US 3,993,427 AGranted

Movable preform locator and blow air valve apparatus for a blow molding machine

AssigneeMonsanto Company

InventorsIvan L. Kauffman, Barry C. Owen

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Abstract

A preform locator and blow air valve apparatus, for use in a stretch pin assembly in a blow molding machine that produces hollow thermoplastic articles, which functions as a positive blow air shut-off valve means in the absence of a preform in a mold assembly. A tubular valve body is mounted in a stretch pin assembly, with a longitudinally movable blow air nozzle means slidably mounted in the valve body for carrying the preform and locating and sealing the preform against a shoulder in a mold assembly on a blow molding machine. A stretch pin is slidably mounted longitudinally through the blow air nozzle means for stretching a preform mounted on the nozzle means. A blow air passage means is operatively formed through the tubular valve body and blow air nozzle means for admitting blow air under pressure into a preform located in the mold assembly, by said blow air nozzle means, for blowing the preform into a finished article. The blow air nozzle means is moved by mechanical means into an initial position for loading a preform thereon. The blow air nozzle means is movable toward the mold assembly by either a mechanical means or a pneumatic means. The blow air nozzle means is moved a first distance toward the mold to locate and seal a preform in a mold assembly, and in the absence of a preform on the blow air nozzle means, the blow air nozzle means is moved a second distance, whereby it functions as a valve to close the blow air passage means to prevent loss of high pressure blow air and the resultant high noise levels.

Claims17

Dependent claims

In a blow molding machine having a mold assembly with a locating shoulder therein and a stretch pin assembly mounted in operative relation with said mold assembly, the combination comprising:

a. a tubular valve body in said stretch pin assembly;
b. a longitudinally movable blow air nozzle means slidably mounted in said valve body for carrying a preform and locating and sealing a preform against said shoulder in the mold assembly;
c. a blow molding stretch pin movably mounted longitudinally through said blow air nozzle means for stretching a preform mounted on said blow air nozzle means;
d. a blow air passage means operatively formed through said tubular valve body and blow air nozzle means for admitting blow air under pressure into a preform on said blow air nozzle means in said mold assembly for blowing the preform into a finished article;
e. means cooperating with said blow air nozzle means for longitudinally moving said blow air nozzle means in said tubular valve body in one direction into an initial position at which a preform is loaded onto the blow air nozzle means;
and
f. means operatively connected to said blow air nozzle means for longitudinally moving said blow air nozzle means in said tubular valve body in the opposite direction a first distance to locate and seal a preform carried thereon against said shoulder in the mold assembly, and for longitudinally moving said blow air nozzle means a second distance in said opposite direction beyond said first distance for shutting off said blow air passage means in the absence of a preform on the blow air nozzle means during operation of the blow modling machine.

4 more elements

Dependencies are inferred from the claim text.