US2650325A - Lightning arrester - Google Patents

Description

Augr25, 953 ,E.J. EHRBAR I 2,650,325

LIGHTNING ARRESTER Filed Dec. 6, 1951 v I v IN VEN TOR. EDWARD J El/REAR LWWW ATTORNEYS Patented Aug. 25, 1953 LIGHTNING ARRESTER Edward J. Ehrbar, Cleveland, Ohio, assignor to Cornell-Dubilier Electric Corporation, South Plainfield, N. J., a corporation of Delaware Application December 6, 1951, Serial No. 260,209 7 Claims. (Cl. 315-41) This invention relates, as indicated, to lightning arrestors, but has reference more particularly to an arrestor which has been designed especially for use in connection with television antennas.

At the present time, various types of lightning arrestors are used, including arrestors of the air gap, resistive and neon lamp discharge type, each of which, due to the internal capacities provided by their mechanical construction, offer line insertion losses which are raised as the frequency of the received signal is increased. This is an inherent electrical property of all of the aforesaid types of arrestors.

The antenna or lead-in lines to which the aforesaid types of arrestors are attached for protective service are placed above ground, electrically, by a resistance equivalent to that built into the resistor by the manufacturer of the arrestor, which resistance ranges from one-tenth of a. megohm to infinity. This restricts the static or stray discharge rate. In the neon type arrestor, the static charge must reach a minimum of 60 volts before conduction, and the air gap 500 volts, before discharge occurs.

The present invention has as its primary object, the provision of a lightning arrestor which overcomes the disadvantages or shortcomings of existing types of arrestors, and which effectively places the antenna, lead-in or transmission line at ground potential.

Another object of the invention is to provide a lightning arrestor, having an inductance, the resistance of the arrestor, which is limited by the D. C. resistance of the inductance from any electrode to ground, being less than one ohm.

A further object of the invention is to provide a lightning arrestor of the character described, the impedance of the inductance of which is so arranged that it is high enough to offer no signal attenuation for the frequencies which it is designed to pass.

A still further object of the invention is to provide a lightning arrestor of the character described, which is of extremely simple construction, consisting of a minimum number of easily manufactured and readily assembled parts, and

which can be made and sold, in commercially feasible quantities, at relatively low cost or expense.

Other objects and advantages of my invention will be apparent during the course of the following description. In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same.

Fig. 1 is a top plan view of a lightning arrestor, embodying the novel features of the invention;

Fig. 2 is a bottom plan view of the lightning arrestor;

Fig. 3 is a view, partly in side elevation, and partly in cross-section, taken on the line 3--3 of Fig. 1, and

Fig. 4 is a view, illustrating in a somewhat diagrammatic manner, the use of the aforesaid lightning arrestor.

Referring more particularly to the drawings, the lightning arrestor will be seen to comprise a rectangular housing or casing I, formed of an electrically-insulative material, and having in its upper face 2, an elongated recess 3, which extends diagonally across the housing.

Disposed within the recess 3 is an inductance coil 4, the ends 5 of which are secured to contacts 6, which are fastened to the base 1, of the recess 3 by means of screws 8 and 9.

The screws 8 extend through the housing I and their stems project from the bottom of the housing, said extensions being provided with cupshaped washers I8 having serrated edges I9, and with nuts I0, so that the wires II and I2 (see Fig. 4) of a television antenna lead-in or transmission line may be electrically connected to the screws between the nuts 9 and Washers l8.

A wire I3 extends from the mid-point of the inductance coil 4 and is soldered to a contact I4, which is removably secured to the casing I, as by a screw I5, which is adapted to be connected to a ground I6. Air gaps I! are provided between the wire I3 and the wires II and I2.

The arrestor, as thus described, is highly advantageous in that it places the antenna lead-in or transmission line (consisting of the wires II and I2) at ground potential. The arrestor has an inductance, represented by the coil 4, the D. C. resistance of which from any electrode to the ground being less than one ohm. The impedance of the inductance is sufliciently high so that it offers no signal attenuation for the frequencies which it is designed to pass.

The arrestor is of extremely simple design and construction, and consists of a minimum number of parts which are easy to manufacture and assemble, so that the arrestor can be made and sold in commercially feasible quantities, at relatively low cost or expense.

It is to be understood that the form of my invention, herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, 1 claim:

1. In a lightning arrestor for the protection of television antenna lead-in lines, a housing, an inductance coil in said housing, the ends of coil being adapted for connection to the wires of a lead-in line, a wire connected to and eX- tending from the mid-point of said coil and adapted for grounding, wires connecting said wire with the wires of said lead-in line, and gaps in said last-named Wires.

2. An ar ester, as defined in claim 1, which places said lead-in at ground potential.

3. An arrestor, as defined in claim 1, the inipedance of the inductance of which is so arranged that it is high enough to offer no signal attenuation for the frequencies it is designed to pass.

4. In a lightning arrestor for the protection of television antenna lead-in lines, a housing of insulation material having an elongated recess in its upper face e tending diagcnaily acress t housing, an stance coil in recess, contacts secured to the base of said recess adjacent the ends thereof, said coil having ends secured to said contacts, a third contact secured to the wall of said housing, and a wire extending from 4 the mid-point of said inductance coil to said third contact.

5. A lightning arrestor, as defined in claim 4, in which said third contact is of inverted U- shaped configuration, with one leg of the U disposed externally of the housing and the other leg of the U disposed internally of said recess.

6. A lightning arrestor, as defined in claim 4,

in which said first-named contacts are secured to the base of said recess by means of screws and, nuts, the nuts being disposed adjacent the lower surface of said housing.

7. A lightning arrestor, as defined in claim 6,1

in which additional nuts are secured to the stems of said screws, whereby wires from said antenna lead-in line may be electrically secured to said contacts.

EDWARD J. EHRBAR.

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