Patent US3945429A successfully refreshed from Google Patents.
US3945429A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Decomposable passage-way forming core
Assignee: Saab AB
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Filing: 1974-03-05
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Granted: 1976-03-23
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Expires: 1994-03-05
Abstract
Abstract The present invention relates to a method for forming a canal when moulding a metal block, said canal being defined by a core inserted into the mould. The method involves using a core comprising a tube of powdered or granulated refractory material held together by an organic binding agent, and a rod located within the tube, coating the core with a blacking agent prior to moulding, carrying out the moulding operation and simultaneously combusting the binding agent and leading off gases through the core, and finally removing the rod and clearing away the remnants of the tube in the canal formed. The invention also provides a core suitable for use in said method.
Inventors
- 👤 Hans Sigvard Wahlqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:31
CPC Classifications
B; B22; B22C; B22C9/00; B22C9/10; B22C9/106
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
114 words
A decomposable, passage-way forming core for use in a mold during the molding of molten material comprising: a separate preformed tube of powdered or granulated refractory material held together by an organic binding agent which is thermally decomposable at a temperature below the melting point of the molten material being molded and which gives off little gas when thermally decomposed; and an elongated reinforcing member disposed within the bore of said tube in contact therewith so as to support said tube during the molding operation and be removable from said tube upon completion of the molding operation, said elongated reinforcing member forming with the bore of the tube at least one longitudinally extending vent.
Claim 2
Dependent Claim
114 words
A decomposable, passage-way forming core for use in a mold during the molding of molten material comprising: a separate preformed tube of powdered or granulated refractory material held together by an organic binding agent which is thermally decomposable at a temperature below the melting point of the molten material being molded and which gives off little gas when thermally decomposed; and an elongated reinforcing member disposed within the bore of said tube in contact therewith so as to support said tube during the molding operation and be removable from said tube upon completion of the molding operation, said elongated reinforcing member forming with the bore of the tube at least one longitudinally extending vent.
Claim 3
Dependent Claim
23 words
A core as in claim 1 wherein said elongated member is a rod of lesser transverse cross-section than the bore of said tube.
Claim 4
Dependent Claim
17 words
A core as in claim 1 wherein the surface of said elongated member is grooved or beveled.
Claim 5
Dependent Claim
13 words
A core as in claim 1 wherein the refractory material is ceramic material.
Claim 6
Dependent Claim
22 words
A core as in claim 1 wherein the refractory material is selected from the group consisting of crushed glass and silica sand.
Claim 7
Dependent Claim
12 words
A core as in claim 1 wherein the binding agent is cellulose.
Claim 8
Dependent Claim
80 words
A core as in claim 1 for use in molding cast iron or an alloy thereof wherein the temperature at which the binding agent is thermally decomposed is at least 100°C lower than the melting point of the cast iron, the binding agent being capable of being thermally decomposed at a temperature below 600°C and comprising cellulose and the proportion of binding agent being less than 6 percent of the total weight of the refractory material and the binding agent.
Claim 9
Dependent Claim
32 words
A core as in claim 1 including a blackening agent coated onto the tube, the blackening agent resisting temperatures at least equal to the melting point of the material to be molded.
Claim 10
Dependent Claim
21 words
A core as in claim 8 wherein the blackening agent is selected from the group consisting of graphite and silica flour.
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) | 1979-03-23 | 1979-09-22 | 1980-03-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-23 | 1983-09-22 | 1984-03-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-23 | 1987-09-22 | 1988-03-23 | $7700.00 | Window Closed / Lapsed |