Patent US4857783A successfully refreshed from Google Patents.
US4857783A
Expired / Lapsed
US
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Brushless direct current motor incorporating a magnetically influenced switch
Assignee: Individual
•
Filing: 1988-02-18
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Granted: 1989-08-15
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Expires: 2008-02-18
Abstract
Abstract A brushless direct current (DC) motor operating on the interaction of a permanent magnet rotor with an electromagnetic torque-inducing stator coil. Current applied to an electromagnetic torque-inducing stator coil is controlled by a magnetically influenced reed or leaf switch.
Inventors
- 👤 Randall K. Prunkard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:45
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/06
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
134 words
A brushless DC motor comprising: a source of direct electrical current; a ferrous metal rotational output shaft; an annular, unitary, flat, two-pole permanent magnet mounted upon said output shaft transversely to the axis of rotation; a stator coil provided with a ferrous metal core located within the magnetic field of said two-pole permanent magnet and energized by said source of direct electrical current; and a magnetically influenced switch mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, and connected in series with said source of direct electrical current and said stator coil for controlling the current applied to said coil based upon the position of said two-pole permanent magnet with respect to said switch, whereby said switch is operated in a smooth manner.
Claim 2
Dependent Claim
134 words
A brushless DC motor comprising: a source of direct electrical current; a ferrous metal rotational output shaft; an annular, unitary, flat, two-pole permanent magnet mounted upon said output shaft transversely to the axis of rotation; a stator coil provided with a ferrous metal core located within the magnetic field of said two-pole permanent magnet and energized by said source of direct electrical current; and a magnetically influenced switch mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, and connected in series with said source of direct electrical current and said stator coil for controlling the current applied to said coil based upon the position of said two-pole permanent magnet with respect to said switch, whereby said switch is operated in a smooth manner.
Claim 3
Dependent Claim
87 words
The brushless DC motor is accordance with claim 1 wherein said magnetically influenced switch comprises: a double pole double throw leaf switch resiliently biased in the closed position; and a permanent magnet fixedly attached to the end of said leaf switch; wherein said leaf switch is mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, to alternately open and close in response to an alternating magnetic field, whereby said switch is operated in a smooth manner.
Claim 4
Dependent Claim
67 words
The brushless DC motor in accordance with claim 1 wherein said magnetically influenced switch comprises: a single-pole-single-throw reed switch resiliently biased in the open position; and a semicircular permanent magnet fixedly attached to the said two-pole magnet; wherein said reed switch is mounted within the magnetic field of said semicircular permanent magnet to alternately open and close said reed switch in response to an alternating magnetic field.
Claim 5
Dependent Claim
14 words
The brushless DC motor in accordance with claim 1 wherein said switch is polarized.
Claim 6
Dependent Claim
17 words
The brushless DC motor in accordance wtih claim 2 wherein said magnetically influenced switch is magnetically polarized.
Claim 7
Dependent Claim
134 words
A brushless DC motor comprising: a source of direct electrical current; a ferrous metal rotational output shaft; an annular, two-part, flat, two-pole permanent magnet mounted upon said output shaft transversely to the axis of rotation; a stator coil provided with a ferrous metal core located within the magnetic field of said two-pole permanent magnet and energized by said source of direct electrical current; and a magnetically influenced switch mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, and connected in series with said source of direct electrical current and said stator coil for controlling the current applied to said coil based upon the position of said two-pole permanent magnet with respect to said switch, whereby said switch is operated in a smooth manner.
Claim 8
Dependent Claim
134 words
A brushless DC motor comprising: a source of direct electrical current; a ferrous metal rotational output shaft; an annular, two-part, flat, two-pole permanent magnet mounted upon said output shaft transversely to the axis of rotation; a stator coil provided with a ferrous metal core located within the magnetic field of said two-pole permanent magnet and energized by said source of direct electrical current; and a magnetically influenced switch mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, and connected in series with said source of direct electrical current and said stator coil for controlling the current applied to said coil based upon the position of said two-pole permanent magnet with respect to said switch, whereby said switch is operated in a smooth manner.
Claim 9
Dependent Claim
79 words
The brushless DC motor in accordance with claim 6 wherein said magnetically influenced switch comprises a two-pole leaf switch resiliently biased in the closed position: and a permanent magnet fixedly attached to the end of said leaf switch; wherein said leaf switch is mounted within the magnetic field of said two-pole permanent magnet, but removed from the magnetic influence of said stator coil, to alternately open and close said leaf switch smoothly in response to an alternating magnetic field.
Claim 10
Dependent Claim
81 words
The brushless DC motor in accordance with claim 6, wherein said magnetically influenced switch comprises: a single pole-single throw reed switch resiliently biased in the open position and a semi-circular permanent magnet fixedly attached to the said two-part, two-pole magnet wherein said reed switch is mounted within the magnetic field of said semi-circular permanent magnet, but removed from the magnetic influence of said stator coil, to alternately open and close said reed switch smoothly in response to an alternating magnetic field.
Claim 11
Dependent Claim
17 words
The brushless DC motor in accordance with claim 6 wherein said magnetically influenced switch is magnetically polarized.
Claim 12
Dependent Claim
18 words
The brushless DC motor in accordance with claim 7 wherein said magnetically influenced leaf switch is magnetically polarized.
References Cited (Backward Citations)
US2459930A
Cited
US2606222A
Cited
US2861204A
Cited
US3297891A
Cited
US3688136A
Cited
US3662196A
Cited
US4517477A
Cited
US4311933A
Cited
US4357563A
Cited
US4642534A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-14 | 1993-02-13 | 1993-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-14 | 1997-02-13 | 1997-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-14 | 2001-02-13 | 2001-08-15 | $7700.00 | Window Closed / Lapsed |