Wrapped Insulation-piercing Connector

Abstract

This connector consists of a shell, an insulation-piercing type insert, a leaf spring therebetween, and a plastic film bonded to the shell. A spring force on the insert maintains long term contact of the piercing tangs with the conductors. A crimping tool is disclosed having a die with a main-slot wire guide for all splice types. Wires to be severed are led to a branching slot where, during splicing, the shell edge severs conductors therein. Useful for telephone gauge conductors, this connector system requires no insulation stripback or special handling skills.

Description

FIELD OF THE INVENTION

This invention relates to the joining of electrical conductors in the 19- to 26 -gauge range; and specifically concerns the making of solderless metal-to-metal insulated joints in such conductors.

Numerous expedients exist for the quick connection of one insulated conductor to another. Among such devices in widespread use are those described in U.S. Pat. Nos. 3,064,072; 3,436,820; and 3,012,219.

Notwithstanding the general acceptance of the foregoing items, there is yet a need for a splicing system which makes the bridging of conductors easier than at present; and the joining of large-pair-count cable a faster process.

Accordingly, the following are all objects of the present invention: To simplify conductor insertion in a solderless crimp-type electrical connector; To obtain better contact performance between the contacting element and the conductor to be joined; To permit bridging without the cutting of the through conductor; To achieve a connector design which permits automatic conductor trimming; To speed up the bridging of conductors in the field; and To expedite the joining of large-pair-count cable.

These objects and others are achieved by the insulation-piercing connector of the present invention. The connector consists of a shell, a piercing-type insert, a leaf spring therebetween, and a plastic film advantageously bonded to the shell. Connections are effected by a portable tool comprising a die with a main-slot wire guide for all splice types. In the splicing process, the edge of the shell severs conductors which are led up through a branching slot.

The spring force on the insert maintains long-term contact of the piercing tangs with the conductors. The insert advantageously is comprised of a spring temper phosphor bronze material which allows the formation of strong tangs. Convolutions at each end of the insert provide mechanical gripping of the conductors to prevent pullout.

The spring is compressed during the crimping, thus applying for the life of the connection a positive compressive force to the insert. A tendency exhibited in many previous designs of tangs to retreat from the conductor, because of a natural tendency for the insert to spring back and because of a long-term creep mechanism, is thus avoided.

The shell protects the insert from external disturbance, while transmitting forces between the insert and the spring. A fairly substantial force is generated by the spring in conjunction with an annealed brass shell, which constitutes a preferred inventive embodiment.

The design accommodates a large range of conductor combinations without requiring conductor insulation removal. Thus, connections may be made between two or three conductors ranging in gauge from 19 to 26.

The invention and its further objects, features, and advantages will be readily apprehended from a reading of the description to follow of an illustrative embodiment.

DESCRIPTION OF THE DRAWING

FIG. 1 is an exploded perspective view of a connector embodying the present invention;

FIG. 2 is the assembled connector of FIG. 1 prior to crimping;

FIG. 3 is a perspective view showing the connector of FIG. 1 fully crimped;

FIG. 4 is a frontal perspective view of an illustrative crimping die assembly used with the inventive connector;

FIG. 4a is a top view of the crimping die jaws of FIG. 4;

FIG. 4b is a frontal perspective view of the die jaws depicted in FIG. 4;

FIGS. 5 through 17 are various side sectional views of the connector of FIG. 2 showing connector bending and crimping sequences occuring in the crimping die;

FIG. 18 is a top perspective view of an alternate embodiment of the body and spring members of FIG. 1;

FIG. 19 is a top perspective view of an alternate embodiment of the spring and insert members of FIG. l; and

FIGS. 20 through 26 are schematic diagrams of various wire connections that may be made by the present invention.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

Connector Configuration

FIG. 1 shows the components of a connector 5 in exploded view prior to their being crimped. The shell, designated 10, is an elongated generally J-shaped member made of annealed brass, by a process of stamping. The walls 11, 12 of shell 10 each include perforations 13, 14 and 15, 16 respectively, symmetrically placed inwardly of the wall ends. On each of the two ends of the walls 11, 12 are inwardly extending tabs 17, 18 and 19, 20 respectively. The wall 11 is taller than wall 12, and includes one or more edge extensions such as extensions 21, 22, 23. To provide a firm cutting edge, the upper edge of wall 11 is hardened, as by inward compression, creating a groove 24 which extends from the wall end to edge extension 23; and a like groove 25 from the other end of wall 11 to the edge extension 21.

In the embodiment shown in FIG. 1, the spring member designated 30 advantageously comprises an elongated strip made of spring temper phosphor bronze and comprising relatively flat end portions 31, 32 and a central outwardly protruding bow portion 33. Spring 30 also includes along its sides, arms 34, 35, which locate in the perforations 13, 14 respectively, of shell 10; and arms 36, 37 which locate in the perforations 13, 14 respectively, of shell 10; and arms 36, 37 which locate in the perforations 15, 16 of shell 10.

The insert designated 40 is likewise made from spring temper phosphor bronze by the process of stamping. Viewed edge-on, insert 40 is J-shaped, and consists of a floor 41, a major wall 42, and opposite thereto minor wall 43. Insert 40 is substantially coextensive in length with shell 10. Wall 42 includes cutout portions 44, 45 at its ends, the cutouts 44, 45 engaging tabs 18, 17 respectively of wall 11 of shell 10, as seen in FIG. 2.

In the embodiment shown in FIG. 1, insert 40 consists of a field 46 inwardly protruding tangs centrally located in floor 41; and a field 47 of inwardly protruding tangs centrally located in the wall 42. The tangs of the tang fields 46, 47 are advantageously punched out, with spacings to ensure that any conductor in the range 19 to 26 gauge is contacted.

Outwardly of the tang field 46, on either side of floor 41, are formed a series of transverse ribs 48, 49, 50 at one end and 51, 52, 53 at the other end. Each two adjacent such ribs are provided with spaces between them. Wall 42 of insert 40 includes inwardly extending ribs 54, 55, 56 at one end and 57, 58, 59 at the other end. The ribs 54-59 likewise are transverse of wall 42 and advantageously commence at the edge 60 of wall 42, ending short of the bend line 61 between wall 42 and floor 41. The region between the end of each rib 54-59 and the bend line 61 is provided with raised nipples 62-67, respectively situated opposite the ends of ribs 54-59. The nipples 62-67 prevent wires from escaping from the tangs, and importantly also promote formation of a second bend line 61a to achieve parallelism between the floor 41 and the wall 42 after forming, as seen in FIG. 11.

As seen in FIG. 1, the floor ribs 48-50 and the wall ribs 54-56 are staggered in spacing so that when the insert 40 is folded during the effecting of a connection, these ribs shall interleave. Similarly, the ribs 51-53 are spaced with respect to the ribs 57-59 so that interleaving shall occur when the insert 40 is folded.

Advantageously, the edge of major wall 42 of insert 40 is provided with three cutouts 68, 69, 70; and the minor wall 43 of insert 40 is provided with cutouts 71, 72, 73. As seen in FIGS. 10 and 11 during the effecting of a connection and as the insert 40 is folded, the edge extensions 21, 22, 23 of the wall 11 of shell 10 are caused to engage the insert cutouts 68-70 and also the insert cutouts 71, 72, 73. This further locks the insert with respect to the shell.

A plastic film designated 80 is bonded to the shell 10 in the manner shown in FIG. 2, to provide electrical insulation for the metallic parts of the assembly. Plastic film 80 is generally J-shaped to conform to the shape of shell 10, but wider than shell 10, and its wall 82 is longer than the corresponding wall 12 of shell 10 as shown in FIG. 2. Plastic film 80 advantageously is corrugated longitudinally to provide both a degree of rigidity and extensibility in the transverse direction. Advantageously, the material from which film 80 is made is a polyester having good mechanical and electric properties as well as environmental stability. The bonding agent is, for example, a polyester adhesive having long-term adherence under severe environmental conditions.

An alternate embodiment of the shell 10 is shown in FIG. 18 in which the spring member is formed directly thereinto. In FIG. 18, certain numerals used in FIG. 1 denote parts which correspond identically to those shown for the shell 10 in FIG. 1. This alternate shell of FIG. 18, designated shell 10a, differs from that shown in FIG. 1 principally in that there is formed directly into the base 26 of shell 10a an inwardly extending bow 33a which corresponds in structure and function to the bow 33 of spring 30. The shell 10a combines the structure and function of the shell 10 with the spring 30 shown in FIG. 1.

FIG. 19 shows an alternate embodiment of the insert 40, designated insert 40a. Here again, certain numerals denote parts of insert 40a which are identical to those designated with like numerals for insert 40 in FIG. 1. The difference between the inserts 40 and 40a is that the central tang fields 46, 47 as well as the ribs 54-59 and 48-53 are replaced by a series of bowed or raised areas which have interleaving transverse serrated edges, these being designated serrated edges 90 through 97 located in wall 42, and 98 through 105 located in floor 41. The advantage of insert 40a is that a spring such as spring 30 is not necessary as resilience is inherent in this bow shape; and that furthermore, the transverse serrated edges 90 through 97 can be more precisely controlled as to shape and sharpness. The latter permits a more precise control of insulation penetration and contact with the underlying conductor.

Crimping Die

FIGS. 4, 4a, and 4b depict a crimping die designated 110 and consisting of a jaw 111 and a die 112. Jaw 111 is movable in the directions shown by arrow 113. The jaw 111 and die 112 advantageously are mounted on opposing arms of either a handtool or a bench tool (neither shown). Jaw 111 includes arms 114, 115 extending outwardly from, and then parallel to, the interior working surface of the jaw 111, defining slots 116, 117 in which the connector assembly 5 is mounted. The mounting of an assembled connector 5 is achieved by sliding the corrugated plastic film edges through the slots 116, 117 to achieve a light gripping. The body of jaw 111 and its working face against which the floor of connector 5 seats provides a firm bed with which to force the crimping action.

Die 112 consists of a body 120 mounted between a pair of side members 121, 122. Each side member includes a mouth defined between the top surfaces 123, 124 and front edges 125, 126, respectively. This mouth leads to a slot 127 in side 121 and a slot 128 in side 122. Springs 129, 130 are mounted across the slots 127, 128 and are bowed upwardly to made normal contact with the surface 123, 124, respectively. Conductor chambers 133, 134 are formed in the region behind the springs 129, 130 in which, as shown in FIG. 4, the conductors 131, 132 are grippingly accommodated.

The body 120 includes a nest 140, and a pair of cutting slots 141, 142. Above the nest 140 is a guide surface 143 with notched indentations 144, 145, 146 to accommodate the edge extensions 21, 22, 23 of shell 10 in a guiding manner.

Cutting slots 141 and 142 include bevels 147, 148 that serve as a cutting edge for a conductor such as 131 to be bridged, in a manner to be described.

Steps in Forming the Connection

The sectional view of FIG. 5 shows conductors 131, 132 suspended across the wire nest 140 and being approached by a connector assembly 5 which is being forced by the jaw 111. Conductor 131 has been led through the cutting slot 142 preparatory to its severance. The assembled connector 5 guides into position with its top wall 11 being guided by the top surface 149 of the body 120, and its bottom wall 12 being guided by the bottom guide surface 150 of body 120. It is seen in FIG. 5 that the leading lip 80a of plastic film 80 moves in advance of the wall 12. In FIG. 6, the wall 11 leading edge 11a moves against the conductor 131 insulation, driving it against the cutting edge of bevel 148. FIG. 7 shows the completion of the severance of conductor 131 in a shearing motion between the bevel 148 and the sharp leading edge 11a. The conductors 131, 132 are now positioned for envelopment by the connector 5.

FIGS. 8 through 11 portray the further sequence of crimping taken through a side section that illustrates the guided folding of edge extensions 21 through 23. In FIG. 8, edge extension 21 is channeled in notched indentation 146, best seen in FIG. 4b. The leading lip 80a of film 80 previously been folded back to the position shown in FIG. 8, by its riding along the curved surface of nest 140 as seen in FIG. 7. Thus, upon being bent in the notched indentation 146 as shown in FIG. 8, edge extension 21 (and its companions 22 and 23) capture the film leading lip 80a, folding it downwardly onto the interior surface of wall 12.

At about the point depicted in FIG. 8, the leading edge 11a encounters the guide surface 143 depicted in FIG. 4b. Further crimping forms the wall 11 into the bend depicted in FIG. 9 as the wall 11 rides over the extended edge 151 between the nest 140 and the guide face 143. The bend line 61a is seen in FIG. 8 to be materializing, and furthered in FIG. 9.

By virtue of the bending occasioned in wall 11 by the extended edge 151 and the top surface 149, the wall 11 assumes the bend depicted in FIG. 10. Here, edge extension 21 by virtue of previous bends is guided into cutout 68 of insert 40. The leading edge 11a approaches contact with the now completely overlapped leading lip 80a of plastic film 80. The conductors 131, 132 are about to be gripped by the entire series of ribs 48 through 53 and 54 through 59, which are shown in FIG. 1. The leading edge 12a of wall 12 has been forced into conformity with the curved surface of nest 140, and is in substantial overlapping relation with the edge 11a. Finally, as depicted in FIG. 11, the crimp is completed.

FIG. 12 is a section taken lengthwise of the wires which shows the ribs 48 through 59 gripping the conductors 131 and 132, the latter not shown.

FIGS. 13 through 17 depict the bending sequence taken through a section that includes the tang field 46, 47. The section is taken so as to include an edge extension 21 its notched indentation forming groove 146. FIG. 14 depicts the tang field 47 as clearing the conductors 131, 132 as the crimping proceeds. Finally, as seen in FIGS. 15, 16, and 17, the wires 131, 132 are enveloped and ultimately their insulation pierced by the tang fields 46, 47. The spring 30 is finally fully compressed as shown in FIG. 17 to provide lasting contact between the tang fields and the conductors as they are compressed between the spring and wall 11 of shell 10.

FIGS. 20 through 26 illustrate different types of connections that may be made with the described wrapped insulation piercing connector 5. In FIG. 20, a bridge conductor 160 is connected to a through conductor 161. In FIG. 21, two bridge conductors 162, 163 are connected to a through conductor 164. In FIG. 22, the through conductor 165 is connected to bridge conductors 166, 167 both of which exit from one side of the connector 5.

In FIG. 23 two joined conductors 168, 169 enter from a single side of the connector 5; and in FIG. 24, conductors 170 and 171 are connected within the connector 5. FIG. 25 demonstrates that three conductors 172, 173, 174 all leading into one side of the connector 5 may be therein connected. FIG. 26 shows the case of connecting two conductors 176, 177 coming into one side of the connector to a third conductor 178 leading from the other side.

Numerous other connection schemes are, of course, envisionable, the foregoing being merely illustrative instances.

Various modifications and changes may be made to the inventive embodiment described, and it is understood that all such changes are embraced in the spirit of the invention as defined in the scope of the claims to follow.

Claims

1. A connector for splicing telephone conductors, comprising; a J-shaped outer shell; a leaf spring loosely mounted on said shell at its base interior; and a metallic insert for receiving and engaging conductors, said insert disposed atop said spring and having a zone of insulation-piercing tangs, the closing of said shell effecting also a full closing of said insert around said conductors and also forming a roof against which said spring

2. A connector for splicing insulated electrical conductors, comprising: an elongated outer shell comprising a first wall, a shorter second wall, and a base portion therebetween; spring means disposed on said base portion between said walls and having a springy central region; compliant metal insert means for receiving conductors to be joined, said insert means disposed in said shell atop said spring means and having a major wall, a minor wall and a floor portion therebetween, the major wall and floor portion both having means located in their respective central regions for mechanically piercing said electrical insulation and for engaging the underlying conductor; means on either side of the respective said central regions for securely gripping the insulation of said conductor; means for effecting a joint between said shell first wall and the edge portions of said major wall and said minor wall upon a folding together of said shell and said insert edge portions during crimping; and

3. A connector in accordance with claim 2, further comprising means for mounting said spring means on said base comprising at least one extension on each edge of said spring and a like number of cavities in each said

4. A connector in accordance with claim 2, wherein said mechanical piercing means comprises opposing tang fields in the central regions of said major wall and said floor portions, and wherein said gripping means comprises plural protruding ribs spaced transversely on either side of each said tang field, said ribs being staggered to interleave with one another upon

5. A connector in accordance with claim 4, wherein the boundary between said major wall and said floor portion of said insert constitutes a first bend line and said insert further having a plurality of protruding nipples located beyond the interior end of each rib on said major wall, the region between said plural nipples and said major wall plural ribs constituting a zone for effecting a second bend line during folding of said insert means.

6. A connector in accordance with claim 5, further comprising means for mounting said insert on said base, comprising an upwardly extending tab at each end of said first wall and of said second wall of said shell, for

7. A connector in accordance with claim 6, wherein said plastic film overlaps said shell at the ends thereof, said film further having plural longitudinal corrugations, said film being affixed to said shell exterior, one film edge extending substantially beyond the edge of said shell second

8. A connector in accordance with claim 2, wherein said joint-effecting means comprises at least one edge extension of said shell first wall, and corresponding notches in the edges of said insert major and minor walls

9. A connector for splicing insulated electrical conductors, comprising: a J-shaped outer shell having a resilient bow-shaped base; a metallic insert for receiving and engaging conductors, said insert disposed within said shell and having insulation-piercing tangs, the closing of said shell effecting also a full closing of said insert around said conductors and also forming a roof against which said insert is compressed.