Patent US3910798A successfully refreshed from Google Patents.
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 23:33
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)
US2908952A
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 |