US4468363A — Internal mold gating method and apparatus

Claim 1

Independent Claim 181 words

A process for the internal gating of molds used to prepare a shaped article comprising a composite of aggregate filler and a curable binder, the process comprising the steps of: (a) preparing a mold having multiple surfaces enclosing its cavity, and extending gating tube means into the mold through at least one of its surfaces, the tube means extending through the mold cavity spaced from its surfaces, at least one surface of the mold having breather holes, and the tube means having walls with multiple openings therethrough which are located inside the mold cavity and distributed throughout the length of the tube means therewithin; (b) filling the cavity of the mold outside of the tube means with aggregate filler packed to close mutual proximity to leave minimum interstitial spaces therebetween; (c) pumping liquid binder into the tube means to cause it to extrude outwardly into the mold cavity through said wall openings to fill said interstitial spaces along a progressively expanding binder front while expelling air from said breather holes; and (d) curing the binder after the cavity is filled therewith.

Claim 2

Dependent Claim 181 words

A process for the internal gating of molds used to prepare a shaped article comprising a composite of aggregate filler and a curable binder, the process comprising the steps of: (a) preparing a mold having multiple surfaces enclosing its cavity, and extending gating tube means into the mold through at least one of its surfaces, the tube means extending through the mold cavity spaced from its surfaces, at least one surface of the mold having breather holes, and the tube means having walls with multiple openings therethrough which are located inside the mold cavity and distributed throughout the length of the tube means therewithin; (b) filling the cavity of the mold outside of the tube means with aggregate filler packed to close mutual proximity to leave minimum interstitial spaces therebetween; (c) pumping liquid binder into the tube means to cause it to extrude outwardly into the mold cavity through said wall openings to fill said interstitial spaces along a progressively expanding binder front while expelling air from said breather holes; and (d) curing the binder after the cavity is filled therewith.

Claim 3

Dependent Claim 39 words

The process as set forth in claim 1, wherein the article is removed from the mold after curing of the binder, and the further step of cutting off the protruding tube means flush with the surface of the article.

Claim 4

Dependent Claim 45 words

The process as set forth in claim 1, wherein said pumping of liquid binder is continued until binder has extruded from all the air breather holes, then withdrawing the tube means from the mold and packing the hole left thereby with aggregate filler and binder.

Claim 5

Dependent Claim 40 words

The process as set forth in claim 1, including extending the tube means through the mold cavity and outside the mold at plural locations on the mold surfaces; and pumping binder into the tube means simultaneously through plural mold surfaces.

Claim 6

Dependent Claim 46 words

The process as set forth in claim 1, wherein the gating tube means comprise multiple gating tubes extending through mold surfaces and through the mold cavity at spaced intervals interiorly thereof, and wherein liquid binder is pumped into the cavity through all of said gating tubes.

Claim 7

Dependent Claim 36 words

The process as set forth in claim 1, wherein the air is evacuated from the mold cavity through the breather holes while the liquid binder is pumped into the mold through the internal gating tube means.

Claim 8

Dependent Claim 78 words

The process as set forth in claim 1, including extending the tube means through the cavity and outside the mold at both ends of the tube means, inserting a snug fitting rod into the tube means from one end to virtually fill the tube means, and pumping said liquid binder into the other end of the tube means while gradually withdrawing the rod from said one end of the tube means as the mold fills with the binder.

Claim 9

Dependent Claim 28 words

The process as set forth in claim 1, wherein said mold has irregularly curved contours, the step of shaping said gating tube means to follow said curved contours.

Claim 10

Dependent Claim 25 words

The process as set forth in claim 1, wherein said aggregate filler comprises hollow spheres ranging from about 60 microns to several inches in diameter.

Claim 11

Dependent Claim 30 words

The process as set forth in claim 1, wherein said binder comprises a viscous curable syntactic foam formed of polymeric resin filled with microspheres of about 60 microns in diameter.

Claim 12

Dependent Claim 201 words

Apparatus for the internal gating of a mold used for preparing a shaped article comprising a composite of aggregate filler and a curable binder, the apparatus comprising: (a) a mold having multiple surfaces enclosing a cavity and having air breather holes through one of said surfaces and having binder-filling port means extending through at least one of said surfaces; (b) gating tube means having a central bore communicating with said port means passing through at least one of said surfaces, the gating tube extending through the mold cavity in spaced relationship to its surfaces, the walls of the tube means inside the cavity having multiple opening therethrough communicating from the bore of the tube means into the cavity, the openings being distributed along the length of the tube walls located in the cavity, the space within the cavity of the mold and outside of the tube means receiving said aggregate filler; and (c) pump means connected through the port means to the tube means and operative to pump binder into the tube means from outside the mold, and through the openings to fill the cavity and occupy the interstitial spaces between the filler aggregate while expelling air from the breather holes.

Claim 13

Dependent Claim 201 words

Apparatus for the internal gating of a mold used for preparing a shaped article comprising a composite of aggregate filler and a curable binder, the apparatus comprising: (a) a mold having multiple surfaces enclosing a cavity and having air breather holes through one of said surfaces and having binder-filling port means extending through at least one of said surfaces; (b) gating tube means having a central bore communicating with said port means passing through at least one of said surfaces, the gating tube extending through the mold cavity in spaced relationship to its surfaces, the walls of the tube means inside the cavity having multiple opening therethrough communicating from the bore of the tube means into the cavity, the openings being distributed along the length of the tube walls located in the cavity, the space within the cavity of the mold and outside of the tube means receiving said aggregate filler; and (c) pump means connected through the port means to the tube means and operative to pump binder into the tube means from outside the mold, and through the openings to fill the cavity and occupy the interstitial spaces between the filler aggregate while expelling air from the breather holes.

Claim 14

Dependent Claim 28 words

Apparatus as set forth in claim 11, wherein said openings in the walls of the tube means are smaller in diameter than the diameter of said filler aggregate.

Claim 15

Dependent Claim 74 words

Apparatus as set forth in claim 11, wherein some of said filler aggregate is smaller in diameter than said openings in said tube means, and a rod which is a snug fit in the bore of the tube means being inserted therein to keep the aggregate from entering the tube means, the rod being withdrawn from one end of the tube means as binder is pumped into the other end of the tube means.

Claim 16

Dependent Claim 36 words

Apparatus as set forth in claim 11, wherein a tube means has plural ends extending outside the mold at plural port means; and manifold means connecting said tube means ends together and to said pump means.

Claim 17

Dependent Claim 41 words

Apparatus as set forth in claim 11, wherein said gating tube means comprise multiple gating tubes extending from the mold surfaces through the cavity in mutually spaced relationship interiorly thereof, and manifold means connecting said gate tubes to said pump means.

Claim 18

Dependent Claim 35 words

Apparatus as set forth in claim 11, further comprising vacuum pump means connected to said cavity through said air breather holes, and operative to evacuate the mold while said pumping means is pumping binder thereinto.

Claim 19

Dependent Claim 27 words

Apparatus as set forth in claim 11, wherein said mold surfaces having curved contours, and wherein said gating tube means comprise tubing curved to follow said contours.

Claim 20

Dependent Claim 107 words

Apparatus as set forth in claim 11, wherein said tube means comprises a gating tube extending through the mold cavity and outside the mold at both of its ends, a snug fitting rod inserted in the gating tube from one end and virtually filling the tube, the pumping means being connected to the other end of the tube, and means for biasing the rod to yieldably resist its expulsion from said one end of the tube, whereby the rod is expelled gradually to cause the filling of the tube with said binder to progress at a rate proportional to the rate at which the cavity is filled.

Claim 21

Dependent Claim 36 words

Apparatus as set forth in claim 11, wherein said aggregate filler comprises sealed hollow macrospheres, and said binder comprises syntactic foam made of curable resin filled with hollow microspheres up to about 60 microns in diameter.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-08-28	1988-02-27	1988-08-28	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-08-28	1992-02-27	1992-08-28	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-08-28	1996-02-27	1996-08-28	$7700.00	Window Closed / Lapsed

Internal mold gating method and apparatus

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