US2864161A - Squeeze connector - Google Patents

Description

Dec. 16, 1958 L. M. CURTISS 2,864,161

SQUEEZE CONNECTOR Filed May 27, 1953 QTTORNEY United States Patent SQUEEZE CONNECTOR Lawrence M. Curtiss, Mountainside, N. J., assignor to The Thomas 8; Betts Co., Elizabeth, N. J., a corporation of New Jersey Applicafion May 27, 1953, Serial No. 357,699

1 Claim. (Cl. 29505) The invention relates in general to an electric connector for securing a cable to a wall at an opening therein, and specifically relates to a connector for securing a cable conductor in a knock-out opening in an outlet or junction box and for positively and permanently locking the assembly of connector and cable conductor to the wall of an outlet box at one of its knock-out openings.

It has been known in this art as described in the patent to Namet, No. 2,527,227, October 24, 1950, to provide a thin metal connector with a body portion provided at one end with a preformed abutment for engaging one side of the wall of said outlet box adjacent a knock-out opening and whose other fluted end extends through said knock-out opening. By transversely directed squeeze pressure thereon the fluted end of the connector is deformed radially at one part thereof to distend some of the flutes inwardly into crimped engagement with a cable therein and at another part the opposing flutes are distended radially outwardly to form rounded abutments intended to coact with the first-named abutment to secure the connector to the outlet box.

This manner of securing the connector to the box Wall is objectionable in that the rounded abutments so formed actually provide easily collapsible stops, and in practice a pull on the cable in the direction of the preformed abutment tends, as the rounded abutments are wedged against the edges of the box hole, to collapse the rounded abutments inwardly back towards their initial positions, with the result that either the connector as a whole is displaced from the knock-out hole or at least there results a loosening of the connector therein.

With reference to other objections to this known form of connector, it may be noted that this fluted form requires the use of a specially formed crimping tool to fit the flutes, in order to form the rounded abutments. Also, in the process of crimping the connector the flutes at their inner edges tend to bite inwardly through the insulation on the cable, with the result that an objectionable electric leakage is quite apt to occur between the cable conductor and the connector.

The primary object of the invention when considered in its simplest form is to provide a positive form of interlock between the connector and the box wall at its knockout opening and thus defeat possibility of accidental withdrawal or loosening of the connector from the outlet box by reason of any axially directed load on the connector.

In this specification the term positive lock" or slot and key type of fastener is intended to cover a structure like a door lock, where a key or latch element is intruded into a slot or recess in a keeper and wherein the slot or recess is provided with a square shoulder or wall opera tive to avoid the escape of the key or latch element laterally from the slot or recess.

Another object of the invention is to provide a form of connector which can be installed in position in the outlet box and crimped onto its contained cable, and at the Patented Dec. 16, 1958 ICC same time permanently lock the connector to the box I with a pinching action, say, with a pair of ordinary pliers,

is an objective of the invention to absorb pull loads on the cable, which loads might otherwise tend to loosen the engagement of the connector with the box wall.

Still another object of the invention is to provide a cushioning layer of resilient and insulating material between the cable and the metal connector to absorb strains on the cable and thus'prevent, or at least tend to prevent, their transference to the metal connector while locked to the outlet box as herein featured.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of two forms of connector embodying the invention, and the invention also consists in certain new and novel features of construction and combination and arrangement of parts hereinafter set forth and claimed.

In the accompanying drawings Fig. 1 is a perspective view of connector constituting an article of manufacture forming a preferred embodiment of the simpler form of the invention;

Fig. 2 is a vertical sectional view taken axially of Fig. l in position'loose in a knock-out hole of an outlet box prior to the insertion of the cable therein;

Figs. 3 and 4 are explanatory views, with Fig. 3 taken on the line 3-3 of Fig. 2, and Fig. 4 taken on the line 4--4 when the connector is crimped to its elliptical form;

Fig. 5 is a longitudinal sectional view of the connector when crimped to a cable therein and locked to a wall of the outlet box;

Figs. 6 and 7 are each transverse sectional views taken, respectively, on the lines 66 and 77 of Fig. 5;

Fig. 8 is an enlarged detail view of the positive interlock shown at the top of Fig. 5, without the cable;

Figs. 9-12 disclose the form of the invention featuring the strain-relief conductor, and wherein Fig. 9 is an axial sectional view of a preferred form ofthis type of connector as it exists as an article of manufacture; Fig. 10 is an elevational view of the right end of Fig. 9, showing a two-wire cable fitted in its elliptical bore as it exists before the connector is squeezed into its crimped position; Fig. 11 is a view in side elevation of the relief connector of Figs. 9 and 10 shown in position locked to a wall of an outlet box and crimped onto a cable therein; and Fig. 12 is a transverse sectional view taken on the line 12-12 of Fig. 11 and with parts broken away to show internal constructions.

Referring first to the simpler form of the invention as disclosed in Figs. 1-8, there is disclosed in Figs. 1-3, a one-piece connector 13 of thin sheet metal, preferably a form of soft steel, formed in one stamping operation on an eyelet machine. The connector includes a cylindrical body portion 14 provided at one end with an integral outstanding annular flange 15. The disclosure particularly features a plurality of suitable openings 16 punched through the body portion 14, in angular spaced relation and extending in line in a plane parallel to and located in close proximity to the flange 15. In the case illustrated there is disclosed six openings arranged in three pairs of two each in relatively diametrical relation. With this arrangement the formation of diametrically opposite projections on the body portion 14, is assured whereby to secure the connector in the knock-out opening -A in the outlet box irrespective of where the squeeze is had, .as hereinafter described.

The body portion 14, is dimensioned to fit rather snugly in a knock-out opening A in the wall B of a conventional outlet box. The box opening is outlined by a sharp metal edge C, circular in form.

The openings 16 in the body of the connector 13 are located in close proximity to the flange 15, and are of such predetermined size or diameter that when the flange 15 thereof is in contacting engagement with the inner face ofthe wall B of the outlet box, a portion of thedefining edges of the openings 16 willextend outwardly of the outer face of the wall B, as clearly shown in Fig. 2.

In the process of imparting an elliptical configuration to the extended body portion 14 of the connector, as indicated at 14a in Figs. 7 and 8, the defining edge portion of each ofa pair of oppositely disposed openings 16, is partially folded upon itself to form a substantially semicircular notch therein for receiving the defining edge portion C of a knock-out opening A in-the bottom thereof with the outer portion of each notch forming an inclined shoulder substantially in abutment with the outer defining edge portion of the knock-out opening A in the wall B of the outlet box, whereby the connector 13 is securely retained in said knock-out opening A. It is particularly noted that the bore 17 of the connector as initially formed is cylindrical and is wide open and free of anything WI'IIJiICh might interfere with the insertion therein of 21 ca e.

With the connector in place as indicated in Fig. 2 a cable D is inserted extending through and beyond the bore 17 of the body 14 as is usual in such devices.

The cable illustrated is of a type commonly used with outl t boxes and may comprise a single insulated cable enclosing one or more conductors or two insulated cables E, each including a central conductor F, with the two cables each wrapped in an outer layer G of insulating material.

The body portion 14 in the part exteriorly of the box wall and immediately beyond the openings 16 therein is subjected to a squeeze pressure as by means of a pair of jaws H and I of a pair of ordinary hand pliers shown in ghost outline in Fig. 4. In doing this some care is exercised to see that the line of squeeze pressure S-P be at least approximately at right angles to a transverse line such as is shown at a-b in Fig. 4, connecting a pair of the opposed openings 16. This action has the effect of deforming the body portion 14 from its circular form in Fig. 3 to an elliptical form in Fig. 4 and intoa crimped and binding engagement with the cable contained therein, as shown in Fig. 7. At the same time the narrow ends of the ellipse 14:: so formed extend radially outwardly of the adjacent defining edge C of the knock-out opening A and locate the deformed openings 18 and 19 resulting therefrom, in engagement with the diametrically related portions of the defining edge C of the knock-out opening as shown in Figs. 7 and 8. It is noted that the outer ends 22 of the deformed openings 18 and 19 form two sloping shoulders which in their engagement with the outer face of the box wall B, provide stops which in their engagement with the wall prevent endwise movement of the connector as a whole relative to the box wall. In this way there is provided a positive form of non-releasable lock or, differently expressed, a key-and-slot form of fastener between.

the connector and the box wall. The opening 16 with the box edge C acting as a key intruding into the same as at 18 and 19 forms in effect two keeper slots in which the diametrically related portions of the edge C defining the knock-out openingA act as latch elements to form a positive lock of the keeper-and-latch type.

In the showing in Fig. 8 the edge 22 at the outer end of the deformed opening 18 is spaced slightly from the adjacent outer side of the wall B, but it is understood that the presence or absence of the intervening clearance is dependent upon the extent to which the body portion 14, is deformed into the ellipse 1412. Thus, with the flange 15 in abutment with the inner face of the wall B, and the deformed defining edge portions of the respective openings 18 and 19, in abutment with the outer face of the wall B, the connector 13 is retained against relative movement, in the knock-out opening A, with no possibility of the wall B acting to release the connection therebetween, in response to a pull on the cable D, as in the previously known form of such connectors.

Referring to the modified form of the invention shown in Figs. 9 to 12, there is disclosed the metal connector 13 above described, but with its body portion lined and the inner side of its flange faced with a complementary sleeve 23 formed of a resilient,.rubber-like insulating material. The rubber-like sleeve includes a body portion 24 of cylindrical form snugly fitted in the body portion 14 of the connector 13. and provided at one end with a complementary flange: 25 having'on its inner face a hollow recess 26 in which the flange 15 is fitted, so that the metallic connector with its sleeve lining becomes an integral article of manufacture, as shown in Fig. 9. It is suggestedithat the bore 27 through'the sleeve be elliptical in cross section as shown in Fig. 10, for example, in order to receive the two wire. cables D with at least an approximate fit, and in this way tends to minimize the mass of resilient material which is to be deformed into the ellipse shown in Fig. 12;

The strain-relief assembly thus formed is mounted in the outlet box opening and a cable threaded therethrough,

as previously described. The' assembly in the part thereof exteriorly of the outlet box is then squeezed as above outlined to distend the portion of the connector into the elliptical form shown in Fig. 12 with the defining edges of the openings 18 and 19, as deformed thereby located in abutment with the adjacent parts of the defining edge C, of the knock-out opening A, as previously described. The rubber-like sleeve 23 likewise takes the elliptical-in-crosssection form, as shown in Fig. 12, so that both wires of the cable are squeezed between the opposing long sides of the elliptical sleeve. In this case any pull loads on the cable are cushioned and absorbd by the resiliency of the sleeve 23 and are not transferred to the metal connector. In this way strains on the metal connector are avoided and any tendency of a pull on the cable to displace the connector from the box is further avoided.

Sometimes the cable is provided at its center with a bare groundwire I. The instant disclosure in both forms provides a convenient means for attaching such wire to the ground provided by the outlet box. For instance, a free end of the ground wire may be inserted between the flange 15'and the wall B of the metal outlet box prior to locking the connector in place, and as the connector is locked to the wall the ground wire will likewise be firmly clamped in place.

I claim:

In the art of locking a cylindrical sheet metal member in an opening in a wall, wherein the cylindrical member is dimensioned to have a sliding fit in the wall opening and is provided with a pair of diametrically related lock openings extending therethrough and dimensioned to receive the edge of the wall outlining the wall opening, the method which consists in inserting the cylindrical member into the Wall opening and locating the lock openings in the plane of the wall and then applying a squeeze pressure on opposite sides of the cylindrical member along alineof squeeze pressure-at right angles to a line connecting the lock openings to distend the portions of the member containing the lock openings radially outwardly into position to receive the defining edge portions of the wall opening within the deformed openings and to the wall.

References Cited in the file of this patent UNITED STATES PATENTS Dann Dec. 1, 1936 Selig June 21, 1938 Jaberg July 23, 1940 Andren et a1 'Mar. 10, 1942 Winkelmeyer Feb. 16, 1943 Hartman Mar. 30, 1948 Namet Oct. 24, 1950

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