Abstract:
A housing for a device for mounting on an assembly surface, in particular a sensor module with a sensor for a motor vehicle, has a housing assembly surface, by way of which the housing may be brought into contact with the assembly surface and a contact socket with electrical contacts which may be electrically and mechanically connected with a complementary contact plug and running parallel to a housing plane in which the housing assembly surface is arranged. A locking device is provided with the following features: a detector for detecting a given position on the assembly surface when the housing is on contact with the assembly surface by way of the housing assembly surface, a blocking device for releasing or blocking the mechanical and/or electrical connection between the contact socket and the contact plug. The connection is released by the blocking device when the housing is in contact with the given position on the assembly surface by way of its housing assembly surface.

Description:
BACKGROUND OF THE INVENTION 
   Field of the Invention 
   The invention relates to a housing for a device for mounting on an assembly surface, in particular a sensor module comprising a sensor for a motor vehicle. 
   Where the following description refers to a sensor module, this should be considered to be an example only. The invention may be generally used, independently of the purpose of the device, for all housings for mounting on an assembly surface. 
   In the embodiment of the device provided with electronic components as a sensor module, depending upon the type of the sensor used, a precise positional arrangement of the device on the assembly surface and correct, functional electrical contacting of the device is necessary in order be able to guarantee the intended function. A side airbag sensor module is mounted in a motor vehicle on a body component, such as, for example, the so-called B-pillar, a sill or a seat cross member. 
   The housings are generally made of a plastic. This has the advantage that, due to the simple production by means of an injection-molding procedure, it is possible to provide customized features, such as for example fixing points and positioning pins, for ensuring the correct installation of the sensor module. 
   The positional accuracy of the device, which is of essential significance for correct functioning, is ensured by the correct seating of the screw connection and the positioning pin, with it being necessary to insert the positioning pin in an opening in the assembly surface provided for this purpose. Only when the positioning pin is placed in the opening, is correct fixing of the device on the assembly surface by means the screws possible. In order to verify whether the installation of the sensor module was performed correctly, the tightening torque of the screw(s) is checked during the fixing of the housing on the assembly surface by means of the screw(s). This takes place under the assumption that only when the housing lies correctly on the assembly surface and the screw(s) are correctly engaged in a corresponding opening of the assembly surface can the specified torque be detected. 
   In some cases, however, it is possible that the stipulated torque of the screws can be detected even though the housing is not in its correct position. Therefore, although the housing mounted on the assembly surface appears to be positionally accurate, this is not actually the case. Under unfavorable circumstances, this may result in incorrect signals being received by the sensor. It is therefore not possible to exclude the possibility of a control unit which evaluates the signals transmitted by the sensor performing an evaluation on the basis of false or falsified signals. In the case of a sensor module for an airbag satellite, the “wrong” evaluation decision could result in the non-activation of an airbag in the case of an actual crash or activation at the wrong time etc. 
   BRIEF SUMMARY OF THE INVENTION 
   It is the object of the present invention to disclose a housing for a device for mounting on an assembly surface, in particular a sensor module comprising a sensor for a motor vehicle, which does not have the aforementioned drawbacks. 
   This object is achieved by a housing with the features of claim  1 . Advantageous embodiments are described in the dependent claims. 
   A housing according to the invention for a device for mounting on an assembly surface, in particular a sensor module comprising a sensor for a motor vehicle, has the following features: 
   A housing assembly surface, by means of which the housing may be brought into contact with the assembly surface. A contact socket with electrical contacts which may be mechanically and electrically connected to a complementary contact plug and runs parallel to a housing plane, in which the housing assembly surface is arranged. A locking device having a detector means and a blocking means. The detector means is designed to detect a given position on the assembly surface when the housing is in contact with the housing assembly surface on the assembly surface. The blocking means is designed to release or block the mechanical and/or electrical connection between the contact socket and the contact plug, with the connection being released by the blocking means when the housing is in contact with the given position on the assembly surface by means of the housing assembly surface thereof. 
   The invention is therefore based on the principle of only being able to establish a mechanical and/or electrical connection between the contact socket and the contact plug when the housing is in positionally accurate contact with the assembly surface. However, if the housing does not adopt the given position on the assembly surface, this will be “indicated” during the assembly of the housing so that a mechanical connection between the contact plug, with which the electrical connection between the electronic components of the device and another component, for example a control device, is established, and the contact socket is not possible. This establishes a mechanical tangible feedback as early as during the assembly of the housing. During an electrical functional test, signals from the electronic components of the device cannot be evaluated since no electrical plug-in connection is present. This significantly increases the reliability and the verification as to whether the mounting is incorrect or not. In addition, the verification with respect to correct installation at the given position can take place blindly, that is without a visual inspection, since the feedback is tangible to an assembler. 
   In one embodiment, the locking device is designed to scan the surface of the assembly surface in order to determine whether the housing is in contact with the given position on the assembly surface by means of the housing assembly surface thereof. Expediently, the locking device is designed for the mechanical scanning of the assembly surface. This results in a structurally particularly simple embodiment of the locking device. 
   In one embodiment, the locking device is designed as a tongue which is deformable under the action of force and arranged on the housing as a type of cantilever arm extending between the contact socket and the housing plane of the housing assembly surface. The detector means and the blocking means are arranged on opposing sides, in particular on a free end, of the tongue. This enables the blocking means to function in reaction to the detector means. 
   In a further embodiment, it is provided that the tongue is in unloaded condition when the housing is in contact with the given position on the assembly surface by means of the housing assembly surface thereof and is in loaded condition when the housing is not in contact with the given position on the assembly surface by means of the housing assembly surface thereof. As the result of the action of a force, which is exerted through the assembly surface onto the locking device when the housing is located on the assembly surface, a deformation occurs, which serves to control the blocking means. 
   Expediently, the detector means is arranged on a side of the tongue facing the housing plane and protrudes in unloaded condition of the tongue over the housing plane of the housing assembly surface. This ensures that the detector means bring about a deformation of the tongue which in turn serves to control the blocking means. This enables mechanical and/or electrical contacting of the contact plug with the contact socket to be prevented. On the other hand, an unloaded condition of the locking device is necessary in order to release access to the contact socket. This can be achieved by the fact that an opening is provided in the assembly surface into which the detector means engages when the housing is in contact with the given position on the assembly surface. In this case, the detector means also adopts the function of a locking device. 
   Expediently, the blocking means is arranged on a side of the tongue facing the contact socket and in unloaded condition of the tongue it is located outside a plug-in area of the contact plug when the contact plug is plugged onto the contact socket. In loaded condition of the tongue, when the housing is not in contact with the given position on the assembly surface by means of the housing assembly, the blocking means is located inside the plug-in area of the contact plug so that the plugging-on of the contact plug onto the contact socket is prevented. The physical arrangement of the blocking means then takes place as a direct reaction to the detector means. 
   The plug-in area of the contact plug should be understood as meaning the region which is necessary in order to be able to plug the contact plug onto the contact socket. Substantially, the plug-in area corresponds to the thickness of a housing wall of the contact plug and hence approximately to the dimension formed between the circumference of the contact socket and the blocking means when the tongue is in unloaded condition. 
   In one embodiment, the detector means is embodied as a projection having a back arranged at an angle with respect to the housing plane, with the angle being selected in such a way that, in loaded condition of the tongue in which the housing is not in contact with the given position on the assembly surface, the back runs substantially parallel to the housing plane. This has the advantage that when the detector means is moved laterally to the assembly surface it creates a slight friction. 
   In a further embodiment, the blocking means is embodied as a projection having a back, which is arranged at an angle with respect to the housing plane, with the angle being selected in such a way that, in loaded condition in which the housing is not in contact with the given position on the assembly surface, the back runs substantially parallel to the housing plane. This results in a skewed plane of the back when the detector means is in unloaded condition. This facilitates the plugging-on of the contact plug onto the contact socket. 
   Preferably, the distance between the contact socket and the blocking means is greater than a housing thickness of the contact plug and smaller than the sum of the housing thickness of the contact plug and the height of the projection serving as a detector means. One advantage of this variant consists in the fact that the detachment of the housing from the assembly surface is prevented as long as the contact plug remains plugged-on. This means that detachment with respect to the given position from the given position of the housing is no longer possible as soon as the contact plug is plugged onto the contact socket. 
   In an expedient embodiment, the width of the locking device parallel to the housing plane is such that deformation parallel to the housing plane is not possible. Hereby, the width of the locking device can approximately correspond to the width of the contact socket. 
   In a further expedient embodiment, the circumference of the housing assembly surface has a substantially trapezoidal or wedge-shaped shape. The tapering preferably takes place in the direction of the contact socket. This enables assembly via a lateral plug-in unit into a stop of the assembly surface, which has a bend. The stop represents a type of guide into which the housing may be pushed until the given position is reached. 
   A further embodiment envisages that at least one projection serving as an end stop runs in the orthogonal direction from the housing assembly surface to the housing plane of the housing assembly surface. This also adopts the role of a guide, which facilitates easier positioning of the housing on the assembly surface until the given position is reached. 
   It is further preferable for the housing and the locking device to be formed from a moldable plastic and the locking device to be an integral component of the housing. 
   The invention will be described in more detail below with reference to an exemplary embodiment in the drawings which show: 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       FIGS. 1A-1C  A housing according to the invention for a sensor module in a side view, top view and frontal view 
       FIG. 2  A top view of an assembly surface on which the housing according to the invention is to be mounted 
       FIG. 3  A sectional view of a housing according to the invention which is arranged on an assembly surface outside its given position 
       FIGS. 4A-4C  A side view, a top view and a front view of the housing placed on the assembly surface, wherein this is not in its given position 
       FIG. 5  A section through a housing according to the invention which is arranged on an assembly surface and is located in a given position 
       FIGS. 6   a - 6 C A side view, a top view and a front view of the housing according to the invention which is located in the given position on the assembly surface 
   

   DESCRIPTION OF THE INVENTION 
   The depiction in the  FIG. 1A to 1C  shows a housing according to the invention  10  for a sensor module  1  in a side view, a top view and a front view. The sensor module  1  can be, for example, a so-called side airbag satellite sensor. In the interior of the housing, and not evident from the figures, a plurality of electronic components and a sensor are arranged on a board to detect an acceleration, a structure-borne signal or the like. Since the design of the sensor module and the components required for this are of no significance for the present invention, no detailed description will be given at this point. In principle, the housing according to the invention  10  can be used for any type of electronic circuit or any electronic device for which precise positioning on an assembly surface is required. 
   The housing  10  has a contact socket  14  which comprises contact pins  15  in a known way. This example of an embodiment depicts two contact pins  15 , with this only being shown by way of example. The contact socket  14  runs parallel to a housing plane  18 . A housing assembly surface  11  of the housing is placed in the housing plane  18 . The housing  10  is mounted with the housing assembly surface  11  on the assembly surface (described below). Furthermore, two opposing projections  17  are provided on the contact socket  14 . As will become clear from the following description, these are necessary for the assembly with a contact plug, with the projections  17  serving as a barb or stop for the contact plug. In the top view ( FIG. 1B ), the projections  17  are approximately wing-shaped. 
   A locking device  20  runs between the contact socket  14  and the housing plane  18 . The locking device  20  is embodied as tongue  30  which is deformable under the action of force and arranged on the housing as a type of a cantilever arm. The tongue  30  is connected to the housing  10  on a bearing  21  which is arranged above the housing plane  18 . 
   Preferably, the housing  10  and the locking device  20  are formed in one piece and integrally from a moldable plastic. 
   The tongue  30  runs substantially parallel to the housing plane  18  beyond the end of the contact socket  14 . Arranged on two opposing sides of the tongue  30  on the end of the tongue  30  facing away from the bearing  21  are two projections  22  and  26 . The projection  22 , which arranged on the side of the tongue  30  facing the housing plane  18 , represents a detector means, which, in unloaded condition of the tongue, runs beyond the housing plane  18 . This is clearly evident in  FIG. 1A . The projection  26  facing the contact socket  14  represents a blocking means. 
   The hollow (see reference number  25  in  FIG. 3 ) detector means  22  has a back  24 , which is arranged at an acute angle relative to the housing plane  18 . When the tongue  30  is loaded, the oblique arrangement of the back  24  serves to provide a substantially parallel alignment to the housing plane  18 . Furthermore, the detector means  22  has a contact surface  23 , which, as is evident from the following description of the figures, enables the housing  10  to be locked to the assembly surface when the housing  10  is arranged in the given position on the assembly surface. 
   The blocking means  26  has a contact surface  27 , which is arranged perpendicular to the housing plane  18  and outside the contact socket  14 . The contact surface  27  is arranged in a plug-in area of the contact plug  14  when the tongue  30  is in loaded condition. A back  28  is also arranged at an acute angle relative to the housing plane  18 . If the tongue  30  is in unloaded condition shown in  FIG. 1A , the plugging-on of the contact plug onto the contact socket  14  is made easier. For increased stability, two opposing flange-shaped sections  29  are also arranged on the blocking means  26 . 
   The width of the tongue  30  is dimensioned in such a way that lateral deflection, which means deflection parallel to the housing plane  18 , is not possible. In this exemplary embodiment, therefore, the width of the tongue  30  approximately corresponds to the width of the contact socket  14 , which is clearly evident from  FIGS. 1B and 1C . 
   By way of example, also embodied on the housing  10  are three openings  19 , which are used for the accommodation of coding pins (see  FIG. 1B ). The coding pins can be used, for example, to mark the type and/or arrangement of the sensor for the assembly. 
     FIG. 1B  also clearly reveals the wedge-shaped or trapezoidal shape of the circumference of the housing assembly surface (reference number  12 ). 
   Embodied on the lower side of the housing  10  are two projections  13  serving as end stops and guides (see  FIGS. 1A and 1C ), which protrude out of the housing assembly surface. 
   The wedge-shaped or trapezoidal design of the circumference of the housing assembly surface is linked to the type of fastening of the housing  10  of the sensor module  1  on the assembly surface.  FIG. 2  shows by way of example a top view of an assembly surface  2 . Two opposing stops  6  can be identified, each of which having a bend, facing each other. Provided in the region of the stops are openings  7  which engage with the two end stops  13  embodied on the lower side of the housing  10 . As is immediately evident, the stops  6  are arranged at an angle to each other which is adapted to match the circumferential shape of the housing assembly surface  12 . The assembly surface  2  also has an opening  3  into which the detector means  22  latches as soon as the housing  10  has achieved its given position on the assembly surface  2 . 
   The interaction of the housing according to the invention with the described assembly surface  2  is shown more clearly in  FIGS. 2 to 6 . 
   Hereby,  FIGS. 3 and 4A  to  4 C show a situation in which the housing  10  is in contact with the assembly surface  2 , wherein the given position has not yet been achieved.  FIG. 3  hereby shows a section through the system formed, while  FIGS. 4A ,  4 B and  4 C show a side view, a top view and a front view respectively. 
   Reference number A denotes a direction of movement of the housing  10 , with it being necessary to push the housing  10  along the stops  6  of the assembly surface  2  in the direction of the given position thereof. 
   Reference number B denotes the direction of movement of the contact plug  40  which has to be performed for the mechanical and electrical contacting of the contact socket  14 . 
   The detector means  22  projecting over the housing plane  18 , in which the housing assembly surface  11  is placed, results in loading of the locking device  20  in the direction of the contact socket  14 . Hereby, the back  24  of the detection means  22  is substantially in full contact with the assembly surface  2 . The back  28  of the blocking means  26  is pressed in the direction of the contact socket  14  with this making it possible for them to come into contact. The contact surface  27  is hereby pushed into a plug-in area. This denies a contact plug  40  access to the contact socket  14  so that a mechanical and electrical contacting of contact socket  14  and contact plug  40  is not possible according to the intended purpose. 
   The contact plug  40  has a plug-in section  42  with hollow conductors  41 , into which the contact pins  15  of the contact socket  14  have to be introduced. Due to the blocking means arranged in the plug-in area, the plug-in section  42  cannot be fully pushed into the contact socket  14 . The contact surface  27  of the blocking means  26  functions as a stop and hence as a mechanical block for the contact plug  40 . 
   The contact plug  40  also has a coding pin  43  which is embodied on the side of the plug-in section  42 . The coding pin  43 , which can arrive at a stop at a shoulder  16  in the interior of the contact socket  14 , serves as an anti-rotation element. This ensures that the contact plug  40  can only be brought into contact with the contact socket  14  in a certain position. 
   Moreover, embodied in a rear section of the contact plug is a housing jacket  44  which, in the case of correct mechanical contacting with the contact socket  14 , reaches round the contact socket  14  so that, by means of a locking element  45 , locking with a projection  17  embodied as a barb or stop can take place. It is particularly clearly evident from  FIG. 4B  that the locking element  45 , which is embodied on the housing jacket  44  of the contact plug, can be brought into contact with the projections  17  on the contact socket  14  due to the position of the blocking means  26 . 
   On the other hand,  FIGS. 5 and 6A  to  6 C show a situation in which the housing  10  is arranged in the given position on the assembly surface  2  so that a mechanical and electrical contacting between contact plug  40  and contact socket  14  or the electrical conductors embodied therein can take place. 
   As seen best in  FIG. 5 , the detector means  22  engages in the opening  3  of the assembly surface  2 . This produces sufficient space (designated above as the plug-in area) between the blocking means  26  and the contact socket  14  for the contact plug  40  to be plugged onto the contact socket  14 . The distance between the blocking means  26  and the circumference of the contact socket  14  is hereby selected in such a way that a smaller gap forms between the blocking means  26  and the circumference of the housing jacket  44 . The oblique back  28  hereby facilitates the guidance and the plugging-on of the contact plug  40  onto the contact socket  14 . Since a contact surface  23  is in engagement with the border of the opening  3 , due to the selected dimensions, the detector means  22  now serves as a locking device for the housing  10 . The detachment of the housing  10  from the assembly surface  2  is not possible as long as the contact plug  40  is plugged onto the contact socket  14 . 
   In order to avoid the incorrect mounting of a housing for an electrical device and to make installation as simple and reliable as possible, the invention proposes the embodiment of a locking mechanism for the contact plug in the form of a snap hook on the housing. This is preferably embodied in one piece and integrally on the housing so that additional parts and assembly costs are dispensed with. 
   As long as the housing is not mounted in its given position (final position), the locking device designed as a snap hook is elevated and blocks the plugging-on of the contact plug. An electrical contact between the device and a central control device is then not possible, which can be detected during a functional test. 
   However, when the housing is located in its correct, given position (final position), the locking device designed as a hook latches in and releases the access for the plugging-on of the contact plug. If the contact plug is plugged on, this again blocks the locking mechanism, which can then no longer be opened. This makes it impossible to disassemble the housing from the assembly surface without previously having detached the contact plug.