Method for forming and keeping molten the recessed area of a fabricated plastic product

Claim 1

In the blow-molding of plastic fabricated products for a subsequent engagement with a sub-assembly wherein the fabricated product has an outer portion integral with an internal recess portion, the recess portion being designed to embrace the sub-assembly, the method comprising: (a) closing a mold onto a molten parison of thermoplastic material; (b) forming a recess in the exterior wall of the enclosed parison having substantially the shape and exterior dimensions of the sub-assembly, said recessed portion having a roof and side wall portion; (c) maintaining the temperature of the recessed portion of the parison at a temperature sufficiently high to substantially inhibit the relaxation tendency of the thermoplastic material; (d) maintaining the recess at the above temperature while the remainder of the parison is inflated against the cooled walls of the mold and brought to its final form or substantially so; (e) removing the fabricated product from the blow-molding machine; (f) placing the fabricated product into embracing engagement with the sub-assembly while its recessed portion is still in a molten state; and (g) providing for the cooling of the fabricated product whereby the molten recessed portion shrinks and forms a tight union with the sub-assembly.