Blow-molding apparatus

Abstract

Blow-molding apparatus for the fabrication of hollow bodies from thermoplastic material, wherein a pre-cast element positioned on a blow pipe receives its finished shape in a hollow mold by blowing compressed air through the pipe.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:.]. .Iadd.I claim:.Iaddend. 
     
       1. Blow-molding apparatus for the fabrication of a hollow body of thermoplastic material within a blow mold, the body being subsequently released from the mold, comprising: a. a conventional blow pipe (3) capable of providing a first stream of gas,   b. a guide (5) for selectively implanting the blow pipe into the mold and extracting the blow pipe from the mold before the body is released from the mold,   c. a gas-supplying member of simple construction (3') .[.mounted on the guide and.]. separate from the blow pipe, the member being capable of supplying a second stream of gas to the mold after the removal of the blow pipe,   .[.the guiding serving to move.]. the said member .Iadd.being movable .Iaddend.into and out of the mold, and   d. a valve system (9,10) for selectively directing gas to the blow pipe (3) and the member (3'), the blow pipe expanding the body of thermoplastic within the mold and the gas-supplying member maintaining a positive gas pressure within the body while it is allowed to cool.   
     
     
       2. Blow-molding apparatus as recited in claim 1, characterized by the fact that the supplying of compressed gas to the gas-supplying member (3') takes place during a removal of the blow pipe (3) from the blow mold (2).   
     
     
       3. Blow-molding apparatus as recited in claim 1, characterized by the fact that a pre-cast station (1) and the common guide (5) are provided and the pre-cast station (1) and the blow mold (2) are located so that the blow pipe (3) and the compressed gas-supplying member (3') are arranged on the common guide (5) and extend in a single direction from the common guide (5).   
     
     
       4. Blow-molding apparatus as recited in claim 3, characterized by the fact that the blow mold is provided with an opening, the gas-supplying member (3') is shaped to act as a gaging part and, after removal of the blow pipe (3), the member is moved into the opening in the blow mold (2). 
     
     
       5. Blow-molding apparatus as recited in claim 1, characterized by the fact that one pre-shape station (1b) and two blow molds (2) are provided and the blow pipe (3b) is arranged on a swingable device, while a separate gas-supplying member (3'b) is mounted for movement into and out of each of the blow molds (2b).   
     
     
       6. Blow-molding apparatus as recited in claim 1, characterized by the fact that the gas-supplying member (3') is rod shaped.