Communications: electrical – Condition responsive indicating system – Specific condition
Reexamination Certificate
2001-03-16
2002-10-01
Lefkowitz, Edward (Department: 2632)
Communications: electrical
Condition responsive indicating system
Specific condition
C340S635000, C340S654000, C340S664000
Reexamination Certificate
active
06459381
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to apparatus for detection of the proper function of an electric fence and/or a fence charger intended to maintain charge on the fence. More particularly, the invention relates to a compact and durable sensing device which can be readily mounted onto or near an electric fence for detecting proper operation of the fence and of a charging device intended to maintain a nominally steady or periodically applied charge on the fence.
2. Description of the Prior Art
The imposition of an electrical charge on fencing intended to maintain livestock within a specified area has become well known as an alternative or addition to the fencing of livestock or the like by means of conventional fencing intended to retain such stock by virtue of the strength of the fencing rather than by an electrical charge which causes the stock to avoid the fencing. Electric fencing is charged to an appropriate voltage by means of fence charging apparatus which typically apply either continuous or pulsed current to at least one electrical conductor comprising the fencing. Examples of presently available electric fence chargers include the random pulse charging apparatus of Phillips et al which is disclosed in U.S. Pat. No. 4,316,232. McKissack, in U.S. Pat. No. 4,859,869, discloses the use of transformers for applying a continuous charge for energization of an electric fence. Standing, in U.S. Pat. Nos. 4,394,583 and 4,691,084, describe electrical fence chargers as does Shaw et al in U.S. Pat. No. 5,381,298.
While electric fence and fence charger combinations usually provide satisfactory operation, certain circumstances can occur whereby a fence can lose its electrical charge either by failure of the fence charger or by damage to the fence itself such as by cutting of the fence or other circumstance which causes an open circuit or “short” condition. While fence charging apparatus may employ visual or audible signals on the apparatus itself to indicate failure or incipient failure of the fence charger, it is not possible to determine these conditions unless personnel are deployed in the area of the fence chargers per se in order to detect such indications. Accordingly, a need has been felt in the art to provide a simple and inexpensive means by which an observer at essentially any location along an electric fence can be informed of the operational state of the electric fence so that a determination can be made in the event of an indicated failure as to whether a failure of the fence charger exists or whether conductive elements of the electric fence have been breached such as by cutting or other separation thus causing an open or short circuit. The art has previously provided monitoring and alarm systems used in association with electric fences and fence chargers. Begg, in U.S. Pat. No. 4,523,187, provides one such alarm while Pope et al, in U.S. Pat. No. 4,220,949, provides a fence monitor as does Hamm in U.S. Pat. No. 5,550,530. McCutchan et al, in U.S. Pat. No. 4,297,633, provides remote devices on electric fence sections whereby the devices transmit signals to a central control location. Although the art has provided monitoring and alarm systems such as are represented by the United States patents cited herein, the art continues to feel the need for a compact and inexpensive device which can be placed on a conductive element of an electric fence and which provides a signal, particularly a visual signal in the form of a flashing light, in the event of the inability of a fence charger to maintain an electric charge on the fence or the lack of a charge on any portion of the fence such as can occur due to heavy vegetation loading that portion of the fence or a separation of at least one of the electrical conductors of the fence such as by cutting or any separation of electrical conductors or collapse of any portion of the fence causing an open or short circuit. The present invention provides in a compact, inexpensive and exceptionally durable apparatus circuitry for sensing the operational state of an electric fence and/or the electric fence charger intended to maintain an electric charge on the fence and in the several embodiments thereof finds compatibility with known fence chargers whether pulsed or continuous.
SUMMARY OF THE INVENTION
The invention provides a compact, inexpensive and exceptionally durable device which can be simply attached at a multiplicity of locations on or in close proximity to a conductive portion of an electric fence with contact thus being provided between the fence and circuitry internal of the device, any desired number of the present devices being usable without drawing down voltage. The device of the invention in its several embodiments includes a self-contained power source such as batteries of appropriate size and voltage, a circuit board carrying circuitry elements, a source of illumination disposed within the device and a shock-resistant “plastic” lens which forms at least a part of a housing within which components of the device are disposed and interrelated for appropriate function. The devices of the invention may be disposed at locations sufficiently close to electrified wire fence conductors such that electric field is sensed even though the devices of the invention do not actually contact electrically charged wire conductors.
Circuitry suitable to an appropriate operation of the invention can take a variety of forms according to the invention with that part of the circuitry causing communication with the electric fence and/or with the fence charger being a clip or other mounting arrangement which simply and readily fits over an electrical conductor of the electric fence at any location of the fence or an electric potential sensing means such as an electrically conductive element housed within the device and positioned sufficiently close to an electrical conductor of the fence, the clip, other mounting arrangement or electric potential sensing means being directly connected to circuitry internal of the device, which circuitry causes operation of the device to provide an appropriate visual signal in the event of the failure of the fence to exhibit an appropriate charge or the failure of the fence charger to appropriately charge the fence. The circuitry can also sense when voltage drops below a predetermined value and provides a signal indication of such a voltage drop. A particularly useful circuit defined according to the invention includes an integrated circuit as a part of the circuitry providing control, an output from the integrated circuit causing a transistor to oscillate, oscillation of the transistor controlling a light source carried by the device. It should be understood that the light source is preferably carried within the device in order to prevent damage to the light source. In this preferred circuit, the integrated circuit functions essentially as a timer and further provides means for adopting other functions to the circuitry as desired. For example, self-test functions or the like can be incorporated into the preferred circuitry due to the presence within the circuitry of the integrated circuit comprising the timer function. In a similar vein, auxiliary subsystems can be connected into the circuitry through the integrated circuit to provide other functions without any real modification of the original circuit.
The invention further contemplates provision of a control and/or timing function by means of the operation of discrete circuit elements including at least one resistor and at least one transistor which function to control the oscillation of a transistor and thus control of the light source. It is to be understood that the light source in the several embodiments of the invention can take several forms including low voltage DC lamps of the incandescent types as well as light emitting diodes of various description, it being desirable to utilize light emitting diodes having the capability of flashing operation.
In the several embodiments of the present circuitry, it
Carson Anthony R.
Lam Kiet Q.
Darnell Kenneth E.
Goins Davetta W.
Lefkowitz Edward
Tru-Test Limited
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