Abstract:
Terminal elements for interconnecting insulated wires. Twin-contact terminal elements are formed of leaf-shaped sides of resilient contact material, each side having a slot for solderless, screwless and stripless clamping contact with an individual wire. The terminal elements are V-shaped, a plurality of which can be mounted in an insulative terminal strip so that each two adjacent terminal elements are disposed with their sides in parallel confronting relationship.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 235,432, filed Feb. 17, 1981, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to devices for connecting insulated wires to terminal elements and more particularly to solderless, screwless and stripless terminals for interconnecting two or more wires. 
     DISCUSSION OF THE PRIOR ART 
     Solderless, screwless and stripless clamping connectors with twin contact members for the connection of two adjacent telecommunications cable conductors or jumper wires are known in various embodiments. As an example, German Pat. No. 2 142 850 shows an electrical clamping device for connecting one or more insulated wires to a terminal element with at least two slots. Another example is German Pat. No. 1 765 584 which shows a clamping connection between one or two insulated wires and a terminal element with two slots, each consisting of two contact arms resilient relative to one another and suited to penetrate the wire insulation. These clamping connectors have disadvantages in that when a plurality of them are mounted in terminal strips they require modifications causing additional manufacturing expenses. They also use significant terminal strip space in the case of side-by-side arrangement. 
     A V-shaped terminal having two slots, one slot thereof serving to retain and the other one serving to contact the conductor, is shown in U.S. Pat. No. 3,824,527. Each of the slots of that terminal is constructed differently. Additionally, much space is required when a plurality of those terminals are mounted in terminal strips. Further, one terminal having two slots accommodates only a single wire. 
     In all of the above examples, the wire enters the slot substantially perpendicular with the plane of the contact. When several are mounted together side-by-side in a terminal strip, considerable space is necessary. 
     Another example is the device shown in U.S. Pat. No. 4,283,103 where slotted terminals are arranged at a 45° angle with respect to the axis of the wire to be connected. In that terminal, each side of the slot is free to move unless positively supported within the terminal strip. Each terminal connects with a single wire. 
     SUMMARY OF THE INVENTION 
     Broadly speaking, this invention provides terminal elements mounted in a terminal strip in such a way as to reduce costs and space requirements, while interconnecting two insulated wires in parallel fashion. 
     Each terminal element has two planar arms or sides interconnected in a V-shaped configuration, each side receiving an individual wire in a slot. A plurality of these terminal elements are mounted side-by-side in an insulative terminal strip with their sides arranged in a parallel confronting manner to conserve longitudinal space in the terminal strip. The inner edges of each side of the V-shaped terminal element are interconnected and therefore self supporting and rigid. The outer edges are supported by the terminal strip. 
     Thus a relatively inexpensive but rigid terminal element is formed to make positive electrical and mechanical contact with two insulated wires in parallel relationship without adverse stresses on the terminal element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The objects, advantages and features of this invention will be more apparent from the following detailed description when read with reference to the accompanying drawing in which: 
     FIG. 1 is a partially cut away plan view of a terminal strip showing the relative positions of the V-shaped terminal elements of the invention; 
     FIG. 1a is a cross-sectional view of the device of FIG. 1 taken along line 1a--1a and showing the terminal elements of FIGS. 3 and 4; 
     FIG. 2 shows an embodiment of a terminal element as a simple V-shaped twin contact member; 
     FIG. 3 is a preferred embodiment of the terminal element as shown in FIG. 1a; 
     FIG. 4 is a terminal element corresponding to FIG. 3 of reversed V-shape; 
     FIG. 5 shows an alternative embodiment dual terminal element; and 
     FIG. 6 shows a terminal element corresponding to FIG. 5 with a central tap contact. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference now to the drawing, terminal elements 2 are shown as V-shaped twin contact members. Each individual arm or side 2a, 2b of the terminal element 2 forms a solderless, screwless and stripless contact member. These are of the well-known LSA-PLUS type, where an insulated wire 15, 16 is inserted in slots 21, 22 in either arm at a 45° angle with respect to the plane of the arm. An enlarged tapered opening is provided to facilitate proper location and entry of the wire into the slot. The inside edges of each arm 2a&#34;, 2b&#34; are interconnected at the apex of the V, and the outer edges 2a&#39;, 2b&#34; are supported in grooves 8, 9, 10, 11 in the terminal strip. Upon entry of the wire into the slot an opposite direction torquing will occur at the edges of the slot and the sharp edges will penetrate the wire insulation and contact the central conductor. Enlarged relief openings 25, 26 are formed below the slots to enhance the torquing effect when a wire is inserted. 
     As shown in FIG. 1, the terminal elements are mounted longitudinally in terminal strip 1. Advantageously, the angular surfaces 2c of two adjacent terminal elements 2 are disposed in parallel opposite relationship. Two mating terminal elements of FIGS. 3 and 4 are shown in FIGS. 1 and 1a mounted in the terminal strip. Note that the two terminal elements alternate as they are inserted into the terminal strip so that each has one side parallel with a side of the next adjacent element. This facilitates efficient use of space with respect to the length of the terminal strip. 
     The terminal elements shown in FIGS. 1a, 3, 4, 5 and 6 have extensions 3, 3a below the contact portion. In terminal elements 2 of FIGS. 3 and 4 the extensions 3, 3a are disconnectable normally-closed contacts, which, as is known, may be disconnected by an insulative disconnecting plug (not shown), which may be inserted through the opening 4 of the terminal strip 1 so as to disconnect contact bights 5 of the extensions. 
     Ribs 6 (FIG. 1), in addition to grooves 8-11, provide support for the outer edges of terminal element sides 2a&#39;, 2b&#39; when and after a wire is inserted into the slot, as well as being a guide for the wire itself. Further, each pocket in the terminal strip for receiving a terminal element is substantially rectangular and has a slotted structure which confines and supports the outer edges of the elements. During the contacting operation, the two outer contact arms 2a&#39;, 2b&#39; of a terminal element are supported by the insulating body of the terminal strip 1 with the two inner arms 2a&#34;, 2b&#34; supporting one another as stated above. 
     FIG. 5 shows an alternative terminal element having a pair of twin contact members or sides 2a, 2b with an extension 3 forming a cross connection between them. With this embodiment a total of four conductors may be connected to the same element, two on each side of the terminal strip. 
     FIG. 6 also shows another terminal element for four conductors, corresponding to FIG. 5, with a center tap contact member 7. This center contact would typically be used to connect to a surge arrester which, in a separate stack arrangement somewhat similar in configuration to the terminal strip, mounts on top of strip 1 and has contact members extending into openings 4. 
     The structure shown and described provides a relatively inexpensive terminal element which, with its internal longitudinal support (the V-shape) and external support by the terminal strip grooves, is quite rigid when subjected to the forces associated with inserting and retaining a wire. The longitudinal interconnection of the arms at the apex of the V provides substantial longitudinal rigidity for the terminal. Even though slots 21, 22 together with relief openings 25, 26 are more than half the length of arms 2a, 2b, support for outer arms 2a&#39;, 2b&#39; provided by the terminal strip grooves is adequate to prevent relative movement of the outer arms with respect to the inner arms upon insertion of a wire 15, 16. 
     When a wire is inserted into a slot 21, there is a relative torque on the facing edges of the slot. Also a net torque will result on the terminal with only one wire connected to it. However, with the V-shaped configuration and two parallel wires as shown in FIG. 1, opposite and equal torques are applied to terminal element 2, resulting in a net zero torque on the element. It is also important to observe that each of the two slots are independent and the insertion of a wire into one has no effect on the other arm of the terminal element. 
     Another advantage of the V-shape, already mentioned, is that when the elements are mounted in the terminal strip in alternating fashion the parallel arms of adjacent elements can be rather closely spaced, thus conserving terminal strip space and allowing a greater number of wire terminations in the same terminal strip length. Another factor contributing to space conservation is that because of the self support provided by the V-shape, less structure is needed in the terminal strip to support the terminal element. 
     In view of the above description, it is likely that modifications and improvements will occur to those skilled in the art which are within the scope of the appended claims.