Patent Publication Number: US-9853366-B2

Title: Crimp contact with improved contacting and crimp connection

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of the filing date under 35 U.S.C. §119(a)-(d) of German Patent Application No. 102015224219.6, filed on Dec. 3, 2015. 
     FIELD OF THE INVENTION 
     The present invention relates to a crimp contact, and more particularly, to a crimp contact for crimping a conductor. 
     BACKGROUND 
     Crimp contacts having two crimp sections arranged on opposite sides of a crimp base are known in the art. An end of a conductor is positioned between the crimp sections and over the crimp base, and the crimp sections are crimped around the end of the conductor, for example, with crimping pliers or a crimping device. The conductor is thus connected both mechanically and electrically to the crimp contact. 
     Applications of crimp contacts in the mobile field, such as in automobile construction, require weight savings which are made possible by using, for example, aluminum conductor wires. Aluminum, however, forms insulative aluminum oxide from contact with ambient air, and consequently, electrically contacting an aluminum wire is difficult. It is therefore necessary to pierce through the aluminum oxide layer when electrically contacting an aluminum wire for the first time and advantageous to protect the aluminum wire from environmental influences in the case of further use. 
     Known crimp contacts generally consist of copper, and since aluminum and copper have different standard potentials, it is necessary to impede the ingress of any electrically conductive liquids; even liquids with the slightest impurities. By impeding ingress, it can be ensured that the aluminum does not electrochemically decompose due to the difference in electrical potential. In addition, through such a protection of the aluminum wires, hermetic sealing from ambient air may likewise be possible, which impedes a (renewed) oxidation of the aluminum. 
     In the prior art, such protection for the aluminum is addressed through self-protecting crimp connections. These known crimp connections are formed by crimp contacts having an insulation crimp, a conductor crimp, and wings or front protection lugs, wherein, in the crimping process, the wings or front protection lugs are crimped such that they block the access to the crimp sleeve. In addition, a self-protecting crimp has sealing agent repositories through which, during crimping, a sealing agent is made available which fills gaps still remaining in the crimped front protection crimp, in the crimped conductor crimp (i.e. between the conductor crimp and the aluminum conductor) and in the insulation crimp (i.e. between the insulation of the aluminum conductor and the insulation crimp) and thus prevents ingress of electrically conductive and/or corrosive liquids along with ambient air. 
     In the crimping process, the wings are curved in the direction of the receptacle of the conductor so that the wings which are opposite one another touch over an axis of symmetry of the crimp contact which extends in a longitudinal direction and come closer to the crimp base. Since the aluminum oxide layer is formed at all outer surfaces of the aluminum conductor prior to crimping, piercing through this aluminum oxide layer is accomplished during crimping through mechanical contact with the crimp contact; through serrations or indentations formed on the crimp contact 
     Single strands of the aluminum conductor situated on the inside of the conductor are, however, sometimes not sufficiently mechanically stressed during crimping in order to pierce through the aluminum oxide layer. These single strands situated on the inside are no longer available for the conduction of electrical current due to the aluminum oxide layer formed around them, and the resistance of the aluminum conductor used is increased. 
     A plug connector  2  according to the prior art comprising a crimp contact  1 , a contact member  5  extending in a longitudinal direction  7 , and a bearing strip  11  is shown in  FIGS. 1-4 . 
     The crimp contact  1  comprises two wings  13  and two crimp sections  15 , the crimp sections  15  comprising an insulation crimp  17 , a conductor crimp  19  and a front protection crimp  21 . The insulation crimp  17 , conductor crimp  19 , and front protection crimp  21  each extend from one crimp section  15  via a crimp base  23  to a crimp section  15  situated opposite, so that a continuous sleeve, the crimp sleeve  3 , is formed. The crimp sleeve  3  encloses a receptacle  24  in which a conductor  43  (not shown) can be received. The crimp sleeve  3  is linked to a bearing strip  11  via a linking bar  9 . The linking bar  9 , the bearing strip  11 , and the contact member  5  are shown purely by way of example. Serrations  25 , or indentations, are formed in the conductor crimp  19 , and a sealing agent repository  27  is formed in the front protection crimp  21 . 
     The crimp contact  1  is shown in a pre-crimped state  35  in  FIG. 2 . The front protection crimp  21  is integrally formed with the conductor crimp  19 , wherein, in the depiction shown in  FIG. 2 , the wing  13  separates both crimp regions  19 ,  21  from one another. On an underside  29  of the crimp contact  1 , a step  31  can be seen which distinguishes a transition region  33  between the conductor crimp  19  and the insulation crimp  17 . The receptacle  24  for the conductor  43  extends over the conductor crimp  19  and the insulation crimp  17 . The conductor insulation (not shown) of a conductor  43  (not shown) can be received in the insulation crimp  17 . 
     The crimp contact is shown in a crimped state  37  in  FIGS. 3 and 4 . In  FIG. 4 , in the crimped state  37 , the crimp base  23 , the crimp sections  15  and the wings  13  are shown, sectioned through the front protection crimp  21  of the crimp contact  1 . Since no conductor  43  is disposed in the area of the front protection crimp  21 , the crimp sections  15  and the wings  13  are rolled together such that they seal the crimp interior  41 . Gaps  51  may remain when the front protection crimp  21  and the wings  13  are crimped. 
     As shown in  FIG. 3 , sectioned through the conductor crimp  19  in the crimped state  37 , the crimp sections  15  extend from the crimp base  23  substantially perpendicular in a z-direction, and are curved towards one another, abutting in a striking region  39 . The crimp base  23  and the crimp sections  15  enclose a crimp interior  41  in which is situated the conductor  43 . In the embodiment shown in  FIG. 3 , the conductor  43  comprises twenty-three single strands  45 . The crimp interior  41  is formed by the receptacle  24  during crimping. 
     If such a crimp contact  1  is used to electrically contact an aluminum conductor  43 , then on the aluminum&#39;s surfaces exposed to the outer air there is situated an electrically isolating layer of aluminum oxide, with the layer of aluminum oxide having to be pierced through in order to electrically contact the single strand  45  located under the layer of aluminum oxide. A disadvantage of a crimp connection  4  of the prior art becomes clear from  FIG. 3 . Inner strands  45   a  are only in mechanical and electrical contact with other single strands  45 , but not with the crimp sections  15  or the crimp base  23 . The inner strands  45   a  are not subjected to any sufficiently great mechanical contacting, meaning that the layer of aluminum oxide on the inner strands  45   a  cannot be pierced through. Electrical conduction via the inner strands  45   a  is thus impaired and conductivity of the aluminum conductor  43  is lowered. 
     SUMMARY 
     An object of the invention, among others, is to provide a crimp contact which shields the exposed end of an aluminum conductor while directly contacting single strands in the interior of the aluminum conductor. The disclosed crimp contact has a receptacle extending in a longitudinal direction up to a receptacle end, a crimp section extending along the receptacle and beyond the receptacle end to a front end, and a wing extending from the crimp section between the receptacle end and the front end transversely to the longitudinal direction, the wing having a conductor displacing member overlapping the receptacle in the longitudinal direction. The receptacle receives a conductor in the longitudinal direction. The crimp section encloses the conductor subsequent to crimping. 
    
    
     
       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 perspective view of a crimp contact according to the prior art; 
         FIG. 2  is a side view of the crimp contact of  FIG. 1 ; 
         FIG. 3  is a sectional view of the crimp contact taken along line A-A of  FIG. 2 ; 
         FIG. 4  is a sectional view of the crimp contact taken along line B-B of  FIG. 2 ; 
         FIG. 5  is a side view of a crimp contact according to the invention; 
         FIG. 6  is a sectional view of the crimp contact taken along line C-C of  FIG. 5 ; 
         FIG. 7  is a side view of another crimp contact according to the invention; 
         FIG. 8  is a sectional view of the crimp contact taken along line C-C of  FIG. 7 ; 
         FIG. 9  is a top view of another crimp contact according to the invention in a stamped-out state; 
         FIG. 10  is a top view of another crimp contact according to the invention in a stamped-out state; 
         FIG. 11  is a top view of another crimp contact according to the invention in a stamped-out state; 
         FIG. 12  is a top view of another crimp contact according to the invention in a stamped-out state; and 
         FIG. 13  is a top view of another crimp contact according to the invention in a stamped-out state. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENT(S) 
     Embodiments of the present invention will be described hereinafter in detail with reference to the attached drawings, wherein like reference numerals refer to the like elements. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that the disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. 
     A crimp contact  1 ′ according to the invention is shown in  FIG. 5 . The crimp contact  1 ′ has a conductor displacing member  55  formed as a displacing barb  57 . The displacing barb  57  extends in a longitudinal direction  7  away from wing  13  in a direction toward the conductor crimp  19 . The wing  13  shown in  FIG. 5  has a width bF and is tapered such that a base  59  of the wing  13  is wider than an end  61  of the wing  13 . 
     In the shown embodiment, the displacing barb  57  is approximately parallel to the crimp base  23 , is formed substantially rectangularly, and has a length lv. The displacing barb  57  may alternatively taper in the longitudinal direction  7 . The displacing barb  57  may be substantially triangular, being rounded at both its tip and the opposite end connected to the wing  13 . 
     The crimp contact  1 ′ according to the invention is shown in a crimped state  37  in  FIG. 6 . The crimp base  23 , the crimp sections  15  and the two displacing barbs  57  provided at the wings  13  are shown in  FIG. 6  as sectioned through the conductor crimp  19 . Due to the arrangement of the displacing barbs  57  at the end  61  of the wings  13 , both displacing barbs  57 , seen in the z-direction, are arranged substantially in the center of the crimp interior  41  after crimping. Alongside the strands  45  which touch the crimp base  23  or the crimp sections  15 , the displacing barbs  67  electrically contact the inner strands  45   a  of the conductor  43 . An individual displacing barb  57  arranged at the end  61  of one wing  13  may be used if the strands  45  have a diameter dE which does not exceed approximately 25% of a height  63  of the crimp interior  41 . 
     In the embodiment shown in  FIG. 6 , the number of strands  45  shown is merely exemplary, and the number of strands  45  can vary. Furthermore, the extent of extension of the crimp sections  15  into the crimp interior  41  shown in  FIG. 6  is purely by way of example and may vary among various applications. 
     In the front protection crimp  21  of the crimp contact  1 ′, as similarly shown in  FIG. 4 , a sealing agent  53  is used. The sealing agent  53  may be made available by sealing agent repositories  27 , filling the gaps  51  during crimping so that no corrosive liquids and/or ambient air can get into the crimp interior  41 . The sealing agent  53  may also be provided in the receptacle  24 , between the front end  49  and a receptacle end  47  of the crimp contact  1 ′, or in the region of a conductor crimp  19 . The sealing agent  53  may be a grease. The sealing agent  53  may thus be disposed in the insulation crimp  17 , at the crimp sections  15 , and at the wing  13  so that neither electrically conductive or corrosive liquids nor ambient air can penetrate into a crimp interior  41 . 
     A crimp contact  1 ′ according to another embodiment of the invention is shown in  FIGS. 7 and 8 . The crimp contact  1 ′ is shown in a pre-crimped state  35  in  FIG. 7 . The crimp contact  1 ′ has three displacing barbs  57  which are distributed in the z-direction along the wings  13 , extending substantially parallel to the crimp base  23  and protruding from the wings  13  in a longitudinal direction  7 . In the shown embodiment, the displacing barbs  57  are arranged equidistant to one another along the wings  13 . The distance of the displacing barbs  57  to one another and the distance relative to the crimp sections  15  can vary depending on the configuration of the crimp contact  1 . In all embodiments having a plurality of displacing barbs  57 , the displacing barbs  57  can be formed identically or with various shapes. 
     The crimp connection  4  of the crimp contact  1 ′ in a crimped stated  37  is shown in  FIG. 8 . The displacing barbs  57 , at various positions in the crimp interior  41 , create mechanical and electrical contact with the inner strands  45   a . In an embodiment, all strands  45  of the conductor  43  are mechanically and electrically contacted by the crimp base  23 , the crimp sections  15  or the displacing barbs  57 . The plurality of displacing barbs  57  may be used when the strands  45  have a diameter dE smaller than approximately 25% of the height  63  of the crimp interior  41 . 
     In  FIGS. 9-13 , a crimp contact  1 ′ according to the invention is shown in various embodiments in a stamped-out state  65 . The figures show a part of the linking bar  9 , the front protection crimp  21 , the conductor crimp  19 , the transition region  33  and a portion of the insulation crimps  17 . The crimp base  23  is indicated by a dashed line. A side of the crimp contact  1 ′ visible in the figures is a conductor-receiving side  66 . The conductor-receiving side  66  points, in the pre-crimped state  35 , into the receptacle  24  and, in the crimped state  37 , into the crimp interior  41 . The wings  13  and the variously formed conductor displacing members  55  are also shown. The crimp sections  15  are in each case situated to the left and right respectively of the crimp base  23  and extend from the insulation crimp  17  up to the front protection crimp  21 . 
     Serrations  25  and end markings  67  situated in the conductor crimp  19  of each crimp contact  1 ′ in  FIGS. 9-13  are also shown. The end markings  67  are two-part in the shown embodiments of the crimp contact, but in other embodiments can be formed as one part and extend from the left crimp section  15  over the crimp base  23  to the right crimp section  15 . The end markings  67  are surface structures which are oriented substantially perpendicular to the longitudinal direction  7  and which can, for example, be embossed. The end markings  67  indicate to the user up to where the stripped end of the conductor  43  must be pushed, counter to the longitudinal direction  7 , into the crimp sleeve  3  which is created by bending the two crimp sections  15  up out of the plane of projection. The end markings  67  are thus situated between the front protection crimp  21  and the conductor crimp  19 . The end markings  67  may protrude from the crimp contact  1 ′ perpendicularly to the longitudinal direction  7  so that this region represents a mechanical stop point for that end of the aluminum conductor  43 . In such a configuration, the user can thus displace the aluminum conductor  43  to in the longitudinal direction  7  until the aluminum conductor  43  strikes the end markings  67  and thus signals to the user via a haptic feedback that the aluminum conductor  43  is correctly inserted into the crimp contact  1 ′. 
     The embodiment of the crimp contact  1 ′ shown in  FIG. 9  has, at the ends  61  of the wings  13 , conductor displacing members  55  formed as displacing barbs  57 . These displacing barbs  57  each directly adjoin the end  61  of the wing  13 , i.e. in contrast to the displacing barbs  57  shown in  FIG. 5  they are not at a distance from the end  61  of the wing  13 . 
     The embodiment of the crimp contact  1 ′ shown in  FIG. 10  has displacing barbs  57  each formed at the base  59  of a wing  13 . It can also be seen that the wings  13  have an incline  69  at the front end  49  of the crimp contact  1 ′. With the shown incline  69 , it can be ensured that the wing  13  is rolled up towards the base  59  starting with the end  61 . 
     The embodiment of the crimp contact  1 ′ shown in  FIG. 11  has symmetrical wings  13  and displacing barbs  57  arranged antisymmetrically on these wings  13 . The ends  61  of the wings  13  are in each case at a distance  1 F from a center axis  71  of the crimp contact  1 ′. A first displacing barb  57   a  is situated at the distance  73   a  from the center axis  71 , with a gap  75   a  being situated at the same distance  73   a  on the opposite wing  13 . A second gap  75   b  which is situated at a distance  73   b  from the center axis  71  adjoins the first displacing barb  57   a  at the left wing  13 . At the same distance  73   b  a second displacing barb  57   b  is situated on the right wing  13 . At a distance  73   c , a third displacing barb  57   c  is situated on the left wing  13  and a third gap  75   c  is situated on the right wing  13 . At a distance  73   d , there are situated a fourth gap  75   d  on the left wing  13  and a fourth displacing barb  57   d  on the right wing  13 . A fifth displacing barb  57   e  adjoins the fourth gap  45   d  of the left wing  13  at a distance of  73   e  relative to the center axis  71 . At the right wing  13 , adjoining the fourth displacing barb  57   d , a fifth gap  75   e  is arranged at a distance of  73   e  relative to the center axis  71 . The displacing barbs  57   a - 57   e  and the gaps  75   a - 75   e  are thus arranged antisymmetrically relative to the center axis  71 , the distances being measured relative to the center axis  71 . 
     In the embodiments of the crimp contact  1 ′ shown in  FIGS. 12 and 13 , the conductor displacing member  55  is present in each case in the form of a widened base  77  of the wing  13 . Counter to the longitudinal direction  7 , the wing  13 , at the height of the end markings  67 , directly adjoins in each case the widened bases  77 . The widened bases  77  shown in  FIGS. 12 and 13  in each case extend in a tapering manner from the crimp sections  15  up to the ends  61  of the wings  13 . 
     As shown in the embodiment of  FIG. 12 , the crimp contact  1 ′ has serrations  25  which extend from a widened base  77  to the opposite widened base  77 . The serrations  25  pierce through an oxide layer  79 . In this case, the serration  25   a  formed in the conductor crimp  19  in  FIG. 12  is the element for breaking through an oxide layer  79 , with which the oxide layers of the outwardly situated single strands  45  are pierced through, while the regions of the serrations  25   b  of the widened bases  77  are curved during crimping between the strands  45  and thus pierce the oxide layers of the inner strands  45   a . After the oxide layers  79  are pierced through, an electrical contact is created between the crimp contact  1  and the conductor  43  by the widened bases  77  located between the inner strands  45   a . The serrations  25  shown in  FIG. 12  are continuous in the embodiment shown, but may consist of several sections in other embodiments. 
     As shown in the embodiment of  FIG. 13 , the crimp contact  1 ′ also has widened bases  77  of the wings  13  as conductor displacing members  55 . In contrast to the configuration of the crimp contact  1 ′ shown in  FIG. 12 , the crimp contact  1 ′ shown in  FIG. 13  has no serrations  25  in the region of the widened bases  77 , but rather has bores  81  which are used as elements for piercing through an oxide layer  79 . The bores  81  may only partially extend into the crimp contact  1  or can be fully bored through it. It can also be seen that the bores  81  on the symmetrically arranged wings  13  are arranged antisymmetrically. The bores  81   a - 81   e  are positioned in increasing distance from the center axis  71 . The bores  81  and the gaps  75  thereof are consequently, like the displacing barbs  57  and gaps  75  of  FIG. 11 , arranged alternatingly and antisymetrically.