Shielded Flat Cable Connector Assembly

Abstract

A connector assembly for shielded multi-conductor, flat cable wherein a connector housing is anchored through the cable matrix and shield material. The conductors are shielded, yet insulated from the shielding, in the connector housing as well as along the length of the cable.

Description

BACKGROUND OF THE INVENTION

This invention relates to a connector for multi-conductor flat cable. It deals more particularly with a connector for shielded multi-conductor flat cable.

Multi-conductor flat cable is now widely used in computer circuitry applications and the like. In order to prevent cross-talk in the circuitry; i.e., the unintentional transference of electrical signals, the cable is preferably shielded. Shielding normally comprises providing a layer or sheet of a conducting material in the cable as a ground plane. Representative of such shielded flat cables are a ribbon cable manufactured by Hughes Electronics Co., Inc., Los Angeles, Calif., and the wire cable No. 3338-1 manufactured by the 3M Corporation, Minneapolis, Minn.

A segment of shielded flat cable ordinarily terminates at opposite ends in connectors which join it to suitable components in a computer, for example. The connectors preferably provide shielding for the conductors and contacts within their confines to prevent signal transference between conductors.

With known connectors, however, tedious wire preparation of the individual conductors is normally necessary to make contact connections. Shielding is difficult and cumbersome. Furthermore, complicated and relatively expensive structure is necessary to provide strain release capabilities; i.e., strain transfer from the cable to the connector body structure without unduly straining the electrical connection.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved shielded flat cable connector assembly. Another object is to provide a connector assembly which affords simple, yet highly effective shielding of current paths within and without the connector housing. A further object is to provide a connector assembly which affords a reliable, low-cost connection between the connector contacts and conductors. It is still a further object to provide a highly effective strain relief capability which protects the connection of the contacts to the cable from stress applied to the cable or the connector.

The foregoing and other objects are realized in accord with the invention by providing a connector assembly including a housing which grips a cable between a cable nest and a cable cover. One end of the cable extends into the housing and the conductors are crimped to contacts therewithin, while the body of the cable itself is locked onto strain relief cable anchors. Shielding material extends into the housing and over the crimp connections and contacts to prevent signal transference or cross-talk. The housing members are locked together to retain the cable and the housing is apertured to receive terminal pins, for example, for engagement with the contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with its construction and method of operation, along with other objects and advantages thereof, is illustrated more or less diagrammatically in the drawings, in which:

FIG. 1 is a top plan view of a shielded flat cable and connectors embodying a first form of the present invention, with parts removed and one connector assembly in position to receive the pins of a direct-entry printed circuit board component;

FIG. 2 is a side elevational view of the cable connector assembly illustrated in FIG. 1;

FIG. 3 is an enlarged fragmentary view of one end of the shielded flat cable, with the connector assembly housing removed to illustrate contacts and contact connection;

FIG. 4 is a view taken along line 4--4 of FIG. 3, also illustrating separated connector housing components;

FIG. 5 is a sectional view taken transversely through the shielded flat cable of FIGS. 1-4;

FIG. 6 is an enlarged, exploded view of a portion of the connector assembly embodying features of the first form of the present invention;

FIG. 7 is a top plan view of the contact utilized in the connector assembly illustrated in FIGS. 1-6;

FIG. 8 is a sectional view taken along line 8--8 of FIG. 7;

FIG. 9 is a sectional view taken along line 9--9 of FIG. 7;

FIG. 10 is an enlarged fragmentary view similar to FIG. 3 illustrating another type of flat cable adapted for mating with a connector in an assembly embodying features of a second form of the invention;

FIG. 11 is a sectional view taken along line 11--11 of FIG. 10, also illustrating separated connector housing components;

FIG. 12 is a sectional view, similar to FIG. 5, through the flat cable of the type illustrated in FIGS. 10 and 11;

FIG. 13 is the bottom plan view of the cover member of the connector assembly housing utilized in both forms of the present invention;

FIG. 14 is a plan view of an insulator strip incorporated in the connector assembly embodying features of the first form of the invention;

FIG. 15 is a top plan view of the housing nest member adapted to mate with the housing cover member of FIG. 13;

FIG. 16 is a sectional view taken along line 16--16 of FIG. 13; and

FIG. 17 is a view taken along line 17--17 of FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and particularly to FIGS. 1 and 2, a shielded flat cable connector assembly embodying features of a first form of the present invention is illustrated generally at 10. The cable connector assembly 10 includes a section of shielded flat cable 11 terminating at its opposite ends in identical connectors 12. One of the connectors 12 is shown about to receive the terminal pins 15 of a direct-entry, printed circuit board header 16 of conventional construction.

The shielded flat cable 11 is of the stranded wire type manufactured by the 3M Corporation of Minneapolis, Minn., and hereinbefore referred to. The cable 11 includes, as seen best at FIGS. 3-5, a flexible matrix sheet 20 of insulating plastic material. Embedded in the matrix sheet 20 in longitudinally extending, parallel, spaced relationship, are a series of stranded conductor wires 25a and 25b.

The conductors 25a are spaced across a greater portion of the width of the matrix sheet 20 and disposed adjacent the upper surface of the sheet, although embedded in it. A single conductor 25b extending adjacent one edge of the sheet is embedded further into the matrix so that it comes into electrical contact with a wire-mesh grounding shield 26 also embedded in the matrix sheet 20 and extending substantially across its width. As will be noted, the conductors 25a are spaced from the wire-mesh grounding shield 26, the shield lying entirely on one side of these conductors adjacent the opposite or lower surface of the sheet 20.

The wire-mesh shield 26 provides a safeguard against signal transference between conductors 25a and other conductors in the system circuitry. In the present invention, it extends into the connectors 12 to provide such shielding along the full length of the conductors.

The cable 11 is prepared for receipt in a connector 12 by first stripping off one end of the insulating matrix sheet, only on the side of the wire-mesh grounding shield 26 opposite the conductors 25a, for a distance of approximately one-half inch, as illustrated in FIG. 4. This exposes a section 26a of wire-mesh grounding shield adjacent the end of the shield and permits this shield section to be peeled back to expose the matrix material above it.

With the shield section 26a peeled back, a secondary removal of material from the matrix sheet 20 is accomplished along a strip 28 extending substantially across the width of the sheet partially expose (approximately 50 percent conductor wires 25a a short distance from their ends.

The matrix sheet 20 and wires 25a, 25b are cut off immediately adjacent, but slightly outward, of the strip 28, leaving the free end of the wire-mesh shield section 26a extending outwardly of the cut-off sheet end and wires. Finally, a plurality of longitudinally elongated apertures 30 are formed through the matrix sheet 20 and shield 26 in spaced relationship, across the cable immediately adjacent the innermost end of the peeled back wire-mesh shield section 26a. The contacts 32 are then attached.

The contacts 32 are identical in construction and operation so only one is described in any detail. Referring to FIGS. 6-9 of the drawings, a contact 32 is seen to comprise a generally rectangular, male contact pin receiving sleeve 35 and a crimp section 36 joined by an intermediate section 37. The section 37 is in the form of a flat strip which is an extension of one wall of the sleeve 35. The crimp section 36 includes two pairs of U-shaped crimping teeth 39, extending perpendicular to the plane of the intermediate section 37 and terminating in relatively sharp ends 40.

To affix contacts 32 to the cable 11, the wire-mesh shield section 26a is peeled back and contacts positioned as illustrated in FIGS. 3 and 4 with crimping teeth 39 under the exposed strip 28 and bracketing corresponding conductors 25a and 26b. The sharpened ends 40 of the crimping teeth 39 are forced through the remaining thin layer of insulating material and crimped about corresponding conductors so as to affix the contacts 32 securely to the cable 11.

An elongated insulating interleaf card 45 is next interposed between the wire-mesh shield section 26a and the contacts 32 with their exposed crimp connections and conductors 25a adjacent it. However, the card 45, which is preferrably formed of a glass epoxy material, does not extend laterally between the wire-mesh shield section 26a and the contact 32 which is crimped to the conductor 25b. The significance of this relationship will be hereinafter explained.

The insulating card 45 has a plurality of rectangular notches 46 formed in its innermost edge and adapted to mate with corresponding apertures 30 formed through the matrix sheet 20. As a result, with the insulating card 45 disposed between the wire-mesh shield section 26a and the matrix sheet material adjacent it, the apertures 30 formed through this matrix sheet 30 (and the wire-mesh shield 26) are not covered by the card. Nevertheless, the outer edge 47 of the card terminates adjacent the innermost edge of the exposed shield section 26a.

With the insulating card 45 positioned as hereinbefore described, the connector housing 50 is assembled over the contacts 32, their connections with the conductors 25, the insulating card 45, and a portion of the remaining matrix sheet 20. According to the invention, the housing 50 is securely anchored to the sheet 20 and the shield 26.

The connector housing 50 includes a cable nest 51 and a cable cover 52, as best seen in FIGS. 6, 13 and 15--17. The nest 51 and cover 52, which are molded from an insulating phenolic material or the like, mate and lock together to form the housing 50.

The phenolic nest 51 is rectangular in configuration. Formed in its inner surface is a longitudinally extending well 60 extending substantially the length of the nest 51. The well 60 is bracketed on its longitudinally extending edges by a narrower cable support platform 61 adjacent its inner edge and a still narrower contact receiving wall segment 62 adjacent its outer edge.

A spaced series of contact access ports 69 are formed laterally through the wall segment 62. The ports 69 are elongated and have outwardly opening mouths 70 through which the pins 15 of the header 16, hereinbefore discussed, extend into the housing 50 for receipt within the contacts 32.

The housing cover 52 is substantially identical in general configuration to the nest 51. It is laterally divided by a stub wall 74 on its inner surface into a longitudinally extending contact cover segment 75 and a parallel cable cover segment 76.

The contact cover segment 75 has a series of laterally elongated contact access ports 77 molded therein and adapted to mate with corresponding ports 69 in the nest 51 to form contact retaining bores in the assembled housing 50. Like the ports 69, the cover segment ports 77 have flared mouths 78 through which male pins 15 are received.

The cable cover segment 76 has a series of anchor teeth 80 extending perpendicularly from it in spaced relationship along the length. The teeth 80 are adapted to pass through the apertures 30 in the matrix sheet 20 of the cable and anchor the cable in the housing. Energy directing ridges 81 on top of each tooth 80 are provided to actually engage the opposed surface of the nest platform 61. These ridges 81, and similar ridges 82 formed on the contact cover segment 75 melt under ultrasonic welding to bond the nest 51 and cover 52 together.

At opposite ends of the cover 52 and nest 51, in opposed relationship, are mating ears 85 and receiving slots 86. The ears 85 on the cover 52 fit snugly into the slots 86 when the cover 52 and nest 51 are pressed together to lock these components securely against relative lateral movement.

To assemble the housing over the prepared cable and contacts, as illustrated in FIG. 3, the cover 52 and nest 51 are positioned as illustrated in FIG. 4. Opposed surfaces of the contact receiving wall segment 62 and the cover segment 75, mating surfaces of the ears 85 and slots 86, adjacent ends of the cover 52 and nest 51, and the free ends of the anchoring teeth 80 are treated with a suitable adhesive.

The nest and cover are then pressed together with the teeth 80 passing through the apertures 30 in the cable and the notches 46 in the insulator strip 45. The insulator strip 45, with the woven wire shield portion 26a which it forces downwardly somewhat, as illustrated in FIG. 4, bends into the well 60 of the housing nest 51. Each contact sleeve 35 is received in a corresponding contact bore. The adhesive cements the nest 51 and cover 52 into a unitary housing 50. In the alternative, or in addition, bonding is effected by conventional ultrasonic welding techniques.

The housing 50 is securely anchored to the cable 11, through both the matrix 20 and the wire-mesh shield 26. The mesh shield 26 extends through the housing 50, over the contact connections to the conductors 25a and 25b, terminating slightly short of the free ends of the contacts 32. In the housing where the insulating matrix sheet 20 is separated from the wire-mesh shield 26, the contacts 32 and their connection to the conductors 25a are insulated from the shield 26 by the interleaf insulator card 45.

Note, however, that the contact connection to the conductor 25b is not shielded from the wire-mesh ground shield section 26a. The conductor 25b thus provides a ground wire and the contact 32 makes a ground connection with its mating male terminal pin.

Referring now to FIGS. 10--12, a shielded flat cable connector assembly embodying features of a second form of the present invention is illustrated generally at 110. The cable connector assembly 110 includes a section of shielded flat cable 111 terminating at its opposite ends in identical connectors 112 (only one shown).

The connector assembly 110 differs from the assembly 10 hereinbefore discussed only in that the shielded flat cable 111 is of the ribbon type manufactured by the Hughes Electronics Co., Inc., Los Angeles, Calif., hereinbefore referred to. The cable 111 includes a flexible matrix sheet 120 of insulating plastic material and, embedded in this sheet in longitudinally extending, parallel, spaced relationship, are a series of conductor ribbons 125.

The conductor ribbons 125 are spaced across a greater portion of the width of the plastic sheet 120. Sandwiched together with the sheet, and extending over a somewhat greater width than the width of the conductor series, is an aluminum foil grounding shield 126, laminated in a plastic cover. The plasticized shield 126 and the matrix 120 are stitched or otherwise bonded together along several longitudinal seams.

Unlike the connector assembly 10 of the first form of the invention, the cable 111 is prepared for receipt in a connector 112 solely by punching apertures 130 through it and crimping contacts 32 to the conductors 125. The matrix sheet 120 is separated from the plasticized shield 126 adjacent the end of the cable and contacts 32 crimped through the sheet 120 onto the individual conductors 125. Note here, however, that a contact 32a is actually crimped directly to the ground shield along one side of the cable to provide a ground connection for the mating contact pin 15.

The standard connector assembly housing 50 comprising the cable nest 51 and the cable cover 52 are then seated over the end of the cable 111 in virtually identical fashion to the first form of the invention. No interleaf insulator card is needed because the aluminum shield 126 is, itself, embedded in a plastic cover which is not stripped. The nest 51 and cover 52 are bonded together to lock and anchor the housing 50 on the cable.

Both forms of the connector assembly provide complete shielding of the current paths within and without the connectors. The shield is completely insulated from conductors and contacts along its entire length. Crimping of the contacts to the conductors is simple and reliable, as well as being inexpensive. The connection is simply and inexpensively protected against stresses to which cable and connector are subjected.

The invention has been described in terms of female pin receptacle contacts, set in a single row. However, it is readily adaptable to male contacts also. Furthermore, contact size and spacing may be varied within the purview of the invention.

While several embodiments described herein are at present considered to be preferred, it is understood that various modifications and improvements may be made therein.

Claims

What is desired to be claimed and secured by Letters Patent of the United States is:

1. An assembly for connecting a series of longitudinally extending, laterally spaced conductors embedded in the insulating matrix of a flat cable to contact elements of a circuit component wherein a ground shield of wire mesh is embedded in said matrix on one side of but normally insulated from said conductors, comprising:

a. a connector housing,

b. said housing having mouth means along one edge for receiving one end of said cable,

c. a segment of insulating matrix on said one side of said conductor being removed to expose said ground shield and at least a portion of said conductors,

d. said segment of insulating matrix being removed to a predetermined lesser depth along transverse outer edge strips so as not to expose said conductors and a predetermined greater depth along a transverse center strip to expose said portion of said conductors,

e. contact means connected to said conductors adjacent said one end of said cable and within said housing,

f. said contact means including crimp sections crimped through said remaining matrix in said center strip to grip corresponding conductors,

g. supplemental insulating means interposed between the conductors and contact connections and said ground shield in the area where said matrix segment has been removed, and

h. means in said housing for anchoring said housing to said matrix and said shield.

2. An assembly for connecting conductors enclosed in the insulating matrix of a flat cable to an electrical circuit component, wherein a ground shield extends parallel to said conductors substantially co-extensive with said matrix and said conductors, comprising:

a. a connector housing comprising a nest member and a cover member,

b. a contact crimped onto a free end of at least one of said conductors,

c. insulation means disposed between said contact and said ground shield,

d. a plurality of apertures formed through said matrix and said shield between said conductors,

e. said nest member and cover member sandwiching said contact and the end of said cable to which it is attached between them, and

f. a plurality of anchor teeth formed on one of said nest member and said cover member and extending through corresponding ones of said apertures,

g. the free ends of said anchor teeth being bonded to the other of said nest member and said cover member.

3. The connector assembly of claim 2 further characterized in that:

a. an ultrasonic bond is formed between the free ends of said anchor teeth and the other of said nest member and said cover member.

4. The connector assembly of claim 2 further characterized in that:

a. said ground shield comprises a wire mesh screen normally embedded in said matrix,

b. said matrix being stripped away from said wire mesh shield adjacent said one end of said cable to expose said wire mesh shield,

c. a portion of at least one of said conductors being exposed by stripping away insulation adjacent said wire mesh shield and said contact being crimped to said one conductor in the area of said stripped-away section, and

d. supplemental insulating means disposed between said wire mesh shield and said contact.

5. The connector assembly of claim 4 further characterized in that:

a. said supplemental insulating means comprises an elongated, generally rectangular card formed of insulating material,

b. said card extending transversely of said connector assembly between said wire mesh shield and a plurality of said conductors.

6. The connector assembly of claim 5 further characterized in that:

a. another one of said conductors has another contact crimped thereto,

b. said insulating card terminating short of said other conductor and contact whereby they are normally in electrical connection with said ground shield.

7. The connector assembly of claim 5 further characterized in that:

a. said insulating card has a plurality of notches formed along one longitudinally extending edge,

b. said notches adapted to mate with corresponding apertures formed through said matrix and said shield between said conductors.