US3868545A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable frequency electric fence charging circuit
Assignee: STA TITE CORP
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Filing: 1973-09-10
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Granted: 1975-02-25
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Expires: 1993-09-10
Abstract
Abstract A variable frequency electric fence charging circuit for supplying charge pulses to a conductive fence wire at selected frequencies adapted to the particular livestock to be restrained comprises a firing circuit utilizing a silicon controlled rectifier connected to the primary winding of a step-up transformer and connectable to an alternating current source to deliver a charging pulse through the transformer to a fence wire when the silicon controlled rectifier is made conducting by a triggering circuit. The triggering circuit includes an oscillator with its output connected to the gate of the silicon controlled rectifier to selectively, periodically open the gate to permit current flow from the alternating current source to the primary winding of the transformer, inducing a high voltage in the secondary winding which is applied to the fence wire. The time constant of the oscillator may be varied by the operator to produce two distinct oscillator frequencies, permitting use of the frequency best adapted to the livestock to be restrained. The triggering circuit energizes the oscillator in synchronization with the alternating current source to assure that the oscillator opens the gate only when the alternating current source nears a peak voltage magnitude to assure high voltage being applied to the transformer primary. The charging circuit is protected from lightning or other high voltage transients reaching it from either the fence wire or the alternating current source.
Inventors
- 👤 Thomas E Caron
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 08:20
CPC Classifications
H; H05; H05C; H05C1/00; H05C1/04
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
285 words
A variable frequency electric fence charging circuit for use with an alternating current source and a conductive fence wire for charging the fence wire to restrict movement of various types of livestock, comprising: a firing circuit including input terminals, a silicon controlled rectifier with a gate, and a step-up transformer with primary and secondary windings, said silicon controlled rectifier electrically connected in series with said primary winding and connectable across the alternating current source, said secondary winding defining the output of said firing circuit and being electrically connectable between the fence wire and ground; a triggering circuit, including an oscillator, said oscillator having input and output terminals and being provided with means for selectively establishing a plurality of distinct predetermined output frequencies and said frequency establishing means being substantially unaffected by impedance variations in the fence wire caused by livestock contact with the wire, the output terminals of said oscillator electrically connected to said gate of said silicon controlled rectifier to selectively bias said gate to an open condition, permitting current flow from the alternating current source to said primary winding, thereby inducing stepped up voltage in said secondary winding and charging the fence wire; and said triggering circuit further including a diode and capacitor, said diode energizable from the alternating current source, and connected in parallel with said capacitor and in series to the input terminal of said oscillator to energize said oscillator in synchronization with the alternating current source such that said oscillator develops and delivers periodic output pulses biasing said gate of said silicon controlled rectifier to an open condition as the alternating current source nears a peak voltage magnitude to thereby apply the voltage to said primary winding of said transformer.
Claim 2
Dependent Claim
285 words
A variable frequency electric fence charging circuit for use with an alternating current source and a conductive fence wire for charging the fence wire to restrict movement of various types of livestock, comprising: a firing circuit including input terminals, a silicon controlled rectifier with a gate, and a step-up transformer with primary and secondary windings, said silicon controlled rectifier electrically connected in series with said primary winding and connectable across the alternating current source, said secondary winding defining the output of said firing circuit and being electrically connectable between the fence wire and ground; a triggering circuit, including an oscillator, said oscillator having input and output terminals and being provided with means for selectively establishing a plurality of distinct predetermined output frequencies and said frequency establishing means being substantially unaffected by impedance variations in the fence wire caused by livestock contact with the wire, the output terminals of said oscillator electrically connected to said gate of said silicon controlled rectifier to selectively bias said gate to an open condition, permitting current flow from the alternating current source to said primary winding, thereby inducing stepped up voltage in said secondary winding and charging the fence wire; and said triggering circuit further including a diode and capacitor, said diode energizable from the alternating current source, and connected in parallel with said capacitor and in series to the input terminal of said oscillator to energize said oscillator in synchronization with the alternating current source such that said oscillator develops and delivers periodic output pulses biasing said gate of said silicon controlled rectifier to an open condition as the alternating current source nears a peak voltage magnitude to thereby apply the voltage to said primary winding of said transformer.
Claim 3
Dependent Claim
64 words
The electrical charge circuit of claim 1 and further including a varistor electrically connected in said firing circuit, said varistor constructed to provide a shunt across the alternating current source in response to power line surges from the alternating current source which are in excess of voltage levels capable of damaging the charging circuit, thereby protecting the charging circuit from such power line surges.
Claim 4
Dependent Claim
65 words
The electrical charging circuit of claim 1 wherein said triggering circuit includes a combined triggering and monitoring device providing a closed circuit across said device in response to the voltage across said device reaching a predetermined value and producing a visual indication when said device is conducting, permitting an operator to visually determine that said triggering circuit is biasing said gate to an open condition.
Claim 5
Dependent Claim
56 words
The variable frequency electric fence charging circuit of claim 1 wherein said oscillator further includes a manually actuated switch and first and second impedance elements, said switch electrically connected to said first and second impedance defining elements to alternately vary the impedance of said oscillator and thereby create two predetermined, distinct output frequencies for said oscillator.
Claim 6
Dependent Claim
49 words
The variable frequency electric fence charging circuit of claim 4 wherein said switch is a single-pole double-throw switch and electrically connected to said first and second impedance elements to permit alternate manual introduction of one of said impedance elements into said oscillator to selectively vary the oscillator output frequency.
Claim 7
Dependent Claim
199 words
A variable frequency electric fence charging circuit for use with a current source and a conductive fence wire for charging the fence wire to restrict movement of various types of livestock, comprising: a firing circuit including input terminals, a silicon controlled rectifier with a gate, and a step-up transformer with primary and secondary windings, said silicon controlled rectifier electrically connected in sEries with said primary winding and connectable across the current source, said secondary winding defining the output of said firing circuit and being electrically connectable between the fence wire and ground; a triggering circuit, including an oscillator energizable by the alternating current source, said oscillator having input and output terminals and being provided with means for selectively establishing a plurality of distinct predetermined output frequencies and said frequency establishing means being substantially unaffected by impedance variations in the fence wire caused by livestock contact with the wire, the output terminals of said oscillator electrically connected to said gate of said silicon controlled rectifier to selectively bias said gate to an open condition, permitting current flow from the alternating current source to said primary winding, thereby inducing stepped up voltage in said secondary winding and charging the fence wire.
Claim 8
Dependent Claim
199 words
A variable frequency electric fence charging circuit for use with a current source and a conductive fence wire for charging the fence wire to restrict movement of various types of livestock, comprising: a firing circuit including input terminals, a silicon controlled rectifier with a gate, and a step-up transformer with primary and secondary windings, said silicon controlled rectifier electrically connected in sEries with said primary winding and connectable across the current source, said secondary winding defining the output of said firing circuit and being electrically connectable between the fence wire and ground; a triggering circuit, including an oscillator energizable by the alternating current source, said oscillator having input and output terminals and being provided with means for selectively establishing a plurality of distinct predetermined output frequencies and said frequency establishing means being substantially unaffected by impedance variations in the fence wire caused by livestock contact with the wire, the output terminals of said oscillator electrically connected to said gate of said silicon controlled rectifier to selectively bias said gate to an open condition, permitting current flow from the alternating current source to said primary winding, thereby inducing stepped up voltage in said secondary winding and charging the fence wire.
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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) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |