US1778714A - Insulating bushing - Google Patents

Description

Oct. 21, 1930. M. J. CAFIERO INSULATING BUSHING Filed Aug. 21, 1928 Patented Oct. 21, 1930 LTZSJM .ruaramnm MICHAEL J. GAFIERO, OF BROOKLYN, NEW YORK INSULATING BUSHING Application filed August 21,

The present invention relates to the insulation and protection of electric wires or cables where they issue from conduits and the like, and the objects 01'' the present invention are to provide an insulating bushing or insulating end fitting for such wires, which will be of strong substantial construction and appearance, which can be readily applied and which will hold the conductor or conductors securely and properly insulated from the end of the conduit, and, in the case of multiple conductors properly separated and in desired arrangement relative to eachother. I

The drawing accompanying and forming part of this specification illustrates certain practical embodiments of the invention wherein the foregoing and other desirable objects are attained, but it should be under-.

stood that the structure may be modified as regards these disclosures without departure from the'true spirit and broad scope of the invention.

Fig. 1 is a broken side elevation and part vertical sectional view of the invention as embodied in a simple insulating bushing; Fig. 2 is a similar view of the invention as embodied in a conduit end fitting.

The body or shell of the bushing is shown as a short or shallow metallic collar 3 open at the top to receive and form a partial housing for the insulating portion of the device and as internally screw-threaded in its lower end at 4 to screw into position on the upper threaded end of the conduit 5. This collar is illustrated as of generally cylindrical external form and not much larger than the conduit so as to occupy but small space and be capable of use on conduits which may be set particularly close together. To facilitate the screwing of the collar in position on the conduit, the same is shown as having flutes or pockets 6 in the sides of the same to receive suitable driving tool.

The upper open end of the collar is indicated as having a smooth cylindrical bore 7 extending down to an inwardly projecting annular flange 8. This annular flange by abutment at its lower side against he end of the conduit serves to position and frictionally lock the shell on the upper end of the 192 Serial No. 301,

conduit and provides at its upper face a seat for the bushing 9 insu material.

The insulating n 9 's constructed in the form of a rel hat or shallow ring or disc having an extern 1 diameter to fit down into the cylindrical bore or shell and in some instances to seal or re shoulder provided by the inwardly enten flange 8.

In the case of what i known in the trade as an insulating bu shin g, the insulating member 9 consists of a fiat ring of insulating material fitting in the upper open end of the shell and having a single large opening 10 therethrough for the one or several cables or wires 11. This ring is shown as having an out wardly extending annular flange 12 at the upper end of the same resting upon and ova"- standing the upper end of the shell. so as to be supported by and to form an insulating guard over the upper end of the shell. This ring of insilatingg material is sui.ably anchored in its that it will not be displaced when the wires or cables are pulled out of the conduit as by means of drive pins 13 entered. through the sides of the shell into seats provided t edeuendent cylindrical skirt or body portion of the ring.

The annular flange 8 on which the insulating ring rests can be made qui e thin as tl I flange is turn d down into ab neutwith the end of the conduit and any weight on the insulating e; is thereby ransferred to the end oi the conduit. Th s the shell and insulating rinn: can be made quite flat or short so as to ta p but little room on the 85 end of the coudi nd go into small s aces where there hut l tle. room above and about the end oi th condui Pec use fur her of the small cunt ct mat insulation. the device produced quite inexpensivelr (nuan ed flange of the lTlFlllfi 'lfiQ rin may be of the same smooth neat appear nce and heing produced bv simple turn ng or tormine: pera ic 111 I the ca e an end t tsiinewhere th wires or cables are brought out to a ch panel, motor or the like. the c ustruction much the same as described. but. as indicated in Fig. 2, the insulating member is both metal and size cvlindrical turn"). presenting a many holes 1O therein as there are conduc tors so as to practically close up the end oi shoulder 8 in Fig. .2, or if the same construe the conduit about the conductors issuing therefrom. Also this disc may be made somewhat heavier and thicker and need not have the flange overstanding the end of the shell, being finished off for instance, the upper edge at let on a gradual curve down to substantially the inside diameter of the bore or seat in the shell.

To secure the end fitting disc in place. three equi-distantly spaced set screws 15 may be employed extending inwardly through the upper inner wall of the collar in engagement with an annular groove 16 about the lower skirt 1 portion of the insulating member. These set screws and the groove are relatively so placed that the co-operative eflect of the two will be to force the bushing firmly down to its seat in the shell. This feature is illustrated .at the left in Fig. 2, where the rounded point of one of these screws is shown as hearing against the inclined or bevelled lower wall of the groove. lVith this construction, it will be .seen that the pressure of the screws against this inclined shoulder will be etlective to force the insnlatingbushing member down into the shell and into firmly seated engagement with the supporting tion is employed in Fig. l, to force the insulating member into engagement with the lower shoulder .8 and the flange 12 into en V gagement with its seat on the end of the shell.

The firm seating of the insulating member provides practically a water-tight joint between this member and the shell and also when. the screws are setup firmly the insulati-ng member will be held against rotation in -the collar, which is an advantage where it is desired tohold the wires or cables in a predetermined relation, for instance, where they are led off to .a switch or other piece of electrical apparatus. The loosening of these screws permits the disc to be turned to position the conductors in any particular desired relation.

Another special feature ofthe thin flat ring or disc likememberis that the cable opening or openings therein is or are set radially inwardly beyond the inner edge of the flange 8, so as to guide and hold the cable or cablesaway :fnoniboth the. edge of this flange and the more or less sharp upper edge of the conduit. r

Instead of being previously shaped, the

insulating material may be molded into the insulating seat.

collar and thereby permanently locked in its To efl ect such permanent interlock,

the surfaces of the'collar against which the materialis molded-may bejleft 1 unfinished or 1n the rough, or if desired, an undercut may be formed 1n the inner wall molded will positively interlock with the collar.

What is claimed is:

1. An insulating bushing or end fitting structure for cable conduits, comprising a substantially cylindrical short shell of but relatively little larger diameter than the conduit to which it is to be applied, said short substantially cylindrical shell being internally screw-threaded in its lower end and more cable openings therethrough for-cables issuing from the conduit and disposed radially inward from the inner edge of the annular flange tothereby position and hold said cable or cabl s inwardly away fromthe edgegof said flange and from the end edge of'the conduit to which the device is'applied. ,b H V 2. m1 insulating bushing or end fitting structure for cable conduits, comprising a substantially cylindrical short metallic shell of butslightly larger diameter than the conduit to which it is-to be applied, said shell being internally screw-threaded in its lower end to directly engage the externally screw- 1 threaded :upper end of a conduit and having a thin inwardly projecting annularyflange at the upper-end of the screw threaded portion of approximately mid length of the col- 1 larto tornran abutment limiting the screwing of the collar :onto the conduit and sup ported by engagement with. the end of the conduit,-the upper end of the collar having an open cylindrical 'portion'above the annular flange .and of larger diameter than the screw threaded lower end portion of the collar and a body of insulating material seated onsaid annular flange within saidcyl-indrical upper ope-n endport-ion of the collar,

said body having a cable passage there- 1,

through disposed radially inwardly of the flange and of the upper edge of the conduit to whichthe collar is applied, saidinsulating body being fined against rotation in its seat in the collar. 1 V V In testimony whereof I and my signature; V 1 1 I J y BHCHAJEL J. OAFIERO.

of the collar, so that the material in being

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