US2224960A

US2224960A - Device for securing electric

Info

Publication number: US2224960A
Authority: US
Publication date: 1940-12-17
Anticipated expiration: 1957-12-17

Description

G. HAOUR Dec. 17, 1940.

DEVICE, FOR SECURING ELECTRIC CONDUCTORS TO AN INSULATOR Filed Aug. 6, 1958 2 Sheets-Sheet 1 G. HAOUR Dec. 17, 1940.

DEVICE FOR SECURING ELECTRIC CONDUCTORS TO AN INSULATOR Filed Aug. 6, 1958 2 Sheets-Sheet 2 Patented Dec. 17, 1940 PATENT OFFICE DEVICE FOR SECURING ELECTRIC CONDUCTORS TO AN INSULATOR Georges Haour, Alger, Algeria, assignor to Societe Algerienne dEclairage et de Force, Alger,

Algeria Application August 6, 1938, Serial No. 223,428 In France August 11, 1937 5 Claims.

In the present construction of overhead electric lines, each of the two continuous sections of each electric wire, situated on either side of a supporting insulator, is connected with this insulator by binding. When the two sections are in position, the stresses which they exert upon the insulator are usually in equilibrium, and thus the tower or post carrying this insulator will not be subjected practically to any lateral stress, as the resultant of the tractive forces exerted in contrary directions by. the two sections are vertical, or practically vertical. However, such is not always the case, and chiefly if one of the sections should break. The tower or post is then subjected to a great lateral stress due to the traction of the section which is not broken. The abnormal and unsymmetrical stress to which the tower or post is subjected may be sufiicient to cause damage to the same.

The present invention has for its object a device for the removable securing a conductor to an insulator, by which the serious drawback above mentioned is obviated. The said device is chiefly characterized by the fact that it is so constructed that in the case of an abnormal strain upon either of the two sections situated on the respective sides of the insulator, the connection between the said sections and the insulator can be automatically broken, thus allowing, for the said conductor, a longitudinal movement in the direction of the said abnormal strain, which is no longer imparted to the insulator. The said device comprises a cap-piece which can be secured to the upper part of the insulator, and comprises two cheeks which are parallel to the axis of the conductor, and whose upper edges comprise oblique surfaces which support suitable stops secured to the conductor.

In one embodiment, the said oblique surfaces form, on each cheek of the cap-piece, a deep notch having the form of a V, in each of which is engaged an axle or journal mountedon a wireclamp which is placed upon the conductor.

In another embodiment, the oblique surfaces of each cheek of the cap-piece form a projection having the shape of an inverted V, i. e., with its vertex upwardly directed, and this projection is located between two axles or journals pertaining to two respective wire-clamps secured to the conductor, on which a weak point can be formed between these two wire-clamps. The advantage of this weak point is that the breakage of the conductor under an abnormal stress will take place at this point, and hence this breakage will offer a less drawback, and chiefly for supports which are not provided with cap-pieces with sliding attaching parts. Another advantage of this weak point is that the conductors can be used over again after the breakage, if the reduced section has been determined in such way that in their normal cross-section, the conductors have not exceeded their elastic limit.

Preferably, the lateral edges of the two cheeks of the cap-piece come nearer together towards the top, and thus in the case of breakage of one of the sections or strands of the conductor after an abnormal strain upon this section which has brought the axles of the wire-clamp, or of one of such clamps, against the corresponding lateral face, the second section can escape after such breakage of the first section.

In the accompanying drawings, which are given solely by way of example:

Fig. 1 is a side View of a device according to the invention.

Fig. 2 is a front view of the same.

Figs. 3 and 4 are two diagrams showing the advantage obtained by the lateral oblique faces of the cheeks.

Fig. 5 is a side view of a modification with inverted V-shaped parts.

Fig. 6 is a corresponding front View.

In the embodiment shown in Figs. 1 and 2, the

device comprises a cap-piece l, preferably of metal, which is secured to the insulator 2 by sealing at 3 (it should be noted that the cap-piece can be secured to the insulator in any other manner, for instance by means of a collar).

The cap-piece l essentially comprises two cheeks 4 and 5 which have the parallel position and are parallel to the electric line wire. Each of the checks 4 and 5 forms at the top part a V-shaped notch bcd, whose point is downwardly directed. The V-shaped notches of the two cheeks have the opposite position. The lateral faces ab and de of each cheek are oblique, and proceed, at the top, towards the transverse plane of symmetry XX.

At the point adjacent the cap-piece i, the wire 6 is held in a wire-clamp consisting of two jaws l and 8, which are pressed against the wire by a strap 9 which passes through a transverse block l0, and which carries two clamping nuts I l. The block I0 is provided at each end with a journal [2 whose axis YY is horizontal and is perpendicular to the longitudinal axis ZZ of the wire 6.

The operation is as follows. In normal conditions, the wire clamp rests, by the ends of its journals I2, in the lower parts of the two V- shaped notches bed of the cap-piece I.

arrows f and f owing to a slight difference between the forces of. traction in opposite directions which are exerted upon the two sections of the wire situated on the respective sides of the wire clamp in two successive spans of the electric line,

-a resistance which is sufficient to prevent the wire-clamp from leaving the cap-piece. the case of an excessive force, and chiefly in the case of breakage of one of the two, sections of the wire, the sides be and cd will no longer prevent the movement of the journals l2 resulting from the traction of the wire which is not broken.

The sides ab and de, situated on either side of the V-shaped part, on the checks 4 and 5 of the cap-piece l, are inclined (Figs. 2 and 4), and serve to prevent the lateral holding of the wireclamp against the cap-shaped piece I, in the case in which the wire-clamp has left the V-shaped parts bcd for any fortuitous cause and is now urged in the opposite direction.

In fact, Fig. 3 shows that if the faces a'b and de' were vertical, (the wire-clamp would become jammed at p against the cheeks if the breakage of the section mn should take place after a first displacement in the direction of the arrow f by the action of this section and thus by the subsequent traction of the secton no in the direction I the cap-piece I would be subjected, in-the direction I to a great force, which might cause the overturning of the post or tower carrying the insulator with its cap-piece. But with the in clined faces ab and de (Fig. 4) the wire-clamp, which has now come to the point p by the action of the section nm is enabled, after thebreakage of the said section nm, to rise under the action 40 of the section no and may even escape at d, in

certain cases, if the traction exerted by the section no becomes excessive.

Such effects may occur, especially with a line covered with frost, owing to the difference in the 5 traction due to the deposit of frost upon one of the two sections (nm for instance) without break-age of the wire. In this case, the cap piece, will move in adireotion (arrow f for instance) contrary to that of the span no which is not 50 frosted. If the breakage of the wire shouldgthen occur on the side of the support towards which the cap-piece has slid (in the section nm), the

cap-piecewill be abruptly drawn in the direction of f contrary to its first movement. At this 55 time, asabove stated, one of the sides (abfor instance) of the checks 4 and 5 of the cap-piece I, will enable the wire clamp to slide upon it.

Figs. 5 and 6 show a modification, in which the V-shaped notch of each cheek 4' or 5 of the 60 cap-piece I represented in the preceding construction is replaced by a projecting part having the form of an inverted V; the lateral faces ab" andd"e' are oblique, as before, and are connected with the sides b'c' and c'd by two 55 horizontal parts b"b and d"d, which support the journals l2 and I2 of two wire-clamps 1 8 and 1 8 of the above-mentioned type, which are pressed upon the conductor 6.

It will be at once observed that in the case of 70 an abnormal strain upon one section of the wire,

'75 ing V-shaped notches, the'sides b'c' and c'd' of But in the cheeks of the'cap-piece, upon which the two wire-clamps rest by the ends 'of their journals, will have a suflicient slope to prevent the movement of the said clamps, and hence of the wire, when the longitudinal strains of the two sections of the wire do not exceed the normal value, and to allow this movement when such strains are abnormal. The fact which, as-to its utilization, constitutes the difference between the cap-piece with projections having the form of an inverted V and the cap-piece having'V-shaped notches, is that the first of these will allow of providing, between. the two wire-clamps, at the point q (Fig. 6) a weak point in the wire 6' analogous to a mechanical fuse, thus permitting the breakage of the wire when the stress exceeds a. given value. r

This weak point is obtained by reducing the cross-section of the wire at this point.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1-. A device for attaching an electric conductor to an insulator which comprises a cap piece adapted to be secured to the top of the insulator and provided with two parallel cheeks, the outline of each cheek having at least one substantially horizontal bearing portion and on at least one side of said bearing portion and in succession two portions inclined in contrary directions and converging to an upper edge located higher than said horizontal bearing portion, the; inclined'portion adjacent said horizontal portion merging in said horizontal portion, a pin disposed at right angles to said cheeks and resting normally on the horizontal bearing portion of :both cheeks, clamping means adapted to receive said electric conductor, and connecting means connecting said clamping means to said pin, whereby said pin is adapted to slide on the inclined portion of each cheek adjacent said bearing portion and to rest on the other inclined portion under an abnormal stress directed towards said one side of said bearing portion and to slide again successively on said inclined portions towards said bearing portion under another stress having an opposite direction to the first stress.

2. A device for attaching an electric conductor to an insulator which comprises a cap piece adapted to be secured to the top of the insulator and provided with two parallel cheeks, the outline .of each cheek having two substantially horizontal bearing portions at the same level and at a distance from each other and between said bearing portions two portions inclined in contrary directions and converging to an upper edge located higher than said horizontal bearing portions, each inclined portion merging in the adjacent' horizontal bearing portion, two pins disposed at right anglesto said cheeks and resting normally on the horizontal bearing portion of both cheeks respectively on either side of said inclined portions, two clamping means adapted to receive said electric conductor, andconnecting means connecting said two clamping means respectively to said two pins, whereby each pin is adapted to slide on the adjacent inclined portion and to rest on the other inclined portion under an abnormal stress directed towards the other pin and to slide again on said inclined portions towards its initial position under another stress adapted to be secured to the top of the insulator and provided with two parallel cheeks, the outline of each cheek having two substantially horizontal bearing portions at the same level and at a distance from each other and on either side of each horizontal bearing portion two inclined portions merging in said horizontal bearing portion, the inclined portions adjacent one horizontal bearing portion being inclined in a contrary direction to that of the inclined portions adjacent the other horizontal bearing portion and the two inclined portions situated between said horizontal bearing portions converging to an edge located between said horizontal bearing portions, two pins disposed at right angles to said cheeks and resting normally on the horizontal bearing portion of both cheeks respectively on either side of said edge, two clamping means adapted to receive said electric conductor, and connecting means connecting said two clamping means respectively to said two pins.

4. In combination an insulator, a cap piece adapted to be secured to the top of said insulator and provided with two parallel cheeks, the outline of each cheek having two substantially horizontal bearing portions at the same level and at a distance from each other and on either side of each horizontal bearing portion two inclined portions merging in said horizontal portion, the inclined portions adjacent one horizontal bearing portion being inclined in a contrary direction to that of the inclined portions adjacent the other horizontal bearing portion and the two inclined portions situated between said horizontal bearing portions converging to an edge located between said horizontal bearing portions, two pins disposed at right angles to said cheeks and resting normally on the horizontal bearing portion of both cheeks respectively on either side of said edge, an electric conductor having a weak point, two clamping means receiving said electric conductor respectively on either side of said Weak point, and connecting means connecting said two clamping means respectively to said two pins.

5. A device for attaching an electric conductor to an insulator which comprises a cap piece adapted to be secured to the top of the insulator and provided with two parallel cheeks, the outline of each cheek having one substantially horizontal bearing portion and on each side of said bearing portion and in succession two portions inclined in contrary directions and converging to an upper edge located higher than said horizontal bearing portion, the inclined portions a-djacent said horizontal portion merging in said horizontal portion, a pin disposed at right angles to said cheeks and resting normally on the hori zontal bearing portion of both cheeks, clamping means adapted to receive said electric conductor, and connecting means connect'mg said clamping means to said pin.

GEORGES HAOUR.