US2769154A - Electrical connector - Google Patents

Description

Oct. 30, 1956 A. GREENBAUM 2,769,154

ELECTRICAL CONNECTOR Filed Aug. 215, 1949 3 Sheets-Sheet 1 F162 4 F IGJ 25 H II I '11,} :iim 2 INVENTOR; ARTHUR GREENBAUM BY n 4 5 m,

, 12 I7 d M a a ATTORNEY.

Oct. 30, 1956 A. GREENBAUM 2,769,154

ELECTRICAL CONNECTOR Filed Aug. 2:5, 1949 v s Sheets-Sheet 2 FIG? ' FIG. 8 23 22 A F: l

, INVENTOR k l L M v 32 ARTHUR snssuemu TI 15+ d -M ATTORNEY.

Oct. 30; 1956 A. GREENBAUM 2,769,154

ELECTRICAL CONNECTOR Filed Aug. 25. 1949 3 Sheets-Sheet 3 Z p l7 mfl'l I ['7' 5) Q a Ami C w FIG. I2

I4 cw INVENTOR. ARTHUR GREENBAUM BY java/4 gem ATTORNEY 2,769,154 Patented Oct. 30, 1956 ELECTRICAL CONNECTOR Arthur Greenbaum, New York, N. Y., asignor to Academy Electrical Products Corp., New York, N. Y., a corporation or New York Application August 23, 1949, Serial No. 111,958

19 Claims. (Cl. 339-99) This invention relates in general to a new fitting comprising an electrical connector of the insulation-piercing type adapted to establish a permanent current transmitting connection by impaled-pressure with an electrical conductor.

More particularly, the invention herein pertains to a} quick disconnect terminal presented in the form of an electrical cord-plug for use with stranded flexible wire conductors known as fiat wire, the use of which is increasing in connection with mobile lighting and other appliance circuits. Cord-plug terminals are adapted to disconnect with current-supply outlet receptacles and'energize all manner of electrical appliances which may be moved from place to'place in the'home, oflice and factory.

This is a continuation-in-part of my prior or parent cord-plug application, filed March 15, 1947, under Ser. No. 734,967-the particular embodiment of which is illustrated and the claims thereon being made herein. It follows, therefore, that the grant of the patent on the parent application is hereby waived in favor of this application covering the parent structure as well as the present improvements. The prior parent application Ser. No. 734,967 was abandoned after the instant application was filed.

This invention improves upon that principle known in the art as an insulation-piercing electrical connector wherein a pair of metallic barbs, spikes or points pierce the insulation and establish a permanent pressure electrical connection. This is accomplished by impaling the two flexibly stranded wires of a conventional fiat conductor for mobile type electrical appliances. Thus, screw fastened and soldered connections are avoided.

Concerning the state of the art of the piercing class of connector and its progress to date, one view to be taken thereof is that'the art assuch is somewhat confined to mere literature on the subject, as represented bynumerous prior patents, but without the connector coming into generaluse to supply all requirements of the trade. While the patent art contains a variety of teachings of the piercing connector principle for all three species thereof (terminals, splicers and taps), it appears that only the terminal class of such connectors has reached the market inrecent years--only the cord-plug species thereof-but without features making it sulficiently convenient and useful as to gain general acceptance in the trade.

Conventional cord plugs (electrical terminals) of the insulation-piercing type, in the patent art as well as those on the market, usuallyrequire the use of a tool (screwdriver or knife, etc.) in one way or another to prepare the wire (remove its'insulation and/or separate the two wires) and sometimes to'screw-fastcnthe wire on the plug. The present invention goes further by providing a cord plug which is entirely automatic, .and which may be quickly and conveniently installed on or attached by hand to a conductor without the use of any tools what- 2 soeverthere being no necessity for preparing the wire or usinga tool.

It seems especially true that insulation-piercing connectors thusfar proposed (especiallycord plugs and receptacles therefor) do not satisfy the trade now largely using the particular type of electrical wire, as herein treated. It may be described as a flat insulation-covered stranded flexible conductor of multi-wire form, the most generally used being a parallel longitudinallyjoined two-wire type for electric light and appliance circuits in general. Such flexible parallel wire conductors are covered by rubber or plastic insulation, are

wider'than=they are thick, and hence are referred to as flat wire. It is thatwire to which'this electrical connector is adapted.

A purpose of this invention is to provide a connector -which may be installed on flatinsulation-covered electric wire without de-insulating (no skinning, peeling, or

stripping) the protective covering therefrom-and also without need of separating the several (usually two) longitudinally-joined wires, that is, without dividing and pulling them apart-thus attaching the connector in a matter of seconds, automatically, and without need of a tool.

A further purpose is to provide an insulation-piercing type of connector embodying a new operating means of simple automatic form, which is manipulated by hand or finger pressure (requiring a minimum of manual effort) to attach it to a conductor and establish a pressure electrical connection of low resistance with the tightly compacted wire strands and alsosimultaneously establish a compression strain-relief grip of high pull-out value on the insulation.

The drawings The accompanying drawings with description and claims explain the inventionas preferred and embodied at this time for an understanding of the problems sought to be solved. Since the teachings herein may suggest structural changes to others who wish to avail themselves of the benefits of the invention, it is pointed out that subsequent modifications hereof may well be the same in spirit and principle as this disclosure.

The example of the invention herein illustrated, for

the purpose of demonstrating its principle and making claims to the inventive concept, comprises an electrical connector of the terminal class, and more specifically of the cord-plug species thereof, adapted to a two-wire fiat conductor. A study of my cord plug and its novel principles reveals that its construction and mode of operation may be utilized in single and in multi-wire terminals, as well as in electrical connectors of other classes.

Throughout the drawings, the front or inner end of this cord-plug connector is at the left-hand side, and the rear or outer end is at the right-the conductor entering at the rear end.

Sheet 1 of the oflicial Patent Office drawings (Figs. 1 through 5 thereof) is a repeat drawing of assembly views taken from my parent connector applicationXSer. No. 734,967) and brought forward to continue'herein, Fig. 6 being an added detail of the electrical-connecting barb there disclosed.

Fig. 1 illustrates what may be called the automatic" inner-wiring unit or core of the core plug in the act of being wired or attached to a longitudinally-joined twowire fiat conductor. The wiring core comprises ahard body of molded insulation halves carrying two pivoted automatically a pressure electrical connection with the wire strands and simultaneously establish a clamping or snubbing strain-relief grip upon the insulation, hence a dual or two-in-one connection with the conductor.

Fig. 2 shows a covering cap in perspective, also of hard molded insulation, which slips over the wiring core after its blades are closed to complete the cord-plug assembly, and to maintain the dual connection (electrical and mechanical) between the plug and its wire.

Fig. 3 shows the contact blade pair closed to make permanent electrical connection with the wire, but the cap (in lengthwise section) is pushed only part way onto the wiring core.

In Figs. 1 and 3, the upper half of the molded body is omitted from the views in order to' observe the automatic action of the wiring core.

Fig. 4 is a front end elevation of the assembled cord plug with the cap in place on the wiring core, and the Ifront end of the two-wire conductor being shown in dotted mes.

Fig. 5 is a longitudinal side section of the complete cord plug, without its wire. This view is made on the line numbered 5 in Fig. 4 locating the plane of section, thus breaking away the near side wall of the covering cap which is in final position on the wiring core, the two-part body of the latter appearing in side elevation.

Fig. 6 shows a detail of one of the contact blades, as taken on the section line numbered 6 in Fig. 1.

The drawings and description to follow continue with the structure of my parent appllication (Ser. No. 734,967) and also take up the present improvements. The individual parts shown in the parent application are of such similarity to my present improvements, as to make feasible their joint treatment, with a final explanation of their distinctions by the use of contrasting reference or part numbers on the drawings.

The views on Sheets 2 and 3 of the official original Patent Ofiice drawings are dimension-scaled and drawn from a commercial specimen of the electrical connector of the cord-plug species now on the market and shown three times its actual size in order to bring out details of the,

small size parts.

Fig. 7 is a perspective view looking at the inside face of one of the metallic electrical-conductive members having an electrical-connecting barb integral therewith of a form which differs from the barb on Sheet 1.

Fig. 8 shows the initial step of assembling the cord plug on a wire conductor. have been opened by hand. the wire inserted through the rear end of the detached cap, and all the way into the wiring core past its two open barbs. Swinging the two blades apart by hand is a feature of the present invention, and this view is important in illustrating a novel hold-open means for the pivoted blades, to steady them in open position as shown.

The similarity of my two cord plugs herein is apparent. However, one striking contrast is now made by comparing Fig. l and Fig. 8. The pivoted blade or lever means of my parent cord' plug (Sheet 1) automatically opens by thrusting the end of a wire into it, whereas my present cord plug (Sheets 2 and 3) requires that the lever means be swung open by hand. 7

Fig. 9 shows the completion of the manual assembly of the cord plug and wire initiated in Fig. 8, the two blades having been closed by thumb and forefinger pressure. Observe that the piercing position of the two barbs is shown'in dotted lines.

Fig. 10 is an action view demonstrating the operation of a latching detent means which locks and unlocks the wiring core to and from the cap. It is observed that thumb and forefinger pressure flexes the contact blades toward each other, as in the case of releasing and removing the cap preliminary to attaching the plug on a wire end, and also in the less likely case of detaching the plug from its wire.

The pivoted contact blades The next two views are transverse sections, looking toward the rear end, as per the direction of the arrows at the like-numbered sectional-viewing lines on Fig. 9.

Fig. 11 is a section on the line 11 through the two latching detent means at the front end of the plug.

Fig. 12 is a section on the line 12, near the center of the plug, showing the action of the two barbs piercing the insulation-covering, impaling the compacted strands of the two wires, and thus establishing a permanent pressure electrical connection therewith, as well as applying a strain-relief grip.

The description is continued by referring to the separate elements'of the foregoing two new combinations by reference numbers consistently applied to the same parts in all the views. Nonessential and conventional parts need not be numbered.

My earlier parent cord plug (Sheet 1 only) and the present improvements thereover (Sheets 2 and 3) are described together--using the same reference part numbers on both-where the features of the two inventions are common with each other. However, in order to point out features and parts which are novel and thus distinguish in their inventive concept, reference numbers in the thirty (30) series are used at the points of novelty on Sheets 2 and 3 in the following description.

Both new cord plug connectors herein comprise a pair of identical or twin conductive members in the form of contact blades carried by a body and its covering cap made of hard dielectric material. All three of these elements bear changes in their construction in the present invention, Sheets 2 and 3, and thus produce a combination new over that shown in Sheet 1.

The electrical-conductive member, its features, and. two forms of its barb A detail description is first given of an electricalconductive member (barbed-blade), two of which are requircd to produce this cord-plug connector. The present example is represented by the cord plug summarized in the foregoing general explanation of each view in the drawings, beginning with Sheet 1 showing my earliercase (Ser. No. 734,967), while Sheets 2 and 3 show my present improvements in said barbed-blade.

The two barbed-blades make a permanent pressure electrical connection with a covered wire CW-piercing its insulation covering C and impaling the compacted copper strands of a wire W, being a longitudinally-joined two-wire conductor, one barbed-blade for each stranded parallel wire-and also applying a double strain-relief grip, that is, two compression or squeeze grips on the insulation covering C.

Such contact blade is of elongated form, with parallel edges, and has a straight front end 3 (the terminal portion) of conventional shape and size. The front end 3 of the blade is thus adapted to engage, that is, to plug in and pull out of quick disconnect contact relation with an electrical outlet receptacle in the usual way for transmitting current to the covered conductor CW on the end of which the cord plug is permanently attached as a terminal. The other or rear end portion of the blade (housed within a body later described) is deformed by an offset at 4 to provide a strain-relief clamping shoulder 5 disposed inward of the blade. The shoulder 5 is syrnmetrically notched (see Fig. 7) on each parallel edge to provide two axially aligned trunnions or pivots 6 at the rear extremity of the blade.

The two trunnions 6 are square due to being die-formed from flat bar-stock, but all four trunnions of the two blades balance and pivot satisfactorily without wear in their socket bearings of cylindrical form molded in the body; This is due to the very limited movement required of the blades and their single-stroke action involved in permanently attaching the cord plug on the end of the covered wire CW. The two trunnions 6 of each blade are formed outward from the inner surface of the two identiward toward the rear end of the blade and merges with the outer face thereof. The front end of the detent boss 7 presents a blunt or square shoulder perpendicular to the face of the blade3, while the rear end of the boss feathers inwardly, wedge-like, to the blade face. As already observed (although later described), this detent boss 7 looks acovering cap on the wiring core of the cord plug.

An electrical -connecting barb 9 of straight-shank form (Sheet 1 only) is made on one edge of each pivoted contact blade 3, back near theoffset 4. This gives the front end of thecontact blade 3 about three times more length than the distance between the trunnions 6 and the piercing tip of the barb. Such relation provides for an approximate three-to'one leverage or mechanical advantage, over the barb 9, when applying a manual operating force at the front end '3 of the blade (see action view, Fig. 10). This is an important feature which makes for ease and convenience when attaching the plug onto the conductor CW, especially so'where the insulation covering C thereof has a tough skin and resists piercing.

The straight barb shank 9 with its sharp piercing tip may be die-formed integrally with the blade3 by cutting one edge thereof, as shown, and bending the cut portion inward in the same direction as the clamping shoulder 5. The length of the straight-shank barb 9 extends its cutting tip inward somewhat further, from the inside face of the blade, than the position of the clamping shoulder 5. It is seen that the shank 9 (Sheet 1 only) is of straight formbeing perpendicular to the blade 3and hence differs from my present barb (Sheets 2 and 3) as regards the curvature of the latter in relation to the axis of the trunnions 6, as described at the end of this topic.

Sheet 1 is of further importance in showing the shank form of my earlier barb 9. The cross sectional shape of the barb shank there disclosed is uniform in size from its piercing tip all the way back to the blade 3. Such characteristic in barb shape acts to make an unusually effective pressure electrical connection permanently maintained with the tightly compacted copper wire strands W. The initial tightness of the pressure connection is maintainedwithout the slightest drop (lessening) in pressure grip of the impaled strands spread apart and compactly embracing the barb shankin the event of slight retraction, that is, spring back or minute "give of the barb, or of fatigue in any of the connector parts, which may occur after being attached to the conductor CW by virtue of the electrical connection with the stranded wire W and the strain-relief grip on the wire covering Csimultaneously effected by each blade.

On the other hand, an arcuately-shaped electrical-connecting barb 30 ( Sheets 2 and 3 only) constitutes one of my present improvements having functional advantages over the earlier straight-shank barb 9 (Sheet 1). In other words, the arcuate barb 30 is a feature of the present invention-in that this particular barb is curved on a radius, the center of which is slightly eccentric t the pivot axis 6 and thus approaches a concentric relation therewith.

Accordingly, the are of circumference of the barb shank 30 is off-center from the trunnion axis 6 just enough to cause the tip portion of said shank to frictionally rub or slightly bind against a molded portion of the body (a friction boss within the body later explained) after the blade, that .is, after both blades are manually opened, as in Fig. 8. The purpose of providing this eccentricity near the piercing tip portions of each barb 30 is to make the blades stand alone and thus hold open and remain steady when inserting the wire CW into the wiring core. This feature is previously treated in the-preliminary description of Fig. 8, and it is also hereafter referred to in describing the operation ofthe wiring core.

The shank of thebarb 30 is also of uniform cross section, at its stranded wire engaging portion (compare Figs. 9 and 12), after the fashion and principle of the barb 9 (Sheet 1).

differ in their directional reach inward from the blade.

From the foregoing, it will be understood that two different structural forms of piercing barbs are shown for the blade 3. The earlier barb 9 has a straight shank, while my presentbarb 30 has an arcuate shank, and both possess a characteristic parallel-sides uniformity or a sameness of cross sectional size from their piercing tips back to the blade 3.

The present arcuate barb 30 is preferred, by reason of i the fact that its segmental shape-having ,a modified radial relation to the trunnion axis 6augments piercing entry through the insulation covering C. Also, the armate barb shank 30 acts with maximum effectiveness in spreading the compacted wire strands W, in order to pass The two-part body The body of the cord plug, which houses and pivotally supports or carries the two above described disconnectcontact blades 3, comprises two hard insulation molded half sections 11 of flat elongated and tapered form, being identical halves.

The two body halves 11 may be fittedtogether with the plane of their inner faces set in surfacetight abutment to each other, with well known centering dowelsto :aid in assembling the halves, andth'en cementing them to gether, as in Sheet 1. Or the two body halves 11 are riveted together in a known way, also employing dowels, as in Sheets 2 and 3. A unified housing or body 11 is thus produced by either conventional means for permanently fastening :two like halves together to form a whole body of fiat form. The conventional fastening means (dowels, holes and rivets)need not be numbered on the drawings. The molded body 11 is, therefore, one part of the wiring core and the two blades 3 the other.

The two bodys halves 11 may be substantially duplicate partsand thus are complementary to each other, that is, mutually interfitting. When joined together as shown, they provide a unified interior open space within the flat tapering body for operatively mounting the two contact blades 3, as well as for receiving the insulation-covered longitudinal-joined two-wire conductor CW. The two body halves 11 are of rectangular shape in cross section, with four flat rearwardly extending taper-reducing sides. Accordingly, the finished body 11 uniformly decreases (tapers) in size symmetrically from its large frontclosed end to its smaller rear open end.

Each body half 11 is molded with a single one-half lengthwise central wire-receiving passage 12 which opens through the'rear end thereof and extends to approximately the front end, where the passage is closed by a solid front end stop 13. When the two halves are joined together, it follows that a complete or unified wire-receiving single passage 12 is formed, with its dead-end stop 13 at the front end. The wire passage closely conforms in oval cross section to the fiat wire CW which has a close fit therein. The major cross sectional dimension of the wire CW is transverse to the plane of the width (greater dimension) of the flat thin body.

Thus, the two barbs are similar in their uniformity of shank cross-sectional size, from the, base of the piercing tip back to theblade 3, but they The interior of each body half 11 has an insulationsnubbing pocket 14 molded therein adjacent to and opening into the wire-receiving single passage 12 in a position to register with the tip of the swingable barb 9 or 30, as the case may be. When the two halves are placed face to face and joined, it follows that the two pockets 14 not only are on opposite sides of the passage 12 but that one pocket is up and the other is down in relation to and on opposite sides of the lengthwise axis of said passage. See section line 12 and Fig. 12 in reference to the staggered positions of these two strain-relief snubbing pockets 14 which grip opposite sides of the insulation of each half portion of the flat two-wire conductor CW.

A blade-friction portion on the body, in the form of a boss 31 (Sheets 2 and 3), is molded in each body half 11, perpendicular to the joined inner faces thereof, and also adjacent to the wire-receiving passage 12 (as seen by comparing Figs. 9 and 12). Each friction boss 31 and snubbing pocket 14 face each other across the wire passage. This position for the two bosses 31 places them on opposite sides of the passage when two body halves are joined together to complete the body unit 11, with its two pivoted blades 3, thus comprising the wiring core. Like the opposed position of the snubbing pockets 14, one boss 31 is up and the other down" in staggered relation to the wire passage 12, as shown in Fig. 12.

Two socket bearings 16 are formed in each body half 11, near the rear end thereof, spaced from the wirereceiving passage 12, and the four bearings pivotally receive the four trunnions 6 of the two blades 3 to provide for an equal and symmetrical swinging action of the blades to their opened and closed positions, as shown in all the drawings.

It is observed that the body 11 has a blade-receiving recess 17, grooved lengthwise in each of its narrower sides, from the front end and extending rearward for about two-thirds of the length of the body, one groove for each blade 3. Each groove portion of the recess 17 has its depth defined by a continuous curve approaching each other and symmetrically increasing the depth of the two grooves as they extend forward to the larger end of the body 11. The minimum depth of each groove portion 17, at each boss 31, should be equal to the thickness of thebar-stock of the blades 3 in order that both blades may lay flush with each side face of the body.

A clamping-shoulder receiving aperture 18 opens through the rear end of each side groove portion 17 and into the single wire passage 12 of the interior of the body 11. The two apertures 18 are of the same width as the two groove portions 17. They are rectangular or square shaped apertures 18 formed in the two narrow sides of the body 11 and are in symmetrical transverse alignment with each other therethrough. Each aperture receives the movable clamping shoulder of each swingable blade 3, and such shoulder protrudes part way into the wire passage 12, thereby intercepting it sufliciently to apply clamping or snubbing compression against the insulation C of the wire therein.

Next, a barb-receiving opening 19 also is formed through each recess groove portion 17 on each narrow side and into the interior of the body 11, but each barb opening 19 occupies only one-half the width of said groove. The two barb openings are formed on the same side of the wire-receiving passage 12 in each body half 11. Accordingly, when the two body halves are joined face to face, the two barb openings 19 are on opposite sides of the wire passage, and moreover one barb opening is up and the other is down" in relation to the axis of the passage.

The rear end of each body half 11 is serrated to form insulation-snubbing teeth 32 ( Sheets 2 and 3 only) symmetrically on both sides of the wire-receiving passage 12 transversely to the longer dimension across said rear end. When two body halves are fitted together to make a complete body 11, it follows that the four sets of snubbing teeth 32 provide two sets thereof on the rear end of the body. These snubbing teeth extend parallel with each other, one set on each side of the wire passage, in order that the wire CW resting crosswise of one set or the other of the teeth is gripped thereby, as further explained.

The two spaced and independent sets of insulationsnubbing teeth 32 on the rear end of the body 11 are presented as a feature of the present invention. The one or more clamping teeth 32 of each set form a clamping seathaving a gripping edge or ridged surface-against one or the other of which the wire insulation C is compressed with a strain-relief grip, thereby securing the conductor CW in the cord plug at an angle to the contact blades 3.

The covering cap for the body and wiring core A hollow cap 22 for covering and embracing the wiring core of the cord plug is first shown in my parent application (Sheet t1), and further improvements thereon are shown in Sheets 2 and 3 of my present application. Like the body 11, this cap also is molded of hard insulation. I

It is seen that the cap 22 in all the drawings is of rectangular shapein cross section, being of tapered hollow formation, open at its front end, of equal length with the tapered body 11, and made for a sliding !fit thereon back and forth in the direction of the length of the wirereceiv-ing single passage 12. A pair of oppositely disposed detent notches 23 is formed near the front end on the interior of the hollow cap. These two notches 23 ride over, register with, and snap latch upon the two yieldable detent bosses 7 under flex-nre of the contact blades 3, thereby locking the cap on the wiring core, covering the body, and maintaining the blades 3 in tightly closed position.

The rear end of the cap 22 is closed by a wall 24, through which a wire-entry hole 25 (Sheet 1 only) is provided in coaxial relation with the wire-receiving passage 12 of the body. Thus a covered conductor CW is passed through the center rear end of the covering cap 22 and straight into the wire passage 12. The conductor CW, therefore, enters the passage on a straight line and parallel with the blades 3, as in Sheet 1.

However, the covering cap 22 is more effective when made with the present improvements ( Sheets 2 and 3 only) by providing an off-center or offset wire-entry hole 33, which is not coaxially aligned with the wirereceiving passage 12. Compare the position of this new offset wire hole 33 with the earlier center hole 25 (Sheet 1) and contrast the difference in function.

Thus, it is seen that in my present invention, the conductor CW is kinked or bent over and against the rear flat end of the body (and across one or the other set of its snubbing teeth 32) as the wire passes through the offset wire-entry hole 33 of the cap and enters the wirereceiving passage 12 of the body at an angle to the blades 3. Good strain-relief anchorage of the wire in the cord plug is also attained by the offset wire hole 33 alone, that is, without the jaw-like teeth 32.

Further as to the cap 22, it isseen that one set of Since the end of the wire CW is first threaded through,

the offset hole 33 of the cap, it makes no difference whether the cap is placed with its one set of snubbing teeth 34 up or down, one way or the other, on the wiring corefor the reason that the rear end of the latter (the body 11) has companion snubbing teeth (one set thereof) on each side of its offset wire-entry hole '33.

and entry hole 33-is adequate to anchor the wire against pull-out from the cord plug without employing the jawlike teeth 32 and 34. Thus, the snubbing teethimay be omitted and the serpentine grip relied upon in either position (up or down) of the olfset entry of the wire CW through the side rear aperture or opening '33 of the cap 22 and into the wiring core embraced thereby.

Assembly and mode of operation The foregoing description makes clear the operatin-g tit and relation of the parts. It is seen that the four trunnion pivots 6 of the contact blades 3 are confined in their molded socket bearings 16, with the result that the two blades have an equal closing and opening movement at the front end of the body. Also, the two blades swing into closed position against the narrow sides of the body -11, flush with its outer surface, and nest within the grooved recesses 17.

When the two blades 3 are at normal parallel position inward against the body =11, within their close-fit grooves 17, it is seen that the inner faces of the blades come to rest against their respective bosses 31 act-ing as close-fit stops. This places a limit on further inward movement of each barb 30. in other words, the two bosses 31 stop the piercing tips of the arcuate barbs 30 at a position inward of the two insulation-snubbing pockets 14. (See Figs. 9 and 12.) This arrangement permits free ilcxure of the blades 3, within their respective recesses 17, that is, along their front end portions from the bosses 31 forward. (See act-ion view, Fig. 10.) Also, this feature causes the piercing tips of the two barbs 30 to expand or bulge the far sides of the insulation-covering C into the two opposite pockets 14 and thereby apply a double strain-relief grip on the flat wire at the two barb tips.

The body 11 of my parent application (Sheet 1) also has bosses 20, one molded on each body half. The bosses tend to limit the inward swing of the barbs 9, and also tend to provide flexure of the blades, within the body recesses 17, from the point of rest on each boss, forward to the front ends of the blades.

In my earlier cord plug (Sheet 1), the insertion of the conductor CW into the wire-receiving passage 12 automatically acts to swing the pivoted disconnect-contact blades 3 into open position. In other words, the end of the conductor is manually thrust against the two clamping shoulders '5, thereby spreading them apart to initiate the opening action, and then against the two barbs 9 (Sheet 1 only) to complete that action, thereby causing the blades automatically to swing outward on their pivots. This action opens or clears the passage '12 for tull entry of the conductor until its end passes the baths 9 and bottoms against the dead-end stop -13 at the front end of the wire passage.

On the other hand, the barbs 30 (hence the contact blades) of my present invention (Sheets 2 and 3) must' be manually opened. Inserting the conductor CW into the wire passage 12 does not automatically swing the barbs to their full opened position. This mode of operation is due to friction or binding engagement between the two friction bosses 31 and the portion of the barbs 30 near their piercing tips. This is observed in Fig. 8 where the tip of each barb 30 binds against its respective boss 31 and thus prevents 'full automatic opening action by thrusting the conductor into the passage 12.

However, once opened manually, the blades 3 hold open by reason of the foregoing provision. Such fea ture may be a convenience, in a way, when attaching the cord plug to its conductor. Inother words, the barbs 30 are positively held outward and away from the wirereceiving passage l2-and likewise the blades stand in steady open position-when the wiring core is held, in one hand and the wire is inserted thereinto by the other hand. The major portion of the. arcuate barb shank 30 has clearancebetween it :and the boss 31, asseen in Fig.

9,- and-is concentric with its pivot 6.-.in order to effect wire-receiving passage 12 perpendicular thereto and in the plane of each stranded wire W of the two-wire con- ,ductor CW. Thus the barb first pierces the near side of the insulation C, and then impales the wire strands, usually without piercing the far side-so that the latter side bulges into the snubbing pocket 14. When the barb is impaled on the wire, the strands W thereof separate and extend around each side of the. barb (see Fig. 12) with a compacted grip and permanently enduring pressure connection, as heretofore described with reference to the shape and form of each barb 9 and 30.

Next, it is observed that the clamping shoulders 5 of the swingable blades 3 extend through their respective body apertures 18 and partially intersect the wire passage 12 by protruding thereinto, said shoulders urging toward each otherwith a jaw-like action. This arrangement insures that when the two blades 3 are swung into final closed position (Fig. 3, also Figs. 9 and 10) the two clamping shoulders 5 apply a compressive strain-relief grip against both sides of the wire covering C and thus anchor the wire in the body at a distance spaced from the position of the barb 9 or. 30 impaling the wire strands.

From the foregoing it is now apparent that several compression-snubbing actions are applied by the unique operating means of the cord plug against the insulation covering C, by which to securely anchor a conductor CW in the plug to provide an unusually high pull-out value. First, the barbs 30 clamp and sung the wire insulation in the body pockets 14, and second, the clamping shoulders 5 apply a clamping action to the insulation remote from the point of barb piercing, as well as third, where it is seen (Sheets 2 and 3) that the offset wire-entry hole 33 type of covering cap grips the conconstitutes the invention or discovery, as understood by a comparison thereof with the prior art.

This invention is presented to fill a need for a new and useful electrical connector. Various modifications in construction, mode of operation, use and method, may and often do occur to others, especially so after acquaintance with an invention. Accordingly, it is to be understood that this disclosure is exemplary of the principles herein and embraces equivalent constructions.

What is claimed is:

1. An electrical connector comprising, in combina tion, a body formed with a passage adapted to receive an insulated two-wire conductor; and a pair of metal connector elements swingably mounted in the body for movement relatively to the passage, each swingable element having a piercing point extending therefrom toward the passage and in the plane-of movement of the swingable element; the planes of movement, of the piercing points beingspaced and parallel, the passage having its greater transverse dimension perpendicular to the plane of movement of the points and its lesser dimension sub stantially equal to the thickness of the insulated two-" wire thereof.

2. An electrical connector, as described in claim 1, and wherein the body is provided with a pair of recesses, one on each side of the passage and communicating therewith, each swingable connector element being disposed in one of the recesses and lying flush with the surface of the body when in closed position, a cap slidable onto the body over the closed swingable elements, and a latching-detent means provided on the swingable elements and the cap which secures them together.

3. An electrical connector, as described in claim 1, and wherein the body is elongated in shape and rectangular in cross section, with a lengthwise recess formed on Opposite sides, the passage extending between the two recesses, and each recess sloping inward toward the axis of the passage at the front end of the body, with one swingable element disposed in each recess and having extremities projecting beyond one end of the body to form disconnect-contact blades adapted to engage an electrical receptacle, a latching boss on the outer surface of each swingable element, a cap slidable onto the body over the swingable elements, and latching notches within the cap which engage the two bosses to fasten said cap on the body, the sloping recesses admitting of flexure of the blades toward each other to latch and unlatch the bosses with and from the notches.

4. An electrical connector, as described in claim 1, and wherein the two metal connector elements are arranged one on each side of the passage and are swingable toward and from each other, and a clamping shoulder is formed on each metal connector element and disposed inwardly toward the passage, in spaced relation from each piercing point, said shoulders being movable into the passage, thus applying a strain-relief grip upon both sides of the insulation of the conductors simultaneously with the piercing and the making of the electrical connection by the points.

5.An electrical connector as defined in claim 1 and wherein each piercing point is formed on a shank of arcuate shape and has a radial relation with the pivot on which the swinging movement takes place, and'friction means acting on the shank near the piercing point to hold it in outward pivoted position.

6. An electrical terminal of the cord plug type, comprising, in combination, a body having a single passage adapted to receive a flat insulated two-wire conductor; and a pair of metal connector elements, in the form of disconnect-contact blades, the front ends of which extend outwardly from the body, and the rear ends swingably mounted therein for movement relatively to said single passage, a piercing barb on the rear end portion of each swingable blade and extending toward the other blade as well as toward the passage and in the plane of the swinging movement, the plane of movement of each piercing barb being spaced and parallel and intersecting a respective wire; the passage having its greater transverse dimension perpendicular to the parallel planes of movements of the two barbs, and its lesser dimension substantially equal to the thickness of the insulated two-wire conductor lying along the passage; said blades being swingable from an open position, in which the insulated two-wire conductor may be inserted into the passage, to a closed position toward each other, and in which each barb intersects the passage, thus piercing the insulated two-wire conductor and making electrical connection with the respective wires thereof; and a cap provided with a wide-open front end, with an aperture at its rear end through which the conductor extends, said wide-open front end of the cap being slid onto the body from its rear end, and forwardly into final position thereon, thus embracing said body and its closed blades, thereby hold ing said blades straight-out from said body and maintaining the electrical connection.

7. An electrical terminal of the cord plug type, as defined in claim 6; wherein the cap has a pair of oppositely formed notches on the inside thereof, which are spaced back from its front end; and a boss on each swingable blade, in position to engage each of the notches, after the cap is in final position, thereby providing a detentlatching means concealed by and within the cap.

8. An electrical terminal of the cord plug type, as defined in claim 6, wherein the body has at least two elongated flat and opposite outer sides, with a lengthwise groove formed in each of said two opposite outer sides, and each groove sloping inwardly at the front end of the body toward the axis of the single passage, with each swingable blade of the pair nested within each sloping groove, a boss on the outer surface of each swingable blade, a pair of oppositely formed notches on the inside of the cap in alignment with the bosses, and said sloping grooves providing clearance spaces in which the front ends of the blades may flex away from and toward each other to latch and unlatch the bosses with and from the notches.

9. An electrical terminal of the cord plug type, as defined in claim 6, wherein a clamping shoulder is formed on each swingable blade, inwardly toward the single passage, in spaced relation from each piercing barb, said two shoulders being movable toward each other into the single passage, and thereby applying a strain-relief grip upon the opposite sides of the insulation of the flat twowire conductorwithin said passage, doing so simultaneously with the piercing electrical connection made by the barbs.

10. An electrical terminal of the cord plug type, as defined in claim 6, wherein a shoulder is formed on each swingable blade, inwardly toward the single passage, in spaced relation from and to the rear of each piercing barb, said two shoulders being movable with the blades toward each other into the single passage, and into the path of the conductor received thereinto, the end of the conductor striking against the shoulders as said conductor is thrust into the single passage, and acting to push the disconnect-contact blades outwardly to their open positions, thus retracting the two piercing barbs from the single passage, and permitting the conductor to be thrust beyond said barbs.

, 11. An electrical connector of the cord plug type, for use with a flat insulation-covered parallel longitudinallyjoined two-wire conductor, comprising a molded body having a single wire-receiving passage of cross-sectional size making a close fit with said fiat conductor adapted to be received therein; a pair of parallel contact blades swingably mounted within grooved recesses of the body on respective pivots, and projecting forwardly from said body, a barb on each blade, each barb intersecting the single passage in the plane of a respective wire; a stop formed on the body adjacent each barb against which its respective blade rests; and a cap slidable onto the body, over the blades, and clamping them between the stops and said cap, by which the blades may flex in their grooved recesses, forwardly from the stops, the flexing strain being exerted on and taken up by the stops; and latching means cooperating with the blade portions and with the cap forwardly of the stops for detachably securing the latter on the body.

12. An electrical connector of the cord plug type for use with a flat insulation-covered parallel longitudinallyjoined two-wire conductor, comprising a molded body, having a single wire-receiving passage of cross-sectional size making a close fit with said fiat conductor adapted to be received therein; a pair of contact blades pivoted within the body, an arcuate barb on each blade intersecting the single passage, the arcuate barbs being formed eccentric to their pivots, a portion on the molded body adjacent the barbs against which they bind when the blades are pivoted outward from the body, due to their eccentricity, by which the blades remain steady in open position; and a cap slidable onto the body, and over the blades, to hold the barbs in said intersecting position.

13. An electrical connector comprising, in combination,

a 13 a cap, a blade carrier embraced in said cap, said blade carrier having a passage adapted to receive aflat insulationcovered parallel two-wire conductor, a pair of contact blades mounted on said blade carrier and swingable relatively to said passage, each swingable blade having a piercing point extending therefrom toward the passage and in the plane of movement of the swingable blade; the planes of movement of the piercing points being spaced and parallel, the passage having its greater transverse dimension perpendicular to the plane of movement of the points and its lesser dimension substantially equal to the thickness of the insulated two-wire conductor lying along the passage, whereby each wire is in the plane of movement of each point; said blades being swingable from'an open position, in which the two-wire conductor may be inserted into the passage, to a closed position, and in which each point intersects the passage and pierces the insulated two-wire conductor, and the cap aforesaid holding the blades in said closed position, thus making electrical connection with each wire thereof.

14. An electrical terminal adapted to connect with a current supply, and including a body with a single wire receiving passage to receive flat insulation-covered wires, connecting means comprising electrical-connecting insulation-piercing barbs extending into the passage in the plane of the respective wires, the body having recess means; lever means pivoted in the recess means, lying flush with the body, and having clamping shoulder means adjacent the pivot, the clamping shoulder means also extending into the passage; the lever means and the clamping shoulder means being swingable freely in respect to the body and away from the recess means to admit the insulation-covered wires into the passage, and swingable by hand pressure back into the recess means and into said flush position, and thus into compressing engagement with the wires in said passage, to apply compression relatively between the insulation-covering and the barbs, thus causing the insulation on the wires to be pierced by the barbs, thereby effecting an electrical connection between the wires and barbs as well as placing the clamping shoulder means in simultaneous engagement against the insulation-covermg. V

15. An electrical connector adapted for use with a flat insulation-covered parallel two-wire conductor, comprising a molded body, having a central passage of crosssectional size making a close fit with said flat conductor adapted to be received therein, a pair of contacts mounted on the body, connecting means carried by each contact for electrically connecting a respective wire thereto; a cap slidable onto the body, having an aperture forming a misaligned extension of the central passage, and said passage thereby having an angular bend at the outer end and on end of the single central passage, and forming with the latter an angular bend to make a single passage which is tortuous; whereby the cap may he slid onto the body,

one side of the body, the passage and its angular bend being completely formed after the cap is slid onto the body in final position, the cap in said final position engaging the flat conductor at said angular bend and kinking its two wires thereat away from said central passage and on said one side of the body, the cap also engaging the connecting means to maintain each wire connected to its contact; and detent-latching means provided on and projecting outward from each contact, and coacting detentlatching means in the slidable cap, in a position which is back from one end of said cap, and in a concealed position, said co-acting detent-latching means detachably latching the cap and body against separation.

16. An electrical connector adapted for use with a flat insulation-covered parallel longitudinally-joined twowire conductor, comprising a molded body, having a single passage centrally formed therein and of crosssectional size making a close fit with said flat conductor adapted to be inserted into the entry end of said passage; a pair of contacts mounted within the body, means carried by each contact for electrically connecting a respective wire thereto; a closure cap slidable onto the body, and

a wire-entry hole formed in said cap, ofiset from the entry with said ofiset wire-entry hole disposed in. a position olfset sidewise in either of two directions of the entry end of the single passage, thus forming the tortuous single passage aforesaid, by which either position of the cap subjects the conductor to angular compression for establishing a strain-relief grip thereon.

17. An electrical connector comprising a body with a single passage for receiving a conductor, said single passage having a wire-end stop against which comes to rest the extremity of a flat insulation-covered parallel longitudinally-joined two-wire conductor, a pair of contact elements carried by the body, and each contact element having a barb extending into said passage, perpendicular to the fiat sides of the conductor, said barbs and two-wire conductor being compressible together to make a pierced electrical connection between each respective wire and a said barb; and electrical connecting and clamping means pivoted on the body, and closable into said passage, thus into the path of the conductor being thrust thereinto, and clampingly closable upon the conductor in said passage; the said pivoted electrical connecting and clamping means having an automatic opening motion, away from said passage to an outer position, by manually thrusting the conductor extremity into said passage against said electrical connecting and clamping means when pivotally closed into said passage; the said pivoted electrical connecting and clamping means, when automatically opened, permitting movement of the conductor to the wire-end stop, the said pivoted electrical connecting and clamping means being manually swingable back for forcing it into closed position in said passage, thereby compressing the two-wire conductor and the barbs together and making said pierced el ctrical connection, and also applying a. strain-relief grip against the conductor insulation. 1

.18. An electrical cord plug, for a flat insulation-covered parallel longitudinally-joined two-wire conductor, comprising a body having a single passage adapted to receive the conductor, a pair of disconnect-contact blades having their inner ends mounted on the body, and their other ends extending from the body; a barb integral with each blade, and intersecting said passage, perpendicular to the flat sides of the conductor, the barbs and two-wire conductor being compressible together to make electrical connection between each respective barb and a respective wire of the conductor in said passage; and electrical connecting and clamping means pivoted on the body, and extending into said passage, in the path of the conductor being manually thrust thereinto, and automatically pivoted to an open position, by thrusting the end of the conductor against said electrical connecting and clamping means, the said electrical connecting and clamping means being pivotally forced back manually to a closed position, thus applying compression between the barbs and conductor and making said electrical connection, and also applying a strain-relief grip on the conductor insulation.

19. In an electrical connector plug of the self-piercing type, the combination of a housing of insulating material having an opening therein, a pair of contact-carrying members slidably mounted in said opening, said members having inner and outer faces with the outer faces thereof engaging with the sides of the opening in the housing and holding the inner faces thereof in opposing relation, said inner faces having recesses therein shaped to receive an unstripped end of a dual conductor cord between said members, each of said members having an opening ex-' projecting from one face thereof, said conductor-piercing 5 References Cited in the file of this patent UNITED STATES PATENTS 978,199 Phelps Dee. 13, 1910 1,752,662 Eckstein Apr. 1, 1930 m 2,158,922 Barnitz May 16, 1939 2,159,064

Walter May 23, 1939 16 Brainard May 19, 1942 Mattis July 18, 1944 Pollock Oct. 17, 1944 McLarn Apr. 29, 1947 Roche Oct. 21, 1947 Cook Sept. 27, 1949 Schroeder Dec. 19, 195" FOREIGN PATENTS Great Britain Apr..6, 1933 Great Britain July 3, 193

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