US3749540A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for air-cooling a tubular plastics film blown by a blowhead
Assignee: Windmoeller and Hoelscher KG
•
Filing: 1970-09-29
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Granted: 1973-07-31
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Expires: 1990-09-29
Abstract
Abstract An apparatus for air cooling a tubular plastic film blown by a blowhead to introduce cooling air to within the tubular film at a pressure so that the interior film pressure exceeds the blowing pressure necessary for stretching the film in its plastic state. Mechanical supporting elements of low coefficient of friction externally support the tubular film issuing from the blowhead at least up to a position where the film has solidified.
Inventors
- 👤 H Upmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:17
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/88; B29C48/90; B29C48/908; B29C48/03; B29C48/09; B29C48/10; B29C48/885; B29C48/89; B29C48/901; B29C48/903; B29C48/907; B29C48/911; B29C48/9115; B29C48/912
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
174 words
Apparatus for air-cooling a tubular plastics film blown by a blowhead, comprising an inlet and an outlet passageway passing through the blowhead to maintain a throughput of cooling air within the tubular film at a pressure that exceeds the pressure necessary for stretching the film in its plastic state, and a plurality of superposed spaced supporting rings of low coefficient of friction for externally supporting the tubular film issuing from the blowhead at least up to a position where the film has solidified, each of said supporting rings comprising a plurality of components each of which is formed with a curved portion and straight end portions and is adjustable within limits radially of the tubular film, the radius of curvature of the curved portion corresponding to the radius that the tubular film would receive if the associated component were in a middle position between its limits of adjustment, and wherein the angle subtended between the straight end portions of each component is 15* to 20* larger than the sector angle of the curved portion.
Claim 2
Dependent Claim
174 words
Apparatus for air-cooling a tubular plastics film blown by a blowhead, comprising an inlet and an outlet passageway passing through the blowhead to maintain a throughput of cooling air within the tubular film at a pressure that exceeds the pressure necessary for stretching the film in its plastic state, and a plurality of superposed spaced supporting rings of low coefficient of friction for externally supporting the tubular film issuing from the blowhead at least up to a position where the film has solidified, each of said supporting rings comprising a plurality of components each of which is formed with a curved portion and straight end portions and is adjustable within limits radially of the tubular film, the radius of curvature of the curved portion corresponding to the radius that the tubular film would receive if the associated component were in a middle position between its limits of adjustment, and wherein the angle subtended between the straight end portions of each component is 15* to 20* larger than the sector angle of the curved portion.
Claim 3
Dependent Claim
43 words
Apparatus according to claim 1, wherein the superposed supporting rings are spaced from one another in such a way that exterior cooling air issuing from a cooling ring provided on the blowhead has substantially unimpeded access to the exterior of the tubular film.
Claim 4
Dependent Claim
56 words
Apparatus according to claim 1, wherein the tubular film is supported from the blowhead nozzle up to beyond the solidifying position by the said plurality of superposed spaced supporting rings which are adjustable both in their diameter and in respect of their spacing from one another to conform to the desired tubular shape of the film.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 1, wherein said supporting rings are provided with easily rotatable sleeves of a heat-resistant non-adhesive material such as polytetrafluoroethylene.
Claim 6
Dependent Claim
13 words
Apparatus according to claim 4, wherein the sleeves comprise independently rotatable juxtaposed rolls.
Claim 7
Dependent Claim
23 words
Apparatus according claim 1 in combination with a blowhead having a lateral inlet for molten plastics material from which the film is formed.
Claim 8
Dependent Claim
16 words
Apparatus according to claim 1, wherein each supporting ring comprises an even number of said components.
Claim 9
Dependent Claim
20 words
Apparatus accOrding to claim 1, wherein the components of each supporting ring are simultaneously radially adjustable in the same sense.
Claim 10
Dependent Claim
59 words
Apparatus according to claim 1, wherein some of the supporting rings together define a substantially cylindrical bounding surface for governing the ultimate radius of the solidified tubular film and the other supporting rings are disposed adjacent the blowhead, together define a substantially frustoconical bounding surface for the film and are adjustable in unison by means of a parallelogram linkage.
Claim 11
Dependent Claim
19 words
Apparatus according to any one of claims 1, wherein the supporting rings comprise wires having an easily rotatable covering.
Claim 12
Dependent Claim
25 words
Apparatus according to claim 1, including further supporting rings beyond the solidifying position, said further rings being hollow for the passage of a cooling medium.
Claim 13
Dependent Claim
28 words
Apparatus according to claim 1, wherein the supporting rings are carried by a frame which is continuously or reversingly rotatable about the longitudinal axis of the tubular film.
Claim 14
Dependent Claim
23 words
Apparatus according to claim 1, wherein the supporting rings are slightly inclined to one side of a radial plane of the tubular film.
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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) | 1976-07-30 | 1977-01-29 | 1977-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-30 | 1981-01-29 | 1981-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-30 | 1985-01-29 | 1985-07-31 | $7700.00 | Window Closed / Lapsed |