Double walled drinking vessel s are for example disclosed in WO 2015/091003 Al and WO 2016/083226 Al . 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 we1 d seam may not be absolutely tight so that despite a 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 hol ^¬ low 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 .

The task is solved by an injection mold according to claim 1, an injection molding machine according to claim 8, a method according to claim 9 and a double walled drinking vessel ac- cording to claim 11. Advantageous embodiments are subject of the sub-claims .

One embodiment of the invention is directed to an in jection mold for producing a double walled drinking vessel, the double walled drinking vessel compri sing an outer container and an inner container, the injection mo1d 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 port ion being axia lly movable relat ive to each other, the first mold portion forming at least one first cavity corre ^¬ sponding to the outer 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 axi s of the first mold portion, an index plate rotatabie around and axial ^¬ ly movable along the central axis relative to the first mold portion, the index plate compri sing at least a first core cor ^¬ responding 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 in jec- t ion 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 port ion 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 in jected 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 compri sing the outer container by axially and rotatably moving the index plate . The second cores have thus also a t ransport- 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 thermoplast ic resin, however, the joint material may also be a di fferent thermoplastic resin or at least having a different color to provide the double walled drinking vesse1 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 s igni fi cant ly reduced . Moreover, the double walled drinking vessel is com ^¬ pletely finished when leaving the injection mo1d . 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 proces s 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 compri se 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 axial ly 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 compri ses a preload element forcing the first core into a po ^¬ sition in which the first core maximally protrudes from the index plate . The posit ion 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 in ject ion mo1 d .

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 axial ly 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 port ion 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 axial ly movable way .

Further, the addit ional cavit ies have the same structure as the first cavities . In particular the additional cavities can be ident ical 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 addit ional 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 port ion comprises four first cavities and four second cavities equally arranged around the central axis of the first mold, the first cavit ies 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 other, 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 axis . As will be lat ^¬ er explained in detail, in this embodiment two finished double walled, drinking vessels can be withdrawn each time the injec ^¬ tion 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 di rected to an injection mold machine comprising an injection mold according to one of the embodiments presented above .

An implementation of the invent ion is di rected to a method for producing a double walled drinking vessel , the double walled drinking vessel comprising an outer container and an inner container us ing an injection mold machine according to the realization mentioned before, comprising following steps :

- rotating the index plate into a posit ion in which the first core is axial ly al igned 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 relat ive 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 relat ive 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,

- rotat ing the index plate into a posit ion 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 an 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 mo1d machine enables the pro ^¬ duction of a double wal led drinking vesse1 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 ves se1 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 :

- rotat ing 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 al igned with two first cavities,

- closing the injection mold by axially moving the first mold portion relative to the second mo1d port ion, there ^¬ by inserting the first cores into the first cavities, two of the second cores into the second cavit ies 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 containers,

- 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 containers,

- opening the injection mo1 d by axially moving the first mold portion relative to the second mold port ion, such that the two outer containers remain in the respective first cavities and the two inner containers are removed from the respect ive second cavities by the second cores,

- rotat ing the index plate forward by 45° into a position in which the second cores holding the two inner containers 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 cavit ies into which the two first cores are inserted, through the first cavity injection gate, thereby forming two outer containers,

- 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 containers,

- opening the injection mo1d such that the two outer containers remain in the respective first cavities and the two inner containers are removed from the respective second cavit ies by the second cores,

- ejecting the two double wal led. drinking vessels,

- rotat ing the index plate backward by 45 ° into a position in which the second cores holding the two inner containers are axially aligned with the two fi. rst 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 mo1d 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 requi res that the first mold portion comprises in total eight cavities, namely four first cavit ies 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 port ion 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 joint together by an injected thermoplast ic resin . In known double walled drinking vessel s the outer container and the inner container are joint 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 joint 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 hoi low space between the outer and the inner container is signi. fi - cantly reduced. Another aspect of the present invention is directed to a com ^¬ puter program for conducting the method as previously described, 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 invent ion is described, in detail with reference to the drawings attached wherein

Figures la to 5b shows a first embodiment of an injection molding machine according to the invention and di fferent 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 perspect ive 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 to 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 mold, and

Figure 13 a fourth embodiment of the injection mold, by means of principle sketches . Figure la shows a principle view on an injection molding ma ^¬ chine 10i according to a first embodiment and Figure lb a sec ^¬ tion along the section plane Z-Z as defined in Figure la . For the sake of comprehensibility only the relevant part s of the in ject ion molding machine are shown, particularly in Figure la . The injection molding machine lOi is configured to produce a double wal led drinking vessel 12 having an outer container 14 and an inner container 16 ( see Figures 4b and 5b) .

The injection molding machine 10i comprises an injection mold 18 having a first mold portion 20 and a second mold portion 22. The first mold port ion 20 and the second mold portion 22 are facing each other and are axial ly movable along a cent ral axis A of the injection molding machine 10i . To this end the first mold portion 20 and the second mold port ion 22 are con ^¬ nected, to a number of guide rods 24. Moreover the injection molding machine 10i is equipped with driving means 26 for axi- ally moving the first mold portion 20 and the second mo1d por- tion 22 along the guide rods 24.

The first mold port ion 20 comprises one first cavity 28 and one second cavity 30 that are separately shown in Figures lc and Id, 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 in ject ing a joint material into the first cavity 28. The in- jection molding machine 10i 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 10i comprises an index plate 40 which is mounted to the second mo1d portion 22 and thus movable along the central axis A together with the second mold port ion 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 compri ses 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 lb 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 10i further compri ses a control unit 42 to coordinate the movements of the first mold port ion 20, the second mold portion 22 and the index plate 40 and to control the injection of the mo1 d material and the joint mate ^¬ rial into the respective cavities .

In the following the di fferent steps of a method will be ex- plained by which the injection molding machine 10i may be oper ^¬ ated . In Figure la and lb the injection molding machine 10i is opened and the index plate 40 is in a position in which neither the first core 46 nor the second core 48 are axial ly 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 insert ing 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 in jection gate 32 , thereby forming an outer container 14 (Figure 3b) , and into the second cavity 30 through the second cavity in jec ^¬ tion gate 34 , thereby forming an inner container 16 (not shown) . The mold material may be a thermoplast ic resin such as Tritan .

After the thermoplastic resin has cured the in jection molding machine 10 is opened by moving the first mo1d 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 act ivatable suet ion means 54 that produce a negative pressure acting between the inner container 16 and the second core 48 (se Figures 4b and 5b) . As a result the in ^¬ ner container 16 is removed from the second cavity 30 when the injection molding machine 10i is opened . In cont rast to that the outer container 14 remains in the first cavity 28. After that the index plate 40 is rotated, by 180° and the injection molding machine 10i is closed, again . When comparing the first cavity 28, e.g. shown in Figure 1 c, and the second cavity 30i, e.g. shown in Figure Id and/or when comparing the first core 46 and the second core 48, e.g. in Figure lb, it becomes clear that they are di fferent 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 a11 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 10i . For preventing such damages the first core 46 is mounted on the index piate 40 axially movable along the central axis A. The preload element 50 is forcing the first core 46i into a po ^¬ sition in which the first core 46i maximal ly protrudes from the index plate 40. This position is shown in Figures lb, 2b and 3b.

When the injection molding machine 10i is closed the first core 46 is axially moved against the force exerted, by the preload element 50. Concomitant ly 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 container 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 10i 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 raa- chine IO2 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 28i to 28 and four second cavities 30i to 304. The cavities 28, 30 are equal ^¬ ly arranged around the central, axis A so that they form an an ^¬ gle OC of 45° as shown in Figure 8. The first cavities 28i to 28 are grouped pairwise around the central axis A so that they form two first cavity pairs 28P1 and 28P2. The second cavities 30i to 304 are grouped pairwise around the cent ral 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 in ject ion gates 36 of the first cavities 28i to 28 are clearly visible . As shown m Figure 6 the index plate 40 compri ses two first cores 46i, 462 and four second cores 48 i to 484 · The two first cores 46i , 462 are arranged opposite to each other with refer ^¬ ence to the central axi s A. The two second cores 48 i , 482 are arranged adjacent to the first cores 46i and the two second cores 483 , 484 are arranged adjacent to the first core 462, the second cores 481 to 48 enclosing an angle of 45° with the ad ^¬ jacent first core 46ι , 462 with reference to the central axis A.

The second embodiment of the injection molding machine IO2 may be operated as fol lows . In Figure 8 the index plate 40 is placed in a position in which the first cores 461, 462 are in ^¬ serted into the first cavities 28 i , 283 and two of the second cores 48 i , 483 are inserted into the second cavities 302 and 304 whereas the remaining two second cores 482, 48 are inserted into the remaining first cavities 282, 284 · The mold material is injected, into the first cavities 28 i , 283 into which the first cores 461, 462 are inserted and into the second cavities 3Ο2, 304 into which the second cores 481, 48s are injected. It is noted that no mold material is injected into the remaining first cavit ies 282 , 28 into which the remaining two second cores 482, 484 are inserted. Consequently two outer containers 14 are produced in the first cavities 28 i , 283 and two inner containers 16 are produced in the second cavit ies 302 , 30 .

Now the injection mold 18 is opened and the first cores 461, 462 and the second cores 481 to 484 are removed from the re ^¬ spective first and second cavit ies 28 , 30. As already men ^¬ tioned with reference to the first embodiment of the injection mold 1 Oi the second cores 481 , 483 also withdraw the inner con ^¬ tainers 16 from the respective second cavities 302 , 304 whereas the outer containers 14 remain inside the first cavities 28i , 28 a . The index plate 40 is now rotated by 45° into a first ro ^¬ tary direction indicated by the arrow P (Figure 9 ) . The in jec- 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 28i, 283 compri sing the outer contain ^¬ ers 14. The first cores 461, 462 are now introduced into the first cavit ies 282, 284 and the two remaining second cores 482, 48 are now introduced into the two second cavities 30ι, 303 · The joint material is now injected into the first cavities 28i, 28 ₃ 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 282, 284 and the two second cavities 30ι, 3Ο3 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 posit ion shown in

Figure 11. The injection molding machine lOi is closed and by means of the second cores 482, 48 the two inner containers 16 are introduced into the first cavit ies 282, 284 comprising the outer containers 14. The joint material is injected into the first cavities 282, 284 through the further injection gates 36, thereby competing two double walled drinking vessels 12. At the same time mold material is injected into the first cavi ^¬ ties 28i and the second cavities 302, 304 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 lOi ac ^¬ cording to the second embodiment is operated two double walled drinking vessels 12 are completed and ejected each time the injection molding machine 10i is opened .

In Figure 12 a thi rd embodiment of an injection molding raa- chine IO3 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 OC of 120 ⁰ with ref ^¬ erence to the cent rai 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 lOi 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 IO3 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 injection molding machine IO3 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 counterelockwi se into a first rotational direction by 120 ⁰ 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 IO3 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 wal led drinking vessel 12. After curing the injection molding machine IO3 is opened and the completed double walled drinking vessel 12 is ejected. The index plate 40 is rotated by 120 ⁰ into a second rotat ional direction opposite the first rotat ional di ^¬ rection and the described steps are conducted again . In this embodiment one completed double wal led. drinking vesse1 12 is ejected every second time the injection molding machine IO3 is opened .

In Figure 13 a fourth embodiment of an injection molding ma- chine IO4 is shown by means of a principle sketch . The first mold portion 20 comprises in total four cavities, namely two first cavities 28i, 282 and two second cavities 30i, 302 · The cavities 28, 30 are equally arranged around the cent ral axis A. The first cavit ies 28i, 282 form a first cavity pai r 28P and the second cavities 30i, 302 form a second cavity pair 30P . The two first cavities 28i, 282 enclose an angle OC of 90 ⁰ with each other with reference to the central axis A. The same is true for the second cavities 30i, 302. The index plate 40 comprises one first core 46 and two second cores 48i, 482 , the two second cores 48i, 482 arranged opposite the cent ral axis A and thus enclosing an angle of 180° with reference to the cent ral axis A . The first core 46 is arranged in an angle of 90 ⁰ with regard to the second cores 48i, 482 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 4 81 is axially aligned with one of the second cavities 30 , in this case with the second cavity 30i . The other second core 482 is axially aligned with the other first cavity 28i. The in ^¬ jection molding machine IO4 is now closed and the mold material is injected into the first cavit 282 into which the first core 46 is introduced and into the second cavity 30i into which the second core 48i is introduced, thereby producing an outer con ^¬ tainer 14 and one inner container 16. After that the injection molding machine IO4 is opened and the index plate 40 rotated by 90 ⁰ countere lockwi se into a first rotational direction so that the second core 48i 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 28i . The other second core 482 is now axially aligned with the other second cavity 3Ο2 · The injection molding machine IO4 is now closed and the joint material is in jected into the first cavity 282 through the further injection gate 36, thereby complet ing one double walled, drinking ve s se1 12. At the same time the mold material is injected into the other first cavity 28i and the second cav ^¬ ity 3Ο2, thereby producing an outer container 14 and an inner container 16. The injection molding machine lOi is opened and the completed double walled drinking vessel 12 is ejected. The index plate 40 is rotated by 90 ⁰ 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 28i through the further injection gate 36, thereby complet ing a double wal led 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 30i into which the second core 48i 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 IO4 is opened . Reference list

10, 10i - IO4 injection molding machine

12 double walled drinking vessel 14 outer container

16 inner container

18 injection mo1 d

20 first mold portion

22 second mold portion

24 guide rod

26 driving means

28, 28i - 28 ₄ first cavity

30, 30i - 302 second cavity

32 first cavity injection gate 34 second cavity in ject ion gate

36 further injection gate

38 mani fold

40 index plate

42 control unit

44 rotary drive means

46, 461 - 462 first core

48, 48i - 484 second core

50 preload element

52 holding means

54 suction means

56 annular space

58 hollow space

60 additional cavity A central axis

P arrow