Patent US3673296A successfully refreshed from Google Patents.
US3673296A
Expired / Lapsed
US
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Method for electrostatically holding particles along a mold surface
Assignee: Continental Can Co Inc
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Filing: 1969-05-09
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Granted: 1972-06-27
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Expires: 1989-05-09
Abstract
Abstract Particles of plastic material are attracted to a mold surface by impressing an electrostatic charge on the particles subsequent to their deposit, minimizing disturbance of the deposition stream and sticking of powder in the deposition apparatus. A roll deposition unit and corona bar are employed in association with a rotating mold to form a cylindrical member from powdered plastic material. The unit deposits powder in a strip zone lengthwise of the mold. The corona bar is positioned externally of the roll case, parallel to and coextensive with the roll and closest to the cylindrical mold wall in a plane outside the stream of powder flowing from the roll to the mold wall. When the bar is charged and the mold is grounded, the resultant discharge is largely concentrated outside the stream, minimizing electrostatic effect on particles in the stream.
Inventors
- 👤 Charles A Timko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:15
CPC Classifications
B; B29; B29C; B29C41/00; B29C41/02; B29C41/08; B05; B05C; B05C19/00; B05C19/04; B05D; B05D1/00; B05D1/30; B05D3/00; B05D3/14; B05D3/141; B05D3/142; B05D7/00; B05D7/22; B05D7/222; B05D1/002; B05D1/007; B05D2401/00; B05D2401/30; B05D2401/32
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
111 words
In a method of moldIng an article from comminuted particles of an electrically non-conductive material upon a mold surface to which said particles are fixed in place during said molding, including the steps of depositing a layer of said comminuted particles along successive portions of said mold surface, and fusing said particles to each other for forming a blanket of said material upon said mold surface; the improvement comprising: imposing an electrostatic charge to said layer of particles only subsequent to performing said step of depositing said particles for causing said particles to be electrostatically fixed in place relative to said mold surface until said particles have assimilated in said blanket.
Claim 2
Dependent Claim
111 words
In a method of moldIng an article from comminuted particles of an electrically non-conductive material upon a mold surface to which said particles are fixed in place during said molding, including the steps of depositing a layer of said comminuted particles along successive portions of said mold surface, and fusing said particles to each other for forming a blanket of said material upon said mold surface; the improvement comprising: imposing an electrostatic charge to said layer of particles only subsequent to performing said step of depositing said particles for causing said particles to be electrostatically fixed in place relative to said mold surface until said particles have assimilated in said blanket.
Claim 3
Dependent Claim
44 words
A method as defined in claim 1 wherein said particles are assimilated into a blanket by the step of heating said mold to a temperature at least as high as the melting temperature of said particles prior to the step of depositing said particles.
Claim 4
Dependent Claim
58 words
A method as defined in claim 1 wherein the step of depositing said particles is accomplished with the aid of gravity, and includes the step of rotating said mold about said particles which are being deposited for carrying deposited particles past a source of electrostatic charges located remote from the point at which said particles are being deposited.
Claim 5
Dependent Claim
153 words
In a method of forming a hollow cylindrical plastic member, including providing a mold having a cylindrical cavity, heating said mold, rotating said mold about the axis of said cavity, and directing a stream of comminuted plastic material against the wall of said cavity in a deposition zone so as to effect assimilation of said material along said wall, the improvement comprising positioning a corona bar in said cavity with said bar extending lengthwise of said wall coextensively with said zone and said bar closest to said wall along a line thereof outside said zone, and creating an electrostatic discharge between said bar and said wall so as to concentrate charging effect of said discharge on said material largely along said line, thereby charging particles of said material carried on said wall upon crossing said line and effecting attraction of said particles to said wall free of significant electrostatic effect in said zone.
Claim 6
Dependent Claim
153 words
In a method of forming a hollow cylindrical plastic member, including providing a mold having a cylindrical cavity, heating said mold, rotating said mold about the axis of said cavity, and directing a stream of comminuted plastic material against the wall of said cavity in a deposition zone so as to effect assimilation of said material along said wall, the improvement comprising positioning a corona bar in said cavity with said bar extending lengthwise of said wall coextensively with said zone and said bar closest to said wall along a line thereof outside said zone, and creating an electrostatic discharge between said bar and said wall so as to concentrate charging effect of said discharge on said material largely along said line, thereby charging particles of said material carried on said wall upon crossing said line and effecting attraction of said particles to said wall free of significant electrostatic effect in said zone.
Claim 7
Dependent Claim
57 words
The method as defined in claim 4, said bar being elongated parallel to said axis and outside said stream and positioned closest to said wall in a plane common to a line of said wall immediately beyond said zone in the direction of mold rotation, including grounding said mold, and impressing an electrostatic charge on said bar.
References Cited (Backward Citations)
US3301925A
Cited
US3491170A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |