US3740594A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent-electromagnetic reciprocating device
Assignee: FEMA Corp OF MICHIGAN Inc
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Filing: 1971-08-30
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Granted: 1973-06-19
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Expires: 1991-08-30
Abstract
Abstract The device, configured to have a small width with respect to its length in the direction of armature movement, comprises a long tubular, radially magnetized permanent magnet coaxially surrounding a long length armature to provide a large circumferential area of the armature. The permanent magnet and the armature are closely spaced along their facing lengths to provide a small annular gap therebetween. The large area compensates for the size of the gap and permits placement of an electro-magnetic coil in the gap.
Inventors
- 👤 G Casey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:24
CPC Classifications
H; H01; H01F; H01F7/00; H01F7/06; H01F7/08; H01F7/13; H01F7/16; H01F7/1607; H01F7/1615; H02; H02K; H02K33/00; H02K33/16; H01F7/121; H01F7/122
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
276 words
A magnetic device of symmetrical configuration and operation comprising: an elongated, right cylindrical armature of ferromagnetic material bounded by a pair of ends and a circumferencial surface and having a length sufficient to provide a large area circumference, said armature being rectilinearly translatable along its cylindrical axis, and said armature having output shafts extending axially from the ends; an elongated tubular permanent magnet surrounding said armature and coaxially positioned therewith and magnetized radially with respect to the axis, said permanent magnet having an internal cylindrical surface and an external cylindrical surface, said internal surface being closely spaced from said armature circumferencial surface throughout the large area thereof to provide a thin walled tubular gap means of minimum reluctance between said armature and said permanent magnet and to provide a pair of oppositely directed permanent magnet flux paths; an elongated coil positioned in said gap means and extending substantially throughout the circumferencial length of said armature and energizable to provide a single reversible flux path; a housing of ferromagnetic material secured to the external cylindrical surface at said permanent magnet, said housing including a pair of circular end plates with central opening means for journalled support of said armature output shafts, and said central opening means having bosses extending towards one another in spaced proximity from the ends of said armature to provide a pair of working gap means; whereby said armature is reciprocable upon energization of said electromagnet, the electromagnet flux path re-enforcing one of the oppositely directed permanent magnet flux paths and opposing the other of the oppositely directed permanent magnet flux paths, and said flux paths passing entirely throughout said housing and said armature.
Claim 2
Dependent Claim
276 words
A magnetic device of symmetrical configuration and operation comprising: an elongated, right cylindrical armature of ferromagnetic material bounded by a pair of ends and a circumferencial surface and having a length sufficient to provide a large area circumference, said armature being rectilinearly translatable along its cylindrical axis, and said armature having output shafts extending axially from the ends; an elongated tubular permanent magnet surrounding said armature and coaxially positioned therewith and magnetized radially with respect to the axis, said permanent magnet having an internal cylindrical surface and an external cylindrical surface, said internal surface being closely spaced from said armature circumferencial surface throughout the large area thereof to provide a thin walled tubular gap means of minimum reluctance between said armature and said permanent magnet and to provide a pair of oppositely directed permanent magnet flux paths; an elongated coil positioned in said gap means and extending substantially throughout the circumferencial length of said armature and energizable to provide a single reversible flux path; a housing of ferromagnetic material secured to the external cylindrical surface at said permanent magnet, said housing including a pair of circular end plates with central opening means for journalled support of said armature output shafts, and said central opening means having bosses extending towards one another in spaced proximity from the ends of said armature to provide a pair of working gap means; whereby said armature is reciprocable upon energization of said electromagnet, the electromagnet flux path re-enforcing one of the oppositely directed permanent magnet flux paths and opposing the other of the oppositely directed permanent magnet flux paths, and said flux paths passing entirely throughout said housing and said armature.
Claim 3
Dependent Claim
35 words
A magnetic device as in claim 1 further including a pair of linear springs of equal force magnitude positioned between the respective bosses and armature ends to center said armature upon de-energizatioN of said electromagnet.
Claim 4
Dependent Claim
67 words
A magnetic device as in claim 1 wherein the combination of said permanent magnet, said electro-magnet, and the working gap provides a magnetic force-gap characteristic and further including springs positioned between the respective bosses and armature ends, the magnetic force-gap characteristic being related to the spring force-translation characteristics sufficient to provide specific positions of said armature in response to levels and polarities of energization of said electromagnet.
Claim 5
Dependent Claim
61 words
A magnetic device comprising: an armature of ferromagnetic material; a radially magnetized permanent magnet; and an electromagnetic coil ; said armature, said permanent magnet and said coil all being coaxially mounted, said armature having an outer periphery and said permanent magnet having an inner periphery spaced from said armature outer periphery to provide a gap, said coil mounted in the gap.
Claim 6
Dependent Claim
61 words
A magnetic device comprising: an armature of ferromagnetic material; a radially magnetized permanent magnet; and an electromagnetic coil ; said armature, said permanent magnet and said coil all being coaxially mounted, said armature having an outer periphery and said permanent magnet having an inner periphery spaced from said armature outer periphery to provide a gap, said coil mounted in the gap.
Claim 7
Dependent Claim
57 words
A magnetic device as in claim 4 wherein the axial lengths of said armature, said coil and said permanent magnet are greater than the widths thereof normal to the axis to provide a reduced length of coil wire per turn, thereby minimizing resistance through said coil and resulting in reduced power input necessary for obtaining force output.
Claim 8
Dependent Claim
53 words
A magnetic device as in claim 4 further including a pair of ferromagnetic pole pieces positioned at and spaced from the ends of said armature, said pieces having opening means therein disposed on the axis and said armature having force transmitting means extending through said opening means to the exterior of said device.
Claim 9
Dependent Claim
15 words
A magnetic device as in claim 4 further including bias means coupled to said armature.
Claim 10
Dependent Claim
118 words
A magnetic device comprising: an armature of ferromagnetic material having an outer periphery; a radially magnetized permanent magnet coaxially mounted about said armature and having an inner periphery spaced from said armature outer periphery to provide a gap; an electromagnetic coil coaxially mounted about said armature and mounted in the gap; a pair of ferromagnetic pole pieces positioned at and spaced from the ends of said armature, said pieces having opening means therein disposed on the axis and said armature having force transmitting means extending through said opening means; and a housing of ferromagnetic material surrounding and in contact with said permanent magnet and secured to said pieces to provide, with said armature, a continuous magnetic flux path.
Claim 11
Dependent Claim
118 words
A magnetic device comprising: an armature of ferromagnetic material having an outer periphery; a radially magnetized permanent magnet coaxially mounted about said armature and having an inner periphery spaced from said armature outer periphery to provide a gap; an electromagnetic coil coaxially mounted about said armature and mounted in the gap; a pair of ferromagnetic pole pieces positioned at and spaced from the ends of said armature, said pieces having opening means therein disposed on the axis and said armature having force transmitting means extending through said opening means; and a housing of ferromagnetic material surrounding and in contact with said permanent magnet and secured to said pieces to provide, with said armature, a continuous magnetic flux path.
Claim 12
Dependent Claim
99 words
A magnetic device comprising: an armature of ferromagnetic material having an outer periphery; a radially magnetized permanent magnet coaxially mounted about said armature and having an inner periphery spaced from said armature outer periphery to provide a gap; an electromagnetic coil coaxially mounted about said armature and mounted in the gap; a pair of ferromagnetic pole pieces positioned at and spaced from the ends of said armature, said pieces having opening means therein disposed on the axis and said armature having force transmitting means extending through said opening means; and bias means positioned between said armature and said pieces.
Claim 13
Dependent Claim
99 words
A magnetic device comprising: an armature of ferromagnetic material having an outer periphery; a radially magnetized permanent magnet coaxially mounted about said armature and having an inner periphery spaced from said armature outer periphery to provide a gap; an electromagnetic coil coaxially mounted about said armature and mounted in the gap; a pair of ferromagnetic pole pieces positioned at and spaced from the ends of said armature, said pieces having opening means therein disposed on the axis and said armature having force transmitting means extending through said opening means; and bias means positioned between said armature and said pieces.
Claim 14
Dependent Claim
14 words
A magnetic device as in claim 9 wherein said bias means comprises linear springs.
Claim 15
Dependent Claim
14 words
A magnetic device as in claim 9 wherein said bias means comprises non-linear springs.
References Cited (Backward Citations)
US3022450A
Cited
US3462626A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |