Patent US3841305A successfully refreshed from Google Patents.
US3841305A
Expired / Lapsed
US
⏱️ 0.0 years remaining
External inductive neural stimulator system
Assignee: Iowa State University Research Foundation Inc
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Filing: 1972-10-25
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Granted: 1974-10-15
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Expires: 1992-10-25
Abstract
Abstract A system for external stimulation of a nerve includes a coil of wire with a flux-concentrating core in the lumen of the coil. The core preferably has a T-shape, with the base of the T extending through the lumen of the coil providing the area of stimulation. The coil is pulsed by a discharging capacitor and circuitry is disclosed for charging the capacitor and generating discharge pulses of alternate polarity.
Inventors
- 👤 R Hallgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:33
CPC Classifications
A; A61; A61N; A61N1/00; A61N1/40
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
A system for external tetanic stimulation of nerves comprising: a coil of conductive wire wound into a generally flat, circular shape providing a central lumen; magnetic core means extending through said lumen for concentrating the flux lines in the core extending through the lumen and providing an application surface for contacting an external body surface to apply electromagnetic energy, said application surface extending transverse of said core means to transversely cut the flux lines concentrated therein; and circuit means including a source of electrical energy, a discharge capacitor, first control switch means for selectively coupling said capacitor to said coil, timing circuit means for periodically triggering said first switch means to discharge said capacitor means through said coil, and detector means responsive to the charge on said capacitor and including second control switch means for charging said capacitor at a time when said first switch means is not discharging the same and for electrically isolating said capacitor from said source means when said first switch means is discharging said capacitor.
Claim 2
Independent Claim
170 words
A system for external tetanic stimulation of nerves comprising: a coil of conductive wire wound into a generally flat, circular shape providing a central lumen; magnetic core means extending through said lumen for concentrating the flux lines in the core extending through the lumen and providing an application surface for contacting an external body surface to apply electromagnetic energy, said application surface extending transverse of said core means to transversely cut the flux lines concentrated therein; and circuit means including a source of electrical energy, a discharge capacitor, first control switch means for selectively coupling said capacitor to said coil, timing circuit means for periodically triggering said first switch means to discharge said capacitor means through said coil, and detector means responsive to the charge on said capacitor and including second control switch means for charging said capacitor at a time when said first switch means is not discharging the same and for electrically isolating said capacitor from said source means when said first switch means is discharging said capacitor.
Claim 3
Dependent Claim
61 words
The system of claim 1 wherein said core means comprises a plurality of T-shaped laminations stacked together and providing a base and a cross bar, the bases of said T-plates extending through the lumen of said coil, the collective bottoms of said legs of said T-plates providing said application surface extending perpendicular to the axis of the base of said T-plates.
Claim 4
Dependent Claim
154 words
In a system for the electromagnetic stimulation of nerves, the combination comprising a conductive coil of wire providing a central lumen; core means extending through said lumen for concentrating the magnetic flux generated by said coil; a discharge capacitor; first switch means for selectively connecting said capacitor to said coil; a source of periodically alternating voltage; second switch means for selectively connecting said source to charge said capacitor; polarity detector circuit means responsive to the polarity of voltage on said capacitor for selectively energizing said second switch means to charge said capacitor to a peak voltage having the same polarity as the existing voltage on said capacitor; and pulse control circuit means for selectively energizing said first switch means to discharge said capacitor through said coil to generate a stimulating pulse in mutually exclusive time relation with said polarity detector means, whereby said capacitor is isolated from said source when said capacitor is discharged.
Claim 5
Dependent Claim
154 words
In a system for the electromagnetic stimulation of nerves, the combination comprising a conductive coil of wire providing a central lumen; core means extending through said lumen for concentrating the magnetic flux generated by said coil; a discharge capacitor; first switch means for selectively connecting said capacitor to said coil; a source of periodically alternating voltage; second switch means for selectively connecting said source to charge said capacitor; polarity detector circuit means responsive to the polarity of voltage on said capacitor for selectively energizing said second switch means to charge said capacitor to a peak voltage having the same polarity as the existing voltage on said capacitor; and pulse control circuit means for selectively energizing said first switch means to discharge said capacitor through said coil to generate a stimulating pulse in mutually exclusive time relation with said polarity detector means, whereby said capacitor is isolated from said source when said capacitor is discharged.
Claim 6
Dependent Claim
170 words
The system of claim 3 wherein said first switch means includes first and second control switch means connected between said capacitOr and said coil for coupling respectively current of forward and reverse polarity to said coil; and wherein said pulse control circuit means includes logic counter circuit means responsive to said source voltage for generating a control signal every predetermined number of half cycles thereof; monostable circuit means responsive to said control signal for generating an output pulse when said capacitor is isolated from its associated charging voltage; and means for coupling said output pulse of said monostable circuit to said first and second control switch means to cause the same to conduct, said control signal of said logic circuit means occurring approximately at a time when said alternating voltage is experiencing a zero crossover and the discharge current through said coil ringing only in one polarity, thereby leaving a residual voltage on said capacitor of polarity opposite to the original voltage for sensing by said polarity detector circuit means.
Claim 7
Dependent Claim
97 words
The system of claim 3 wherein said second switch means includes third and fourth control switches; and wherein said polarity detector circuit means comprises first and second channel circuit means for generating a charge control signal respectively during alternate half cycles of said source voltage; and means for coupling the output signals of each of said channel circuit means respectively to said third and fourth control switch means, said third and fourth control switch means being connected in circuit between said source and said capacitor for coupling respectively current of forward and reverse polarity to said capacitor.
Claim 8
Dependent Claim
81 words
The system of claim 5 wherein each of said channels of said polarity detector circuit means includes means for generating a unipolar signal, optical isolation means responsive to said unipolar signal for generating a second electrical signal proportional thereto; and circuit means including threshold circuit means coupled to said capacitor for generating an output signal as long as the voltage on said capacitor is above a predetermined value, said output signal occurring exclusive of times immediately adjacent zero crossover voltages thereof.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |