Multi-part blow-mold for making hollow bodies from thermoplastic material

Claim 1

In a multi-part blow-mold, for making hollow bodies from thermoplastic material, having cooling spaces arranged in the blow-mold parts, for circulation of a coolant, and having a negatiVe innerwall corresponding to the outer contour of the hollow body to be formed, the improvement comprising, in combination, each blow-mold part including a box-type metal body frame, having relatively thick walls, and a thin-walled metal shell insert presenting the negative contour, the wall thickness of said insert being very substantially less than that of said body frame; each insert being secured to the associated body frame and closing it off internally; each insert and the associated body frame defining a respective cooling chamber of substantially the height of the insert; each insert consisting of a sheet metal shell; the metal body frame parts conjointly defining at respective opposite ends of the mold, a centering aperture for a shoulder insert and a centering aperture for a botton insert; a shoulder insert and a bottom insert inserted into each respective aperture; said shoulder insert and said bottom insert being formed with recesses in their inner surfaces in which the shell insert ends are sealingly engaged; guide plates dividing each cooling chamber for coolant circulation; said guide plates being shorter than the associated cooling chamber terminating, alternately, at substantially the level of said shoulder insert and at substantially the level of said bottom insert, whereby openings, for the coolant flow, are formed alternately adjacent the shoulder insert and the bottom insert; said guide plates being parallel to and spaced from each other and inserted in respective longitudinal grooves of each metal body frame, and extending inwardly to the associated thin walled metal shell insert and functioning as a support for the associated thin walled metal shell insert.