US3596311A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for isotropically stretching a plastics sheet
Assignee: Rhone Poulenc SA
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Filing: 1968-03-22
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Granted: 1971-08-03
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Expires: 1988-03-22
Abstract
Abstract The invention provides an apparatus for isotropically stretching a plastics sheet in which the sheet is gripped by a plurality of grippers, which are disposed in an array of a particular configuration, e.g. a circle or a square. In order to stretch the sheet the grippers are moved outwardly on screw-threaded rods which are geared together, e.g. by bevel gears, at a rate to maintain the same configuration.
Inventors
- 👤 Michel Salmon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 11:55
CPC Classifications
B; B29; B29C; B29C55/00; B29C55/02; B29C55/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
185 words
Apparatus for isotropically stretching a noncircular sheet of plastics, said apparatus comprising in combination: a. a central hollow hub; b. a rim coaxial with said central hollow hub; c. a plurality of separate screw-threaded rods arranged perpendicularly to the axis of said hollow hub and extending from said hollow hub to said rim, each rod being rotatable about its own axis; d. a plurality of slideways arranged perpendicularly to the axis of said hollow hub parallel to and in close proximity to said screw-threaded rods; e. a plurality of screw-threaded carriages, each threadably engaging on one of said screw-threaded rods, and slidable on one of said slideways; f. gripping means for gripping the sheet mounted on each carriage, said gripping means being disposed in an array of a particular configuration; and g. gearing, interconnecting said screw-threaded rods to cause rotation of each of the remaining rods, the pitches of the threads of said rods being such that at least one of said gripping means moves at a rate different from at least one of the remaining gripping means so as to maintain said configuration constant.
Claim 2
Dependent Claim
185 words
Apparatus for isotropically stretching a noncircular sheet of plastics, said apparatus comprising in combination: a. a central hollow hub; b. a rim coaxial with said central hollow hub; c. a plurality of separate screw-threaded rods arranged perpendicularly to the axis of said hollow hub and extending from said hollow hub to said rim, each rod being rotatable about its own axis; d. a plurality of slideways arranged perpendicularly to the axis of said hollow hub parallel to and in close proximity to said screw-threaded rods; e. a plurality of screw-threaded carriages, each threadably engaging on one of said screw-threaded rods, and slidable on one of said slideways; f. gripping means for gripping the sheet mounted on each carriage, said gripping means being disposed in an array of a particular configuration; and g. gearing, interconnecting said screw-threaded rods to cause rotation of each of the remaining rods, the pitches of the threads of said rods being such that at least one of said gripping means moves at a rate different from at least one of the remaining gripping means so as to maintain said configuration constant.
Claim 3
Dependent Claim
14 words
Apparatus as specified in claim 1, having at least five screw-threaded rods and carriages.
Claim 4
Dependent Claim
49 words
Apparatus as specified in claim 1, wherein a bevel gear is mounted at the inner end of each of said rods, wherein a single bevel gear is mounted on said hollow hub, and wherein said single bevel gear cooperates with each of the bevel gears mounted on said rods.
Claim 5
Dependent Claim
60 words
Apparatus as specified in claim 1, wherein a bevel gear is mounted at the inner end of each of said rods, and each of said bevel gears cooperates with the bevel gears on each of the adjacent rods, the pitch of the screw thread of each rod being oppositely directed to the pitch of the thread of each adjacent rod.
Claim 6
Dependent Claim
43 words
Apparatus as specified in claim 1, wherein a bevel gear is mounted at the inner end of each rod and wherein two idler gears are provided for each rod, each idler gear cooperating with the bevel gears on each of the adjacent rods.
Claim 7
Dependent Claim
29 words
Apparatus as specified in claim 1, wherein said configuration is a square, and the pitches of the threads of said rods are such that said square configuration is maintained.
References Cited (Backward Citations)
US2752630A
Cited
US2912716A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-02 | 1975-02-01 | 1975-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-02 | 1979-02-01 | 1979-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-02 | 1983-02-01 | 1983-08-03 | $7700.00 | Window Closed / Lapsed |