US3812769A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of plastic bags
Assignee: NATIONAL TRUST Co A TRUST Co OF ONTARIO
•
Filing: 1972-12-07
•
Granted: 1974-05-28
•
Expires: 1992-12-07
Abstract
Abstract An apparatus and method for the manufacture of bags from a length of plastic film by folding inward and sealing together the longitudinal margins of the film to form a tube, and then sealing the tube transversely. The apparatus can be employed to manufacture valve bags having the valve formed by an unsealed portion of the longitudinal margins of the length of film. The length of film may be constituted by multiple plies of film.
Inventors
- 👤 J Barnes
- 👤 E Rowley
- 👤 C Thomas
- 👤 E Bizon
- 👤 C Robertson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:14
CPC Classifications
B; B31; B31B; B31B70/00; B31B70/74; B31B70/81; B31B70/84; B31B70/855; B31B2160/00; B31B2160/10; B31B70/26; B31B70/36
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
191 words
An apparatus for the manufacture of plastic valve bags in a continuous manner comprising 1. means for providing a single or multiple ply length of plastic film, 2. means for infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve, 3. means for heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube, 4. means for heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal, 5. means for heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and 6. means for severing the sealed tube transversely at the position of the transverse seal, thus severing consecutively produced bags.
Claim 2
Independent Claim
191 words
An apparatus for the manufacture of plastic valve bags in a continuous manner comprising 1. means for providing a single or multiple ply length of plastic film, 2. means for infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve, 3. means for heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube, 4. means for heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal, 5. means for heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and 6. means for severing the sealed tube transversely at the position of the transverse seal, thus severing consecutively produced bags.
Claim 3
Dependent Claim
31 words
means for infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve,
Claim 4
Dependent Claim
31 words
means for infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve,
Claim 5
Dependent Claim
41 words
An apparatus as claimed in claim 1 adapted to heat-seal together the tube transversely at positions corresponding to both borders of the transverse severing position in the form of a double seal, thus forming end closures for two consecutively produced bags.
Claim 6
Dependent Claim
29 words
infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve,
Claim 7
Dependent Claim
29 words
infolding both longitudinal margins of the length of film so that the margins lie in overlapped contact, the overlapped portions being adequate to form the walls of a valve,
Claim 8
Dependent Claim
40 words
heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube,
Claim 9
Dependent Claim
40 words
heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube,
Claim 10
Dependent Claim
42 words
means for heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube,
Claim 11
Dependent Claim
42 words
means for heat-sealing together the overlapped margins of the film by a longitudinal seal running along a line parallel to the longitudinal axis of the length of film for a distance less than the length of a bag to form a tube,
Claim 12
Dependent Claim
64 words
An apparatus as claimed in claim 1 wherein the length of film is a length of flattened tubing having its margins constituted by the tubing folds and there is provided (a) means for slitting longitudinally one margin of said tubing at a position corresponding to the inner wall of the valve, and (b) means for unfolding the tubing fold adjacent to the slit margin.
Claim 13
Dependent Claim
39 words
An apparatus as claimed in claim 1 wherein there is provided means for folding longitudinally a length of single-ply film to form a two-ply length of film having one border constituted by a fold, the other border being open.
Claim 14
Dependent Claim
22 words
means for heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal,
Claim 15
Dependent Claim
22 words
means for heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal,
Claim 16
Dependent Claim
20 words
heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal,
Claim 17
Dependent Claim
20 words
heat-sealing together the overlapped margins of the film by a transverse seal located at one end of the longitudinal seal,
Claim 18
Dependent Claim
43 words
heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and
Claim 19
Dependent Claim
43 words
heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and
Claim 20
Dependent Claim
45 words
means for heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and
Claim 21
Dependent Claim
45 words
means for heat-sealing together the tube, including the overlapped margins of the film, in a transverse seal at a position adjacent to the second end of the longitudinal seal, the unsealed portions of the margins of the film forming the walls of a valve, and
Claim 22
Dependent Claim
43 words
An apparatus as claimed in claim 1 wherein the means for provIding a multiple ply length of plastic film comprises a plurality of rolls of film adapted to feed a plurality of superimposed plies of film to the infolding means of the apparatus.
Claim 23
Dependent Claim
19 words
means for severing the sealed tube transversely at the position of the transverse seal, thus severing consecutively produced bags.
Claim 24
Dependent Claim
19 words
means for severing the sealed tube transversely at the position of the transverse seal, thus severing consecutively produced bags.
Claim 25
Dependent Claim
64 words
An apparatus as claimed in claim 1 wherein the means for infolding both margins of the plastic film comprises a former plate having the lateral margins of one extremity tapered inward, and rotatable guide means located adjacent to the tapered extremity of the former plate and adapted to fold the two margins of the film inwardly over the tapered extremity of the former plate.
Claim 26
Dependent Claim
17 words
severing the sealed tube transversely at a mid-point of the transverse seal, thus severing consecutively produced bags.
Claim 27
Dependent Claim
17 words
severing the sealed tube transversely at a mid-point of the transverse seal, thus severing consecutively produced bags.
Claim 28
Dependent Claim
44 words
An apparatus as claimed in claim 1 wherein the means for sealing together the overlapped margins of the length of film comprises a hair pin-shaped heat-sealing element positioned to make a seal having its curved portion adjacent to the valve of the finished bag.
Claim 29
Dependent Claim
43 words
An apparatus as claimed in claim 1 wherein the means for sealing together the overlapped margins of the film includes a tongue of flexible heat-resistant, seal-inhibiting material adapted to lie between the margins to be sealed and the back wall of the bag.
Claim 30
Dependent Claim
23 words
An apparatus as claimed in claim 1 wherein the operation of the several elements is controlled and coordinated by a pneumatic-electrical control system.
Claim 31
Dependent Claim
32 words
An apparatus as claimed in claim 1 wherein the means for heat-sealing the tube transversely is adapted to concurrently seal and sever the sealed tube at the midpoint of the transverse seal.
Claim 32
Independent Claim
16 words
A method for the manufacture of valve bags in a continuous manner comprising the steps of
Claim 33
Independent Claim
16 words
A method for the manufacture of valve bags in a continuous manner comprising the steps of
References Cited (Backward Citations)
US2525139A
Cited
US3334553A
Cited
US3308722A
Cited
US3371849A
Cited
US3391615A
Cited
US3654015A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |