Abstract:
A plug for a socket of an airbag is disclosed. The plug has a position assurance member having a movable member and a static member and the position assurance member is movable between a transport position and an end position by moving the movable member in relation to the static member. The plug also has a shorting contact, a flow of current in the shorting contact being possible in the transport position while the flow of current is not possible in the end position. The end position is attainable only when the plug is inserted into the socket.

Description:
CROSS-REFERENCE TO RELATED APPLICATION DATA 
   This application claims the benefit of the earlier filed International Patent Application No. PCT/EP2006/008927 having a filing date of Sep. 13, 2006 and that claims the benefit of the earlier filed German Patent Application No. DE 10 2005 043 903.9 having a filing date of Sep. 14, 2005. 
   FIELD OF THE INVENTION 
   The present invention relates to the field of plugs, and more particularly, to the field of plugs for airbags. 
   BACKGROUND 
   U.S. Pat. No. 6,276,953 B1 describes a plug of the type in which a sparking contact normally provided in an ignition coil is integrated into the plug. A shorting contact is broken so that current cannot flow in the shorting contact by pushing in a position assurance member, which is fitted at a side of the plug. When the plug is not inserted, the position assurance member is in an initial position in which current can flow in the shorting contact. Pushing the position assurance member into the plug and hence breaking the shorting contact so that current can not flow in the shorting contact is not possible in the initial position. 
   It is only by inserting the plug into the socket that a flexural member, which has prevented the position assurance member from being pushed in, is removed and that the shorting contact can be broken so that current cannot flow in the shorting contact. At the same time, an arm of the position assurance member fixes the plug in the socket and prevents the plug from being removed from the socket. Moving the shorting contact into the plug increases the complexity of the plug and is, moreover, not equally suitable for all customary sockets. It also impairs handling of the plug. 
   In the case of a plug known from EP 0 600 418 B1, a shorting contact located in a socket of an airbag is broken when the plug is inserted into the socket. This takes place when a front end of a plastic casing of the plug is pushed between a contact pin and a contact spring of the socket. When the plug is plugged in, the plug is initially inserted into the socket until the socket meets resistance. The plug is then pushed with force past the resistance until the plug breaks the shorting contact so that current cannot flow in the shorting contact and engages with several projections on the socket. As it engages, the plug is fixed on the socket. Since fixing and breaking of the shorting contact takes place simultaneously, measurements, for example, for testing or checking purposes are not possible once the plug is inserted. This is a marked disadvantage. 
   SUMMARY 
   The present invention relates to, in one embodiment among others, a plug for a socket of an airbag. The plug has a position assurance member having a movable member and a static member and the position assurance member is movable between a transport position and an end position by moving the movable member in relation to the static member. The plug also has a shorting contact, a flow of current in the shorting contact being possible in the transport position while the flow of current is not possible in the end position. The end position is attainable only when the plug is inserted into the socket. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention is described herein with reference to the following figures wherein: 
       FIG. 1  is an exploded view of a plug in accordance with the invention showing a position assurance member removed from the plug, 
       FIG. 2  is a partial sectional view of the plug in accordance with the invention with the position assurance member inserted therein in a transport position, 
       FIG. 3  is a partial sectional view of the plug in accordance with the invention showing the plug plugged into a socket and the inserted position assurance member in the transport position, and 
       FIG. 4  is a partial sectional view of the plug in accordance with the invention showing the plug plugged into the socket and the inserted position assurance member in an end position. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   It is therefore desirable to develop a plug  1  that has a simple construction, is easy to handle, and enables purposive breaking of the shorting contact  34  at a given moment in time. 
     FIG. 1  shows an embodiment of a plug  1  in accordance with the invention with a position assurance member  2  illustrated separately. In this embodiment, the plug  1  has first electrical leads  3  and second electrical leads  4  that extend inside the plug  1 . At least one of the first electrical leads  3  and second electrical leads  4  is connected to a choke. 
   The position assurance member  2  is substantially bow shaped and includes a static member  5  and a movable member  6 . The movable member  6  of the position assurance member  2  has opposing substantially V-shaped spring members, specifically, first spring members  9  and second spring member  10 , which are connected with each other at an activator end  11  of each via an activator  12  that is substantially horizontal. At an opposing plug arm end  13 , first spring member  9  and second spring member  10  each have an opening and an abutment member  14 , which when the position assurance member  2  is inserted into the plug  1  comes to rest on a shoulder  15  of the plug  1  to serve as an abutment for the first spring member  9  and the second spring member  10 . 
   Starting from the activator  12 , an arm  16  that is substantially wide and extends downward and approximately perpendicularly to the activator  12 . At an upper end of the arm  16  and in the immediate vicinity of the activator  12 , the arm  16  is provided with a first catch  17  and a second catch  18 , both being downward sloping, and which on insertion into a first recess  19  of the plug  1 , engage the plug projection  30  of the plug  1 . At a lower end of the arm  16  and away from the activator  12 , the arm  16  divides into two finger-like extensions, specifically, a first extension  20  and a second extension  21  which are connected by a base  22  that runs approximately at a right angle to the first extension  20  and the second extension  21 . At tips  23  thereof, the first extension  20  and the second extension  21  are slightly beveled. 
   In this embodiment of the invention the static member  5  of the position assurance member  2  consists of substantially wide plug arms, specifically, first plug arm  24  and second plug arm  25 , which in relation to the a longitudinal axis  26  of the plug  1  are arranged approximately opposite each other. The first plug arm  24  and second plug arm  25  are slightly rounded to adapt to the shape of the socket  33 . In addition, each of the first plug arm  24  and second plug arm  25  has a plug arm projection  27 , which is approximately trapezoidal in cross section that also adapts to the slightly rounded shaped of the first plug arm  24  and second plug arm  25 . 
   In this embodiment, the position assurance member  2  is made from plastic, and the movable member  6  and the static member  5  of the position assurance member  2  are made in one piece. It is therefore easy to manufacture the position assurance member  2  by, for example, injection molding or another casting process. Alternatively, the position assurance member  2  can be made of several components. In this case, care must be taken that at least the finger-like first extension  20  and second extension  21  consist of an electrically non-conductive material. 
     FIG. 2  shows the plug  1  with the position assurance member  2  inserted into the first recess  19 . The position assurance member  2  is in an initial position or transport position  28  in  FIG. 2 . The first plug arm  24  and second plug arm  25  of the static member  5  of the position assurance member  2  rest in each case on a stop  29  of the plug  1 . The first plug arm  24  and second plug arm  25  are supported by first spring arms  31  of the plug  1 , which abut against an inside of the first plug arm  24  and second plug arm  25 . 
   In this position, the second catch  18  locks behind a plug projection  30  of the plug  1  adjacent to a second spring arm  36  of the plug  1 . In this embodiment, the second spring arm  36  engages between the first extension  20  and the second extension  21  and abuts against the base  22  of the first extension  20  and the second extension  21  of the movable member  6  of the position assurance member  2 . The transport position  28  of the position assurance member  2  is thus unequivocally determined and fixed by the stops  29 , the second catch  18 , and the second spring arm  36 . 
     FIG. 3  shows the plug  1  with the position assurance member  2  in the transport position  28  and plugged into the socket  33 . The socket  33  has a shorting contact  34 . In this position, the plug projections  30  and the first plug arm  24  and second plug arm  25  engage in second recesses  32  of the socket  33 . 
   A contact spring  35  of the shorting contact  34  is in an initial position in the transport position  28  such that a current flow is possible via the shorting contact  34 . 
   When the plug  1  is plugged into the socket  33 , second spring arm  36  of the plug  1  is disengaged from the first extension  20  and the second extension  21  of the movable member  6  of the position assurance member  2  and releases the base  22  of the first extension  20  and the second extension  21  and hence the movable member  6  of the position assurance member  2 . The position assurance member  2  can now be moved further in a direction of the shorting contact  34 . 
     FIG. 4  shows the plug  1  with the position assurance member  2  in an end position  37  wherein the plug  1  is plugged into the socket  33 . The position of the static member  5  of the position assurance member  2  in the end position  37  corresponds to the position of the static member  5  in the transport position  28 . The plug arm projections  27  of the first plug arm  24  and second plug arm  25  remain engaged in the second recesses  32  in the socket  33  in the end position  37 . Compared with the transport position  28 , the movable member  6  of the position assurance member  2  is shifted downwards in a direction of the socket  33 . The first catch  17  is now engaged with the plug projection  30  of the plug  1 . In the end position  37 , compared with the transport position  28 , the first extension  20  and the second extension  21  are displaced slightly downward and press against the contact spring  35  of the shorting contact  34  of the socket  33 . The shorting contact  34  is therefore broken. 
   The method of use of the plug  1  according to the invention illustrated in  FIGS. 1-4  will now be explained. 
   The position assurance member  2  is inserted into the recess first  19  of the plug  1  and pushed downward until the tips  23  of the first plug arm  24  and second plug arm  25  abut against the stops  29  of the plug  1 . At the same time, the abutment members  14  of the first spring member  9  and the second spring member  10  of the movable member  6  of the position assurance member  2  come to abut against the shoulders  15 . Because the first plug arm  24  and second plug arm  25  of the static member  5  and the movable member  6  of the position assurance member  2  are formed in one piece, the first plug arm  24  and second plug arm  25  have a spring effect. When pushing in the position assurance member  2 , the first plug arm  24  and second plug arm  25  are pushed over the first spring arms  31  of the plug  1  and thus are additionally pre-tensioned. 
   By applying pressure to the activator  12 , the movable member  6  of the position assurance member  2  is shifted into the transport position  28 . The compressive force is hereby taken up via the first spring member  9  and the second spring member  10  as well as the abutment members  14  on the shoulder  15  of the plug  1 , which serves as an abutment. At the same time, the second catch  18  engages the plug projection  30  of the plug  1 . The initial tension of the first spring member  9  and the second spring member  10  keeps the second catch  18  engaged. Thereby, the plug  1  and the position assurance member  2 , respectively, are fixed in the transport position  28  in a direction of the spring tension. Fixing in the opposite direction is done by the second spring arm  36 , which engages between the first extension  20  and the second extension  21  and thus blocks any movement of the movable member  6  of the position assurance member  2  in a plug-in direction R of the plug  1 , as shown in  FIGS. 3-4 . The transport position  28  of the plug  1  is thus fixed in both directions and protected against any inadvertent actuation. 
   When inserting the plug  1  into the socket  33 , the plug arm projections  27  of the first plug arm  24  and second plug arm  25 , which are pre-tensioned by spring power, lock into the second recesses  32  in the socket  33  and fix the plug  1  in the socket  33 . At the same time, the second spring arm  36  is displaced from the initial position and releases the first extension  20  and the second extension  21  of the movable member  6  of the position assurance member  2 . The movable member  6  of the position assurance member  2  can now be moved further down in the plug-in direction R of the plug  1  by applying a pressure on the activator  12 . The pressure is supported by the first spring member  9  and the second spring member  10  on the plug  1 . Simultaneously, the first extension  20  and the second extension  21  are pushed further down and thereby pressed against the contact spring  35  of the shorting contact  34  of the socket  33 . The latter is thus displaced from its initial position and the shorting contact  34  is broken. On reaching the end position  37 , the first catch  17  locks into the plug projection  30  of the plug  1 . 
   During displacement of the movable member  6 , static member  5  of the position assurance member  2  remains in its initial position. In this way, the end position  37  of the plug  1  and the position assurance member  2 , respectively, is fixed and secured against loosening. 
   Through the separately mountable position assurance member  2  construction, the remainder of the plug  1  can be kept simple. The static member  5  of the position assurance member  2  ensures good guidance of the plug  1  when inserting the plug  1  into the socket  33  and good fixing of the plug  1  therein. The movable member  6  of the position assurance member  2  allows good power transmission and thereby good and secure breaking of the shorting contact  34  so that current cannot flow in the shorting contact  34 . Due to the functional division of the position assurance member  2 , the static member  5  as well as the movable member  6  can be designed specifically for the function to be fulfilled by each. 
   When the movable member  6  of the position assurance member  2  has a toggle mechanism, good power transmission is ensured. 
   The movable member  6  of the position assurance member  2  can advantageously be designed as one piece, thereby simplifying the construction of the plug  1 . 
   When the movable member  6  of the position assurance member  2  is designed as a spring member which pre-tensions the movable member  6  in direction of the transport position  28 , the position assurance member  2  is always kept in the transport position  28  and is protected, for example, from being inadvertently moved during transport. 
   When the position assurance member  2  and the static member  5  of the position assurance member  2  are designed as one piece, the construction of the plug  1  is simplified, and moreover, the plug  1  is easily manufactured, for example, by injection molding. 
   At least one catch can advantageously be provided on the movable member  6 , with the help of which the position assurance member  2  can be fixed in the transport position  28 . In this way, the position assurance member  2  is protected from inadvertent actuation, for example, during transport. 
   When at least two catches are provided on the movable member  6  of the position assurance member  2 , with the first catch  17  serving to fix the position assurance member  2  in the transport position  28  and the second catch  18  serving to fix the position assurance member  2  in the end position  37 , the position assurance member  2  can be fixed both in the transport position  28  and the end position  37  and therefore be protected from unintentional actuation and unintentional loosening, respectively, of the position assurance member  2 . 
   When the movable member  6  of the position assurance member  2  can be moved in parallel with a direction in which the plug  1  is inserted into the socket  33 , handling of the plug  1  is simplified. It is possible to insert the plug  1  into the socket  33  as well as to shift the position assurance member  2  into the end position  37  with one movement of the hand. 
   With the plug  1  being outside the socket  33 , the movable member  6  of the position assurance member  2  can abut against a shoulder  15  of the plug  1 . Therefore, as long as the plug  1  is outside the socket  33 , the position assurance member  2  is fixed in the transport position  28 . 
   With the plug  1  being outside the socket  33 , the movable member  6  of the position assurance member  2  can be fixed in the transport position  28  by the shoulder  15  of the plug  1 . This prevents inadvertent shifting of the position assurance member  2  into the end position  37 , for example, during transport or handling. 
   When the shoulder  15  of the plug  1  is designed as a movable spring member, the shoulder  15  can be shifted during insertion of the plug  1  into the socket  33  and thus be disengaged from the position assurance member  2 . When removing the plug  1  from the socket  33 , the shoulder  15  returns to its initial position with the help of spring tension and so ensures proper functioning of the plug  1 . 
   The shoulder  15  can advantageously be movable in a state in which it releases the movable member  6  of the position assurance member  2 . This enables the position assurance member  2  to be shifted into the end position  37 . For example, the shoulder  15  can be moved by a contact face of the socket  33  when the plug  1  is inserted into the socket  33 . 
   When the static member  5  of the position assurance member  2  has at least two plug arms, which in relation to a longitudinal axis  26  of the plug  1 , are approximately opposite each other and slant outward, the plug arms slide along the socket wall as the plug  1  penetrates the socket  33  to ensure good guidance of the plug  1 . At the same time, the plug  1  is fixed in the socket  33  by the outward slanting plug arms. 
   When the static member  5  of the position assurance member  2  has at least one projection which engages in a second recess  32  in the socket  33  when the plug  1  is inserted therein, the plug  1  is locked in the socket  33  when the plug  1  is inserted into the socket  33  and is thus secured against inadvertent loosening. 
   When the static member  5  of the position assurance member  2  has at least two projections which engage in second recesses  32  in the socket  33  when the plug  1  is inserted therein and which in relation to the longitudinal axis  26  of the plug  1  are approximately opposite each other, good power transmission and thus good protection of the plug  1  in the socket  33  is ensured. 
   The plug  1  can have at least two spring arms which abut against an internal wall of the static member  5  of the position assurance member  2 . 
   The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents.