Apparatus for making helically wound plastic tubing

Claim 2

IN AN APPARATUS FOR MAKING HELICALLY WOUND PLASTIC TUBING THE COMBINATION OF: A. MEANS FOR EXTRUDING A PLASTIC STRIP, B. WINDING MEANS FOR HELICALLY WINDING SAID STRIP ABOUT AN AXIS INTO TUBE WITH ONE EDGE OF EACH CONVOLUTION OVERLAPPING AN EDGE OF A PRECEDING CONVOLUTION, C. SAID WINDING MEANS COMPRISNG ROLLS CIRCUMFERENTIALLY SPACED APART AROUND AND EXTENDING IN THE DIRECTION OF SAID AXIS, D. SAID ROLLS BEGIN CANTED RELATIVE TO SAID AXIS AT ACUTE ANGLES E. MEANS FOR DRIVING SAID ROLLS, F. COLLING MEANS EXTENDING ALONG SAID AXIS AND SURROUNDED BY SAID ROLLS OR APPLYING A LIQUID COOLANT TO SAID TUBE INTERNALLY THEREOF, AND G. SAID COOLING MEANS TERMINATING WITHIN SAID TUBE IN A DOWNSTREAM-DIRECTED SPRAY OPENING WHICH DIRECTS A JET OF COOLANT AGAINST THE INTERIOR OF SAID TUBE, DOWNSTREAM OF AND IN CLOSE PROXIMITY TO SAID WINDING MEANS, ONLY IN THE DOWNSTREAM DIRECTION TO ASSIST IN DISPLACING SAID TUBE AXIALLY OFF SAID WINDING MEANS, SAID ROLLS AND SAID JET CONSTITUTING THE SOLE MEANS FOR DISPLACING SAID TUBE AXIALLY OFF SAID WINDING MEANS.

Claim 3

In an apparatus for making helically wound plastic tubing, the combination of: a. means for extruding a plastic strip; b. winding means for helically winding said strip about an axis into a tube rotatable about said axis with one edge of each convolution overlapping an edge of a preceding convolution; c. said winding means comprising rolls circumferentially spaced apart around and extending in the direction of said axis; d. said rolls being canted relative to said axis at acute angles; e. means for driving said rolls; f. cooling means for applying a liquid coolant to said tube internally and externally thereof; g. buoying means downstream from said winding means for buoying up said tube in coolant to reduce frictional resistance to rotation thereof about its axis; h. said buoying means including a trough extending lengthwise of said tube and receiving said tube and coolant applied thereto; i. said buoying means including means in said trough for retaining coolant in the bottom thereof at a predetermined minimum level sufficient to buoy up said tube and thus reduce frictional resistance to rotation thereof about its axis; and i. said cooling means including within said tube a downstream-directed spray opening which directs a jet of coolant against the interior of said tube, downstream of and in close proximity to said winding means, only in the downstream direction to assist in displacing said tube axially off said winding means, said rolls and said jet constituting the sole means for displacing said tube axially off said winding means.

Claim 4

In an apparatus for making helically wound plastic tubing, the combination of: a. means for extruding a plastic strip; b. winding means for helically winding said strip about an axis into a tube rotatable about said axis with one edge of each convolution overlapping an edge of a preceding convolution; c. said winding means comprising rolls circumferentially spaced apart around and extending in the direction of said axis; d. said rolls being canted relative to said axis at acute angles; e. means for driving said rolls; f. cooling means for applying a liquid coolant to said tube internally and externally thereof; g. buoying means downstream from said winding means for buoying up said tube in coolant to reduce frictional resistance to rotation thereof about its axis; h. said buoying means including a trough extending lengthwise of said tube and receiving said tube and coolant applied thereto; i. said buoying means including means in said trough for retaining coolant in the bottom thereof at a predetermined minimum level sufficient to buoy up said tube and thus reduce frictional resistance to rotation thereof about its axis; and i. said cooling means including within said tube a downstream-directed spray opening which directs a jet of coolant against the interior of said tube, downstream of and in close proximity to said winding means, only in the downstream direction to assist in displacing said tube axially off said winding means, said rolls and said jet constituting the sole means for displacing said tube axially off said winding means.