US3934333A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of constructing bilateral heater unit
Assignee: Individual
•
Filing: 1974-11-26
•
Granted: 1976-01-27
•
Expires: 1994-11-26
Abstract
Abstract A heater unit of bilateral construction is formed by forming a resistor assembly of a resistor helix extending between cylindrical terminals and overlapping the same, inserting the assembly in a sheath tube, filling the tube with MgO powder, placing laminated mica end plugs over the terminals and extending into the ends of the tube, bending the tube into a U-shape, pressing the legs of the U together and feeding the pressed unit through swaging dies to deform the tube over the entire length thereof to provide a heater unit of substantially circular cross section and having two legs of substantially semicircular cross section. The resistor helix in the area of the leg portions has a cross-sectional shape corresponding to the cross-sectional shape of the sheath and the terminals and mica plugs within the sheath are flattened to provide a similar cross-sectional shape thereby locking the terminals within the sheath.
Inventors
- 👤 John W. Churchill
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:38
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/40; H05B3/42; H05B3/48; H05B3/52; H05B3/02; H05B3/06; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49083; Y10T29/49087; Y10T29/49089; Y10T29/49091; Y10T29/49098
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
193 words
A method of forming a heater unit comprising the steps of forming a resistor assembly by placing each end of an elongated resistor helix over respective end portions of cylindrical metal terminals such that the helix is detachably secured to the respective terminals and extends therebetween, arranging the resistor assembly in a metal tubular sheath such that the assembly extends in the longitudinal direction of the sheath, filling the sheath with granulated powdered insulating material, capping the ends of the tubular sheath with end plugs which are sized for a slide fit into the sheath and a slide fit around the cylindrical terminals which extend through the plugs, and deforming the tubular sheath over the entire length thereof to compact the powdered insulating material such that the end plugs and the metal terminals are deformed to a shape corresponding to the shape of the sheath in the region of the end plugs and metal terminals with the end plugs and terminals becoming lockingly secured within the sheath, at least a portion of the sheath in the region of the end plugs together with at least a portion of the end plugs and the
Claim 2
Independent Claim
193 words
A method of forming a heater unit comprising the steps of forming a resistor assembly by placing each end of an elongated resistor helix over respective end portions of cylindrical metal terminals such that the helix is detachably secured to the respective terminals and extends therebetween, arranging the resistor assembly in a metal tubular sheath such that the assembly extends in the longitudinal direction of the sheath, filling the sheath with granulated powdered insulating material, capping the ends of the tubular sheath with end plugs which are sized for a slide fit into the sheath and a slide fit around the cylindrical terminals which extend through the plugs, and deforming the tubular sheath over the entire length thereof to compact the powdered insulating material such that the end plugs and the metal terminals are deformed to a shape corresponding to the shape of the sheath in the region of the end plugs and metal terminals with the end plugs and terminals becoming lockingly secured within the sheath, at least a portion of the sheath in the region of the end plugs together with at least a portion of the end plugs and the
Claim 3
Dependent Claim
35 words
A method according to claim 1, wherein the step of deforming the sheath includes compacting the powdered insulation to force the wire helix overlapping the end portions of the metal terminals to form depressions in
Claim 4
Dependent Claim
90 words
A method according to claim 1, further comprising after the step of capping the ends of the tubular sheath, bending the tubular sheath having the resistor assembly and powdered insulating material therein into the shape of a U, pressing the legs of the U together while maintaining the same tube diameter, and then performing the step of deforming the tubular sheath over the entire length thereof to provide a heater unit having a substantially circular cross section formed by two substantially semicircular parallel extending leg portions interconnected by a portion
Claim 5
Dependent Claim
23 words
A method according to claim 3, wherein the step of deforming includes providing a substantially zero internal return bend radius at the internal
Claim 6
Dependent Claim
53 words
A method according to claim 4, wherein the step of deforming includes deforming the resistor helix along the extent of the leg portions to a substantially semicircular cross-section shape corresponding to the cross-sectional shape of the leg portions, and maintaining sufficient insulation between the resistor helix and the sheath to insulate and space
Claim 7
Dependent Claim
81 words
A method according to claim 5, wherein the step of deforming includes deforming the resistor helix in the area of the return bend to a cross-sectional shape corresponding to the cross-sectional shape of the sheath such that the resistor helix has a substantially circular shape in the plane of the flat portion of the semicircular cross section of the leg portions while maintaining sufficient outer insulation between the resistor helix and the sheath to insulate and space the helix from the
Claim 8
Dependent Claim
36 words
A method according to claim 6, wherein the step of deforming includes compacting the powdered insulation to force the wire helix overlapping the end portions of the metal terminals to form depressions in the surface of
Claim 9
Dependent Claim
68 words
A method according to claim 2, including the step of utilizing cylindrical metal terminals in forming the resistor assembly, the terminals having an axially extending hollow portion therein, and placing a stranded flexible lead wire in the hollow portion of each of the metal terminals such that the lead wire extends outwardly beyond the end of the tubular sheath when the resistor assembly is placed within the tubular
Claim 10
Dependent Claim
11 words
A method according to claim 7, wherein the powdered insulating material
Claim 11
Dependent Claim
26 words
A method according to claim 1, wherein the step of deforming the portion of the sheath out of round includes deforming the sheath to form a
Claim 12
Independent Claim
192 words
A method of forming a heater unit comprising the steps of forming a resistor assembly by placing each end of an elongated resistor helix over respective end portions of cylindrical metal terminals such that the helix is detachably secured to the respective terminals and extends therebetween, arranging the resistor assembly in a metal tubular sheath such that the assembly extends in the longitudinal direction of the sheath, filling the sheath with granulated powdered insulating material, capping the ends of the tubular sheath with end plugs which are sized for a slide fit into the sheath and a slide fit around the cylindrical terminals which extend through the plugs, bending the tubular sheath having the resistor assembly and powdered insulating material therein into the shape of a U, pressing the legs of the U together while maintaining the same tube diameter, and then deforming the tubular sheath over the entire length thereof to compact the powdered insulating material and to provide a heater unit having a substantially circular cross section formed by two substantially semicircular parallel extending leg portions interconnected by a portion of the tubular sheath having a 180° outer return bend.
Claim 13
Independent Claim
192 words
A method of forming a heater unit comprising the steps of forming a resistor assembly by placing each end of an elongated resistor helix over respective end portions of cylindrical metal terminals such that the helix is detachably secured to the respective terminals and extends therebetween, arranging the resistor assembly in a metal tubular sheath such that the assembly extends in the longitudinal direction of the sheath, filling the sheath with granulated powdered insulating material, capping the ends of the tubular sheath with end plugs which are sized for a slide fit into the sheath and a slide fit around the cylindrical terminals which extend through the plugs, bending the tubular sheath having the resistor assembly and powdered insulating material therein into the shape of a U, pressing the legs of the U together while maintaining the same tube diameter, and then deforming the tubular sheath over the entire length thereof to compact the powdered insulating material and to provide a heater unit having a substantially circular cross section formed by two substantially semicircular parallel extending leg portions interconnected by a portion of the tubular sheath having a 180° outer return bend.
References Cited (Backward Citations)
US1960221A
Cited
GB466060A
Cited
US2157884A
Cited
US2375058A
Cited
US2483839A
Cited
US2876322A
Cited
US2933805A
Cited
US2846537A
Cited
US3007235A
Cited
US3330034A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-26 | 1979-07-28 | 1980-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-26 | 1983-07-28 | 1984-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-26 | 1987-07-28 | 1988-01-27 | $7700.00 | Window Closed / Lapsed |