, and can have various functions, which will be explained below.

[0010] According to the invention, it was recognized that it is advantageous to divide the first mandrel into a first base part and a first neck part and to detachably connect these parts to one another by means of a first connecting device. This has the following advantages:

[0011] The separability of the first neck section from the first base section allows for the use of different, interchangeable first neck sections while using the same first base section. This prevents excessive heating of the cavity-adjacent section of the first mandrel, enabling the device to be used continuously for the production of blow-molded parts without requiring rest periods or cooling phases.

[0012] The separability of the first neck section from the first base section allows the first neck section – after the blow molding process and opening of the tool – to remain attached to the blow mold and serve as a cooling jig until the blow mold is sufficiently dimensionally stable to allow the first neck section to be separated. This cooling process preferably takes place in a state where the first neck section is separated from the first base section and thus from the device, so that the device – using an additional first neck section and the same first base section – can be used to produce another blow mold while the first one is cooling.

[0013] Temporarily retaining the first neck section on the blow molded part is also advantageous if the first neck section serves to hold an insert, usually metallic, that is to be placed on or in the blow molded part. After its formation, the blow molded part—after opening the mold—can be removed from the mold together with the first neck section and handled, processed, and / or cooled away from the extrusion blow molding machine. This makes it possible to separate the first neck section from the insert outside the machine in such a way that any release forces act only on the insert and the first neck section, but not on the plastic material of the blow molded part. In this way, even a blow molded part that is not yet fully dimensionally stable can be protected from damage.The thermal advantages achievable through interchangeable first neck parts, as already explained above, also apply here. Furthermore, a cooling period can be provided to stabilize the blow-molded part, particularly before separating the first neck part from the insert and / or before other post-processing steps, with the device being available concurrently with the production of another blow-molded part.

[0014] Finally, the separability of the first neck section from the first base section and the temporary retention of the first neck section on a freshly produced blow molded part offer the advantage that the travel distance of the first mandrel can be shortened by the length of the first neck section along the central axis of the first mandrel. This allows a device to be used to produce comparatively larger blow molded parts within a given installation space.

[0015] Further advantageous embodiments of the device are described below. Preferably, the first connecting device comprises a

[0016] Coupling device, in particular a quick-coupling device. This enables quick and easy connection of the first base part and the first neck part, as well as quick and easy detachment of the first neck part from the first base part.

[0017] It is further preferred if the device comprises a first control unit for controlling the connection state of the first connection device, in particular a first control unit for remote control of the connection state of the first connection device. In this way, the connection state of the first connection device can be controlled in a simple manner, in particular without requiring manual intervention and manual handling of the connection device.

[0018] As mentioned at the beginning, the first neck section can have various functions. One preferred option is for the first neck section to have an outer surface designed to mold a first inner surface section of the blow molded part. In this way, a blow molded part can be produced whose outer surfaces are created by molding against the cavity of the tool, whereby an inner surface section of a neck section of the blow molded part can be molded by the outer surface of the first neck section.

[0019] Another function of the first neck section can be to hold a first insert, which is detachably connected to or attached to the first neck section, wherein the first insert is designed to remain attached to and / or within the blow molded part. The insert is, in particular, an insert made of a metallic material. The insert can also be referred to as an "insert" and typically serves to define an opening in the blow molded part, which is used for filling with a gas or liquid. As a component of the blow molded part, the first insert forms a connection element, in particular for connecting a boss, a valve, a filling fitting, or a closure.

[0020] Advantageously, the device comprises an additional first neck section located near the cavity, which can be detachably connected to the first base section in place of the first neck section. This opens up the possibility that the first neck section remains attached to a first blow molding part, while the additional first neck section located near the cavity is connected to the base section and used for the production of a second blow molding part.

[0021] It is possible for the first mandrel to be arranged on the side of the tool facing the extrusion die, or on the side of the tool facing away from the extrusion die. The closer the first mandrel is arranged to the extrusion die, the greater the advantage of the invention that excessive heating of a cavity-adjacent section of the first mandrel can be avoided. This advantage of the invention is particularly significant when the first mandrel is arranged at the extrusion die.

[0022] It is possible that the first mandrel has a first neck section with an outer surface for molding a first inner surface section of the blow molded part and / or is designed as a holding mandrel for an insert and does not simultaneously have the function of introducing blowing air into a cavity enclosed by the preform. It is also possible that the first mandrel additionally or alternatively has a first blowing channel for introducing blowing air into a cavity enclosed by the preform.

[0023] Further preferred embodiments of the device relate to dependent claims 9 to 16. These embodiments serve to manufacture blow-molded parts which have two neck sections, preferably arranged at opposite ends of the blow-molded part. A second mandrel, which is also multi-part and has the features of dependent claim 9, is used to manufacture such a blow-molded part. This results in the advantages discussed above with reference to the multi-part first mandrel also being realized for the second mandrel.

[0024] Regarding the embodiments and advantages of the features of dependent claims 10 to 16, reference is made to the preceding description, in particular to the features of dependent claims 2 to 8, in order to avoid repetition.

[0025] It is further noted that a second control device for controlling a connection state of the second connection device of the second mandrel may advantageously be the first control device of the first connection device.

[0026] It is further added that the first thorn and the second

[0027] The mandrels are advantageously arranged on opposite sides of the tool, and it is further preferred that the first mandrel axis and the second mandrel axis are aligned with each other, in particular along a central tool axis which corresponds to a central blow molding axis.

[0028] Optionally, the second mandrel has a second blowing channel for introducing blown air into a cavity enclosed by the preform. To simplify the design of the device, it is preferred that only one of the two mandrels has a blowing channel. Therefore, the feature of a "second" blowing channel is solely due to its association with the second mandrel and not to the necessity of having two blowing channels simultaneously.

[0029] The problem mentioned at the outset is also solved by a method with the features of claim 17.

[0030] With reference to process steps d) and e), it is understood that these process steps can be carried out sequentially, for example, if the tubular preform is to be extruded outside an open tool and only subsequently arranged in the open tool. However, it is also possible to carry out process steps d) and e) simultaneously by extruding the tubular preform into a space enclosed by the open tool.

[0031] The optional process step 1), namely the cooling of the first blow molded part, can, for example, be accompanied by active cooling, such as by the supply of cooled air. Process step 1 can additionally or alternatively also be accompanied by a waiting period during which the first blow molded part cools down by a predefinable temperature difference.

[0032] Regarding the embodiments and advantages of the method claims 18 to 20, reference is made to the preceding description of the device according to the invention, in particular to the features of dependent claims 4 to 6.

[0033] When using an additional first neck section, it is preferred that this section be connected to the first base section, at least during the cooling of the first blow molded part and / or during the separation of the first neck section from the first blow molded part and / or during post-processing of the first blow molded part. This makes it possible to use the first base section and the additional first neck section to produce another blow molded part while the first blow molded part is already outside the tool. In other words, the use of an additional first neck section makes it possible to avoid unproductive downtime.

[0034] Corresponding advantages and embodiments also arise for methods according to dependent claims 22 to 26. These relate to the use of a multi-part second mandrel. Reference is also made in this regard to the corresponding explanation of the device according to the invention.

[0035] The blow-molded part is, in particular, a gas-tight liner for a high-pressure vessel. The liner is made of a plastic material and has at least one first neck section, which is preferably provided with a metallic insert. The insert serves to attach a connection element, for example, a boss, a valve, a filling fitting, or a closure.

[0036] Further features and advantages of the invention are the subject of the following description of preferred embodiments.

[0037] The drawing shows:

[0038] Fig. 1 a perspective view of a first

[0039] From the execution form of a blow-molded part in the form of a liner for a high-pressure vessel;

[0040] Fig. 2 shows a cutaway view of the blow-molded part according to Fig. 1;

[0041] Figs. 3a and 3b show a side view and a cutaway view of a device for extrusion blow molding of a blow molded part according to Fig. 1, wherein the device comprises a first mandrel and a second mandrel;

[0042] Figs. 4a to 4c are sectional views of the first mandrel;

[0043] Figs. 5a to 5c are sectional views of the second mandrel;

[0044] Figures 6a and 6b show views corresponding to Figures 3a and 3b with an extruded preform; Figures 7a and 7b to 12a and 12b show views corresponding to Figures 6a and 6b of subsequent process steps;

[0045] Fig. 13 shows a perspective view of the blow molded part according to Fig. 1, with a first neck part and with a first insert part;

[0046] Fig. 14 shows a view corresponding to Fig. 13 with tools attached to the first neck part and the first insert part, respectively;

[0047] Fig. 15 shows a view corresponding to Fig. 13, with the first neck part removed from the first insert part;

[0048] Fig. 16 shows a view corresponding to Fig. 13 with the first neck part detached;

[0049] Fig. 17 shows a perspective view of another embodiment of a blow-molded part in the form of a liner for a high-pressure vessel;

[0050] Fig. 18 shows a cutaway view of the blow molded part according to Fig. 17;

[0051] Figs. 19a and 19b are sectional views of a first mandrel for the production of a blow-molded part according to Fig. 17;

[0052] Figs. 20a and 20b are sectional views of a second mandrel for producing a blow-molded part according to Fig. 17; and Figs. 21a and 21b are corresponding to Fig. 8a.

[0053] Side view and a cutaway view corresponding to Figure 8b of a device for extrusion blow molding of a blow molded part according to Fig. 17.

[0054] A first embodiment of a blow-molded part is shown in Figures 1 and 2 and is designated there in its entirety by reference numeral 10. The blow-molded part 10 has a blow-molded body 12 made of a plastic material, which extends along a central blow-molded axis 14 and defines a storage space 16 for storing gas, in particular pressurized gas.

[0055] The blow-molded part 10 shown in Figures 1 and 2 is also referred to as an inner shell or "liner" and serves for gas sealing. Such a liner is part of a high-pressure vessel which—in addition to the representation according to Figures 1 and 2—has reinforcement, in particular made of a fiber-reinforced plastic material, which surrounds the blow-molded body 12.

[0056] The blow molded part 12 has a cylindrical section 18 concentric with the central blow molding axis 14 and furthermore a first end section 20 and a second end section 22. The end sections 20 and 22 are arranged on opposite sides of the blow molded part 10 with respect to the cylindrical section 18 and along the central blow molding axis 14 and can, for example, be hemispherical, dome-shaped or in the form of a dished end. The cylindrical section 18 and the end sections 20 and 22 together define the storage space 16.

[0057] The first end section 20 has a first neck section 24; the second end section 22 has a second neck section 26. In the region of the respective neck sections 24 and 26, blow molding openings are formed, namely a first blow molding opening 28 and a second blow molding opening 30. The blow molding openings 28 and 30 are arranged concentrically to the central blow molding axis 14.

[0058] The neck sections 24 and 26 each have a funnel section that tapers from the outside towards the storage space 16, namely a first funnel section 32 and a second funnel section 34.

[0059] The funnel sections 32, 34 each open onto a disc-shaped section, namely a first disc-shaped section 36 and a second disc-shaped section 38.

[0060] Each of the disc-shaped sections 36, 38 has an insert made of a metallic material, namely a first insert 40 and a second insert 42. The inserts serve to fasten a connection element not shown in the drawing, in particular a boss, a valve, a filling fitting or a closure.

[0061] A design form of a device for

[0062] The extrusion blow molding of a blow molded part 10 is designated by reference numeral 50 in the drawing (see, for example, Figure 3a).

[0063] The device 50 is mounted on a base 52 and comprises a machine bed 54. The machine bed 54 serves to arrange tool holders, namely a first tool holder 56 and a second tool holder 58. The tool holders 56, 58 are arranged on opposite sides of a vertically oriented parting plane 60.

[0064] The tool holders 56, 58 are each movable along a traversing axis, namely a first traversing axis 62 and a second traversing axis 64, relative to the machine bed 54, so that the tool halves 56 and 58 can each be moved in the direction towards the parting plane 60 and in the opposite direction.

[0065] The tool holders 56, 58 each serve to arrange one tool half, namely a first tool half 66 and a second tool half 68.

[0066] For the arrangement and handling of the first tool half 66, a first clamping plate 70 is arranged on the first tool holder 56. For the arrangement and handling of the second tool half 68, a second clamping plate 72 is arranged on the second tool holder 58.

[0067] The tool halves 66 and 68 together form a multi-part tool 74, see, for example, Figure 8a. The tool halves 66 and 68 each have several tool parts, namely a first end part 76, a second end part 78, and a middle part 80.

[0068] The first end parts 76 are assigned to the first end section 20 of the blow-molded part 10. The second end parts 78 are assigned to the second end section 22 of the blow-molded part 10. The middle parts 80 are assigned to the cylindrical section 18 of the blow-molded part 10.

[0069] The end parts 76 and 78 of each tool half 66, 68 are each movable relative to the middle part 80 of the same tool half 66, 68 at the respective

[0070] held on clamping plate 70, 72. In this way, the end parts 76, 78 can be arranged spaced apart from the middle part 80 (see Figure 3a) or in contact with the respective middle part 80 (see, for example, Figure 8a).

[0071] The device 50 also includes an extrusion nozzle 82, which is arranged above the tool 74.

[0072] Furthermore, the device 50 comprises a first mandrel 40, which is arranged in a lower region of the tool 74, and a second mandrel 86, which is arranged in an upper region of the tool 74. The second mandrel 86 is arranged on the extrusion die 82.

[0073] The extrusion die 82 has a head 88 and a nozzle 90, the nozzle 90 being movable relative to the head 88 between a closed position (see Figure 3b) and an open position (see Figure 6b). The second mandrel 86 is connected to the nozzle 90 of the extrusion die 82.

[0074] The first mandrel 84 is connected to a mandrel holder 92, which has a blow air connection 94 for supplying the first mandrel 84 with blow air and a control connection 96, which communicates with a first control device 98 (see Figure 3b).

[0075] The construction of the first mandrel 84 is described below with reference to figures 4a to 4c.

[0076] The first mandrel 84 extends along a central first mandrel axis 100 and is multi-part. A first base part 102 serves for connection with the mandrel holder 92. The first base part 102 is arranged further away from a cavity 154 (see Figure 7b) of the tool 74 than a first neck part 104 of the first mandrel 84.

[0077] The first base part 102 and the first neck part 104 can be repeatedly and detachably connected to each other by means of a first connecting device 106.

[0078] The first basic part 102 has a first fastening section 108 for attachment to the mandrel holder 92. The first basic part 102 further has a hollow cylindrical section 110 which defines an interior 112.

[0079] A holder 114 is arranged in the interior space 112. The holder 114 has openings 116 for the passage of compressed air. The holder 114 serves to hold a first connecting section 118 of the first connecting device.

[0080] 106. The first connecting section 118, for example, includes a recording room 120.

[0081] The first neck section 104 comprises a hollow cylinder 122 extending along the first mandrel axis 100. At one end facing the first base section 102, a second holder 124 is arranged on the hollow cylinder 112, which also has openings 126 for the passage of blown air. The second holder 124 serves to hold a second connecting section 128 of the first connecting device 106. The second connecting section 128 includes, for example, a pin 130.

[0082] The hollow cylinder 122 has a fastening section 132 at its end opposite the second connecting section 128 for the detachable fastening of the first insert 40. The fastening section 132 is, for example, stub-shaped and extends, for example, to a stop 134, which defines a position of the first insert 40 along the central first mandrel axis 100. The first insert 40 is, for example, force-fitted onto the fastening section 132 or preferably screwed to the fastening section 132.

[0083] The first connecting device 106 comprises a controllable locking element 136, which is movable between a release position (see Figures 4a and 4b) and a locking position (see Figure 4c). The locking element 136 can be pressurized with compressed air via a control channel 138. The control channel 138 is supplied by a control line 140, which is fluidly connected to the control port 96 of the mandrel holder 92 (see Figure 3b).

[0084] Starting from a separate state of the first base part 102 and the first neck part 104, a connection between the first base part 102 and the first neck part 104 is established by moving the first neck part 104 along the first mandrel axis 100 in the direction of the first base part 102, so that the second connecting section 128 is received in the first connecting section 118 (corresponds to a transition from Figure 4a to Figure 4b).

[0085] Figure 4b shows the first base part 102 and the first neck part 104 in a joined, yet still detachable state. To lock the first neck part 104 to the first base part 102, the locking element 136 is pressurized with compressed air via the control connection 96, the control line 140 and the control channel 138, so that the locking element 136 is displaced radially inwards and locked with a locking element receptacle 142 of the second connecting section 128.

[0086] In the state shown in Figure 4c, the first neck part 104 is connected to and locked with the first base part 102. This locking is released by stopping the pressure applied to the locking element 136, so that the locking element 136 is again freely movable, in particular radially outwards.

[0087] The first mandrel 84 also has a first blowing channel 144 .

[0088] The first blow channel 144 extends from an inlet 146, which communicates with the blow air connection 94 of the mandrel holder 92 (see Figure 3b), to an outlet 148, from which blow air can be supplied into a cavity 150, which is enclosed by a preform 152, see Figure 6b.

[0089] The passage openings 116 and 126 of the first mandrel 84 serve to allow blown air to be supplied through the interior 112 of the first base part 102.

[0090] The construction of the second mandrel 86 is described below with reference to figures 5a to 5c.

[0091] The second mandrel 86 extends along a central second mandrel axis 200 and is multi-part. A second base part 202 serves to connect it to the nozzle part 90 of the extrusion die 82. The second base part 202 is arranged further away from the cavity 156 (see Figure 7b) of the tool 74 than a second neck part 204 of the second mandrel 86.

[0092] The second base part 202 and the second neck part 204 can be repeatedly and detachably connected to each other by means of a second connecting device 206.

[0093] The second basic part 202 has a second mounting section 208 for attachment to the nozzle part 90 of the extrusion nozzle 82. The second basic part 202 further has a hollow cylindrical section 210 which defines an interior 212.

[0094] A holder 214 is arranged in the interior space 212. The holder

[0095] 214 has openings 216 for the passage of blown air. The holder 214 serves to hold a first connecting section 218 of the second connecting device 206. The first connecting section 218 includes, for example, a receiving chamber 220.

[0096] The second neck section 204 comprises a hollow cylinder 222 extending along the second mandrel axis 200. At one end facing the second base section 202, a second holder 224 is arranged on the hollow cylinder 212, which also has openings 226 for the passage of blown air. The second holder 224 serves to hold a second connecting section 228 of the second connecting device 206. The second connecting section 228 includes, for example, a pin 230.

[0097] The hollow cylinder 222 has a fastening section 232 at its end opposite the second connecting section 228 for the detachable fastening of the second insert 42. The fastening section 232 is, for example, stub-shaped and extends, for example, to a stop 234, which defines a position of the second insert 42 along the central second mandrel axis 200. The second insert 42 is, for example, force-fitted onto the fastening section 232 or preferably screwed to the fastening section 232.

[0098] The second connecting device 206 comprises a controllable locking element 236, which is movable between a release position (see Figures 5a and 5b) and a locking position (see Figure 5c). The locking element 236 can be actuated with compressed air via a control channel 238. The control channel 238 is supplied by a control line 240, which communicates with a second control device or with the first control device 98 (see Figure 3b).

[0099] Starting from a separate state of the second base part 202 and the second neck part 204, a connection between the second base part 202 and the second neck part 204 is established by moving the second neck part 204 along the second mandrel axis 200 in the direction of the second base part 202, so that the second connecting section 228 is received in the first connecting section 218 (corresponds to a transition from Figure 5a to Figure 5b).

[0100] Figure 5b shows the second base part 202 and the second neck part 204 in a joined, yet still detachable state. To lock the second neck part 204 to the second base part 202, the locking element 236 is pressurized with compressed air via the control line 240 and the control channel 238, so that the locking element 236 is displaced radially inwards and locked with a locking element receptacle 242 of the second connecting section 128.

[0101] In the state shown in Figure 5c, the second neck part 204 is connected to and locked with the second base part 202. This lock is released by stopping the pressurization of the locking element 236, so that the locking element 236 is again freely movable, in particular radially outwards. The second mandrel 86 also has a second blow channel 244. The second blow channel 244 extends from an inlet 246, which communicates with a blow air connection (not shown in the drawing) if required, to an outlet 248, from which blow air can be supplied into the cavity 150, which is bounded by the preform 152 (see Figure 6b).

[0102] The passage openings 216 and 226 of the second mandrel 86 serve to allow blowing air to be supplied through the interior 212 of the second basic part 202.

[0103] The tool parts 76, 78 and 80 of the tool 74 each delimit partial sections of the cavity 154, cf. Figure 7b. The first end parts 76 delimit a first partial section 156 of the cavity 154. The second end parts 78 delimit a second partial section 158 of the cavity 154. The middle parts 80 delimit an intermediate section 160 of the cavity 154.

[0104] The first subsection 156 of the cavity 154 serves to mold the first end section 20 of the blow mold 12. The second subsection 158 of the cavity 154 serves to mold the second end section 22 of the blow mold 12. The intermediate section 160 of the cavity 154 serves to mold the cylindrical section 18 of the blow mold 12.

[0105] The first section 156 of the cavity 154 opens onto a first neck region 162 of the first end parts 76 of the tool 74. The second section 158 of the cavity 154 opens onto a second neck region 164 of the second end parts 78 of the tool 74. The first neck region 162 forms a transition between the cavity 154 and a surrounding region 166 of the tool 74, in particular the first end parts 76. The second neck region 164 forms a transition between the cavity 154 and a surrounding region 168 of the tool 74, in particular the second end parts 78.

[0106] As part of the first neck area 162, the first end parts 76 of the tool 74 have a first parting edge 170.

[0107] As part of the second neck area 164, the second end parts 78 of the tool 74 have a second parting edge 172 .

[0108] The parting lines 170 and 172 form a narrowing of the respective neck areas 162, 164, by means of which material sections of the extruded preform 102 can be cut through.

[0109] Starting from a state of the device 50 according to Figures 3a and 3b, the production of a blow molded part 10 is described below with reference to Figures 6a, 6b to 12a, 12b .

[0110] In an initial state as shown in Figure 6a, the tool halves 66, 68 are separated from each other. Furthermore, the tool parts 76, 78, 80 are spaced apart from each other, each corresponding to a tool half 66, 68. In this state, the nozzle part 90 is lifted from the head part 88 of the extrusion die 82, and a tubular preform 152 is extruded. The preform 152 aligns itself according to gravity and initially surrounds only the second mandrel 86, and with increasing extrusion time also a portion of the length of the first mandrel 84. The extrusion of the preform 152 is stopped when a lower boundary 174 of the preform 152 is adjacent to the mandrel holder 92.

[0111] Starting from the open state of the tool halves 66 and 68, they are closed by moving them towards the parting line 60 until they touch, see Figure 7a. In this state, parts 76, 78, and 80 of each tool half 66 and 68 are still spaced apart. The first mandrel 84 passes through the first neck section 162. The second mandrel 86 passes through the second neck section 164.

[0112] The first separating edge 170 lies against an outer surface 176 of the first neck part 104, see Figure 4a.

[0113] The second separating edge 172 lies against an outer surface 276 of the second neck part 204, see Figure 5a.

[0114] In a state where parts 76, 78, 80 of the tool halves 66 and 68 are still spaced apart from each other, the insert parts 40, 42 are still spaced apart from the respective neck regions 162, 164. Starting from this state, parts 76, 78, 80 of the tool halves 66 and 68 are closed, see Figure 8a. With mandrels 84 and 86 fixed, closing the first end parts 76 and the second end parts 78 with the middle parts 80 causes the insert parts 40 and 42 – each including material of the preform 152 – to be arranged directly adjacent to the respective neck regions 162, 164, see Figure 8b. The closing of parts 76, 78, 80 of the tool halves 66, 68 results in the parting edges 170, 172 having excess

[0115] Separate material from the preform 152.

[0116] By supplying compressed air via the compressed air connection 94 into the cavity 150 of the preform 152, the preform 152 is formed – according to the geometry of the cavity 154. With the formation of the preform 152, a blow-molded part 10 is created, cf. Figure 9b.

[0117] To demold the blow-molded part 10, starting from a state according to Figure 8a and a completely closed tool 74, the parts 76, 78, 80 of each tool half 66, 68 are first spaced apart from each other, cf. Figure 9b. In this way, the first end parts 76 and the second end parts 78 are spaced apart from the respective end sections 20, 22 of the blow-molded body 12, so that funnel-shaped tool sections 178, 180 are spaced apart from the respective funnel sections 32, 34 of the blow-molded part 10 and are free for a subsequent opening of the tool halves 66 and 68.

[0118] Starting from the state of the device 50 according to Figures 9a and 9b, the tool halves 66 and 68 are opened so that the molded blow-molded part 10 is released. The blow-molded part 10 is initially still fixed to the mandrels 84 and 86, with the first mandrel 84 being connected to the mandrel holder 92 and the second mandrel 86 being connected to the extrusion die 82.

[0119] Starting from the state described above in Figure 10b, the first connecting device 106 is actuated, thus releasing the connection between the first base part 102 and the first neck part 104. The first base part 102 can then be separated from the first by moving the mandrel holder 92.

[0120] Neck part 104 is removed, see Figure 11b. The first neck part 104 initially remains attached to the first blow mold part 10.

[0121] Subsequently, by actuating the second connecting device 206, the connection between the second neck part 204 and the second base part 202 of the second mandrel 86 can be released. After releasing this connection, the second base part 202 and the second neck part 204 are separated from each other, for example by moving the blow mold part 10 downwards together with the first neck part 104 and the second neck part 204, cf. Figure 12b.

[0122] The following describes, with reference to Figures 13 to 16, how the first neck part 104 is separated from the blow mold part 10, in particular from the first insert part 40 of the first blow mold part 10.

[0123] To simplify the disassembly of the first neck part 104 from the first insert part 40, it is preferred that the first neck part 104 has an engagement surface 182 for a tool, for example, for a first wrench. The first insert part 40 also has an engagement surface 184 for another tool, in particular for another wrench.

[0124] Figure 14 shows two wrenches 186 and 188, each engaged with the aforementioned engagement surfaces 182 and 184. The first wrench 186 is used to unscrew the first neck section 104 from the first insert 40. The second wrench 188 is used to secure the first insert 40. Torques applied to the first neck section 104 via the wrench 186 are transferred through the first insert 40 to the second wrench 188. This has the advantage that the disassembly forces generated when removing the first neck section 104 from the blow-molded part 10 are not transmitted into the plastic material of the blow-molded body 12. This enables a particularly simple and gentle separation of the first neck part 104 from the first insert part 40 and thus from the blow mold body 12 of the blow mold part 10 .

[0125] It is understood that after demolding a blow-molded part 10, which is still connected to at least one neck section 104, 204, the device 50 is already usable again for the production of another blow-molded part 10. For this purpose, an additional first neck section is provided, which is identical to the first neck section 104 in terms of its construction and function. Furthermore, an additional second neck section is provided, which is identical to the second neck section 204 in terms of its construction and function.

[0126] The additional neck sections are connected to the respective base sections 102, 202 of the respective mandrels 84, 86, so that another blow molded part 10 can be produced, according to the sequence shown in Figures 6a to 12b. In this way, idle times of the device 50 can be avoided. At the same time, a particularly gentle finishing process of the blow molded part 10 is possible, whereby this finishing process also includes the separation of at least one neck section 104, 204 from at least one insert section 40, 42. A further embodiment of a blow molded part 10 is described below with reference to Figures 17 and 18.

[0127] The blow-molded part 10 corresponds essentially in its structure and function to the blow-molded part 10 according to Figures 1 and 2. In contrast to the blow-molded part 10 according to Figures 1 and 2, the blow-molded part 10 according to Figures 17 and 18 does not have inserts 42, 44. Instead, cylindrical nozzles 43, 44 are provided in the respective neck sections 24, 26, each of which is integrally formed with the disc-shaped sections 36, 38. The cylindrical nozzles 43, 44 each have hollow cylindrical inner surface sections 45, 46.

[0128] The inner surface sections 45, 46 are molded by outer surfaces 176, 276 of the respective neck parts 104, 204, see Figures 19a and 20a. During the demolding of a preform 152 with blown air, the outer surfaces 176, 276 are positioned in the respective neck areas 162, 164 of the tool 74 and mold the inner surface sections 45, 46 of the blow mold part 10 there, see Figure 21b.

[0129] In the embodiments of the neck parts 104, 204 shown in Figures 19a to 20b, the outer surfaces 176, 276 are formed by respective impression cylinders 190, 290, which are held on a respective retaining body 192, 292 of the respective neck parts 104, 204, in particular screwed on.

[0130] Furthermore, regarding the construction and function of the blow molded body 10 according to Figures 17 and 18, reference is made to the preceding description of the blow molded body 10 according to Figures 1 and 2. With regard to the device 50 and the manufacture of the blow molded body 10 according to Figures 17 and 18, reference is also made to the preceding description, in particular to Figures 3a to 12b.

[0131] It is understood that an embodiment of a blow-molded body 10 not shown in the drawing has only a neck section 24 or 26 on which an insert 40 or 42 may or may not be arranged.

[0132] It is also possible that a blow molded part 10 has two

[0133] neck sections 24, 26, wherein one of the neck sections 24, 26 is provided with an insert 40 or 42 and wherein the other neck section 26, 24 has a cylindrical nozzle 43 or 44 with a hollow cylindrical inner surface section 45 or 46.

Claims

Patent claims 1. Device (50) for extrusion blow molding of a blow molded part (10) , comprising an extrusion die (82) for extruding a tubular preform (152) , comprising a multi-part tool (74) which has a cavity (154) for arranging the preform (152), wherein the cavity (154) opens at a first neck region (162) of the tool (74) , and comprising a first mandrel (84) for arranging on and / or in the first neck region (162) , characterized in that the first mandrel (84) is multi-part along a central first mandrel axis (100) and comprises a first base part (102) furthest from the cavity and a first neck part (104) closer to the cavity , wherein the first base part (102) and the first neck part (104) are detachably connected to each other via a first connecting device (106) .

2. Device (50) according to claim 1, characterized in that the first connecting device (106) comprises a coupling device, in particular a quick coupling device.

3. Device (50) according to one of the preceding claims, further comprising a first control device (98) for controlling the connection state of the first connection device (106), in particular for remote control of the connection state of the first connection device (106).

4. Device (50) according to one of the preceding claims, characterized in that the first neck part (104) has an outer surface (176) which is designed to form a mold of a first inner surface section (45) of the blow molded part (10).

5. Device (50) according to one of the preceding claims, characterized in that the first neck part (104) is detachably connectable or connected to a first insert part (40), wherein the first insert part (40) is designed to remain on and / or in the blow mold part (10).

6. Device (50) according to one of the preceding claims, further comprising an additional first neck part near the cavity, which can be detachably connected to the first base part (102) instead of the first neck part (104).

7. Device (50) according to one of the preceding claims, characterized in that the first mandrel (84) is arranged in the area of ​​a side of the tool (74) facing the extrusion nozzle (82), or that the first mandrel (84) is arranged in the area of ​​a side of the tool (74) facing away from the extrusion nozzle (82).

8. Device (50) according to one of the preceding claims, characterized in that the first mandrel (84) has a first blowing channel (144) for introducing blowing air into a cavity (150) enclosed by the preform (152).

9. Device (50) according to one of the preceding claims, characterized in that the cavity (154) opens at a second neck region (164) of the tool (74), and that the device (50) has a second mandrel (86) for arrangement on and / or in the second neck region (164) of the tool (74), wherein the second mandrel (86) is multi-part along a central second mandrel axis (200) and has a second base part (202) far from the cavity and a second neck part (204) close to the cavity, wherein the second base part (202) and the second neck part (204) are detachably connected to each other via a second connecting device (206).

10. Device (50) according to claim 9, characterized in that the second connecting device (206) comprises a coupling device, in particular a quick coupling device.

11. Device (50) according to claim 9 or 10, further comprising a second control device for controlling a connection state of the second connection device (206), in particular for remote control of the connection state of the second connection device (206), wherein - with at least an indirect reference to claim 3 - the second control device may be formed by the first control device (98).

12. Device (50) according to one of claims 9 to 11, characterized in that the second neck part (204) has an outer surface (276) which is designed for molding a second inner surface section (46) of the blow mold part (10).

13. Device (50) according to one of claims 9 to 12, characterized in that the second neck part (204) is detachably connectable or connected to a second insert part (42), wherein the second insert part (42) designed to remain on and / or in the blow molded part (10).

14. Device (50) according to one of claims 9 to 13, further comprising an additional second neck part near the cavity, which can be detachably connected to the second base part (202) instead of the second neck part (204).

15. Device (50) according to one of claims 9 to 14, characterized in that the first mandrel (84) and the second mandrel (86) are arranged on opposite sides of the tool (74).

16. Device (50) according to one of claims 9 to 15, characterized in that the second mandrel (86) has a second blowing channel (244) for introducing blowing air into a cavity (150) enclosed by the preform (152).

17. Method for producing a blow-molded part (10), in particular using a device (50) according to one of the preceding claims, comprising: a) providing a multi-part tool (74) having a cavity (154) for forming a blow-molded part (10), wherein the cavity (154) opens at a first neck region (162) of the tool (74), b) providing a multi-part first mandrel (84) extending along a central first mandrel axis (100), with a first base part (102) furthest from the cavity and with a first neck part (104) closer to the cavity, c) detachably connecting the first base part (102) and the first neck part (104), d) extruding a tubular preform (152), e) Arranging the preform (152) in the open tool (74), f) Arranging the first neck part (104) on and / or in the first neck region (162) of the tool (74), g) Closing the tool (74) so ​​that the preform (152) is arranged in the cavity (154) of the tool (74), h) Introducing compressed air into a cavity (150) enclosed by the preform (152) to deform the preform (152) and formed a first blow mold! 1s (10) , i) opening the tool (74) , j ) releasing the connection between the first base part 102 and the first neck part (104) , k) separating the first base part (102) from the first neck part (104) , leaving the first neck part (104) attached to the first blow mold part (10), optional 1) : cooling the first blow mold part (10) , m) separating the first neck part (104) from the first blow mold! 1 (10) .

18. The method of claim 17, further comprising - Molding of an inner surface section (45) of the first blow mold part (10) on an outer surface (176) of the first neck part (102) .

19. Method according to claim 17 or 18, further comprising - preferably according to b) or c): providing a first insert (40) and connecting the first insert (40) to the first neck part (104) , - Carrying out m) with the proviso that the first neck part (104) is separated from the first insert part (40) of the first blow mold part (10).

20. Method according to any one of claims 17 to 19, further comprising n) providing an additional first neck part close to the cavity, which can be detachably connected to the first base part (102) instead of the first neck part (104), o) detachably connecting the first base part (102) and the additional first neck part, - Performing steps d) to m) according to claim 18 to produce a second blow molded part (10) , wherein the additional first neck part takes the place of the first neck part (104).

21. Method according to claim 20, characterized in that the additional first neck part is connected to the first base part (102) at least during the cooling of the first blow mold part (10) and / or during the separation of the first neck part (104) from the first blow mold part (10) and / or during a post-processing of the first blow mold part (10).

22. A method according to any one of claims 17 to 21, wherein the cavity (154) of the multi-part tool (74) also opens onto a second neck region (164) of the tool (74), the method further comprising: b2) providing a multi-part second mandrel (86) extending along a central second mandrel axis (200), with a second base part (202) furthest from the cavity and with a second neck part (204) closer to the cavity, c2) releasably connecting the second base part (202) and the second neck part (204), f2) arranging the second neck part (204) on and / or in the second neck region (164) of the tool (74), j2) releasing the connection between the second base part (202) and the second neck part (204) , k2 ) Separating the second base part (202) from the second neck part (204) , wherein the second neck part (204) remains attached to the first blow mold part (10), m2) Separating the second neck part (204) from the first blow mold part (10) .

23. The method of claim 22, further comprising - Molding of an inner surface section (46) of the second blow mold part (10) on an outer surface (276) of the second neck part (204) .

24. Method according to claim 22 or 23, further comprising - preferably according to b2) or c2): providing a second insert (42) and connecting the second insert (42) to the second neck part (204) , - Execution of m2) with the proviso that the second neck part (204) is separated from the second insert part (42) of the first blow mold part (10).

25. Method according to any one of claims 22 to 24, further comprising n2) providing an additional second neck part close to the cavity, which can be detachably connected to the second base part (202) instead of the second neck part (204), o2) detachably connecting the second base part (202) and the additional second neck part, - Performing steps d) to m) according to claim 18 and steps d2) to m2) according to claim 22 to produce a second blow molded part (10) , wherein the additional second neck part takes the place of the second neck part (204).

26. Method according to claim 25, characterized in that the additional second neck part is connected to the second base part (202) at least during the cooling of the first blow mold part (10) and / or during the separation of the second neck part (204) from the first blow mold part (10) and / or during a post-processing of the first blow mold part (10).

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