Module for telephone line conductor pair having single protector unit.

This invention relates to the field of electrical connectors and more particularly to connectors for connecting pairs of signal wires together.

In the telecommunications industry, telephone cable is introduced to individual telephone sites such as residences, mainly through use of a splice of the signal wires of the cable to respective house wires at a junction located outside or inside the house. The junction is housed within a protective enclosure which is mounted usually to an outside wall of the house. One example of an assembly of a splice terminal block and self-sealing enclosure therefor is disclosed in U.S. Patent Nos. 5,219,302 and 5,145,388. Therein, a terminal block has a single-piece barrel-shaped terminal with connecting sections for both wires to be spliced, and the terminal is of the insulation piercing or displacement type which eliminates the need for stripping the insulation from the signal wire conductors. A dielectric housing includes an integrally molded center post within a tubular terminal-receiving housing section, both co-extending from a common base section and defining an annular cavity, the housing section providing wire-receiving openings through side walls and into the cavity aligned with an aperture through the center post, enabling insertion of wire ends during splicing.

A barrel-shaped terminal and an associated lug-capped tubular actuator is then assembled to the housing, with the barrel terminal surrounding the center post within the cavity and having apertured insulation displacement contact sections which are initially aligned with the wire-receiving openings of the housing and center post, and the actuator also having profiled apertures therethrough extending partially around the circumference and also aligned with the wire-receiving openings of the housing, center post and terminal. The lug extends above the housing upon assembly to be accessible to tooling for rotation thereof to rotate the actuator and the terminal.

During splicing the wire ends of both wires are inserted into respective openings and through the apertured contact sections until abutting stop surfaces of the housing which then holds the wire ends at two spaced locations, both outside and within the terminal wall; the actuator is then rotated through an angular distance of about a quarter turn in turn rotating the terminal, and the constricted edges of a precisely profiled slot extending from each of the terminal's apertures penetrate the wire insulation of both wires simultaneously and engage the conductors therewithin, completing the splice.

The terminal blocks of U.S. Patent 5,219,302 are modular in nature, comprising a pair defined in the same housing member for mounting within an enclosure adapted for a plurality of such modules. The two-terminal block housing is mountable in a selected orientation such that the wire-receiving openings of each of the terminal blocks are oriented facing a cable exit of the enclosure, or other common point from where the pairs of conductors originate as discrete wires from two cables.

It is desired to provide the telephone line to a particular customer with overvoltage and overcurrent protection on the circuits which protect the circuits of the customer's equipment from energy surges, which may be induced by lightning for example. Several examples of protector units are disclosed in U. S. Patents Nos. 4,158,869; 4,161,762; and 4,133,019. Modules containing such protectors are disclosed in U.S. Patents Nos. 4,742,541; 4,159,500; 4,613,732 and 4,675,778. A protective plug for a distributor strip utilized in telecommunications systems is disclosed in U.S. Patent No. 5,154,639 to have a protector unit contained therein. The telecommunications industry has established standards for performance and certain dimensional and design requirements for such protectors; one example is Bellcore Technical Reference No. TR-TSY-000073, Issue 1, January, 1987, entitled "Customer Station Three-Element Gas Tube Protectors".

In U.S. Patent Application Serial No. 07/880,449 filed May 8, 1992, a single module is disclosed having two barrel-shaped terminals each with a pair of insulation displacement slots for termination by rotary actuation to respective conductors of two cables, for crossconnecting or splicing the tip and ring lines of a service line extending to a customer with a cable extending to the main distribution line. Each barrel terminal is in electrical engagement with a circuit element such as a wire length extending to a respective separate portion of the module for electrical connection to an active electrode of a respective protector unit within a respective housing section. The two protector units each include a ground electrode grounded to a common ground strap which includes a contact section exposed along the bottom of the module to be assuredly engaged with a ground strap along the floor of the enclosure upon mounting of the module therein, for grounding to a ground stud for external system grounding. The wire-receiving apertures of the two housing sections containing the terminals are preferably oriented to face a cable exit of the enclosure to facilitate receipt of the conductors for wire termination upon rotation actuation of the terminals by respective lug-capped actuators. An enclosure for protected terminal blocks or modules includes a ground strap extending from a ground stud to each terminal block mounting region, enabling the contact section of the module ground strap to engage its top surface upon mounting of the terminal block in position.

It is desired to provide a module for electrically connecting a pair of signal wires of a customer line with provision for integral means for protecting the circuits against voltage and current surges when the module is assembled within an appropriate enclosure, upon termination of a service wire to a terminal.

It is desired that such module permit in-line circuit protection simultaneously with splicing of the pair of wires of the service line.

It is additionally desired to protect both circuits interconnecting tip and ring lines of a service wire, with a single protector unit.

The present invention is a single module having two barrel-shaped terminals each with a pair of insulation displacement slots for termination by rotary actuation to respective conductors of two cables, for crossconnecting or splicing the tip and ring lines of a service line extending to a customer with a cable extending to the main distribution line. Each barrel terminal is in electrical engagement with a respective lead extending to a respective separate active electrode of a single protector unit disposed within a housing section, which may be a separate cover member securable to the main housing assembly. An advantage of both terminals being connected to leads of the same protector unit is that, if a voltage or current surge occurs on either the tip or ring circuit, the protector unit will short out both circuits to ground.

The protector unit includes a ground electrode grounded to a common ground strap which includes a contact section extending from the module to be assuredly engaged with a ground strap of the enclosure upon mounting of the module therein, for grounding to a ground stud for external system grounding. The wire-receiving apertures of the two housing sections containing the terminals are preferably oriented to face a cable exit of the enclosure to facilitate receipt of the conductors for wire termination upon rotation actuation of the terminals by respective lug-capped actuators.

In one aspect of the invention, the protector unit is first secured to a subassembly of the main housing member and terminals in respective sections thereof, with active electrode leads of the protector unit in electrical engagement with the terminals, and depending from a bottom surface of the main housing. The protector housing member may then be a separate housing member securable to the bottom surface of the main housing for a cavity thereof to receive the protector unit thereinto.

In another aspect of the invention, the protector unit affixed to the bottom surface of the main housing member includes a ground electrode lead which is positioned to be assuredly connected to a contact section of the ground strap affixed to the protector housing section upon urging the protector housing section against the bottom surface of the main housing member. The contact section has a lead-receiving slot into which the ground electrode lead is urged into an interference fit during assembly without requiring manipulation or tools. Thus the protector housing section can be free of any openings otherwise needed for tools to connect the ground electrode lead to the ground strap, and the cavity containing the protector unit can thus be easily environmentally sealed.

In yet another aspect of the invention, the protector housing section may be a separate member to be affixed to the bottom surface of the main housing member in an arrangement of interfitting flanges peripherally surrounding the assembly interface, and a sealing member may be incorporated into the interfitting flange arrangement to facilitate environmental sealing of the assembly interface.

It is a feature of the present invention to provide a single assembly adapted to receive and crossconnect ends of service and distribution tip and ring conductors and include integrally therewithin protection of the circuits thus defined against voltage and current surges.

It is a further feature to provide a single assembly having a single protector unit which protects both the tip and ring circuits.

It is also a feature to provide an environmentally sealed cavity surrounding the protector unit.

It is yet another feature to provide such a protected module having components which are easily assembled without special tools or procedures for either assembly or sealing.

A terminal block assembly for crossconnecting respective conductors of two-wire service cables having integral surge protection for the circuits thus defined, the assembly being of the type having a housing member for terminals disposed in terminal-receiving cavities of the terminal housing, a pair of conductor-receiving openings of the housing member for receipt of first conductors of first and second two-wire cables for termination to one of the terminals, and second conductors of the first and second two-wire cables for termination to the other of the terminals thus crossconnecting the service cables the assembly further includes a protector housing having disposed therein a protector unit including a ground electrode lead and a pair of active electrode leads, and further including a module ground strap secured thereto having a first contact section in electrical engagement with the ground electrode lead of the protector unit and a second contact section exposed for grounding engagement with an external ground circuit for system ground, and the electrode leads secured in electrical engagement with respective terminals upon complete assembly, whereupon the assembly provides voltage and current surge protection for the circuits of the service cables thus crossconnected with a single protector unit.

An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: <ul id="ul0001" list-style="none"><li>FIGURE 1 is an isometric view of the protected module of the present invention showing the assembly ready for receipt thereinto of ends of conductors of two dual conductor telephone cables for paired crossconnection;</li><li>FIGURE 2 is an exploded view of the components of the protected module of FIG. 1;</li><li>FIGURE 3 is a cross-sectional view of the protected module of FIG. 1 illustrating the protector unit and the connections of the leads thereof to the terminals; and</li><li>FIGURE 4 is a partial section view of the module showing the protector unit and the ground strap thereof disposed in the protector housing section.</li></ul>

Protected module 10 of the present invention includes a housing assembly 12 including a pair of housing sections 14 for respective barrel terminals 16, and a protector housing section 18 including a protector unit 20. Each housing section 14 has an annular cavity 22 therein about a center post 24, into which is inserted a barrel terminal 16 to surround the center post. Thereafter an actuator 26 is inserted into annular cavity 22 surrounding the terminal and having a lug-shaped cap 28 adapted to be rotated by an appropriate tool. Actuator 26 includes embossments engaging terminal 16 and enabling rotation of terminal 16 for wire termination. Ends of two wires 30,32 are inserted through respective apertures 34,36 of the housing section walls, through openings in the actuator, through openings 38,40 of the terminal and at least into apertures 42,44 of the center post all coaligned. Upon rotation of terminal 16 by actuator 26, profiled slots 46,48 extending from the openings of the terminal penetrate the wire insulation and electrically engage the conductors of both wires thereby interconnecting them. Both of wires 30 may be tip lines of a pair of dual conductor telephone cables, and both wires 32 can be ring lines of the cables.

Protector unit 20 disposed in housing section 18 includes a ground electrode lead 50 and a pair of active electrode leads 52,54 to extend into each annular cavity 22 of respective housing sections 14, to interconnect the terminal therein to protector 20. Each lead 52,54 includes an end section 56,58 extending within and along a groove 60,62 vertically along center post 24 to a free end 64. Free ends 64 of lead end portions 56,58 are insertable into respective apertures 66 into bottom surface 68 of module housing 12 which have tapered entrances facilitating insertion, and which are aligned with grooves 60,62. Upon full insertion along grooves 60,62, free ends are preferably bent toward the center of center post 24 along beveled surface portion 68 at the top of grooves 60,62; such bending secures the leads in place during assembly and facilitates initial bearing engagement with the bottom edge of a terminal 16 upon insertion of terminals 16 thereover and into annular cavities 22 without stubbing. The depth of each groove 60,62 is selected considering the diameter of end section 56,58 so that end section 56,58 protrudes laterally partially out of its groove 60,62 to engage the inside surface of terminal 16 in intimate contact therewith when terminal 16 is inserted into annular cavity 22 upon full assembly. Upon full terminal insertion, terminal 16 is held compressed against lead end portion 56,58 and is still rotatable in annular cavity 22 upon rotation of actuator 26.

A module ground strap 70 which extends outwardly of housing section 18 to a bifurcated contact section 72 at one end. Ground strap 70 extends toward housing 12 to a lead-receiving contact section 74 at the other end; beams 76 thereof define therebetween a slot 78 having a width just less than the diameter of ground electrode lead 50; and upon urging of lead 50 thereinto, an assured electrical connection between lead 50 and ground plate 70 is established by compression fit. Bifurcated contact section 72 is thus exposed to be easily electrically connected to a ground strap of an enclosure (not shown) within which protected module 10 is to be mounted, which is connected to system ground. Such an enclosure would have a ground post extending upwardly from the enclosure floor to be mechanically and electrically connected to bifurcated contact section 72. A pair of embossments on the enclosure floor optionally may be provided to located and orient module 10 by being received into corresponding recesses into the bottom surface of housing section 18.

Protector housing section 18 includes a large cavity 80 within which protector unit 20 is disposed. The protector housing section is assembled to housing member 12 at an assembly interface, with the cavity open to the proximate or bottom surface 68 of housing member 12, and preferably including a pair of interfitting flanges peripherally surrounding the assembly interface. Upper edge 82 of housing section 18 is peripherally recessed at 84 to interfit with internal recess 86 of lower edge 88 of module housing 12 as seen particularly in FIGS. 3 and 4. Internal recess 86 further includes a channel 90 defining a seat for a seal member 92 such as an O-ring, which is compressed therewithin upon securing of protector housing section 18 to module housing 12.

While protector housing section 18 may be affixed to housing member 12 in several possible ways, securing may be accomplished by utilizing at least a pair of cooperating latch arrangements. The embodiment shown includes four spaced projections 94 extending outwardly from upper edge 82 of protector housing section 18 defining downwardly facing latching surfaces 96, which are dimensioned to bear against the inside surface of internal recess 80 during final assembly (with the resilient nature of the plastic housing material permitting such cooperation), and are received latchingly into corresponding apertures 98 defined through the lower edge 88 from internal recess 86.

With the embodiment of protected module 10, the protector unit 20 may be affixed to the main housing with its active electrode leads 52,54 electrically connected to respective terminals 16 in annular cavities 22 to define a housing subassembly, with the protector unit 20 thus depending from bottom surface 68 at the assembly interface, to be received into cavity 80 of protector housing section 18 during final stages of assembly. It is preferable to provide a pair of slightly spaced apart lead-receiving nests 100 associated with ground electrode lead 50 of protector unit 20. Each of nests 100 contains a slot 102 and each nest 100 extends below bottom surface 68 of module housing 12 on either side of lead-receiving contact section 74 of ground strap 70, with slots 102 aligned with slot 78 thereof. During final assembly, with protector unit 20 disposed along and depending from bottom surface 68 of module housing 12, ground electrode lead 50 extends through slots 102 of spaced nests 100. As ground electrode lead 50 enters lead-receiving slot 78, nests 100 maintain lead 50 in position while bottoms 104 of slots 102 engage lead 50 and urge lead 50 downwardly into slot 78 in interference fit therethrough, assuring an electrical connection of the ground electrode of protector unit 20 with ground strap 70.

The ground strap 70 may be insert molded within the protector housing section 18, and thus embedded with only the bifurcated contact section 72 and the lead-receiving contact section 74 exposed. Optionally a separate ground strap member may be affixed to the molded housing section with its ground contact section extending outwardly through a slot in a wall of the housing, which then preferably would be sealed.

The arrangement of lead-receiving nests 100 and contact section 74 for connecting the ground electrode lead 50 to insert molded ground strap 70, allows the protector housing section 18 to be free of openings otherwise necessary for manually executed or tool-assisted electrical connection to be performed. The embodiment of protected module 10 thus includes a ground strap 70 adapted to become assuredly electrically connected to the ground electrode lead 50 of the protector unit 20 upon assembly of the protector housing section 18 to housing member 12 unassisted by manipulation, whereby the protector housing section may be free from having to provide any access to the ground electrode lead for connection to said ground strap, facilitating fabrication of an environmentally sealed assembly.

A protector 20 as shown is available from Shinko Electric Industries Company, Ltd., Nagano City, Japan under the trade identification Three-Element Ceramic Surge Arrestor having Part No. 3P-19AL350FSVS. Module ground strap 70 may be tin-plated copper alloy.