US4275433A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lighting fitting
Assignee: ISLES
•
Filing: 1979-05-04
•
Granted: 1981-06-23
•
Expires: 1999-05-04
Abstract
Abstract An electrical lighting fitting for a remotely hazardous area comprises two enclosures. The lamp itself is disposed in one enclosure and the control equipment for the lamp is disposed in the other around the axis of the fitting. The two enclosures are thermally insulated from each other and at least the one containing the lamp is maintained at a pressure other than ambient. A pressure switch is associated with this enclosure so that should a break occur in the enclosure this can be sensed and the electrical supply to the lamp removed. The thermal insulation enables the lamp to be run in temperatures which would not otherwise be possible. The enclosure housing of the lamp may be fixed to the remainder of the lamp by springs to enable lamp maintenance without the use of tools.
Inventors
- 👤 James Caldwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:01
CPC Classifications
F; F21; F21V; F21V25/00; F21V25/02; F21V25/04
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
90 words
An electrical lighting fitting comprising: (a) a lamp enclosure containing a lamp, (b) an auxiliary enclosure containing control equipment, (c) means for maintaining said lamp enclosure at a pressure other than ambient pressure, (d) means in said lamp enclosure for detecting a change in pressure therein and for discontinuing electrical supply to the fitting in response to a predetermined pressure change, and (e) means for thermally insulating the auxiliary enclosure from the lamp enclosure so as to immunize temperature increase of the control equipment due to heat from the lamp.
Claim 2
Dependent Claim
90 words
An electrical lighting fitting comprising: (a) a lamp enclosure containing a lamp, (b) an auxiliary enclosure containing control equipment, (c) means for maintaining said lamp enclosure at a pressure other than ambient pressure, (d) means in said lamp enclosure for detecting a change in pressure therein and for discontinuing electrical supply to the fitting in response to a predetermined pressure change, and (e) means for thermally insulating the auxiliary enclosure from the lamp enclosure so as to immunize temperature increase of the control equipment due to heat from the lamp.
Claim 3
Dependent Claim
23 words
An electrical lighting fitting as claimed in claim 1, in which the means for detecting a change in pressure comprises a pressure switch.
Claim 4
Dependent Claim
31 words
An electrical lighting fitting as claimed in claim 2, in which the pressure switch is set to react to a fall in pressure to discontinue the electrical supply to the lamp.
Claim 5
Dependent Claim
31 words
An electrical lighting fitting as claimed in claim 2, in which the pressure switch is set to react to a rise in pressure to discontinue the electrical supply to the lamp.
Claim 6
Dependent Claim
27 words
An electrical lighting fitting as claimed in claim 1, in which the two enclosures are thermally insulated from each other by means of a heat reflecting screen.
Claim 7
Dependent Claim
31 words
An electrical lighting fitting as claimed in claim 5, including, a lamp holder, and in which the screen coaxially surrounds the lamp holder and also serves as a light focussing reflector.
Claim 8
Dependent Claim
33 words
An electrical lighting fitting as claimed in claim 1, in which the lamp is tungsten filament, tungsten ballasted mercury, mercury vapour fluorescent tubes or bulbs, high or low pressure sodium or metal halide.
Claim 9
Dependent Claim
22 words
An electrical lighting fitting as claimed in claim 1, in which the said lamp enclosure is partially defined by a well glass.
Claim 10
Dependent Claim
31 words
An electrical lighting fitting as claimed in claim 1, in which the said lamp enclosure is partially defined by a glass tube closed at its lower end by a glass plate.
Claim 11
Dependent Claim
19 words
An electrical lighting fitting as claimed in claim 9, in which the tube and plate are connected by adhesive.
Claim 12
Dependent Claim
17 words
An electrical lighting fitting as claimed in claim 10, in which the adhesive is an epoxy resin.
Claim 13
Dependent Claim
24 words
An electrical lighting fitting as claimed in claim 8, in which the glass partially defining the said one enclosure is supported in a basket.
Claim 14
Dependent Claim
32 words
An electrical lighting fitting as claimed in claim 12, in which the basket is supported from a plate surrounding and fixed to the body of the fitting by means of detachable springs.
Claim 15
Dependent Claim
45 words
An electrical lighting fitting as claimed in claim 13, in which the basket is also connected to the body of the fitting by elongate flexible elements enabling the glass to be gently lowered from the lamp after detachment of the springs to enable lamp maintenance.
Claim 16
Dependent Claim
21 words
An electrical lighting fitting as claimed in claim 1, in which the supply to the lamp is through a screw connection.
Claim 17
Dependent Claim
21 words
An electrical lighting fitting as claimed in claim 1, in which the supply to the lamp is through a jackplug connection.
References Cited (Backward Citations)
US583959A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |