The present invention relates to a blow moulding machine. Such blow moulding machines are known from the prior art. They are used for expanding plastic preforms into plastic containers in particular by applying pressurised air. To this end a preform, which as a rule has been preheated is placed in the corresponding blow mould and is subsequently expanded by means of pressurised air against the internal wall of this blow mould. Here, these plastic preforms already have a finished thread and only the bottom and the central area are expanded by applying pressurised air.
The area immediately below the thread is therefore a relatively sensitive area, especially when the plastic preforms are also expanded by means of a stretching rod. It is therefore known from the prior art that blow moulds include cooling means in order to cool in particular the neck area of the plastic preform during the expansion process. As a rule, such blow moulds also have so-called neck plates, on the inside of which there are drilled cooling channels. A cooling medium flows through these cooling channels, which cooling medium cools the neck area of the plastic preform during a working operation.
The neck plate including these cooling channels and the corresponding coolant connections are located on the blow mould. In today's embodiment, said bores need to be introduced into the neck plate, as a result of which the neck plate becomes more complex to produce and cannot be standardised. Also, some of the bores will subsequently have to be closed with plugs, which may also lead to leaks. The neck plate continues to have a relatively great thickness due to the cooling bore diameter and the media connections. Also the geometry of these bores has to be accurately adapted to the respective cross section of the neck of the plastic preform. Apart from that, this embodiment is also largely dependent on the geometric conditions, the shape and the neck diameter. This is in conflict with an optimum design.
If, for example, the blow moulds are changed in the course of a change of the tooling set, it is also necessary to replace the corresponding neck cooling assembly at the same time. For this reason, in the case of a mould change, also the connections need to be actuated via couplings.
From WO 2009/081 027, a blow mould for producing thermoplastic containers and a blow moulding system having such a blow mould are known. Here, a neck plate is provided which is to effect a direct cooling of the plastic preform, but at the same time is supposed to achieve a thermal insulation from the blow mould by means of insulating bodies. This heat sink has here a coolant connection and is screwed onto the blow mould.
The present invention is therefore based on the object of simplifying such blow moulding machines in particular also in the case of a blow mould change.