US3996437A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vacuum contactor for motor control and method of making
Assignee: Cutler Hammer Inc
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Filing: 1973-12-03
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Granted: 1976-12-07
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Expires: 1993-12-03
Abstract
Abstract A vacuum contactor for motor control applications and method of making the same that produces a switch of minimum size and extremely long mechanical life. This method comprises the step of heating the vacuum assembly to not over 450° C during the evacuation process thereby allowing use of welded diaphragm bellows having the attendant advantages of much smaller size and longer life for a given length of stroke as compared to formed bellows. Because the operating conditions for motor control applications do not require as high voltage and current breakdown levels and thus the residual gas level inside the vacuum contactor enclosure need not be as low as in the case of circuit breaker (interrupter) applications, limiting the heating to not over 450° C allows use of AM-350 stainless steel welded diaphragm bellows without sacrificing its required mechanical life. Furthermore, the bellows shield is designed to achieve minimum current chopping and at the same time maintain high current interruption capabilities. Two types of vacuum switch configurations made according to this method are disclosed.
Inventors
- 👤 Amos Selzer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 13:22
CPC Classifications
H; H01; H01H; H01H33/00; H01H33/60; H01H33/66; H01H33/662; H01H33/66238
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
280 words
A method of making a vacuum contactor from a plurality of prepared parts including an enclosure comprising a pair of spaced apart apertured plates and an envelope comprising an electrical insulator for closing the space between the plates and insulating them from one another, a stationary contact support having a contact portion at one end thereof and adapted to be mounted in the aperture in one of said plates so as to extend into the enclosure, a movable contact support having a contact portion at one end thereof and adapted to extend freely through the aperture in the other plate for engaging the stationary contact, a welded diaphragm bellows adapted to seal the space between the movable contact support and said other plate, and means comprising an evacuation tube providing access into the enclosure to remove air therefrom comprising the steps: braze said stationary contact support within said aperture in said one plate to provide a hermetic seal therebetween; weld the bellows to the movable contact support and to said other plate to seal the space therebetween while allowing resilient movement of the movable contact support in the aperture in said other plate; weld the envelope to the two spaced plates to provide a hermetic seal therebetween and to hermetically seal the enclosure except for the evacuation tube; bake the vacuum contactor at a temperature up to 450° C while maintaining the inside of the enclosure at a predetermined vacuum by drawing air through said evacuation tube and maintaining the outside thereof in an inert gas environment; and after a predetermined time of baking close the evacuation tube to completely seal the contacts on the inside from the external atmosphere.
Claim 2
Independent Claim
280 words
A method of making a vacuum contactor from a plurality of prepared parts including an enclosure comprising a pair of spaced apart apertured plates and an envelope comprising an electrical insulator for closing the space between the plates and insulating them from one another, a stationary contact support having a contact portion at one end thereof and adapted to be mounted in the aperture in one of said plates so as to extend into the enclosure, a movable contact support having a contact portion at one end thereof and adapted to extend freely through the aperture in the other plate for engaging the stationary contact, a welded diaphragm bellows adapted to seal the space between the movable contact support and said other plate, and means comprising an evacuation tube providing access into the enclosure to remove air therefrom comprising the steps: braze said stationary contact support within said aperture in said one plate to provide a hermetic seal therebetween; weld the bellows to the movable contact support and to said other plate to seal the space therebetween while allowing resilient movement of the movable contact support in the aperture in said other plate; weld the envelope to the two spaced plates to provide a hermetic seal therebetween and to hermetically seal the enclosure except for the evacuation tube; bake the vacuum contactor at a temperature up to 450° C while maintaining the inside of the enclosure at a predetermined vacuum by drawing air through said evacuation tube and maintaining the outside thereof in an inert gas environment; and after a predetermined time of baking close the evacuation tube to completely seal the contacts on the inside from the external atmosphere.
Claim 3
Dependent Claim
17 words
The invention defined in claim 1, wherein said predetermined time of baking is two to twelve hours.
Claim 4
Dependent Claim
30 words
The invention defined in claim 1, wherein said predetermined vacuum at which the inside of said enclosure is maintained is a pressure range of 10.sup. -2 to 10.sup. -8 torr.
Claim 5
Dependent Claim
27 words
The invention defined in claim 1, wherein said brazing steps comprise: maintained a vacuum or inert gas environment for said brazing operations while they are being performed.
Claim 6
Dependent Claim
21 words
The invention defined in claim 1, wherein said welding steps comprise use of a TIG weld or electron beam welding process.
Claim 7
Independent Claim
283 words
A method of making a vacuum contactor from a plurality of preformed parts including an enclosure comprising an upper apertured plate and a lower apertured plate spaced therefrom and an envelope having an electrical insulating section for closing the space between the plates and insulating them from one another, a stationary contact structure including a contact supporting stem and a contact adapted to be secured in the aperture in the upper plate, a movable contact structure including a contact supporting stem and a bellows plate and a bellows shield and a contact adapted to extend freely through the aperture in the lower plate for engaging the stationary contact, a welded diaphragm bellows adapted to seal the comprising an evacuation tube providing access into the enclosure for removing air therefrom comprising the steps: braze the stationary contact to its supporting stem and the latter in the aperture in the upper plate to provide a hermetic seal therebetween; braze the bellows plate to the movable contact supporting stem, the bellows shield to the bellows plate and the movable contact to the bellows shield stacked in that order; weld the bellows to the bellows plate and to the lower plate to provide a hermetic seal therebetween; weld the envelope to the peripheral parts of the upper and lower plates to hermetically seal the enclosure except for the evacuation tube; bake the vacuum contactor 2-12 hours at a temperature up to 450° C while maintaining the inside of the enclosure at a pressure range of 10.sup. -2 to 10.sup. -8 torr and the outside thereof in vacuum or inert gas environment; and close the evacuation tube to completely seal the inside of the enclosure from the atmosphere.
Claim 8
Independent Claim
283 words
A method of making a vacuum contactor from a plurality of preformed parts including an enclosure comprising an upper apertured plate and a lower apertured plate spaced therefrom and an envelope having an electrical insulating section for closing the space between the plates and insulating them from one another, a stationary contact structure including a contact supporting stem and a contact adapted to be secured in the aperture in the upper plate, a movable contact structure including a contact supporting stem and a bellows plate and a bellows shield and a contact adapted to extend freely through the aperture in the lower plate for engaging the stationary contact, a welded diaphragm bellows adapted to seal the comprising an evacuation tube providing access into the enclosure for removing air therefrom comprising the steps: braze the stationary contact to its supporting stem and the latter in the aperture in the upper plate to provide a hermetic seal therebetween; braze the bellows plate to the movable contact supporting stem, the bellows shield to the bellows plate and the movable contact to the bellows shield stacked in that order; weld the bellows to the bellows plate and to the lower plate to provide a hermetic seal therebetween; weld the envelope to the peripheral parts of the upper and lower plates to hermetically seal the enclosure except for the evacuation tube; bake the vacuum contactor 2-12 hours at a temperature up to 450° C while maintaining the inside of the enclosure at a pressure range of 10.sup. -2 to 10.sup. -8 torr and the outside thereof in vacuum or inert gas environment; and close the evacuation tube to completely seal the inside of the enclosure from the atmosphere.
Claim 9
Dependent Claim
25 words
The invention defined in claim 6, wherein said brazing steps comprise maintaining the work area in a vacuum or inert gas environment while being brazed.
Claim 10
Dependent Claim
21 words
The invention defined in claim 6, wherein said welding steps comprise use of a TIG weld or electron beam welding process.
Claim 11
Dependent Claim
149 words
A vacuum contactor for motor control applications comprising: an evacuated enclosure including a pair of spaced apertured circular plates and an insulating envelope connected and sealed to the peripheral edges of said plates to enclose the space therebetween; a stationary contact extending through the aperture in one of said plates and sealed to the rim of said aperture; a movable contact extending through the aperture in the other plate for engaging the stationary contact; means guiding said movable contact for axial movement in said other plate aperture; a short cylindrical welded diaphragm bellows composed of long mechanical operation life material connected and sealed between said movable contact and said other plate to allow relative movement while sealing the enclosure, said welded diaphragm bellows affording a much greater contact opening stroke for its size to provide a minimum size of contactor having a very long life for motor control applications.
Claim 12
Dependent Claim
149 words
A vacuum contactor for motor control applications comprising: an evacuated enclosure including a pair of spaced apertured circular plates and an insulating envelope connected and sealed to the peripheral edges of said plates to enclose the space therebetween; a stationary contact extending through the aperture in one of said plates and sealed to the rim of said aperture; a movable contact extending through the aperture in the other plate for engaging the stationary contact; means guiding said movable contact for axial movement in said other plate aperture; a short cylindrical welded diaphragm bellows composed of long mechanical operation life material connected and sealed between said movable contact and said other plate to allow relative movement while sealing the enclosure, said welded diaphragm bellows affording a much greater contact opening stroke for its size to provide a minimum size of contactor having a very long life for motor control applications.
Claim 13
Dependent Claim
23 words
The invention defined in claim 9, wherein said long mechanical operation life material in said welded diaphragm bellows is AM 350 stainless steel.
Claim 14
Dependent Claim
51 words
The invention defined in claim 9, wherein said insulated envelope comprises: a cylindrical member having a central section of ceramic material for electrically insulating the stationary and movable contacts from one another and having opposite end rings sealed to said ceramic section and welded to the peripheral edges of said plates.
Claim 15
Dependent Claim
81 words
The invention defined in claim 9, wherein said insulated envelope comprises: a third apertured circular plate spaced between said one plate and said other plate; a cylindrical member having a central electrically insulating ceramic section and opposite end rings sealed to said ceramic section and connected to the peripheral edge of said one plate and the rim of the aperture in said third plate; and a metal cylinder connected between the peripheral edges of said other plate and said third plate.
Claim 16
Dependent Claim
51 words
The invention defined in claim 12, wherein: said insulating cylindrical member has a relatively small diameter and serves to insulate the contacts from one another; and said metal cylinder has a relatively large diameter and serves to condense the arc products so as to keep them away from the insulating cylinder.
Claim 17
Dependent Claim
37 words
The invention defined in claim 9, wherein said movable contact comprises: a metal bellows shield extending from the movable contact around the adjacent end portion of the stationary contact to shield the bellows from the arc products.
Claim 18
Dependent Claim
39 words
The invention defined in claim 14, wherein said enclosure comprises: a cylindrical metal shield secured to said one plate and suspended therefrom between said insulating envelope and said bellows shield to shield the arc products from said insulating envelope.
Claim 19
Dependent Claim
40 words
The invention defined in claim 14, wherein said metal bellows shield comprises: a metal member having an inner wall spaced from the nearest point of the stationary contact an optimum distance to achieve minimum current chopping and maximum current interruption.
Claim 20
Dependent Claim
39 words
The invention defined in claim 16, wherein: said inner wall of said metal bellows shield member is provided with a height generally parallel to said stationary contact that is a function of the maximum opening gap between said contacts.
Claim 21
Dependent Claim
29 words
The invention defined in claim 17, wherein: said inner wall is provided with a height in the range of one-half to six times the length of said opening gap.
Claim 22
Dependent Claim
30 words
The invention defined in claim 16, wherein: said inner wall is spaced from said nearest point of the stationary contact one-half to six times the length of said opening gap.
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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) | 1979-12-07 | 1980-06-07 | 1980-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-12-07 | 1984-06-07 | 1984-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-12-07 | 1988-06-07 | 1988-12-07 | $7700.00 | Window Closed / Lapsed |