US 2473363 A
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Description (OCR text may contain errors)
June 14, 1949. J 3, 300 ET AL 2,473,363
WIRE SUPPORTING DEVICE Filed Nov. 26, 1945 "Hilllllllllllmllll Patented June 14,, 1949 UNITED STATES PATENT OFFICE WIRE SUPPORTING DEVICE John Brown Cook and Leonard L. Jugle, Chicago, Ill., assignors to Reliable Electric Company, Chicago, 111., a corporation of Illinois Application November 26, 1945, Serial No. 630,857
1 Claim. it
This invention relates to an improved construction for a wire supporting device which is used in connection with power transmission and distribution lines.
In transmission line practice it is frequently desirable to support the wire from the supporting arm by so--called dead end practice. This means that the end of each span of wire is supported by a strain insulator assembly in the same manner as if it were a dead end wire. Such strain insulator assemblies are used in connection with the adjacent ends of adjoining spans, and instead of using a separate jumper to connect the adjacent spans, the continuity of the wire is not broken, but directly connects one span with the other.
Such dead end strain insulator assembly usually includes a wire supporting member around which the wire may be looped or snubbed, and by means of which the tensile stress is transferred from the wire to the strain insulator. Such a member is grooved in order that the wire may be retained in position.
Such wire supporting members in the past have often been castings.
When an aluminum transmission wire is used, it is desirable to provide an aluminum wire supporting member, but the aluminum castings previously used are objectionable due to their comparatively high cost.
It is an object of this invention to provide a wire supporting member fabricated from sheet material which may be manufactured at less cost than the cast aluminum fittings heretofore used.
It is a further object of this invention to provide a wire supporting member which is fabricated from two plates which are secured together, the construction being such that fleXural stresses are virtually eliminated, and the tendency to buckle is greatly minimized. Thus, a construction is provided which is practical for a non-fer: rous metal, such as aluminum.
That embodiment of the invention which is herein shown and described is often referred to as a thimble. When thimbles are used in dead end practice, the wire is secured to itself, in front of the thimble, :by suitable connecting means. However, it is obvious that this invention is equally applicable to other types of wiresupporting members, such as those referred to as snub type dead ends, in which the construction is such that the wire supporting member exerts a more marked snubbing action, and the free end of the wire is clamped to the snub type dead end, rather than to the span itself.
Other objects, features and advantages will become apparent as the description proceeds.
With reference now to the drawings, in which like reference numerals designate like parts Fig. l is an elevation of a, transmission line supporting means embodying this invention;
Fig. 2 is an end view of one of the thimbles shown in Fig. 1;
Fig. 3 is an elevation of the thimble shown in Fig. 2;
Fig. 4 is a right hand end view of the thimble of Fig. 3; and
Fig. 5 is a plan View of the thimble of Fig. 3.
With reference now to Fig. l, the reference numeral II designates the usual pole having cross arms l2. Insulators l3 are mounted on the cross arms by means of bolts 14, and the insulators also include supports l5 on which the thimbles iii are mounted. It will be seen that the wire ll, or other suitable conductor, is looped around the thimble l6, and then is secured to itself by means of split bolt connectors I8. By means of this construction, the stress of that portion of the wire I! which forms the span 30' between adjacent poles, is uniformly divided between the two halves 3! and 32 of the loop. That portion of the wire I! which connects span 30 with an adjacent span 33, and which is relieved of the stress of the two spans, is designated by the reference numeral 34.
The thimble, as shown in Figs. 2 to 5, inclusive, comprises two plates [9 and 20, the central portions 2! and 22 of which are secured to each other by a plurality of rivets 26. The main portions of plates I9 and 20 are of circular shape, and the marginal portions are offset to form offset edges 23 and 24. These offset edges cooperate to form a groove 25 which, in the embodiment shown, extends through an arc of 270 degrees, more or less. That side of the thimble which faces the span may be cut off, as shown in Fig. 3, to save material, inasmuch as it is necessary to provide a groove 25 which extends through an arc sufficiently long to provide only tangential contact with the two halves of the loop of the wire H.
The plates l9 and 20 are also provided with rearwardly extending supporting arms 2'! and 28 which are apertured as indicated at 29 to provide a means by which the thimble l6 may be secured to the support 15 of the insulator I 3.
In operation, it will be evident that the wire I! is disposed in the are shaped groove 25, the groove being of sufficient radius with respect to the diameter of the wire so that undue strains are not imposed on the wire due to the bending thereof. The V-shape of the bottom of the groove 25 provides a secure seat for the Wire, and the tendency of the plates to separate, due to the force exerted by the Wire on the bottom of the groove, is successfully resisted by disposing the rivets 26 closely adjacent the bottom of the groove. It will be noted that a Whole series of rivets is thus provided so that @the strain on any one rivet is not excessive.
In that embodiment of this invention which is shown herein, it will be seen that the central portions of the plates form a web which takes up the axially directed force exerted by the wire on the bottom of the groove. Thus, the groove itself is not subjected to the flexural stress which "is I present in the usual type thimble, and which tends to deform the groove portion. :Any tendency of the separate plate portions to buckle is minimized by the disposition of the rivets closely adjacent the bottom of the groove, and the provision vof aplura'lity of rivets spaced at substantially 3.0 degree intervals.
The use of the construction :herein :shown permits manufacture of a :thimblie from sheet metal b-ya stampingoperation, @whichismuch less costly than either :the aluminum castings heretofore used, or therfabrioation of-zan ordinary thimble.
The construction herein shown .isparticularly well adapted \for use in connection with aluminum sheet, due to the reenforcing effect exerted invention have been shown and described herein,
central portions, and ofiset marginal portions which cooperate with each other to form a curved zg-roove, a series of rivets passing through said .central portions and securing them to each other,
said rivets being spaced adjacent the bottom of the groove formed ,by said marginal portions, and saidplates beingshaped so that each of said marginal portions is provided with an extension, said extensions being oppositely disposed and providing supporting arms for said thimble.
JOHN BROWN COOK. LEONARD L. JUGLE.
REFERENCES CITED The following references are of record in :the
.' file of this patent:
UNITED STATES PATENTS Number Name Date v1,073,292 -Shnable Sept. 16, 1913 "1,177,046 Nice Mar. 28, 191.6 1,475,627 Gates Nov. 27, 1923 2,007,913 Durr c July 9, 1935