Process and a device for producing plastic cups by injection moulding

An injection moulding process for producing a plastic cup having a label-shaped enveloping sheet integrated in said plastic cup according to the inmould-labelling method, said process comprising the following steps:

• picking up an enveloping sheet by means of a suction holding mandrel for inserting said enveloping sheet into a female mould for a subsequent injection moulding process;
• opening an injection mould by moving the female mould and a male mould away from each other to an opening position, a controlled positioning arm displacing, in the course of this opening movement, the suction holding mandrel to a position where it extends coaxially with the male mould and the female mould in an interspace evolving between the male mould and the female mould when said male and female moulds are moved apart;
• removing the previously produced plastic cup from the male mould;
• transferring the enveloping sheet from the suction holding mandrel to the female mould and inserting it therein;
• coaxially moving the male mould and the female mould into one another until a closed injection mould is re-established, the controlled positioning arm removing, due to said closing movement, the suction holding mandrel from the interspace which is defined between the male mould and the female mould and which disappears as a result of said closing movement;
• injecting molten plastic into the closed injection mould, wherein, for inserting the enveloping sheet, at least one part of the female mould is advanced coaxially with the suction holding mandrel from the opening position of said female mould towards said suction holding mandrel, that the enveloping sheet is transferred from the suction holding mandrel to the advanced part of the female mould and inserted therein, and that the advanced part of the female mould is returned to the opening position of said female mould.