US3602772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective circuit for electrically driven lawn mowers and the like
Assignee: Wolf Geraete GmbH
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Filing: 1969-09-22
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Granted: 1971-08-31
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Expires: 1989-09-22
Abstract
Abstract A protective circuit for lawn mowers etc. comprises a cable with two auxiliary conductors, forming a circuit which when interrupted brings about interruption of the supply of power through the cable.
Inventors
- 👤 Eckhardt Hundhausen
- 👤 Walter Kolb
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:02
CPC Classifications
H; H01; H01B; H01B7/00; H01B7/32; H01B7/328; A; A01; A01D; A01D34/00; A01D34/01; A01D34/412; A01D34/63; A01D34/82; A01D34/828; A01D69/00; A01D69/02; H02; H02H; H02H5/00; H02H5/10; H02H7/00; H02H7/22; H02H7/226; B; B60; B60L; B60L2200/00; B60L2200/40
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
228 words
A protective circuit for use in protecting persons against electric shock from a circuit coupling a source to a load comprising: an elongated cable having input and output ends for releaseable connection with a power source and a load, respectively; said cable having at least first and second axially aligned main conductors; insulation means; said main conductors being imbedded in said insulation means; at least one slender auxiliary conductor imbedded in said insulation means and being positioned intermediate said main conductors and the outer surface of said cable; the diameter of said auxiliary conductor being substantially smaller than the diameters of the main conductors; the ends of said auxiliary conductor being positioned at one end of said cable, whereby said auxiliary conductor forms an elongated conductive loop extending substantially the entire length of said cable; power coupling means having input means coupled across said main conductors and output means coupled across the ends of said auxiliary conductor for energizing said auxiliary conductor when said main conductors are energized; power sensing means connected to said auxiliary conductor; switch means connected to said main conductors being operable between an open and closed position; said power sensing means including means for moving said switch means to the open position when said auxiliary conductor is energized and for moving said switch means to the open position when said auxiliary conductors are deenergized.
Claim 2
Dependent Claim
228 words
A protective circuit for use in protecting persons against electric shock from a circuit coupling a source to a load comprising: an elongated cable having input and output ends for releaseable connection with a power source and a load, respectively; said cable having at least first and second axially aligned main conductors; insulation means; said main conductors being imbedded in said insulation means; at least one slender auxiliary conductor imbedded in said insulation means and being positioned intermediate said main conductors and the outer surface of said cable; the diameter of said auxiliary conductor being substantially smaller than the diameters of the main conductors; the ends of said auxiliary conductor being positioned at one end of said cable, whereby said auxiliary conductor forms an elongated conductive loop extending substantially the entire length of said cable; power coupling means having input means coupled across said main conductors and output means coupled across the ends of said auxiliary conductor for energizing said auxiliary conductor when said main conductors are energized; power sensing means connected to said auxiliary conductor; switch means connected to said main conductors being operable between an open and closed position; said power sensing means including means for moving said switch means to the open position when said auxiliary conductor is energized and for moving said switch means to the open position when said auxiliary conductors are deenergized.
Claim 3
Dependent Claim
38 words
The structure as set forth in claim 1 wherein said power sensing means comprises a relay energized by said auxiliary conductor, said switch means being adapted to be operated by said relay to selectively energize the main conductors.
Claim 4
Dependent Claim
47 words
The structure as set forth in claim 1 wherein said power coupling means compriseS a transformer said output means comprising a secondary winding connected with the auxiliary conductor and the relay; said input means comprising a primary winding of the transformer being connected across said main conductors.
Claim 5
Dependent Claim
42 words
The structure as set forth in claim 1 in which said auxiliary conductor comprises at least first and second axially aligned parallel portions, said parallel portions having an even angular spacing and being connected in series at one end of said cable.
Claim 6
Dependent Claim
48 words
The structure as set forth in claim 1 in which said auxiliary conductor comprises first and second portions each extending the length of said cable; said first and second portions crossing over each other and surrounding said main conductors; said helically wound portions being insulated from one another.
Claim 7
Dependent Claim
36 words
The structure as set forth in claim 4 in which said main conductors further include an axially aligned return conductor serving simultaneously as a ground conductor and as one of said auxiliary conductor axially aligned portions.
Claim 8
Dependent Claim
23 words
The structure as set forth in claim 3 comprising a housing in which the transformer, the relay and the switch means are accommodated.
Claim 9
Dependent Claim
17 words
The structure as set forth in claim 7 comprising a socket which is connected with the housing.
Claim 10
Dependent Claim
31 words
The structure as set forth in claim 7 further comprising a cable connecting piece coupled to said main conductors at one end of said cable for releasable connection with said socket.
Claim 11
Dependent Claim
27 words
The structure as set forth in claim 1 in which the auxiliary conductor is in the form of a textile thread with copper strand twisted around it.
Claim 12
Dependent Claim
31 words
The structure as set forth in claim 10 in which the thread with surrounding copper strand is accommodated as an auxiliary conductor individually or bundled in the insulation of the cable.
Claim 13
Dependent Claim
23 words
The structure as set forth in claim 1 in which the auxiliary conductor is in the form of litz with fine individual wires.
Claim 14
Dependent Claim
37 words
The structure as set forth in claim 3 wherein said transformer is adapted to provide a stepped down voltage in the secondary winding whereby the voltage level in the auxiliary conductor is maintained at a nonlethal value.
Claim 15
Dependent Claim
47 words
The structure as set forth in claim 1 in which said auxiliary conductor is comprised of an axially aligned conductor portion and a helically wound conductor portion surrounding said main conductors; said portions being connected in series at one end of said cable and being electrically insulated.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-08-30 | 1975-03-01 | 1975-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-08-30 | 1979-03-01 | 1979-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-08-30 | 1983-03-01 | 1983-08-31 | $7700.00 | Window Closed / Lapsed |