US2219326A - Electrical appliance plug connector - Google Patents

Description

@ci 29, 194 0, G. JfM EQER 2,219,325

ELECTRICAL APELIANCE PLUG CONNECTOR Filed Nov. 14, 1958 2 Shets -Sheet 1 Get, 29, 1940. G. .1. MEUER ELECTRICAL APPLIANCE PLUG CONNECTOR Filed Nov. 14, 1938 2 Sheets-Sheet 2 mated Oct. 29, 1940 UNITED STATES ELECTRICAL APPLIANCE PLUG CONNECTOR George J. Meuer, Milwaukee, Wis, assignor to Cutler-Hammer, Inc.,- Milwaukee, Wis., a corporation of Delaware Application November 14, 1938, Serial No. 240,274

8 Claims. (01. 173-332) This invention relatesto improvements in electrical appliance plug connectors. The invention more particularly relates to. improvements in electrical appliance plug connectors of the socalled clamp type disclosed and claimed in my Patent No. 1,898,589, dated February 21, 1933.

A primary object of the invention is to generally improve the details of construction and assembly of the parts and the operative characteristics of electrical appliance plug connectors of the aforementioned character. I

Another object is to provide improved means for insuring maintenance of the parts of said device in properly assembled relation under all conditions when in use. i

Another object is to provide novel means for insuring against relative lateral displacement of the casing sections, while permitting the desired degree of forcible separation of portions of the adjacent faces thereof as an incident to plugging attachment of the device to a plurality of plug jacks.

Another object is to provide a novel form of resilient or flexible cord guard and novel means for externally attaching the same to the casing sections.

Another object is to provide an arrangement whereby the cord guard may be utilized. to restrain the external assembling and biasing clips against accidental separation from the assembled parts of the casing. 7

Another object is to provide a device of the aforementioned character enabling use of a dowel or guide pin of simple and inexpensive form.

Another object is to provide such a device with a novel form of strain relief for the terminal ends of the wires of a conductor cord.

Another object is to provide adevice of the aforementioned character having an unusually neat and attractive appearance.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be of without departing from the scope of the appended claims.

In the drawings,

Figure l. is a front elevation (slightly larger I than normal size) of a clamp type electrical ap-.

pliance plug connector constructed in accordance with my invention.

Fig. 2 is a side elevation of the device shown in Fig. 1. A

Fig. 3 is an interior view of one of the two sec-' tions of the molded insulating casing.

Fig. 4 is a view (double scale, and partly in section) on the line 44 of Fig. 2, the various parts of the device being shown in assembled relation.

Fig. 5 is a vertical view on the broken line 55 of Fig. 1, certain parts of the device being shown in elevation.

Fig. v6 is a perspective view of one of the two substantially U-shaped' resilient wire clips employed in the device of Figs. 1 to 5.

Fig. 7 is a perspective view of the punched insulating plate which provides a strain relief for the terminal ends of the wires, as shown in Figs. 4 and 5.

, Fig. 8 is an elevation of a slightly modified plug connector as constructed in accordance with my invention.

Fig. 9 is a fragmentary interior view, partly in elevation and partly in section, of the device shown' in Fig. 8.

Fig. 10 is a perspective view of the alternative form of punched insulating strain relief plate shown in Fig. 9, which may be substituted for u cross section, being shown in elevation in separated relation.

Referring first to that form of the invention shown in Figs. 1 to '7 and 12, the numerals l5 and I6 designate the pair of molded sections which jointly form the insulating casing of the connector. In practice the sections I5 and 16 are identical with each other in respect of the exterior contour and surfaces thereof, and in respect of the interior recesses thereof, with the exception that section I5 is provided with a recess l5 (Figs. 4 and 12) of hexagonal form in transverse cross section to. accommodate with a drive fit either end of the-cylindrical dowel pin I1 (Fig. 12 whereas the section Hiis provided with a recess l6 (Fig. 3) of circular form in transverse cross section, and of relatively larger d a eter than pin 11 to freely receive the free into the recess of hexagonal form in transverse end of the latter and to permit the required degree of tilting or separating movement of sections l and I6, while preventing substantial lateral or longitudinal movement of said sections relatively 5 to each other.-

It follows that sections l5 and I6 may be produced (at different times) from the same set of molding dies, it being only necessary to provide a die stud or insert to produce the hexagonal recess l5 when molding section l5, and to substitute for such die stud another stud adapted to produce the circular recess li when molding section Hi.

Although sections l5 and i6 might be made identical in all respects (in accordance with the teachings of my aforementioned Patent No. 1,898,589), such an arrangement requires machining of a rod or bar of hexagonal or other polygonal form in transverse cross section to tion (as shown in Fig. l of said Patent No. 1,898,589). With the arrangement herein discl0sed, however, the dowel pin I! (Fig. 12) is simply formed by cutting the same to the desired length from a commercially available rod or ba1',of circular form in transverse cross section. Other forms of doweling arrangements may, of course, be-employed. Thus, if desired, the sections I5 and I6 may be provided with dowel-pin recesses'of identical form and dimensions, the dowel (not shown) comprising a flat punching having a relatively large 'end adapted for a drive or press fit into one of the like dowel recesses and a relatively small or reduced end adapted for a relatively loose fit within the other dowel recess. V The flat puncheddowel in such case may, of course, be composed either of sheet metal or an insulating" material of -the required strengthand rigidity.

Casing sections l5 and I i (Figs. 3 to 5) are provided in the adjacent faces thereof with like complementary recesses to accommodate a pair of combined contact and terminal units I8 of identical form. Each unit l8 preferably comprises a punched and stampedsheet metal member which is bent upon itself, or reflexed, to provide at the forward end thereof a pair of contact arms arranged in socket-forming relation, the forward ends of said contact arms being flared as shown to facilitate insertion of a plug jack of suitable form (not shown) therebetween. The shank of a binding screw l9 takes into tapped openings ,(not shown) provided in the upper and lower layers of said terminal portion, the opening inthe lower layer including an extruded rim I la (Fig. 5) whereby a thread of suillcient length is provided. The upper layer of each terminal portion isfprovided at its edges with substantially integral parallel lugs l8 to provide a guard for a wire loop to be clamped in place by the head of screw l9.

Units 18 and the complementary recesses in sections [5?" are cooperatively formed to insure against substantial longitudinal or lateral displacement of the former in either direction with respect to said casing sections. Sections l5, l6 are provided at the lower ends thereof with grooves having intermediate portions I5 l5 and I6, l6, respectively, with flat portions l5, I5 and li l6 at the respective opposite sides of said intermediate portions. The intermediate portions of the grooves, such as I5 I 6 (Fig. 5)

are. adapted to accommodate and guide plug jacks of substantial thickness or diameter, such as those of round or elliptical form in cross secprovide a portion of reduced circular cross section; whereas said intermediate portions jointly with the flat portions, such as I5 l6 (Fig. 5) are adapted to .accommodate thin and wide, or

' blade type plug jacks.

Sections l5 and I6 are respectively provided exteriorly thereof with grooves l5, l5 and Ii, Hi extending downwardly from the upper ends thereof on opposite sides of the longitudinal center line of each casing section throughout the major portion of the length thereof. Said grooves are preferably of rectangular channelshape in transverse cross section, and the grooves in each section are slightly curved inwardly to.- ward each other throughout their length, as best illustrated in Fig. 1. The arrangement is such that grooves li and l5 (Fig. 5) are alined with each other, and grooves I6 and I5 are alined with each other. Forcibly insertable downwardly into the alined pairs of grooves IS, IS and Ii, l5 are a pair of flat, substantially U-shape resilient wire members 20, the wire of which said members are formed being preferably of substantially rectangular form in cross section. Members 20 when formed as shown in Fig. 6 are preferably provided with a plating of nickel.

As shown in Figs. 1 and 5, members 20 fit rather snugly within the alined. grooves of the respective pairs, and in a relation substantially flush with the respective outer surfaces of the casim sections 15 and I6 (see Fig. 5). The curvature of said grooves (Fig. 1) causes a corresponding curvature or bending of the arms of members 20, to assist in restraining the latter against accidental displacement of said members from the assembled casing sections. Said curvature of the arms of members 20 also provides for application of the maximum degree of spring pressure upon the casing sections at spaced points adjacent to the longitudinal center line of the casing as a whole, and closely adjacent to the point of initial spreading of the pairs of contact arms,

incidental to insertion therebetween of plug jacks. Also as shown in Fig. 6, the arms of each member 23 are initially bent or angled inwardly toward each other to insure a predetermined degree of external spring pressure upon the casing sections.

The connecting portions 20" of members 20 are adapted to seat or rest against the upper end surfaces of easing sections l5, l6. Said casing sections are provided at the upper ends thereof with integral extensions which jointly provide a head portion 2| (Fig. 5) of substantially frustoconical contour, with an annular groove or neck portion 22 therebelow, and an annular portion 23 (Figs, 1, 2 and 5) below said neck portion-and having a diameter substantially corresponding to the maximum diameter of head portion 2|. To provide clearance for wire clip members 2| and to facilitate insertion and removal of the latter, head portion 2| and annular portion 23 are provided with flats or cut-away portions 2|- (Fig. 5) and 23 (Fig. 4) respectively.

The aforementioned extensions are provided with complementary grooves 2i and 25, which jointly provide a passage for the conductor cord I 26 (Figs. 4 and 5), the outer end portions 24 and neck portion 22, the lower end of said cord guard also overlying the connecting portions of members 20 to further assist in retaining the latter in assembled position.

, In the device of Figs. 1- to 5 said cord guard is formed of a single length of resilient wire, coiled in the manner best illustrated at 21 in Fig. 1 to provide a closely wound, enlarged lower end portion 21 of substantially frusto-conlcal contour I to accommodate said head portion 2|, the lower of the guard.

end coil 21 of said guard being wound to a substantially reduced diameter,-whereby the same is adapted to snap into positive but releasable engagement with the shoulder formed between-neck portion 22 and head portion 2|. Also as best illustrated in Figs. 1 and 4, said lower end coil 21 is adapted to overlie the connecting portions 20 of members 20 to assist latter against accidental upward displacement relatively to casing sections l5 and i6. As will be apparent from Figs. 1, 4 and'5 the lower end portions 21 21 of the cord guard 27 cooperate with the casing sections to assist in restraining the latter against substantial lateral or longitudinal displacement relatively to each other. Moreover, said lower end portions of the guard do not substantially interfere with the required degree of separating movementof the lower ends of the casing sections as an incident to cooperative engagement 'of the socket contacts with plug jacks. The upper end portion 21 of cord guard 21 has the coils thereof spaced to a predetermined degree to. afford the desired degree of flexibility thereof. Cord guard 27 is provided at its upper endwith an annular sheet metal member or ferrule having a portion 28 telescoping into said cord guard, and a downwardly extending exterior flange 2B (Figs. 1 and 2) the lower edge of which is spun inwardly, as shown at 28? in Fig. 1 to retain said member in position, and toprovide an enclosure for the 'cut end of the upper end coil Casing sections l5 and 16 are respectively provided with integral upwardly and outwardly angled projections 29 and 30 of trapezoidal form," as shown in Fig. 1; portions of the exposed surfaces of said projections being grooved, as shown at 30* in Fig. 1, or otherwise roughened to afl'ord I a proper finger grip (see Fig. 2) to facilitate attachment of the connector to or removal thereof from a electrical appliance. Casing sections IS and it are likewise provided at opposite side edges therof with complementary or matching upwardly and outwardly and then inwardly curved projections to jointly provide finger" grip portions 3| and 32. The electrical appliance plug connector so constructed is very neat in appearance, and the same may be embellished by a suitable design to increase the attractiveness thereof, as shown.

The ornamentation or design illustrated herein is displosedand claimed in Design Patent No.'

109,735, granted May 1'7, 1938, to Q. B. Stevens.

As indicated in Fig. 5, after a slight degree of spreading of the contact'arms of units 18 (upon engagement thereof with plug lacks) the arms will engage the respective blocks'lS, l6 to cause said clips spreading of the latter against the spring bias afforded by'the arms of the wire clips 20. The clips 20 are relatively longer and substantially heavieFthan the clips 22 disclosed in my prior Patent .No; 1,898,589, aforementioned; whereas the contact arms against. the plug jacks under all conditions. The clips 20 and all other parts of the present device are extremely rugged and durable and are not likely to get out of order. The

combined contact and terminalmembers it are wires, as an incident to in restraining the I 26 is cut to the desired rangement being 2|] insure a proper degree of pressure of formed of a suitable metal, such as brass or steel, preferably silver plated. Members l8, if formed of :steel, may alternatively be provided with a plate or covering of zinc. In practice the binding screws I! are formed of brass or steel, to correspond with the particular metal employed in forming the members Hi. The screws l9, if formed of steel, may be silver plated or zinc plated; and if formed of brass the same are preferably silver plated.

In practice I prefer to provide simple means to insure against any substantial degree of strain upon the terminal ends 26, 26 of the individual a pull upon the conductor cord 26, whereby to prevent accidental loosening of the binding screws l9. Accordingly the casing sections l5 and it are internally recessed at I5 (Fig.4) and Iii (Fig. 3), at the inner ends of the respective cord grooves 24 and 25, to accommodate the diametrically opposed portions of the substantially circular intermediate enlargement 33*.of a flat, punched plate 33 of insulating material (see Fig. '7). Enlargement 33 is provided with a centrally located circular opening 33 to provide for downward insertion of conductor 26,

including the individually insulated wires 26, 26 (Fig. 4), the outer insulating covering of the cord being cut away in a plane substantially flush with 33, laterally across the upper surface of plate 33, and downwardly through groove 33. Wire length, and a portion of the free end thereof is bared'and bent to hook or loop form, to provide for proper clamping engagement of the head of a screw i9 therewith. In like manner the insulated wire 26 is bent laterally over the lower surface'of plate 33, then upwardly -through groove. 33, across the upper surface of plate 33, and then downwardly through groove 33 wire 26 being cut to thedesired length, and a portion of the freeendthereof is hated and bent to loop form for clamping engagement thereof by the head of the other screw l9.

Sections l5 and I6 are recessed as shown to ac commodate the arms 33, 33 of plate 33, the arsuch that the-individual wires 26*, 26 are snubbed at a multiplicity of points against plate 33, whereas a portion of each of said wires is additionally clamped between the upper surface of plate 33 and the upper end walls of the-recesses formed in sections l5 and I6. As will be apparent fromFig. 4, any strain incident to an outward pull upon the cord 26 is absorbed by the plate 33 and the intermediate portions of the wires, 26, 26 associated therewith, without reaching the bored end portions of the wires which are clamped by the heads of screws l9. I have shown, and will hereinafter describe, other forms of strain relief devices which, it is to be understood, may be substituted for that illustrated in Figs. 4, 5 and '7.

The form of electrical appliance plug connector illustrated in Flgs. 8 and 9 is substantially'like that aforedescribed but dlflers therefrom in respect of certain structural details. Thus the in-v sulating casing may comprise a pair of sections 34,

if a doweling arrangement like that disclosed in my prior Patent .No. 1,898,589 is employed; or said sections 34 and 33 may diifer from each other only in respect of the relative shapes of the dowel recesses (such as l5 in Fig. 4 and I3 in Fig. 8), if a cylindrical dowel pin like that shown in Fig. 12 is employed. Sections 34 and 33 may be provi'ded with complementary internal recesses ex ,actly like those of sections l3 and l3 aforedescribed.

I'he substantially U-shaped resilient wire clips 33 of Figs. 8 and 9 are substantially like clips 23 aforedescribed, but are preferably slightly shorter than the latter. The relative shortness of clips 33 is necessitated by the fact that sections 34 and 35 are provided at the upper ends thereof .with grooves 34', 34 (Fig. 9) and 35", 33 (Fig. 8) which accommodate, in a substantially flush relationship to the upper end surfaces of sections 34 and 35, the connecting portions 33'- of membars 33. In order to facilitate removal of clips 33, as by inserting the blade of ascrew driver or the like under the connecting portions 33 thereof, the outer walls of groove 34?, 34 and 33!, 33'' are angled outwardly, as shown at 34, 34 (Fig. 9).and 35,'35 (Fig.8).

Casing sections-34 and 35 are respectively provided at the upper ends thereof with integral extensions, the upper ends 34 and 33 of which jointly provide a head portion of substantially frusto-conical contour; and the lower ends 34f and of which extensions are of reduced size, 4

to provide an annular groove between said' head portion and the upper end surfaces of sections 34 and 35.' Said casing. sections and their extensions are internally grooved, as shown. in Fig, 9, which grooves Jointly provide a passage for the conductor cord 23.

The cord. guard in this instance preferably. 40 consists of a molded resilient rubber member 31 having'the extemal' contour illustrated in full lines in Fig. 8, said member being internally r'e-.

cessed as shown at 31* to accommodate said frustoconical head portion, and thesame being provided with an annular inwardly extending flange '31" which fits rather. closely between said head portion and the upper end surfaces of casing sections 34 and 35. The lower end of member 31 is of sufficiently large size to overlie the grooves in the upper endsurfaces of sections 34' and 33 and the connecting portions 33 of clips 33 to assist in restraining the latter against accidental upward.

, displacement. The upper end portion 31 of member 31 is of gradually reduced size to increase the flexibility thereof, the same being provided with a centrally located passage 31 to accommodate with a snug fit the conductor cord 23 (see Fig.9). Member 31 is provided at its upper end with an external annular bead 31 (Fig. 8) to strengthen the same and to provide a more finished appearance to the connector as a whole. The strain relief device shown ui Figs. 9 and 10 is in general quite similar to that aforedescribed,

' the same comprising a flat punched insulating 35 plate 33 having an intermediate enlarged portion 33 of substantially circular contour, with a centrally located circular opening 33 formed there:

in. Member 33 is provided with diametrically opposed arms 33 and 33, am 33 having a relatively small circular opening 33' formed intermediate the length thereof, and a notch or groove 33 in the outer end thereof. Similarly, arm 33 is provided with an opening 33' andan end groove or notch 33. 1

" When wiring the connector (see Fig. 9) a" m I 2,919,826 if tion of the outer insulating covering of cord 23 is removed, and said'cond is inserted through opening 33 to the extent indicated. Wire 23 is bent laterally over the lower surface of plate 33, with .ing thereof by the head of the terminal screw- II. In like manner wire 23'' is bent laterally over the lower surface of plate 33,- the bored end portion thereof being threaded upwardly through opening 33', then bent laterally over the upper surface of plate 33, and-then bent to extend downwardly through groove 33'', the free end of the wire being looped for clamping thereof by the head of the other terminal screw IS. The

connections between the wire ends and'the terf A further modified form of strain relief device adaptable for use in coniunction with either form of connector is illustrated in Fig. 11, the same comprising a flat punched insulating plate 33 opening 33'' and bent laterally to underlie the.

respective arms 33 and 33 A single length of non-combustible thread of insulating material looking, or end snubbing, relationship around the cord 23 above plate 33, in the manner indicated at'43. Thereafter the. thread is carried across a portion of the upper surface of plate 33 and wound a number of "times around arm 39 and J the insulated portion of wire 23" which underlies the same, as shown at 43". After a few turns of the thread the same is crossed diagonally, as

J shown at 43'', then wound in the reverse direction a larger number of times around arm 33 and the insulated portion of wire 23' which underlies the same, in the manner illustrated at 43. 'The thread is then again crossed diagonally, as shown at 43'', and the winding 4|I' about arm- 33 and wire 23 completed, whereupon the remaining portion of the" thread is extended across the upper surface of plate 33 and again wound a number of times around the cord '23, as aforeindicated at 43.. Y

may be wound in a manner to provide forknotting or tying thereof after completion .of the winding operation. f- 3 'Ihe terminal end of the asbestos'thread does (such as asbestos) is then wound, first, in self- If desired, of course the thread having an enlarged intermediate portionv 39 of substantial circular contour, said intermediate 2o 1 strain relieving function of the device upon the gage and interlock with the fibers of the previousiy wound portions thereof. Moreover, after positionlng of conductor 26 and its attached plate 39 in properposition in the recesses of the casin sections, the walls of the cord passage formed in the latter will further assist in preventing unwinding of the asbestos thread. As shown in Fig. 11, only relatively small lengths of the wires 28 and 26' are bared and looped for cooperation withthe shanks and heads of the respective binding or terminal screws. The functioning of the device of Fig. 11 when assembled with respect to the insulating sections of the casing and other parts of the connector will be at once apparent. The upper surface of plate 39 will abut, or tend to abut, against the upper end walls-of the recesses in the casing sections. In the event of a pull upon cord 26 the insulated portions of 26, 26' are not only snubbed against the lower surface of plate 39, at the points where said wires extend upwardly through. opening 39 but due, to the relatively tight winding of the thread at All and 'iMthere is a very great resistance to any upward movement or slippage of the wires relatively to plate. 39.

What I claim as new and desire to secure by Letters Patent is:

1. An electrical appliance plug connector com prising an internally recessed longitudinally divided molded insulating casing, the opposed sections of said casing jointly having atleast one pair of alined-grooves formed thereinand extending downwardly from the upper end of said casing upon the outer surface of the latter, a substantially U-shaped resilient metal clip forcibly insertable downwardly into said a pair of' grooves to straddle the respective casing sections to assist in retaining thelatter in assembled relationship to each other, said casing sections having at the upper end thereof integralextensions with complementary internal grooves to jointly pro'- vide a cord passage, said extensions being formed externally to provide a head portion with an annular groove or neck portion therebelow, and a hollow,- resilient cord guardmember the lower end of which is forcibly movable downwardly over said head portion and positively but releaslatter is prevented.

ably engaged with the shoulder formedbetween the latter and said neck portion, whereby accidental upward displacement of said cord guard is prevented, said lower end of said cord guard also overlying the upper end portion of said metal clip whereby accidental upward displacement of the 2. An electrical appliance plug connector comprising an internally recessed longitudinally. divided molded insulating casing, the opposed sections of said casing jointly having alined pairs of grooves formed therein and extending downwardly from the upper end of saidcasing upon the outer surface of the latter,a pair of substantially U-shaped resilient metal clips forcibly insertable downwardly in to the respective pairs of grooves to straddle therespective casing sections to assist in retaining the latter in assembledre lationship to each other, said casing sections haying at the upper end thereof integral extensions with internal grooves to jointly provide. a cord guide, said extensions being formed externally \to provide a head portion with an annular grooveor neck portion ther'ebelow, and a hollow, resilient 3 cord guard member the lower end of which is forcibly movable downwardly over said head portion and positively but releasably engaged with the shoulder formed between the latter and said neck portion, whereby accidental upward displacement of ad cord guard is prevented, said lower end of said cord guard also overlying the upper end portions of said metalclipsi-whereby accidental upward displacement of the latter is prevented.

3. An electrical appliance plug connector comprising an internally recessed longitudinally di- -vided molded insulating casing, the opposed sections of said casing jointly having two alined pairs of groovesformed therein and extending downwardly from the upper end of said casing upon the outer surface of the latter, said pairs of alined grooves being arranged in equally spaced 'relation to. the longitudinal center line of said casingvand extending throughout the major portion of the length of the latter, said pairs of alined grooves being curved inwardly toward each other throughout the length thereof, a pair of substantially U-shaped flat, resilient metal clips the arms of each of which are forcibly insertable jointly into one of said pairs of alined grooves to straddle the respective casing sections to assist in retaining the latter in assembled relationship to each other, the curvature of said grooves acting to efle'ct corresponding curvature of the arms of said clips as an incident to insertion of the latter, to assist in restraining said clips against accidental displacement from said grooves, said casing sections having at the, upper end thereof integral extensions with complementary internal grooves to Jointly provide a cord passage, said extensions being formed externally to provide a substantially frusto-conical head portion with an annular groove therebelow, and

an elongated, hollow,.resilient cord guard -mem-' her the lower end of which is formed to require forcible movement thereof downwardly over said head portion and to provide for positive but releasable engagement with the shoulder formed between said head: portion and said annular groove, to thereby assist inretaining said casing sections in assembled relation and to prevent accidental upward displacement of said cord guard, said lower end of said cord guard also-overlying the upper ends of said metal clips to further assist in retaining the latter in assembled relation .to said casing. f

4. An electrical appliance plug connector comprising a longitudinally divided molded insulating casing, said casing having. a plurality of pairs of complementary recesses respectively arranged provide a pair of ,shaped resilient wire forcibly insertable into on opposite sides of the line of division thereof,

a plurality of combined contact and wiring terminalunits loosely positioned within the respective pairs of complementaryrecesses, each unit comprising a single metal member reflexed to forming relation, the opposed sections of said casing jointly having alined pairs of grooves formed therein and extending downwardly from the upper end of said casing upon the outer surface of the latter, said pairs of alined grooves being arranged in equally spaced relation to the longitudinal center line of said casing and extending throughout the major portion of the length of the latter,

clips the arms of which are the respective pairs of alined grooves in said casing sections to assist in retaining the latter in assembled relation, said casing sections having at the upper ends therecontact arms arranged in socket a, pair of substantially U- which isformed to accommodate said head por-* tion and the lower end coil of which guard is formed to snap into said annular groove,' and said lower end coil overlying the upper ends of saidclips to restrain the latter against upward displacement.

5. An electrical appliance plug connector comprising a longitudinally divided molded insulating casing, the opposed sections of said casing jointly having alined pairs of grooves formed therein and extending downwardly from the upper end of said casing upon the outer surface ofthe latter, said pairs of alined grooves being arranged in equally spaced relation to the longitudinal center line of said casing and extending throughout the major portion of the length of the latter, said pairs of alined grooves being curved inwardly toward each other throughout in assembled relationship to each other, the

curvature of said grooves acting to eifect corresponding curvature of'the arms of said clips as' an incident to insertion of the latter, to assist in restraining said clips against accidental dis-- placement from said grooves, said casing sections having at the upper ends thereof integral extensions with internal grooves to jointly provide a cord passage, said extensions being formed externally to provide a substantially frusto-conical head portion with an'annular groove therebelow,

a coiled wire cord guard member the lower portion of which is enlarged toaccommodate said head portion and the lower end coil of which guard is adapted to snap into said annular groove, whereby accidental upward displacement of said'guard is prevented, and said lower end coil also overlying the upper ends of said wire clips to restrain the latter against upward displacement;

6. An electrical appliance plug connector comprising a longitudinally divided molded insulating casing, said casing having a plurality of pairs of complementary recesses respectivel arranged on opposite sidesgof the line of divisionL-thereof, the opposed sections of said casing jointly having, alined pairs of grooves extending from the meetingsurfaces of the casing sections and then downwardlyfrom the upper ends of said sections upon the respective outer surfaces of the latter, said pairsof alined grooves'being arranged in equally spaced relation to the longitudinal center line of said casing. sections and extending throughout the major portion of the length of the latter, a pair of substantially U-shaped resilient wire clips the arms of which are forcibly insertable into :the respective pairs of alined grooves insaid casing sections, the connecting portions of said clips being adapted to seat within said grooves in a substantially flush relation to the upper end surfaces of said casing sections, said casing sections having at the upper ends thereof integral extensions with internal grooves to jointly provide a cord passage, said extensions being formed externally to provide a head portion with an annular groove therebelow, and a hollow, resilient cord guard member the lower end of which is forcibly movable downwardly over said head portion and positively but releasably engageable with the shoulder formed between the latter and said annular groove, said lower end of said cord guard overlying and engaging the connecting portions of said clips whereby accidental upward displacement of the latter is prevented.

7. An electrical appliance plug connector comprising an internally recessed iongitudi-' nally divided molded insulating casing, a substantially U-shaped resilient metal clip straddling the respective casing sections to assist in retaining the latter in assembled relationship to each other, said casing sections having at the upper end thereof integral extensions, said extensions beirm formed externally to Jointly pro-' vide ahead portion, and a hollow resilient cord guard member the lower end of which is forcibly movable downwardly over and into interlocking engagement. with said head portion, whereby accidental upward displacement, of said cord guard is prevented, said lower end of said cord guard also overlying the upper end portion of i said metal clip whereby-accidental upward displacement of the latter is prevented.

8. An electrical appliance plug connector com- 1 prising an internally recessed longitudinally divided molded insulating casing, the opposed sections of said casing Jointly having two alined pairs of grooves formed therein and extendng downupper end thereof'integral extensions with complementary internal grooves to Jointly provide a cord passage, said extensions being formed externally to'provide a head portion wi an annular groove therebelow. and an elonga hollow, resilient cord guard member the lower end of which is formed to require forcible movement thereof downwardly over said head portion and to provide for positive but releasable engagement with the shoulder formed between said head portion and said annular groove, to thereby assistin retaining said casing sections in assembled relation and to prevent accidentalupward displacement of said cord guard, said lower end of said cord guard also overlying the upperends of said metalclipstoassistinretalningthelatterin' assembled relation to said casing. SiEORGE J. MEUER.

Images