Patent US3663851A successfully refreshed from Google Patents.
US3663851A
Expired / Lapsed
US
⏱️ 0.0 years remaining
D.c. motor
Assignee: ELECTRO CRAFT CORP
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Filing: 1970-09-21
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Granted: 1972-05-16
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Expires: 1990-09-21
Abstract
Abstract A d.c. motor having large, semicylindrical, chamfered pole pieces of soft magnetic material for focusing the magnetic flux of two permanent magnets onto the armature of the motor to provide an increased flux density. the armature has skewed slots and the edges of the pole pieces are skewed in opposition to the skewed slots to achieve the effect of a complete slot pitch skew in a short armature stack without having the loss of wire space normally associated with the severe skew angle previously utilized. The motor is mounted in an improved housing that has a removable brush cap attached to a retaining ring which is rotatable within a slot in the housing transverse to the axis of armature rotation to permit rotary adjustment of the brush cap.
Inventors
- 👤 Erland K Persson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 22:41
CPC Classifications
H; H02; H02K; H02K5/00; H02K5/04; H02K5/15; H02K23/00; H02K23/02; H02K23/04; H02K5/14; H02K5/143; H02K5/148
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
152 words
A rotary electromagnetic device comprising a housing member, a slotted armature journaled for rotation within said housing member, the slots of said armature being skewed less than one slot pitch with respect to the rotary axis thereof, said armature having a small axial length to diameter ratio, a magnet having at least two opposing pole pieces mounted within said housing member adjacent to said armature for applying a magnetic field thereto, the axially extending edges of said pole pieces being similarly skewed in complementary opposition to the skewed slots of said armature for minimizing the slot lock effect and thereby reduce the skew angle required for the armature slots to less than one slot pitch, so as to increase the amount of space available on the armature for windings, an electrical winding attached to said armature for Rotation therewith, and means for coupling electrical energy between said winding and said housing member.
Claim 2
Dependent Claim
152 words
A rotary electromagnetic device comprising a housing member, a slotted armature journaled for rotation within said housing member, the slots of said armature being skewed less than one slot pitch with respect to the rotary axis thereof, said armature having a small axial length to diameter ratio, a magnet having at least two opposing pole pieces mounted within said housing member adjacent to said armature for applying a magnetic field thereto, the axially extending edges of said pole pieces being similarly skewed in complementary opposition to the skewed slots of said armature for minimizing the slot lock effect and thereby reduce the skew angle required for the armature slots to less than one slot pitch, so as to increase the amount of space available on the armature for windings, an electrical winding attached to said armature for Rotation therewith, and means for coupling electrical energy between said winding and said housing member.
Claim 3
Dependent Claim
67 words
The device of claim 1 in which said magnet comprises two semicylindrical permanent magnets made of ceramic ferro-magnetic material, said magnets being radially magnetized and mounted in opposing relationship within said housing member around said armature and at least two semicylindrical metallic pole pieces attached to the inner surface of said permanent magnets in opposing relationship for directing magnetic flux from said permanent magnets to said armature.
Claim 4
Dependent Claim
17 words
The device of claim 2 in which the sides of said metallic pole pieces are chamfered inwardly.
Claim 5
Dependent Claim
114 words
A rotary electromagnetic device comprising a housing member, an armature journaled for rotation within said housing member, an electrical winding and a commutator attached to said armature for rotation therewith, means coupling said winding to said commutator, means for applying a magnetic field to said armature for interaction with said electrical winding, a slot formed in the inner surface of said housing member transverse to the axis of rotation of said armature, a retaining ring rotatably mounted within said slot, a brush assembly for electrically engaging said commutator, and means for attaching said brush assembly to said retaining ring whereby said brush assembly can be rotated with respect to said housing for alignment purposes.
Claim 6
Dependent Claim
114 words
A rotary electromagnetic device comprising a housing member, an armature journaled for rotation within said housing member, an electrical winding and a commutator attached to said armature for rotation therewith, means coupling said winding to said commutator, means for applying a magnetic field to said armature for interaction with said electrical winding, a slot formed in the inner surface of said housing member transverse to the axis of rotation of said armature, a retaining ring rotatably mounted within said slot, a brush assembly for electrically engaging said commutator, and means for attaching said brush assembly to said retaining ring whereby said brush assembly can be rotated with respect to said housing for alignment purposes.
Claim 7
Dependent Claim
107 words
The device of claim 4 in which said armature is slotted, the slots thereof being skewed with respect to the axis of rotation thereof, and in which said means for applying a magnetic field to said armature comprises a permanent magnet having at least two opposing pole pieces mounted within said housing member adjacent to said armature for applying a magnetic field thereto, the edges of said pole pieces being skewed in opposition to the skewed slots of said armature for minimizing the slot lock effect and reducing the angle required for the armature slots, thereby increasing the amount of space available on the armature for windings.
Claim 8
Dependent Claim
68 words
The device of claim 5 in which said permanent magnet comprises two semicylindrical permanent magnets made of ceramic ferro-magnetic material, said magnets being radially magnetized and mounted in opposing relationship within said housing member around said armature, and at least two semicircular metallic pole pieces attached to the inner surface of said permanent magnets in opposing relationship for directing magnetic flux from said permanent magnets to said armature.
Claim 9
Dependent Claim
127 words
A magnetic focusing structure for use in combination with a rotary electromagnetic device including a housing member and an armature journaled for rotation within said housing member, said magnetic focusing structure comprising two semicylindrical permanent magnets mounted in opposing relationship within said housing member around said armature and two semicylindrical metallic pole pieces attached to the inner surface of said permanent magnets in opposing relationship for focusing the magnetic flux of said permanent magnets onto said armature, said magnets being relatively long in their axial dimension with respect to said armature, and the axial ends of said pole pieces being chamfered to focus the magnetic flux thereof into a smaller area, thereby increasing the flux density at the surface of the pole piece adjacent to said armature.
Claim 10
Dependent Claim
127 words
A magnetic focusing structure for use in combination with a rotary electromagnetic device including a housing member and an armature journaled for rotation within said housing member, said magnetic focusing structure comprising two semicylindrical permanent magnets mounted in opposing relationship within said housing member around said armature and two semicylindrical metallic pole pieces attached to the inner surface of said permanent magnets in opposing relationship for focusing the magnetic flux of said permanent magnets onto said armature, said magnets being relatively long in their axial dimension with respect to said armature, and the axial ends of said pole pieces being chamfered to focus the magnetic flux thereof into a smaller area, thereby increasing the flux density at the surface of the pole piece adjacent to said armature.
Claim 11
Dependent Claim
22 words
The magnetic focusing structure of claim 7 in which said permanent magnets are made of ceramic ferro-magnetic material and are radially magnetized.
Claim 12
Dependent Claim
59 words
The magnetic focusing structure of claim 7 in which said armature contains skewed slots of less than one pole pitch and in which the ends of said pole pieces are skewed in complementary opposition to the skewed slots in the armature for minimizing the slot lock effect and increasing the amount of space available on the armature for windings.
Claim 13
Dependent Claim
23 words
The magnetic focusing structure of claim 7 wherein said semicylindrical magnets and pole pieces substantially surround the entire surfacE area of said armature.
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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) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |