To all whom it may concern:

Be it known that we, FRANCIS H. SODEN and HENRY GOEHST, both citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Insulating Joints for Electric Lamps, of which the following is a specification.

The principal objects of our improvement are simplicity, strength, and durability, and the provision in a suspended electric lamp fixture of a desirable and efficient joint which shall not be liable to break in case the lamp is suddenly struck or pushed and which in the event of breakage shall still hold the lamp in a suspended condition.

To the attainment of the forgoing and other useful ends our invention consists in matters hereinafter described, and particularly pointed out in the claims.

In carrying out our invention we employ an insulator consisting of a block or ball composed of any suitable insulating material.  This insulator is adapted for engagement with and is engaged by both of a pair of interlocking loops.   The insulator is partially embraced at opposite sides by two loops, and is held between the points where the two loops intersect one another.  The loops are kept by the insulator with the respective planes at right angles , or substantially at right angles, to one another, whereby the possibility of  one loop coming into electrical connection with the other is avoided.  The upper one of the two loops is adapted to couple with a fixture--  such as a short neck permanently secured in the wall overhead, or a step depending from some fixed point—while the lower loop is adapted, as hereinafter set forth, to couple with a lower portion or section of the suspended lamp-fixture.  The joint thus formed may be made more or less yielding, according to the extent to which the loops are made to clasp or embrace the insulator, it being observed, however, that in all cases the joint in the event of the lamp being suddenly struck or pushed.  Should the insulator become broken by any unforeseen accident, the loops will be left interlocking with one another, and the lamp will thereby be prevented from dropping and breaking.

In the drawings, Figure 1 represents in elevation an insulating-joint in a suspended electric-lamp fixture embodying the principles of our invention.  Fig. 2 is a central vertical section taken through the device of Fig. 1.  Fig. 3 represents our insulating-joint with means of varying the grasp or clamping force of one of the loops upon the insulator.  Fig. 4 is a central vertical section through the device of Fig. 3.  Fig. 5 represents one of the loops preparatory to its application to the insulator.  Fig. 6 represents the insulator detached from the joint.

The preferred form of the insulator A is spherical, although for some purposes it could be somewhat differently shaped.  Thus it might be made either in the form of an oblate of a prolate spheroid, or it could be made of a polygonal shape.  The spherical form herein shown is, however, particularly applicable to its service in a joint for the fixture of an electric lamp, in order that the joint may the more readily be made yielding, so that in the case of a suspended lamp, should the lamp be struck or pushed, it will yield to the blow, but also permit the position of the lamp to be shifted.

In the several figures of the drawings, B denotes one, and C the other, of the two links or loops by and between which the insulator is held.

In order to permit the loops to effectively engage the insulator, and to prevent the loops from slipping off the insulator when the latter is spherical, as well as to keep the loops, when employed in a suspended lamp-fixture, from turning in a manner to come in contact with one another, the insulator is provided with the circumferentially-arranged grooves a, one for each loop.  These grooves may extend either partially or entirely around the insulator, it being preferable to provide the spherical form of insulator that is desirably employed in a joint for an electric lamp with two circumferentially-arranged grooves which extend entirely around the spherical insulator and respectively lie in planes at right angles to one another.   Portions of the loops are received in the aforesaid grooves of the insulator, which said grooves while herein formed by channels in the insulator are obviously the same in effect as though they were formed by parallel ribs or projections.

The loops or links may be formed and arranged to interlock and applied to the insulator in various ways.  Thus, for example, the loops can be arranged to pass through or interlock with one another by previously dividing one loop and substantially welding or otherwise mechanically fastening it together at such point, which mode is to be adopted in case the shank portions of the loops are not split or divided longitudinally; but either or both loops can be

formed of a piece of wire or other metal strip or piece bent into loop shape, so as to provide it with a divided shank, in which case the loops can be interlocked by opening the shank of one loop, so as to permit the eye portion of the other loop to pass into the loop that is thus opened.

The loops B are herein represented as being in one piece, and in Figs. 1 and 2 the loops C have a like construction.  In Figs. 3 and 4, however, the loops C are each formed by a piece bent to provide the loop with a divided shank portion.

In order to apply a link or loop, B, to the insulator, such loop may be first made substantially as in Fig. 5, wherein the eye or circular opening of the loop is adapted to receive the spherical insulator, and also desirably made somewhat oblong or egg-shaped.  Such loop can be first passed upon the insulator, and the loop then pinched so as to contact a portion of the loop in one of the circumferential grooves of the insulator, as best illustrated in the sectional view, Fig. 2.  Where a loop, C, made in one piece, has been previously made to pass through such loop B, the said loop C may likewise have been shaped similarly to the loop in Fig, 2 and applied to the insulator in the same way.  When the loops are applied as in Figs. 1 and 2, each loop embraces about one-half the circumference of the spherical insulator, with the sides of the loop beyond their points of contact with the insulator somewhat contracted, thereby holding the insulator, but providing a yielding joint in case the loops are not compressed too tightly upon the insulator, it being obvious that the joint thus formed is susceptible of action similar to an ordinary universal joint or ball-and-socket joint.

In Figs. 3 and 4 the shanks or stem portions of the links or loops C are shown divided, with the two part stem of each of said loops threaded sp as to permit a nut, D, to be screwed thereon for the purpose of tightening the loop upon the insulator.  This arrangement will be found desirable in several instances—for example, where the joint is to be used in the side bracket for an electric lamp.

The loops B are herein shown provided with threaded sockets b, whereby they can be readily attached to a permanent fixture—as, for example, to the threaded nipple usually arranged at the center of the ceiling of a room and commonly known as an “outlet;” but of course any other suitable mechanical fastening device could be substituted for the threaded socket, or the socket, if used, could be connected with any desirable fixture.

In Figs. 1 and 2 the loops C are provided with threaded sockets c, similar to the sockets of the loops B.  These threaded sockets are shown connected with tubes or tubular rods E, which form the lower or outer section of a suspended lamp—that is to say, the outer section, in case the lamp is suspended as a side fixture, or, what is substantially the same thing, the lower section on a hanging, it being understood that the tubular rod E in said figures is to represent a portion of the stem of the lamp.  In such case the conductors G and G’ can be carried up through the tube E and past the joint, the stem or shank of the loop C being provided with a central passage, c’, for the conductors.   Should the insulator, from any unforeseen cause, become broken so as to crumble or drop out of the joint, the lower loop, C, will still be left interlocking with the upper loop, B, and hence the lamp will be kept from falling to the floor.

In Fig. 4 the tube F is provided with a lateral opening, c, for the passage of the conductors G G’, which said lateral opening can, if desired, take the place of the passage c’ through the loop-stem in Fig. 2.

By means of the foregoing construction we provide an insulating-joint which may be made more or less yielding or flexible, as desired, and effectively insulate the loop or member B of the joint from the opposite loop or member, C.  Should either or both of the wires become electrically connected with the loop C, the integrity of the joint as an insulator between such loop and the ground will still be preserved.

What we claim as our invention is—

In a joint for a suspended electric lamp, the combination, with an insulating-body, substantially as described, of the loop B, having a stem provided with a socket for coupling it to a fixture, and the loop C, having a stem adapted substantially as described, for coupling it with the lower section of the suspended lamp-stem, said insulating body being held by and between the loops in an electric-lamp fixture, substantially and for the purposes set forth.

FRANCOS H. SODEN.

HENRY GOEHST.

Witnesses:

        CHAS. G. PAGE,

        L.S. LOGAN.