Patent US3742047A successfully refreshed from Google Patents.
US4246504A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric motors
Assignee: Horstmann Clifford Magnetics Ltd
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Filing: 1978-06-21
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Granted: 1981-01-20
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Expires: 1998-06-21
Abstract
Abstract An alternating current electric motor comprises a stator and a substantially flat armature of magnetic material. The armature is adapted to move relative to the stator and has a plurality of sections which are mutually spaced in the direction of intended movement of the armature. The stator has a plurality of poles having coplanar polefaces spaced apart in the direction of travel of the armature and all of the polefaces are spaced from and face one side only of the armature. At least one winding is wound upon the stator and is arranged so that upon energisation of the winding by an alternating current all of the polefaces are of like polarity and the relative flux density of adjacent ones of the polefaces is caused to alternate without polarity change about a mean value. The alternation of relative flux density of the adjacent polefaces induces movement of the armature relative to the stator.
Inventors
- 👤 Cecil F. Clifford
- 👤 Laurence H. Finlayson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:18
CPC Classifications
H; H02; H02K; H02K21/00; H02K21/38; H02K21/44
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
138 words
An alternating current electric motor comprising a stator and a substantially flat armature of magnetic material adapted to move relative to the stator and having a plurality of sections mutually spaced in the direction of intended movement of the armature the stator having a plurality of poles having coplanar polefaces spaced apart in the direction of travel of the armature all of which polefaces are spaced from and face one side only of the armature, and at least one winding wound upon the stator and so arranged that on energisation of the winding by an alternating current all of the polefaces are of like polarity and the relative flux density of adjacent ones of the polefaces is caused to alternate without polarity change about a mean value, thereby to induce movement of the armature relative to the stator.
Claim 2
Dependent Claim
138 words
An alternating current electric motor comprising a stator and a substantially flat armature of magnetic material adapted to move relative to the stator and having a plurality of sections mutually spaced in the direction of intended movement of the armature the stator having a plurality of poles having coplanar polefaces spaced apart in the direction of travel of the armature all of which polefaces are spaced from and face one side only of the armature, and at least one winding wound upon the stator and so arranged that on energisation of the winding by an alternating current all of the polefaces are of like polarity and the relative flux density of adjacent ones of the polefaces is caused to alternate without polarity change about a mean value, thereby to induce movement of the armature relative to the stator.
Claim 3
Dependent Claim
166 words
An alternating current electric motor comprising a stator and a substantially flat armature of magnetic material adapted to move relative to the stator and having a plurality of sections mutually spaced in the direction of intended movement of the armature, the stator having a plurality of poles having coplanar polefaces spaced apart in the direction of travel of the armature all of which polefaces are spaced from and face one side only of the armature the poles being situated in adjacent pairs which have their faces offset to opposite sides of an axis extending in the direction of intended movement of the armature and at least one winding wound upon the stator and so arranged that on energisation of the winding by an alternating current all of the polefaces are of like polarity and the relative flux density of adjacent ones of the polefaces is caused to alternate without polarity change about a mean value, thereby to induce movement of the armature relative to the stator.
Claim 4
Dependent Claim
166 words
An alternating current electric motor comprising a stator and a substantially flat armature of magnetic material adapted to move relative to the stator and having a plurality of sections mutually spaced in the direction of intended movement of the armature, the stator having a plurality of poles having coplanar polefaces spaced apart in the direction of travel of the armature all of which polefaces are spaced from and face one side only of the armature the poles being situated in adjacent pairs which have their faces offset to opposite sides of an axis extending in the direction of intended movement of the armature and at least one winding wound upon the stator and so arranged that on energisation of the winding by an alternating current all of the polefaces are of like polarity and the relative flux density of adjacent ones of the polefaces is caused to alternate without polarity change about a mean value, thereby to induce movement of the armature relative to the stator.
Claim 5
Dependent Claim
29 words
An electric motor in accordance with claim 1 or 2, wherein said poles are formed by permanent magnets and like polarity faces of the permanent magnets form said polefaces.
Claim 6
Dependent Claim
31 words
An electric motor in accordance with claim 1 or 2, wherein the stator is adapted to be biased by a d.c. current in order to provide said polefaces of like polarity.
Claim 7
Dependent Claim
40 words
An electric motor in accordance with claim 1 or 2, wherein the polefaces are arranged to provide a flux density bias of said like polarity of magnitude substantially equal to the amplitude of alternating flux produced by said alternating current.
Claim 8
Dependent Claim
41 words
An electric motor in accordance with claim 1 or 2, wherein the armature is in the form of a flat vane and is spaced from the stator by an air gap of width substantially equal to the thickness of the armature.
Claim 9
Dependent Claim
24 words
A motor in accordance with claim 2, wherein said pole pairs are also relatively displaced in the direction of intended movement of the armature.
Claim 10
Dependent Claim
31 words
An electric motor in accordance with claim 1, 2 or 7, wherein the stator poles are coplanar and lie in a plane perpendicular to the axis of rotation of the rotor.
Claim 11
Dependent Claim
66 words
A rotary electric motor in accordance with claim 7, wherein the armature comprises a rotor in which said sections comprise parts of a segment alternate ones of which are defined by outer and intermediate pitch circle diameters and intermediate and inner pitch circle diameters respectively and said polefaces are aligned alternately between outer and intermediate pitch circle diameters and intermediate and inner pitch circle diameters respectively.
Claim 12
Dependent Claim
69 words
A rotary electric motor in accordance with claim 2, wherein the armature comprises a rotor in which said sections each comprise a segment of magnetic material which extends radially of the axis of rotation of the rotor and the stator has stator poles arranged around the axis of rotation of the rotor so that upon rotation thereof each rotor segment intersects the magnetic flux of each poleface in turn.
Claim 13
Dependent Claim
72 words
An electric motor in accordance with claim 10 or 9 wherein the stator comprises a circular core, an annular coaxial groove is provided in the core so as to separate an annular outer core portion coaxial with the axis of rotation of the rotor and an inner core portion concentric with the outer element, the polefaces being provided on said core portions and the or each winding being located in the groove.
Claim 14
Dependent Claim
30 words
An electric motor in accordance with claim 10 or 9 wherein the extremities of the segments of the rotor are bent to reduce the air gap between rotor and stator.
Claim 15
Dependent Claim
24 words
An electric motor in accordance with claim 10 or 9 wherein one or more circumferentially extending slots are provided in extremities of the segments.
Claim 16
Dependent Claim
31 words
An electric motor in accordance with claim 10 or 9 wherein the stator poles comprise permanent magnet segments arranged at equal angular intervals around the axis of rotation of the rotor.
Claim 17
Dependent Claim
17 words
An electric motor in accordance with claim 12, wherein the stator pole segments have equal angular width.
Claim 18
Dependent Claim
25 words
An electric motor in accordance with claim 15, wherein the angular width of the rotor sections is the same as that of the stator polefaces.
Claim 19
Dependent Claim
40 words
An electric motor in accordance with claim 16, wherein the number of rotor sections is one half the number of stator polefaces, the rotor sections being spaced apart by spaces of the same angular width as the rotor segments themselves.
Claim 20
Dependent Claim
46 words
An electric motor in accordance with claim 11, wherein the stator poles are superimposed on said inner and outer core portions so that the poles carried by the inner core portion alternate with those carried by the outer core portion around the axis of the core.
References Cited (Backward Citations)
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GB1023930A
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GB1124571A
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GB1084479A
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GB1343372A
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US3999107A
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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) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |