To all whom it may concern:

Be it known that I, JOHN J. IRWIN, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Insulators, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention relates to an improved insulator for supporting telephone and telegraph wires or other like electrical conductors, and is of the class known to the trade as the "saddle-top" insulator, that is, of the sort having a transverse groove in its top within which the line wire rests, in contra-distinction to a very common form of insulator having a circumferential groove for the retention of a tie wire by which the line wire is lashed to the side of the insulator.

The numerous advantages of a properly designed saddle-top insulator over that having only the circumferential groove such as its facilitating the removal of slack from a comparatively long stretch of wire, and its expediting the construction of the line, because of its ability to support the line wire in a well insulated condition even in the absence of tie wire are well known and thoroughly appreciated by persons familiar with the general subject of "line wire support"; but, in the use of all saddle-top insulators with which I am familiar the difficulties are experienced of the insulators breaking due to the strains imposed upon them by the line wire by reason of their improper design, and of the breaking of the line wire because of the distortion to which it is subjected by the wire-holding or engaging parts of the insulators.

In all insulators of the class to which my improvements belong (as well as in the insulators of the circumferential groove type), tie wires or their equivalents are required for holding the line wire against displacement.  The conditions sought for and which should exist in an insulator are these:  The insulator should support the line wire practically without the need (so far as the support is concerned) of ties and without imposing upon the line wire any biting, bending or straining effect other than results from the weight of the wire; and the tie wire should fulfill its function of holding the line wire against displacement without kinking or pinching the wire or in any way injuring it.

It is the object of my invention to provide, at no greater expense of production than in the case of insulators of the prevailing type, an insulator possessing the desirable qualities above mentioned, and having associated with it (in a more limited phase of the invention) a tie wire of peculiar formation that will effectually hold the line wire against displacement without damaging it.

To this end my invention consists in producing an electric wire supporting and insulating device having the characteristics set out in the claims annexed hereto and specifically described hereinafter by reference to the accompanying drawing which forms a part hereof, and wherein Figure 1 is a perspective view of my improved insulator in use; Fig. 2 is a section through the insulator in the vertical plane of the line wire; and Fig. 3 is a fragmentary vertical section at right angles to Fig. 2.

The body portion 1 of the insulator is provided with the usual threaded socket 2 for the reception of the threaded upper end of a peg 3 which may be carried by a cross arm 4.  The upper end of the body portion is enlarged to form a crown 5, the periphery of which overhangs the adjacent part of the body portion in order to produce a downwardly facing circumferential ledge or shoulder 6.

A transverse groove 10 is formed in the top of the insulator, and the bottom of this groove, which is shown as straight, is spaced below the plane of the shoulder 6 a distance substantially equal to the combined diameters or thicknesses of the line wire and the tie wire, for an important reason which will be explained hereinafter. I do not consider it so essential that the bottom of the groove 10 be absolutely straight, but it is important that the portion whereon the line wire rests is spaced the aforesaid distance below the plane of the ledge.

The line wire, which is represented at 12, lies upon the bottom of the groove 10, and the central portion of a tie wire 13 is passed about the insulator body in contact with the shoulder or ledge 6 and above the line wire.

Upon one side of the insulator body the tie wire is crossed as indicated at 14, and is then carried backward on each side of the insulator and beneath the line wire where its ends are twisted spirally about the line wire in both directions from the insulator the extreme end portions of the tie wire being turned backward upon themselves.

It will be observed that the space between the line wire and the ledge

or shoulder is ample to receive the tie wire so that the tie wire does not exert any pressure upon the line wire, and it will be explained that the end portions of the tie wire are twisted about the line wire in such a manner as to avoid any possible injury to the line wire especially in hard drawn copper wire which is practically exclusively used in telegraph work, any kinking, pinching or undo bending of the wire, particularly if it is sufficient to break the surface of the wire greatly impairs the strength of the wire and is likely to result in the wires breaking For this reason the insulator should support the line wire straight and free from kinks or bends under all circumstances whether the wire is covered with ice, snow or other weighty matter, or is free from such encumbrances.  This result is assured in the use of my improved insulator.

While it is essential that the line wire be supported far enough below the shoulder or ledge 6 to permit the tie wire to be received between them without its exerting any pressure upon either, it is fully as important that no more space be left between the ledge and line wire than is required to attain this end, for if there were, the line wire would lie free to move with the result that it would be chafed by rubbing against the sides or bottom of the groove and against the tie wire, and thus injured, or the tie wire would become weakened by the vibration of its end portions. Therefore the proportions herein set forth constitute the essence of my invention.

Having thus described my invention what I claim is:

1. An insulator comprising a body portion having a downwardly facing ledge adapted to be engaged by a tie wire, and having also a transverse groove for the reception of a line wire, the bottom of the groove being spaced below the plane of the ledge a distance substantially equal to the combined thicknesses of the tie wire and line wire.

2. An insulator comprising a body portion having a circumferential downwardly facing ledge that is adapted to be engaged by a tie wire, and having also a transverse groove for the reception of a line wire the bottom whereof is straight and spaced below the plane of the aforesaid ledge a distance substantially equal to the combined thicknesses of the tie wire and line wire.

3. An insulator comprising a body portion which terminates at its upper end in an enlarged crown the periphery of which overhangs the adjacent end of the body portion to form a downwardly facing ledge that is adapted to be engaged by a tie wire, the body portion being provided with a transverse groove which extends downward through the crown and has a straight bottom upon which a line wire is adapted to rest and which is spaced below the plane of the aforesaid ledge a distance substantially equal to the combined thicknesses of the tie wire and line wire.

4. In a wire supporting device of the character set forth, the combination of an insulator body having a circumferential downwardly facing ledge that is adapted to be engaged by a tie wire, and having also a transverse groove in its upper end for the reception of a line wire, the wire supporting portion of the groove being spaced below said ledge a distance substantially equal to the combined thicknesses of the tie wire and line wire and a tie wire which passes about the body above the line wire and in engagement with the ledge thereby to maintain the line wire in contact with the wire supporting portion of the groove.

5. In a wire supporting device of the character set forth, the combination of an insulator body having a circumferential downwardly facing ledge that is adapted to be engaged by a tie wire, and having also a transverse groove in its upper end for the reception of a line wire, the bottom of the groove being spaced below said ledge a distance substantially equal to: the combined thicknesses of the tie wire and line wire, and a tie wire which passes about the body above the line wire and in engagement with the ledge and is crossed over itself on one side of the body and continues about the same in both directions to where its opposite ends are twisted spirally about the line wire and away from the insulator in such condition as to permit the line wire to remain undistorted by the insulator or tie wire.

6. An insulator comprising a body portion having a downwardly facing ledge adapted to be engaged by a tie wire, and having also a transverse groove for the reception of a line wire, the wire supporting portion of the groove being spaced below the plane of the ledge a distance substantially equal to the combined thicknesses of the tie wire and line wire.

In testimony whereof, I hereunto affix my signature.

     JOHN J. IRWIN.