Abstract:
The invention concerns an electrical pin-and-socket connector, in particular for use between a socket (primer) and an electrical control unit for a retention system in motor vehicles, which provides for the locking of the pin-and-socket connector with a long-lasting connecting and engaging and disengaging ability in its locked position, to a great extent tension-free.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention concerns an electrical pin-and-socket connector, in particular for use between a socket (primer) and an electrical control unit for a retention system in motor vehicles, for example an airbag. 
   2. Description of the Related Art 
   Such a pin-and-socket connector should have the smallest possible dimensions due to the meager space available in the retention system. From this it follows that individual components of the pin-and-socket connector or associated socket, if applicable, are to have only an extremely small structural size, yet with respect to use involving safety regulations (for example, belt tighteners, airbags) a light assembly on the one hand and a high operational safety on the other is required. 
   This is so especially with respect to the locking of the connector and socket, whereby the contact elements of the components in the locked state must make secure contact. In the same way, the connector and socket may not inadvertently be detached from one another. 
   The known pin-and-socket connectors have a controlled latching bar, which is locked so it cannot operate in the initial position and can be moved only in the end position (locked position) if the pin-and-socket connector is inserted into the socket part (primer). The pin-and-socket connectors are essentially made of plastic, whereby the controlled latching bar is at least in part live in the locked end position. 
   If an external force acts on a plastic, the plastics behave in different ways. Thermoplasts react to an applied force with a continuing force effect (flowing). The flowing is nonreversible and is visible as a deformation. Duroplasts and elastomers do not display this behavior because only a reversible, elastic deformation takes place due to their complete cross-linkage. The flowing can occasionally lead to malfunctions of the latching bar. 
   If the pin-and-socket connector comes loose after some time and then needs to be put together again, putting it back together again can be problematic due to the remaining deformation of individual components. 
   SUMMARY AND OBJECT OF THE INVENTION 
   The task of the present invention is therefore to create an electrical pin-and-socket connector that can be put together again even after coming loose after a long time. 
   The basic idea of the present invention is to design the model and geometrical arrangement as well as the interaction of the individual components in such a way that at least in the end position or the locked position of the pin-and-socket connector the controlled latching bar or the secondary locking mechanism provides for the locking of the pin-and-socket connector to a great extent tension-free or essentially unstressed. 
   A locking arm of the secondary locking mechanism, designated hereafter as an actuator, produces the locking connection in the pre-lock position through at least one blocking rib, which works together with the case of the pin-and-socket connector. The secondary locking mechanism, which is formed from a basis plate and at least one of the essentially vertically extending operational elements (for example, the actuator), can be positioned in an L-shaped structural form of the pin-and-socket connector in such a way that through pressure on the basis plate the pin-and-socket connector is inserted in the primer or socket with contact connections and directly thereafter the secondary locking mechanism is immersed in the case through the release of a bar on the actuator. 
   In so doing, a shorting bar can be opened by an opening finger on the secondary locking mechanism. Through a guiding bar on the secondary locking mechanism the loosening of the primary locking mechanism from the socket can be prevented, as the guiding bar takes hold of the primary locking mechanism from behind. 
   To raise the safety and operational capability of the secondary locking mechanism it has four actuators with the corresponding bars and blocking ribs, whereby the actuators are positioned on the four corner points of the basis plate of the secondary locking mechanism. 
   Through the force-free end position of the actuator during the injection of the primer and the resulting prevention of the flowing of the material, the operational capability of the mechanism may be improved even after years of use. 
   In its most general working form the present invention concerns an electrical pin-and-socket connector with the following properties: 
   1. A case for receiving especially electrically connected contact elements for making contact with corresponding contact parts of the socket, whereby the case has a primary locking element to lock the case with the socket, 
   2. A secondary locking mechanism guided relative to the case with at least one actuator that projects essentially vertically from the basis plate of the secondary locking mechanism, 
   3. The secondary locking mechanism is capable of being moved back and forth between a pre-locking position for locking with the case and a locked end position for locking with the socket, 
   4. The actuator is shaped so it is springy and it is positioned in the end position so it works with a recess of the socket in such a way that the actuator is essentially unstressed and the secondary locking mechanism is positioned behind the primary locking device so it can take hold of it. 
   The construction is further simplified and accordingly space is saved as the actuator and primary locking mechanism lock into the same recess of the socket in the end position. The recess is preferably formed as an interior snap ring groove. 
   The activity involved in putting together the connector, pre-locked with the secondary locking mechanism, and the connector takes place accordingly in two stages: 
   First, the locking mechanism and case in the pre-assembled position are guided together; then the locking mechanism is released from the blocking position opposite to the case and can be pushed relative to it. 
   Further properties of the invention arise from the properties of the subclaims as well as the any other application documents. 
   The invention is explained in greater detail below by use of working examples. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In this connection the following are shown in schematic representation: 
       FIG. 1   a  is a cut-out side view of a pin-and-socket connector according to cut line B—B from  FIG. 1   b  in a pre-assembled state, separated from a socket, 
       FIG. 1   b  is a cut-out front view of the pin-and-socket connector according to cut line A—A from  FIG. 1   a  in a pre-assembled state, separated from the socket, 
       FIG. 1   c  is a perspective view of the pin-and-socket connector in a pre-assembled state, 
       FIG. 2   a  is a cut-out side view of a pin-and-socket connector according to cut line B—B in  FIG. 2   b  in an inserted, unsecured state, 
       FIG. 2   b  is a cut-out front view of the pin-and-socket connector according to cut line A—A in  FIG. 2   a  in an inserted, but not secured condition, 
       FIG. 2   c  is a perspective view of the pin-and-socket connector in an inserted, but not secured state, 
       FIG. 3   a  is a cut-out side view of a pin-and-socket connector according to cut line B—B from  FIG. 3   b  in an inserted and secured state, 
       FIG. 3   b  is a cut-out front view of the pin-and-socket connector according to cut line A—A in  FIG. 3   a  in an inserted, secured state, 
       FIG. 3   c  is a perspective view of the pin-and-socket connector in an inserted state, 
       FIG. 4  is a perspective view of a secondary locking mechanism, 
       FIG. 5  is a cut-out front view of the pin-and-socket connector according to cut line C—C in  FIG. 1   a  in a pre-assembled state, 
       FIG. 6  is a cut-out partial view of the pin-and-socket connector according to cut line C—C in  FIG. 2   a  in an inserted, not yet locked state, and 
       FIG. 7  is a cut-out front view of a connector according to cut line C—C from  FIG. 3   a  in an inserted and locked state. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   In the figures the same components or equally acting components are designated and represented by the same reference numbers. 
   The pre-assembly position represented in  FIGS. 1   a ,  1   b , and  1   c  shows an electrical pin-and-socket connector consisting of a case  10  and a secondary locking mechanism  20  in a pre-assembled state over a socket  50 , also designated as a primer or igniter. 
   The components are represented in greatly enlarged form and thus are not true to scale. The L-shaped connector represented  FIG. 1   a  has, for example, a height of about 10 mm and a width of about 20 mm. 
   In insertion direction S openings run in the case  10 , in which contact springs, which are not shown, are arranged and which make contact with the corresponding contact pins  52  of the socket  50  corresponding to the plug in the locking state of the plug and socket  50 . 
   To make the insertion process easier, the secondary locking mechanism  20  is positioned in the insertion direction S over a nozzle  15  of the case  10  and guided in the insertion direction S into the case  10 . Through such an arrangement a space-saving accommodation of the secondary locking mechanism can be realized. 
   The case  10  consists of the nozzle  15  and an upper part shaped like a cigarette box. It guides contact elements, if necessary, through a welded-on throttle and cable traction relief to further electrical components and has a separate cover  16 . The case  10  can be designed as one part or several parts. 
   The secondary locking mechanism  20  consists of an essentially rectangular basis plate  20   p , positioned parallel to the plane of the case  10 , with the basis plate having actuators  22  on its four corners extending in insertion direction S, a profile guide rib  21 , and two arms  23 , as is shown in the blow up in  FIG. 4 . 
   The case  10  has recesses and indentations for inserting, guiding, and securing the secondary locking mechanism  20  in its front section positioned over the nozzle  15 . In the insertion direction to the socket  50  runs the nozzle  15 , which has a shape adapted to the socket  50  (in the present case cylinder shaped). 
   The actuator  22  consists of a material that allows for a springiness of the actuator—for example, plastic. On the actuator  22 , which can also be designated as a stop lance, various projecting parts have been mounted, which are important for the function of the secondary locking mechanism  20 . 
   In delivery state, in which the secondary locking mechanism  20  is pre-assembled with the case  10 , as is shown in  FIGS. 1   a ,  1   b , and  1   c  and  5 , an upper projecting part  24 , working together with a corresponding projecting part  13  on the case  10 , prevents the secondary locking mechanism  20  from being pulled out of the case  10 . Below it the freedom of motion of the secondary locking mechanism  20  is limited in the case  10  by the middle projecting part  25 , which extends to the underpart of the case above the nozzle  15 . In the pre-assembled state all the components of the secondary locking mechanism  20  are positioned essentially without mechanical tension in the case  10 . 
   The case  10  has a primary locking mechanism  11 , which is positioned next to the nozzle  15  and which also extends in the insertion direction S. The primary locking mechanisms  11  are designed as two arms  11 , on whose ends detents  11   r  are mounted, which intermesh in a corresponding recess  55  of the socket  50  when the plug is inserted into the socket  50 . 
   The arms  11  are positioned in the end position between two actuators  22  on the short side of the basis plate  20   p , whereby the arms  11  are mounted on the case  10  and the actuators  22  on the secondary locking mechanism  20 . 
   Shortly before reaching the locking position of the detents  11   r  in the recess  55 , a lower slanted surface  26   f  of a lower projecting part  26  of the actuator  22  runs at a corresponding angle  50   s  of the socket  50 , as a result of which each actuator  22  is pressed inward against its spring force and as a result the middle projecting part  25  is moved away from the bearing surface of the case  10  and guided past the bearing surface, as one can see in  FIG. 6 . 
   In  FIG. 7  one can see that the middle projecting part  25  was guided past the case  10  and was locked into the depicted locked end position of the lower projecting part  26  of the actuator  22  in the recess  55  of the socket  50 . For the locking of the lower projecting part  26  a second recess can also obviously be provided in the socket  50 . To save space it is, however, advantageous to have the primary locking mechanism  20  lock into a common recess  55 . The recess  55  of the socket  50  can be designed as a ring-shaped groove. 
   In the locked end position the actuators  22  and also the other components of the secondary locking mechanism  20  and the primary locking mechanism  11  lock into the socket without mechanical tension free of force. 
   The profile guide rib  21  provides for the interruption of a shorting bar, which is not shown here, through the free end  21   e  of the profile guide rib  21 . The profile guide rib  21  serves, in addition, to guide the secondary locking mechanism  20  into a respective profiled recess or opening of the case  10  and the socket  50 . 
   The arm  23  provides for the locking of the primary locking device  11  in the locked end position of the electrical pin-and-socket connector by pushing the arm  23  when inserting the secondary locking device  20  between the nozzle  15  and the back side of the primary locking mechanism  11  that is turned away from the detent  11   r.    
   A guide bar  23   g  of the arm  23  serves to give further precision to the vertical guiding of the secondary locking mechanism  20  in the case  10  along the insertion direction S. 
   The basis plate  20   p  has on its underside recesses that lock into the corresponding projecting parts or ramps of the cover of the case so that the secondary locking mechanism  20  essentially lies on a plane with the cover of the case  10 . 
   LIST OF REFERENCE NUMBERS 
   
       
       
         
             10  case 
             11  primary locking mechanism 
             11   r  detent 
             13  projecting part 
             15  nozzle 
             16  cover 
             20  secondary locking mechanism 
             20   p  basis plate 
             21  profile guide rib 
             21   e  free end 
             22  actuator 
             23  arms 
             23   g  guide bar 
             24  upper projecting part 
             25  middle projecting part 
             26  lower projecting part 
             26   f  lower slanted surface 
             50  socket 
             50   s  angle 
             52  contact pins 
             55  recess 
           S insertion direction 
         
       
     
  
   Although certain presently preferred embodiments of the invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.