Method for fastening an accesory in a plastic fuel tank

A method for stake-fastening an accessory onto a plastic fuel tank, whereby:

• the accessory is equipped with at least one orifice which passes completely through the accessory;
• at least some of the plastic of which the wall of the plastic fuel tank is made is melted to form molten plastic;
• some of the molten plastic is compressed against the orifice of said accessory such that the molten plastic flows through the orifice without becoming detached from the remainder of the molten plastic thereby forming protruding molten plastic;
• and
• the protruding molten plastic is shaped to provide a self-formed plastic rivet, and is left to form solidified plastic;
• wherein the accessory has an indentation on an outer portion of the accessory and around the orifice,
• the indentation around the orifice has a variable cross section shaped to ease flow of the molten plastic into the orifice as the molten plastic is compressed against the accessory and into the orifice,
• the size and shape of the orifice and/or of the solidified plastic are such that the accessory is mechanically fastened to the tank by at least some of the solidified plastic,
• the stake-fastening of the accessory occurs at the time of manufacture of the tank, and
• wherein said tank is manufactured by the blow-moulding of a split or at least a two-part parison using a mould comprising a core on which the accessory has been positioned and moulding cavities, said stake-fastening being performed during an initial closing of the mould by bringing said moulding cavities around the core, pressing the parison onto the moulding cavities, and preventing the slot or the edges of the parts of the parison from welding together, the mould being opened to remove the core before closing the mould again to blow the tank.