Patent US4144008A successfully refreshed from Google Patents.
US4144008A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for stretching a tubularly-formed sheet of thermoplastic material
Assignee: Biax Fiberfilm Corp
•
Filing: 1977-02-09
•
Granted: 1979-03-13
•
Expires: 1997-02-09
Abstract
Abstract There is described in a preferred embodiment of the present invention, a process and apparatus for bi-axially stretching a tubularly-formed sheet of thermoplastic material in a first station and a plurality of second stations wherein the first and second stations are provided with sets of rolls having generally sinosoidally-shaped grooves perpendicular and parallel, respectively, to the axis of each set of rolls to produce bags of improved strip tensile breaking length.
Inventors
- 👤 Eckhard C. A. Schwarz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:14
CPC Classifications
D; D04; D04H; D04H1/00; Y; Y10; Y10S; Y10S425/00; Y10S425/20; Y10S425/201
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
300 words
An apparatus for producing thermoplastic bags which comprises: (a) means for extruding a tube of orientable polymeric material; (b) means for forming said tube into a sheet; (c) means for heat sealing said sheet at preselected portions thereof; (d) a first station means for stretching incremental portions of said sheet in a first direction and including a first set of interdigitating rollers formed with grooves, said first set of interdigitating rollers forming a nip therebetween; (e) first regulator means for controlling the velocity of introduction of said sheet into said nip of said first set of interdigitating rollers to assume and maintain said velocity substantially identical to the surface velocity of said first set of interdigitating rollers to prevent slipping of said sheet and thereby stretch incremental portions of said sheet by a deflection of said sheet into said grooves; (f) a first take-up means for elongating said sheet in said first direction upon withdrawal of said sheet from said first set of interdigitating rollers; (g) a second station means for stretching incremental portions of said sheet in a second direction and including a second set of interdigitating rollers formed with grooves, said second set of interdigitating rollers forming a nip therebetween; (h) a second regulator means for controlling the velocity of introduction of said sheet into said nip of said second set of interdigitating rollers to assume and maintain said velocity substantially identical to the surface velocity of said second set of interdigitating rollers to prevent slipping of said sheet and thereby stretch incremental portions of said sheet by a deflection of said sheet into said grooves. (i) a second take-up means for elongating said sheet in said second direction upon withdrawal of said sheet from said second set of interdigitating rollers; and (j) means for receiving said sheet.
Claim 2
Independent Claim
300 words
An apparatus for producing thermoplastic bags which comprises: (a) means for extruding a tube of orientable polymeric material; (b) means for forming said tube into a sheet; (c) means for heat sealing said sheet at preselected portions thereof; (d) a first station means for stretching incremental portions of said sheet in a first direction and including a first set of interdigitating rollers formed with grooves, said first set of interdigitating rollers forming a nip therebetween; (e) first regulator means for controlling the velocity of introduction of said sheet into said nip of said first set of interdigitating rollers to assume and maintain said velocity substantially identical to the surface velocity of said first set of interdigitating rollers to prevent slipping of said sheet and thereby stretch incremental portions of said sheet by a deflection of said sheet into said grooves; (f) a first take-up means for elongating said sheet in said first direction upon withdrawal of said sheet from said first set of interdigitating rollers; (g) a second station means for stretching incremental portions of said sheet in a second direction and including a second set of interdigitating rollers formed with grooves, said second set of interdigitating rollers forming a nip therebetween; (h) a second regulator means for controlling the velocity of introduction of said sheet into said nip of said second set of interdigitating rollers to assume and maintain said velocity substantially identical to the surface velocity of said second set of interdigitating rollers to prevent slipping of said sheet and thereby stretch incremental portions of said sheet by a deflection of said sheet into said grooves. (i) a second take-up means for elongating said sheet in said second direction upon withdrawal of said sheet from said second set of interdigitating rollers; and (j) means for receiving said sheet.
Claim 3
Dependent Claim
35 words
The apparatus as defined in claim 1 wherein said first and second set of interdigitating rollers are formed with grooves which are perpendicular and parallel, respectively, to said first and second sets of interdigitating rollers.
Claim 4
Dependent Claim
33 words
The apparatus as defined in claim 2 wherein said second take-up means are press rollers operated at a rotational velocity proportional to the draw ratio effected in said second set of interdigitating rollers.
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) | 1982-03-12 | 1982-09-11 | 1983-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-12 | 1986-09-11 | 1987-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-12 | 1990-09-11 | 1991-03-13 | $7700.00 | Window Closed / Lapsed |