Injection apparatus for a hot-chamber die-cast machine

Abstract

An injection apparatus for a hot-chamber die-cast machine including a cylindrical sleeve; a plunger body slidingly movably disposed in the sleeve and having a circumferential groove on an outer cylindrical surface and passages extending from a pressurizing face to the groove. Divided seal rings fit loosely in the groove of the plunger body in such a manner that the divided rings are urged radially outwardly by the pressure of the molten metal in the sleeve through the passages when the plunger body is moved. The divided rings satisfy the following conditions: t.sup.3 .ltoreq.4.5.times.10.sup.2 (mm).times.D.sup.2 .times.P/E where t: thickness (mm) of the divided rings, E: Young's modulus (Pa) of the divided rings, D: inner diameter (mm) of the sleeve, and P: pressure (Pa) which should be exerted onto the molten metal when injected.

Dependencies are inferred from the claim text.