Insulation Pierce Type Connector

Abstract

A pierce type connector for a ribbon cable or the like having a body and a pair of contact tines extending from the body. The tines diverge laterally of each other away from the body. The tines have insulation pierce tips at the free ends and include conductor engaging corners diverging outwardly of the body. The terminals pierce the ribbon cable insulation and expose the conductors therein for contact with the conductor engaging corners.

Description

The invention relates to pierce type connector blocks for forming electrical connections with insulated conductors in ribbon cables or the like. The connector block includes a base for receiving and holding the ribbon cable and a cover holding a number of bifurcated pierce type contact terminals which, when the base and cover are assembled, extend into the insulation on either side of each conductor to form electrical connections with the conductors. Connector blocks of this type are disclosed in U.S. Pat. Nos. 3,012,219, 3,434,093, 3,444,506 and 3,680,032.

In the improved contact terminals of the present invention the tines of each terminal are laterally offset or bent to opposite sides of the base from which they extend. In one embodiment the tines are twisted to opposite sides of the base and in another embodiment the tines are bent at the base to provide the offset.

When inserted into a ribbon cable or insulating body surrounding a conductor, pierce points at the end of the tines puncture the cable or insulation and stress the insulation between the tines and diagonally across teh conductor so that further insertion into the insulation results in the formation of a slit in the insulation extending between the tines and across an exposed portion of the conductor. The offset tines spread the slit open. Continued insertion brings contact corners on the tines into engagement with the exposed conductor to form a high pressure and wiped electrical connection therebetween. The tines bite into the conductor sufficiently to assure a reliable connection. Because the connection is formed between the tines and the exposed conductor within the slit in the insulation, the insulation does not become trapped between the tines and the conductor and impair the electrical connection.

The connectors disclosed in U.S. Pat. Nos. 3,012,219, 3,434,093, 3,444,506 and 3,680,032 utilize pierce type bifurcated contacts for forming an electrical connection with an insulated conductor. In these patents the tines are not offset along the length of the conductor with the result that upon insertion of the contacts over the conductor, the insulation surrounding the conductor may become drawn between the tines and the conductor and thereby impair the connection.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings, of which there are two sheets.

IN THE DRAWINGS:

FIG. 1 is a side view of a terminal used in the pierce type connector;

FIG. 2 is a view of a connector according to the invention prior to closing;

FIG. 3 is a front view of the connector of Figure a after closing;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3 and illustrating the contact between one of the terminals in the block and a conductor in the cable;

FIG. 5 is a sectional view illustrating the relationship between the terminal and the cable during closing of the block;

FIGS. 6 through 9 are views similar to that of FIG. 5 illustrating the terminal piercing the cable and establishing electrical connector with a conductor therein;

FIG. 10 is a side view of a pierce type terminal of a different embodiment of the invention;

FIG. 11 is a side view of the terminal of FIG. 10;

FIG. 12 is a sectional view taken through a pierce type connector block utilizing terminals as in FIG. 10 and showing the terminal in engagement with conductors in the ribbon cable;

FIG. 13 is a sectional view taken along line 13--13 of FIG. 12 illustrating the position of the ribbon cable in the connector block prior to closing the block; and

FIGS. 14 through 16 are sectional views similar to FIG. 4 illustrating movement of the terminal of FIG. 10 through the thickness of a cable and into electrical connection with a conductor therein.

Connector block 10 illustrated in FIG. 2 includes a base 12 formed of insulating material and having a cable receiving recess 14 therein and cover 16 which is provided with a number of terminal receiving holes 18 extending through the thickness thereof. Pins 20 project from the cover 16 and upon closing of the connector extend into guide holes 22 in the base. A number of holes 24 are formed in the bottom surface of cable recess 14 with each hole 24 beneath a hole 18 in the cover. Tape cable 26 includes an elongate insulating body with a number of metal conductors 28 confined therein. The conductors extend along the length of the cable. The cable fits snugly within recess 14 with each conductor 28 located above one of the holes 24. As illustrated in FIG. 2, the holes 18 and 24 are staggered with respect to the width of the cover and base to provide separation between the holes for adjacent conductors in the cable.

Terminal 30 illustrated in FIG. 1 is preferably stamp formed from relatively thin sheet metal stock and includes a terminal tail portion 32 adapted to mate with a female disconnect contact or to form a support for a wire wrap type connection. Bifurcated contact 34 is located on one end of the tail and includes a base 36 joining tail 32 and a pair of spaced tines 38 extending from the base away from the tail. Slot 40 separates the tines. Pierce points 42 are located on the outside edges of the tines. The contact portion 34 has two sides, with the slot 40 extending between the sides. FIGS. 1 and 5 through 9 show one side of the portion 34.

As illustrated best in FIG. 5, the ends of the tines 22 are twisted relative to the flat base 36 so that the respective edges 44 facing slot 40 are bent away from each other and to either side of the base. Prior to twisting the edges 44 defining the slot 40 are parallel and the slot 40 has a uniform width. After twisting the edges are separated adjacent the ends of the tines and the width of the slot defined by the minimum separation between the tines, decreases from the open end of the slot to the closed end at base 36. The terminal 30 is preferably punch formed with square corners on the tines.

A terminal 30 is seated in each hole 18 in cover 16 with the tines projecting outwardly of the cover. As indicated in FIG. 5 the tail portion 32 is seated snugly within the hole 18 and the expanded width base 36 is fitted within enlarged seat 46.

The cable 26 is positioned within recess 14 of base 12 and the connector 10 is then closed to establish electrical connection between each terminal 30 and a conductor 28 in the ribbon cable 26. Each conductor 28 is positioned above a hole 24. As the connector closes, pilot pins 20 fit within holes 22. This occurs prior to engagement between the tines 38 and cable 26. After the pins are positioned in the holes to assure that each terminal 30 is positioned above a conductor 28 and hole 24 in the base, the cover is forced down upon the base so that the terminal contact portions 34 pierce the cable and form electrical connections with the conductors 28. FIGS. 4 through 9 illustrate the relationship between the terminals and conductors during closing of the block 10.

FIG. 5 shows the position of a terminal above the tape cable immediately prior to engagement therewith. The conductor 28 in the tape cable extends across hole 24 in base 12. Tines 38 of the terminal 30 located above the hole 24 are positioned above conductor 28 with insulation pierce tips 42 spaced to either side of the conductor. The relatively wide spacing between the pierce tips assures that if a conductor 28 offset somewhat to one side of the center line of the terminal 30 will be picked up and guided into the slot 40. This is important because in the manufacture of tape cables there is a relatively large tolerence for the position of the individual conductors.

Further closing of the connector block forces the pierce tips or points 42 through the insulation of the ribbon cable 26 as illustrated in FIG. 6. The sharp points puncture the cable. Note that the wire is confined between lead in edges 48 on the ends of the tines. With continued closing of the block the tines are forced through the tape cable insulation. The continued movement through the tape cable stresses the insulation between the two punctures in the cable and opens a diagonal slit 50 extending across conductors 28 and between the two tines. The twisted or spread tines open the slit to expose the conductor 28 as shown in FIG. 7. Outer tine sides 52 and outer tine edges 54 are maintained in engagement with the insulation of the tape cable and hold the slit open. Inner tine sides 56 and lead in edges 48 and slot edges 44 are within the slit 50 and are free of the insulation.

Movement of the tines 38 down over the conductor 28 after formation of the slit 50 forces the conductor into slot 40. As the conductor moves into the slot tine corners 58 engage the sides of the conductor. Because the tines are bent the corners 58 diverge away from the bottom of slot 40 at base 36. Thus, as the conductor is forced into the slot the sharp corners bite into the conductor and move closer to each other along the axis of the conductor. The edges 44 and inner tine sides 56 adjacent the corners 58 are also brought into intimate engagement with the conductor. Engagement between the conductor and the tines upon movement of the conductor into the slot 40 is illustrated in FIGS. 8 and 9. FIG. 4 illustrates the position between the conductor and tines when the block 10 is fully closed. The corners 58 define the minimum separation or width of the slot.

Tension slit 50 is formed in the insulation of the ribbon cable prior to engagement between corners 58 and the conductor, thus assuring that the insulation is moved from the contact area. In this manner the reliability of the connection is increased over that of conventional pierce type connector blocks of the type disclosed in the United States patents previously mentioned.

The connection between the tines and the conductor is also improved because the tine corners 58 and adjacent contact areas are moved laterally along the axis of the conductor a slight distance thereby providing a desired wiping action which breaks up any oxide coatings on the mating apparatus. The corners 58 bite into the conductor 28 a slight distance, further assuring that there is a desired low resistance connection.

As the tines 38 are forced down over the conductors 28, the engagement between the corners 58 and conductors exerts a bending moment on the conductors and may impart a shallow S-shaped bend to them. When block 10 is assembled, the terminal tines 38 extend freely into holes 24 in base 12. As illustrated in FIG. 5 the holes 24 are considerably larger than the tines.

FIGS. 10 through 16 illustrate a modified connector block 70 according to the invention. Block 70 includes a base 72 having an elongate tape cable receiving slot 74 formed therein beneath the top surface 76. Cover 78 is provided with a number of terminal receiving cavities 80 spaced in two rows thereon. A lead opening 82 extends into each cavity 80 from the top of the cover. A terminal 84 illustrated in FIGS. 10 and 11, is seated in each cavity 80.

Terminals 84 each include a U-shaped body 86 with a pair of cantilever contact arms 88 extending to one side of the body. A bifurcated contact 90 extends from one of the legs of body 86 and includes a base 92 extending laterally from the contact arm halfway toward the other arm with a pair of tines 94 spaced apart by slot 96. As with terminal 30 the terminal 84 is preferably stamp formed from thin sheet metal stock with the edges of the contact 90 extending perpendicularly to the side surfaces. The contact 90 is also two-sided with slot 96 extending between the sides. FIG. 11 illustrates one side of the contact.

Flat tines 94 are bent to either side of the end of base 92 as illustrated best in the side view of the contact 90 illustrated in FIG. 12. Tines 94 include pierce points 98, lead in edges 100, interior edges 102 facing slot 96, outer tine edges 104, outer tine sides 106 and inner tine sides 108.

Terminals 84 are inserted in cavities 80 in cover 78 through openings 110 so that the contact arms 88 are in position to form electrical connection with lead 112 inserted through openings 82 into cavities 80. Bifurcated contact portions 90 extend outwardly of cavities 80 through openings 110. Barbs 114 may be formed on the outer surfaces of U-shaped bodies 86 to engage the side walls of cavity 80 and confine terminals 84 therein.

A number of circular openings 116 are formed through the top of base 72 and communicate with slot 74. As with openings 24 in base 12 of connector 10, openings 116 of base 72 are each located above a conductor 118 in the end of a ribbon cable 120 positioned in slot 74. The cable fits snugly within the slot so as to assure that the conductors are located accurately with respect to the openings 116. Openings 122 are formed in the bottom of slot 74 immediately beneath each opening 116. These openings are somewhat smaller than openings 116 and receive contact tines 94 of terminals 84 upon closing of the block, as illustrated in FIG. 12. These openings are considerably larger than the tines.

FIGS. 14, 15 and 16 illustrate engagement between the contact tines 94 and the ribbon cable 120 during closing of the conductor 70. The connector is provided with appropriate locating means, such as the pins 20 and alignment holes 22 of connector 10, to assure that the base 72 and cover 78 are properly oriented during closing. In this position each terminal 90 is located above an opening 116 in the base with a conductor 118 positioned between tines 94 and opening 122.

Upon closing of the block 70 tine pierce points 106 pierce the ribbon cable insulation to either side of conductor 118 as illustrated in FIG. 15. Further movement of the tines into the cable stresses the insulation between the tines and forms a slit 124 extending between the tines. A bared portion of conductor 118 extends through the slit. The divergent tines spread the slit. Tine outer edges 104 and outer sides 106 are in engagement with the ribbon cable insulation while slot edges 102 and inner sides 108 are within the slit and free of the insulation. The lead contact corners 126 defined by the intersection of sides 108 and inner edges 102 are located within the slit.

Since the pierce points 106 straddle the conductor 118, further movement of the tines into the ribbon cable forces the conductor into slot 96 and into engagement with the corners 126. Because the tines are bent the corners diverge from the bottom of the slot so that as the connector 70 is closed the corners bite more deeply into the conductor 118 and move toward each other along the longitudinal length of the conductor to form a reliable electrical connection therewith. The corners 126 define the minimum separation or width of the slot.

The nature of the electrical connection between conductor 118 and the bifurcated contact 90 of terminal 84 is essentially identical to the connection formed between the contact portion 34 of terminal 30 and conductor 28. In each case the insulation is spread from the contact area prior to engagement between the tines and the conductor and there is a desired wiping and limited coating engagement therebetween. In both cases the conductor may be bent through a shallow S curve as illustrated in FIGS. 4 and 18.

Upon closing of block 70 as illustrated in FIG. 12, each terminal 84 engages an individual conductor 118 in the cable 20. The cover 78 and base 72 may be held together by suitable conventional latch means. As illustrated in FIG. 12, the ends of the tines 94 project freely into the holes 122 beneath slot 74.

While both connector blocks 10 and 70 have been disclosed in connection with forming electrical contacts with ribbon cables having solid conductors therein, the bifurcated contacts 34 and 90 may also be used for forming electrical connections with stranded or other conductors having sufficient internal strength to withstand the contact pressures during movement of the tines over the conductor.

The width of the slit in the insulation extending between the ends of the tines in terminals 34 and 84 is increased because of the offset of the tines with respect to the axis of the conductor. While the resistance of the insulation to being spread bows the plastic inwardly at the edges of the slit between the tines as illustrated in FIGS. 4 and 15, the offset tines maintain the width of the slit sufficiently to assure that the insulation is removed from the contact areas. Because the pierce points engage the insulation at locations longitudinally offset from the contact areas between the tines and the conductor, it is not possible for insulation to be dragged along the lead in surfaces extending from the points to the slots and be caught in the contact area.

While I have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

Claims

What I claim as my invention is:

1. A pierce-type connector block for forming electrical connections with elongate conductors confined within a ribbon cable or the like, comprising a support for a ribbon cable, recess means in said support located beneath conductors in the cable, a cover, and two-sided pierce type terminals mounted in said cover for piercing the cable, engaging the conductors therein and extending into said recess means, each terminal including a base, a slot extending between the sides of the terminal to define a pair of spaced contact tines extending from the base outwardly of the cover for engagement with a conductor in the cable and into said recess means, each tine including an outer side on one side of the terminal, an inner side on the other side of the terminal, an edge joining said sides at the slot, and a contact corner at the junction of the edge and the inner side, said corners extending along opposite terminal sides away from the bottom of the slot and defining the minimum width of the slot, such minimum width increasing away from the bottom of the slot so that the corners diverge outwardly from the bottom of the slot, and insulation pierce means on the ends of the tines for piercing the cable and forming a slit in the insulation extending across the conductor as the terminal is pushed into the cable, whereby upon positioning of a ribbon cable between said cover and support the tines of each terminal pierce the cable insulation to either side of a conductor and extend into said recess means and said corners wipe along opposite sides of the conductor to form an electrical connection therewith.

2. A connector block as in claim 1 wherein said tines are generally flat and extend away from the base in diverging directions.

3. A pierce-type connector block for forming electrical connections with elongate conductors confined within a ribbon cable, recess means in said support located beneath conductors in the cable, a cover, and pierce-type terminals mounted in said cover for piercing the cable engaging the conductors therein and extending into said recess means, each terminal including a base, a pair of spaced contact tines extending from the base outwardly of the cover for engagement with a conductor in the cable and into a said recess means, said tines diverging away from the terminal base to define a diverging slot therebetween, said tines being twisted in opposite directions along the slot, insulation pierce points on the ends of the tines away from the slot for forming a slit in the insulation extending across the conductor as the terminal is pushed into the cable, lead-in surfaces extending from pierce points to the slot, contact surfaces on opposing edges of the slot for forming an electrical connection with one conductor in the cable and slit spreading means for opening the slit and exposing a portion of the conductor to the contact surfaces free of the insulation.

4. A pierce-type connector block for forming electrical connections with elongate conductors confined within a ribbon cable or the like comprising a support for a ribbon cable, a ribbon cable on the support, recesses in said support located beneath conductors in the cable, a cover on the cable, and two-sided pierce-type terminals mounted in said cover engaging the conductors in the cable and extending into said recesses, each terminal including a base, a pair of spaced contact tines extending from the base outwardly of the cover and into a recess, said tines diverging outwardly of the terminal base in opposite directions along a conductor to define a diverging slot therebetween, insulation pierce points on the ends of the tines away from the slot and spaced along the conductor and on opposite sides thereof for forming a slit in the insulation extending across the conductor as the terminal is pushed into the cable, contact surfaces on diagonally opposing corners of the slot forming an electrical connection with the conductor in the cable, said corners diverging outwardly from the bottom of the slot and defining the minimum width of the slot, and slit spreading means for opening the slit and exposing the conductor to the contact surfaces free of insulation.

5. A connector block as in claim 4 wherein said slit spreading means comprises the outer side surfaces of said tines located on opposite sides of the terminal.

6. A pierce-type connector block for forming electrical connections with elongate conductors confined within a ribbon cable or the like comprising a support for a ribbon cable, a ribbon cable on the support, recess means in said support located beneath conductors in the cable, a cover on the cable, and pierce-type terminals mounted in said cover engaging the conductors in the cable and extending into said recess means, each terminal including a base, a pair of spaced contact tines extending from the base outwardly of the cover and into a recess, said tines diverging outwardly of the terminal base in opposite directions along a conductor to define a diverging slot therebetween, insulation pierce points on the ends of the tines away from the slot and spaced along the conductor and on opposite sides thereof for forming a slit in the insulation extending across the conductor as the terminal is pushed into the cable, contact surfaces on opposing edges of the slot forming an electrical connection with the conductor in the cable and slit spreading means for opening the slit and exposing the conductor to the contact surfaces free of insulation, the conductors including curved shallow S-shapes adjacent the terminals with the tines engaging the conductors at the centers of the curved shapes.

7. A connector block as in claim 6 wherein the tines are flat.

8. A connector block as in claim 6 wherein the tines are twisted along the slot.

9. A terminal as in claim 16 wherein said tines are generally flat and extend away from the base in diverging directions.

10. A terminal for piercing an insulating body and forming an electrical connection with an elongate conductor within the body comprising a base, contact means joining the base, and a pair of tines extending from the base and defining a slot therebetween, pierce points on the free ends of the tines away from the slot, contact surfaces on the tines adjacent the slot for engaging the conductor, said surfaces diverging from each other away from the bottom of the slot, and spreading surfaces for spreading open a slit formed in the insulation extending across the conductor whereby upon insertion of the terminal into the insulating body with the tines to either side of a conductor the pierce points form a slit in the insulation extending across the conductor and, with further movement of the terminal, the spreading surfaces open the slit and contact surfaces engage the conductor free of the insulating body, said tines being twisted in opposite directions along the slot.

11. The method of forming an electrical connection between an insulating conductor and a pierce-type terminal having a pair of tines comprising the steps of:

a. Positioning the terminal to one side of an elongate insulated conductor with the free ends of the tines to either side of the conductor and spaced apart in a direction along the axis of the conductor,

b. Moving the terminal toward the conductor and forcing the ends of the tines in the insulation to form a slit in the insulation extending between the ends of the tines and diagonally across the conductor,

c. Continuing to move the terminal toward the conductor while at the same time spreading open the slit so that the portion of the conductor between the tines is exposed free of the insulation, and then

d. Forming an electrical connection between the tines and the exposed portion of the conductor free of the insulation.

12. The method of forming an electrical connection between an insulating conductor and a pierce-type terminal having a pair of tines comprising the steps of:

a. Positioning the terminal to one side of the insulated conductor with the free ends of the tines to either side of the conductor,

b. Moving the terminal toward the conductor and forcing the ends of the tines in the insulation to form a slit in the insulation extending between the ends of the tines and across the conductor,

c. Continuing to move the terminal toward the conductor while at the same time spreading open the slit so that the portion of the conductor between the tines is exposed free of the insulation,

d. Forming an electrical connection between the tines and the exposed portion of the conductor, and

e. Wiping the tines in a longitudinal direction along opposite sides of the conductor.

13. A connector block as in claim 1 wherein said tines are twisted in opposite directions along the slot.

14. A connector block as in claim 1 wherein said tines are generally flat and the outer tine surfaces are spaced further away from each other than the inner tine surfaces.

15. A connector block as in claim 1 wherein said recess means comprises an opening in the support beneath each terminal having side walls free of said tines so that the tines extend into the opening without engaging said side walls.

16. A connector block as in claim 15 wherein said tines are generally rectangular in cross section and said recess means comprises an opening beneath each terminal having a pair of generally rectangular sections overlaping at adjacent corners.

17. A two-sided terminal for piercing an insulating body and forming an electrical connection with an elongate conductor confined within the body, said two-sided terminal comprising a base, a slot extending between the sides of the terminal to define a pair of spaced contact tines extending from the base for engagement with the conductor, each tine including two sides, an edge joining said sides at the slot, and a contact corner at the junction of the edge and one side, the contact corners of said tines being located on opposite terminal sides and defining the minimum slot width and diverging apart from each other outwardly from the bottom of the slot, and insulation pierce means at the ends of the tines.

18. A two-sided terminal for piercing an insulating body and forming an electrical connection with an elongate conductor confined within the body, said two-sided terminal comprising a base, a slot extending between the sides of the terminal to define a pair of spaced contact tines extending from the base for engagement with the conductor, a contact corner extending along the tines at each side of the slot and defining the minimum slot width, said corners diverging apart from each other outwardly from the bottom of the slot, one side of each corner being located on opposite terminal sides, and insulation pierce means at the ends of the tines.