Injection mold and method for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container
Patent Information
- Application Number
- CA3086112
- Authority / Receiving Office
- CA · CA
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2017-11-03
- Filing Date
- 2018-10-22
- Publication Date
- 2026-09-08
- Estimated Expiration
- 2038-10-22
Abstract
Description
Injection mold and method for producing a double walled drink- ing vessel, the double walled drinking vessel comprising an outer container and an inner container The present invention relates to an injection mold and a meth- od for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container. Double walled drinking vessels comprising an outer container and an inner container in many cases encase a hollow space be- tween them. The air captured in that hollow space has insulat- ing properties so that the adjustment time of the temperature of the liquid inside the inner container to the ambient tem- perature is significantly extended compared to single wall drinking vessels. In other words cold beverages will longer stay cold and hot beverages will longer stay hot. Due to the insulating properties the hand of the user holding the vessel is exposed to the temperature of the beverage only to a lim- ited extent. The danger that the hand gets burned or cold is reduced. Double walled drinking vessels are for example disclosed in WO 2015 / 091003 A1 and WO 2016 / 083226 A1. In the first case the outer container is connected to the inner container by a form closure whereas in the latter case the outer container is frictionally engaged to the inner container. Another double walled drinking vessel is distributed under the trademark "Pavina". In this double walled drinking vessel the outer and inner container are injection molded and welded together by ultrasonic welding. A certain disadvantage of this way to con- nect the outer and the inner container to each other is that the weld seam may not be absolutely tight so that despite a 2 proper mechanical connection air and water may ingress into the hollow space, in particular when the vessel is cleaned by means of a dishwasher. The water may condense inside the hollow space leading to a disadvantageous appearance. It is one task of one embodiment of the present invention to present an injection mold and a method for producing a double walled drinking vessel leading to an improved connection between the outer container and the inner container of a double walled drinking vessel. One embodiment of the invention is directed to an injection mold for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container, the injection mold comprising at least one first mold portion, at least one second mold portion facing the first mold portion, the first mold portion and the second mold portion being axially movable relative to each other, the first mold portion forming at least one first cavity corresponding to the out-er shape of the outer container and at least one second cavity corresponding to the outer shape of the inner container, the first cavity and the second cavity located concentrically with respect to a central axis of the first mold portion, an index plate rotatable around and axially movable along the central ax-is relative to the first mold portion, the index plate comprising at least a first core corresponding to the inner shape of the outer container and at least a second core corresponding to the inner shape of the inner container, the first cavity having a first cavity injec- tion gate for injecting a mold material into the first cavity for forming the outer container, the second cavity having a second cavity injection gate for injecting a mold material in- to the second cavity for forming the inner container, and the first cavity having a further injection gate for injecting a joint material for joining the outer container and the inner container. The injection mold comprises an index plate that comprises two different kind of cores, namely the first cores and the second cores. Moreover, the first injection mold portion comprises first cavities and second cavities. When the first cores are inserted into the first cavities, a mold material can be in- jected through the first cavity injection gate thereby forming the outer container. Correspondingly, the inner container is formed when the second core is inserted into the second cavity and a mold material is injected though the second cavity in- jection gate. The second cores are not only used to form the inner container but also to remove the inner container from the second cavity and to introduce the inner container into the first cavity comprising the outer container by axially and rotatably moving the index plate. The second cores have thus also a transport- ing function. When the inner container is introduced into the first cavity and thus into the outer container, the two con- tainers may be connected to each other by injecting a joint material into the first cavity. For this purpose the first cavity comprises a further injection gate for injecting the joint material. The mold material is a thermoplastic resin, e.g. Tritan. The joint material may be the same thermoplastic resin, however, the joint material may also be a different thermoplastic resin or at least having a different color to provide the double walled drinking vessel with an eye-catching appearance. Compared to the weld seam obtained by ultrasonic welding the injection of the joint material for joining the outer and the inner container to each other leads to a better bond so that the probability that water may ingress into the hollow space between the outer and the inner container is significantly re- duced. Moreover, the double walled drinking vessel is com- pletely finished when leaving the injection mold. Further pro- duction steps are not necessary which is in contrast to the connection of the outer and the inner container by ultrasonic welding. Thus the production process is accelerated and more efficient. According to another embodiment at least the second core com- prises holding means for holding the inner container on the second core and / or for releasing the inner container from the second core. As already described above the second core is used to remove the inner container out of the second cavity and to insert the inner container into the outer container and the first cavity. At the same time the outer container has to remain in the first cavity when the first core is extracted from the first cavity. To avoid that the inner container re- mains in the second cavity or detaches from the second core when being transferred the second core comprises the holding means. The holding means may comprise activatable suction means that produce a negative pressure between the second core and the inner container thereby attaching the inner container to the second core. The suction means may be deactivated when the inner container is introduced into the outer container. The holding means increase the process reliability. In a further embodiment at least the first core is axially mounted to the index plate. As already mentioned above the second core is removed from the second cavity together with the inner container and introduced into the first cavity and the outer container. The outer container and thus the first cavity is bigger in size compared to the inner container and the second cavity. Therefore, the first core cannot or only partially be inserted into the second cavity so that the in- jection mold cannot be completely closed. When the second core is introduced into the second cavity the index plate is axial- ly moved. As the first core and the second core are mounted to the same index plate, also the first core is axially moved. The axial movability avoids a damaging impact of the first core on the first mold portion. According to a further developed embodiment the index plate comprises a preload element forcing the first core into a po- sition in which the first core maximally protrudes from the index plate. The position in which the first core maximally protrudes from the index plate is the position which is needed to produce the outer container with the requested dimensions. The preload element ensures the first core is automatically placed back into this positon after having been displaced by the first mold portion upon closing the injection mold. In another embodiment the first mold portion comprises a num- ber of additional cavities that is equal to or exceeds the number of the first cavities, wherein a first core can be ful- ly inserted into the additional cavity, the index plate com- prises a number of first cores that is equal to the number of the first cavities, and the angle between a first cavity and a neighboring additional cavity is the same as between a first cavity and a neighboring second cavity. As already mentioned before the first core is axially moved in the same way as the second core as the first and the second core are both mounted to the same index plate. While the second core can be inserted into the first cavity and the second cavity the first core can due to its size not be fully inserted to the second cavity. In this embodiment the first mold portion comprises an additional cavity into which the first core can be inserted when the sec- ond core is inserted into the first cavity together with the inner container. A damaging impact of the first core on the first mold portion is thus avoided. It is not necessary to mount the first core to the index plate in an axially movable way. Further, the additional cavities have the same structure as the first cavities. In particular the additional cavities can be identical to the first cavities so that they cannot be dis- tinguished anymore. Thus the manufacturing process of the first mold portion is facilitated as no distinction between the first and the additional cavities has to be made. Moreo- ver, as in this case the first cavity can be used to produce a further outer container, the productivity of the production process may be increased. In a further embodiment the first mold portion comprises four first cavities and four second cavities equally arranged around the central axis of the first mold portion, the first cavities subdivided into two first cavity pairs and the second cavities subdivided into two second cavity pairs, the first and second cavity pairs are arranged alternately to each oth- er, and the index plate comprises two first cores and four second cores, the two first cores being arranged opposite to each other with reference to the central axis, respectively two of the second cores being adjacently arranged to each of the first cores, the second cores enclosing an angle of 45° with the adjacent first core with reference to the central ax- is. As will be later explained in detail, in this embodiment two finished double walled drinking vessels can be withdrawn each time the injection mold is opened. Moreover, the index plate only needs to be rotated by 45° which contributes to a fast and efficient production process. A further realization of the present invention is directed to an injection mold machine comprising an injection mold accord- ing to one of the embodiments presented above. An implementation of the invention is directed to a method for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container using an injection mold machine according to the re- alization mentioned before, comprising following steps: - rotating the index plate into a position in which the first core is axially aligned with a first cavity and the second core is axially aligned with a second cavity, - closing the injection mold by axially moving the first mold portion relative to the second mold portion, thereby inserting the first core into the first cavity and the second core into a second cavity, - injecting a mold material into the first cavity through the first cavity injection gate, thereby forming an outer container, - injecting a mold material into the second cavity through the second cavity injection gate, thereby forming an in- ner container, - opening the injection mold by axially moving the first mold portion relative to the second mold portion, such that the outer container remains in the first cavity and the inner container is removed from the second cavity by the second core, - rotating the index plate into a position in which the sec- ond core holding an inner container is axially aligned with a first cavity comprising an outer container, - closing the injection mold, thereby inserting the inner container into the outer container, - joining the outer container and the inner container by in- jecting a joint material through the further injection gate of the first cavity, and - opening the injection mold and ejecting the double walled drinking vessel. The technical effects and advantages as discussed with regard to the injection mold equally apply to the injection molding machine and the method for producing a double walled drinking vessel. Briefly, the injection mold machine enables the pro- duction of a double walled drinking vessel having a water tight bond between the outer container and the inner container so that the ingress of water into the hollow space is avoided. Moreover, the double walled drinking vessel is completely fin- ished after being withdrawn from the injection mold machine so that no further manufacturing process in particular for join- ing the outer container and the inner container is needed as is the case when the outer container and the inner container are welded together. The production process is thus faster and more efficient. Another implementation of the method comprises the following steps: - rotating the index plate into a position in which the two first cores are axially aligned with two first cavi- ties, the two second cores are axially aligned with two second cavities and the two remaining second cores are axially aligned with two first cavities, _ closing the injection mold by axially moving the first mold portion relative to the second mold portion, there- by inserting the first cores into the first cavities, two of the second cores into the second cavities and the two remaining second cores into the two first cavities, - injecting a mold material into the first cavities into which the two first cores are inserted through the first cavity injection gate, thereby forming two outer con- tainers, - injecting a mold material into the second cavities into which the second cores are inserted through the second cavity injection gate, thereby forming two inner con- tainers, - opening the injection mold by axially moving the first mold portion relative to the second mold portion, such that the two outer containers remain in the respective first cavities and the two inner containers are removed from the respective second cavities by the second cores, - rotating the index plate forward by 45° into a position in which the second cores holding the two inner contain- ers are axially aligned with the two first cavities com- prising the two outer containers, the two first cores are axially aligned with two first cavities and the two remaining second cores are axially aligned with two sec- ond cavities, - closing the injection mold, thereby inserting the two inner containers into the two outer containers, insert- ing the first cores into the first cavities and insert- ing the two remaining second cores into the second cavi- ties, - joining the outer container and the inner container by injecting a joint material through the further injection gate of the first cavity, - injecting a mold material into the first cavities into which the two first cores are inserted through the first cavity injection gate, thereby forming two outer con- tainers, - injecting a mold material into the second cavities into which the second cores are inserted through the second cavity injection gate, thereby forming two inner con- tainers, - opening the injection mold such that the two outer con- tainers remain in the respective first cavities and the two inner containers are removed from the respective second cavities by the second cores, - ejecting the two double walled drinking vessels, _ rotating the index plate backward by 45° into a position in which the second cores holding the two inner contain- ers are axially aligned with the two first cavities com- prising the two outer containers, the two first cores are axially aligned with two first cavities and the two remaining second cores are axially aligned with two sec- ond cavities, and - closing the injection mold and starting again from the beginning. In this implementation of the method each time the injection mold is opened two finished double walled drinking vessels can be withdrawn from the injection mold. This method requires that the first mold portion comprises in total eight cavities, namely four first cavities and four second cavities. Although the first mold portion may be provided with a higher number of cavities the increase in complexity of the first mold portion would not justify the result, in this case a higher through- put. It has been found that the use of in total eight cavities provides a high throughput at a manageable complexity. Another implementation of the invention relates to a double walled drinking vessel, the double walled drinking vessel com- prising an outer container and an inner container, the double walled drinking vessel obtained by a method according to one of the methods previously described and / or by using an injec- tion molding machine as described before, wherein the outer container and the inner container are joined together by an injected thermoplastic resin. In known double walled drinking vessels the outer container and the inner container are joined by ultrasonic welding. However, the weld seam so obtained may not be water tight so that water may ingress into the hollow space between the outer container and the inner container and condense in the hollow space leading to a disadvantageous ap- pearance. In the double walled drinking vessel obtained by the proposed method the outer container and the inner container are joined inside the injection molding machine by injecting a thermoplastic resin. The bond so obtained is much better so that the probability that water may ingress into the hollow space between the outer and the inner container is signifi- cantly reduced. Another aspect of the present invention is directed to a com- puter program for conducting the method as previously de- scribed, wherein the computer program comprises a program code for causing the control unit to perform the steps of the meth- od previously described, when the computer program is executed on the control unit. The present invention is described in detail with reference to the drawings attached wherein Figures 1a, 1b, 1c, 1d, 2a, 2b, 3a, 3b, 4a, 4b, 5a, and 5b show a first embodiment of an injec- tion molding machine according to the in- vention and different steps of a method by which the molding machine according to the first embodiment may be operated, by means of principle sketches, Figure 6 a perspective view on an index plate of a second embodiment of the molding machine according to the invention, Figure 7 a perspective view on a first mold portion index plate of a second embodiment of the molding ma- chine according to the invention, Figures 8, 9, 10, and 11 different steps of a method by which the molding machine according to the second embodiment may be operated, Figure 12 a third embodiment of an injection molding ma- chine, and Figure 13 a fourth embodiment of the injection molding ma- chine, by means of principle sketches. Figure 1a shows a principle view on an injection molding ma- chine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> according to a first embodiment and Figure 1b a sec- tion along the section plane Z-Z as defined in Figure 1a. For the sake of comprehensibility only the relevant parts of the injection molding machine are shown, particularly in Figure 1a. The injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is configured to produce a double walled drinking vessel 12 having an outer container 14 and an inner container 16 (see Figures 4b and 5b). The injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> comprises an injection mold 18 having a first mold portion 20 and a second mold portion 22. The first mold portion 20 and the second mold portion 22 are facing each other and are axially movable along a central axis A of the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics>. To this end the first mold portion 20 and the second mold portion 22 are con- nected to a number of guide rods 24. Moreover the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is equipped with driving means 26 for axi- ally moving the first mold portion 20 and the second mold por- tion 22 along the guide rods 24. The first mold portion 20 comprises one first cavity 28 and one second cavity 30 that are separately shown in Figures 1c and 1d, respectively. The first cavity 28 and the second cavi- ty 30 are located opposite of the central axis A and thus en- close an angle of 180°. The first cavity 28 is equipped with a first cavity injection gate 32 for injecting a mold material into the first cavity 28, thereby forming the outer container 14. The second cavity 30 is accordingly equipped with a second cavity injection gate 34 for injecting a mold material into the second cavity 30, thereby forming the inner container 16. The first cavity 28 comprises a further injection gate 36 for injecting a joint material into the first cavity 28. The in- jection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> comprises a manifold 38 for guiding the mold material to the first and second cavity injection gate 32, 34 and the joint material to the further injection gate 36. Moreover, the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> comprises an index plate 40 which is mounted to the second mold portion 22 and thus movable along the central axis A together with the second mold portion 22. The index plate 40 is rotatable around the central axis A by means of a rotary drive means 44. The index plate 40 further comprises a first core 46 and a second core 48. The first core 46 has a shape defining the inner shape of the outer container 14 (see Figures 2b and 3b) whereas the second core 48 has a shape defining the inner shape of the in- ner container 16 (see Figures 4b and 5b). As demonstrated in Figure 1b the first core 46 is mounted on the index plate 40 axially movable along the central axis A. The index plate 40 comprises a preload element 50 forcing the first core 46 into a position in which the first core 46 maxi- mally protrudes from the index plate 40. The injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> further comprises a control unit 42 to coordinate the movements of the first mold portion 20, the second mold portion 22 and the index plate 40 and to control the injection of the mold material and the joint mate- rial into the respective cavities. In the following the different steps of a method will be ex- plained by which the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> may be oper- ated. In Figure 1a and 1b the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is opened and the index plate 40 is in a position in which neither the first core 46 nor the second core 48 are axially aligned with the first cavity 28 or the second cavity 30. As indicated by the arrow P the index plate 40 then turned counterclockwise, in this case by 90°, so that the first core 46 is axially aligned with the first cavity 28 and the second core 48 is ax- ially aligned with the second cavity 30. This position is shown in Figure 2a. Now the molding machine is closed thereby inserting the first core 46 into the first cavity 28, as shown in Figure 2b, and the second core 48 into the second cavity 30 (not shown). In remaining in this position the mold material is injected into the first cavity 28 through the first cavity injection gate 32, thereby forming an outer container 14 (Figure 3b), and into the second cavity 30 through the second cavity injec- tion gate 34, thereby forming an inner container 16 (not shown). The mold material may be a thermoplastic resin such as Tritan. After the thermoplastic resin has cured the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is opened by moving the first mold portion 20 and the second mold portion 22 axially away from each other along the central axis A. The second core 48 comprises holding means 52, in this case activatable suction means 54 that produce a negative pressure acting between the inner container 16 and the second core 48 (see Figures 4b and 5b). As a result the inner container 16 is removed from the second cavity 30 when the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is opened. In contrast to that the outer container 14 remains in the first cavity 28. After that the index plate 40 is rotated by 180° and the in- jection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is closed again. When comparing the first cavity 28, e.g. shown in Figure 1c, and the second cavity <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>, e.g. shown in Figure 1d and / or when comparing the first core 46 and the second core 48, e.g. in Figure 1b, it becomes clear that they are different in size. In consequence of that the second core 48 can completely be inserted into the first cavity 28 and the second cavity 30, whereas the first core 46 can only completely be inserted into the first cavity 28. Depending on the design of the double walled drinking vessel 12 the first core 46 may not at all or only partially be inserted into the second cavity 30. Without any countermeasures the first core 46 would impact on the first mold portion 20 and cause severe damages in the injec- tion mold 18 when closing the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics>. For preventing such damages the first core 46 is mounted on the index plate 40 axially movable along the central axis A. The preload element 50 is forcing the first core 46 into a po- sition in which the first core 46 maximally protrudes from the index plate 40. This position is shown in Figures 1b, 2b and 3b. When the injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is closed the first core 46 is axially moved against the force exerted by the preload element 50. Concomitantly the second core 48 together with the inner container 16 is inserted into the first cavity 28 and into the outer container 14 as shown in Figure 4b. As evident from Figure 4b the outer container 14 and the inner container 16 are configured such that an annular space 56 near the open- ing of the outer container 14 and the inner container 16 is created. Moreover the outer container 14 and the inner con- tainer 16 encase a hollow space 58 between them. Now a joint material is injected into the first cavity 28 through the further injection gate 36 (Figure 5b). The further injection gate 36 is positioned such that the joint material is injected into the annular space 56. The joint material may be a thermoplastic resin and may be identical to the thermo- plastic resin used as the mold material for producing the out- er container 14 and the inner container 16. After the joint material is injected into the annular space 56 and has cured the double walled drinking vessel 12 is completed as shown in Figure 5b. The injection molding machine <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> is now opened and the double walled drinking vessel 12 is ejected. In Figure 6 the index plate 40 and in Figure 7 the first mold portion 20 of a second embodiment of the injection molding ma- chine <semantics>102<annotation encoding="application / x-tex">10_2< / annotation>< / semantics> are shown each by means of a perspective view. In Figures 8 to 11 the method by which the injection mold 18 may be operated is shown comprising the index plate 40 and the first mold portion 20 illustrated in Figures 6 and 7. Referring to Figure 7 the first mold portion 20 comprises in total eight cavities, namely four first cavities 281 to 284 and four second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics> to <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics>. The cavities <semantics>287<annotation encoding="application / x-tex">28_7< / annotation>< / semantics> 30 are equal- ly arranged around the central axis A so that they form an an- gle <semantics>α<annotation encoding="application / x-tex">\alpha< / annotation>< / semantics> of 45° as shown in Figure 8. The first cavities 281 to 284 are grouped pairwise around the central axis A so that they form two first cavity pairs 28P1 and 28P2. The second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics> to <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics> are grouped pairwise around the central axis A so that they form two second cavity pairs 30P1 and 30P2. The first cavity pairs 28P1 and 28P2 are each arranged adjacent to the second cavity pairs 30P1 and 30P2. In Figure 7 the further injection gates 36 of the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics> to <semantics>284<annotation encoding="application / x-tex">28_4< / annotation>< / semantics> are clearly visible. As shown in Figure 6 the index plate 40 comprises two first cores <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> and four second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics> to <semantics>484<annotation encoding="application / x-tex">48_4< / annotation>< / semantics>. The two first cores 461, 462 are arranged opposite to each other with refer- ence to the central axis A. The two second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics> are arranged adjacent to the first cores 46 and the two second cores <semantics>483<annotation encoding="application / x-tex">48_3< / annotation>< / semantics>, <semantics>484<annotation encoding="application / x-tex">48_4< / annotation>< / semantics> are arranged adjacent to the first core <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics>, the second cores 481 to 484 enclosing an angle of 45° with the ad- jacent first core <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> with reference to the central axis Α. The second embodiment of the injection molding machine 102 may be operated as follows. In Figure 8 the index plate 40 is placed in a position in which the first cores <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> are in- serted into the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>283<annotation encoding="application / x-tex">28_3< / annotation>< / semantics> and two of the second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>483<annotation encoding="application / x-tex">48_3< / annotation>< / semantics> are inserted into the second cavities <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics> and <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics> whereas the remaining two second cores 482, 484 are inserted into the remaining first cavities 282, 284. The mold material is injected into the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>283<annotation encoding="application / x-tex">28_3< / annotation>< / semantics> into which the first cores <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> are inserted and into the second cavities <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>, <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics> into which the second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>483<annotation encoding="application / x-tex">48_3< / annotation>< / semantics> are inserted. It is noted that no mold material is injected into the remaining first cavities 282, 284 into which the remaining two second cores 482, 484 are inserted. Consequently two outer containers 14 are produced in the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>283<annotation encoding="application / x-tex">28_3< / annotation>< / semantics> and two inner containers 16 are produced in the second cavities <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>, <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics>. Now the injection mold 18 is opened and the first cores <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> and the second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics> to <semantics>484<annotation encoding="application / x-tex">48_4< / annotation>< / semantics> are removed from the re- spective first and second cavities 28, 30. As already men- tioned with reference to the first embodiment of the injection mold <semantics>101<annotation encoding="application / x-tex">10_1< / annotation>< / semantics> the second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>483<annotation encoding="application / x-tex">48_3< / annotation>< / semantics> also withdraw the inner con- tainers 16 from the respective second cavities 302, 304 whereas the outer containers 14 remain inside the first cavities <semantics>281<annotation encoding="application / x-tex">28_{1}< / annotation>< / semantics>, <semantics>283<annotation encoding="application / x-tex">28_3< / annotation>< / semantics>. The index plate 40 is now rotated by <semantics>45∘<annotation encoding="application / x-tex">45^{\circ}< / annotation>< / semantics> into a first ro- tary direction indicated by the arrow P (Figure 9). The injec- tion mold 18 is closed again so that by means of the two sec- ond cores 481, 483 the two inner containers 16 are introduced into the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>283<annotation encoding="application / x-tex">28_3< / annotation>< / semantics> comprising the outer contain- ers 14. The first cores <semantics>461<annotation encoding="application / x-tex">46_1< / annotation>< / semantics>, <semantics>462<annotation encoding="application / x-tex">46_2< / annotation>< / semantics> are now introduced into the first cavities <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics>, <semantics>284<annotation encoding="application / x-tex">28_4< / annotation>< / semantics> and the two remaining second cores <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics>, <semantics>484<annotation encoding="application / x-tex">48_4< / annotation>< / semantics> are now introduced into the two second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>, <semantics>303<annotation encoding="application / x-tex">30_3< / annotation>< / semantics>. The joint material is now injected into the first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, 283 through the further injection gates 36, thereby completing two double walled drinking vessels 12 (see Figure 10). At the same time the mold material is introduced into the two first cavities <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics>, <semantics>284<annotation encoding="application / x-tex">28_4< / annotation>< / semantics> and the two second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>, <semantics>303<annotation encoding="application / x-tex">30_3< / annotation>< / semantics> so that two outer containers 14 and two inner containers 16 are formed. After curing the injection mold 18 is opened and the two completed double walled drinking vessels 12 are ejected. After that the index plate 40 is rotated 45° into a second ro- tary direction opposite of the first rotary direction as indi- cated by the arrow P in Figure 10 into a position shown in Figure 11. The injection molding machine <semantics>102<annotation encoding="application / x-tex">10_2< / annotation>< / semantics> is closed and by means of the second cores <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics>, <semantics>484<annotation encoding="application / x-tex">48_4< / annotation>< / semantics> the two inner containers 16 are introduced into the first cavities 282, 284 comprising the outer containers 14. The joint material is injected into the first cavities <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics>, <semantics>284<annotation encoding="application / x-tex">28_4< / annotation>< / semantics> through the further injection gates <semantics>36<annotation encoding="application / x-tex">36< / annotation>< / semantics>, thereby competing two double walled drinking vessels 12. At the same time mold material is injected into the first cavi- ties <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics> and the second cavities <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>, <semantics>304<annotation encoding="application / x-tex">30_4< / annotation>< / semantics> thereby forming two outer containers 14 and two inner containers 16 as shown in Figure 8. The described steps are now repeated. By means of the method the injection molding machine <semantics>102<annotation encoding="application / x-tex">10_2< / annotation>< / semantics> ac- cording to the second embodiment is operated two double walled drinking vessels 12 are completed and ejected each time the injection molding machine <semantics>102<annotation encoding="application / x-tex">10_2< / annotation>< / semantics> is opened. In Figure 12 a third embodiment of an injection molding ma- chine <semantics>103<annotation encoding="application / x-tex">10_3< / annotation>< / semantics> is shown by means of a principle sketch. The first mold portion 20 comprises in total three cavities, namely one first cavity 28, one second cavity 30 and one additional cavi- ty 60. The cavities 28, 30, 60 are equally arranged around the central axis A. The index plate 40 comprises one first core 46 and one second core 48 enclosing an angle <semantics>α<annotation encoding="application / x-tex">\alpha< / annotation>< / semantics> of 120° with ref- erence to the central axis A. The additional cavity 60 is con- figured such that the first core 46 may be completely inserted into the additional cavity 60. The injection molding machine <semantics>103<annotation encoding="application / x-tex">10_3< / annotation>< / semantics> is operated as follows. The index plate 40 is rotated into a position in which the first core 46 is aligned with the first cavity 28 and the second core 48 is aligned with the second cavity 30. The injection molding machine 103 is closed, thereby inserting the first core 46 into the first cavity 28 and the second core 48 into the second cavity 30. The mold material is now injected into the first cavity 28 and the second cavity 30, thereby producing one outer container 14 and one inner container 16. The injec- tion molding machine 103 is now opened and the inner container 16 is withdrawn from the second cavity 30 by the second core 48. The index plate 40 is now rotated counterclockwise into a first rotational direction by 120° so that the second core 48 is axially aligned with the first cavity 28 and the first core 46 is axially aligned with the additional cavity 60. The in- jection molding machine <semantics>103<annotation encoding="application / x-tex">10_3< / annotation>< / semantics> is now closed and the joint materi- al is injected into the first cavity 28 through the further injection gate 36, thereby completing one first double walled drinking vessel 12. After curing the injection molding machine 103 is opened and the completed double walled drinking vessel 12 is ejected. The index plate 40 is rotated by 120° into a second rotational direction opposite the first rotational di- rection and the described steps are conducted again. In this embodiment one completed double walled drinking vessel 12 is ejected every second time the injection molding machine 103 is opened. In Figure 13 a fourth embodiment of an injection molding ma- chine <semantics>104<annotation encoding="application / x-tex">10_4< / annotation>< / semantics> is shown by means of a principle sketch. The first mold portion 20 comprises in total four cavities, namely two first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics> and two second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>, <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>. The cavities 28, 30 are equally arranged around the central axis A. The first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics> form a first cavity pair <semantics>28P<annotation encoding="application / x-tex">28P< / annotation>< / semantics> and the second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>, <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics> form a second cavity pair <semantics>30P<annotation encoding="application / x-tex">30P< / annotation>< / semantics>. The two first cavities <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>, <semantics>282<annotation encoding="application / x-tex">28_2< / annotation>< / semantics> enclose an angle <semantics>α<annotation encoding="application / x-tex">\alpha< / annotation>< / semantics> of <semantics>90∘<annotation encoding="application / x-tex">90^{\circ}< / annotation>< / semantics> with each other with reference to the central axis A. The same is true for the second cavities <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>, <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>. The index plate 40 comprises one first core 46 and two second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics>, the two second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics> arranged opposite the central axis A and thus enclosing an angle of 180° with reference to the central axis A. The first core 46 is arranged in an angle of 90° with regard to the second cores <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics>, <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics> and with reference to the central axis A. The index plate 40 is rotated into a position in which the first core 46 is axially aligned with one of the first cavi- ties 28, in this case with the first cavity 282 and the second core <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics> is axially aligned with one of the second cavities 30, in this case with the second cavity <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics>. The other second core <semantics>482<annotation encoding="application / x-tex">48_2< / annotation>< / semantics> is axially aligned with the other first cavity <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>. The in- jection molding machine 104 is now closed and the mold material is injected into the first cavity 282 into which the first core 46 is introduced and into the second cavity <semantics>301<annotation encoding="application / x-tex">30_1< / annotation>< / semantics> into which the second core 481 is introduced, thereby producing an outer con- tainer 14 and one inner container 16. After that the injection molding machine 104 is opened and the index plate 40 rotated by 90° counterclockwise into a first rotational direction so that the second core 481 carrying the inner container 16 is axially aligned with the first cavity 282 and the first core 46 is axi- ally aligned with the other first cavity <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics>. The other second core 482 is now axially aligned with the other second cavity <semantics>302<annotation encoding="application / x-tex">30_2< / annotation>< / semantics>. The injection molding machine <semantics>104<annotation encoding="application / x-tex">10_4< / annotation>< / semantics> is now closed and the joint material is injected into the first cavity 282 through the further injection gate 36, thereby completing one double walled drinking vessel 12. At the same time the mold material is injected into the other first cavity <semantics>281<annotation encoding="application / x-tex">28_1< / annotation>< / semantics> and the second cav- ity 302, thereby producing an outer container 14 and an inner container 16. The injection molding machine 104 is opened and the completed double walled drinking vessel 12 is ejected. The index plate 40 is rotated by 90° in a second rotational direc- tion opposite to the first rotational direction. The inner container 16 is introduced into the outer container 14 and the joint material is injected into the other first cavity 281 through the further injection gate 36, thereby completing a double walled drinking vessel 12. Concomitantly molding mate- rial is injected into the first cavity 282 into which the first core 46 is introduced and into the second cavity 301 into which the second core <semantics>481<annotation encoding="application / x-tex">48_1< / annotation>< / semantics> is introduced, thereby producing an outer container 14 and an inner container 16. Now the described steps are repeated. In this embodiment one completed double walled drinking vessel 12 is ejected each time the injection molding machine <semantics>104<annotation encoding="application / x-tex">10_4< / annotation>< / semantics> is opened. Reference list [Image disponible dans le document PDF, Image available in the PDF document]
Claims
1. An injection mold for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container, the injection mold comprising - a first mold portion, - a second mold portion facing the first mold portion, - the first mold portion and the second mold portion being axially movable relative to each other, - the first mold portion forming a first cavity corre- sponding to an outer shape of the outer container and a second cavity corresponding to an outer shape of the in- ner container, the first cavity and the second cavity located concentrically with respect to a central axis of the first mold portion, - an index plate rotatable around and axially movable along the central axis relative to the first mold por- tion, the index plate comprising a first core corre- sponding to an inner shape of the outer container and a second core corresponding to an inner shape of the inner container, the first core being axially movably mounted to the index plate via a preload element, the preload element forcing the first core into a position in which the first core maximally protrudes from the index plate, - the first cavity having a first cavity injection gate for injecting a first mold material into the first cavi- ty for forming the outer container, - the second cavity having a second cavity injection gate for injecting a second mold material into the second cavity for forming the inner container, and the first cavity having a further injection gate for in- jecting a joint material for joining the outer container and the inner container.
2. The injection mold according to claim 1, wherein the second core comprises holding means for holding the inner container on the second core and for releasing the inner container from the second core.
3. Injection mold according to claim 1 or 2, wherein - the first cavity comprises a plurality of first cavi- ties, wherein the first core can be fully inserted into the plurality of first cavities, - the first core comprised of a plurality of first cores, a number of the plurality of first cores being equal to a number of the plurality of first cavities, and - an angle defined between one of the plurality of first cavities and a neighboring one of the plurality of first cavities is the same as another angle defined between the one of the plurality of first cavities and another neighboring one of the plurality of first cavities.
4. Injection mold according to claim 3, wherein the plurality of first cavities each have the same structure.
5. Injection mold according to claim 1, wherein the first cavity comprises four first cavities and the second cavity comprises four second cavities, the four first and second cavities equally arranged around the central axis of the first mold portion, the four first cavities subdivided into two first cavity pairs and the four second cavities subdivided into two second cavity pairs, the first and second cavity pairs are arranged alternately to each other, and the first core comprises two first cores and second core comprises four second cores, the two first cores being arranged opposite to each other with reference to the central axis, respectively two of the second cores being adjacently arranged to each of the first cores, the second cores enclosing an angle of 45° with an adjacent one of the two first cores with reference to the central axis.
6. An injection molding machine comprising the injection mold as defined in any one of claims 1 to 5.
7. The injecton mold of any one of claims 1 to 5, wherein the joint material is comprised of an injected thermoplastic resin.
8. Method for producing a double walled drinking vessel, the double walled drinking vessel comprising an outer container and an inner container using an injection mold machine ac- cording to claim 6, comprising following steps: - rotating the index plate into a position in which a first core is axially aligned with the first cavity and the second core is axially aligned with a second cavity, - closing the injection mold by axially moving the first mold portion relative to the second mold portion, there- by inserting the first core into the first cavity and the second core into a second cavity, - injecting a mold material into the first cavity through the first cavity injection gate, thereby forming an out- er container, - injecting a mold material into the second cavity through the second cavity injection gate, thereby forming an in- ner container, - opening the injection mold by axially moving the first mold portion relative to the second mold portion, such that the outer container remains in the first cavity and the inner container is removed from the second cavity by the second core, - rotating the index plate into a position in which the second core holding an inner container is axially aligned with a first cavity comprising an outer contain- er, - closing the injection mold, thereby inserting the inner container into the outer container, - joining the outer container and the inner container by injecting a joint material through the further injection gate of the first cavity, and - opening the injection mold and ejecting the double walled drinking vessel.
9. Method according to claim 8, wherein the injection molding machine comprises an injection mold according to any one of claims 1 to 5 and 7, comprising the following steps: - rotating the index plate into a position in which the two first cores are axially aligned with two first cavi- ties, two of the second cores are axially aligned with two second cavities and the two remaining second cores are axially aligned with two first cavities, - closing the injection mold by axially moving the first mold portion relative to the second mold portion, there- by inserting the first cores into the first cavities, two of the second cores into the second cavities and the two remaining second cores into the two first cavities, - injecting a mold material into the first cavities into which the two first cores are inserted through the first cavity injection gate, thereby forming two outer con- tainers, - injecting a mold material into the second cavities into which the second cores are inserted through the second cavity injection gate, thereby forming two inner con- tainers, - opening the injection mold by axially moving the first mold portion relative to the second mold portion, such that the two outer containers remain in the respective first cavities and the two inner containers are removed from the respective second cavities by the second cores, - rotating the index plate forward by 45° into a position in which the second cores holding the two inner contain- ers are axially aligned with the two first cavities com- prising the two outer containers, the two first cores are axially aligned with two first cavities and the two remaining second cores are axially aligned with two sec- ond cavities, _ closing the injection mold, thereby inserting the two inner containers into the two outer containers, insert- ing the first cores into the first cavities and insert- ing the two remaining second cores into the second cavi- ties, - joining the outer container and the inner container by injecting a joint material through the further injection gate of the first cavity, - injecting a mold material into the first cavities into which the two first cores are inserted through the first cavity injection gate, thereby forming two outer con- tainers, - injecting a mold material into the second cavities into which the second cores are inserted through the second cavity injection gate, thereby forming two inner con- tainers, - opening the injection mold such that the two outer con- tainers remain in the respective first cavities and the two inner containers are removed from the respective second cavities by the second cores, - ejecting the two double walled drinking vessels, - rotating the index plate backward by 45° into a position in which the second cores holding the two inner contain- ers are axially aligned with the two first cavities com- prising the two outer containers, the two first cores are axially aligned with two first cavities and the two remaining second cores are axially aligned with two sec- ond cavities, and - closing the injection mold and starting from the begin- ning again.