Apparatus for injecting air or gas into a tubular film bubble
AssigneeWindmoller & Holscher
InventorsFriedhelm Brinkmeier, Heinrich Frommeyer
Life of this patent
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Abstract
To maintain an air or gas bubble forming in a moving tube of plastics material between pairs of squeeze rollers, an air or gas injecting needle is mounted to pivot substantially in a plane containing the centerline of the tube. The needle pierces the tube wall of the bubble when in one rotary position, moves with the tube while pivoting through an arc depending on the depth of needle penetration and is withdrawn from the bubble in a second rotary position.
Claims12
Apparatus for injecting a compressed gas, by an injection needle, into a bubble formed by squeeze rollers in a moving web of tubular film, said apparatus comprising:
- an injection means adapted for injection of a compressed gas into said bubble, said injection means is pivotable about an axis transverse to a plane passing through a centerline of said tubular web;
- moving means for moving said injection means between a first position during which said injection means extends and pierces said bubble and a second position during which said injection means retracts from said bubble;
- means for releasing said compressed gas at said first position and halting the release of said compressed gas at said second position;
- and
- means for accelerating said injection means to a circumferential speed corresponding to the speed of said tubular film.
Dependencies are inferred from the claim text.