US3910798A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Moulding process
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1972-10-10
•
Granted: 1975-10-07
•
Expires: 1992-10-10
Abstract
Abstract A process for the manufacture of an investment casting mold which comprises coating an expendable pattern in a thixotropic dip slurry, drying the coating, removing the pattern and firing the mold.
Inventors
- 👤 Michael John Shires
- 👤 John Edwin White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:12
CPC Classifications
B; B22; B22C; B22C1/00; B22C1/16; B22C1/18; B22C1/183; B22C1/165
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
84 words
IN A PROCESS FOR THE MANUFACTURE OF AN INVESTMENT CASTING MOULD WHICH COMPRISES THE STEPS OF COATING AN EXPENDABLE PATTERN BY IMMERSION IN A FLUID MIXTURE COMPRISING A REFACTORY MATERIAL, A BINDER, AND A LIQUID DISPERANT, DRYING THE COATING REMOVING THE PATTERN AND FIRING THE MOLD, THE IMPROVEMENT COMPRISING ADDING TO SAID MIXTURE A THICKENING AGENT IN AN AMOUNT SUFFICIENT TO RENDER THE MIXTURE THIXOTROPIC, AND REQUIRING A SHEAR STRESS OF AT LEAST 100 DYENES/CM2 TO BREAK ITS STRUCTURE FROM A SOLID TO LIQUID.
Claim 2
Dependent Claim
84 words
IN A PROCESS FOR THE MANUFACTURE OF AN INVESTMENT CASTING MOULD WHICH COMPRISES THE STEPS OF COATING AN EXPENDABLE PATTERN BY IMMERSION IN A FLUID MIXTURE COMPRISING A REFACTORY MATERIAL, A BINDER, AND A LIQUID DISPERANT, DRYING THE COATING REMOVING THE PATTERN AND FIRING THE MOLD, THE IMPROVEMENT COMPRISING ADDING TO SAID MIXTURE A THICKENING AGENT IN AN AMOUNT SUFFICIENT TO RENDER THE MIXTURE THIXOTROPIC, AND REQUIRING A SHEAR STRESS OF AT LEAST 100 DYENES/CM2 TO BREAK ITS STRUCTURE FROM A SOLID TO LIQUID.
Claim 3
Dependent Claim
29 words
A process according to claim 1 in which the thixotropic mixture requires a shear stress of at least 3000 dynes/cm2 to break its structure from a solid to liquid.
Claim 4
Dependent Claim
43 words
A process according to any of claim 1, in which the thixotropic mixture is subjected to shear conditions at least in the region of the pattern for a least a portion of the time for which the pattern is immersed in the mixture.
Claim 5
Dependent Claim
31 words
A process according to claim 3 in which the mixture is subjected to shear such that its viscosity in the immediate vicinity of the pattern is within the range 10-25 poises.
Claim 6
Dependent Claim
22 words
A process as claimed in claim 1 wherein the pattern is coated with a primer coating before application of the thixotropic mixture.
Claim 7
Dependent Claim
17 words
A process as claimed in claim 1 wherein a single coating of the thixotropic mixture is applied.
Claim 8
Dependent Claim
18 words
A process as claimed in claim 1 wherein the thixotropic mixture contains a treated clay as thickening agent.
Claim 9
Dependent Claim
17 words
A process as claimed in claim 7 wherein the treated clay is a modified magnesium silicate clay.
Claim 10
Dependent Claim
21 words
A process as claimed in claim 1 wherein the thixotropic mixture contains 0.1 to 10% by weight of the thickening agent.
Claim 11
Dependent Claim
13 words
An investment casting mould produced by the process as claimed in claim 1.
References Cited (Backward Citations)
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Cited
US3005244A
Cited
US3243397A
Cited
US3241200A
Cited
US3421909A
Cited
US3519444A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |