US3873659A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming articles from plastic sheet material
Assignee: Lanteris Space LLC
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Filing: 1973-08-01
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Granted: 1975-03-25
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Expires: 1993-08-01
Abstract
Abstract A vacuum-forming method for making a pair of adjacent compartment liners from a single sheet of thermoplastic material. A sheet of thermoplastic material is disposed to extend over the molds and is heated to a pliable, softened state while the molds are held in pivoted positions, in which the confronting surfaces are substantially spaced from one another, and while the table structure is held in upwardly tilted position. The pliable sheet of thermoplastic material is then caused to billow away from the pivoted and tilted molds, whereupon mold assist-plugs and the molds are then moved, relatively, toward one another, to urge the sheet to generally close conformity with the molds. While the sheet of thermoplastic material is still pliable, the frame structure is pivoted to cause confronting adjacent wall portions of the mold to move toward one another and assume a closely spaced relation, while the table structure is moved from its tilted position to a substantially horizontal position. Air entrapped between the pliable sheet and the walls of the molds is then evacuated through a number of small ports or vents in the walls, thereby forming the desired liners over the molds. The liners are then cooled and stripped as a unit from the molds.
Inventors
- 👤 Robert J Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:17
CPC Classifications
B; B29; B29C; B29C51/00
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
281 words
In a method of forming an article, comprising a pair of adjacent walled structures having unidirectionally presented openings, from a sheet of thermoplastic material, utilizing a pair of unidirectionally presented molds shaped in correspondence to the structures to be formed and so associated as to be movable on table structure between one position in which confronting walls thereof are closely spaced in accordance with the spacing of the structures to be formed and another position in which said confronting walls are spaced apart a substantially greater distance than in said one position, the steps which comprise: suspending a unitary, softened sheet of thermoplastic material over said molds, restraining at least one edge of said sheet, tilting said table structure about an axis extending transversely of the direction of relative movement of said molds and parallel to and spaced from said restrained edge therEby to increase the spacing between said restrained edge of said sheet and a confronting portion of one of said molds as said molds are moved into contact with said sheet; moving said molds to the mentioned other position in which the confronting walls of said molds are substantially spaced apart; causing said softened sheet to billow away from said molds; relatively translating said molds and said billowed sheet toward one another sufficient to engage the tilted and spaced apart molds therewith; moving said molds to horizontal non-tilted position and to said one position in which they are closely spaced, and engaging said sheet with an assist-plug to stretch the softened sheet over said molds; and utilizing differential fluid pressure to cause said softened sheet to conform to the surface of said molds in said one, closely spaced position.
Claim 2
Dependent Claim
281 words
In a method of forming an article, comprising a pair of adjacent walled structures having unidirectionally presented openings, from a sheet of thermoplastic material, utilizing a pair of unidirectionally presented molds shaped in correspondence to the structures to be formed and so associated as to be movable on table structure between one position in which confronting walls thereof are closely spaced in accordance with the spacing of the structures to be formed and another position in which said confronting walls are spaced apart a substantially greater distance than in said one position, the steps which comprise: suspending a unitary, softened sheet of thermoplastic material over said molds, restraining at least one edge of said sheet, tilting said table structure about an axis extending transversely of the direction of relative movement of said molds and parallel to and spaced from said restrained edge therEby to increase the spacing between said restrained edge of said sheet and a confronting portion of one of said molds as said molds are moved into contact with said sheet; moving said molds to the mentioned other position in which the confronting walls of said molds are substantially spaced apart; causing said softened sheet to billow away from said molds; relatively translating said molds and said billowed sheet toward one another sufficient to engage the tilted and spaced apart molds therewith; moving said molds to horizontal non-tilted position and to said one position in which they are closely spaced, and engaging said sheet with an assist-plug to stretch the softened sheet over said molds; and utilizing differential fluid pressure to cause said softened sheet to conform to the surface of said molds in said one, closely spaced position.
Claim 3
Dependent Claim
39 words
The method according to claim 1, and characterized in that said molds are moved pivotally between recited positions thereof, and further in that the axis of pivotation is substantially parallel to the axis of tilting of said table structure.
Claim 4
Dependent Claim
29 words
The method according to claim 1, and further characterized in that said assist-plug engages said billowed sheet prior to engagement of the sheet by said tilted and spaced-apart molds.
Claim 5
Dependent Claim
76 words
the method according to claim 1, and characterized in that the projected area on the billowed sheet of the one of the recited, tilted and spaced-apart molds which is closer to said sheet than the other of said molds after said table structure is tilted is less than the projected area on said billowed sheet of the other one of said molds, the depth of draw onto each said molds being substantially in the same amount.
References Cited (Backward Citations)
US3781394A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |