US3384788A - Electric stock fencer - Google Patents

Description

T. E. JOHNSTON ELECTRIC STOCK FENCER Filed July 13, 1964 May 21, 1968 \HHHHH IN VEN TOR. B Eda W570 United States Patent 3,384,788 ELECTRIC STOCK FENCER Thomas E. Johnston, 605 N. Main, Shamrock, Tex. 79079 Filed July 13, 1964, Ser. No. 382,297 3 Claims. (Cl. 307-132) ABSTRACT OF THE DISCLOSURE Electric stock fence charger having an RC circuit including a resistance and a capacitance connected to a current supply, a trigger circuit to discharge the capacitor through a vibrator reed relay, and means to energize a primary winding when the contacts of the vibrator are open and a shorting circuit for the winding.

This invention relates to an improved electric stock fence charger, and more particularly to a transistor relaxation oscillator fence charger having improved simple circuitry for providing reliable and efiicient operating characteristics without providing any criticality in the arrangement or connection of the parts of the circuit charger.

The fence charger of the invention uses many standard and readily available parts. The inductance relays may have a resistance of from 50 to 400 ohms, and a vibrator can be used that is readily found in many automobile radio sets. The power or output transistor may be one that is readily found in audio output circuits of many automobile radios and transistor power amplifiers. A modification of the invention provides for a coil in therelaxation portion of the circuit that may be from 500 to 1500 ohms resistance, and may draw about 7 to 12 milliamperes. The resistance of the relaxation circuit need be merely enough to allow the proper amount of current to charge the condenser of the RC circuit.

One of the important advantages in using transistors in a fence charger, and especially in the output stages thereof, is that the current drainage through the points of the coil vibrators and across the circuit contacts is very low in current, and for this reason these contact points may last a lifetime in the fence charging circuit. Due to the intermittent operation of the coils in the discharge path of the RC circuit, the average power for any given period is very inconsequential, and therefore a battery power or a low source of A.C. current may readily be used.

Among these advantages, it is also found that the invention provides for producing a pulsating stepup voltage derived from a relay arrangement so that there is derived a modern fence charger that can readily and efficiently be operated from dry cells, or a wet battery current source, or even a small A.C. current power pack that may derive its power from line current of 117 volts A.C.

Another object of the invention is to provide an improved electric stock fencer comprised of a new transistor circuit for producing a hotter, more efiicient and longer life equipment that is trouble-free and has less current consumption for providing longer life to the contact points that may be used in the fence charger.

In the improved fence charger of the present invention, it is seen that the fence charger is often used at the beginning of a season or period in which stock are sought to be maintained within the fencing, during which time the animals or stock find that the fence is hot. The fencer is then operated with a pulsating charge or spark of possibly to 15 shocks, and such pulsations or intervals occur approximately 48 times per minute. This pulsating current by a vibrator may be a low frequency pulsation unit delivering a substantial shock, rather than a sting or burn, but is often produced by many of the higher powered electric fencing equipment. The apparatus of the present invention is found not to harm surrounding environmental vegetation which is kept green but does not short out the fence to ground. Since the present invention operates from a substantially low frequency, it does not cause grass fires when the grass is somewhat dry, as is the case with fence chargers of the prior art.

In the practice of the present invention, the circuit may be changed from a rapid to a slow rate so that once the animals are made aware that the current is on the fence, the current can be switched to the single spark position, thereby achieving a small saving in battery drain.

A further object of the invention is to provide a 12 volt battery or a rectifier operated from a 117 volt A.C. current with a minimum DC. power drain.

These and other objects of the present invention will become apparent from a detailed description of the invention and from the appended drawings and claims.

In the drawings, the figure shows a circuit schematically showing the essential and important features of the improved electric stock fencer circuit, which is a preferred embodiment of the present invention.

Referring now to the drawings, the figure shows a source 10 which is a conventional 12 volt battery which may be of the dry or wet type. There is also shown as an alternative source 10a which may be connected as shown in dotted lines 12, 12 that provides for connecting the source 10a to the electric fencer in lieu of using the battery source 10. The source 10a comprises a full wave rectifier 14 that converts alternating current from a power line 16 to a 12 volt D.C. characteristic.

The source 10 is shown connected to an RC circuit comprising resistance R1 and condenser C100. The resistance R1 is provided with a tap connection for varying the value and time constant of the RC circuit. The condenser C is charged substantially to its peak voltage during a charging time controlled by the value of the resistance R1, and the electric field about the primary of T1 is established generally concurrently in time to the charging of C100 through the rectifier, and in a given case the charging time may be 48 times per minute. When th condenser is substantially charged completely, a trigger transistor X1, being of the unijunction type, is triggered by the value of the charge on condenser C100 so that it discharges the condenser through either relay L1 or L2 depending upon the position of the single-pole-doublethrow switch SW1. The switch SW1 is shown in the UP position so that the discharge of capacitor C100 is connected through reed relay L2 to the trigger transistor X1, and the armature or reed of the relay L2 is seen to vibrate several times due to the energization of the coil of the reed relay L2. The vibration of the armature of relay L2 makes and breaks the sets of contacts 1-2 and 3-4 so that the trigger or unijunction transistor X1 is grounded through contacts 3-4, and the contacts 1-2 when similarly closed provide for a shunt path to ground of the collapse current that may be generated in a primary winding or high voltage spark coil at T1 that is connected between ground and the high side of the power source 10 through a rectifier 20. While the rectifier 20 provides for a conductive path from the source through the primary winding of the high voltage spark coil T1, the collapse current is seen to be discharged or carried off through a transistor X2 by its base-collector circuit through the closed contacts, when such is the case, of contacts 1-2 to ground.

Similarly, with the switch SW1 in the DOWN position, the trigger unijunction transistor X1 then delivers through the reed relay L1 a current for causing the current to pass through contact points 5-6 for similarly discharging only the collapse current that is provided in the primary winding of the high voltage spark coil T1. This provides a different and varied rate of spark in the high voltage spark coil. The high voltage spark coil T1 includes a secondary winding 24 which is connected to the fence element 26 in a well known manner. The other end of the winding 24 is connected to ground, as is also Well known.

The operation is as follows: When one of the trigger points 2 or 6 is connected to ground or negative polarity, X2 is forward biased through the 10 and 12 ohm resistors and X2 base junction. X2 then switches between its emitter and collector circuit letting a large pulse of current pass from the plus junction 12 through emitter and collector and out into the primary coil of T1. At this time, the trigger points 2 or 6 break the circuit to the base junction of X2 which takes away the forward bias on the base of X2 causing the collector and emitter circuit in X2 to separate or switch olf. This interruption causes a quick rise of the voltage in primary coil 18 and with a reverse of polarity, diode 20 with its polarity indicated is placed across collector and emitter of X2 to protect X2 from this erratic voltage. The excessive voltage passes through 20 back to plus side 12. Transformer T1 steps up the voltage and connects with the fence wire.

It is apparent that the examples and modifications shown and described above have been provided solely by way of illustration and not by way of limitation, and these exemplary descriptions of the invention are variations and modifications within the scope of the present invention as defined and set forth in the accompanying claims.

What is claimed is:

1. Electrical fencing equipment comprising an RC circuit including a resistance and a capacitance for connection to a source of current supply, means for charging the capacitance,

an inductive discharge path including a vibrator reed relay,

a unijunction transistor trigger circuit coupled to the capacitance of said RC circuit to discharge the RC circuit through a vibrator reed relay of said inductive discharge path,

said reed relay having contacts that are opened and closed by oscillations of the armature thereof,

transistor means responsive to the opening of said contacts for applying a current to a primary winding, and

a rectifier circuit connected across said transistor means and responsive to the closing of said contacts for switching the primary winding to shorted relation.

2. Electrical fencing equipment comprising an RC circuit including a resistance and a capacitance for connection to a source of current supply, means for charging the capacitance,

a vibrator reed relay energizable upon discharge of the capacitance of the RC circuit,

a trigger means coupled to the RC circuit to couple the discharge of the capacitance thereof to the vibrator reed relay,

said vibrator reed relay having contacts that are opened and closed upon oscillations of the armature thereof,

transistor means responsive to the opening of said contacts for applying a current to a high voltage spark coil, and

a rectifier circuit connected across said transistor means and responsive to the closing of said contacts for shorting the collapse current of the high voltage spark coil to ground.

3. Electrical fencing equipment of claim 2 wherein the trigger circuit is a reed relay, and in which said source is a battery.

References Cited UNITED STATES PATENTS 2,594,595 4/1952 Stearns 32l49 X 2,685,056 7/1954 Hester 321-49 3,115,610 12/1963 Beguin 331-111 X 3,182,227 5/1965 Brittain et a1 317--148.5 3,202,884 8/1965 Bullock 317-1485 3,218,793 11/1965 Walton 331-116 ORIS L. RADER, Primary Examiner.

T. B. JOIKE, Assistant Examiner.

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