US3838962A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Molding apparatus
Assignee: Lanteris Space LLC
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Filing: 1973-05-17
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Granted: 1974-10-01
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Expires: 1993-05-17
Abstract
Abstract Molding apparatus operating on the fluid pressure forming principle comprises a pressurizable chamber having elevatable vacuum mold structure therein, including a pair of closely spaced unidirectionally presented molds. A clamping ring is positionable to hold a sheet of thermoplastic material over the upper rim of the chamber, in air-tight relation. Means is provided for heating the sheet until it sags slightly, and for introducing heated air under pressure to the chamber to billow the heat-softened sheet upwardly in an amount sufficient to achieve an initial stretch, followed by engagement of the billowed sheet by an assist-plug to urge portions thereof toward the region of adjacency of the unidirectionally presented molds, thereby forming a pair of billowed sections of lesser size. The vacuum molds are elevated into the billowed sheet portions of lesser size, and a vacuum is drawn to the opposite sides of the molds to conform the softened sheet to the latter. Heated pressurized air for billowing is supplied by a combination heater-blower device having a valving system capable of operation either to supply heated air to the chamber, or to halt the supply of air and recirculate same over the heater in anticipation of a billowing operation for an ensuing molding cycle.
Inventors
- 👤 C Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:28
CPC Classifications
B; B29; B29C; B29C51/00; B29C51/04; B29C51/26; B29C51/42; B29C51/421; B29C51/424; B29C51/10; Y; Y10; Y10S; Y10S425/00; Y10S425/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
220 words
In apparatus for forming a deep-drawn article, including mold means corresponding to the shape of the article to be formed, an assist-plug structure, means for supporting a heat-softened sheet of thermoplastic material between said mold means and said assist-plug structure, means for effecting relative movement between said mold means and said assist-plug structure to cause them to beaR against said sheet, means for producing a pressure differential across opposite surface portions of said sheet to cause it to conform to the surface of said mold means, and means for billowing said heat-softened sheet away from said mold means prior to moving said assist-plug structure and said mold means to bear against said sheet, said means for billowing comprising: blower means operable to supply air under pressure to billow said sheet of thermoplastic material; heater means disposed to heat said air moved by said blower means; and valve means selectively operable either to direct substantially full flow of air discharged by said blower means over said heater means for return to said blower means, or to direct a first portion of the air discharged by said blower means to one side of said softened sheet to billow the same and a second portion of the air discharged by said blower means over said heater means for return to said blower means.
Claim 2
Dependent Claim
220 words
In apparatus for forming a deep-drawn article, including mold means corresponding to the shape of the article to be formed, an assist-plug structure, means for supporting a heat-softened sheet of thermoplastic material between said mold means and said assist-plug structure, means for effecting relative movement between said mold means and said assist-plug structure to cause them to beaR against said sheet, means for producing a pressure differential across opposite surface portions of said sheet to cause it to conform to the surface of said mold means, and means for billowing said heat-softened sheet away from said mold means prior to moving said assist-plug structure and said mold means to bear against said sheet, said means for billowing comprising: blower means operable to supply air under pressure to billow said sheet of thermoplastic material; heater means disposed to heat said air moved by said blower means; and valve means selectively operable either to direct substantially full flow of air discharged by said blower means over said heater means for return to said blower means, or to direct a first portion of the air discharged by said blower means to one side of said softened sheet to billow the same and a second portion of the air discharged by said blower means over said heater means for return to said blower means.
Claim 3
Dependent Claim
56 words
Apparatus according to claim 1 and characterized by the inclusion of an air inlet for supplying makeup air to said blower means, said air inlet positioned to effect flow sequentially over said heater means and into said blower means, and damper means for controlling the flow rate of air caused to flow through said air inlet.
Claim 4
Dependent Claim
93 words
Apparatus according to claim 1, and characterized in that said valve means includes a damper in the stream of air discharged by said blower means, said damper being movable to a first position for directing flow of air over the heater for return to the blower means, and movable to a second position both for controlling the flow rate of air delivered by said blower means to billow said sheet of plastic and for controlling the flow rate of air discharged by said blower and recirculated over said heater thence into said blower.
Claim 5
Dependent Claim
19 words
Apparatus according to claim 3, and further characterized in that said damper is pivotally mounted for the recited movements.
Claim 6
Dependent Claim
48 words
Apparatus according to claim 3 and characterized in that said valve means further includes a gate valve downstream of said damper and selectively operable either to shut off the flow of air to said one side of said softened sheet or to accommodate full flow of such air.
Claim 7
Dependent Claim
36 words
Apparatus according to claim 1 and including thermostatic control means for establishing and maintaining the temperature of air driven by said blower means within predetermined optimum limits for the billowing of said sheets of thermoplastic material.
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) | 1977-09-30 | 1978-04-01 | 1978-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-30 | 1982-04-01 | 1982-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-30 | 1986-04-01 | 1986-10-01 | $7700.00 | Window Closed / Lapsed |