Apparatus for the manufacture of plastic tubing of special cross-sectional configuration

Claim 2

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distant from said extrusion means and reenters said molding path at a point closer to said extrusion means including means for guiding each mold half on an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises means for guiding each mold half about said arcuate path in such manner that the outer forward edge of said mold half defines a curve with a smaller radius than the radius of the curve defined by the outer rearward edge of said mold half and means for closing the halves of the pair of mold halves together while the leading portion of the moLd halves is passing a line drawn between the centers of curvature of said arcuate paths.

Claim 3

An improved apparatus claimed in claim 1 including a multiplicity of mold half pairs divided into right mold halves and left mold halves respectively.

Claim 4

An improved apparatus claimed in claim 2, wherein all of said right and left mold halves respectively are joined together along a continuous curve.

Claim 5

An improved apparatus claimed in claim 3 including pulley means within each of said continuous curves engaged with said halves in a driving relation.

Claim 6

An improved apparatus claimed in claim 3 including carrier means on said recycle path means wherein each of said mold halves is joined to said carrier means at a point forward of the center of said mold halves.

Claim 7

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point different from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement wherein there are a multiplicity of mold half pairs divided into right mold halves and left mold halves wherein all of the right and left mold halves, respectively, are joined together along a continuous curve, said apparatus comprising carrier means on said recycling path means wherein each of said mold halves is joined to said carrier means at a point forward of the center of said mold halves wherein said mold halves have recesses adjacent the point where such are joined to said carrier means which recesses are adapted to contact drive pulley means within each of said continuous curves.

Claim 8

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point different from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement wherein there are a multiplicity of mold half pairs divided into right mold halves and left mold halves wherein all of the right and left mold halves, respectively, are joined together along a continuous curve, said apparatus comprising carrier means on said recycling path means wherein each of said mold halves is joined to said carrier means at a point forward of the center of said mold halves wherein said mold halves have recesses adjacent the point where such are joined to said carrier means which recesses are adapted to contact drive pulley means within each of said continuous curves.

Claim 9

An improved apparatus claimed in claim 6 wherein the radii of curvature of said recesses is not greater than the radius of curvature of the periphery of said drive pulley.

Claim 10

An improved apparatus as claimed in claim 6 including the apexes of said recesses are positioned rearwardly of said joining point.

Claim 11

An improved apparatus as claimed in claim 6 including second recess means disposed on the side of said mold halves directed toward said pulley means which second recess means engages with said mold closing means.

Claim 12

An improved apparatus as claimed in claim 2 wherein said mold closing means is a roller means.

Claim 13

An improved apparatus as claimed in claim 9, including third recess means disposed on the rearwardly directed end of said mold halves which third recess means engages said carrier means.

Claim 14

An improved apparatus as claimed in claim 2 including link means attaching said left and right mold halves together respectively.

Claim 15

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distance from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises means for guiding each mold half about said arcuate path in such a manner that the outer forward edge of said mold half defines a curve with a smaller radius than the radius of the curve defined by the outer rearward edge of said mold, said apparatus including a pair of mold half pairs divided into right mold halves and left mold halves, respectively, said apparatus including link means attached to said left and right mold halves together, respectively, wherein said links are about half as thick at their point of attachment to said mold halves as they are in other areas and wherein said links overlap each other at said point of attachment.

Claim 16

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distance from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises means for guiding each mold half about said arcuate path in such a manner that the outer forward edge of said mold half defines a curve with a smaller radius than the radius of the curve defined by the outer rearward edge of said mold, said apparatus including a pair of mold half pairs divided into right mold halves and left mold halves, respectively, said apparatus including link means attached to said left and right mold halves together, respectively, wherein said links are about half as thick at their point of attachment to said mold halves as they are in other areas and wherein said links overlap each other at said point of attachment.

Claim 17

An improved apparatus as claimed in claim 11, wherein said carrier means is link means disposed in said third recesses.

Claim 18

An improved apparatus as claimed in claim 10, wherein said apparatus comprises a pair of closing rolls which urge said halves of mold pairs toward one another in closing position and said apparatus further comprises a series of opposed rolls comprising right rolls and left rolls respectively wherein one of said right or left rolls is disposed a fixed distance from said mold path and wherein the other of said rolls is spring loaded and disposed a variable distance from said mold path, wherein said spring loading is sufficient to maintain snug contact between closed mold halves, said series of right rolls and left rolls being disposed along the molding path, one series being fixedly disposed along one side and the other being mounted along the other side on a common support which is spring loaded and pressed against said mold path.

Claim 19

An improved apparatus as claimed in claim 15, including right and left guide rail means engaging said right and left roll means respectively.

Claim 20

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distant from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises a multiplicity of mold half pairs divided into right mold halves and left mold halves, respectively, including adjustable contactor means associated with said mold path and said mold halves operative to shut down said driving pulley in response to improper alignment of said mold halves.

Claim 21

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distant from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises a multiplicity of mold half pairs divided into right mold halves and left mold halves, respectively, including adjustable contactor means associated with said mold path and said mold halves operative to shut down said driving pulley in response to improper alignment of said mold halves.

Claim 22

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distant from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises at least one bore in the mold halves for passage of coolant therethrough and means to feed and recover coolant thereto and therefrom respectively including base plate means and apertures therein.

Claim 23

In an apparatus for forming transversely corrugated thermoplastic tubing which comprises tubing extrusion means; at least one pair of mold halves, a molding path aligned with said extrusion means, recycling path means partially aligned with said molding path through which each of said mold halves leaves said molding path at a point distant from said extrusion means and reenters said molding path at a point closer to said extrusion means including an arcuate path immediately preceding said molding path reentry, and means for closing said mold halves about a thermoplastic tubing extruded from said extrusion means; the improvement which comprises at least one bore in the mold halves for passage of coolant therethrough and means to feed and recover coolant thereto and therefrom respectively including base plate means and apertures therein.

Claim 24

An improved apparatus as claimed in claim 18, including reducing valve means in said coolant feed means whereby coolant in said mold halves is under vacuum.