US3697204A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for injection molding articles of foam material
Assignee: Farrel Corp
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Filing: 1970-05-07
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Granted: 1972-10-10
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Expires: 1990-05-07
Abstract
Abstract A method of molding articles of foam material comprising melting an injection molding material and mixing the material with a blowing agent in liquid form in a plasticator at a temperature and pressure such that the temperature is below the temperature at which the liquid foaming agent converts to a gas, and forcing the mixture through an orifice which resists the flow of the material to impart heat thereto, the heat imparted being of a magnitude sufficient to raise the temperature of the mixture to at least equal that at which the liquid foaming agent converts to a gas, and delivering the mixture, containing the gas, to a mold cavity. An apparatus for molding articles of foam materials in accordance with the above method.
Inventors
- 👤 William T Kyritsis
- 👤 Robert C Simmonds Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:56
CPC Classifications
B; B29; B29C; B29C44/00; B29C44/34; B29C44/36; B29C44/38; B29C44/42; B29C44/424; B29C44/3442; B29C44/3446; Y; Y10; Y10S; Y10S264/00; Y10S264/83
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
186 words
Apparatus for injection molding foam material comprising a chamber in which thermoplastic molding material is melted, reciprocating means for mixing and melting said material in said chamber and movable in one direction as the material is melted, said reciprocating means being movable in the opposite direction to discharge the melted material from the chamber, means for introducing blowing agent in liquid form into said chamber for mixing with the melted material by the reciprocating means, means responsive to the rate and extent of movement of the reciprocating means in said one direction for causing said introducing means to introduce said blowing agent at a rate and volume proportionally related to the rate and volume of the melting of said material, means for maintaining the temperature and pressure in said chamber during said mixing such that said temperature is below the temperature at which the liquid blowing agent converts to gas, and a passage through which the mixed melted material and blowing agent is discharged, said passage having means for heating the mixture as it is discharged for causing the foaming agent to convert to a gas.
Claim 2
Dependent Claim
186 words
Apparatus for injection molding foam material comprising a chamber in which thermoplastic molding material is melted, reciprocating means for mixing and melting said material in said chamber and movable in one direction as the material is melted, said reciprocating means being movable in the opposite direction to discharge the melted material from the chamber, means for introducing blowing agent in liquid form into said chamber for mixing with the melted material by the reciprocating means, means responsive to the rate and extent of movement of the reciprocating means in said one direction for causing said introducing means to introduce said blowing agent at a rate and volume proportionally related to the rate and volume of the melting of said material, means for maintaining the temperature and pressure in said chamber during said mixing such that said temperature is below the temperature at which the liquid blowing agent converts to gas, and a passage through which the mixed melted material and blowing agent is discharged, said passage having means for heating the mixture as it is discharged for causing the foaming agent to convert to a gas.
Claim 3
Dependent Claim
98 words
Apparatus according to claim 1 and provided with a mold having an expandable cavity into which the mixture is discharged when the mold cavity is in a low volume condition and means for cooling the mold cavity to a temperature at which the gaseous blowing agent converts to liquid form so a non-foamed skin is formed on the material contacting the cavity surface, means effective after the skin is formed for expanding the mold cavity whereby the mixture of material and gaseous blowing agent away from the mold surface foams to the extent permitted by the expanding cavity.
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |