Closure system for liquid injection apparatuses

Claim 1

A closure system for use in liquid injection apparatuses for interrupting the injection of liquids into cavities, in particular liquids under a relatively high pressure and/or at relatively high temperatures, like plastics which are injected into injection moulds via a liquid passage, defined by a central body (1), said closure system having a closure rod which can be retractably placed in a gating of the liquid passage, said liquid passage (2) extending in a bended manner, the closure rod (16) extending through a wall of the central body (1), said gating being located at a bend in said liquid passage, said bend being situated above cross-sectional termination of said liquid passage in said central body, said closure rod having cross-sectional dimensions which are substantially equal to the dimensions of said gating, the closure rod (16) being totally retracted from the liquid passage (2) so as to expose the latter completely, said central body (1) comprising two cylindrical chambers (10), in each of which a cam (12) is placed, said chambers being separated by a wall with a spindle opening, an intermediate shaft (11) extending through said opening and connecting the cams so that they rotate simultaneously, each cam having two cavities angularly spaced by approximately 90°, said cavities being defined by involute pressure areas (13), one of said cavities of said cam being coupled to the closure rod (16) and the other cavity of said cam being coupled to a pull rod (14), whereby rotation of shaft (11) simultaneously closes a plurality of liquid passages.