Patent Publication Number: US-2020303847-A1

Title: Cable lug having a collar

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of PCT International Application No. PCT/EP2018/086029, filed on Dec. 19, 2018, which claims priority under 35 U.S.C. § 119 to European Patent Application No. 17209328.8, filed on Dec. 21, 2017. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a cable lug and, more particularly, to a cable lug for terminating an electric cable. 
     BACKGROUND 
     A cable lug is generally first mounted onto a conductor of an electric cable. Such a cable lug is, for example, known from EP 2 311 146 B1. The cable lug is then inserted into an insulator body. A lubrication element may be used to facilitate insertion of the cable lug. In addition, the insulating body often is widened upon the insertion, to ensure a water-tight and electrical sealing between the insulator body and the cable. The lubrication and the widening of the insulator body may push the insulator body from the cable. This may lead to a misalignment of the cable lug and may render the electric connection of the cable lug to an appliance, such as a switchgear, cumbersome. The insulating body and the cable lug need to be held in position manually. This, in turn, can be quite cumbersome in the field, if there is not enough handling space. 
     SUMMARY 
     A cable lug for terminating a cable and contacting an appliance includes a cable-side end section directly or indirectly contacting the cable, an appliance-side end section contacting the appliance, and a main body extending between the cable-side end section and the appliance-side end section. The main body has a collar that radially protrudes from the main body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be described by way of example with reference to the accompanying Figures, of which: 
         FIG. 1  is a sectional side view of a terminal assembly along a longitudinal axis of a cable lug of the terminal assembly; 
         FIG. 2  is a sectional side view of the terminal assembly of  FIG. 1  taken along line II-II with an alternative insulator body; 
         FIG. 3  is a perspective view of a cable lug according to another embodiment; 
         FIG. 4  is another perspective view of the cable lug of  FIG. 3 ; 
         FIG. 5  is a perspective view of a cable lug according to another embodiment; and 
         FIG. 6  is a sectional perspective view of the cable lug, taken along line VI-VI of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     In the following, the invention is explained in further detail by exemplary embodiments with reference to the drawings. In the drawings, the same reference numerals are used for elements that correspond to each other with respect to at least one of function and design. Moreover, it is to be understood that the combination of features shown in the figures and described herein below, is of exemplary nature only. Features of which the technical effect is not needed for a particular application can be omitted from the shown embodiments. Vice versa, features that are described above but are not shown to be comprised in the embodiments can be added, if the technical effect associated with that particular feature is needed for a specific application. 
     A cable lug  1  and a terminal assembly  2  according to an embodiment are shown in  FIG. 1 . The terminal assembly  2  includes the cable lug  1  and the insulator body  4 . 
     In  FIG. 1 , the cable lug  1  is shown inserted in an insulator body  4  which may be made of insulating material, in particular of an insulating material having at least limited elasticity. In the shown embodiment, the cable lug  1  is inserted into a cable lug receptacle  6  of the insulator body  4 . The insulator body  4  has an appliance receptacle  8  for receiving an appliance-side connector  10  which is only schematically indicated in  FIG. 1 . The appliance-side connector  10  may be part of an appliance  11 , such as a switchgear. If the insulator body  4  is to have shielding capabilities, the material of the insulator body  4  may be doped with a conductive filler and/or comprise at least one layer made from conductive material. 
     The insulator body  4 , as shown in  FIG. 1 , has an overall L-shape with two legs  12 ,  14  which may substantially extend perpendicular to one another. The cable lug receptacle  6  is located in a first leg  12 , whereas the appliance receptacle  8  is arranged in a second leg  14 . The L-shape may also be part of a larger insulator body  4  of a more complicated shape. 
     As shown in  FIG. 1 , the cable lug receptacle  6  and the appliance receptacle  8  intersect one another, so that the cable lug receptacle  6  opens into the appliance receptacle  8 . This allows establishing an electric connection within the insulator body  4  between the cable lug  1  and the appliance-side connector  10  e.g. using a bolt  16  for securing the contact between the appliance-side connector  10  and the cable lug  10 . 
     The cable lug  1  is mounted to a cable  18  having a conductor  20  either directly or indirectly. For mounting of the cable lug  1  onto the cable  18 , an adaptor or alignment element  22  may be arranged between the cable  18  and the cable lug  1 . The insulator body  4  may sealingly abut an outer surface  24  of the cable  18  in the cable lug receptacle  6 , so that both an interior  26  of the terminal assembly  2  can be sealed off from dirt and moisture, and an electrically sealed interface is guaranteed. A similar sealing may be affected between the insulator body  4  and the appliance-side connector  10 . 
     The cable lug  1 , as shown in  FIG. 1 , has a main body  27 , a cable-side end section  28  facing the cable  18  and an appliance side end section  30  facing away from the cable  18  and being located at the side where the appliance-side connector  10  is to be connected to the cable lug  1 . The main body  27  is located between the cable-side end section  28  and the appliance-side end section  30 . The main body  27  may be from a metal, such as copper or aluminum or an alloy containing at least one of copper and aluminum. 
     As shown in  FIG. 1 , the cable lug  1  or at least the main body  27  may have substantially rotational symmetry and be elongated in a direction of a longitudinal axis  32  which may coincide with or at least be parallel to an axis  34  of the cable lug receptacle  6 . The cable-side end section  28  has an opening  36  which may be parallel or even coaxial to the longitudinal axis  32  and extend into the cable lug  1  towards the appliance-side end section  30 . The opening  36  is configured to receive at least one of the conductor  20  of the cable  18  and the adaptor  22 . The longitudinal axis  32  extends from the cable-side end section  28  to the appliance-side end section  30 . 
     In order to fix the position of the cable lug  1  securely within the cable lug receptacle  6 , at least one collar  38  may be provided, as shown in  FIG. 1 . The collar  38  is located on the main body  27  and radially protrudes from the main body  27 , i.e. between the cable-side end section  28  and the appliance-side end section  30 . The collar  38  fastens the cable lug  1  onto the insulator body  4  by forming at least one of a friction lock  39   a , shown in  FIG. 1 , and a form lock  39   b , shown in  FIG. 2 . At least one of the collar  38  and the insulator body  4  is radially deformed as the collar  38  has an outer diameter  40  which is larger than an inner diameter  42  of the cable lug receptacle  6  at the final resting position of the cable lug  1  within the cable lug receptacle  6 , when the cable lug  1  is fully inserted and e.g. abuts the appliance receptacle  8  with its appliance-side end section  30  as shown. Due to the elastic deformation, an elastic restoring force is generated, which creates a normal force acting between the collar  38  and the insulator body  4 . The normal force in turn and thus creates friction lock  39   a  which holds the cable lug in place. At the same time, the collar  38  serves to center the cable lug  1  within the cable lug receptacle  6 . The cross-section of the collar  38  perpendicular to the longitudinal axis  32  may be circular, elliptical, ovoid or polygonal, or of any other shape, and in particular complementary to the cross-section of the interior of the insulator body  4 . 
     In  FIG. 1 , it is only schematically shown that the collar  38  is pressed into the deformed elastic material of the insulator body  4 . Of course, it is also possible that only the collar  38  is deformed or that both the collar  38  and the insulator body  4  are deformed. This will depend on the relative stiffnesses of the material of the collar  38  and the material of the insulator body  4  at the location where the collar  38  comes to rest within the cable lug receptacle  6 . 
     The main body  27 , as shown in  FIG. 1 , has a cylindrical section  44 , which may in particular have a circular cross section. The cylindrical section  44  may surround the opening  36 . The cylindrical section  44  may be located between the appliance-side end section  30  and the collar  38 . In the cylindrical section  44 , at least one radially extending threaded hole  46  may be located, in which a screw  48  may be received to clamp whatever is received in the opening  36 . In order to avoid damage of the insulator body  4  due to any part of the screw  48  protruding from the cylindrical section  44  or due to the rim of the threaded hole  46 , the insulator body  4  is spaced apart radially from the cylindrical section  44  at the location, where the threaded hole  46  is arranged. Alternatively or additionally, the cylindrical section  44  may be a crimp section, which is configured to be crimped around the conductor  20 . 
     The collar  38  ensures that the insulator body  4  cannot touch the threaded hole  46  or the screw  48 , and/or a sharp edge of a crimped cylindrical section  44 , by acting as a spacer between the cylindrical section  44  and the insulator body  4 . The collar  38  may be located at or close to the end of the cylindrical section  44  which end faces towards the appliance-side end section  30 . The end may be spaced apart between 0.5 and 2 material thicknesses from the collar  38 , where material thickness is determined in the longitudinal direction  32 . 
     As indicated by the phantom lines in  FIG. 1 , at least one or more additional collars  38  may be provided spaced apart from the collar  38  in the longitudinal direction  32 . This allows keeping the insulator body  4  spaced apart from the cable lug  1  at all critical sections, where the insulator body  4  may be damaged. The collar  38  or an additional collar  38  may be located at any other position in the longitudinal direction  32 , e.g. at the cable-side end  28  or between the cable-side end  28  and the appliance-side end  30 . 
     As shown in  FIG. 1 , the cable lug  1  has a protrusion  50 , which protrudes from the main body  27  along the longitudinal axis  32 . In an embodiment, the cylindrical section  44  if present, the collar  38  and the protrusion  50  are all coaxial. The protrusion  50  may have a smaller outer diameter than the cylindrical section  44 , if present, and the cylindrical section  44  may have a smaller outer diameter than the collar  38 ; the appliance-side end section  30  has a smaller outer diameter than the cable-side end section  28 . The collar  38  may constitute the largest outer diameter  40  of the cable lug  1 . 
     The protrusion  50  is an electrical connector which allows to establish electric contact with the appliance or the appliance connector  10 . The protrusion  50  has an opening  52 , which may be a threaded or unthreaded through hole. The axis of the opening  52  coincides with an axis  54  of the appliance receptacle  8 ; perpendicular to the longitudinal direction  32 . The bolt  16  may reach through the opening  52 . 
     As shown in  FIG. 1 , the collar  38  may be arranged between the cable-side end section  28  and the appliance-side end section  30  of the cable lug  1 . In particular, the collar  38  may be located at a base  56  of the protrusion  50 , where the protrusion  50  joins the main body  27 . A front face  58  of the collar  38  establishes a transition from the protrusion  50  to an outer, circumferential face  60  of the collar  38 . The front face  58  faces radially outwards and extends circumferentially around the longitudinal direction  32 . The front face  58  may be slanted away from the cable-side end section  28  towards the appliance-side end section  30  with decreasing radius to facilitate insertion of the cable lug  1  into the insulator body  4 . The front face  58  may be dome-shaped and/or be frustoconical at least in parts, in particular at its radially outer end. A rear face  62  of the collar  38  faces towards the cable-side end section  28 . The rear face  62  may be substantially perpendicular to the longitudinal axis  32  or, e.g. in sections, be slanted towards the appliance-side end section  30 . The collar  38  can be used to align a position of the protrusion  50  with respect to the insulating body  4 . 
     As described above, the cable lug  1  may be secured within the cable lug receptacle  6  by at least one of a form lock  39   b  and a friction lock  39   a . In  FIG. 2 , an exemplary embodiment is shown, which instead of or in addition to the frictional lock  39   a  shown in  FIG. 1  uses a form or positive lock  39   b . To establish such a form lock  39   b , the insulator body  4  has at least one locking element  64  which is configured to engage the collar  38  e.g. by a snap-fit. For example, the locking element  64  may be a radially inwardly protruding locking protrusion which is slanted at its side facing away from the appliance receptacle  8  to facilitate passing of the cable lug  1 , in particular of the collar  38 . To improve centering of the cable lug  1  within the cable lug receptacle  6 , the collar  38  abuts the interior of the cable lug receptacle  6  and the locking element  64  abuts the exterior of the cable lug  1  when the form lock  39   b  has been established. Of course, other locking elements  64  than shown in  FIG. 2  may be used, such as, for example, a circumferential groove in the cable lug receptacle  6 , in which the collar  38  is received. 
     As can be seen further in  FIG. 2 , the insulator body  4  may comprise several layers of different material. 
       FIGS. 3 and 4  show a cable lug  1 , in which the collar  38  does not have a circumferential face  60 , or at least a substantial circumferential face  60 , but rather forms a circumferential, tapering rib due to a dome-shaped front face  58 . The collar  38  is formed monolithically with the main body  27 . Nonetheless, the collar  38  and the remainder of the cable lug  1  need not to be of the same material. For example, one of a ready-made cable lug  1  or/and collar  38  may be put into a mold and the other one of the collar  38  and the cable lug  1  may be cast onto the already existing part. 
     It is further shown in  FIGS. 3 and 4  that the collar  38  may have at least one flat section  66 , which faces radially outwards and in which the outer diameter of the collar  38  is reduced. There may be two or more such flat sections  66  along the circumferential direction  67 . The flat sections  66  may be arranged at diametrically opposed locations with respect to the longitudinal axis  32 . The at least one flat section  66  facilitates handling of the cable lug  1 . 
     Another embodiment of the cable lug  1  is shown in  FIGS. 5 and 6 . Here, the collar  38  is a separate part which is fixed or fastened onto the remainder of the cable lug  1 . In the embodiment of  FIGS. 5 and 6 , the collar  38  is a ring. As shown in  FIG. 6 , the cable lug  1  in particular the main body  27  may comprise a circumferential groove  68  in which the collar  38  may be received. The groove  68  may be located in the cylindrical section  44 , in particular at an end of the cylindrical section  44  which is located towards the appliance-side end section  30 . This configuration allows for a greater variability in the materials used for the collar  38  on one hand and the remainder of the cable lug  1  on the other. For example, the collar  38  may be made of a resin or plastic material, whereas the remainder of the cable lug  1  may be made from an electrical conductor such as copper, aluminum or an alloy containing at least one of copper and aluminum.