Cable branch terminal for electrically connecting a main conductor to a branch conductor

Description

[0001] The present invention relates to a cable branch terminal for electrically connecting a particularly insulated main conductor to a branch conductor.

[0002] For example, to connect electrical systems of individual consumers to a main or trunk cable that is being laid or has already been laid near the consumer, it is common practice to install so-called branch joints. In the branch joints, at least one conductor of the branch cable is connected to the corresponding conductor of the trunk cable or main conductor via a cable branch terminal. To do this, the insulating and protective layers of the cables (conductor insulation, gusset filling, and cable sheath) must be partially removed and, after clamping, replaced by the insulation of the joint. Individual terminals and so-called compact branch terminals are used as terminals for this purpose.

[0003] Cable branch terminals of the type considered here typically have a primary insulation-piercing contact terminal with at least one contact screw guided in a clamping body and a device for cutting the primary insulation of a core of the main conductor, located at least partially opposite the end face of the contact screw. The device for cutting the primary insulation of a core of the main conductor typically has corresponding cutting edges designed to penetrate the insulation of the main conductor to establish an electrical connection with the electrical conductor of the main conductor.

[0004] The term "primary insulation" used here refers to the insulation of the individual cores, especially of a multi-core cable. The primary insulation consists of an electrically insulating material, especially plastic and / or paper. However, the plastic materials used for the primary insulation often differ from cable to cable in terms of the plastic material and / or the thickness of the plastic insulation. Especially recently, cables with cores covered with only a relatively thin primary insulation have been increasingly used in order to save material.

[0005] Apart from the different strengths (thicknesses) of the plastic insulation used as primary insulation, the plastic and / or paper materials commonly used as primary insulation have different mechanical and thermal properties that influence the force required to penetrate and penetrate the cutting edges of a cable branch terminal.

[0006] The cutting edges commonly used in cable branch terminals to cut the primary insulation of a core of a main conductor are generally designed to be too "aggressive" with regard to the electrical conductor of the main conductor, since the cutting edges not only penetrate the primary insulation when contacting the main conductor, but also pose the risk of damaging or penetrating the inner conductor of the main conductor.

[0007] The document US 5,816,844 A relates to a cable branch terminal according to the preamble of independent patent claim 1.

[0008] The publication DE 37 09 841 A1 relates to a cable branch terminal with a receiving space formed by a ring portion for a live cable main conductor, and with an elongated contact portion in which a threaded hole extending into the receiving space and carrying a milling screw is provided to penetrate the insulation of the main conductor. A clamping channel for receiving and contacting the conductor end of a branch conductor is provided in a lateral extension of the contact portion.

[0009] The present invention is based on the object of specifying a cable branch terminal for electrically connecting a main conductor, in particular an insulated one, to a branch conductor, wherein the risk is minimized that the inner conductor of the main conductor is weakened or damaged in an unreasonable manner during galvanic contact with the inner conductor of the main conductor.

[0010] This object is achieved by the subject matter of independent patent claim 1, which relates to a cable branch terminal comprising a headpiece carrying a pressure screw for the main conductor and a bow-shaped abutment detachably attached to the headpiece, against which the main conductor rests. A receptacle for the branch conductor, designed in particular as a bore, is formed in the headpiece.

[0011] According to embodiments of the cable branch terminal, it is provided that the bow-shaped abutment has at least one and preferably a plurality of in particular pyramid-shaped cutting teeth, at least in an area opposite the head piece.

[0012] By using individual cutting teeth, which in particular are at least substantially pyramid-shaped, a reliable galvanic contacting of the inner conductor of the main conductor is possible, even with different designs of the primary insulation of the main conductor, without, however, there being a risk that the inner conductor of the main conductor will be weakened or even penetrated during the galvanic contacting of the inner conductor of the main conductor.

[0013] According to the invention, the cable branch terminal has a head piece carrying a pressure screw for the main conductor and the bow-shaped abutment detachably fastened to the head piece, against which the main conductor is supported, wherein a receptacle for the branch conductor, in particular designed as a bore, is formed in the head piece.

[0014] The cable branch terminal according to the invention is characterized in particular in that the pressure screw is designed as a milling screw and has a spherical cap-shaped end region facing the main conductor, wherein a circular recess is formed in the spherical cap-shaped end region of the pressure screw.

[0015] According to the invention, the particularly circular recess is designed concentrically with respect to the longitudinal axis of the pressure screw.

[0016] The circular recess is designed as a blind hole in the spherical cap-shaped end region of the pressure screw and defines a cutting edge at least in part around its circumference for penetrating the insulation of the main conductor. The blind hole forms a reservoir for receiving the insulation of the main conductor separated by the cutting edge. In other words, when contact is made with the inner conductor of the main conductor, the blind hole in the spherical cap-shaped end region of the pressure screw receives at least a portion of the primary insulation of the main conductor punched out using the pressure screw designed as a milling screw. The spherical cap-shaped end region of the pressure screw serves in particular to radially outwardly displace the insulation material of the main conductor that is not accommodated by the blind hole serving as a reservoir.

[0017] Therefore, the cable branch terminal according to the invention offers an easy-to-implement but nevertheless effective way to reproducibly connect a main conductor galvanically to the cable branch terminal.

[0018] As already explained, the bow-shaped abutment of the cable branch terminal can have at least one and preferably a plurality of, in particular, pyramid-shaped cutting teeth in a region opposite the head piece. These cutting teeth are arranged in particular on a metal strip, which is inserted, in particular replaceably, into a bow region formed by the bow-shaped abutment.

[0019] This design makes it possible to adapt the cutting teeth of the particularly bow-shaped abutment in the most efficient way possible to different primary insulations of the main conductor in order to effectively penetrate the primary insulation and to be able to galvanically contact the wire or the inner conductor of the main conductor.

[0020] According to embodiments of the cable branch terminal according to the invention, the bow-shaped abutment has a bow which is at least substantially U-shaped in cross section, between the legs of which the main conductor is inserted or can be inserted, wherein the head piece of the cable branch terminal has at least one groove into which a hook-shaped ridge strip of the abutment engages.

[0021] In other words, the cable branch terminal is preferably designed in two parts, wherein the main conductor can be inserted between the legs of the U-shaped bracket, and wherein the head piece of the cable branch terminal is then detachably connected to the U-shaped bracket of the bracket-shaped abutment.

[0022] According to a further (unclaimed) aspect, the disclosure relates to a cable branch terminal which has a head piece carrying a pressure screw for a main conductor and a particularly bow-shaped abutment which is fastened to the head piece in a particularly detachable manner and against which the main conductor is supported.

[0023] The cable branch terminal according to this aspect of the disclosure is characterized in particular in that, for the attachment of a tool, in particular a screwdriver or a wrench, a pressure screw drive is assigned to the pressure screw, which is connected to a shaft region of the pressure screw at an end region of the pressure screw facing away from the main conductor.

[0024] The pressure screw drive is designed in particular as a component preferably made of a plastic material and connectable to the shaft area of ​​the pressure screw preferably via a force-locking and / or form-locking connection, in particular via a plug-in connection.

[0025] Since the pressure screw drive of the cable branch terminal is preferably formed from a plastic material, the cable branch terminal is particularly lighter to design compared to conventional cable branch terminals in which the pressure screw drive itself is formed from the same material as the material of the pressure screw.

[0026] According to embodiments of the cable branch terminal according to the invention, it is provided that a predetermined breaking point, in particular in the form of a material taper, for example in the form of a notch, perforation or scratch mark, is formed in a body of the pressure screw drive, which is designed to respond to a predetermined or definable torque exerted by the pressure screw drive on the shaft area of ​​the pressure screw in such a way that an operative connection between the pressure screw drive and the pressure screw is severed.

[0027] This design provides the decisive advantage that a clean break point can be achieved when the predetermined breaking point of the pressure screw drive is triggered, which is advantageous when the cable branch terminal is subsequently to be installed in a corresponding cable branch sleeve.

[0028] A preferred embodiment of the invention is described in more detail below with reference to the accompanying drawings.

[0029] They show: FIG. 1 schematically and in a partially transparent isometric view an exemplary embodiment of the cable branch terminal according to the invention without a main conductor; and FIG. 2 schematically and in a partially transparent, isometric sectional view the exemplary embodiment of the cable branch terminal according to the invention according to FIG. 1 with a main conductor contacted by the cable branch terminal.

[0030] The FIG. 1 and FIG. 2The cable branch terminal 1 shown consists of a head piece 6 made of brass, for example, which carries a pressure screw 2 for the main conductor 100 to be galvanically contacted. Furthermore, the cable branch terminal 1 has a particularly bow-shaped abutment 7, which is fastened to the head piece 6, in particular detachably, and against which the main conductor 100 rests.

[0031] The particularly bow-shaped abutment 7 has a bow which is at least substantially U-shaped in cross section, between the legs of which the main conductor 100 is inserted or can be inserted.

[0032] In particular, the headpiece 6 is detachably connected to the bow-shaped abutment 7. For this purpose, in the embodiment shown in the drawings, the headpiece 6 has corresponding grooves 9, into which a hook-shaped ridge strip 10 of the abutment 7 engages.

[0033] In the head piece 6 of the cable branch terminal 1 there is also a receptacle 14, designed in particular as a bore, for a branch conductor.

[0034] The cable branch terminal 1 according to the invention, as shown in the accompanying drawings using an exemplary embodiment, is characterized in particular in that the particularly bow-shaped abutment 7 has, at least in a region opposite the head piece 6, particularly pyramid-shaped cutting teeth 8, with the aid of which the primary insulation of the main conductor 100 can be effectively penetrated.

[0035] In this context, it is advisable that the pyramid-shaped cutting teeth 8 are arranged on a metal band, which is preferably inserted in an exchangeable manner into a bracket area formed by the particularly bracket-shaped abutment 7.

[0036] The exemplary embodiment of the cable branch terminal 1 according to the invention shown in the drawings is further characterized in particular in that the pressure screw 2 guided by the head piece 6 of the cable branch terminal 1 is designed as a milling screw and has a spherical cap-shaped end region 3 facing the main conductor 100, wherein a particularly circular recess 4 is formed in the spherical cap-shaped end region 3 of the pressure screw 2.

[0037] The particularly circular recess 4 in the spherical cap-shaped end region 3 of the pressure screw 2 is preferably formed concentrically with respect to the longitudinal axis of the pressure screw 2.

[0038] In the embodiment shown in the drawings, the particularly circular recess 4 in the spherical cap-shaped end region 3 of the pressure screw 2 is designed as a blind hole 5 in the spherical cap-shaped end region 3 of the pressure screw 2 and defines, at least in some areas, a cutting edge circumferentially for penetrating an insulation of the main conductor 100. The blind hole 5 itself forms a reservoir for receiving the insulation of the main conductor 100 separated by the cutting edge.

[0039] For attaching a tool, in particular a screwdriver or a wrench, a pressure screw drive 11 is assigned to the pressure screw 2, which is connected to a shaft region 13 of the pressure screw 2 at an end region 3 of the pressure screw 2 facing away from the main conductor 100.

[0040] The pressure screw drive 11 is designed as a component that is formed in particular from a plastic material and can be connected to the shaft region 13 of the pressure screw 2 preferably via a force-locking and / or form-locking connection, in particular via a plug-in connection.

[0041] In a body of the pressure screw drive 11, a predetermined breaking point 12 is formed, in particular in the form of a material taper, for example in the form of a notch, perforation or scratch mark, which is designed to respond to a predetermined or definable torque exerted by the pressure screw drive 11 on the shaft region 13 of the pressure screw 2 in such a way that an operative connection between the pressure screw drive 11 and the pressure screw 2 is severed.

[0042] The invention is not limited to the exemplary embodiment of the cable branch terminal 1 according to the invention shown in the drawings, but is limited only by the claims. List of reference symbols

[0043] 1Cable branch terminal 2Pressure screw 3Spherical cap-shaped end section of the pressure screw 4Circular recess 5Blind hole / reservoir 6Head piece 7Abutment 8Cutting tooth 9Head piece groove 10Burr strip of the abutment 11Pressure screw drive 12Predetermined breaking point 13Shaft section of the pressure screw 14Hole for a branch conductor 100Main conductors

Claims

1. Cable tapping clamp (1) for electrically connecting an, in particular, insulated main conductor (100) to a branch conductor, the cable tapping clamp (1) comprising: - a head piece (6) guiding a pressure screw (2) for the main conductor (100); and - a bow-shaped abutment (7) releasably connected to the head piece (6), the main conductor (100) being supported against said abutment; wherein a receptacle (14), which is configured in particular as a bore for the branch conductor, is configured in the head piece (6), characterized in that the pressure screw (2) is formed as a milling screw and has a spherical cap-shaped end region (3) facing the main conductor (100), wherein a circular recess (4) is formed in the spherical cap-shaped end region (3) of the pressure screw (2) , the circular recess (4) being concentric with respect to the longitudinal axis of the pressure screw (2), the circular recess (4) being designed as a blind hole (5) made in the spherical cap-shaped end region (3) of the pressure screw (2) and defining peripherally a cutting edge, at least in some regions, for penetrating an insulation of the main conductor (100), and the blind hole (5) forming a reservoir for receiving the insulation of the main conductor (100), which is separated by means of the cutting edge.

2. Cable tapping clamp (1) according to claim 1, wherein the bow-shaped abutment (7) has at least one and preferably a plurality of in particular pyramidal cutting teeth (8) at least in a region lying opposite the head piece (6).

3. Cable tapping clamp (1) according to claim 1 or 2, wherein the at least one in particular pyramidal cutting tooth (8), and preferably the plurality of in particular pyramidal cutting teeth (8) are arranged on a metal band which is inserted, and preferably interchangeably inserted, into a bow area formed by the bow-shaped abutment (7).

4. Cable tapping clamp (1) according to one of claims 1 to 6, wherein the bow-shaped abutment (7) has a bow which is at least substantially U-shaped in cross-section and between the legs of which the main conductor (100) is inserted or insertable, and wherein the head piece (6) has at least one groove (9) in which a hook-shaped burr strip (10) of the abutment (7) engages.

5. Cable tapping clamp (1) according to one of the claims 1 to 7, wherein a pressure screw drive (11) is associated with the pressure screw (2) for the attachment of a tool, in particular a screwdriver or a wrench, which pressure screw drive (11) is connected by a shaft region (13) of the pressure screw (2) to an end region (3) of the pressure screw (2) facing away from the main conductor (100), the pressure screw drive (11) being designed as a component which is formed in particular from a plastic material and can be connected to the shaft region (13) of the pressure screw (2) preferably via a force-fitting connection, in particular via a plugin connection.

6. Cable tapping clamp (1) according to claim 5, wherein a predetermined breaking point (12), in particular in the form of a material taper, for example in the form of a notch, perforation or scratch mark, is formed in a body of the pressure screw drive (11), which predetermined breaking point is designed to respond, at a predetermined or determinable torque exerted by the pressure screw drive (11) on the shaft region (13) of the pressure screw (2) in such a way that an operative connection between the pressure screw drive (11) and the pressure screw (2) is disconnected.