US3815535A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and process for the making and coating of hollow bodies
Assignee: SCHWAAB W LACKFAB KG INH GEB B
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Filing: 1972-12-14
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Granted: 1974-06-11
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Expires: 1992-12-14
Abstract
Abstract Metallic hollow bodies such as cans or other containers, particularly non-ferrous cans such as aluminum, are electromagnetically suspended and coated on their outside and inside surfaces simultaneously by applying, in an electrostatic field wherein the metallic hollow body is grounded, a resinous powder coating material, and whereafter the hollow body is subjected to a heat treatment, to result in formation of a continuous resin film coating on the surfaces of the hollow body. In the case of non-ferrous (e.g., aluminum) cans, cans susceptible to electromagnetic suspension are manufactured from aluminum (or other non-ferrous) sheet by adhering iron mesh to the cup-bottom during the cup-forming step.
Inventors
- 👤 G Becker
- 👤 K Kleindrettle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:57
CPC Classifications
B; B21; B21D; B21D51/00; B21D51/16; B21D51/26
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
202 words
Process for producing imprinted aluminum cans from aluminum sheet, which process comprises: a. forming a cup from the aluminum sheet while simultaneously adhering a strip of iron webbing to cover at least part of the bottom portion of the cup; b. subjecting the thus formed cup, having said iron webbing adhered or partly imbedded in its bottom portion, to a washing step to result in substantial defatting of the cup; c. suspending the washed cup electromagnetically by means of the iron webbing adhered thereto; d. subjecting the thus-suspended cup to an electrostatic field wherein the suspended can acts as the grounding element; e. positioning nozzles capable of delivering particulated resinous coating powder in spray form to the outside and inside surfaces of the suspended cup in said electrostatic field; f. subjectiNg the sprayed cup having resin coating particles adhering thereto to a first heat treatment to form a continuous film of molten resin particles covering all sprayed surfaces of the can g. while the thus formed film is still incompletely dried, imprinting the film covered can; and h. returning said imprinted cup to a second heat treatment to firmly bake on the imprinted matter and to permanently dry the said film coating.
Claim 2
Dependent Claim
202 words
Process for producing imprinted aluminum cans from aluminum sheet, which process comprises: a. forming a cup from the aluminum sheet while simultaneously adhering a strip of iron webbing to cover at least part of the bottom portion of the cup; b. subjecting the thus formed cup, having said iron webbing adhered or partly imbedded in its bottom portion, to a washing step to result in substantial defatting of the cup; c. suspending the washed cup electromagnetically by means of the iron webbing adhered thereto; d. subjecting the thus-suspended cup to an electrostatic field wherein the suspended can acts as the grounding element; e. positioning nozzles capable of delivering particulated resinous coating powder in spray form to the outside and inside surfaces of the suspended cup in said electrostatic field; f. subjectiNg the sprayed cup having resin coating particles adhering thereto to a first heat treatment to form a continuous film of molten resin particles covering all sprayed surfaces of the can g. while the thus formed film is still incompletely dried, imprinting the film covered can; and h. returning said imprinted cup to a second heat treatment to firmly bake on the imprinted matter and to permanently dry the said film coating.
Claim 3
Dependent Claim
39 words
Process as claimed in claim 1 wherein two cup-forming lines supply a single electrostatic coating zone and there is at least one offset printing line to receive the film-covered can from said coating zone after said first heating step.
Claim 4
Dependent Claim
37 words
Process as claimed in claim 1 wherein subsequent to said first heating step (f) said can is mechanically deformed at the base thereof to form a concave bottom, resulting in falling out of said iron webbing strip.
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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |