Patent US3879155A successfully refreshed from Google Patents.
US3879155A
Expired / Lapsed
US
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Closed cell foam plastic molding apparatus
Assignee: HENDRY ENGINEERING
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Filing: 1973-07-24
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Granted: 1975-04-22
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Expires: 1993-07-24
Abstract
Abstract Plastic molding machine, primarily adapted for generating and molding a closed-cell foam plastic material. The foam is generated by introducing a gas inert to the plastic material into a granular mixture of same so that the gas is thoroughly intermixed among the granular particles. The gas is then held under pressure while the granular particles are reduced to a flowable material, said pressure being sufficient to assure that the gas will not be expelled therefrom during the plasticization process. In one preferred embodiment, gas is mixed into the granular plastic in a hopper and held therein under pressure as said granular material is fed into a screw and plasticized thereby. The plastic material is then conducted at a relatively low pressure, such as that generated by the extrusion machine used for plasticizing the material, through a branched system past a check valve in each branch of said system, to an injection assembly. As each injection assembly receives a predetermined amount of plastic material, means are energized preventing more plastic material from entering thereinto but continued operation of the pressure generating device will continue filling other injection assemblies for as long as any thereof are capable of receiving such material. When all injection assemblies are filled, same are actuated simultaneously to drive the plastic material therefrom into the mold cavity. Injection assemblies may supply mold cavities in any pattern, and a single mold cavity may be associated with a given injection assembly or two or more injection assemblies may supply any one given mold cavity. Local zones, preferably subjected to rapid cooling, are provided with undercut notches connected to the sprue, runners or cavity and filled thereby with plastic. Same is cooled ahead of the cooling of the molded part and provides means for holding the mold closed. This permits removal of the mold from the machine prior to cooling of the molded part and opening of the mold which in turn permits more effective use of multiple molds with a given machine.
Inventors
- 👤 James W Hendry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:15
CPC Classifications
B; B29; B29C; B29C45/00; B29C45/17; B29C45/46; B29C44/00; B29C44/34; B29C44/3442
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
160 words
Apparatus for generating and molding a foam-plastic material comprising in combination: means defining a plasticizing chamber and a plasticizing screw contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber and means for introducing into said supply chamber a gaseous material under pressure; means for introducing into said supply chamber a granular plastic material; a thrust chamber defined by a portion of said plasticizing chamber and a portion of said plasticizing screw associated therewith, both of said chamber and screw portions projecting beyond the discharge opening of said supply chamber in a direction opposite to that of the movement of the plastic material during a plasticizing operation, and conduit means connecting said thrust chamber to the interior of said supply chamber for equalizing pressure therebetween; whereby mElting of the plastic granules while permeated by gas granules from said upper hopper into said supply chamber.
Claim 2
Dependent Claim
160 words
Apparatus for generating and molding a foam-plastic material comprising in combination: means defining a plasticizing chamber and a plasticizing screw contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber and means for introducing into said supply chamber a gaseous material under pressure; means for introducing into said supply chamber a granular plastic material; a thrust chamber defined by a portion of said plasticizing chamber and a portion of said plasticizing screw associated therewith, both of said chamber and screw portions projecting beyond the discharge opening of said supply chamber in a direction opposite to that of the movement of the plastic material during a plasticizing operation, and conduit means connecting said thrust chamber to the interior of said supply chamber for equalizing pressure therebetween; whereby mElting of the plastic granules while permeated by gas granules from said upper hopper into said supply chamber.
Claim 3
Dependent Claim
168 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber; means defining a pressure-tight supply chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for introducing into the spaces between plastic granules therein and prior to any softening of said granules a gas under a relatively high first pressure and which is the sole foam forming gas; pressure tight means defining a discharge opening from said supply chamber for supplying said granular plastic material permeated by said high pressure gas into said plasticizing chamber; plasticizing means contained in and cooperable with said plasticizing chamber for plasticizing said granular plastic material with said high pressure gas still intermixed therein; means positively closing the end of said plasticizing chamber at the end thereof opposite the direction of moving of the plastic material during a plasticizing operation for positively under pressure will arrange same around bubbles or said gas and form a plastic foam.
Claim 4
Dependent Claim
168 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber; means defining a pressure-tight supply chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for introducing into the spaces between plastic granules therein and prior to any softening of said granules a gas under a relatively high first pressure and which is the sole foam forming gas; pressure tight means defining a discharge opening from said supply chamber for supplying said granular plastic material permeated by said high pressure gas into said plasticizing chamber; plasticizing means contained in and cooperable with said plasticizing chamber for plasticizing said granular plastic material with said high pressure gas still intermixed therein; means positively closing the end of said plasticizing chamber at the end thereof opposite the direction of moving of the plastic material during a plasticizing operation for positively under pressure will arrange same around bubbles or said gas and form a plastic foam.
Claim 5
Dependent Claim
109 words
The device of claim 2 in which said means for introducing comprises an upper hopper atop said supply chamber, an opening communicating therebetween, a valve interposed in said opening for closing same and means fixed with respect to said upper hopper and actuable for opening said valve to drop a measured amount of plastic preventing the escape of high pressure gas from said end of said plasticizing chamber; and means driving said plasticizing means from the opposite end of said plasticizing chamber; whereby melting of the plastic granules while permeated by said gas under pressure will arrange the plastic around bubbles of said gas and form a plastic foam.
Claim 6
Dependent Claim
12 words
The device of claim 2 wherein said plasticizing means is a screw.
Claim 7
Dependent Claim
32 words
The device of claim 2 wherein said means for positively preventing the escape of gas from said first named end of said plasticizing chamber includes means introducing thereinto a high pressure gas.
Claim 8
Dependent Claim
179 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber and plasticizing device contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for permeating the granular mass therein with a high pressure gas prior to admission to said plasticizing chamber; a foamed plasticized material outlet in said plasticizing chamber spaced downstream along said plasticizing device from said discharge opening; backing means defined in said plasticizing chamber and by said plasticizing device upstream from said discharge opening and also connected to said high pressure gas supply means for (a) urging said plasticizing device in the downstream direction and (b) preventing escape upstream beyond said plasticizing device of gas from said discharge opening; whereby melting of the plastic granules while permeated by said high pressure gas will arrange same around bubbles of said gas and form a plastic foam.
Claim 9
Dependent Claim
179 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber and plasticizing device contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for permeating the granular mass therein with a high pressure gas prior to admission to said plasticizing chamber; a foamed plasticized material outlet in said plasticizing chamber spaced downstream along said plasticizing device from said discharge opening; backing means defined in said plasticizing chamber and by said plasticizing device upstream from said discharge opening and also connected to said high pressure gas supply means for (a) urging said plasticizing device in the downstream direction and (b) preventing escape upstream beyond said plasticizing device of gas from said discharge opening; whereby melting of the plastic granules while permeated by said high pressure gas will arrange same around bubbles of said gas and form a plastic foam.
Claim 10
Dependent Claim
179 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber and plasticizing device contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for permeating the granular mass therein with a high pressure gas prior to admission to said plasticizing chamber; a foamed plasticized material outlet in said plasticizing chamber spaced downstream along said plasticizing device from said discharge opening; backing means defined in said plasticizing chamber and by said plasticizing device upstream from said discharge opening and also connected to said high pressure gas supply means for (a) urging said plasticizing device in the downstream direction and (b) preventing escape upstream beyond said plasticizing device of gas from said discharge opening; whereby melting of the plastic granules while permeated by said high pressure gas will arrange same around bubbles of said gas and form a plastic foam.
Claim 11
Dependent Claim
179 words
Apparatus for generating a foam-plastic material comprising in combination: means defining a plasticizing chamber and plasticizing device contained therein for plasticizing granular plastic material introduced thereinto; means defining a pressure-tight supply chamber having a discharge opening in pressure-tight communication with said plasticizing chamber; means for introducing into said supply chamber a granular plastic material; high pressure gas supply means connected to said supply chamber for permeating the granular mass therein with a high pressure gas prior to admission to said plasticizing chamber; a foamed plasticized material outlet in said plasticizing chamber spaced downstream along said plasticizing device from said discharge opening; backing means defined in said plasticizing chamber and by said plasticizing device upstream from said discharge opening and also connected to said high pressure gas supply means for (a) urging said plasticizing device in the downstream direction and (b) preventing escape upstream beyond said plasticizing device of gas from said discharge opening; whereby melting of the plastic granules while permeated by said high pressure gas will arrange same around bubbles of said gas and form a plastic foam.
Claim 12
Dependent Claim
40 words
The device of claim 6 in which said backing means comprises a thrust chamber defined between the upstream ends of the plasticizing chamber and plasticizing means, and a conduit connected therefrom to said supply chamber and high pressure gas supply.
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) | 1978-04-21 | 1978-10-21 | 1979-04-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-21 | 1982-10-21 | 1983-04-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-21 | 1986-10-21 | 1987-04-22 | $7700.00 | Window Closed / Lapsed |