US1774874A - Protective device - Google Patents

Description

Sept' 2, 1930. H. A. EATHERToN PROTECTIVE DEIGE Filed Nov. 22, 1927 2 Sheets-Sheet l Sept 2, 19h30. H. A. EATHERTON 1,774,874

HOTEGTIVE DEVICE Filed Nov. 22, 1927 2 Sheets-Sheet 2 Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE HARRY A. EATHBTON, or FINDLAY, omo, Assreivoa. 'ro PORCELAIN rnonuc'rs, INC.,

or FINDLAY, oHIo, A conroaA'rIoN or DELAWARE v PROTECTIVE DEVICE Application led November 22, 1927. Serial No. 235,055.

The present invention has reference to protective devices for electrical circuits and deals more particularl with that class of protective devices whic is utilized to protect radio circuits and the like from the eifects of high voltages whether produced by lightning, adjacent power lines, or static discharge.

Stated more specifically this present invention relates to a type of protective device having two electrodes separated by a gap of such a character that abnormal voltages will cause a discharge from one electrode to the other,

one of the electrodes being grounded.

It is an object of the present invention to produce a protective devlce of the nature described which will function to protect the circuit with which it is used from the eiect of abnormal voltages.

It is a further object of the present invention to provide a protective device of the nature described which is specially adapted for use in connection with the protection of radio apparatus and circuits.

It is a still further object of the present invention to provide a method of manufacture for protective devices of this nature by means of which the protective devices can be quickly and easily assembled and the proper gap formed between the electrodes.

It is a still further object of the present invention to provide a method of manufacture of a protective device ofthe nature described in which the proper relationship of the electrodes is obtained through the subsequent change of temperature of some of the materials used or applied in a heated state.

The present invention will be better understood by reference to the accompanying drawo tion, various forms of the protective device and its method of manufacture.

Referring to the drawings, Fig. 1 is a view of a preferred embodiment of the protective device;

Fig. 2 is a section of the deviceshown in Fig. 4 is a partial sectional view illustratings which show for the purpose of illustraing a method of assembling the preferred embodiment.

Referring now to the figures, and more particularly to Figs. 1 and 2, the embodiment herein shown comprises insulating receptacle 1 constructed of suitable insulating material such as glazed porcelain. This receptacle is constructed with an upper truncated conical portion 2, the lower end of which extends out and beyond a plurality of concentric corrugat'ions 3 and 4, the purpose of this construction being that of providing as high a resistance path as possible between the upper and lower portions of the insulating receptacle under all weather conditions. A central aX-- ial tubular opening 5 extends through the rcceptacle.

A pair of electrodes 6 and 7 of brass or other suitable'material are mounted within the opening 5 with their inner ends closely adjacent but spaced from each other as shown l so as to form a gapof such a nature as to permit abnormal voltages to discharge from one electrode to another. For the purpose of making clear the structure, this gap is shown in the drawings, but in the actual structure the gap is microscopic in character. While not essential to the present invention the electrodes 6 and 7 are provided in the described embodiment with enlarged heads or ends 8 and 9 between which the gap is formed.

l The outer ends of the electrodes 6 and 7 are threaded and provided with nuts 10, 12, for the purpose of incorporating the protective device into the electrical circuits with which it is associated. For instance a, ground wire may be clamped between the nuts l,12 while an antenna and associated lead-in may be clamped between the top nuts 10 when the protective device is usedin connection with radio circuits.

In order to suitably hold the electrodes 6 and 7 in the desired position with respect to each other and with respect to the receptacle 1 the central opening 5 is filled with some suitable insulating material 13 such as sulphur which may be placed in the opening in the molten state, in a manner to be later referred to.

A metal screw eye 14 or similar attaching A10c device is provided asa means of support for the insulating receptacle containing the electrodes. Thev eye of the attaching means 14 loosely surrounds the receptacle in the groove between the corrugations 3 and 4 so that the receptacle may be used as a handle for the rea the screw eye in any suitable support such 'asa Window casing. At` the same time the and insulating receptacles as just described in connection with the structure shown in Figs. 1 and 2, is permanent in character. In certain instances it may be desirable to provide an assembly of the mounting member and insulating receptacle which may be readily disconnected when desired, as in some instances it may be desirable to remove the electro mounting member and use the device without the same.

Fig. 3 illustrates a modification for this purpose in which the eye of the mounting member 14 engages the insulating member below the corrugation 3 around the portion 4a of the insulating receptacle. In order to accommodate the eye of the supporting member 14 in either of the two positions the corrugated portion of the insulating receptacle is formed with the diameter of the same at 3a and at 4a. The mounting member 14 as shown in Fig. 3 is held in loose assemblage with the insulatingreceptacle by means of the washer 15 which in turn is held in place by the lower nut 12. If it is desired to disconnect the mounting member from the rest of the structure it is only necessary to remove the lower nuts 12 and remove the washer 15 after which the mounting member 14 may be removed.

Reference is next had to the method of manufacture of the protective device in order to assemble the component parts of the structure, and an apparatus of the form shown in Fig. 4 may be used to hold the parts in proper relationship for assembly although it is to be understood that the use of the specific apparatus here shown is not necessary and numerous other forms of apparatus may be used instead. As shown in Fig. 4 the protective device is assembled in inverted position upon a base or holder 16. The base is provided with a vertical hole 17 into which the electrode 6 is inserted, the hole 17 being of the proper depth to properly position the electrode with respect to the insulating member or receptacle 1 which is subsequently inserted in the enlarged conical concentric opening, which thereby centrally locates the e with respect to the opening 5. The

y insertion of the threaded portion ot electrode 7 is then inserted with its inner end or head 9 resting directly in contact with the head 8 of the other electrode. A vertical movable member 18 having a recess 19 in its lower end is then depressed by theoperator against the spring v20 the member 18 being slidably mounted in the arm 21 which in turn is supported by the column 22. By this means the electrode 7 is also centered with respect to the insulating receptacle and is maintained in -axial alignment with respect 'to the other electrode 6.

\.\While the electrodesfand insulating receptacle are thus held in substantial assembled position, insulating material which is molten while in a heated state such as sulphur, is poured into the central axial opening from a ladle 23. As soon as the central opening has beenfilled and has begun to-'solidify, member 18 may be allowed to return to its upper position and the device may then 4be removed.

By the method of construction just described, an inherent formation of the gap between the electrodes 7 and 8 takes place, upon the cooling and solidification of the insulating material 13.

While it is of course not necessary to a practice of the present invention to know the cause of the gap thus forming, the followingl theory is advanced as a probable one. As the molten material'is poured into the central opening it causes the electrodes of brass or other metal to become heated and expand therefore increasing their length slightly. As the sulphur or other molten material begins to solidify this action will naturally take place at the top and bottom of the central opening, where the cooling eiect is greatest, so that the electrodes are at first held rigid with respect to the enclosing insulating medium at their outer extremitles. A continued cooling of the insulating material 13 with its consequent solidification progressing toward the center will cause the electrodes to shrink or to decrease their length as temperature conditions return to normal, thereby causing a separation or a gap to occur between the heads 8 and 9.

By a proper portioning o parts a suitable gag may thus be formed. While not desiring to e limited to any kind of material for the various parts of the device, or to any size of structure, the invention may be readily practiced by those skilled in the art by using a porcelain insulating receptacle Ahaving central opening therein approximately 21/2 inches long and 1/2 inch in diameter in which two electrodes of brass are inserted, the electrodes being approximately E inch in diameter, the insulating material being sulphur lfieatled to a suiiicient degree to cause it to flow It is of course to be understood that the present invention may be carried out with other materials and it is also pointed'out that another advanta e exists in the above de'- scribed method o assembly, in that if the gap between the electrodes is not of the correct size the same may be readily adjusted before the insulatin material has had time to completely solidlfy by suitable manipulation of the nuts or 12.

In certain forms of protective devices for 10 the purpose described, the functioning of the device is de endent upon other constructions than a gap etween two electrodes. It is to be understood that the form 'of insulating receptacle and its supporting structure as de? "i scribed and claime is equally applicable to these other forms of protective devices.

Various modifications of the device are shown in the drawings described in the s ecification will suggest themselves to t ose skilled in the art and are to be accordingly considered as coming within the sco e of the present invention and the appende claims.

.What I claim is: 1. A protective device comprisin in combination, an insulatin receptacle avin'g a central opening theret rough, a pair of metallic electrodes located in axial alignment within said opening witha space' between their ends andmeans com risin an insulat- 31 ing sleeve cast aroun sai electrodes throughout the full len h of said opening flor holding said electro es in fixed relations 1p.

2. A protective device comprisin in com- 35 bination, an' insulatin rece tacle aving a central opening theret roug a pair of metallic electrodes, located in axial alignment within said opening with a space between their ends and means comprisin an unitary v solidified insulating member or holding said electrodes in fixed relationship. 3. A protective device comprisin in combination, an insulatin rece tacle aving a central opening theret roug a pair of metallic electrodes located in axial alignment within said opening with a space between their ends and means comprising an unitary solidified insulating'member cast in place in said tubular opening for holding said elec- 5o trodes in fixed relationship.

4. A 'protective device comprising in comp bination an integral insulatin receptacle havmg a bottom portion of cylmdrical corrugated form and a top portion of truncated conical form, the lower edge of which projects beyond the bottom corrugated portion thereof, spaced electrodes located with said receptacle and supporting" means for said receptacle including an eye loosely associated with sald corrugated bottom portion of said receptacle. l In testimon whereof,Iaixm si nature. ARRY A. EATH'lR ON.

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