An injection-compression molding device for producing bottle preforms, comprising - a frame ; - at least one molding cavity fixed to the frame ; - at least one rod , connected to the frame so as to be capable of sliding with respect thereto; - at least one core , connected to the at least one rod so as to be capable of sliding therewith, adapted to be inserted into the at least one molding cavity defining a mold; - actuation means adapted to exert a mold closing force when the at least one core is inserted into the at least one molding cavity ; wherein there is provided a joint connecting the at least one core to the at least one rod , characterized in that said joint comprises - a first part integrally connected and coaxial to said at least one core and defining a cavity ; - a second part integrally connected and coaxial to said at least one rod and at least partially slidable in said cavity when the closing force is applied; - elastic means arranged in said cavity ; said first part being provided with an inner side surface ; said second part being provided with an outer side surface ; wherein, in a first configuration of the joint , in absence of the closing force, the outer side surface is kept in contact with the inner side surface , by the bias of said elastic means , whereby the at least one rod and the at least one core are kept coaxial to each other; and wherein, in a second configuration of the joint , in presence of the closing force, a clearance is provided between the outer side surface and the inner side surface , said elastic means being pressed by said second part , whereby the at least one rod is adapted to rotate with respect to the core . - a frame ; - at least one molding cavity fixed to the frame ; - at least one rod , connected to the frame so as to be capable of sliding with respect thereto; - at least one core , connected to the at least one rod so as to be capable of sliding therewith, adapted to be inserted into the at least one molding cavity defining a mold; - actuation means adapted to exert a mold closing force when the at least one core is inserted into the at least one molding cavity ; wherein there is provided a joint connecting the at least one core to the at least one rod , characterized in that said joint comprises - a first part integrally connected and coaxial to said at least one core and defining a cavity ; - a second part integrally connected and coaxial to said at least one rod and at least partially slidable in said cavity when the closing force is applied; - elastic means arranged in said cavity ; said first part being provided with an inner side surface ; said second part being provided with an outer side surface ; wherein, in a first configuration of the joint , in absence of the closing force, the outer side surface is kept in contact with the inner side surface , by the bias of said elastic means , whereby the at least one rod and the at least one core are kept coaxial to each other; and wherein, in a second configuration of the joint , in presence of the closing force, a clearance is provided between the outer side surface and the inner side surface , said elastic means being pressed by said second part , whereby the at least one rod is adapted to rotate with respect to the core . <EOS>