Patent US3693250A successfully refreshed from Google Patents.
US3693250A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making metallic sheathed cables with foam cellular polyolefin insulation and method of making
Assignee: Citizens and Southern National Bank
•
Filing: 1970-07-20
•
Granted: 1972-09-26
•
Expires: 1990-07-20
Abstract
Abstract This specification discloses a method of making a metallic sheathed electrical cable having foamed cellular polyolefin dielectric insulation which is fusion-bonded to the inside of an annealed sheath to obtain better electrical and mechanical characteristics. The sheath is applied to a foam-insulated core and then sunk down by drawing through a die or reducing rolls to make the tube fit the insulated core snugly. Controlled heating of the sheathing melts the part of the insulation, or adhesive material, when used, which is in contact with the sheath to produce the fusion bond. The heating period is short and is followed by a quench. This controlled heating and cooling is also used to anneal the metallic sheath.
Inventors
- 👤 William J Brorein
- 👤 Fred F Polizzano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:19
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/22; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49826; Y10T29/49828; Y10T29/53; Y10T29/53126; Y10T29/5313; Y10T29/532; Y10T29/53243; Y10T74/00; Y10T74/20; Y10T74/20396; Y10T74/20402; Y10T74/20456
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
82 words
The method described in claim 1 characterized by compressing the foamed insulation with firm contact against the metal sheath and then relieving at least some of the compression and causing the insulation to fill any irregularities in the inner surface of the sheath by heating the insulation to a temperature that softens to a flowable condition the portion of the insulation which is in contact with the sheath, whereby the insulation flows into any irregularities in the inside surface of the sheath.
Claim 2
Dependent Claim
30 words
The method described in claim 2 characterized by the tube being heated quickly and then rapidly cooled to limit the depth of penetration of the melt of the foam insulation.
Claim 3
Dependent Claim
79 words
The method described in claim 1 characterized by surrounding the foam insulated core progressively with the metal sheath and having the inside diameter of the metal sheath substantially larger than the outside diameter of the core, as the core and sheath advance with continuous motion, sinking the sheath to a diameter that causes the sheath to contact the insulation with controlled pressure after the sinking operation, and controlling the heating time by regulating the rate of said continuous motion.
Claim 4
Dependent Claim
91 words
The method described in claim 4 characterized by applying a pulling force to the sheath to pull it through apparatus that sinks the sheath, applying the heat for fusion bonding at a location beyond the application of the pulling force in the direction in which the sheath is pulled, and pulling the sheath to advance it beyonD the region of heating, this last pulling step being with a force controlled to prevent the sheath from being stressed beyond its yielding point at the elevated temperature during the heating of the sheath.
Claim 5
Dependent Claim
78 words
The method described in claim 1 characterized by coating the insulation with an adhesion-promoting material that bonds to both the insulation and the sheath, forming the sheath into a tube around the insulated core by longitudinally folding a metal strip around the insulated core, welding the seam of the tube closed, and after welding, and some subsequent cooling to a temperature less than melting temperature of the foam, sinking the tube into contact with the adhesive coated core.
Claim 6
Dependent Claim
61 words
The method described in claim 1 characterized by coating the sheath with an adhesive-promoting material that bonds to both the insulation and the sheath, forming the sheath into a tube around the insulated core by longitudinally folding a metal strip around the insulated core, welding the seam of the tube closed, and sinking the tube into contact with the insulated core.
Claim 7
Dependent Claim
36 words
The method described in claim 1 characterized by applying a thermoactivated adhesion-promoting material to the core, sinking the sheath into contact with the adhesion-promoting material, and activating the adhesion-promoting material by applying heat to the sheath.
Claim 8
Dependent Claim
52 words
The method described in claim 1 characterized by covering the core with a first layer of foamed insulation, covering the first layer with an outer layer of softer foamed insulation, applying a metal sheath over the softer insulation with some pressure against the softer insulation, and heating the insulation through the sheath.
Claim 9
Dependent Claim
39 words
The method described in claim 9 characterized by applying sufficient heat to raise the temperature of the sheath to an annealing temperature, and cooling the sheath by a flow of cooling fluid to limit the softening of the insulation.
Claim 10
Dependent Claim
94 words
The method described in claim 10 characterized by the heating of the sheath being divided into two steps including one step that raises the metal of the sheath to an annealing temperature, said step being performed in a heating period of short duration to prevent excessive fusion of the foam within the sheath, and another step that raises the metal of the sheath to a temperature substantially less than the annealing temperature and for a period of longer duration than the first step for obtaining a desired depth of softening of the foamed insulation.
Claim 11
Dependent Claim
128 words
The method described in claim 1 characterized by the method being applied to a cable of from about 1/4 inch to 2 1/2 inches diameter with an aluminum sheath of from about 0.010 to 0.150 inches in thickness, and foamed polyethylene insulation having a specific gravity of approximately 45 percent, advancing the cable and sheath continuously past a heat source, correlating the speed of the cable with the intensity and length of the heat source so as to heat the sheath to a temperature of about 500*-850* F in less than 10 seconds, cooling the tube quickly after reaching that temperature, and maintaining the core and sheath in a straight line during heating and cooling and while passing from the region of heating to the region of cooling.
Claim 12
Dependent Claim
59 words
In the making of electric cable that has a core surrounded by foamed insulated in a snugly fitted metal sheath that puts the foam under compression, the improvement which comprises heating the metal sheath to a given temperature for a period that softens the outside of the foamed insulation to relieve compression and fuse the foam to the sheath.
Claim 13
Dependent Claim
34 words
The method described in claim 13 characterized by bringing the temperature of the metal sheath during at least a part of the heating period to a temperature high enough to anneal the metal sheath.
References Cited (Backward Citations)
US3118800A
Cited
US3344228A
Cited
US3325589A
Cited
US3373244A
Cited
US3365534A
Cited
US3451861A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-26 | 1976-03-27 | 1976-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-26 | 1980-03-27 | 1980-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-26 | 1984-03-27 | 1984-09-26 | $7700.00 | Window Closed / Lapsed |