Transforming station for transforming plastic parisons into plastic containers, wherein the transforming station has two side part supports for supporting side parts of a blow mould, and preferably has a base part support for supporting a base part of the blow mould, wherein these side parts and the base part of the blow mould together form a hollow space within which the plastic parisons can be transformed into the plastic containers by application of a free-flowing medium, wherein at least one of the two side part supports for opening and/or closing the blow mould is pivotable relative to the other side part with respect to a predetermined main axis, and wherein the transforming station has a locking mechanism in order in a closed state of the blow mould to lock a side part support with the other side part support, and wherein the locking mechanism has a second locking element which is pivotable with respect to a predetermined pivot axis and which interengages with a first locking element for locking the side parts. According to the invention at least one of the two locking elements has a first contact surface which is suitable to co-operate with a second contact surface of the first locking element during locking with the first locking element, wherein at least one of these contact surfaces is designed in such a way that in a pivoting operation of the second locking element with respect to the pivot axis in the direction of the first locking element the two side part supports are pushed towards one another.