Abstract:
The present invention relates to a connector assembly for airbag restraint systems. The connector assembly comprises a connector housing and secondary locking means assigned to the connector housing. The secondary locking means is arranged movable relative to the connector housing and can be moved from an open position to a locked position. Further the secondary locking means comprises two separate locking members wherein each of the two separate locking members is configured to be independently movable.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 U.S.C. §119(a) of European Patent Application No. 14176820.0, filed in the European Patent Office on Jul. 11, 2014, the entire disclosure of which is hereby incorporated by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a connector assembly, in particular for airbag restraint systems. The connector assembly comprises a connector housing and secondary locking means. The secondary locking means is assigned to the connector housing so that it is movable relative to the connector housing from an open position to a locked position. 
     BACKGROUND OF THE INVENTION 
     In many applications, the safe coupling of connectors is of high importance. For example, in the case of car safety systems, as e.g. airbag systems in passenger cars, the connectors used for the connection of an airbag to its ignition base have to be provided with reliable safety systems. To ensure that the connectors cannot become loose unintentionally, secondary locking means are used in addition to the primary locking means to guarantee a safe mechanical coupling. 
     An example of a connector with a secondary locking means is described in WO 97/41623 A1. This document discloses a connector which can be mated with a corresponding counter-connector being part of an airbag ignition mechanism. In assembled condition, (i.e. the connector is mated with the corresponding counter-connector), the connector is fixed to the counter-connector by means of flexible latching arms. During mating of the connectors, these arms are deflected and snap back into corresponding latching clearances of the counter-connector, when fully mated. For securing the mechanical coupling of the connectors, WO&#39;623 suggests a secondary locking means that comprises locking arms that can be inserted into the mated connector assembly. Once the locking arms are inserted, they inhibit bending of the latching arms out of the corresponding latching clearances. Thus, the mechanical coupling of the connectors is secured. 
     A further development of a secondary locking means is disclosed in the patent application DE 100 05 858 A1. This document discloses a connector with a secondary locking device and a safety spring element, which serves to hold the secondary locking means in a position, in which the secondary locking means is mounted to the connector housing so that it does not hinder mating or un-mating of the connector with a corresponding counter-connector. 
     In patent application WO 2014/072081 A1, a connector assembly is disclosed that comprises a secondary locking means and a spring. The secondary locking means and the spring are assigned to a connector housing. Hereby the secondary locking means is movable between a first and a second position. When placed in its second position, it serves to secure the mating of the connector housing to a corresponding counter-connector. During mating, the spring is biased to cause the secondary lock to move automatically into a locked position when the connector assembly is fully mated with is corresponding counter-connector, without need for an operator to push the secondary locking means into the locked position. 
     The connector assemblies described above have in common that a partial mating of the connector and the corresponding counter-connector is possible, in which case the secondary locking means do not function satisfactorily. 
     If the connector is only partially mated, it might occur that the connector assembly electrically functions correctly, since the electrical contacts of the connector and the corresponding counter-connector are connected (i.e. current conduction is possible), but the mechanical connection is not according to the desired specification. In a highly safety relevant connector assembly, for example in airbag restraint systems, often detecting devices are integrated that are able to detect a correct mating of the counter-connectors based on electrical circuits that are opened respectively closed during the mating of the connector. If the connector and the corresponding counter-connector are partially mated, these detecting devices may report untruly a correct mating of the connectors. Further, with the prior art secondary locking means it was often possible to move the same in the locked position, thereby indicating to an operator, that the mating is complete. However, in case of only a partial mating, the prior art secondary locking means often fail to provide the desired secondary locking function. In the case of e.g. airbag restraint systems the electrically functional but mechanical disturbed connector might disengage due to vehicle vibration. 
     BRIEF SUMMARY OF THE INVENTION 
     The present application relates to a connector assembly, in particular for airbag restraint systems. The connector assembly comprises a connector housing and secondary locking means (i.e. a secondary lock). 
     The connector housing comprises at least one primary latching arm configured to latch with a corresponding counter-connector. The connector housing may comprise a plug-in portion and at least two primary latching arms that are arranged on opposite sides of the plug-in portion, whereby the plug-in portion enters the corresponding counter-connector at least partly upon mating. The latching arms of the plug-in portion are deflected during mating and snap back into corresponding latching grooves or recesses provided in the counter-connector, when mated. Thereby each latching arm can be deflected and mated individually. 
     The secondary locking means is assigned to the connector housing, and is arranged movable relative to the connector housing from an open position to a locked position. The secondary locking means may be guided in its movability by the connector housing, so that the trajectory from an open to a locked position of the secondary locking means is defined. The same applies for the movement of the secondary locking means form the locked in the open position. 
     After at least one of the latching arms is in its mated position, the secondary locking means can be moved in the mating direction, in accordance with the defined trajectory. The end point of said trajectory is defined as the locked position. 
     The secondary locking means comprises further blocking portions that are configured to block a release movement of the latching arms when the secondary locking means is in its locked position. These blocking portions of the secondary locking means may be arranged relative to the latching arms of the plug-in portion so that a deflection of the latching arms is made impossible or at least hindered. Thus, the latching arms cannot be released and the connector is secured by the latching arms and the blocking portions in the mated condition. 
     Advantageously, the secondary locking means of the invention comprises two separate locking members. The separate locking members are thereby two physical different parts. The two separate locking members may be formed symmetrically identical. However, any other suitable shaping of the separate locking members is possible. Further, each of the two separate locking members is assigned to one of the primary latching arms to block a release movement of the assigned latching arm. Thereby, each of the two separate locking members is configured to be independently moveable between the open position and the locked position along its own trajectory. Therefore, if the connector is unintentionally only partially mated, i.e. only one of the two latching arms is latched in its latching groove, the locking member assigned to the latched (i.e. mated) latching arm can be moved in its locked position, even if the locking member assigned to the not-latched latching arm cannot. 
     In this locked position, the single locking member blocks a release movement of the latched latching arm and the connector is sufficiently secured, even in such a partially mated condition. This secured, partially mated condition provides retention forces that are strong enough to avoid an unintentional disengagement of the connector. 
     According to one embodiment, the connector assembly is further provided with a spring, that is operationally connected to at least one of the locking members and possibly to both of the locking members, to bias the respective locking member into its locked position when the connector housing is fully mated with a corresponding counter-connector. Thus, the spring is configured to urge the locking members to move automatically into their locked position when the assigned latching arm of the connector housing is mated with is corresponding counter-connector without need for an operator to push the secondary locking member manually into the locked position. 
     The secondary locking members may each comprise at least one blocking portion, which is configured to block a release movement of the latching arm(s) when the secondary locking means is in the locked position. The blocking portion can for example be arranged on a dedicated element such as an actuating arm of the locking member or can be provided for example as part of other functional members of the locking member. This blocking portion may be arranged such that it blocks the latching arms of the connector housing in their respective positions, when the secondary locking means is in the locked position. Each locking members may further comprise at least one actuating arm each configured to latch to a corresponding counter-connector when mated and when the secondary locking means is in its locked position. Thereby, the locking member can be secured in the locked position. 
     In one embodiment, the connector assembly is further provided with a shortening element, which allows the monitoring of the mating process, respectively the monitoring of a correct mating between connector housing and corresponding counter-connector. The shortening element is an electrical contact element and configured to be actuated upon mating by coming into contact with a portion of the corresponding counter-connector. Thereby, the shortening element is disposed, to close or open an electrical circuit. The opening or closing of the electrical circuit allows a remote monitoring of the mating process. To this end, the shortening element may be provided such on the connector housing, that it is only disposed (thereby opening or closing the electrical circuit), upon fully and correct mating of counter-connector and connector housing. 
     Generally, the connector assembly of the present invention may also further comprise a corresponding counter-connector and the corresponding counter-connector may be an airbag squib socket and the connector housing accordingly may be an airbag squib connector housing. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
         FIGS. 1 and 2  show schematic illustrations of a connector housing comprising two separate locking members in accordance with the present invention from different views; 
         FIG. 3  shows a schematic illustration of the connector housing illustrated in  FIGS. 1 and 2 , whereby the cover of the connector housing is removed; 
         FIG. 4  shows a top view of the connector housing with removed cover; 
         FIG. 5  shows a side view of the connector housing in a partially mated and locked condition; 
         FIG. 6  shows an X-ray photo of the connector housing of  FIG. 5  in a partially mated and locked condition; 
         FIG. 7  shows a partially cut view illustrating the interior of the connector housing upon mating in the open position; and 
         FIG. 8  shows the same partial cut as  FIG. 7 , however, with the locking member  30   a  in its locked position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In one aspect, the present invention improves the state of the art by providing a connector assembly with an improved secondary locking mechanism. 
       FIG. 1  shows a perspective, three-dimensional view of a connector housing  10  in accordance with the invention. The connector housing  10  comprises a main body  12  and a cover  11  which is removably latched to the main body  12  by means of latch connections  15 . At the bottom side of the main body  12  a cylindrical plug-in portion  13  is provided. The skilled person will recognize that the plug-in portion  13  is configured to co-operate with typical airbag squib sockets and that the device shown is thus an airbag squib connector. On opposite sides of the plug-in portion  13 , two latching arms  20   a ,  20   b  are arranged. In other words, the two latching arms  20   a ,  20   b  are arranged symmetrically on opposite sides of the plug-in portion  13 . The latching arms  20   a ,  20   b  provide the primary locking of the connector. Indicated by the reference number  30 , a secondary locking means is arranged moveable inside of the main body  12  of the connector housing  10 . Secondary locking means  30  is shown in its locked position and consists of two distinct locking members  30   a  and  30   b . When coupled or mated to a corresponding counter-connector, the secondary locking means  30  will prevent an unintentional un-mating of the two connector parts, when in the position shown in  FIG. 1 . 
       FIG. 2  shows the same device from a different angle. Further, in  FIG. 2  a retainer  50  is shown for illustrative purposes. The skilled person will recognize that the retainer  50  is part of an airbag squib socket and thus forms part of the corresponding counter-connector. Also visible in the view of  FIG. 2  is the spring  40 , which biases the secondary locking means  30  into its locked position. The spring  40  is such arranged in the connector housing  10  that upon mating the spring  40  will automatically move the secondary locking means  30  in the locked position shown in for example  FIG. 2 . 
       FIG. 3  shows again the same arrangement as  FIG. 2  from a different perspective, however with the cover  11  removed to allow a view of the interior construction of the connector housing  10 . From  FIG. 3  one can see that cables  14  are mounted inside of the connector housing  10 . The cables  14  are partially covered by a ferrite element  16 , as it is well known to the skilled person. In the open view of  FIG. 3  one can see that the spring  40  is made from a single wire of spring steel. Further, each locking member  30   a ,  30   b  comprises an actuating arm  31   a ,  31   b  (only actuating arm  31   b  is visible in  FIG. 3  due to the perspective). 
     Spring  40  comprises in the embodiment shown two spring arms  41   a ,  41   b  that are operationally connected to the locking members  30   a  and  30   b . Further, as one can take from  FIG. 2 or 3 , the coils  42  are arranged, such that the winding axis of each coil  42  is in a plane perpendicular to the mating direction of the connector housing  10 . It is clear for the skilled person, that the shown spring  40  is only one example and that it is possible to use also other constructions without deviating from the core idea thereof. 
     Turning back to  FIG. 3 , one can see that the spring  40  is tensioned when the locking members  30   a ,  30   b  are in their open position. Upon mating, the spring  40  will automatically move the locking members  30   a ,  30   b  in the locked position. How this is achieved will be explained in more detail in the following with regard to  FIGS. 6 and 7 . 
     Turning back to  FIGS. 3 and 4 , one can see how the two spring arms  41   a ,  41   b  of spring  40  are operationally connected to the respective locking members  30   a ,  30   b  of the secondary locking means  30 . The position of secondary locking means  30  shown in  FIGS. 3 and 4  is the so called open position. In this position it is possible to fully mate the connector housing  10  with the corresponding counter-connector, since the secondary locking means  30 , i.e. the locking members  30   a ,  30   b  do not block the latching arms  20   a ,  20   b.    
     The spring  40  in accordance with the present invention comprises at least two spring arms  41   a ,  41   b  each actuating arm  31   a ,  31   b  being operationally connected to a respective one of the two locking members  30   a ,  30   b , for biasing the locking members  30   a ,  30   b  individually in their locked position. This can for example be achieved, by a direct contact of the spring arm  41   a ,  41   b  and the locking members  30   a ,  30   b , however, it could also be achieved indirectly by further elements which are being provided between the actuating arm  31   a ,  31   b  and the locking member  30   a ,  30   b . It is however important, that the actuating arm  31   a ,  31   b  actively pushes or moves the locking member  30   a ,  30   b  from the open position into the locked position upon mating of connector housing  10  and corresponding counter-connector. 
       FIG. 5  shows the connector housing  10  in a partially mated condition, which might occur, if only one side of the edge of the connector housing  10  is pushed down. As a result, the connector housing  10  is mated oblique into the corresponding counter-connector. Locking member  30   a  is still in its open position, whereas locking member  30   b  has been moved to its locked position. The retention force of a partially locked connector is greater than 78 newtons (N) and may be greater than 135N. The retention force is the force that is necessary to unmate the connector housing  10  and the corresponding counter-connector when pulled in mating direction. The retention force is measured according to the test method described in ISO 19702-2, §4.4. 
       FIG. 6  shows an X-ray photo of the partially mated connector. To facilitate the understanding, the latching arms  20   a ,  20   b  and the actuating arms  31   a ,  31   b  of the locking members  30   a ,  30   b  are retraced. As one can see on the right side of  FIG. 6 , latching arm  20   b  is latched to the latching groove  55  and actuating arm  31   b  of locking member  30   b  blocks the latching arm  20   b , since the locking member  30   b  is in its locked position. Latching arm  20   a  is not latched, i.e. only a partial mating of connector housing  10  and corresponding counter-connector occurs. Further, since the latching arm  20   a  is not latched, the locking member  30   a  with actuating arm  31   a  is still in its open position. Nevertheless, since the other locking member  30   b  is in its locked position, the connection is sufficiently secured. 
       FIG. 7  shows a partially cut view of the connector during the mating process. From the cut view, one can see how the plug-in portion  13  is partially inserted into the retainer  50 . In the position shown, a stop member  51  of retainer  50  comes into blocking contact with a first actuating surface  32   a  provided at the free end of an actuating arm  31   a  of the locking member  30   a . Thereby, upon movement of the connector housing  10  in mating direction into the retainer  50 , the locking members  30   a ,  30   b  remain un-moved, i.e. they are hindered from moving in the mating direction since the first actuating surface  32   a  rests on stop member  51 . Due to this blocking of the locking members  30   a ,  30   b  (due to the symmetrical arrangement, also the locking member  30   b  rests on a corresponding stop member  51  of the retainer  50 ) the locking members  30   a ,  30   b  will bias the spring  40  when the connector housing  10  is moved into the mated position. In the position shown in  FIG. 7 , the spring arms  41   a ,  41   b  of the spring  40  are thus under high tension and basically in the same position as shown in  FIGS. 3 and 4 . However, since the locking members  30   a ,  30   b  still rest firmly on the stop member  51 , the spring  40  cannot yet move the locking members  30   a ,  30   b  into the locked position shown in  FIGS. 1, 2 and 8 . 
     This is accomplished by means of an inclined deflection surface  17  provided in the connector housing  10 . This inclined deflection surface  17  comes into contact with a second actuating surface  33   a  of actuating arm  31   a  at the end of the mating process. A corresponding surface will have the same effect on actuating arm  31   b . When this happens, the inclined deflection surface  17  will push the actuating arm  31   a  of the locking member  30   a  outwardly, i.e. away from the plug-in portion  13 . The skilled person will recognize that thereby the first actuating surface  32   a  will be lifted from the stop member  51  and the locking members  30   a ,  30   b  are released and the tensioned spring  40  will automatically move the locking members  30   a ,  30   b  in their locked position as shown in  FIGS. 1, 2 and 8 . The skilled person will understand that the locking members  30   a ,  30   b  are only released after the latching arms  20   a ,  20   b  of the connector housing  10  can snap into the latching groove  55  of the corresponding counter-connector (i.e. it is in its latched position). 
     One can further see from  FIG. 8  how the actuating arm  31   a  of locking member  30   a  is now arranged between the latching arm  20   a  and a portion of the retainer  50 , respectively between the plug-in portions  13 . In the position shown in  FIG. 8 , it is not possible to move the latching arm  20   a  inwardly, i.e. towards the plug-in portion  13  so that it is impossible to bend the latching arm  20   a  out of the locking engagement with latching groove  55 . The same applies for the not shown latching arm  20   b  and locking member  30   b . An un-mating of the two connectors is only possible, after an operator manually releases the secondary locking means  30 , i.e. both locking members  30   a ,  30   b , by pulling it against the mating direction and the biasing force of spring  40 . 
     Reference number  18  denotes electrical female terminals provided in the plug-in portion  13 . The inventive concept of providing a locking means in form of two distinct locking members  30   a ,  30   b  allows a secure and reliable secondary locking of the mating, even if the primary locking means are only partially locked. The skilled person will thus recognize that the spring  40  of the illustrated embodiment is only an advantageous feature but not necessary for the inventive concept. 
     LIST OF REFERENCE NUMERALS 
     
         
           10  Connector Housing 
           11  Cover 
           12  Main body of connector housing 
           13  Plug-in portion 
           14  Electrical cables 
           15  Latch connection 
           16  Ferrite element 
           17  Inclined deflection surface 
           18  Electrical female terminals 
           20   a ;  20   b  Latching arms 
           30  Secondary locking means 
           30   a  locking member 
           30   b  locking member 
           31   a ;  31   b  Actuating arm of the locking members 
           32   a  First actuating surface 
           33   a  Second actuating surface 
           40  Spring 
           41   a ;  41   b  Spring arms 
           42  Spring coil 
           43  U-shaped frame 
           50  Retainer (part of counter-connector) 
           51  Stop member 
           52  Socket housing 
           55  Latching groove 
           62  Contact insertion length