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US3847568A
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Vitrified abrasive element
Assignee: MWA Co
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Filing: 1972-09-18
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Granted: 1974-11-12
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Expires: 1992-09-18
Abstract
Abstract A vitrified abrasive element such as a grinding wheel made from a mixture of (1) abrasive grit composed primarily of aluminum oxide (Al2O3), (2) a ceramic bonding material which may include feldspar, frit and clay and (3) a pore-forming material comprising glass cullet such, for example, as crushed or broken soda-lime glass having a strong affinity for the abrasive grit when melted by heating. The mixture is heated to vitrify the bonding material and melt the glass cullet, causing the glass to be attracted to and coat the abrasive grit and form a bond with the abrasive grit and with the bonding material. Voids are left in the spaces previously occupied by the crushed glass, producing a porous structure.
Inventors
- 👤 J Cihon
- 👤 D Ehmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 13:18
CPC Classifications
B; B24; B24D; B24D3/00; B24D3/02; B24D3/04; B24D3/14; B24D3/18
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
61 words
A VITRIFIED ABRASIVE ELEMENT COMPRISING ABRASIVE GRIT COMPOSED PRIMARILY OF GRAINS OF ALUMINUM OXIDE (AI2O3) A POROUS CERAMIC BONDING MATERIAL, AND A GLASS WHICH COATS AND IS BONDED TO SAID ABRASIVE GRIT AND IS BONDED TO SAID CERAMIC BONDING MATERIAL, SAID GLASS HAVING NO MORE THAN TRACE AMOUNTS OF COMPOUNDS OF THE R2O3 TYPE IN WHICH R REPRESENTS ANY POSITIVE ION.
Claim 2
Dependent Claim
61 words
A VITRIFIED ABRASIVE ELEMENT COMPRISING ABRASIVE GRIT COMPOSED PRIMARILY OF GRAINS OF ALUMINUM OXIDE (AI2O3) A POROUS CERAMIC BONDING MATERIAL, AND A GLASS WHICH COATS AND IS BONDED TO SAID ABRASIVE GRIT AND IS BONDED TO SAID CERAMIC BONDING MATERIAL, SAID GLASS HAVING NO MORE THAN TRACE AMOUNTS OF COMPOUNDS OF THE R2O3 TYPE IN WHICH R REPRESENTS ANY POSITIVE ION.
Claim 3
Dependent Claim
28 words
The abrasive element defined in claim 1, wherein said glass includes a major amount of silica (SiO2) and minor amounts of sodium oxide (Na2O) and calcium oxide (CaO).
Claim 4
Dependent Claim
28 words
The abrasive element defined in claim 1 wherein said bonding material is composed of a major amount of silica (SiO2) and a minor amount of aluminum oxide (Al2O3).
Claim 5
Dependent Claim
62 words
A vitrified abrasive element comprising abrasive grit composed primarily of grains of aluminum oxide (AL2O3), soda-lime glass having no more than trace amounts of compounds of the R2O3 type in which R represents any positive ion, and a porous ceramic bonding material including feldspar, frit and clay, said soda-lime glass coating said abrasive grit and being bonded to said ceramic bonding material.
Claim 6
Dependent Claim
62 words
A vitrified abrasive element comprising abrasive grit composed primarily of grains of aluminum oxide (AL2O3), soda-lime glass having no more than trace amounts of compounds of the R2O3 type in which R represents any positive ion, and a porous ceramic bonding material including feldspar, frit and clay, said soda-lime glass coating said abrasive grit and being bonded to said ceramic bonding material.
Claim 7
Dependent Claim
22 words
The abrasive element defined in claim 4, wherein said grit is composed of about 95 percent or more of aluminum oxide (Al2O3).
Claim 8
Dependent Claim
32 words
The abrasive element defined in claim 5, wherein said soda-lime glass contains about 60 percent to about 80 percent silica (SiO2), and minor amounts of sodium oxide (Na2O) and calcium oxide (CaO).
Claim 9
Dependent Claim
26 words
The abrasive element defined in claim 6, wherein said bonding material has a major amount of silica (SiO2) and a minor amount of aluminum oxide (Al2O3).
Claim 10
Independent Claim
153 words
The method of making an abrasive element comprising providing a molded mixture of (a) abrasive grit composed primarily of grains of aluminum oxide (Al2O3), (b) unvitrified ceramic bonding material, and (c) a poreforming material comprising crushed glass having no more than trace amounts of compounds of the R2O3 type wherein R represents any positive ion and which has a strong affinity for the grains of aluminum oxide when melted by heating, and heating the molded mixture to melt the glass and cause the glass to be attracted to and coat the grains of aluminum oxide and form a bond with the abrasive grit and continuing to heat the molded mixTure to a higher temperature to vitrify the ceramic bonding material and form a bond between the glass and vitrified bonding material with voids in the latter in the spaces previously occupied by the unmelted crushed glass to form pores in the abrasive element.
Claim 11
Independent Claim
153 words
The method of making an abrasive element comprising providing a molded mixture of (a) abrasive grit composed primarily of grains of aluminum oxide (Al2O3), (b) unvitrified ceramic bonding material, and (c) a poreforming material comprising crushed glass having no more than trace amounts of compounds of the R2O3 type wherein R represents any positive ion and which has a strong affinity for the grains of aluminum oxide when melted by heating, and heating the molded mixture to melt the glass and cause the glass to be attracted to and coat the grains of aluminum oxide and form a bond with the abrasive grit and continuing to heat the molded mixTure to a higher temperature to vitrify the ceramic bonding material and form a bond between the glass and vitrified bonding material with voids in the latter in the spaces previously occupied by the unmelted crushed glass to form pores in the abrasive element.
Claim 12
Dependent Claim
31 words
The method defined in claim 8, wherein said crushed glass is soda-lime glass including a major amount of silica (SiO2) and minor amounts of sodium oxide (Na2O) and calcium oxide (CaO).
Claim 13
Dependent Claim
31 words
The method defined in claim 8, wherein said bonding material includes feldspar, frit and clay and has a major amount of silica (SiO2) and a minor amount of aluminum oxide (Al2O3).
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) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |