Apparatus for reproducing perforated seamless tubular films by means of compressed air

Claim 3

Apparatus as claimed in claim 1 wherein the first series of openings open into an annular groove on the inner surface of said body, and said groove is engaged by an annular shoulder of a subjacent chamber, said means defining said chamber being rotatable and provided with a second series of openings positionable to coincide periodically with the openings of said first series on rotation of said chamber.

Claim 4

Apparatus as claimed in claim 2, wherein both series of openings have equal numbers of openings.

Claim 5

Apparatus as claimed in claim 2, wherein said first series of openings has twice as many openings as said second series.

Claim 6

Apparatus as claimed in claim 3, wherein the openings of said second series have at least the same diameter as the openings of said first series.

Claim 7

Apparatus as claimed in claim 4, wherein the openings of said second series have at least the same diameter as the openings of said first series.

Claim 8

Apparatus as claimed in claim 1, wherein said first series of openings are provided in a wall forming part of the chamber connected to the compressed gaseous fluid source, said chamber having an annular groove into which said openings lead, and a plate provided with a solid rib axially displaceable in this chamber, to engage said rib in said groove to periodically block said first series of openings.

Claim 9

Apparatus for producing a tube of a plastic material having perforated walls comprising, core means having external perforated walls with openings therein open to the atmosphere, said core means having means therein defining a chamber for receiving a fluid under pressure therein, means defining a flow path into said chamber for connection in operation to a source of fluid under pressure, means for continuously passing in operation a full-walled, thermoplastic tube longitudinally over said perforated walls in contact therewith and open to the atmosphere with said core means disposed internally of said tube, said walls comprising a tapered surface increased in diameter in a direction of travel of the tubular film and a transverse surface transverse to the tapered surface merging smoothly with said tapered surface immediately upstream thereof and over which said tube travels longitudinally open to the atmosphere, and perforation control means operable from externally of said core means for periodically closed and opening said openings to flow said fluid under pressure therethrough to develop perforations through said tube in areas thereof in registry with said openings while said tube is travelling longitudinally.

Claim 10

Apparatus for producing a tube of a plastic material having perforated walls comprising, core means having external perforated walls with openings therein open to the atmosphere, said core means having means therein defining a chamber for receiving a fluid under pressure therein, means defining a flow path into said chamber for connection in operation to a source of fluid under pressure, means for continuously passing in operation a full-walled, thermoplastic tube longitudinally over said perforated walls in contact therewith and open to the atmosphere with said core means disposed internally of said tube, said walls comprising a tapered surface increased in diameter in a direction of travel of the tubular film and a transverse surface transverse to the tapered surface merging smoothly with said tapered surface immediately upstream thereof and over which said tube travels longitudinally open to the atmosphere, and perforation control means operable from externally of said core means for periodically closed and opening said openings to flow said fluid under pressure therethrough to develop perforations through said tube in areas thereof in registry with said openings while said tube is travelling longitudinally.

Claim 11

Apparatus for producing a tube of a plastic material having perforated walls according to claim 8, in which said means for passing said full-walled tube of thermoplastic material over said core means comprises extruder means for extruding a seamless tube of thermoplastic material in a plastic state over said perforated walls and close adjacent to said openings.

Claim 12

Apparatus for producing a tube of a plastic material having perforated walls according to claim 9, in which said gaseous fluid comprises air.

Claim 13

Apparatus for producing a tube of a plastic material having perforated walls according to claim 9, in which said perforation control means comprises wall surfaces on said chamber having openings positionable in registry and out of registry with th first-mentioned openings, and means to rotate said chamber selectively to effect said registry.

Claim 14

Apparatus for producing a tube of a plastic material having perforated walls according to claim 9, in which said perforation control means comprises a plate movable to positions for masking and unmasking said openings.

Claim 15

Apparatus for producing a tube for a plastic material having perforated walls according to claim 9, in which said openings are arranged in a circle.

Claim 16

Apparatus for perforating a tubular film of plastic material before setting thereof comprising, core means inserted in operation into a full-walled tube of thermoplastic film in a plastic state for effecting perforations into said tube of thermoplastic film, said core having a chamber therein for receiving a gaseous fluid therein under pressure, said core means having a diverging surface open to the atmosphere over which said tube of thermoplastic film is advanced in operation longitudinally in contact therewith, and open to the atmosphere, said diverging surface increasing in transverse dimension in the direction of travel of said tube, a transverse surface transverse to the tapered surface merging smoothly with said diverging surface immediately upstream thereof and over which said tube travels longitudinally and open to the atmosphere, said transverse surface having openings therein immediately adjacent an area of merging of the surfaces and in communication with said chamber, means defining a path for providing a gaseous fluid under pressure into said chamber, perforation perforations control means including means operable from externally of said tube for periodically obstructing said openings from internally of core means to flow said fluid under pressure therethrough to develop perforations through said full-walled tube areas in registry with said openings.

Claim 17

Apparatus for perforating a tubular film of plastic material before setting thereof comprising, core means inserted in operation into a full-walled tube of thermoplastic film in a plastic state for effecting perforations into said tube of thermoplastic film, said core having a chamber therein for receiving a gaseous fluid therein under pressure, said core means having a diverging surface open to the atmosphere over which said tube of thermoplastic film is advanced in operation longitudinally in contact therewith, and open to the atmosphere, said diverging surface increasing in transverse dimension in the direction of travel of said tube, a transverse surface transverse to the tapered surface merging smoothly with said diverging surface immediately upstream thereof and over which said tube travels longitudinally and open to the atmosphere, said transverse surface having openings therein immediately adjacent an area of merging of the surfaces and in communication with said chamber, means defining a path for providing a gaseous fluid under pressure into said chamber, perforation perforations control means including means operable from externally of said tube for periodically obstructing said openings from internally of core means to flow said fluid under pressure therethrough to develop perforations through said full-walled tube areas in registry with said openings.

Claim 18

Apparatus for perforating a tubular film of plastic material before setting thereof according to claim 14, including an extruder means circumferentially of said core means for extruding said full-walled tube of thermoplastic film upstream of and close adjacent to said openings over which said full-walled tube of film advances longitudinally.

Claim 19

Apparatus for producing a perforated seamless thermoplastic tubular film comprising, extruder means for extruding during operation a thermoplastic, full-walled, tubular film open to the atmosphere, core means within the extruded full-walled tubular film during operation having walls having perforations open to the atmosphere over which said full-walled tubular film travels longitudinally in direct contact therewith, said walls having surfaces changing the direction of travel longitudinally of said tubular film and including a diverging surface for expanding it during travel thereof, said perforations being disposed immediately upstream of said diverging surface defining flow paths slanted relative to the axis of the tubular film in a direction toward the direction of travel of the tubular films over said walls, perforation control means operable for periodically closing and opening said perforations to flow air under pressure therethrough to develop perforations through said full-walled tube in areas thereof in registry with said perforations while said tube is travelling longitudinally, and means for connecting said core means to a source of air under pressure.

Claim 20

Apparatus for producing a perforated seamless thermoplastic tubular film comprising, extruder means for extruding during operation a thermoplastic, full-walled, tubular film open to the atmosphere, core means within the extruded full-walled tubular film during operation having walls having perforations open to the atmosphere over which said full-walled tubular film travels longitudinally in direct contact therewith, said walls having surfaces changing the direction of travel longitudinally of said tubular film and including a diverging surface for expanding it during travel thereof, said perforations being disposed immediately upstream of said diverging surface defining flow paths slanted relative to the axis of the tubular film in a direction toward the direction of travel of the tubular films over said walls, perforation control means operable for periodically closing and opening said perforations to flow air under pressure therethrough to develop perforations through said full-walled tube in areas thereof in registry with said perforations while said tube is travelling longitudinally, and means for connecting said core means to a source of air under pressure.