This invention relates to thermoplastic applicators, and especially to hand-held, adhesive rod-fed guns.
In the application just referred to, a melt body comprises a generally conic main melt chamber having an outlet at its smaller end, at least one manifold by-pass generally parallel to the chamber, and holes spaced along the chamber to bleed off material as melted to the by-pass. Another melt body designed for an adhesive extruder is disclosed in U.S. Pat. No. 3,776,426 issued in the name of Albert Newton, the construction there being such that transverse collecting grooves at spaced intervals enable liquefied material to exit from the melt chamber and through a manifold to a discharge end. Numerous other devices have hitherto been provided for applying hot melt, a recently disclosed gun being shown, for example, in U.S. Pat. No. 3,877,610.
When the adhesive melting and feeding means is to be manually wielded with deftness it is important that, even through extended periods of "on-and-off" use, the heft of the manually manipulated tool not become burdensome. Rod-feed adhesive supplying mechanisms with a control therefor are generally found advantageous and convenient, but because of their weight, their incorporation in hand guns dictates that special consideration be given to attaining the lowest melt body weight consistent with adequate flow capacity and highly efficient heat transfer for effecting progressive melting of the rod as it is advanced to the point of application.