Abstract:
The invention refers to an electrical connector, in particular for connecting a receptacle (squib) to an electrical control unit for restraint systems in motor vehicles.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention refers to an electrical connector, in particular for connecting a receptacle (squib) to an electrical control unit for restraint systems in motor vehicles, for example air bags. 
     2. Description of Related Art 
     Such a connector is known from DE 295 21 491 U1. It comprises a housing for receiving electrical cables as well as contact springs connected thereto, the contact springs serving for receiving contact pins of the associated receptacle. Furthermore, catching means for securing the housing to the receptacle as well as a locking member are provided. The locking member serves for securing the catching means of the housing and the receptacle against an accidental detachment. The locking member is attached to the housing via flexible tongues and, after the tongues having been bent, is guided through a corresponding opening of the housing into the locking position. 
     In principle, the connector mentioned above has proved its worth; but because of the extremely small structure of the connector and the flexible tongues along which the locking member is guided, mounting of the locking member requires an appropriate experience, especially if it is to be mounted with one hand only. 
     This is true especially if the plugging part extends perpendicularly to a base body of the housing, as in DE 295 21 491 U1, and not coaxially with that, as is known from DE 195 13 358 C1. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a connector of the type mentioned above, the plugging part of which may be mounted easily to a plugging part of an associated receptacle, including the associated secondary locking by means of the said locking member. 
     The basic idea is not to hinge the locking member to the base body of the housing via flexible tongues but to guide it along the base body of the housing in a defined manner, that is between a condition in which the locking member is “open” (condition of delivery) and a condition in which the locking member serves its function as a secondary locking (that is in the condition of contact of the housing of the connector with the associated receptacle). 
     That definite guidance can be obtained with the aid of a locking member having an L-like shape. Here, a first portion of the locking member especially serves for the guidance on the base body of the housing, whereas a second portion projecting perpendicularly therefrom serves for the secondary locking function. 
     Accordingly, the invention in its most general embodiment refers to an electrical connector, in particular for connecting a receptacle to an electrical control unit for restraint systems in motor vehicles, having the following features: 
     a housing having a base body and a plugging part projecting perpendicularly from the base body and facing the receptacle, 
     contact springs are arranged in the plugging part of the housing, 
     first catching means are formed beside the plugging part for catching corresponding second catching means of the receptacle having contact pins, 
     an L-shaped locking member for securing the catching means of the housing and the receptacle, 
     a first portion of the locking member being U-shaped with legs extending in parallel and the legs as well as the base body of the housing having corresponding guiding means for guiding the first portion of the locking member in a longitudinal direction of the base body of the housing, and 
     a second portion of the locking member being U-shaped as well, the parallel legs of which secure the catching means of the housing and the receptacle against an accidental detachment, after the first portion having been moved in the longitudinal direction of the base body of the housing and the legs having been guided through corresponding openings in the base body of the housing. 
     For example, the guiding means may be formed by corresponding grooves and pegs (pins) in or on the legs of the first portion of the locking member or in or on side faces of the base body of the housing, as is described by claims  2  and  3 . 
     According to claim  2 , guidance of the locking member in a defined manner along the base body of the housing is effected along grooves on the housing, the pegs on the first portion of the locking member being guided along those grooves. 
     The grooves may extend from the upper surface of the base body of the housing into the base body. Because of the said small size of such connectors, for reasons of space it presents itself to form the grooves in the side faces of the base body so that the legs of the first portion of the locking member reach laterally beyond the base body. 
     The embodiment according to claim  3  is different from the configuration according to claim  2  by inversion of the guiding means. Correspondingly, that is also true for alternative configurations of the further embodiments described below and results in the following from subclaims  4 ,  6 ,  9 ,  10 ,  14  and  15 . 
     The movement of the locking member to the position of the secondary locking is facilitated by the grooves in the base body of the housing having an arcuate shape and extending towards the plugging part, at least at their end adjacent the plugging part. A specific arcuate guideway for the locking member is created thereby in order to guide it to the locking position by turning. 
     Here, the grooves may have a involute-like shape. 
     As shown in the description of the figures below, it is also possible to provide several grooves in the region of each leg of the first portion of the locking member and to form the legs having several pegs, correspondingly. In turning the locking member a definitely given guideway is obtained thereby. 
     In order to prevent the pegs sliding accidentally out of the grooves, an embodiment provides to arrange at least one end of the grooves at a distance from the free end of the base body of the housing and preferably at a distance from the end of the base body opposite the plugging part. Without problems, the other end of the groove may be “open”, because the movement of the locking member is limited by the connecting leg between the parallel legs of the first portion, when it hits the housing body. 
     According to an embodiment the grooves are provided with at least one elevation along their basis. 
     If this elevation is disposed at a distance from the “closed” end of the grooves, for example, the connector may be premounted at the factory (condition of delivery) in such a manner that the associated pins close to the end of the locking member are situated in the region between the elevations and the “closed” ends of the groove and thus prevent that the locking member “slips” to the locking position. However, the elevations have such a low height that in the final assembly (connection to the associated receptacle) a fitter may move the pins past the elevations with an appropriate pressure onto the locking member and guide them along the further groove portions to the secondary locking position. Second elevations at the opposite end of each guideway for the pins correspondingly serve for securing the locking member in its plugged-in position, as soon as the pins have been guided over those second elevations towards the plugging part. 
     A development of the said embodiments provides to dispose at least three pegs on each leg of the first portion of the locking member, one peg being guided on an arcuately shaped surface portion of the first portion, respectively. Accordingly, that peg does not slide along said grooves but slides virtually as a counterbearing on a corresponding surface portion of the base body of the housing. In that region as well, two or more of the said elevations may be disposed. 
     As known from DE 295 21 491 U1, the connecting leg extending between the legs of the second portion of the locking member may be split in the longitudinal direction. Correspondingly, two openings are to be provided in the housing, through which the legs may be guided. 
     In the configuration according to the invention, the second portion of the locking member may also be used to remove a shorting bar in the region of the contact pins of the receptacle, when the locking member has reached its maximum locking position. The corresponding structural configuration is known from DE 295 21 491 U1. 
     Especially for that application but also generally, the grooves in the base body of the housing may be formed at their end facing the plugging part in such a manner that the second portion of the locking member extends substantially in parallel with the plugging part, at least at the end of its guideway towards the receptacle. By this means, the secondary locking on the one hand and the removal of the shorting bar on the other hand is optimized. 
     Further characteristics of the invention follow from the features of the subclaims as well as the other application documents. 
     In the following, the invention is explained in more detail with an embodiment. Here, the figures show—each in schematic representation: 
    
    
     BRIEF DESCRIPTION OF THE FIGURES OF DRAWINGS 
     FIG. 1 a perspective view of a housing of a connector, 
     FIG. 2 a perspective view of an associated locking member, 
     FIG. 3 a schematic diagram showing the relative movement of the locking member with respect to the housing of the connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, the reference number  10  indicates a housing of a connector according to the invention. The housing  10  comprises a base body  12  of the housing and a plugging part  14  projecting prependicularly therefrom in a downward direction, in which contact springs (not illustrated) are disposed in the usual manner. 
     The base body  12  has substantially the shape of a right parallelepiped with side faces  12 . 1 ,  12 . 2 . 
     On each of the side faces  12 . 1 ,  12 . 2  a first groove  16  extends substantially in parallel with the basis  12 . 3  of the base body  12  at a distance from the right end in FIG.  1 . 
     Towards the plugging part  14 , a second groove  18  adjoins the groove  16 , extending from a first end (above the groove  16 ) arcuately to the basis  12 . 3  of the base body  12 . 
     In parallel with the extension of the groove  18  the base body  12  is former with an arcuate surface portion  20  on both sides, another groove  22  being formed thereby, which extends substantially in parallel with the groove  18 . 
     In that region of the base body  12  the housing  10  is formed with openings ( 28   a  and  28   b ), the function of which will be described in more detail below. 
     As shown in FIG. 1, in the region of the groove  16  a cam  24  is disposed at a distance from the right end of the groove  16 , which rises outwardly from a basis of the groove  16  and has an arcuate surface. 
     In the region of the groove  22  too, an analogous cam  26  is disposed at a distance above the basis  12 . 3  on both sides of the base body  12 . 
     The grooves  16 ,  18 ,  22  described above serve for receiving and guiding a locking member  30 , as illustrated in FIG.  2 . 
     The locking member is L-shaped. A first portion  30 . 1  is U-shaped, as well as a second portion  30 . 2  extending perpendicularly thereto. 
     The first portion  30 . 1  comprises two legs  30 . 11 ,  30 . 12  extending in parallel with each other and a leg  30 . 13  connecting the legs  30 . 11 ,  30 . 12  in the region of the second portion  30 . 2 , which extends above the second portion  30 . 2 . 
     The distance between the legs  30 . 11 ,  30 . 12  is slightly larger than the width B of the base body  12 . 
     On the inside, three pegs  16   z,    18   z  and  22   z  project perpendicularly from each leg  30 . 11 ,  30 . 12 . The diameter of each peg  16   z,    18   z,    22   z  is slightly smaller than the width of the associated groove  16 ,  18  and  22 , respectively. 
     The second portion  30 . 2  has a U-shaped cross section as well, the connecting leg  30 . 23  being slit in the longitudinal direction and the parallel side legs  30 . 21 ,  30 . 22  extending in parallel with the legs  30 . 11 ,  30 . 12 . 
     In correspondence with the shape of the second portion  30 . 2  of the locking member  30 , each of the said through openings  28   a  and  28   b  in the housing  10  is L-shaped. 
     In premounting, the locking member  30  is placed upon the base body  12 , that is in such a manner that the pegs  16   z  are positioned in the grooves  16 , the pegs  18   z  are positioned in the grooves  18  and the pegs  22   z  are positioned in the grooves  22 , that is at the beginning in such a manner that the pegs  16   z  are situated behind the elevations  24  and before the corresponding end  16   e  of the groove  16 . 
     For the other pegs  18   z,    22   z  and the locking member  30 , a position with respect to the base body  12  results, in which the second portion  30 . 2  of the locking member  30  does not (yet) project downwardly beyond the base body  12 . 
     After the plugging part  14  of the housing  10  having been put onto an associated plugging part of a receptacle, the locking member is first pressed “forwardly”, the pegs  16   z,    18   z  and  22   z  passing along the associated grooves  16 ,  18 ,  22  (direction of arrow x) and occupying the intermediate position illustrated in FIG. 3, for example. Afterwards, the pegs  16   z,    18   z  and  22   z  cause the locking member  30  to descend (direction of arrow y) towards the plugging part  14  and are guided further along the associated grooves  16 ,  18 ,  22  until the connecting leg  30 . 13  hits the surface  12 . 4  of the base body  12 . Now, the locking member  30  has reached its end position (secondary locking position) and the second portion  30 . 2  has removed said shorting bar in the region of the contact pins of the receptacle. Securing the locking member  30  in that position is effected by the pegs  22   z  being now situated behind the elevations  26 . 
     At their end on the right hand in the figures) opposite the plugging part  14  the grooves  16 ,  18 ,  22  may extend again downwardly (towards the plugging part  14 ) in an arcuate manner to guide the locking member  30  to a position (unlocking position) in which it is turned by at least 90° with respect to the upper surface  12 . 4  of the base body  12 . In that, the parallel legs  30 . 11 ,  30 . 12  are guided downwardly under the lower surface  12 . 3  of the base body  12  of the housing. At the same time the protecting part of the locking member  30  presses against a corresponding surface of the receptacle, the plugging part  14  being released from the position of contact with the receptacle thereby.