US 1438954 A
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Description (OCR text may contain errors)
I N V EN TOR.
G. R. FOLDS.
FILED NOV. 12, 1919.
E WK Dec. 19, 1922.
Patented Dec. 19, 19 22.
uylrao STATES PATENT-OFFICE.
GEORGE R. FOLDS, O]? EVANSTON, ILLINOIS, ASSIGNOB TO COOK ELECTRIC COMPANY,
OF CHICAGO, ILLINOIS, A CORPORATION OF. ILLINOIS.
Application filed November 12,1919. Serial 110. $3 7,510.
T 0 all whom it may concern.
Be it known that I, Gnono'n R. Forms, a
citizen of the United States, residin at the interior of a pole'ca Evanston, in the county of Cook and tate of Illinois, have invented new and useful Im rovements in Lightning Arresters, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.
This invention relates to lightning arresters, and more particularly to improved means for electrically separating the line and ground springs of lightning arresters used on low voltage electric circuits, such as telephone, telegraph and signal systems to provide for high potential discharges.
Lightning arresters used for high potential discharges on low voltage electric circuits are equipped with means whereby a discharge gap is provided to consummate the high potential discharges.
The construction herein comprises two conducting plates, preferably constructed of either carbon or copper, and separated by a suitable dielectric, the high potential jumping from one plate to the other.
One object of my invention is to provide an improved form of saw tooth type arrester, in which a serrated or toothed edge is separated from a suitable ground plate by the desired air space to insure the discharge of a determined minimum potential.
Another object of this invention consists in the production of an improved and efiicient form of separating means for a saw tooth arrester construction, which means may be readily assembled and which consists of parts which, when assembled, clampingly engage each other to constitute an integral unit whereby when the separating means is removed from the arrester, it is removed as a single piece. This obviates the handling of a plurality of parts when the separating means are inserted and removed from arresters, and thus avoids much inconvenience due to the dropping and losing of the individual parts used' in constructing said separating means.
Other objects of the invention will become apparent from the following description, the accompanying illustrations and the ap pended claims.
For the purposes of illustration and description, the specific embodiment of this invention is shown in the accompanying drawingsand inwhich-v i "Fig. 1 illustrates a perspective view of b e terminal equipped with the .lmproved arrester separating means;
Fig. 2- illustrates in perspective the respective parts of the saw tooth arrester separatin means shown in Fig. 1 disassociated rom one another but ositioned in the respective order in which t ey are combined when placed--in position in the light- IllIl arrester; and
ig. 3 illustrates a view in perspective of the assembled saw tooth arrester separating means.
The improved form of arrester separating means herein illustrated and described can obviously be used with substantially any and all kinds of commercial lightning arrester constructions, and is shown and described herein in connection with a pole cable terminal for illustrative purposes only. The pole cable terminal illustrated is well known to those skilled in the art, and a very brief description thereof will consequently be sufficient. This pole cable terminal box 10 is provided with a cover 11 and side panels 12 extend vertically from the base 13 of the cable terminal box, said panels being sesured to the base and upper portion of the terminal box by means of angle members 14. Suitably mounted on the vertical side panels 12 are spring clips 15 and 16 which receive fuses 17 which are held in said clips with a permanent tension.
The line wires 18 enter the base portion of the cable terminal box and are fanned out and electrically connected to the spring clips 15 as shown at 19. The cable wires 20 also enter the cable terminal box through the base portion thereof, said cable wires 20 being likewise fanned out and electrically connected to the inner s. ring clips 16. In the ordinary operating 0 the apparatus, the line current will flow from the line wires' 18 through the spring clips 15, the fuse member 17, through the spring clip 16 and out to the cable wires 20. To prevent any damage to the cable wires 20, a lightning arrester 21 is located between the spring clip lish a by-pass for high potentials whereby such high potentials will not reach the cable but will be shunted through the arrester to ground, thus preventing the burning-outs in the cable.
The lightning arrester comprises the spring clip 16, the ground panel 12 and the improved separating means hereinafter to be described in detail. The separating means is fitted with a plate 22 having a serrated or saw toothed edge, but obviously this plate could be constructed in any other desired form or shape. The plate 22 has integrally formed... inwardly extending flanges 23 and 2.4:,the flange 23 having a serrated 01' saw toothed edge as illustrated at 25. This plate is made of conducting material, preferably sheet brass, and is equipped with the upset portions 26 which are adapted to properly guide and position the plate in the arrester spring clip 16.
Positioned between the flanges 23 and 24 of the plate 22 is a dielectric 27 which is composed of some suitable non-conducting material, preferably celluloid or mica. This dielectric fits into and conforms to the contour of the flanged plate 22, whereby the non-conducting material extends to the saw toothed edge of this plate and extends beyond the opposite flange portion 24.
A carbon block 28 is positioned next to the grounded vertically extending side panel 12 and is in electrical contact therewith. This carbon block is fitted with a central slot 29 whereby said block may be used either next adjacent the side panel ground plate 12 or in connection with the spring clip 16 in which case the slot serves to properly position and securely hold the block 28. As shown in Figs. 2 and 3, the carbon block is cut away on the opposite side from said slot 29 so as to form shoulder portions 30 whereby the block may be inserted between the flange portions 23 and 24 of the plate member 22, which arrangement with the dielectric held therebetween form an integral unit.
As shown in Fig. 3, the saw tooth separating means is so formed that the parts may be assembled as an integral unit before being inserted between the side panel ground plate 12 and the spring clip 16 of the lightning arrester. In assembling the parts of the separating means, the dielectric 27 is first placed inside of the plate 22 with its inwardly extending flanges resting against the flanges 23 and 24 of said conducting plate. The plate 22 with the enclosed dielectrio is then slipped over the cut away portions 30 of the carbon block 28, said plate with the enclosed dielectric snugly fitting over this portion of the block 28. It will be evident, therefore, that the carbon block 28, conducting plate 22 and dielectric 27 may be assembled before being inserted between the side panel ground plate 12 and the spring clip member 16 in which condition it is preferably carried in stock and in the tool kits of the repair man and the troubleshooter. The advantages of this construction, therefore, reside in the fact that there is little, if any, danger of the parts becoming separated and of the parts of the arrester being lost or mislaid, as frequently happens to mica or celluloid due to its transparency when separated from the other elements of the separating means.
When the various elements, namely, the conducting plate 22, dielectric 27 and carbon block 28 are all assembled in position, asillustrated in Figs. 1 and 3, it will be evident that the carbon block is in direct contact with the ground member and that the plate is in direct dielectrical" contact with the spring clip 16.
However, there is no electrical contact between the carbon block 28 and the plate 22 since they are insulated from each other by the dielectric 27. The toothed edge of the plate is separated from the shoulder 30 of the carbon block 28 by the thickness of the dielectric, the parts being so manufactured that when the dielectric is placed between the plate and'the carbon block, this desired distance between the toothed edge of the plate 22 and the carbon block 28 is maintained in order to provide for the discharge of the minimum potential at which the arrester is designed to operate. The dielectric consequently may be the means utilized to give the desired separation between the saw toothed edge of the plate electrically connected to the spring clip 16 and the shoulder portion of the carbon block connected to the ground member 12.
From the preceding description, it will be evident that when the various elements shown in Fig. 2 are assembled in their cooperative positions, the line wire 18 is connected to the conducting plate 22, and the side panel ground member 12 is in contact with the carbon block 28, the carbon block being separated from the plate by means of the dielectric 27. The high potential will consequently be discharged through the toothed edge 25 to the carbon block 28.
Further, when for the purposes of inspection, replacement or repair it becomes necessary to remove the separating means, the said separating means will be removed as an integral unit, thereby avoiding the handling of a plurality of parts and the separation of the plate, dielectric or carbon block.
If replacement is desired, the inspector can obviously take an assembled separating unit from his kit and insert it in place without wasting any time in handling the small parts of which it is built.
This invention is not limited to the specific embodiments herein illustrated and described, but it is capable of many variations and modifications which come within the spirit and scope of the invention .as set forth in the following claims.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:
' 1. In a lightning arrester in combination, line and ground members, an assembled integral unit electrically separating said members including conducting members separated by a dielectric, said conducting members being mechanically connected to each other through a dove-tail joint the tenon and mortise of which. are electrically separated by said dielectric, and means forming an electric discharge path between said conducting members.
2. In a device of the character described in combination, an assembled integral unit comprising a metallic plate having a flange portion, the edge of sa1d flange portion being serrated, a conducting block, and a dielectric between said metallic plate and conducting block, said conducting block, metallic plate and dielectric snugly engaging each other to form said assembled integral unit.
3. In acdevice of the character described in combination, an assembled integral unit comprising a metallic plate having flanges thereon, a dielectric conforming to said plate and flan es and received between said flanges, a con ucting block received between the flange portions of said dielectric, said metallic plate, dielectric and conducting block snugly en aging each other so as to form said assembled integral unit.
4. A lightning arrester comprising a metallic plate in the form of a mortise having a serrated longitudinal edge, a conducting block provided with a tenon to engage said mortised metallic plate and with a lateral flange portion, a dielectric interposed between said plate and said conducting block, and means for properly locating the assembled members in operative position, said serrated edge being spaced from said lateral flange ortion which it subtends.
5. A lightning arrester comprising a conducting member in the form of a mortise, a second conducting member in the form of a tenon to engage said mortise thereby forming a dove-tail joint connection between said conductin members, one of said conducting members being provided with a longitudinally extending serrated edge that is spaced from the other of said conducting members, and a dielectric for electrically separating said conducting members from each other.
6. A lightning arrester comprising two conducting members one of which is provided with a serrated edge, said members being mechanically connected to each other through a dove-tail joint, and means for electrically insulating said members from each other, said serrated edge serving as an electric discharge path from one of said members to the other from which it is spaced to form a spark-gap.
7 A lightning arrester comprising a conducting member in the form of a mortise, a second conducting member in the form of a tenon to engage said mortise thereby forming a dove-tail joint connection, one of said members being provided with a longitudinally extending serrated edge that is spaced from the other of said members, a dielectric for electrically separating said members from each other, and means for properly loeating the assembled members 1n operative position.
In witness whereof, I have hereunto subscribed my name.
GEORGE R. FOLDS.
J. 0. Boom, B. C. Mnnm.