Blow needle assembly

In a needle assembly containing cylinder means and piston means carrying a hollow needle slidably reciprocable in said cylinder means, the improvement which comprises, in combination, means accessible through said needle for releasably securing said needle to said piston means including:

• A. a collet having a wedge-shaped end cooperable with walls of a central bore in a piston portion of the piston means and an axially extending through-passage containing a shoulder for the end face of said needle, said bore having a threaded section along its length;
• B. a locknut in said central bore rearward of said collet cooperable with the threaded section thereof and having a central opening therein;
• C. a wrench insertable in said opening through the hollow interior of said needle to advance said locknut in one direction against the collet to tightly close on a rear portion of said needle and to back said locknut off in the opposite direction to permit release of said needle.

In a split mold having an internal cavity, a needle assembly including a hollow blow needle, means for reciprocating said needle in a bore formed in a section of said split mold to puncture and expand in said cavity a clamped off portion of a tubular parison, the improvement which comprises means accessible through said needle for releasably securing said needle to said means for reciprocating it.