US3647339A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blowhead for making tubular plastics
Assignee: Windmoeller and Hoelscher KG
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Filing: 1970-01-13
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Granted: 1972-03-07
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Expires: 1990-01-13
Abstract
Abstract A blowhead for making tubular plastics film comprising a housing having a central aperture for installing special equipment, a lateral supply passage in the housing for the entry of molten plastics material, branch passages which branch from the supply passage and extend, each in its own direction, through 90* about an insert in the housing, are then shortly curved to divert the flow of plastics material axially of the blowhead against the direction in which film is blown, and then diverge constantly in the peripheral direction until they merge at positions at an end of the insert, recesses formed in the housing adjacent the end of the insert to direct the flow of plastics material over projecting surfaces provided on the end of the insert and into an annular passage leading to a nozzle orifice from which the plastics material is blown as a film, the projecting surfaces and recesses extending in the direction opposite to the film blowing direction such that, starting from the sharp curvatures, the flow path for the plastics material to the nozzle orifice has the same length in every angular direction of the diverging portions of the branch passages.
Inventors
- 👤 Hartmut Upmeier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:32
CPC Classifications
B; B29; B29C; B29C48/00; B29C48/25; B29C48/30; B29C48/32; B29C48/34; B29C48/03; B29C48/09; B29C48/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
195 words
A blowhead for making tubular plastics film, comprising a housing having a central aperture for installing special equipment, a lateral supply passage in the housing for the entry of molten plastics material, branch passages which branch from said supply passage and extend, each in its own direction, through 90* about an insert in the housing, are then sharply curved to divert the flow of plastics material axially of the blowhead against the direction in which film is blown, and then diverge constantly in the peripheral direction until they merge at positions at an end of said insert, recesses formed in the housing adjacent said end of the insert to direct the flow of plastics material over projecting surfaces provided on said end of the insert and into an annular passage leading to a nozzle orifice from which the plastics material is blown as a film, the said projecting surfaces and recesses extending in the direction opposite to the film blowing direction such that, starting from said sharp curvatures, the flow path for the plastics material to the nozzle orifice has the same length in every angular direction of the diverging portions of the branch passages.
Claim 2
Dependent Claim
195 words
A blowhead for making tubular plastics film, comprising a housing having a central aperture for installing special equipment, a lateral supply passage in the housing for the entry of molten plastics material, branch passages which branch from said supply passage and extend, each in its own direction, through 90* about an insert in the housing, are then sharply curved to divert the flow of plastics material axially of the blowhead against the direction in which film is blown, and then diverge constantly in the peripheral direction until they merge at positions at an end of said insert, recesses formed in the housing adjacent said end of the insert to direct the flow of plastics material over projecting surfaces provided on said end of the insert and into an annular passage leading to a nozzle orifice from which the plastics material is blown as a film, the said projecting surfaces and recesses extending in the direction opposite to the film blowing direction such that, starting from said sharp curvatures, the flow path for the plastics material to the nozzle orifice has the same length in every angular direction of the diverging portions of the branch passages.
Claim 3
Dependent Claim
20 words
A blowhead according to claim 1, wherein the branch passages are formed in a substantially frustoconical portion of the insert.
Claim 4
Dependent Claim
13 words
A blowhead according to claim 1, wherein there are two said branch passages.
Claim 5
Dependent Claim
98 words
A blowhead according to claim 1, wherein the projecting surfaces are formed by lips and wherein the crest line of each lip as viewed in a developed condition is substantially, constituted by the geometric locus of the midpoints of all imaginary straight lines drawn in the film blowing direction from a straight line joining the said merging positions to an arc whose center is the imaginary point of intersection of the sides of the diverging portion of the respective branch passage and whose radius is equal to the distance of said point of intersection from the merging positions.
Claim 6
Dependent Claim
45 words
A blowhead according to claim 1, wherein each branch passage is constantly reduced in width and increased in depth between the supply passage and the said sharp curvature so that at the sharp curvature the depth of the passage is at least double its width.
Claim 7
Dependent Claim
46 words
A blowhead according to claim 2, wherein the frustoconical portion of the insert diverges in the film blowing direction and the parts of the branch passages between the supply passage and the sharp curvature are inclined against the film blowing direction at an acute angle thereto.
Claim 8
Dependent Claim
25 words
A blowhead according to claim 1, wherein the part of the housing containing the said recesses is in the form of an axially adjustable ring.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |