Patent US3675708A successfully refreshed from Google Patents.
US3675708A
Expired / Lapsed
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Method of making accurate cores
Assignee: Northrop Grumman Space and Mission Systems Corp
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Filing: 1970-12-16
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Granted: 1972-07-11
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Expires: 1990-12-16
Abstract
Abstract Method for making shell-type cores which involves joining together a plurality of core patterns which when joined provide a hollow composite pattern, each of the patterns having ribs extending therealong. The composite pattern is invested in a ceramic mold making material to form outer and inner ceramic shells about the composite pattern. A portion of the outer shell is then removed to expose at least a portion of the ribs. Upon melting out of the pattern, the discontinuity created by the presence of the ribs causes the outer shell to come apart and leaves the inner shell intact. The inner shell which is in the configuration of the desired core is then fired to provide a rigid shell-type core.
Inventors
- 👤 William S Blazek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:40
CPC Classifications
B; B22; B22C; B22C7/00; B22C7/02; B22C7/023; B22C7/026; B22C9/00; B22C9/02; B22C9/04; B22C9/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
102 words
The method of making a shell-type core which comprises joining together a plurality of core patterns which when joined provide a hollow composite pattern, said patterns each having ribs extending from the peripheries thereof, investing the composite pattern in a ceramic mold making material to form outer and inner ceramic shells about said composite pattern, removing a portion of the outer shell to thereby expose at least a portion of said ribs, melting out the pattern to thereby cause the outer shell to come apart and leaving the inner shell intact, and firing the inner shell to provide a rigid shell-type core.
Claim 2
Independent Claim
102 words
The method of making a shell-type core which comprises joining together a plurality of core patterns which when joined provide a hollow composite pattern, said patterns each having ribs extending from the peripheries thereof, investing the composite pattern in a ceramic mold making material to form outer and inner ceramic shells about said composite pattern, removing a portion of the outer shell to thereby expose at least a portion of said ribs, melting out the pattern to thereby cause the outer shell to come apart and leaving the inner shell intact, and firing the inner shell to provide a rigid shell-type core.
Claim 3
Dependent Claim
14 words
The method of claim 1 in which said ribs extend longitudinally of said patterns.
Claim 4
Dependent Claim
23 words
The method of claim 1 in which said ribs are positioned to provide a continuous rib extending the length of the composite pattern.
Claim 5
Dependent Claim
13 words
The method of claim 1 in which said pattern is composed of wax.
Claim 6
Dependent Claim
13 words
The method of claim 1 in which said pattern is composed of polystyrene.
Claim 7
Dependent Claim
15 words
The method of claim 1 in which said core patterns are joined together by heat.
References Cited (Backward Citations)
US3424227A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |