US 2508476 A
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May 23, 1950 H. D. STECHER CABLE. CONNECTOR 2 Sheets-Sheet 1 Filed Sept. 19. 1947 INVENTOR. HENRY [2 5756/15/ 2 ATTORNEYS.
May 23, 1950 I s cH 2,508,476
' CABLE CQNNECTOR Filed Sept. 19, 1947 2 Sheets-Sheet 2 INVENTOR. HENRY D. 57'ECHER BY jw%7 ATTORNEYS.
Patented May 23, 1950 UNITED" S TATES. ATENT O F F [C E CABLE CONNECTOR Henry D.- Stecher, Lakewood, Ohio" Application September 19, 19437., SerialNo. 775N702 10 Claims. 1
Thls invention: relates to conduit connectors and more particularly: to improvements in BX conduit connectors which are adapted to secure and connect flexible armoredBX conduits or the like to terminal. or outlet. boxes or to perforate walls or plates:
An object of my inventionis to provide an improved connector in. which a single adjusting force or action causes. one part of the connector tocontract and rip a BX or like conduit and another'part to expandand grip within an apertured wall of an outlet box. Another object. is-
to-prov-ide aconnectorwhichisadapted to receive conduits of" various sizes andv bereceived in apertures of various sizes.v Another object is to provide: a connector which correctly positions the end of a BX conduit in placelwithin the connector and which presents a smooth rounded surface suitable for guiding the electrical leads from the.
conduit into the box without danger of abrading, cutting; or otherwise damaging the leads. Another objectisito provide azconnector in which conically disposed resilient fingers provide. abutting surfaces which position and hold the end of the conduit sheath and by their resilience enable accommodation of? the connector for use with conduits of varying size. A. turther objectis to. provide a connectorof wide range of adaptability which grips a BX or like conduit" and outlet loo-x tightly and firmly, which: is conveniently made from a single stamping, providing economy of" manufacture, which itselfv presents. no problem of assembly in manufacture-or use and which can. be easily and quickly assembled with a conduit, its conductors. and a terminal box.
Other objects include the provision of a B-X connector which" will securely engage the apertured wall ofan outlet box and. have" a positive engagement perpendicular thereto without tendency to wobble or tip and which will constrain the. conduit engagedby the connector to coaxial alignment therewith and desirable perpendicularity to said well. Another object is to provide aconnector in which the gripping action on the conduit and onthe aperturedwlall resulting from a single applied force is advantageously balancedand apportioned. Another object is to provide a connector through which conductors may be easily inserted and guided and in which the severed, often-jagged, end'of the: conduit sheath ist-secured an'dconstrained from deleterious contact: with the conductors or from hazardous-contact with: the fingers of the workman using the connector. Another: objectis to provide a con nector that is'ne'at and attractive-in appearance and which in operative engagement with a conduit and outlet box cleanly joins the twoand inhibits the intrusion of extraneous-material into Figure 2' is a top plan view of-' the connector of Figure 1; FigureS is a longitudinalsectional view of my connector taken inthe plane of the line 3 3 of Figure 2; Figure 4 is a longitudinal sectional view of my connector taken in the plane of the line t-- of Figure 2; Figures 5 and 6 are side elevations illustrating themode of operation. of my connector, and-Figure? is a plan view of the sheet metal blank from which my connector 1 is formed;
A preferred form of my connector, referred-to" generally at I, comprises a split cylindrical sleeve portion 2 formed from light gauge resilient sheet metal stock having an internal diameter larger than the largest conduit with which it is to be used and adapted upon expansion from its minimum external diameter to secure itself firmly within a hole H in the wall K of a terminal or outlet box. The sleeve 2 is provided internally with, crossed over conduit clamping elements or strap portions 3 and 4' which are adapted to be. contracted toward each other and to clamp the conduit C tightly between them. as the sleeve 2 is. expanded. The positioning of the conduit Within the connector preparatory tosuch clamping is facilitated by a plurality of bent resilient fingers- 5 which form a seating surface. for the end of the sheath of conduit 6 and which by reason, of their resilience help the clamping ele ments hold the conduit securely within, the sleeve when-it is expanded.
To facilitate expansion of the sleeve; 2' and the contraction of the clamping elements 3 and l; the sleeve is provided with a; pair of; outstanding radial wings 6 and 'l". A screw 8 threadedly extends through one wing t! and is adapted .to thrust against the other wing 1. When the; screw 8- isadvanced inwardly the wings: are forced.
apart, the sleeve is expanded within the hole H and'the' clamping elements are constricted upon the conduit; Whenthe screwisth-readedly withdrawn sothat the wings are no longer forced apart; the inherent resiliencyof the sleeve-preferably tend-s to contract it toits idle minimum exterior diameter and simultaneously expand the clamping elements to a wide open position.
The armored flexible conduit C is, as mentioned above, gripped in an advantageous manner at a point spaced from its extreme end by the clamping elements or straps 3 and 4 respectively. One element takes the form of a narrow strap or band 3, see Fig. 7, severed throughout its length from the upper edge of the sleeve and integrally joined to and bent away from the root of the wing t as at 9, then following the opposite side of the sleeve and around the conduit C (when the conduit is disposed therein as shown in Figure 2) for approximately half the circumference of the sleeve, and finally bending back to terminate in the wall of the sleeve at It, see Figures 2 and The other clamping element takes the form of a strap 4 cut from the wall of the sleeve at a level below the strap 3 and integrally joined to and bent away from the root of the wing l as at l l and following around the other half of the sleeve and the conduit C, the sleeve and the conduit C, finally bending back upon itself and terminating in the wall of the sleeve at i2, see Figures 2, 4 and '7.
. The clamping elements or straps 3 and i as best seen in Figures 2 and 3 hold the conduit C in the center of and concentric with the sleeve andthemselves are or become spaced from the wall of the sleeve as the sleeve is constricted. When the screw 3 spreads the wings 5 and l apart, the force exerted by the screw is trans-- mitted by the wings to the wall of the sleeve to expand it circumferentially and ipso facto to spread apart the points 9 and H which thereby draws the straps 3 and 4 toward each other to clamp the conduit forcibly between them. The constriction of contraction of the straps is thus simultaneous with the expansion of the sleeve and follows from the crossing of the straps in teriorly of the sleeve and their respective dispositions on opposite sides of the axis of the sleeve and conduit.
The circumferential and diametrical expansion of the sleeve causes it to be wedged tightly within the hole H in the wall of the box in which it fits. This expansion is such as to hold the connector firmly to the box, yet upon release of the screw 8 permits easy removal therefrom. Analysis of the manner in which the wings 6 and l and screw 8 impose and transmit force to the sleeve and clamping straps, will show that uniform displacement is not necessary over the longitudinal length of the sleeve but may vary depending on the conduit size, the diameter of the unexpanded sleeve and the diameter of the hole H. I prefer that the straps lie near the upper end of the sleeve, as viewed; that the opposite and lower end of the sleeve engage the hole H and that the screw 8 be disposed about midway between the ends whereby to apportion the hole and conduit gripping forces respectively about equally. If the diameter of the unexpandcd sleeve is only slightly smaller'than the hole H and the diameter of conduit C is about as small as can be conveniently used with the particular onnector, see Figure 5, then application of force with the screw will initially expand the sleeve Within hole H without bringing the straps into substantial clamping engagement with the conduit. Thereafter additional advance of the screw in the same direction will in part act to increase the gripping force between the sleeve and the periphery of the hole H but in greater part will distort the sleeve so that further expansion of the sleeve and corresponding constriction of the straps takes place large in relation to the size of the connector and the hole so that the clamping straps tend to engage the conduit before the sleeve is fully ex panded within the hole H, the connector will expand in the manner indicated ,infFigure 6, i. e., the initial turns of the screw 8 will result first v in a clamping of the conduit by the straps 3 and 4, the sleeve expanding but at first remaining loose in the hole H. After the conduit has been clamped further turns of the screw will distort the sleeve. so that expansion takes Place primarily at the bottom of the sleeve since the conduit pre'vents further contraction of the straps and the upper part of the sleeve. The screw then is turned until the bottom of the sleeve expands sufficiently to grip the wall of the hole H with satisfactory force. .Such ability to expand non-uniformly permits great flexibility of opera.- tion and enables my connector'to be used with a great variety of conduits and conduit boxes without any adjustment except that inherent in the mode of operation of my invention.
The resilient fingers 5, which as previously.
mentioned provide a seating surface for the end of the sheath of the conduit .0, see Figures 3 and 4, serve to restrict the longitudinally inward disposition of the conduit into the; connector, and the fingers 5 acting in cooperation with the clamping straps 3 and 4 hold the conduit concentrically and coaxially in place within the connector and normal to and 'coaxially of the hole H. The fingers 5 also participate in the adaptability of the connector to be used with a wide variety of conduit and hole sizes. The fingers preferably are turned upwardly from the bottom of the sleeve to lie interiorly thereof and are folded first slightly outwardly along the root line I3, Fig. 7, and then upwardly along the lines Na which lines are preferably spaced a slight distance from the roots of the fingers to form ears it, as best shown in Figures 1, 3 and 4. The fingers are folded again along their lateral center lines 55 at an obtuse angle; the fingers thus defining a conical passage H5 converging toward the in-- terior of the sleeve to a throat I? which is preferably smaller in diameter than the external diameter of the sheath of the smallest conduit to be used with the connector. From the throat ii the fingers. define a conically diverging passage l8 which merges into the interior surface of the sleeve in the mid-portion thereof. From the throat ll tothe ears is the fingers provide a smooth flaring mouth through which the conductors pass and are protected from deleterious contact with raw or sharp edges or corners. Preferably the portions of the fingers which define the passage It just above the throat H are slightly concave as at Hi to provide a seat or seating surface for the end of the sheath of the conduit. Preferably the fingers are resiliently stressed to tend to constrict the throat ll so that insertion of a conduit, cf. Figs. 3 and 4, will tend to expand the throat and the seating portions 19 affording a yielding grip between the latter and the end of the sheath. If later expansion of the sleeve incident to gripping the hole, H or the conduit by the crossed straps 3. and 4 increases or. tends to increase the'mean diameter of the upper. and lower ends of the fingers and hence thethroat H and seat l9 then the resiliency of the fingers."
will; continue the; desired center g embrace. and
contact with the end of the sheath.
The diverging passage l-6'- enables the wires W leading from the conduit. toenter the outletbox at: a substantial angle'without contacting or, bending around any sharp edges. danger of:- cutting or abrading. the wires-is substantially eliminated. If itshould be necessary to 24 and 25 which define clamping. strap 4, the
straps being bent at, the points 9, l and H, l2 respectively to the arcuate shapeadapted to conform to the conduit C as previously described, see Figure 2. The fingers are preferably slightly spaced apart at their root line l3, i. e., where they join the panel 2A, to facilitate their being bent upward into the sleeve. In order to, givetheseveral' fingers their collective hour glass form each of the fingers 5 is sheared to taper inwardly from its root and also from its free end to a reduced middle dimension corresponding to the throat at fold line 1-5. This general shape of fingers ensures that, when the fingers are bent and bent upwardly with respect to the panel 2A and the latter bent or rolled to. cylindrical form whereby the fingers form the tapering: passages, the width of the fingers at theseveral points of their length will not exceed the available minimum circumferential space nor occupy substantially less than such available minimum space.
The fingers being widest at the large open ends of the passages and being narrowest at the throat, the point of least circumference, the edges of the fingers will lie close together to define substantially continuous passage surfaces-whenthesleeve takes its minimum diameter and will not be inordinately or deleteriou'sly spacedwhen the sleeve is greatly expanded.
The dimension T of that strip of the main panel 2A which lies between the lower edges of the wings 6 and 7 and the root line l3 of the fingersas shown in Figure '7 is preferably slightlysmaller than the thickness of the wall K'of the conduit boxto-facilitate a snug grip between my connector and the periphery of the hole H as will presently more fully appear. Preferably a small triangular tang 28 is struck outwardly from the blank about midway between thewings 6 and l, as shown in Figures 4 and '7, and is adapted to be bent outwardly to help limit the insertion of the connector through the hole H by abutting the outer surface of the wall of the box adjacent the edge of the hole, see Figure 4. The, lower surface of the bent tang 28 preferably is spaced above the root line l3 a distance equal to the dimension '1 wherewith to square the connector in. relation to the wall K when the former has engaged the latter.
As best shown in Figure 7 the blank is slit along the line 21 to define the lower edge of'thewing 6 and permit its free folding along the line independently of the extreme leftward finger 5A and the narrow strip 29f of stock through which the finger 5A is: attached, tethe panel 2A. Itis Therefore; the
praetlcable eliminate the: fi ger 5A- and; the; strip: 29;- entirely in thamanufacture ofmy" Q0119" hector but I prefer; toretain-these-parts; or. a,- portion? thereof as suggested by. the dotted-line 30; wherewlth ta'establish. a normalf idlemonditlonf of the; connector; with; the: wings spaced:
apart and the=fing-er 5A with-thestripw29bridging; the gap between the wings-much as showninliiggure. 1., With this arrangement av manual oft.-
setting; of the wings and corresponding distortionof lthe leevefl permits the finger 5A and the strip 29;-to-begforcedradially inward and in underlap ping: relation to the root of; the wing. l and: the finger adjacent thereto-and permits the wings to be brought; close together with consequent sub-- normal reduction in the diameter- Qf. thewhole: sleeve to; permit: the; lower endofthe: sleeve-with the out-turned ears I4 to be freely inserteddntox the: hole; H in the; first. instance. Thereupon spreading-the wings fi and 1: andewithdrawing the finger; 5A; and strip- 2 9 out to circumferential alignment with the otherfingers; and the. lower pontion of the'sleeve 2 will bring the sleeve to; itsnorma-l position withinthe holeHbutshort of gripping engagement therewith. Such, a condition; is suggested in, Figure 1- and; as-presently-= advised is preferable preliminary to the insertion:
of; the-conduit-G and preliminary to the forcible expansion ofthe sleeve to-beginthe gripping of theperiphery of the hole and conduit as hereinabove described. ThiSJDEOViSiOII; of what I; term a; normal state for the connector With-theiW-ings spaced apart also insures, that: the lower edges of:
he wings W-ilIJbear at more Widely spaced. points:
on the; surface, of the; wall Kv of the outlettbox whilstthe lower face of. the. tang; 28 bears; onthe walloppositely thereofwherebya to: give: a three point contact through which the connector" is squared. with respect to the: wall- K and more effectively restrainedfromv wobbling; or. tipping with respect thereto. Furthermore in the;-n ormali idle state of: the connector with thewings: spaced and approximately parallel, and: assuming:
the: lower end of thevconnector'to be loosely and! properly 'locatedin:the-hole, thelzstrapsllli andldican be given their maximum expansionfor reception of a large conduit by manually squeezing: the: top of the wings, see-Fig; 6; without. necessarily contracting the bottom of the sleeve 21ordisturbing; the relation of the connector with, the: hole;
This latter operation Will be facilitated. especially" if the screw 8 haveits end about midway be tween the wings tomaintain the spread of the lower ends Whilst theupper: ends: are contracted.
The blank of Figure 7- canbe readily benli rolled" and formed to the shape and structure of the connector of- Figures l6- and being of onepiece requires no-assembly of-separablepart's except the insertion of thescrew 8; Inuse; the
screw 8 is backed oli and if theresiliencyof the connector does not tend to' full sleeve contra'etion, the wings it andl. may bemanually pressed together or to proximity for full or desirable;
contraction of the sleeve and expansion of the straps. With the, connector contracted" to its normalor sub-normal, state it maybe pushed" passed beyond thelower orinner edge-. of the periphery of the hole H. The conduit C may then be conveniently inserted into the connector and into the converging passage I8 until the end of its sheath abuts and seats on the concave surfaces-l9 at a point above and adjacent the throat I1, the fingers yielding somewhat under the thrust of the conduit; The screw 8 is then turned inwardly to separate the wings and expand the sleeve within the hole H and contract the clamping straps 3 and 4 upon the conduit. As the sleeve expands theflngers 5 by reason of their initial yielding maintain or tend to maintain snug yielding contact with the end of the 'conduitsheath and together with the clamping straps 3 and 4 continue to hold the conduit firmly to the connector and in coaxial alignment therewith normal to the plane of the wall K of the-box. 7 7
Upon "final expansion of the sleeve the connector is positively located and secured in the wall of the box by the tang '28 and the lower edges of the wings 6 and 1 bearing on the outside of the wall and by the ears l4 bearing oppositely on the inside of the wall. The ears l4 once the sleeve is expanded project into the box and project beyond the periphery of the hole H as shown. and hold the connector against withdrawal outwardly. The tang Z8 and the wing 6 and I abut the outer surface of the box on opposite sides of the hole'I-I and opposite of the ears l4 and prevent the connector from moving into the box or moving relative to the wall. If the dimension T is somewhat less than the thickness of wall K the sloping outer sides of the ears [4 will engage the inner peripheral edge of the hole H and draw the connector into snug fit against the wall of the box, thewall being gripped between the tang and wings and the inclined ears.
'While I have described a preferred form of my invention, changes, improvements and modifications will occur to those skilled in the art without departing from the spirit and substance of my invention or the teachings hereof, and I do not care to be limited in the scope of my patent in any manner other than by the claims appended hereto.
l. A conduit connector adapted to receive and grip a conduit and be received within and expanded into gripping engagement with the peripheraledge of a hole in the wall of a connector receiving instrumentality comprising an integral sleeveincorporating two similarly formed relatively movable parts symmetrically disposed with respect tothe longitudinal axis of the connector, each part having portions spaced apart longitudinally and disposed on opposite sides of said axis and lying diametrically opposite corresponding juxtaposed portions in the other part, one diametrically opposed pair of said portions lying near one end of said connector. and being expansible and engageable externally with said edge when said parts are diametrically displaced, the other pair of said portions being contractable and engageable internally with said conduit when said parts are diametrically displaced, and means for displacing said parts relative to each other.
2. The connector of claim 1 in which one pair of said portions are formed from the stock of said sleeve and in part severed therefrom and crossed therewithin.
3. The connector of claim 1 in which said other 7 pair of said portions comprise substantially semicircular crossing straps with their ends respectively connected to said parts on sides of said axis oppositely of the disposition of the middles of said portions.
4. The connector of claim 1 in which said pairs of portions each extend for substantially a full circle at approximately opposite ends of said connector.
5. The connector of claim 1 in which said parts are interconnected and relatively movable, each portion of a said pair when constrained against movement serving as a fulcrum about which said means moves a part and the other portion thereof.
6. A connector for connecting a conduit to an outlet box comprising a split sleeveadapted to be inserted within a hole in the wall of said outlet box, means for expandingsaid sleeve within said hole to secure said connector to saidbox, arcuately looped mutually crossed straps adapted to clasp said conduit between them, one end of each strap being secured respectively at adjacent points to the wall of said sleeve, said ends being relatively immovable upon expansion of said sleeve, the other ends of said straps being connected respectively adjacent the longitudinal edges of said split sleeve and adapted to move away from each other upon expansion of said sleeve to cause said straps to clamp said conduit between them.
7. The connector of claim 6 in which said sleeve has a plurality of fingers bent inwardly from and into one end thereof to lie therein, and define a tapered passage converging. from the end toward the interior of said sleeve, said fingers being adapted to resiliently contact the sheath of said conduit and limit its insertion into said connector. 7
8. The connector of claim 6 in which said sleeve has a plurality of fingers bent inwardly from one end thereof to lie therein, and define an hourglass shaped passage converging'to' a throat of minimum diameter spaced from the end of said sleeve, said fingers inwardly of said throat defining a seat adapted to resiliently contact the end of the sheath of said conduit and limit its insertion in said connector and align the same coaxially thereof.
9. A connector adapted to be inserted within a hole in the wall of an outlet box for connecting a conduit thereto comprising means for expand projecting beyond the periphery of said'hole' when said connector is expanded and preventing withdrawal of said connector from said hole.
10. A connector adapted to be inserted through a hole in the wall of an outlet box and removably secure a conduit thereto comprising a split sleeve, said sleeve having two substantially radial outstanding wings, a screw threadedly extending through one of said Wings and adapted to thrust against the other of said wings and secure it within said hole and expand said sleeve forcibly circumferentially, the lower edges of said wings abutting said wall and limiting the insertion of e the connector therethrough, a pair of crossed looped straps connected respectively to said wings embracing said conduit and upon expansion of said sleeve being adapted to constrict and clamp said conduit therebetween, a plurality of stifily resilient fingers bent upwardly from th bottom 01 said sleeve interiorly thereof, said fingers being tapered from both ends to a central narrow portion and adapted to be bent at said narrow portion at an obtuse angle to define a substantially conical converging passage, a throat, and a substantially conical diverging passage, the mouth of said diverging passage comprising ears adjacent the roots of said fingers projecting radially beyond said sleeve and into said box and adapted upon expansion of said sleeve to project beyond the periphery of said hole and prevent withdrawal of said connector therefrom, and a tang struck from said sleeve substantially diametrically opposite said wings and adjacent to and spaced from the roots of said fingers and engageable with said wall in opposition to said ears.
HENRY D. STECHER.
REFERENCES CITED The following references are of record in the Number Name Date 442,837 Ward Dec. 16, 1890 1,215,595 Weikert et a1 Aug. 11, 1914 1,243,748 McMurtrie Oct. 23, 1917 1,315,484 Fesler Sept. 9, 1919 1,364,529 Thomas Jan."4, 1921 2,430,809 Flora et al Nov. 11, 1947