Hot melt dispenser and method of making its melt body

Abstract

In a dispenser or applicator of heat softenable material, a melt body has a generally conical melting chamber extending between an inlet and a relatively smaller outlet passage, at least one by-pass interconnected to the melting chamber by a plurality of spaced, radial bores arranged to conduct hot melt from successive outer 'layers' of the material as it is being progressively softened, reduced and liquefied in the chamber for flowing to the outlet, and at least one axial auxiliary channel extending between the outlet and the smaller end of the melting chamber for conducting the central core of the last-to-be melted end portion of the material. Preferably the body has a pair of by-passes, a pair of auxiliary channels, encloses a heater, and is of configuration facilitating its economical construction in one piece. The method aspect features casting or otherwise providing a one-piece melt body of a metal, such as an aluminum alloy, to provide a main conical melt chamber and a cavity for a heater, boring one or more by-passes in the casting from its outlet and toward its inlet end and substantially parallel and adjacent to at least a portion of the outer wall of the melt chamber, boring an axial auxiliary channel to interconnect the outlet to the smaller end of the melt chamber, drilling the casting radially to provide substantially aligned holes interconnecting a by-pass with the melt chamber, inserting an element for instance a plug or ball as by press-fitting in an outer end of each hole, and sealing the outer ends of said holes, preferably simultaneously, by swedging external metal of the casting in overlapping retentive relation to the exterior portions of the elements.