Patent US2842459A successfully refreshed from Google Patents.
US4335568A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filament-type vegetation trimmer with automatic line sensor
Assignee: Max Langenstein Feld und Gartengeraete GmbH and Co
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Filing: 1981-07-30
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Granted: 1982-06-22
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Expires: 2001-07-30
Abstract
Abstract A filament-type vegetation trimmer has an electric motor, a head rotatable by the motor, and a supply of a filament in the head, with the filament extending from the head, whereby on rotation of the head by the motor the extending filament section can cut vegetation. The trimmer further comprises a circuit for detecting the current consumption of the motor and for generating an actual-value output corresponding thereto, an actual-value generator for generating a set-point output corresponding to the current consumption of the motor when the filament is extending from the head by less than a predetermined distance, and a comparator for comparing these outputs and generating a signal when the actual-value output is less than the set-point output.
Inventors
- 👤 Max Langenstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 10:01
CPC Classifications
A; A01; A01D; A01D34/00; A01D34/01; A01D34/412; A01D34/416; Y; Y10; Y10S; Y10S56/00; Y10S56/15
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
131 words
A filament-type vegetation trimmer comprising: an electric motor; a head rotatable by said motor; a supply of a filament in said head, with said filament extending from said head, whereby on rotation of said head by said motor the extending filament section can cut vegetation; means for detecting the current consumption of said motor and for generating an actual-value output corresponding thereto; means for generating a set-point output corresponding to the current consumption of said motor when said filament is extending from said head by less than a predetermined distance; and means for comparing said outputs and generating a signal when said actual-value output is less than said set-point output, and means in said head for responding to said signal and releasing more of said filament when said signal is generated.
Claim 2
Dependent Claim
131 words
A filament-type vegetation trimmer comprising: an electric motor; a head rotatable by said motor; a supply of a filament in said head, with said filament extending from said head, whereby on rotation of said head by said motor the extending filament section can cut vegetation; means for detecting the current consumption of said motor and for generating an actual-value output corresponding thereto; means for generating a set-point output corresponding to the current consumption of said motor when said filament is extending from said head by less than a predetermined distance; and means for comparing said outputs and generating a signal when said actual-value output is less than said set-point output, and means in said head for responding to said signal and releasing more of said filament when said signal is generated.
Claim 3
Dependent Claim
31 words
The trimmer defined in claim 1 wherein said means for detecting includes a resistor in series with said motor and a diode and filter connected between said resistor and said motor.
Claim 4
Dependent Claim
30 words
The trimmer defined in claim 2 wherein said means for comparing and generating includes a visual indicator and means for operating same when said actual-value output exceeds said set-point output.
Claim 5
Dependent Claim
13 words
The trimmer defined in claim 3 wherein said indicator is a light-emitting diode.
Claim 6
Dependent Claim
29 words
The trimmer defined in claim 3 whereif said indicator is a pair of alternately energized light-emitting diodes, one of which is red and the other of which is green.
Claim 7
Dependent Claim
18 words
The trimmer defined in claim 1 wherein said motor is an alternating-current motor normally powered by line voltage.
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) | 1985-06-21 | 1985-12-21 | 1986-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-21 | 1989-12-21 | 1990-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-21 | 1993-12-21 | 1994-06-22 | $7700.00 | Window Closed / Lapsed |