US3590262A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brush-operating gear for electrical machines
Assignee: Plessey Overseas Ltd
•
Filing: 1969-04-29
•
Granted: 1971-06-29
•
Expires: 1989-04-29
Abstract
Abstract The commutator brushes required for the starter operation of a combined starter-generator are lifted through cam action on completion of the starting operation by a spring-urged ring member which, at the beginning of the starter operation is turned against the spring bias by a rotary solenoid to disengage the brush holders thus allowing the brushes to be applied by application springs. The rotary solenoid is preferably of the type having inner and outer stator poles between which the pole pieces of an annular rotor penetrate, the resulting gaps, or at least one of them, being wedge shaped to maintain throughout the stroke a torque sufficiently high to overcome the progressively loaded return springs, sufficient initial torque being ensured by asymmetric location of the solenoid rotor pole pieces relative to the solenoid stator pole pairs in the deenergized position.
Inventors
- 👤 Bernard R Sheffield
- 👤 Frederick R Jones
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:16
CPC Classifications
H; H02; H02K; H02K23/00; H02K23/52
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
327 words
An electromagnetic device for lifting from the commutator of an electric machine brushes which are normally applied to the commutator by brush-loading spring means, the device comprising lifting means including a brush-lifter ring operable by rotation about the axis of the commutator to withdraw the brushes from contact with the commutator against the action of said brushloading spring means, lifting spring means associated with said brush-lifter ring and urging said ring in the direction of such brush-lifting operation with a torque sufficient to move the ring from an inoperative position allowing the brushes to engage the commutator to an operative position in which the brushes are lifted off the commutator, and a rotary solenoid operative when energized to return said brush-lifter ring from its operative position to its inoperative position against the action of said lifting-spring means, said rotary solenoid including an annular yoke and a magnetizing coil, both coaxial with the commutator, and an armature member coaxially rotatable relative to the yoke and mechanically connected to said brush-lifter ring, said yoke having circumferentially spaced pole pieces projecting at one side of the coil to form, when the coil is energized, magnetic poles of one polarity, and said armature member including armature elements spaced circumferentially for respective cooperation with said pole pieces and each having two surface portions extending approximately in the direction of movement of the element about the common axis of the commutator and armature member and facing respectively one of said pole pieces and a surface portion of said yoke at the opposite side of the coil, the mutually facing surface portions of said armature element and pole piece being inclined relative to the direction of their relative movements over at least part of their length in such manner as to cause the effective airgap between the armature element and yoke to decrease as the armature member moves, when the coil is energized, the brush-lifting ring from its inoperative position towards its operative position.
Claim 2
Dependent Claim
327 words
An electromagnetic device for lifting from the commutator of an electric machine brushes which are normally applied to the commutator by brush-loading spring means, the device comprising lifting means including a brush-lifter ring operable by rotation about the axis of the commutator to withdraw the brushes from contact with the commutator against the action of said brushloading spring means, lifting spring means associated with said brush-lifter ring and urging said ring in the direction of such brush-lifting operation with a torque sufficient to move the ring from an inoperative position allowing the brushes to engage the commutator to an operative position in which the brushes are lifted off the commutator, and a rotary solenoid operative when energized to return said brush-lifter ring from its operative position to its inoperative position against the action of said lifting-spring means, said rotary solenoid including an annular yoke and a magnetizing coil, both coaxial with the commutator, and an armature member coaxially rotatable relative to the yoke and mechanically connected to said brush-lifter ring, said yoke having circumferentially spaced pole pieces projecting at one side of the coil to form, when the coil is energized, magnetic poles of one polarity, and said armature member including armature elements spaced circumferentially for respective cooperation with said pole pieces and each having two surface portions extending approximately in the direction of movement of the element about the common axis of the commutator and armature member and facing respectively one of said pole pieces and a surface portion of said yoke at the opposite side of the coil, the mutually facing surface portions of said armature element and pole piece being inclined relative to the direction of their relative movements over at least part of their length in such manner as to cause the effective airgap between the armature element and yoke to decrease as the armature member moves, when the coil is energized, the brush-lifting ring from its inoperative position towards its operative position.
Claim 3
Dependent Claim
184 words
Device as claimed in claim 1, wherein the yoke has a set of outer pole pieces spaced circumferentially, a set of inner pole pieces similarly spaced and arranged to face the outer pole pieces across a radial gap, with the coil arranged to produce a magnetic field in which the inner and outer pole pieces are respectively magnetized with opposite polarity, the armature member having a set of magnetizable armature pole pieces which are angularly spaced similarly to the pole pieces of the yoke and are so arranged so as to be able, by rotation of the armature member, to enter each gap between an inner aNd outer pole piece of the yoke, leaving residual radial gaps at their inner and outer surfaces, at least one of these residual gaps varying in radial width from a maximum operative when the armature pole piece is substantially withdrawn rotationally from the gap between two coordinated pole pieces of the yoke, to a minimum operative when the armature pole piece has entered the gap between the two coordinated pole pieces of the yoke to the maximum extent.
Claim 4
Dependent Claim
66 words
A device as claimed in claim 1 for use with an engine starter, wherein the solenoid is arranged to be energized automatically prior to the energization of the circuit including the commutator brushes and the starter-field winding in series with the starter armature the solenoid-energizing circuit including a switch opening the circuit when and as long as the speed of the machine exceeds a predetermined value.
References Cited (Backward Citations)
US2295289A
Cited
US2446297A
Cited
US2472018A
Cited
US2475276A
Cited
US2780949A
Cited
US3278777A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |