Patent Publication Number: US-7591691-B2

Title: Plug-in connector

Description:
PRIOR ART 
     The present invention relates to a plug-in connector according to the preamble of the independent claim. 
     DE 10 2005 024 336 A1 describes an electric plug-in connector that provides increased extraction or pull-out force for a line connected to the plug-in connector, which force is achieved by a secondary locking element. The secondary locking element is pushed into the locked position, transversely to the plug-in direction, after the contact elements have been mounted in a plug-in connector base element. In its locked position, the secondary locking element engages behind a locking shoulder arranged on each of the contact elements. 
     A plug-in connector comprising a secondary locking arrangement with strain relief has been described in DE 100 15 842 C1, where a contact element is retained by a spring in a primary locking recess in the mounted condition of the contact element. 
     With the contact elements mounted in the plug-in connector base element, a secondary locking element is pushed onto the plug-in connector base element transversely to the plug-in direction so that it comes to embrace the plug-in connector base element by both sides. Locking noses formed on both sides of the secondary element extend over the full width of the secondary locking element. In the mounted condition of the secondary locking element, the two locking noses engage behind the rear end of each of the contact elements, viewed in the plug-in direction, thereby securing the contact element from being pulled off the plug-in connector base element unintentionally. 
     DE 10 2005 033 696 A1 describes a contact element of a plug-in connector that comprises two contact springs arranged within a cuboid section of the contact element as well as two spring tongues arranged on the outer lateral surfaces of the cuboid section. The ends of the spring tongues serve as locating tongues that cause the contact element to snap into place as the contact element is pushed into an enclosing plastic housing not disclosed in more detail. 
     A contact element designed as a multipoint socket connector comprising a resilient retaining clip designed to engage behind a recess in a contact housing has become known from DE 28 08 671 A1. Once locked in place, the retaining clip used as locating element prevents the contact element from being pulled off or pushed out of the contact housing against the plug-in direction. 
     The contact element comprises a further resilient retaining clip that urges the connection line against the inner wall of the plug housing in the area of the insulation. 
     EP 141091 A2 describes a contact element with a penetration terminal for miniaturized electric plugs, having a contact area and a wire clamping area. A penetration terminal in the form of a lug with two protuberances on its free upper edge is bent off from a basic web in the wire clamping area. The penetration terminal exhibits a duplex design consisting of two penetration lugs placed one against the other. A forward edge and a rear edge of the penetration lug are equipped with barb-like teeth that serve to anchor the penetration terminal in a slot—not described in more detail—of a housing not shown. 
     Now, it is the object of the present invention to provide a plug-in connector with high pull-out force. 
     That object is achieved by the features defined in the independent claim. 
     DISCLOSURE OF THE INVENTION 
     The plug-in connector according to the invention proceeds from at least one contact chamber provided in a plug housing for receiving a contact element that provides at least one abutment for a locating element arranged on the contact element. The locating element is designed as an inelastic locating hook. The side wall of the contact chamber is resilient, at least in the area before the abutment. Further, a recess is provided in the plug housing at least adjacent the resilient area of the side wall. 
     Compared with the solution known from the prior art, the plug-in connector according to the invention provides considerably increased extraction force or pull-out force that tends to prevent the contact element from being extracted or pulled out of the plug housing unintentionally. 
     In making the plug-in connection according to the invention, the contact element can be pushed into the plug housing at comparatively low force. The force-saving mounting process reduces the loading on the mounting unit thereby increasing its service life. 
     The high extraction force and the simple mounting process are the result of a simple structure of the plug-in connector which does not give rise to higher costs, compared with the designs according to the prior art. 
     This results in considerable cost savings, especially in series production of the plug-in connector according to the invention. 
     The plug-in connector according to the invention meets high safety demands, as specified for example for plug-in connections in the automobile industry. 
     The plug-in connector according to the invention is suited for making high-current plug-in connections having increased safety demands with respect to the pull-out force. The plug-in connector according to the invention is especially suited for realizing multipole plug-in connectors with a small number of poles, which still provide the high pull-out force. 
     Advantageous further developments and embodiments of the plug-in connector according to the invention are obvious from dependent claims. 
     One embodiment provides that both side walls are resilient, at least in the area before the abutments, and that recesses are provided in the plug housing at least adjacent the resilient area of both side walls. This embodiment leads to a symmetric arrangement, relative to one contact element. That arrangement is suited especially for producing multipole plug-in connectors where a recess is provided in the plug housing between each pair of neighboring contact chambers. 
     According to one embodiment, locating hooks are provided on both sides of the contact element. With the aid of that feature the pull-out force maximally achievable per contact element of the plug-in connection is obtained. 
     Another embodiment provides that the side wall comprises at least one tapered portion. In some cases, two tapered portions are provided. It may be provided especially that the at least one tapered portion is provided at the lower and/or the upper end of the side wall. The at least one tapered portion of the side wall contributes toward giving the side wall the desired resilient properties. 
     According to one embodiment, the edge length of the locating area of the locating hook is determined depending on the predefined pull-out force and/or mounting force. Another embodiment provides that the maximum projection length of the locating hook is determined depending on the predefined pull-out force and/or mounting force. Still another embodiment provides that the angle of inclination of the projection of the hook is determined depending on the predefined pull-out force and/or mounting force. 
     With the aid of these features it is possible to vary the pull-out force and/or the mounting force within a wide range although it must be considered in this connection that in the presence of firmly defined resilience properties of the side wall the pull-out force and the mounting force will increase similarly. 
     Certain embodiments of the invention are illustrated in the drawing and will be described hereafter in more detail. 
    
    
     
       In the drawing: 
         FIG. 1  shows a perspective view of a plug-in connector according to the invention, in mounted condition; 
         FIG. 2  shows a perspective view of a contact element with a locating hook; 
         FIG. 3  shows a sectioned perspective view of a plug-in connector according to the invention in mounted condition, viewed in the direction of an abutment; and 
         FIG. 4  shows a sectioned perspective view of a plug-in connector according to the invention in mounted condition, viewed from a different perspective. 
     
    
    
       FIG. 1  shows a perspective view of a plug-in connector  10  according to the invention, with components fitted, where at least one contact element  11  is arranged in a plug housing  12 . The plug-in connector  10  is further shown in the condition in which it is fitted in a corresponding plug-in connector  13  which latter comprises a corresponding plug housing  14 . 
     During the fitting operation, the contact element  11  is pushed  20  through a contact element opening  21  of the plug housing  12  in the fitting direction. For fitting it is likewise possible to push the plug housing  12  onto the at least one contact element  11 . This is why the fitting direction  20  is indicated by two-sided arrows in  FIG. 1 . In the example illustrated in  FIG. 1 , the fitting direction  20  further corresponds to the plug-in direction of the plug-in connection that comprises the two plug-in connectors  10 ,  13 . 
     The contact element  11  comprises a solder terminal  22 , implemented preferably as SMD solder terminal  22 . The solder terminal  22  can be soldered to a board not illustrated in  FIG. 1 , on which the plug housing  12  of the plug-in connector  10  can likewise be fixed by soldering or screwing via a mounting element  23 . 
     The contact element  11  is arranged in the plug housing  12  in a contact chamber not visible in  FIG. 1 , the chamber being laterally delimited by a first and a second side wall  30 ,  31 . The side walls  30 ,  31  are each provided with end faces  32 ,  33  in the area of the contact element opening  21 . 
     The first side wall  30  is arranged adjacent a first recess  34  provided in the plug housing  12 , while the second side wall  31  is arranged adjacent a second recess  35 . 
     The at least one side wall  30 ,  31  is resilient. The resilient property of the side wall  30 ,  31  is influenced selectively by at least one tapered portion  36 ,  37 . The at least one tapered portion preferably is provided at the lower/upper end of the side wall  30 ,  31 . Preferably, tapered portions are provided at both the lower and the upper ends of the side wall  30 ,  31  for allowing the resilient properties of the at least one side wall  30 ,  31  to be made symmetrical. 
     If two side walls  30 ,  31  adjoin one recess  34 ,  35  and if tapered portions  36 ,  37  are provided on both the lower and the upper ends of the side walls  30 ,  31 , then the recesses  34 ,  35  have a bone-like cross-section. 
       FIG. 2  shows a perspective view of the contact element  11 , where parts identical to those of  FIG. 1  are indicated by the same reference numerals as in  FIG. 1 . 
     A locating hook  41 , which preferably is formed from the contact element  11  by punching, is provided on at least one lateral surface  40  of the contact element  11 . Punching allows the locating hook  41  to be produced at especially low cost. 
     The angle of inclination  42 , the edge length  43  and the projection length  44  can be determined during the operation of making the locating hook  41 . The edge length  43  and the projection  44  define the locating area  45  of the locating hook  41  that coacts with a locating area of an abutment illustrated in  FIG. 3 , which will be described hereafter. 
     In the embodiment illustrated in  FIG. 2 , the contact element  11  is equipped with a multipoint pin contact  46 . 
       FIG. 3  shows a perspective cross-section through the plug-in connector  10  according to the invention with components fitted and in the plugged-in condition. Those parts of  FIG. 3  that correspond to the parts illustrated in the preceding Figures are indicated by the same reference numerals. 
     In the mounted condition, the at least one contact element  11  is arranged in a contact chamber  50 . The locating hook  41  has passed the end face  32  of the first side wall  30  and has snapped into place. In the snapped-in condition, the locating area  45  of the locating hook  41  rests on the locating area of an abutment  51 ,  52 . 
     For purposes of the illustrated embodiment it has been assumed that the projection length  44  of the locating hook  41  corresponds to the locating area of the abutment  51 ,  52  that matches the projection  44 . Further, it has been assumed for purposes of the illustrated embodiment that a locating hook  41  is provided on the contact element  11  only on one lateral surface  40 . 
     The locating hook  41  is inelastic. To be inelastic means that the locating hook  41  has no or only slight resilient properties. During the mounting operation, the locating hook  41  must be capable at least of applying the mounting force necessary to push the end face  32 ,  33  of the at least one side wall  30 ,  31 , and the at least one side wall  30 ,  31  far enough to the outside and into the neighboring recess  34 ,  35  as to permit the locating hook  41  to be introduced through the contact element  41  and to be pushed forward in the mounting direction  30  a sufficient distance to permit the locating area  45  of the locating hook  41  to reach the corresponding locating area of the abutment  51 ,  52 . 
     When the rear end of the locating area of the locating hook  41  passes the corresponding locating area of the abutment  51 ,  52 , the locating hook  41  will snap into the abutment  51 ,  52 . 
     As has been mentioned before, the term “before the abutment” relates to the mounting direction  20  and corresponds to that area of the side wall  30 ,  31  along which the locating hook  41  slides during the mounting operation, thereby bending the side wall  30 ,  31  in outward direction before the locating hook  41  reaches the abutment  51 ,  52 . According to one embodiment, a larger portion or even the entire side wall  30 ,  31  may be made resilient. 
       FIG. 3  shows a plug-in connector  10  in the plugged-in condition with the matching plug-in connector  13 . The multipoint pin contact  46  of the contact element  11  coacts with a corresponding multipoint slot contact  60  of the corresponding contact element  61 . 
       FIG. 4  shows a sectioned perspective view of a plug-in connector  10  according to the invention, in mounted condition and in plugged-in condition, viewed from a different perspective where the end face  32 ,  33  of the at least one side wall  30 ,  31  is freely visible.