US3619240A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Mechanically strengthening articles made of vitreous or ceramic materials
Assignee: AGC Glass Europe SA
•
Filing: 1968-04-18
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Granted: 1971-11-09
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Expires: 1988-04-18
Abstract
Abstract Processes for increasing the mechanical strength of articles made of glass, vitrocrystalline materials or ceramic materials by coating at least certain surface portions of a base layer with a coating of glass substance having a lower softening temperature and a lower coefficient of thermal expansion than the material of the base layer, the coating material being brought to a temperature which is sufficiently high to place it in at least a softened state and the resulting unit then being cooled to produce compressive stresses in the layer of coating material. Articles composed of a base layer and a coating layer having a lower coefficient of thermal expansion and a lower softening temperature than the base layer, the coating layer having been placed in a softened condition either before or after having been applied to the base layer.
Inventors
- 👤 Francois Toussaint
- 👤 Maurice Boffe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:08
CPC Classifications
C; C04; C04B; C04B41/00; C04B41/45; C04B41/50; C04B41/5022; C03; C03C; C03C17/00; C03C17/02; C03C21/00
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
25 words
A process as defined in claim 1 further comprising the step of applying the glass coating to the entire edge surface of the base layer.
Claim 2
Dependent Claim
54 words
A process as defined in claim 1 wherein the base layer is in the form of a sheet and said step of applying is carried out so as to cover the portion of each large surface of the sheet which is adjacent at least one part of the edge surface with the glass coating.
Claim 3
Dependent Claim
29 words
A process as defined in claim 3 wherein the at least one part of the edge of the surface of the sheet is also covered with the glass coating.
Claim 4
Dependent Claim
17 words
A process as defined in claim 1 wherein the median surface of the base layer is flat.
Claim 5
Dependent Claim
17 words
A process as defined in claim 1 wherein the median surface of the base layer is curved.
Claim 6
Dependent Claim
54 words
A process as defined in claim 6 wherein the base layer constitutes the wall of a piece of hollowware having a rim, and said step of applying is carried out so as to provide a glass coating on the portions of the inside and outside surfaces of this wall which are adjacent the rim.
Claim 7
Dependent Claim
20 words
A process as defined in claim 7 wherein the rim of the article is also covered with the glass coating.
Claim 8
Dependent Claim
26 words
A process as defined in claim 1 wherein said step of applying a glass coating is carried out by applying molten glass to the base layer.
Claim 9
Dependent Claim
51 words
A process as defined in claim 1 wherein said step of applying a glass coating is carried out by applying, in solid form, a material from which the glass coating is to be formed to the base layer, and subsequently placing the material in at least a softened state in situ.
Claim 10
Dependent Claim
24 words
A process as defined in claim 10 wherein the material from which the coating is to be formed is constituted by the coating glass.
Claim 11
Dependent Claim
42 words
A process as defined in claim 10 wherein the material from which the glass coating is to be formed is constituted by a glass-forming substance and said step of applying a glass coating further includes forming the coating glass from such substance.
Claim 12
Dependent Claim
37 words
A process as defined in claim 10 wherein the material from which the glass coating is to be formed is in powder form and is placed in suspension in a liquid for application to the base layer.
Claim 13
Dependent Claim
27 words
A process as defined in claim 13 wherein the liquid suspension is applied to the base layer by dipping the layer in a bath of such liquid.
Claim 14
Dependent Claim
18 words
A process as defined in claim 13 wherein the suspension is applied to the base layer by spraying.
Claim 15
Dependent Claim
33 words
A process as defined in claim 10 wherein the material from which the coating is formed is in powder form and is mixed into a pasty medium for deposition on the base layer.
Claim 16
Dependent Claim
48 words
A process as defined in claim 1 wherein said steps of applying a glass coating and heating the coating to a temperature which places it in a softened state are carried out by melting the glass coating material and then applying the molten material to the base layer.
Claim 17
Dependent Claim
22 words
A process as defined in claim 17 wherein the molten material is applied by dipping the base layer in a bath thereof.
Claim 18
Dependent Claim
19 words
A process as defined in claim 17 wherein the molten material is applied by spraying onto the base layer.
Claim 19
Dependent Claim
36 words
A process as defined in claim 1 wherein the step of applying a glass coating is carried out by vacuum deposition onto the base layer of a material from which the coating is to be formed.
Claim 20
Dependent Claim
47 words
A process as defined in claim 1 wherein said step of heating the coating to a temperature which places it in a softened state is carried out so as to bring the temperature of the base layer to a value which is close to its softening point.
Claim 21
Dependent Claim
58 words
A process as defined in claim 1 wherein the glass coating originally contains sodium or lithium ions and said step of chemically tempering is carried out so as to introduce potassium ions into the coating in exchange for the sodium or lithium ions, the tempering being carried out at a temperature below the annealing temperature of the coating.
Claim 22
Dependent Claim
25 words
A process as defined in claim 22 wherein said step of cHemically tempering is carried out by immersing the resulting article in molten potassium nitrate.
Claim 23
Dependent Claim
41 words
A process as defined in claim 1 wherein said step of chemically tempering is carried out at a temperature above the strain point of the coating and involves the substitution of lithium ions for sodium ions originally present in the coating.
Claim 24
Dependent Claim
53 words
A process as defined in claim 1 wherein the coating is of a material which is more easily chemically tempered than is the material of the base layer and said step of subjecting the article to a diffusion operation serves to chemically temper the coating to a greater degree than the base layer.
References Cited (Backward Citations)
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Cited
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Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |