Parison forming head group with variable interaxial distance

A forming group for forming a plurality of tubular parisons made of plastic material for a blow-moulding machine, comprising:

• a support (230), fixed during use;
• a first forming head (10A) and a second forming head (10B) mounted on the support (230) in a position alongside each other in a longitudinal direction (X-X);
• wherein each forming head (10A,10B) is configured to dispense a tubular parison (1,2) made of plastic material along a respective vertical dispensing axis through a bottom dispensing mouth and comprises a respective inlet (322i) for entry of the plastic material to be dispensed into the forming head (10A,10B);
• a supply source for supplying the plastic material, in particular a common inlet (310a) for supplying the plastic material;
• a mover assembly, arranged and configured to move the forming heads (10A,10B) in translation towards/away from each other in the longitudinal direction (X-X) so as to vary the interaxial distance between the dispensing axes of the forming heads;
• and
• connection means which connect the plastic material supply source (310a) to the inlet of the first head (10A) and to the inlet of the second head (10B) and which are configured to maintain the connection upon variation of the interaxial distance between the forming heads (10A,10B) characterized in that the connection means comprise:
• a first duct (455) communicating with the supply source, in particular with the common inlet (310a), a first compensator joint (451) which connects the first duct (455) to the inlet of the first head (10A) and is configured to expand/retract upon variation of the interaxial distance between the dispensing axes of the forming heads, so as to maintain the connection between the plastic material supply source (310a) and the respective inlet of the forming head (10A, 10B);
• and/or
• a second duct (455) communicating with the supply source, in particular with the common inlet (310a), a second compensator joint (452) which connects the second duct (455) to the inlet of the second head (10A) and is configured to expand/retract upon variation of the interaxial distance between the dispensing axes of the forming heads, so as to maintain the connection between the plastic material supply source (310a) and the respective inlet of the forming head (10A, 10B).