US 3858159 A
A connector for a multi-conductor flat cable having a plurality of insulated round wire conductors wherein contact elements nested in the connector are respectively connected to selected conductors of the cable, each contact element having a circuit connecting terminal and a bifurcated part nested within the connector. The bifurcated part provides a pair of pointed prongs the inner edges act to slice through the conductor insulation to electrically engage opposite sides of the conductor wire when the prongs are clinched together. The bifurcated part is so twisted or skewed relatively to the longitudinal axis of the insulated conductor as to provide the prongs with sharp cutting edges which respectively bite into and make contact with opposite sides of the conductor wire at two points spaced lengthwise of the wire. Means are provided in the connector for clinching the contact prongs into engagement with the conductor wire, which means act also to effectively maintain this clinched engagement. The twist or skew of the bifurcated part of the contact places the clinched conductor under tension in the region of its connection to the contact, the force of which tension serves additionally to hold the contact securely clinched to the conductor.
Claims available in
Description (OCR text may contain errors)
United States Patent Worth [451 Dec. 31, 1974 1 ROUND CONDUCTOR FLAT CABLE CONNECTOR  Inventor: Sidney V. Worth, Flourtown, Pa.
 Assignee: Continental-Wirt Electronics Corporation, Warminster, Pa.
 Filed: Aug. 10, 1973  Appl. No.: 387,485
 US. Cl. 339/99 R, 339/105, 339/176 MF,
339/17 F  Int. Cl H01r 9/06  Field of Search 339/95-99, 339/103l07, 176 MP, 17 F  References Cited UNITED STATES PATENTS 2,360,444 10/1944 Pollock 339/97 L 3,380,013 4/1968 Krone et a1... 339/97 P 3,434,093 3/1969 Wedekind..... 339/176 MF X 3,444,506 5/1969 Wedekind 339/17 F X 3,550,066 12/1970 Cootes 339/ 107 3,761,869 9/1973 Hardesty et al 339/49 R FOREIGN PATENTS OR APPLICATIONS 67,298 2/1951 Netherlands 339/97 R Primary Examiner-Roy D. Frazier Assistant Examiner-Robert A. Hafer Attorney, Agent, or FirmEdelson and Udell  ABSTRACT A connector for a multi-conductor flat cable having a plurality of insulated round wire conductors wherein contact elements nested in the connector are respectively connected to selected conductors of the cable, each contact element having a circuit connecting terminal and a bifurcated part nested within the connector. The bifurcated part provides a pair of pointed prongs the inner edges act to slice through the conductor insulation to electrically engage opposite sides of the conductor wire when the prongs are clinched together. The bifurcated part is so twisted or skewed relatively to the longitudinal axis of the insulated conductor as to provide the prongs with sharp cutting edges which respectively bite into and make contact with opposite sides of the conductor wire at two points spaced lengthwise of the wire. Means are provided in the connector for clinching the contact prongs into engagement with the conductor wire, which means act also to effectively maintain this clinched engagement. The twist or skew of the bifurcated part of the contact places the clinched conductor under tension in the region of its connection to the contact, the force of which tension serves additionally to hold the contact securely clinched to the conductor.
12 Claims, 9 Drawing Figures SHEET 2 BF 2 PATENTED DEB3 1 I974 This invention relates generally to electrical connectors and more particularly to connectors for multiple conductor insulated cables in the form of flat tapes having a plurality of longitudinally extending parallel insulated wire conductors secured together in a common plane by an enveloping film of plastic or other penetrable dielectric material.
Flat conductor tapes of the type described are a relatively recent development in the electrical conductor art and are commercially available in long lengths which can be cut into shorter lengths as required. The present invention provides means for making permanent electrical connection between any or all of the several insulated conductor wires of the cable and elec trical contacts having terminals through which the conductors of the cable may be electrically connected to the components of an electrical circuit.
It is important that the contacts applied to the several conductors of the cable tape be respectively in exact alinement with the conductors so that they may be permanently secured thereto without any electrical interengagement with adjoining ones of the closely related conductors of the cable tape. To this end, it is an important object of the present invention to provide a connector for the flat cable tape having a plurality of contacts which are supported in exact alinement with the closely related round wire conductors of the cable tape, each in non-interfering relation with respect to a conductor or conductors other than that to which a given contact is individually secured.
A further object of the present invention is to provide a metal bifurcated contact which is adapted to pierce the cable tape and be securely staked to the wire conductor in registry with the contact to provide a mechanically secure and low resistance connection be tween each contact and its associated conductor of the cable.
Still another object ofthe present invention is to provide a connector for a cable tape of the character described which may be employed in conjunction with such tapes having a low center to center distance between the several conductors thereof.
A still further object is to provide a contact having a pair of sharply pointed laterally spaced tines or prongs which pierce the cable tape and slice through the insulation of the conductor to which it is connected in such manner as to straddle and pinch therebetween the metal strand of the conductor, the conductor pinching prongs being so oriented relatively to the longitudinal axis of the conductor and constrained against separation as to impart thereto a tensile force which reacts to hold the contact prongs securely clinched to the metal stand of the conductor.
A still further object of the present invention is to provide a connector having nested therein a plurality of the aforesaid contacts, one for each conductor to be connected in circuit with an electrical component, which is adapted to provide a secure electrical connection between each said contact and its associated conductor without the necessity of using special assembly tools or jigs.
Other objects and advantages of the present inven tion will appear more fully hereinafter, it being understood that the invention consists substantially in the combination, construction, location and relative arrangement of parts, all as described in detail in the following specification, as shown in the accompanying drawings and as finally pointed out in the appended claims.
In the accompanying drawings:
FIG. 1 is a perspective view showing the connector of the present invention attached to one transversely cut-end of a flat conductor cable having therein a plurality of parallel insulated round wire conductors commonly enveloped in a sheath of dielectric material;
FIG. 2 is a greatly enlarged transverse cross-sectional view of the cable-attached connector as taken along the line 22 of FIG. 1;
FIG. 3 is a transverse cross-sectional view on a somewhat smaller scale than that of FIG. 2 as taken along the line 33 of FIG. 1;
FIG. 4 is a longitudinal sectional view of the cableattached connector as taken along the line 44 of FIG.
FIG. 5 is a partial sectional view as taken along the line 5-5 of FIG. 4;
FIG. 6 is a perspective view, greatly enlarged, of a contact element as constructed in accordance with and embodying the principles of the present invention;
FIG. 7 is an exploded view showing in perspective portions of the mating dielectric members of the connector between which the conductor cable is clamped;
FIG. 8 is a partial sectional view of one of said mating members as taken along the line 8-8 of FIG. 7; and
FIG. 9 is a perspective view ofa modified form of the connector contact element of the present invention.
Referring now more particularly to the drawings it will be observed that the connector of the present invention, designated generally by the reference numeral 10, is shown applied to a flat multi-conductor cable 11 of the type which includes a plurality of longitudinally extending parallel conductor wires 12 having insulation coverings 13 secured together in a common plane by an enveloping film of plastic, such as polyester or other penetrable dielectric material. The connector 10 which is clamped to the insulated multi-wire cable 11 crosswise thereof is in the form of an assembly which includes an elongated contact supporting base plate 14 molded or otherwise formed of plastic or other suitable insulating material which overlies one face of the flat insulated cable and a mating cover plate 15, formed also of the same material, which overlies the opposite face of the cable. The base plate 14 supports a plurality of contact elements 16 (such as are best shown in FIGS. 6 and 9) which are respectively mechanically and electrically connected to the several conductor wires 12 of the cable to which the connector is clamped.
As shown in FIGS. 6 and 9, the contact elements 16 are typically formed as stampings from a relatively thin but suitably hard and durable sheet metal, such as berylium or phosphor bronze. Preferably, the thickness of the stamped contact element is on the order of 0.0 l 2 inch but this thickness may vary within a range of from 0.0l0 to 0.025 inch as may be required for a particular guage of the conductor wire present in the insulated cable. The contact elements 16 are generally forkshaped, each having an elongated terminal stem 17 terminating in a widened bifurcated part 18 to provide a pair of laterally spaced sharply pointed prongs 19--19 which are conjointly adapted to pierce the cable, cut
into the insulation of an individual conductor and pinch therebetween the wire of the conductor. The terminal stem 17 may be of any suitable shape as may be required to serve as a terminal for connection to a printed circuit or other electrical circuit or component. Although the terminal 17 is shown elongated for projection externally of the connector 10, it may be ofa form and shape designed to be housed internally of the connector 10.
In the form of the contact element shown in FIG. 6, the widened part 18 thereof is notched or lanced to respectively provide its opposite side edges with tabs 20-20 which are bent out ofthe plane of said part 18 to serve as will appear hereinafter as a means for frictionally retaining the contact elements in the base plate 14 of the connector during the operation of fixedly anchoring the contact to the wire conductors of the cable clamped in the connector.
In the modified form of the contact element, as shown in FIG. 9, in lieu of the two side tabs 20-20 above described, its terminal stem 17a is provided with a single lanced tab 20a for frictionally retaining the contact element in the base plate 14 of the connector preliminary to its being fixedly attached to a wire conductor of the cable.
In accordance with the present invention, the bifurcated part 18 of the contact element 16 is angularly twisted some or so out of the plane of the contact terminal stem 17 as at 18 (see FIG. 6) or 18a (see FIG. 9) and preferably the pointed extremities 21-21 of its cable-piercing prongs 19-19 are respectively oppositely bent as shown for a purpose which will appear hereinafter.
The contacts are initially inserted with their flat terminal stems 17 extending foremost into a plurality of slits 22 respectively provided therefor in the base plate 14 of the connector 10. As most clearly appears in FIGS. 1, 4 and 7 these slits 22 are disposed in edgewise spaced relation along one or more rows thereof extending lengthwise of the connector base plate 14, i.e., transversely across the width of the cable clamped in the connector. Each of said slits 22 is provided with an upper section 26 which opens through the top of the base plate 14 and is of a dimension to more or less snugly receive therein the terminal stem 17 of one of said contact elements and with a lower section 24 which opens through the bottom of the base plate and is of an enlarged dimension sufficient to accommodate therein the relatively twisted bifurcated part 18 of the contact element. The two sections 23 and 24 of each slit 22, which are in communication with each other, thus conjointly extend through the full depth of the base plate and provide each slit 22 intermediate its opposite open ends with an internal shoulder 25 which is engageable by the relatively wide bifurcated part 18 of the contact element to limit the extent to which its terminal stem 17 projects externally of the slitted top surface of the connector base plate 14.
The several contact elements are respectively frinctionally held in the slits 22 formed in the base plate 14 by the retaining tabs -20 (see FIG. 6) or by the tab 20a (see FIG. 9). In the case of the contact element of the form shown in FIG. 6, its retentions tabs 20-20, when oppositely bent as shown respectively resiliently engage opposite walls of the enlarged lower section 24 of the slit into which said contact is inserted. If desired, these tabs 20-20 may be similarly bent in the same direction so as to resiliently engage only one wall of the slit 22. In the case of the contact element shown in FIG. 9, its single retention tab 20a resiliently engages one wall of the upper section 23 of the contact-receiving slit.
With the contact elements fully inserted into their respective slits formed in the base plate 14, it will be observed, as best shown in FIGS. 4 and 7, that the end portions of the cable piercing prongs 19-19 of the contact elements 16 all project freely beyond the cable engaging bottom surface of the base plate 14, and thus are in position to slice through the insulation of the cable for mechanical and electrical engatement with the wire conductors thereof in accordance with the procedure and in the manner now to be described.
It will be noted that the bottom surface of the base plate 14 through which the cable-piercing prongs 19-19 of the contact members project (as see FIG. 7) is centrally channeled or recessed, as at 26, to a depth less than the overall thickness of the cable so that when it is laid in the recess its bottom portion projects externally of the recess while at the same time the cable itself is held against sidewise shift by the shoulders 27 formed at opposite ends of the recess. The spacing of the contact-receiving slits 22 within the recessed portion of the base plate 14 is of course such that when the cable is laid into the recess 26, the cable-piercing prongs 19-19 of the several contact members nested in the slits 22 are respectively disposed in straddling relation to the several conductors of the cable, i.e., with the prongs of each contact member disposed in a plane which is perpendicular to the flat plane of the cable and is so oriented as to form an angle of about l0 with the longitudinal axis of the conductor to which the contact member is to be connected (as see FIG. 5). i
As has been indicated, the connector may be provided with one or more rows ofin-line contact members depending upon number and spacing of the conductor wires contained in the flat insulated cable. FIG. 1 illustrates a connector having two such rows of contact members, and in which the contact members of one row are staggered with respect to those of the other row, thereby permitting a given connector to have a high density of cable-connected contact members per unit length of the connector.
Securement of the several insulated conductors of the flat cable respectively to the contact members of the connector is preferably effected by use of the cover plate 15 in the following manner. As appears most clearly in FIGS. 4 to 8, this cover plate 15 is provided in the surface thereof which underlies the recess 26 of the base plate 14 with a plurality of parallel arcuately shaped grooves 28 suitably spaced along the length of the cover plate to respectively accomodate therein the several insulated conductors-of the cable 11 in such manner that when the base and cover plates are secured together the cable is effectively clamped therebetween. Also provided in the cover plate 15 are a plurality of cavities 29, one for each of the grooves 28, which extend crosswise of the said grooves for vertical registry respectively with the slits 22 of the base plate 14. Each of these cavities 29 is of a rectangular outline and so dimensioned as to receive therein the freely projecting portions of the cable-piercing prongs 19-19 of each contact member 16 nested in a slit 22 of the base plate 14. The opposite end walls of each cavity 29 are inclined downwardly and inwardly with respect to each other, as at 30-40, to provide in effect tapered cam surfaces which respectively engage the outer edges of and force together the prongs 19-19 of the contact member projected into the cavity. This camming action, which results when the grooved and cavitied cover plate is pressed or drawn tightly against the base plate 14, is facilitated by slightly rounding off or bevelling the outer edges of the pointed extremities of the prongs 19-19 to thereby provide for easier penetration of the prongs into and through the cable insulation and better sliding movement of the contact prongs along the tapered camming surfaces of the cavities 29 upon insertion thereinto of the prongs.
For securing the cover plate 15 flatwise against the base plate 14 and so clamp the cable therebetween, the flats of the plate 14 which define therebetween the cable accomodating recess 26 are respectively fitted with nuts 31 for threadedly receiving clamping screws 32 extending through suitable apertures provided therefor in the opposite ends of the cover plate. As the cover plate 15 is drawn tightly against the base plate 14 by the screws 32 threaded into their nuts 31 with the flat cable 11 disposed therebetween, the pointed prongs 19-19 of the contact members 16 nested in the base plate as aforesaid simultaneously slice through opposite sides of the insulation of each of the cable concluctors resting in the grooves 28 of the cover plate and cut into the conductor wire itself.
The prongs 19-19 of each contact member 16 thus straddle and effectively mechanically and electrically engage therebetween the conductor wire 12 which is to be connected to each contact member. This mechanically secure and low resistance connection between each of the cable conductor and its contact member is effectively obtained not only by the camming action of the tapered end walls of the cavity 29 upon the prongs 19-19 of the contact member for tightly clinching the latter to its associated conducto but also by the twist of the prongs relatively to the axis of the conductor which provides the latter with relatively sharp cutting or slicing edges 33-33 (see FIG. 5) which respectively bite into the opposite side of conductor wire. In addition, due to the fact that opposed edges of the prongs 19-19 which bite into opposite sides ofthe conductor wire clinched therebetween are offset lengthwise of the conductor, as see FIG. 5, while at the same time the prongs 19-19 are held restrained against separation from the conductor wire by interengagement of their outer edges with the tapered end walls of the cavity into which they project, the prongs 19-19 act to impart such twist or kink in the conductor in the immediate region of the clinched connection as to place it under tension in that region, thereby establishing a force which reacts as the conductor tends to straighten out to maintain the prongs 19-19 tightly closed against the conductor wire.
It will be noted that when the contact members 16 are respectively staked to the wire conductors of the flat cable as hereinbefore described, they remain anchored to the cable despite any loosening or even complete separation of the connector plates 14 and 15 from one another.
It will be apparent that other means and methods may be employed for respectively connecting the several contact members to the several conductors of the flat cable, such as by use of a press (not shown) which might include a bottom platen having grooves and cavities corresponding to those of the cover plate 14 for accommodating the cable conductors and the freely projecting prongs of the contact members nested in the base plate 14 during the operation of clinching the contacts to their conductors. Thereafter, it would only be necessary to secure the cover plate 15 to the base plate by any suitable means.
It is desirable to provide a strain relief for the conductor cable having the connector attached thereto and to this end the cable connector of the present invention is provided with a self-contained means for precluding the imposition of any strains or stresses upon the connections between the several conductors of the flat cable and their respectively associated contacts. Thus, it will be noted that the base plate 14 is provided along one of its longitudinally extending sides with a depending flange 34 which is spaced from the corresponding side of its associated cover plate 15 a distance equal to the thickness of the cable disposed therebetween. The end portion of the cable 11 which is clamped between the connector parts 14 and 15, as see FIG. 2, is preset, preferably prior to securement of the contact members to its conductors, to a shape which includes a Z-shaped portion 35 adapted to be snugly accommodated within the correspondingly shaped cable space formed between the flanged plate 14 of the connector and its cover plate 15. When the plate 15 is secured in covering relation to the cable, the Z-shaped bend in the latter serves to relieve the contact-to-cable conductor connections of strains and stresses which might be disruptive of the connections. In some instances, the Z-shaped form of the cable may be obtained simply by clamping the cable between the connector parts 14 and 15, thereby eliminating the step of pre-setting the cable to its Z-shaped form.
Also, as shown in the drawings the cover plate 15 is preferably provided along the side thereof which is opposite that which includes the strain relief flange 34 with a flange 36 which overlaps the corresponding side of the plate 14 and serves as a protective shield against exposure of the cut end of the cable to which the connector is attached.
Mention has been made of the fact that the pointed extremities of each pair of the contact prongs 19-19 are oppositely bent as shown in FIGS. 6 and 9. This is for the purpose of facilitating insertion of the angularly oriented prongs into their respective clinching cavities during the operation of initially connecting the contact members to their respectively associated conductors or when it is necessary to reassemble the mating members 14 and 15 of the connector after they had been sepa rated for any reason. By so bending the points of the contact prongs they provide in effect slopes which help to guide the prongs into the open ends of their accommodating cavities.
It will be apparent that various modifications and variations may be made from time to time without departing from the essential principles or real spirit of the invention and accordingly it is intended to claim the same broadly, as well as specifically, as indicated by the appended claims.
What is claimed as new and useful is:
1. An electrical connector for an insulated flat cable having a plurality of insulated round wire conductors disposed in coplanar side by side relation within an enveloping film of plastic or other penetrable insulating material comprising an insulated structure secured to the cable in transversely extending relation to the conductors thereof and a plurality of electrically conductive metal contact members respectively mounted in said structure crosswise of the longitudinally extending axes of the cable conductors, each of said contact members having a terminal part for connection to an electrical circuit or component thereof and a retention part internally nested in said structure, said retention part having an end thereof bifurcated to provide a pair of spaced-apart sharply-pointed prongs for piercing the cable in straddling relation to an insulated conductor thereof, said prongs having opposed sharply cornered cutting edges for slicing through the insulation and electrically engaging the wire of said insulated conductor, said conductor-straddling prongs of each of said contact members being disposed in a common plane so angularly oriented relatively to the longitudinal axis of the conductor wire engaged thereby that said sharply cornered cutting edges of the prongs engage and bite into the conductor wire at points offset from one another lengthwise of the conductor wire for imparting a bend thereto whereby to place it under tension in the immediate region of its engagement by said prongs, the end portions of said conductor-straddling prongs of each of said contact members being extended beyond the conductor embraced therebetween for conjoint clinching of said prongs against said conductor-wire en gaged thereby, and means in said structure for camming said prongs into their said clinched condition about said conductor wire, said camming means being operative to establish a force which reacts against the restrained tendency of the conductor to assume its straightened condition to thereby hold said prongs tightly engaged with the conductor wire.
2. A connector as defined in claim 1 wherein said insulated structure is provided with a plurality of contactreceiving pockets arranged in at least one row thereof extending transversely across the width of the cable to which said connector is secured, said pockets being disposed in spaced end to end relation substantially in a plane extending normal to the plane of the cable with said pockets respectively in vertical registry with the conductors of said cable to which said contacts are secured, said contacts being individually nested in said pockets and electrically connected to the conductor wires in registry therewith.
3. A connector as defined in claim 2 wherein each said contact member is provided with means for frictionally retaining the same nested within each of said pockets.
4. A connector as defined in claim 2 wherein each of said contact-receiving pockets is provided with an upper portion having an opening through which externally projects said terminal part of a single contact member and with a lower portion having a closed bottom in which is received the bifurcated end of said single contact member and wherein the wire conductors of said cable are clamped in said connector flatwise be tween the said upper and lower portions of said pockets with the bifurcated ends of the several contact members respectively spanning the several conductors of the cable.
5. A connector as defined in claim 1 wherein said insulated structure includes a multi-slitted base member and a mating multi-recessed cover member adapted to be secured together with the slits of said base member in vertical alinement respectively with the recesses of said cover member, wherein the opposed end walls of each of said recesses of said cover plate member are provided with oppositely tapered surfaces which respectively cam the prongs of each contact member nested in each of said recesses into clinched engagement with the conductor wire which extends transversely across each said recess, and wherein a multiround wire conductor flat cable is clamped between said base and cover members with the several conductor wires of said cable each having clinched thereto one of said contact members nested in said slits and their respectively alined recesses.
6. A connector as defined in claim 5 wherein said cover plate member is provided with a plurality of grooves extending transversely thereof in respective alinement with the insulated wire conductors of the cable to which said connector is secured, each of said grooves having associated therewith one of said contact-receiving recesses, whereby, when said cable is clamped between said mating base and cover members with the insulated wire conductors thereof respectively disposed in said grooves and extending across the recesses respectively associated therewith, the prongs of said contact members clinched to said wire conductors are respectively nested in said recesses of said plate.
7. A connector as defined in claim 5 wherein the extremities of the bifurcated end of each contact member are respectively turned inwardly of the cover plate recess in registry with the contact prongs to facilitate nesting of said prongs in said recess.
8. A connector as defined in claim 5 wherein one of said mating members of said insulating structure is provided along one side thereof with a flange disposed in spaced parallel relation to the corresponding side of the other of said mating members to form an angularly shaped space between proximate surfaces of the mating members in which to compressively receive a correspondingly shaped section of the cable and thereby provide a strain relief means for the cable clamped in said structure.
9. A connector as defined in claim 5 wherein said base and cover plate members of said insulating structure are complementally shaped lengthwise along one side thereof to protectively enclose a square-cut end of the cable clamped between said members.
10. An electrical contact element in combination with insulated round wire conductor of a multiconductor flat cable comprising a stamping of thin sheet metal which includes a bifurcated body portion having a pair of coplanar spaced apart pointed prongs angularly oriented relatively to the longitudinal axis of said insulated conductor and respectively engaging opposite sides of the conductor wire at two points relatively offset from one another along said axis, the opposed inner edges of said prongs having relatively sharp cutting edges which penetrate the conductor insulation and bite into opposite sides of the conductor wire whereby to place the latter under tension in the region of its engagement by said prongs.
11. The combination as defined in claim 10 wherein said conductor is disposed within the kerf of said bifurcated body portion of the contact element with the end portions of its said prongs extending freely beyond the periphery of the wire conductor and wherein said freely projecting end portions of said prongs are pinched together to force said prongs into firm and positive engagement with the conductor wire.
cated body portion of said contact element and wherein the pointed extremities of said prongs are oppositely bent to provide curved surfaces for leading said prongs into a receiving recess therefor.
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