US3810068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Impedance element with magnesium reaction terminal contact and method
Assignee: Corning Glass Works
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Filing: 1973-05-07
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Granted: 1974-05-07
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Expires: 1993-05-07
Abstract
Abstract An electrical impedance device is hermetically sealed within an encapsulating sleeve while external leads are simultaneously electrically connected thereto. The impedance element is disposed in an encapsulating sleeve which extends beyond the ends thereof. Magnesium is disposed within the ends of the sleeve, and one end of an external lead is placed in each end of the sleeve adjacent to the end of the impedance element. A bead of fusible material is disposed about the lead and is positioned adjacent to the end of the sleeve. Heat is applied to that portion of the assembly so formed including the bead and the end portion of the sleeve to cause the bead to form a hermetic seal with the lead and the sleeve and to cause the magnesium to vaporize and form a conductive cermet layer which forms an electrical connection between the lead and the electrical terminal of the impedance element. The magnesium also reacts with sleeve and bead to form a magnesium reaction product.
Inventors
- 👤 Luca R De
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 00:05
CPC Classifications
H; H01; H01C; H01C1/00; H01C1/14; H01C1/144; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49087; Y10T29/49098
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
169 words
A method of forming an encapsulated impedance device comprising the steps of providing an impedance element having at least one electrical terminal at an end thereof, providing a sleeve of fusible encapsulating material having at least one open end, disposing said sleeve about said impedance element so that said open end extends beyond and provides access to said terminal, disposing magnesium in said open end of said sleeve, placing an end of an external lead into said open end of said sleeve, disposing a fusible element about said lead intermediate the ends thereof, said fusible element having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to that portion of the assembly so formed including said fusible element and the adjacent poRtion of said sleeve to cause said fusible element to form a hermetic seal with said lead and said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer extending between said electrical terminal and said lead.
Claim 2
Independent Claim
169 words
A method of forming an encapsulated impedance device comprising the steps of providing an impedance element having at least one electrical terminal at an end thereof, providing a sleeve of fusible encapsulating material having at least one open end, disposing said sleeve about said impedance element so that said open end extends beyond and provides access to said terminal, disposing magnesium in said open end of said sleeve, placing an end of an external lead into said open end of said sleeve, disposing a fusible element about said lead intermediate the ends thereof, said fusible element having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to that portion of the assembly so formed including said fusible element and the adjacent poRtion of said sleeve to cause said fusible element to form a hermetic seal with said lead and said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer extending between said electrical terminal and said lead.
Claim 3
Dependent Claim
28 words
A method in accordance with claim 1 further comprising the step of urging said end of said lead toward said impedance element during the step of applying heat.
Claim 4
Dependent Claim
59 words
A method in accordance with claim 1 wherein said fusible element is spaced from the end of said impedance element so that the step of applying heat results in the formation of a cavity between said impedance element, sleeve and fusible element, and further causes said magnesium to react with oxygen in said cavity to reduce the pressure therein.
Claim 5
Independent Claim
187 words
A method of forming an encapsulated impedance device comprising the steps of providing an impedance element having electrical terminals at opposed ends thereof, disposing a sleeve of encapsulating material about said impedance element, the first and second open ends of said sleeve extending beyond the ends of said impedance element, disposing magnesium in the first and second ends of said sleeve, inserting a first end of a first external lead into said first open end of said sleeve, inserting a first end of a second external lead into said second end of said sleeve, disposing a fusible element about each of said leads intermediate the ends thereof, said fusible elements having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to those portions of the assembly so formed including said fusible elements and the adjacent ends of said sleeve to cause said fusible elements to form hermetic seals with their corresponding leads and with the corresponding ends of said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer between said electrical terminals and said leads.
Claim 6
Independent Claim
187 words
A method of forming an encapsulated impedance device comprising the steps of providing an impedance element having electrical terminals at opposed ends thereof, disposing a sleeve of encapsulating material about said impedance element, the first and second open ends of said sleeve extending beyond the ends of said impedance element, disposing magnesium in the first and second ends of said sleeve, inserting a first end of a first external lead into said first open end of said sleeve, inserting a first end of a second external lead into said second end of said sleeve, disposing a fusible element about each of said leads intermediate the ends thereof, said fusible elements having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to those portions of the assembly so formed including said fusible elements and the adjacent ends of said sleeve to cause said fusible elements to form hermetic seals with their corresponding leads and with the corresponding ends of said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer between said electrical terminals and said leads.
Claim 7
Dependent Claim
72 words
A method in accordance with claim 4 wherein said fusible elements are spaced from the ends of said impedance element so that the step of applying heat results in the formation of a cavity at each end of said impedance element between said impedance element, the adjacent end of said sleeve and said fusible element, and causes said magnesium to react with oxygen in said cavities to create a reduced pressure therein.
Claim 8
Dependent Claim
57 words
A method in accordance with claim 5 wherein said sleeve and said fusible elements are glass and where in the step of applying heat further causes said magnesium to react with the surfaces of said glass sleeve and fusible elements to reduce the same and form reaction products which constitute a part of said conductive cermet layer.
Claim 9
Dependent Claim
32 words
A method in accordance with claim 6 further comprising the steps of urging said first ends of said first and second leads toward said impedance element during the step of applying heat.
Claim 10
Dependent Claim
33 words
A method in accordance with claim 7 wherein the step of disposing magnesium in the open ends of said sleeve comprises disposing a magnesium wafer adjacent to each end of said impedance element.
Claim 11
Independent Claim
198 words
A method of forming an encapsulated resistor comprising the steps of providing a resistor blank having a predetermined value of resistance and having electrical terminals at opposed ends thereof, disposing a sleeve of fusible encapsulating material about said resistor blank so that first and second open ends thereof extend beyond said blank, disposing a wafer of magnesium adjacent to each end of said resistor blank, providing first and second external leads, inserting a first end of said first lead into the first end of said sleeve, inserting the first end of said second lead into the second end of said sleeve, disposing first and second fusible elements about said first and second leads, respectively, intermediate the ends thereof, said fusible elements having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to Those portions of the assembly so formed including said fusible elements and the adjacent ends of said sleeve to cause said fusible elements to form hermetic seals with their corresponding leads and with the corresponding ends of said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer between said electrical terminals and said leads.
Claim 12
Independent Claim
198 words
A method of forming an encapsulated resistor comprising the steps of providing a resistor blank having a predetermined value of resistance and having electrical terminals at opposed ends thereof, disposing a sleeve of fusible encapsulating material about said resistor blank so that first and second open ends thereof extend beyond said blank, disposing a wafer of magnesium adjacent to each end of said resistor blank, providing first and second external leads, inserting a first end of said first lead into the first end of said sleeve, inserting the first end of said second lead into the second end of said sleeve, disposing first and second fusible elements about said first and second leads, respectively, intermediate the ends thereof, said fusible elements having a coefficient of thermal expansion similar to that of said encapsulating sleeve material, and applying heat to Those portions of the assembly so formed including said fusible elements and the adjacent ends of said sleeve to cause said fusible elements to form hermetic seals with their corresponding leads and with the corresponding ends of said sleeve, and to cause said magnesium to vaporize and form a conductive cermet layer between said electrical terminals and said leads.
Claim 13
Dependent Claim
110 words
A method in accordance with claim 9 wherein said sleeve and said fusible elements are glass and wherein said fusible elements are spaced from the ends of said impedance element so that the step of applying heat results in the formation of a cavity at each end of said blank between said blank, the adjacent end of said sleeve and said fusible element and further causes said magnesium to react with oxygen in said cavities to create a reduced pressure therein and to react with the surfaces of said glass sleeve and fusible elements to reduce the same and form reaction products which constitute a part of said cermet layer.
Claim 14
Dependent Claim
52 words
A method in accordance with claim 10 wherein said first ends of said leads are provided with enlarged end portions, said method further comprising the step of urging the enlarged end portions of said first and second leads into engagement with the magnesium wafers adjacent thereto during the step of applying heat.
Claim 15
Dependent Claim
124 words
An encapsulated impedance device comprising an impedance element having at least one electrical terminal, an external lead having an end thereof disposed adjacent to said electrical terminal, a sleeve of encapsulating material disposed about said impedance element and said end of said lead, a fusible element disposed about said lead intermediate the ends thereof having a coefficient of thermal expansion compatible with that of said encapsulating sleeve material, said fusible element being fused to said lead and to the corresponding end of said sleeve, and a conductive cermet layer disposed upon the inner surfaces of the end of said sleeve and said fusible element, said cermet layer including magnesium and magnesium oxide and providing an electrical connection between said electrical terminal and said lead.
Claim 16
Dependent Claim
124 words
An encapsulated impedance device comprising an impedance element having at least one electrical terminal, an external lead having an end thereof disposed adjacent to said electrical terminal, a sleeve of encapsulating material disposed about said impedance element and said end of said lead, a fusible element disposed about said lead intermediate the ends thereof having a coefficient of thermal expansion compatible with that of said encapsulating sleeve material, said fusible element being fused to said lead and to the corresponding end of said sleeve, and a conductive cermet layer disposed upon the inner surfaces of the end of said sleeve and said fusible element, said cermet layer including magnesium and magnesium oxide and providing an electrical connection between said electrical terminal and said lead.
Claim 17
Dependent Claim
44 words
An impedance element in accordance with claim 12 wherein a cavity is defined by the end of said impedance element and the inner surfaces of said fusible element and adjacent end of said sleeve, the pressure in said cavity being lower than ambient pressure.
Claim 18
Dependent Claim
48 words
An encapsulated impedance device in accordance with claim 13 wherein said sleeve and fusible element consist of glass and said cermet layer disposed upon said sleeve and fusible element includes reaction products that result from reduction of the surfaces of said glass sleeve and fusible element by magnesium.
Claim 19
Dependent Claim
159 words
An encapsulated impedance device comprising an impedance element having first and second electrical terminals at opposed ends thereof, a first external lead having an end thereof disposed adjacent to said first electrical terminal, a second external lead having an end thereof disposed adjacent to said second electrical terminal, a sleeve of encapsulating material disposed about said impedance element and said ends of said first and second leads, first and second fusible elements disposed about said first and second leads, respectively, intermediate the ends thereof, the coefficient of thermal expansion of said fusible elements being compatible with that of said encapsulating sleeve material, each of said fusible elements being fused to its corresponding lead and to the corresponding end of said sleeve, and a conductive cermet layer disposed upon the inner surfaces of the ends of said sleeve and said fusible elements, said cermet layer including magnesium oxide and providing an electrical connection between said electrical terminals and associated leads.
Claim 20
Dependent Claim
159 words
An encapsulated impedance device comprising an impedance element having first and second electrical terminals at opposed ends thereof, a first external lead having an end thereof disposed adjacent to said first electrical terminal, a second external lead having an end thereof disposed adjacent to said second electrical terminal, a sleeve of encapsulating material disposed about said impedance element and said ends of said first and second leads, first and second fusible elements disposed about said first and second leads, respectively, intermediate the ends thereof, the coefficient of thermal expansion of said fusible elements being compatible with that of said encapsulating sleeve material, each of said fusible elements being fused to its corresponding lead and to the corresponding end of said sleeve, and a conductive cermet layer disposed upon the inner surfaces of the ends of said sleeve and said fusible elements, said cermet layer including magnesium oxide and providing an electrical connection between said electrical terminals and associated leads.
Claim 21
Dependent Claim
44 words
An encapsulated impedance device in accordance with claim 15 wherein cavities are defined by the ends of said impedance element and the inner surfaces of said fusible elements and Adjacent ends of said sleeve, the pressure in said cavity being lower than ambient pressure.
Claim 22
Dependent Claim
48 words
An encapsulated impedance device in accordance with claim 16 wherein said sleeve and fusible elements consist of glass and said cermet layer disposed upon said sleeve and fusible elements includes reaction products that result from reduction of the surfaces of said glass sleeves and fusible elements by magnesium.
Claim 23
Dependent Claim
23 words
An encapsulated impedance device in accordance with claim 17 wherein said impedance element is a resistor blank having a predetermined value of resistance.
Claim 24
Dependent Claim
36 words
An encapsulated impedance device in accordance with claim 18 wherein the ends of said first and second external leads that are disposed adjacent to said first and second electrical terminals are provided with enlarged end portions.
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) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |