EP0599346B1 - Multiphase branch terminal - Google Patents

Description

The invention relates to a multiphase junction terminal for cables with a plurality of insulated phase conductors running in the longitudinal direction of the cable, with a divided body encompassing the cable, the parts of which can be clamped together and in which main contacts with teeth are arranged in isolated receptacles in corresponding receptacles for penetrating the insulation of the phase conductors, and with clamping parts inserted into the terminal body, which are assigned to the main contacts and are used for connecting branch conductors, first and second pairs of clamping parts for groups of phase conductors and branch conductors being provided in first and second housing halves.

Such a branch terminal is known for example from DE-As 23 35 654 and serves to connect connecting cables to a main cable laid in the ground, for example for a so-called house connection. Such connection connections must be possible without cutting the main cable, without interrupting the power supply and without stripping the individual conductors of the main cable. Furthermore, it is necessary that the corresponding connection work can be carried out in such a way that, on the one hand, reliable connections are made and, on the other hand, the installer cannot come into contact with live parts for safety reasons. Another requirement is that the security of the connections made must be reliably guaranteed for very long periods of many years.

In the branch terminal according to DE-AS 23 35 654, the respective branch conductors are each inserted into the receptacle of a contact piece and individually clamped with a clamping screw running transversely to the branch conductor. Each housing half accommodates a group of two phase conductors and two branch conductors. When all branch conductors have been connected, the two halves of the housing are connected with two screws. These two screws pull the two housing halves against each other, with corresponding teeth on the contact pieces penetrating the insulation of the phase conductor or the neutral conductor and ensuring the electrical connection from the wires of the main cable to the assigned wires of the branch cable.

Even if a branch terminal of this type may be suitable for a number of purposes, assembly is very laborious and time-consuming, since a total of six screws have to be tightened in order to make all the connections. It should not be neglected that the corresponding screws for clamping are not freely accessible during assembly, because of the rigidity of the Cables with the required cable cross sections must be tightened at least two screws from the bottom. It should be noted that the cable trenches that are opened for this purpose are only about 80 cm wide, so that the fitter has little room to move in the cable trench.

Under such conditions, the assembly of the branch terminal is associated with considerable difficulties, the tool having to be used very often. Unless the connection is carried out with great care and a correspondingly high expenditure of time, the security of the connections cannot be guaranteed.

The object of the invention is to provide a branch terminal of the type mentioned, which can be connected in a particularly convenient manner, without requiring specialist knowledge of the fitter, and at the same time ensures a high degree of security in the connections made.

The solution according to the invention is that a single through screw is provided as an actuator, which passes through the clamping parts and can be screwed into the other housing half from one housing half; and that between the through-screw and the clamping parts drivers predetermined maximum torque load capacity are provided, which at the same time form temporarily effective stops in the feed direction of the through-screw, so that when the through-screw is tightened, the pairs of clamping parts are first tightened by contacting the branch conductors and only afterwards when the through-screw is advanced the housing halves are tightened against each other while contacting the phase conductors. With the branch clamp according to the invention, the task is solved in a satisfactory and surprisingly simple manner, the fitter being able to attach the branch clamp with the single through screw in an advantageous manner so that he essentially passes through the through screw can operate, so that the branch clamp is easy to handle and connect for the fitter. Even if the phase conductors (both the actual phase conductors and the neutral conductors are understood here and below) due to the twist in the main cable at the connection point of the cable laid in the ground, they will not always be oriented so that the through screw is exactly vertical can usually be found, a position in which the through screw can be positioned and actuated at an angle of less than 45 ° with respect to the vertical. In these cases, too, the single through screw is easy to apply and operate and is easily accessible by the fitter even in the cable trench.

Since in the terminal according to the invention there are provided predetermined maximum torque load capacities, it is ensured that the branch conductors are reliably connected without any risk of damage to the branch conductors, because the maximum forces acting on the branch conductors are limited, the limit value depending on the materials and diameters of the branch conductors can be specified.

In the case of the clamp according to the invention, the drivers expediently consist of positive and / or non-positive complementary pairs of driver parts, in which the driver engagement breaks off when the predetermined maximum torque load capacity is exceeded.

In the case of the clamp according to the invention, both pairs of clamping parts can be tightened first by contacting the branch conductors, whereupon the phase conductors are then contacted.

In a special embodiment of the clamp according to the invention it is provided that the drivers, viewed in the longitudinal direction of the through screw, are arranged one behind the other in different planes, and that the through screw when actuated in a first position, it tightens a first pair of clamping parts until the assigned first driver tears off, then in a second lower position it tightens a second pair of clamping parts until the assigned second driver tears off, and only then in a third position with the second housing half comes into threaded engagement and pulls the housing halves against each other in order to make contact with the phase conductors. This further improves security when making contact.

In a special embodiment of the clamp according to the invention it is provided that the clamping parts have a threaded bushing or a nut on the through screw, the one component of the threaded bushing or nut on the one hand and the through screw on the other hand having a shear pin, while the other component has a complementary recess. Depending on the spatial conditions, the through screw in the area of the one housing half can have a radially projecting shear pin which engages in a radial groove of a bushing, while the through screw in the area of the other housing half has a radial groove, for example on the end face, which has a corresponding shear pin can be brought into engagement.

In a further development of the clamp according to the invention, it is provided that an insulating hollow wedge which can be driven between pairs of phase conductors lying one above the other and which has a tubular interior as a guide for the through screw, and an insulating transverse wedge which can be received by the hollow wedge transversely to the hollow wedge. The hollow wedge and the cross wedge ensure, in a manner known per se, permanent insulation of the phase conductors from one another when these are struck by the teeth of the main contacts. The hollow wedge also has the function of guiding the through screw of the clamp according to the invention, at least in the central region of the clamp.

The hollow wedge and the cross wedge are designed in such a way that they can be easily driven into the space between the phase conductors and at the same time assume a reliable fit between the phase conductors. Corresponding details emerge from the subclaims and the detailed description below.

The through screw expediently has an engagement part at one end for an actuating tool, which engages via a torque limiting device to the shaft of the through screw. This ensures that a predetermined force is also applied to the phase conductors, which ensures reliable contact and ensures defined conditions inside the terminal. Further details of the engagement part of the through screw are explained below and specified in the subclaims.

In a further development of the clamp according to the invention, it is provided that each pair of clamping parts has a movable pressure piece, each with two branch contacts, which, when the through screw is tightened, can be moved in the longitudinal direction at the same time against an abutment formed by the main contacts, around the branch conductors between the main contacts and the branch contacts to clamp. The branch contacts and the main contacts are expediently designed as profile pieces, wherein the opposite sides of the branch contacts and the main contacts can have concave surfaces of complementary shape in cross-section for fixing branch conductors.

In the case of the terminal according to the invention, the main contacts and the branch contacts form continuous channels running between one another in the longitudinal direction of the cable and in the middle there are removable, transverse dividing walls. In this way, two branch conductors can be accommodated from opposite sides in each continuous channel. Alternatively, loop-through branch conductors can be accommodated in these channels if the Partitions have been broken out. The dividing walls can also be arranged at the end of the channels in order to serve as a stop for the branch conductors inserted from the opposite side.

In the case of the terminal according to the invention, branch conductors with appropriately stripped ends or non-stripped branch conductors can be connected. In the latter case in particular, it is provided that the main contacts and / or the branch contacts are provided with teeth or cutting edges on their sides opposite one another with respect to a branch conductor for penetrating insulation on branch conductors.

In the terminal according to the invention, at least one component of the main contact and the branch contact has a concave, in particular an arc-shaped or elliptical, profile on its opposite sides in cross section, this shape being provided for all channels for receiving the branch conductors.

In the clamp according to the invention, the pressure piece is expediently arranged with a certain play transversely to the through screw, so that a pendulum-shaped contact pressure is exerted on the branch contacts. In this way, any tolerances in the dimensions or the spatial position of the conductors can be compensated.

The maximum tightening torques for the pressure pieces on the one hand and the housing halves on the other hand can be specified independently of one another, expediently such that smaller forces act on the branch conductors than on the housing halves, with which the phase conductors are finally contacted through their insulation. For example, these maximum torques can be 20 Nm or 30 Nm.

The pressure pieces and associated threaded bushings can be designed in various ways and can be in engagement with one another, with corresponding details being apparent the subclaims and the description below.

In the case of the clamp according to the invention, one housing half is provided with a molded thread or a built-in or non-rotatably fastened nut which serves to receive the threaded end of the through screw. The attachment and dimensioning of this nut or thread depends on the spatial conditions and the forces to be applied. Further details can be found in the description below.

In this context, it proves to be expedient if the thread of the through screw and the associated receiving thread have a smaller diameter than the other components used for clamping conductors through which the through screw passes. This allows the through screw to be carried out easily and is protected against damage at its threaded end.

Fig. 1

eine auseinandergezogene schematische Seitenansicht im Schnitt einer erfindungsgemäßen Klemme mit ihren Einzelheiten;

Fig. 2

eine zusammengestzte erfindungsgemäße Klemme mit fertig kontaktierten Leitern in Richtung der Kabellängsachse, in deren linker Hälfte der jeweils größte Haupt- und Abzweigleiterquerschnitt dargestellt ist, während im rechten Halbschnitt die kleinsten verklemmbaren Querschnitte der Leiter dargestellt sind;

Fig. 3

Klemme gemäß Fig. 2, Ansicht quer zur Kabellängsachse;

Fig. 4

schematische Draufsicht im Schnitt von Hohlkeil und Querkeil zwischen den Phasenleitern;

Fig. 5a bis 5c

eine schematische Darstellung der einzelnen Schritte zur Montage der erfindungsgemäßen Klemme;

Fig. 6 bis 8

schematische Seitenansichten im Schnitt von verschiedenen modifizierten Ausführungsformen der erfindungsgemäßen Klemme.

The invention is explained in more detail below, also with regard to further features and advantages, on the basis of the description of exemplary embodiments and with reference to the accompanying drawings. The drawings show in

Fig. 1

an exploded schematic side view in section of a clamp according to the invention with its details;

Fig. 2

a composite terminal according to the invention with fully contacted conductors in the direction of the longitudinal axis of the cable, in the left half of which the largest main and branch conductor cross section is shown, while the right half section shows the smallest clampable cross sections of the conductors;

Fig. 3

2, view transversely to the longitudinal axis of the cable;

Fig. 4

schematic plan view in section of hollow wedge and cross wedge between the phase conductors;

5a to 5c

a schematic representation of the individual steps for assembling the clamp according to the invention;

6 to 8

schematic side views in section of various modified embodiments of the clamp according to the invention.

In the following, reference is first made to FIG. 1 in order to explain the structure of the branch terminal according to the invention and its components in detail. A terminal 10 consists of two housing halves 12 and 14, which have an approximately U-shaped cross-section and are provided with corresponding recesses in their interior in order to accommodate contacts with associated insulation and to store them practically non-rotatably. For this purpose, insulating parts 16 and 18, for example, are arranged in the housing halves 12 and 14, into which main contacts 20 with corresponding projections can be inserted non-rotatably. The main contacts 20 have cutting edges or teeth 22 pointing inside the terminal 10 for penetrating insulations on phase conductors to be contacted, which are shown in FIG. 1 as cutting edges.

The main contacts 20 are opposite branch contacts 24, which form channels 23 for receiving branch conductors with their opposing concavely curved contact surfaces. Thrust pieces 30 and 32 are T-shaped in cross section and provided with insulating pieces 26 and 28, on which the respective branch contacts 24 sit. The shape of the pressure pieces 30 and 32 ensures a positive fit of the branch contacts 24. Each pressure piece 30 or 32 carries a pair of branch contacts 24, which are opposite a pair of main contacts 20.

1, the upper pressure piece 30 has a through opening 31 and a guide cylinder 33 with a larger diameter for receiving a threaded bushing 34, which has an external thread 38 at its upper end and is seated with its lower end in the guide cylinder 33 of the pressure piece 30 . The external thread 38 of the threaded bushing 34 can be screwed into an internal thread 42 in the upper region of the housing half 12, a recess being provided above the internal thread 42, which forms a receptacle 80 for a spring 78, which consists, for example, of a package of disc springs.

The lower pressure piece 32 in FIG. 1 has an internal thread 44 into which a threaded bushing 36 with its external thread 40 can be screwed. The lower end of the threaded bush 36 is cylindrical in shape on the outer circumference and is received by a sleeve 50 which is inserted into a receptacle 52 in the lower housing half 14. This sleeve 50 forms a bearing for the threaded bushing 36.

A hollow wedge 54 with an associated transverse wedge 66 can be seen between the two housing halves 12 and 14, which can be plugged into one another and form a cross-shaped insulation between the phase conductors of a cable to be contacted, which is shown in FIG. 4. The hollow wedge 54 has at its lower end a tip 56 which connects to the main body of the hollow wedge 54 via a predetermined breaking point 58. The hollow wedge 54 has vertically extending teeth 64 on its outer circumference for penetrating the insulation of the main conductors, as well as a recess 60 in its central region which serves to receive the transverse wedge 66. A tubular interior 62 of the hollow wedge 54 forms a through opening for a through screw 70 described below. The transverse wedge 66 has outer teeth 68 and, together with the hollow wedge 54, forms a cruciform arrangement for the positioning and insulation of the phase conductors shown in FIG. 4. The transverse wedge can be fork-shaped and inserted into the hollow wedge 54 in lateral recesses 60, which, in relation to FIG. 1, follow one another in a plane transverse to the plane of the drawing lie. Alternatively, the cross wedge 66 can be plate-shaped with a through hole and inserted transversely into the hollow wedge 54 through a central recess in the hollow wedge 54, the arrangement being such that the tubular interior 62 and the through hole of the cross wedge 66 are flush with one another.

The shape of the hollow wedge 54 is chosen so that it can be easily driven between superimposed pairs of conductors of the main cable. For this purpose, the breakable tip 56 is provided, which is removed after the hollow wedge 54 has been driven in. In plan view, the hollow wedge 54 expediently has a shape that tapers towards the ends, for example in the form of the contour of a boat.

In the upper area of FIG. 1, the through screw 70 can be seen, which has an engagement part 76, a predetermined breaking point 74, a head part 75, a shaft 71 and a threaded end 72 from top to bottom. The counterpart to the threaded end 72 is formed by a nut 82 under the housing half 14. This nut 82 can be non-rotatably attached to the housing half 14, for example can be received in a form-fitting manner. Alternatively, the nut 82 can be replaced by a thread that is cut or embedded in the body of the threaded part 14.

At the lower end of the through screw 70, a groove 73 can be seen which runs in the radial direction. Such a groove 73 is designed so that it can be brought into engagement with a driver 48 which is attached to the lower threaded bush 36 and is designed for a maximum torque provided. The threaded bushing 34 is equipped with a corresponding driver 46 which can be driven by a counterpart of the through screw 70. Here the threaded bushing 34 can carry a radially inwardly projecting shear pin which can be brought into drive engagement in a bore 77 of the through screw 70.

Of course, the drivers between the through screw on the one hand and the threaded bushings 34 and 36 are not limited to this embodiment. Rather, constructive measures are possible in which the threaded bushings have radial grooves which can be brought into engagement with corresponding shear pins of the through screw 70. Of course, the drivers can also consist of other positive or non-positive complementary pairs of driver parts, which are in engagement with one another by friction or corrugations, the driver engagement then tearing off or tearing off when a predetermined maximum torque load capacity is exceeded.

In the embodiment according to FIG. 1, the through screw 70 has an engagement part 76 in the form of an external hexagon, which can be actuated with a corresponding, attachable wrench. In the manner shown, a predetermined breaking point 74 can be provided between the engagement part 76 and the shaft 71 in order to form a torque limiting device. Alternatively, a torque wrench can be used to tighten the through screw 70. In another embodiment, not shown, the engagement part 76 is provided with an internal hexagon recess, which tears out or expands when a predetermined maximum torque is exceeded. In addition, the engagement part 76 can consist of electrically insulating material or be coated with it.

The head part 75 on the through screw 70 forms an abutment for the spring 78 and can be provided with an external hexagon, the diameter of which differs considerably from the diameter of the engagement part 76. This ensures that after the attacking part 76 has been torn off, there is no accidental further tightening or loosening of the through screw 70 with the same actuating tool. The head part 75 can optionally be used to open the clamp 10 at a later time with another tool.

In the clamp according to the invention, the pressure pieces 30 and 32 are designed as T-shaped parts which are transverse to the through screw 70 extending bending beams and thus exert an elastic contact pressure on the branch contacts 24. This allows existing tolerances to be compensated for. The threaded bushings 34 and 36 can also have a spherical bearing surface at their ends in order to allow a certain tilting of the pressure pieces 30 and 32 into engagement with the branch conductors to be contacted. The spring 78 in the upper region of the housing half 12 ensures long-term maintenance of the contact pressure, which can decrease without a spring element, for example due to the creeping deformation of aluminum cable conductors or as a result of other setting processes.

Fig. 2 shows the clamp of FIG. 1 in the fully assembled state. The hollow wedge 54 without its chipped tip 56 and the transverse wedge 66 are arranged in a cruciform arrangement between phase conductors 84, while branch conductors 88 are clamped between the respective pairs of main contacts 20 and 24. The through screw 70 passes through the aligned through openings of the housing halves 12 and 14, the threaded bushings 34 and 36, the pressure pieces 30 and 32 and the hollow wedge 54 and is screwed with its external thread 72 into a nut 82. The intended maximum torque was reached when the through screw was tightened, so that the engagement part 76 is torn off over the predetermined breaking point. In Fig. 2, therefore, only the head part 75 can be seen above the spring 78, which sits on the upper threaded bushing 34. In the manner shown, the cutting edges 22 of the main contacts 20 have penetrated through the insulations 86 of the phase conductors 84, so that the required contact between the phase conductor 84 on the one hand and the branch conductor 88 on the other hand is established via the respective main contact 20.

The branch contacts 24 and the main contacts 20 are designed as profile pieces and have concave surfaces of complementary shape in cross section on their opposite sides for fixing the branch conductors 88, which are seated in corresponding continuous channels 23. The pressure pieces 30 and 32 with their branch contacts 24 are non-rotatably arranged between adjacent pairs of main contacts 20, so that the branch contacts 24 are moved in the axial direction of the through screw when they are driven by the through screw 70. If the driver 46 or 48 is torn off, the pressure piece remains in the position reached and presses its branch contacts against the respective branch conductors. The inner edges of the main contacts 20 form lateral guides for the branch contacts 24. A certain lateral play is provided between the branch contacts 24 and the main contacts 20 for this feed movement, the branch contacts 24 being able to be advanced relative to the main contacts 20 until, in extreme cases, main contact and branch contact 24 abut against each other. In this way, branch conductors with very small cable cross sections can also be reliably clamped without changing the design of the terminal 10. It only changes the length of the feed path of the pressure pieces with the corresponding branch contacts.
The assembly of such a clamp according to the invention is explained in more detail with reference to FIGS. 5a to 5c.

As FIG. 5 a shows, the hollow wedge 54 is first driven in from above between pairs of phase conductors 84 lying one above the other. Then its tip 56 is cut off, so that only the body of the hollow wedge 54 sits between the phase conductors 84. The cross wedge 66 is then inserted between adjacent pairs of phase conductors in the recess 60 of the hollow wedge 54.

Fig. 5a also shows the upper half of the terminal 10. The housing half 12 can be seen in which two main contacts 20 opposite branch contacts 24 are arranged. The through screw 70 engages through the through hole in the threaded bushing 34 and the pressure piece 30 and is engaged with the driver 46 with the threaded bushing 34. The lower end of the through screw 70 can now be pushed through the tubular interior 62 of the hollow wedge 54.

5b shows the upper half of the clamp 10, which is inserted through the hollow wedge 54, with jammed branch conductors 88. In the next phase of assembly, the lower housing half 14 of the clamp 10 can be plugged in. It can be seen that in the lower part of the driver 48 is not yet in engagement with the groove 73 at the end of the through screw 70. There are still no branch conductors 88 in the channels 23 of the lower part between the main contacts 20 and the branch contacts 24.

5c shows the next assembly step, the through screw 70 having already applied the corresponding pressure pieces via the threaded bushings, so that the branch conductors 88 are clamped between corresponding pairs of main contacts 20 and branch contacts 24. The through screw 70 has therefore assumed a lower position. However, the threaded end 72 of the through screw 70 is not yet in engagement with the nut 82, so that the cutting edges or teeth 22 of the main contacts 20 have not yet penetrated the insulations 86 of the phase conductor 84.

Fig. 2 shows the finished assembly state, wherein the housing halves 12 and 14 have reached their end position in which the main contacts 20 are engaged with the phase conductors in the required manner. Since the predetermined maximum torque for the engagement part 76 has been reached, it is torn off. The attack part 76 and the tip 56 of the hollow wedge 54 form waste parts which are considered as proof of a proper jamming after completion of the assembly.

6 to 8 show special configurations in the fully assembled state of the clamp according to the invention.

6 shows a modified special embodiment of the clamp according to the invention. The left part of FIG. 6 shows the situation for a branch conductor 88 with a small cross section, while the right half in FIG. 6 shows the situation for branch conductor 88 with a large cross section. In this case, the phase conductors 84 have the same cross sections.

6, a nut 100 can be seen on the upper side of the housing half 12, which nut is in threaded engagement with an external thread 106 of a socket 102. The housing half 12 has a through bore 108, which forms a free passage for the external thread 106 of the bush 102, which has transverse arms 104 in its lower region. The arms 104 carry main contacts 20, while in this case the branch contacts 24 are non-rotatably supported in the housing halves 12 in corresponding receptacles. The housing half 12 forms a pressure part in this case.

A bushing 112 can be seen in the lower area of FIG. 6, which has an external thread 116 and an internal thread 44. The component with the projecting arms 114 is provided with an internal thread 42 and carries corresponding main contacts 20. The external thread 116 of the socket 112 engages through a through hole 118 in the housing half 14 into the component with the internal thread 42.

In the arrangement according to FIG. 6 there is a fine-toothed grooving 25 on the connection contacts 24 and the main contacts 20 to improve the contact. The fine-toothed grooving 25 can of course also be provided in the other embodiments of the terminal described above or below, even if these are shown in the drawing is not specifically shown.

In the embodiment according to FIG. 6, a first driver 46 is provided between the through screw 70 and the nut 100. As a result of this entrainment engagement, the nut 100 is continuously screwed onto the external thread 106 of the socket 102 during assembly, so that the housing part 12 with the connecting contacts 24 is moved against the main contacts 20 and thereby clamps the branch conductors 88 located between them. When the first driver is torn off, the through screw 70 engages with the socket 112 and screws the socket 112 into the component with the internal thread 42, so that the branch contacts 24 are moved against their main contacts 20 in the housing half 14, the corresponding branch conductors 88 are clamped.

If the driver 48 is torn off, the threaded end 72 of the through screw 70 can engage with the internal thread 44 of the bush 112 and thereby pull the two housing halves 12 and 14 against one another. Depending on the diameter of the branch conductors 88, the through screw 70 emerges more or less from the lower housing half 14.

7 shows a further embodiment of the clamp according to the invention. In the two housing halves 12 and 14, main contacts 20 are used in corresponding recesses provided with insulating parts 16 and 18, which are provided with recesses for receiving branch conductors 88. In cross section, these cutouts have the shape of elongated holes 124, which are provided with openings 126 on the inside facing the through screw 70. The pressure pieces 30 and 32 engage with their possibly angled down arms through these openings 126 into the elongated holes 124. The threaded bushings 34 and 36 are pivotably mounted on the pressure pieces 30 and 32 made of insulating material. For this purpose, the threaded bushings 34, 36 and the pressure pieces 30, 32 have complementary concave and convex contact surfaces in the embodiment in FIG. 7. The threaded bushings 34 and 36 are with their external threads 38 and 40 screwed into corresponding internal threads of the two housing halves 12 and 14 and can be acted upon by the through screw 70 via drivers 46 and 48.

In the embodiment according to FIG. 7, the pressure pieces 30 and 32 are formed in one piece with the branch contacts 24 and can be provided with schematically indicated teeth or cutting edges on their contact areas opposite the branch conductors. The right half of FIG. 7 shows the situation for branch conductors 88 with a large cross section, while the left half in FIG. 7 shows the positioning of the parts within the clamp when the branch conductors 88 have small diameters. It can be seen that in this case too, a large number of branch conductors 88 with different cross sections can be clamped with one design. The main contacts 20 have trough-shaped areas in which the branch conductors 88 adjust themselves. If the branch contacts 24 are brought into clamping engagement, the branch conductors 88 cannot undesirably dodge.

For this purpose, in the embodiment according to FIG. 7, the main contacts 20 have, in cross section, approximately circular troughs 130 for the self-aligning reception of the branch conductors 88, while the opposite branch contacts 24 have contact areas 132 which are narrower in cross section than the troughs 130. In this way, the pressure pieces 30 with their branch contacts 24 can be pushed sufficiently far into the troughs 130 in order to adapt to any conventional cross sections of branch conductors 88.

8 shows a further embodiment of the clamp according to the invention. The main contacts 20 are non-rotatably supported with insulating parts 16 and 18 in receptacles of the housing halves 12 and 14. The main contacts 20 for contacting the branch conductors 88 have angular regions with contours that are circular segment in cross section. They lie opposite angular branch contacts 24 with contours of circular segment shape in cross section, the branch contacts 24 being seated on transversely projecting arms of pressure pieces 148 and 158. The thrust pieces 148 and 158 have internal threads 150 and 160 for engagement with corresponding external threads 146 and 156 on threaded bushes 142 and 152. The threaded bushes 142 and 152 are provided at their upper ends with ring flanges 144 and 154, which form stops or supports as is results from Fig. 8.

8, the upper ring flange 144 of the threaded bush 142 sits on the housing half 12 and can be driven by the through screw 70, the threaded bush 142 reaching unhindered through a corresponding recess in the housing half 12. When the through screw 70 is actuated, the pressure piece 148 can be moved upward against the branch conductors 88, while the pressure piece 158 can be moved downward against the corresponding branch conductors 88. The conditions for a branch conductor 88 with a small cross section are shown on the left in FIG. 8, while the remaining clamping areas for branch conductors 88 are drawn with large cross sections. The drivers 46, 48 and the groove 73 have the same function as already explained in connection with FIG. 1. The housing halves 12 and 14 are also screwed together in the same manner as already explained in connection with FIG. 1.

Claims (35)

1. A multiphase branch terminal for cables with several insulated phase conductors (84) extending in the longitudinal direction of the cable,

   - comprising a split terminal body which encloses the cable, the parts of which can be clamped together and in which main contacts (20) are arranged insulated from each other in corresponding holders, the said main contacts comprising teeth (22) for penetrating the insulations of the phase conductors (84), and

   - comprising terminal parts which are inserted into the terminal body which are associated with the main contacts (20) and which serve for the connection of branch conductors (88), first and second pairs of terminal parts being provided in first and second housing halves (12, 14) for groups of phase conductors (84) and branch conductors (88),

   characterised

   - in that there is provided as an operating element a single through-bolt (70) which passes through the terminal parts and can be screwed from one housing half (12) into the other housing half (14),

   - and in that between the through-bolt (70) and the terminal parts are provided drivers (46, 48) of a preset maximum torque loading capacity which at the same time temporarily form effective stops in the insertion direction of the through-bolt (70), so that when the through-bolt (70) is tightened, the pairs of terminal parts are tightened one after the other, contacting the branch conductors (88), and only then, as the through-bolt (70) is inserted further, are the housing halves (12, 14) tightened up firmly together, contacting the phase conductors (84).
2. A terminal according to claim 1, characterised in that the drivers are composed of positively locking or forcibly locking complementary pairs of driver parts, the driver engagement breaking off when the preset maximum torque loading capacity is exceeded.
3. A terminal according to claim 1 or 2, characterised in that the drivers, viewed in the longitudinal direction of the through-bolt (70), are arranged one behind another in different planes, and in that when it is operated, the through-bolt (70) in a first position tightens the first pair of terminal parts until the associated first driver (46) breaks off, then in a second position further down tightens a second pair of terminal parts until the associated second driver (48) breaks off, and only then in a third position comes into threaded engagement with the second housing half (14) and draws the housing halves (12, 14) together.
4. A terminal according to one of claims 1 to 3,
   characterised in that the terminal parts have a threaded bush (34, 36) or a nut on the through-bolt (70), one component of the threaded bush or the nut, on the one hand, and the through-bolt, on the other hand, having a shear pin (46, 48), and the other component having a complementary recess.
5. A terminal according to one of claims 1 to 4,
   characterised by an insulating hollow key (54) which may be driven in between pairs of phase conductors (84) located one above the other, and which has a tubular interior (62) serving as guide for the through-bolt (70), and by an insulating cotter (66) which may be received by the hollow key (54) transversely to the hollow key (54).
6. A terminal according to claim 5, characterised in that the cotter (66) is fork-shaped and may be inserted into lateral recesses (50) of the hollow key (54).
7. A terminal according to claim 5, characterised in that the cotter (66) is laminar with a through-hole and may be inserted through an opening in the hollow key (54) transversely into the hollow key (54), the tubular interior (62) and the through-hole lining up with one another.
8. A terminal according to one of claims 5 to 7,
   characterised in that the hollow key (54) holds two opposing cotters.
9. A terminal according to one of claims 5 to 8,
   characterised in that the hollow key (54) has an outer contour in the shape of a ship's hull which tapers both in the longitudinal direction of the cable and in the driving-in direction of the hollow key (54).
10. A terminal according to one of claims 5 to 9,
    characterised in that at its end the hollow key (54) has a tip (56) connected to the shaft of the hollow key (54) by way of a predetermined breaking point (58).
11. A terminal according to one of claims 1 to 10,
    characterised in that the through-bolt (70) has an application part (76) at one end which is joined to its shaft (71) by way of a torque limiting device.
12. A terminal according to claim 11, characterised in that the application part (76) has an external hexagon head which is joined to the shaft (71) by way of a predetermined breaking point (74).
13. A terminal according to claim 11, characterised in that the application part (76) has an internal hexagonal recess which is expanded when a predetermined maximum torque is exceeded.
14. A terminal according to one of claims 11 to 13, characterised in that the application part (76) is made of electrically insulating material or is covered therewith.
15. A terminal according to one of claims 1 to 14,
    characterised in that below the predetermined breaking point (74) the through-bolt (70) has a head part (75), possibly with an external hexagon, which forms an abutment for a spring (78) between the housing part (12) and the through-bolt (70).
16. A terminal according to one of claims 1 to 15,
    characterised in that each pair of terminal parts has a movable thrust piece (30, 32) with two branch contacts (24) respectively, which, when the through-bolt (70) is tightened, may be moved simultaneously in the longitudinal direction thereof towards an abutment formed by the main contacts (20), so as to clamp branch conductors (88) between main contacts (20) and branch contacts (24).
17. A terminal according to one of claims 1 to 16,
    characterised in that the branch contacts (24) and the main contacts (20) are shaped pieces.
18. A terminal according to one of claims 1 to 17,
    characterised in that the mutually opposite sides of the branch contacts (24) and main contacts (20) have concave surfaces which are complementarily shaped in cross-section for fixing branch conductors (88) in position.
19. A terminal according to one of claims 1 to 18,
    characterised in that between them the main contacts (20) and the branch contacts (24) form continuous channels (23), extending in the longitudinal direction of the cable, which are provided with removable, transversely-extending partitions.
20. A terminal according to one of claims 1 to 19,
    characterised in that the main contacts (20) and/or the branch contacts (24) are provided with teeth (25) on their mutually opposite sides with respect to a branch conductor (88), for penetrating insulations on branch conductors (88).
21. A terminal according to one of claims 1 to 20,
    characterised in that at least one component of the main contact (20) and the branch contact (24) has a concave profile, more particularly a circular or elliptical profile, in cross-section on the mutually facing sides thereof.
22. A terminal according to one of claims 16 to 21,
    characterised in that the thrust piece (30, 32) is T-shaped in cross-section and has flexible bars extending transversely to the through-bolt (70) which exert a resilient bearing pressure on the branch contacts (24).
23. A terminal according to one of claims 16 to 22,
    characterised in that one thrust piece (32) has a through-opening for the through-bolt (70) and also an internal thread (44) which is in threaded engagement with the external thread (40) of a threaded bush (36) operable by the through-bolt (70).
24. A terminal according to claim 23, characterised in that at least the threaded bush (36) in the lower housing half (14) is mounted in a sleeve (50) in the housing half (14).
25. A terminal according to one of claims 1 to 24,
    characterised in that one thrust piece (30) has a through-opening (31) for the through-bolt (70) and a guide cylinder (33) with a larger diameter for a threaded bush (34), the external thread (38) of which is in threaded engagement with one housing half (12), and is operable by the through-bolt (70).
26. A terminal according to one of claims 1 to 25,
    characterised in that a housing half (12, 14) forms a thrust piece and bears branch contacts (24) set into it, in that a bush (102, 112) penetrates a through-bore (108, 118) in the housing half (12, 14) and bears main contacts (20) at one end, and in that at the other end the bush (102, 112) has an external thread (106, 116) on which is fitted a nut (100) or a component (114) which may be operated by the through-bolt (70) and which acts on the respective housing half (12, 14) in the direction of the main contacts (20).
27. A terminal according to claim 26, characterised in that one nut is formed by a bush (112) which has an internal thread (44) in engagement with the external thread (72) of the through-bolt (70).
28. A terminal according to one of claims 1 to 27,
    characterised in that a housing half (12, 14) forms the mounting for main contacts (20) which in cross-section are in the shape of an elongated hole (124) with an opening (126) on the interior side facing towards the through-bolt (70), in that a thrust piece (30, 32) provided at its ends with branch contacts (24) engages through the openings (126) of the main contacts (20), and in that a threaded bush (34, 36) operable by the through-bolt (70) and having an external thread (38, 40) may be screwed into one housing half (12, 14), advancing the thrust piece (30, 32).
29. A terminal according to one of claims 1 to 28,
    characterised in that the thrust piece (30, 32) is itself in one piece with the branch contacts (24) and is electrically insulated (128) from the parts of the terminal leading to the exterior.
30. A terminal according to one of claims 1 to 29,
    characterised in that main contacts (20) are in the shape of C-shaped hooks in cross-section which have a depression (130) for holding branch conductors (88) in a manner which is self-adjusting, and in that the branch contacts (24) located opposite have contact regions (132) which are narrower in cross-section than the depressions (130).
31. A terminal according to one of claims 1 to 30,
    characterised in that the main contacts (20) and the branch contacts (24) have regions which are angular in cross-section with contours in a circular segment shape and can be inserted into one another, continuously reducing the intervening space which they define.
32. A terminal according to one of claims 1 to 31,
    characterised in that the main contacts (20) and the branch contacts (24) are spaced apart transversely to the insertion direction of the through-bolt (70) and, optionally, move in opposite directions.
33. A terminal according to one of claims 1 to 32,
    characterised in that a rotatable threaded bush (142, 152) is provided which has a through-bore for the through-bolt (70) and an external thread (146, 156) with which a thrust piece (148, 158) is in threaded engagement, and in that the threaded bush (142, 152) is operable by the through-bolt (70), with the result that the thrust piece (148, 158) is movable relative to the threaded bush (142, 152) towards the main contacts (20).
34. A terminal according to claim 33, characterised in that the threaded bush (142, 152) has an annular flange (144, 154) which forms a plane or spherical stop or a support and with which the through-bolt (70) may be brought into operating engagement.
35. A terminal according to one of claims 1 to 34,
    characterised in that the thread (72) of the through-bolt (70) and the associated receiving thread have a smaller diameter than the remaining components which serve to clamp conductors and through which the through-bolt (70) passes.

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