US4855647A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flashlight with soft turn on control
Assignee: Spectrum Brands Inc
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Filing: 1987-04-14
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Granted: 1989-08-08
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Expires: 2007-04-14
Abstract
Abstract A flashlight is provided with a special circuit for limiting the surge current through the flashlight bulb. The circuit includes a secondary incandescent filament used to energize a transistor gradually upon the activation of flashlight. The transistor in turn gradually energizes the main bulb.
Inventors
- 👤 David R. Schaller
- 👤 El-Sayed Megahed
- 👤 Charles E. Samson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 14:47
CPC Classifications
H; H05; H05B; H05B39/00; H05B39/02
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
97 words
A flashlight comprising: (a) a housing; (b) a plurality of batteries disposed in said housing; (c) a primary light bulb; (d) a manual switch for selectively energizing said primary bulb with said batteries; and (e) control means responsive to said manual switch for controlling current flow through said primary light bulb, said control means being provided to reduce current inrush to said primary bulb, said control means including a transistor connected in series with said primary light bulb and a biasing network for controlling the operation of said transistor, said biasing network including a thermal resistance element.
Claim 2
Dependent Claim
97 words
A flashlight comprising: (a) a housing; (b) a plurality of batteries disposed in said housing; (c) a primary light bulb; (d) a manual switch for selectively energizing said primary bulb with said batteries; and (e) control means responsive to said manual switch for controlling current flow through said primary light bulb, said control means being provided to reduce current inrush to said primary bulb, said control means including a transistor connected in series with said primary light bulb and a biasing network for controlling the operation of said transistor, said biasing network including a thermal resistance element.
Claim 3
Dependent Claim
16 words
The flashlight of claim 1 wherein said time variant resistance element includes a secondary light bulb.
Claim 4
Dependent Claim
72 words
A flashlight comprising; (a) a primary light bulb; (b) a manual switch for activating the light bulb from a power source; (c) an electronic switch connected in series with said primary light bulb; and (d) a temperature variant resistant element for controlling said electronic switch, said element cooperating with said manual switch and said electronic switch to limit the surge current through said primary light bulb when said manual switch is activated.
Claim 5
Dependent Claim
72 words
A flashlight comprising; (a) a primary light bulb; (b) a manual switch for activating the light bulb from a power source; (c) an electronic switch connected in series with said primary light bulb; and (d) a temperature variant resistant element for controlling said electronic switch, said element cooperating with said manual switch and said electronic switch to limit the surge current through said primary light bulb when said manual switch is activated.
Claim 6
Dependent Claim
16 words
The flashlight of claim 3 wherein said temperature variant resistance element is a secondary light bulb.
Claim 7
Dependent Claim
12 words
The flashlight of claim 4 wherein said electronic switch is a transistor.
Claim 8
Dependent Claim
19 words
The flashlight of claim 5 further comprising a resistor coupled with said secondary light bulb for biasing said transistor.
Claim 9
Dependent Claim
36 words
The flashlight of claim 6 wherein said secondary light bulb has a rated voltage and wherein after said primary light bulb is activated, said secondary light bulb is operated at a voltage below said rated voltage.
Claim 10
Dependent Claim
16 words
The flashlight of claim 6 wherein said primary and secondary bulbs are provided in separate envelopes.
Claim 11
Dependent Claim
17 words
The flashlight of claim 6 wherein said primary and secondary bulbs are provided in a common envelope.
Claim 12
Dependent Claim
17 words
The flashlight of claim 6 further comprising capacitive means for slowing the operation of said electronic switch.
Claim 13
Dependent Claim
81 words
A flashlight comprising: (a) a housing; (b) a power source disposed within said housing; (c) primary light generating means; (d) activating means for selectively connecting said power source to said primary light generating means; and (e) control means for controlling the initial current surge through said primary light generating means resulting from said activation, said control circuit including an electronic switch and biasing means for controlling the current flow through said electronic switch, said biasing means including a time-variant resistance element.
Claim 14
Dependent Claim
81 words
A flashlight comprising: (a) a housing; (b) a power source disposed within said housing; (c) primary light generating means; (d) activating means for selectively connecting said power source to said primary light generating means; and (e) control means for controlling the initial current surge through said primary light generating means resulting from said activation, said control circuit including an electronic switch and biasing means for controlling the current flow through said electronic switch, said biasing means including a time-variant resistance element.
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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) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |