US1729532A - Electrical insulator - Google Patents

Description

o. P. lEscHE 3,729,532

ELECTRICAL INsULAToR Sept. 24, 1929 Filed Feb. 2 11,92%

Patented Sept. l24, 1929 UNITED STATES PATENT OFFICE OTTO PAUL ZIESCHE, F HERMSDORF, THRINGEN, GERMANY, ASSIGNOR TO HERMS- DORF-SGHOMBURG-ISOLATOREN Gr. M. B. H., OF HERMSDORF, THRINGEN, GER- MANY. y

ELECTRICAL INSULATOR Application led February 2, 1928, Serial No. 251,386, and in Germany January 27, 1926.

This invention concerns a method and means for securing parts of electrical insulators, such as supporting pins, strain pins and the like, in said insulators, without the use of cement.

According to the invention, for securing an' inner element of an electrical insulator such as the supporting element, strain pin or the like, inside another element thereof,

use is made of a deformable member, for eX- ample a deformable copper sleeve, which is adapted to be introduced together with the inner element into a cavity in the outer element, usually the body of the insulator, and

l5 to be deformed therein, as by being spread, for the purpose of holding said inner element Ain the outer element.

In the case of ordinary supporting or strain pins, which usually include a stem portion Z0 surmounted by a mushroom-shaped or other head, a deformable sleeve may be slid over the stem, introduced together with said pin 'through a constricted opening into the cavity in the insulator body and spread therein by l5 being buckled or expanded with suitable tools so as to prevent the pin being subsequently withdrawn through said opening. Lead is then cast-in around the pin in' the normal manner and an attachment thus effected c which is easy to produce and certain in its effect, although no cement is used.

Examples of applications of the present invention will now be explained by reference to the accompanying drawings in which:

5 Fig. 1 illustrates in sectional elevation the commencement of the ope-ration of securing a strain or suspension pin in a suspension insulator,

Fig. 2 shows the parts of the same insulator o in their positions on the termination of said operation,

Fig. 3 illustrates the application of the 1nvention to a supported insulator (pin insulator), and

5 Figs. 4 and 5 illustrate two examples of deformable sleeve-shaped members employed in the attachment.

Referring to Figs. 1 and2 of the accompanying drawing, illustrating avsuspension,

o type insulator, the suspensionmeans include a dumb-bell shaped pin K with an up er mushroom shaped enlargement or head 72, thel lower side ofwhich is flat and substantially at right angles to the axis of the pin. A sleeve H of copper or a similar appropriate material is arranged over the stem or shaft of the dumb-bell shaped pin K and together with the latter, said sleeve is introduced as far as possible into the interior of the insulator. A tubular supporting tool D, which is preferably in two parts and rests upon a fixed base U, is then arranged around the pin stem which is engaged by. an appropriate tong-shaped drawing'device M whereby it is pulled downwardly with a force Z. In this manner the central portion of the sleeve H is buckled to such an extent that its external diameter becomes greater than the internal diameter of the narrower or constricted mouth -of the cavity in the insulator and consequently, together with the pin K, it can no longer be withdrawn therefrom. Owing to the shape -of the head V2 which affords a secure seat to the sleeve by means of its downwardly facing lower side, the upper margin of the sleeve remains unexpanded and in contact/With the lower face. The insulation proper J which to a certain extent rests on the pin K during the operation is not mechanically stressed in the course of the expanding process.

A suspension pin usually has a knob shaped enlargement V1 at its` lower end whereby is suspended the next insulator of the chain. For the purpose of the present invention. this knob-shaped enlargement is produced most simply by upsetting after the sleeve H has been slid into position; it then offers a convenient point of engagement for the tongshaped tool M.

By suitably shaping the sleeve it is possible to arrange that in its nal condition after buckling the lower edge thereof engages in a groove R in the stem of the pin K, the deformed sleeve thus being secured at the end of said stem.

rlhe pin is finally properly centered and a layer of lead of sufcient thickness as shown at S in Fig. 2 is cast in to i'ill the space between the sleeve and the inner surface E of vthe insulating body. Preferably, the sleeve is so dimensioned that the point of contact of its lower rim with the pin K will be located at the inner end of the constricted mouth of the cavity. Thus, the mouth afl'ords an un obstructed passage to the lead lilling which is to be poured in in a molten state to fill the remaining space in the cavity.

Grooves A1 in the insulator body and flats A2 on the shaft of the dumb-bell pin K not only prevent rotation of the filling relatively to the insulator body J but also rotation of the stem of the pin relatively to the lead lilling.

The cap of the insulator, if such is provided, may be secured with cement in the normal manner. A

Fig. 3 illustrates the application of the invention to the cementless fixing of supporting pins and the like in pin insulators.

its central portion mounted on said pin Within the cavity adjacent the lower side of the head and being of suiiiciently reduced length to leave the restricted opening unobstructed,y

signature.

OTTO PAUL ZIESCHE.

The sleeve may be of cylindrical shape, as

illustrated in Fig, 4 or of a swollen or barrel shape, Fig. 5. To facilitate the buckling of the sleeve into its final condition, a groove or grooves r reducing the strength of the sleeve, may also be provided.

I/Vhat I claim is:

l. In combination, an electric insulator body having a cavity therein provided with a restricted opening, a pin provided with a head having a lower face substantially at right angles to the axis of the pin extending into said cavity, a one piece sleeve of continuous periphery buckled about its central portion to form an annular collar mounted on said pin adjacent its lower face within the cavity of the insulator body, and a metal illing cast into said cavity to ill the remaining interior space, the buckled portion of the sleeve being ofgreater diameter than that of the restricted opening of the cavity.

2. In combination, an electric insulator `having a cavity therein provided with a restricted opening, a top and sides, a pin extending through said opening and into'said cavity, a head on the portion of the pin within the cavity having a lower face substantially at right angles to the axis of the pin, a sleeve buckled outwardly about its central portion mounted on said pin Within the cavity adjacent the lower side of the head and being of sufficiently reduced length to leave the restricted opening unobstructed, and a metal filling cast into said cavity to fill the remaining interior space, the buckled portion of the sleeve being of greater diameter than that of the restricted opening in the cavity.

'-3. In combination, an electric insulator having a cavity therein provided With a restr icted opening, a pin extending through. Y said opening and into the cavity, a head on the end of the pin within thecavity having a lower face substantially at right angles to the axis of the pin, a one piece sleeve of continuous periphery buckled outwardly about

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