Patent US3950466A successfully refreshed from Google Patents.
US3950466A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stabilising sleeve
Assignee: Imperial Chemical Industries Ltd
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Filing: 1973-07-19
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Granted: 1976-04-13
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Expires: 1993-07-19
Abstract
Abstract Method and apparatus for stabilising the position of a tubular film comprising an annular, gas-permeable arcuate sleeve through which a tubular film can be passed, and means to supply gaseous fluid under pressure inwardly through the sleeve to create a cushion of gas between the tubular film and sleeve. The arcuate sleeve is suitably used in combination with a primary air-ring.
Inventors
- 👤 Robin Hasler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:08
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/90; B29C48/907; B29C48/03; B29C48/09; B29C48/10; B29C48/901; B29C48/903; B29C48/001; B29C48/0018; B29C48/0019; B29C48/885; B29C48/91; B29C48/911; B29C48/9115; B29C48/912; B29C48/919
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
Means for stabilizing the position of a tubular film travelling in a given direction without mechanically contacting or damaging the film, said means comprising an annular sleeve through which the tubular film can be passed, said sleeve providing around the periphery of the tubular film a circumferentially continuous gas-permeable surface the internal diameter of which is gradually decreased to a minimum value and subsequently gradually increased in the direction of travel of the tubular film to provide adjacent the tubular film a convex arcuate gas-permeable surface which is uniformly curved throughout its length in the direction of travel of the tubular film, and means for supplying gas under pressure inwardly through said surface to create a cushion of gas between the tubular film and said surface.
Claim 2
Dependent Claim
126 words
Means for stabilizing the position of a tubular film travelling in a given direction without mechanically contacting or damaging the film, said means comprising an annular sleeve through which the tubular film can be passed, said sleeve providing around the periphery of the tubular film a circumferentially continuous gas-permeable surface the internal diameter of which is gradually decreased to a minimum value and subsequently gradually increased in the direction of travel of the tubular film to provide adjacent the tubular film a convex arcuate gas-permeable surface which is uniformly curved throughout its length in the direction of travel of the tubular film, and means for supplying gas under pressure inwardly through said surface to create a cushion of gas between the tubular film and said surface.
Claim 3
Dependent Claim
56 words
Means according to claim 1 wherein the radius of curvature, R, of the arcuate gas-permeable surface is such that Pc ≧ T/R, where Pc is the pressure in the gas cushion between the tubular film and sleeve, and T is the longitudinal tension in the film, Pc, T, and R being expressed in mutually consistent units.
Claim 4
Dependent Claim
43 words
Means according to claim 1 comprising means for directing a uniform supply of cooling fluid against the external surface of the tubular film, said directing means being disposed upstream of the annular sleeve in relation to the direction of travel of the film.
Claim 5
Dependent Claim
132 words
Means for stabilizing the position of a tubular film travelling in a given direction without mechanically contacting or damaging the film, said means comprising an annular, gas-permeable sleeve through which the tubular film can be passed, said sleeve comprising a plurality of discrete members each with a gas-permeable surface disposed circumferentially around the tubular film, each of said gas-permeable surfaces being uniformly curved throughout its length in the direction of travel of the film, and also in a direction normal thereto, whereby each of said surfaces presents a uniform convex curvature to the tubular film when viewed both in plan and in cross-sectional elevation, and means for supplying gas under pressure inwardly through each of said surfaces to create a cushion of gas between the tubular film and each of said surfaces.
Claim 6
Dependent Claim
132 words
Means for stabilizing the position of a tubular film travelling in a given direction without mechanically contacting or damaging the film, said means comprising an annular, gas-permeable sleeve through which the tubular film can be passed, said sleeve comprising a plurality of discrete members each with a gas-permeable surface disposed circumferentially around the tubular film, each of said gas-permeable surfaces being uniformly curved throughout its length in the direction of travel of the film, and also in a direction normal thereto, whereby each of said surfaces presents a uniform convex curvature to the tubular film when viewed both in plan and in cross-sectional elevation, and means for supplying gas under pressure inwardly through each of said surfaces to create a cushion of gas between the tubular film and each of said surfaces.
Claim 7
Independent Claim
217 words
A method of forming a tubular film comprising the steps of extruding a tube of a thermoplastic polymeric filmforming material, establishing the movement of said tube in a given direction, cooling said extruded tube while controlling the rate at which said tube is travelling, reheating said cooled tube to an orienting temperature, introducing transverse orientation into said reheated tube by inflating it to form a tubular film, stabilizing the position of said tubular film without contacting said tubular film with mechanical means and without inflicting damage thereto by passing said tubular film through an annular sleeve located around the periphery of said tubular film in the region in which said tubular film attains its maximum diameter, said sleeve providing adjacent the tubular film a circumferentially continuous gas-permeable convex arcuate surface which is uniformly curved throughout its length in the direction of travel of said tubular film, supporting said tubular film out of contact with said surface of said sleeve without completely collapsing said inflated tubular film by supplying gas inwardly through the arcuate surface of said sleeve to create a cushion of gas between said tubular film and said arcuate surface and introducing longitudinal orientation into said tubular film by collapsing and withdrawing said inflated tubular film at a rate greater than said controlled rate of travel.
Claim 8
Independent Claim
217 words
A method of forming a tubular film comprising the steps of extruding a tube of a thermoplastic polymeric filmforming material, establishing the movement of said tube in a given direction, cooling said extruded tube while controlling the rate at which said tube is travelling, reheating said cooled tube to an orienting temperature, introducing transverse orientation into said reheated tube by inflating it to form a tubular film, stabilizing the position of said tubular film without contacting said tubular film with mechanical means and without inflicting damage thereto by passing said tubular film through an annular sleeve located around the periphery of said tubular film in the region in which said tubular film attains its maximum diameter, said sleeve providing adjacent the tubular film a circumferentially continuous gas-permeable convex arcuate surface which is uniformly curved throughout its length in the direction of travel of said tubular film, supporting said tubular film out of contact with said surface of said sleeve without completely collapsing said inflated tubular film by supplying gas inwardly through the arcuate surface of said sleeve to create a cushion of gas between said tubular film and said arcuate surface and introducing longitudinal orientation into said tubular film by collapsing and withdrawing said inflated tubular film at a rate greater than said controlled rate of travel.
Claim 9
Dependent Claim
16 words
A method according to claim 5 comprising supplying cold gaseous fluid inwardly through the arcuate surface.
Claim 10
Dependent Claim
54 words
A method according to claim 5 comprising maintaining a pressure of gas Pc in the gas cushion such that the relationship Pc≧T/R is satisfied, where T is the longitudinal tension in the film and R is the radius of curvature of the arcuate surface, Pc, T, and R being expressed in mutually consistent units.
Claim 11
Dependent Claim
30 words
A method according to claim 5 comprising directing a uniform supply of cooling fluid against the external surface of the tubular film before passing the film into the annular sleeve.
Claim 12
Dependent Claim
25 words
A method according to claim 5 wherein said cooling is effected by withdrawing said extruded tube at a controlled rate over an internal cooling mandrel.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-04-13 | 1979-10-13 | 1980-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-04-13 | 1983-10-13 | 1984-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-04-13 | 1987-10-13 | 1988-04-13 | $7700.00 | Window Closed / Lapsed |