Abstract:
The invention relates to a fixing device ( 200 ) for fixing in an opening in a wall of a vehicle, said fixing device ( 200 ) having a support element ( 210 ) with at least one support lug ( 220 ). The fixing device ( 200 ) also comprises a retaining element ( 230 ) with at least one retaining arm ( 240 ) for fixing the fixing device ( 200 ) to the wall. To fix the fixing device ( 200 ) in relation to the support element ( 210 ), the retaining element ( 230 ) runs through the support element ( 210 ) and can rotate it the latter, the support lug ( 220 ) being designed to block the rotation of the support element ( 210 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a fixing device for fixing an element in an opening of a wall, as well as a method for fixing a fixing device to a wall. 
         [0002]    In the automobile industry, components, in particular sensors (for example for restraining systems), are fixed in various ways to the vehicle. Typically, fixing methods such as screwing, riveting and bonding are used. Specifically in sensors in applications where safety is critical, such as for example airbag systems, secure mounting is of crucial importance. Firstly, correct mounting has to be ensured when leaving the factory. At the same time, however, the sensor also has to remain securely mounted in the correct location and position or has to be replaceable in a safe manner over the entire service life, in the event of repairs, amongst other things. 
         [0003]    Thus in sensors which are available nowadays and which, for example, are fixed by a screw connection, in many cases the mounting is recorded. This may take place, for example, by the torque and rotational angle being monitored and registered during the screwing process. 
         [0004]    A sensor module is disclosed in the publication DE 199 23 985 A1, in which the housing of an air pressure sensor, which is used for side impact sensing, is fixed to a wall in the vehicle via fixing means, for example screws. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides a fixing device for fixing in an opening of a wall of a vehicle, the fixing device includes a support element with at least one support lug; and a retaining element with at least one retaining arm for fixing the fixing device to the wall, the retaining element being arranged in a rotatable manner through the support element for fixing the fixing device relative to the support element and the support lug being configured to block a rotation of the support element. 
         [0006]    The invention further provides a method for fixing a fixing device for fixing an element in an opening of a wall of a vehicle, the fixing device comprising a support element with at least one support lug and a retaining element with at least one retaining arm for fixing the fixing device to the wall, the retaining element being arranged in a rotatable manner through the support element for fixing the fixing device relative to the support element, and the support lug being configured to block a rotation of the support element. The method includes inserting the support lug and the retaining element into the opening in the wall; and rotating the retaining arm relative to the support element, in order to lock the fixing device to the wall, the support lug blocking a rotation of the support element. 
         [0007]    The present invention is based on the recognition that a simple, and at the same time secure, possibility of fixing an element to a wall is available by providing a possibility of fixing using retaining arms which are twisted when fixed to a rear face of the wall, to which the fixing device is intended to be fixed. Before the fixing, the retaining arms are rotated into a position in which they may be inserted through a hole of elongate configuration (an opening) in the wall, whereupon the retaining arms are twisted on the rear face of the wall. So that during the fixing process the fixing device may not be twisted relative to the wall, a support lug may be provided on a support element (fixed to the wall in the fixed state) which, for example, engages in the opening. On the support element or the retaining element, further elements, such as for example a sensor, may be fixed, said sensor being intended to be retained in a precisely predefined position. As the locking is designed in the manner of a bayonet closure, the attachment according to the invention does not require further elements such as screws for fixing the fixing device. At the same time, by pressing and twisting the retaining element a possibility may be provided for fixing elements to the wall very rapidly. 
         [0008]    The attachment according to the invention offers the advantage that the fixing device is designed to be very simple structurally. Moreover, the required components may be produced by simple production methods, such as for example a plastic injection-molding method, so that cost-effective production is also possible. At the same time, the attachment according to the invention ensures that the fixing device (and an element possibly fixed thereto), during or after the fixing process, may be retained securely in a predefined position so that subsequent slipping from the aligned position is almost excluded. 
         [0009]    In a preferred embodiment of the invention, the retaining element has a plurality of retaining arms. This provides the advantage that, on the one hand, a uniform distribution of the retaining force is applied to the rear face of the wall during fixing and thus the probability of the fixing device slipping is further reduced. On the other hand, the provision of at least two retaining arms also ensures the stability of the retaining element, so that in the event of damage to one of the retaining arms there is no risk of impairment to the functionality. 
         [0010]    Also, the at least one retaining arm may have a plurality of regions of variable thickness. This offers the advantage that, on the one hand, fixing to walls of variable wall thickness is possible and, on the other hand, variable contact force may also be exerted onto the wall. 
         [0011]    In a further embodiment of the invention, the at least one retaining arm may have a chamfer in the thickness profile. This offers an advantage when tightening the retaining arm, as said retaining arm is secured by the chamfer itself, and pulls the fixing device against the wall and fixes the fixing device there. 
         [0012]    In order to ensure a seal of the opening against dirt or liquids, the fixing device may further comprise a sealing element which is configured to seal the opening in the wall in a fluid-tight manner. 
         [0013]    According to a further embodiment, the at least one retaining arm may have a width which is configured to index an orientation of the fixing device when identifying the position of the retaining arm. This offers the advantage that the position and/or alignment of the fixing device during mounting is possible in a simple manner by identifying the characteristic retaining arm, so that an additional indexing or marking of this position may be dispensed with. 
         [0014]    According to a further embodiment of the invention, the support lug is configured to provide an aid when inserted into the opening, the support lug extending from the support element over an outer edge of the retaining arm. This provides protection of the retaining arm against damage when inserting into the opening and additionally makes the insertion of the fixing device into the opening easier for a fitter when the view of the opening is concealed. 
         [0015]    In a further embodiment of the invention, the support element or the retaining element may also have a mechanical unit, which is configured to signal to a user the twisting of the retaining element relative to the support element by a predetermined angle. This offers the advantage that it may be indicated to a fitter by simple structural elements when fixing the fixing device that the retaining arm has been rotated into a position in which a more secure hold is ensured. 
         [0016]    In a further embodiment of the invention, the support element and/or the retaining element may also have a protective element which is configured in a position of the retaining arm in the unfixed state to block the possibility of a plug connection for the contact of a sensor and, when twisting the retaining arm by a predetermined angle relative to the aforementioned position of the retaining arm, to enable the possibility of a plug connection for the contact of the sensor. This provides the possibility of informing a fitter of the fixing device that the fixing device has not yet been correctly installed. If the positioning of the plug connection for the contact of the sensor is thus prevented from being enabled, a subsequent alignment of the fixing device has to take place before further operating processes so that the secure fixing may be ensured. 
         [0017]    The support element and/or the retaining element may also have at least one locking unit which is configured to hold the retaining element in this predetermined position after reaching a predetermined position. In this manner, the fixing device may advantageously be prevented from rotating again out of the desired position which has been reached and thus a secure fixing may once again be prevented from slipping. 
         [0018]    A sensor element may also be provided with a fixing device as has been disclosed in the above embodiments. This offers the advantage that in such a configuration a particularly secure position and alignment of the sensor element may be ensured and thus the functionality of the sensor element is ensured in the best possible manner. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention is described in more detail hereinafter by way of example with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  shows two views of hole patterns of openings in the wall in which the fixing device may be inserted and fixed; 
           [0021]      FIG. 2  shows a perspective view of an exemplary embodiment of the present invention; 
           [0022]      FIG. 3  shows a perspective view of the exemplary embodiment according to  FIG. 2  of the present invention when fitted in a support; 
           [0023]      FIG. 4  shows a further perspective view of the exemplary embodiment shown in  FIG. 3  of the present invention, a detail being reproduced in sectional view; 
           [0024]      FIG. 5  shows views of an exemplary embodiment of the present invention from different perspectives; 
           [0025]      FIG. 6  shows views of the exemplary embodiment of the present invention shown in  FIG. 5 , the dimensioning having been provided for a possible implementation of the exemplary embodiment; 
           [0026]      FIG. 7  shows a representation of a cross-sectional view of the exemplary embodiment shown in  FIG. 5  or  FIG. 6 ; 
           [0027]      FIG. 8  shows perspective views of exemplary embodiments of the invention, the blocking elements preventing twisting of the fixing device after reaching the predefined position; 
           [0028]      FIG. 9  shows perspective views of exemplary embodiments of the invention, which ensure installation aids for rapid and secure installation of the fixing device according to the invention in the opening in the wall; and 
           [0029]      FIG. 10  shows a flow diagram of an exemplary embodiment of the invention as a method. 
       
    
    
       [0030]    Dimensions and sizes which may have been provided are only given by way of example, so that the invention is not limited to these dimensions and sizes. The same or similar elements are provided with the same or similar reference numerals. The figures of the drawings, the description thereof and the claims also contain many features in combination. It is clear to a person skilled in the art that these features may also be considered individually or they may be combined to form further combinations not specifically described here. 
       DETAILED DESCRIPTION 
       [0031]    It is the object of the invention, in particular, to design the layout of a sensor and/or a fixing device so that the mounting of the fixing device which may carry a sensor is possible without additional fixing means. At the same time, the mounting is intended to be simple and secure in order to prevent and/or make difficult faulty mechanical installation as far as possible. Furthermore, it is an object of the invention to design the fixing device and/or a sensor, so that it may be used universally and, for example, may be mounted on door supports of variable material thickness. 
         [0032]    The invention is further described in detail using the example of an airbag pressure sensor. The invention may be transferred, however, to other types of sensor and applications. The airbag pressure sensor is designed so that in use the sensor is installed in the side doors of the vehicles, in order to detect the deformation of the doors in the event of a side impact. 
         [0033]    The invention is based substantially on the use and/or development of the concept of a bayonet fixing for sensors. The fixing takes place, in particular, by means of a rotational movement of the fixing device (and/or of the sensor) or a part fixed to the fixing device (and/or to the sensor) relative to the door support or relative to a further support and/or a wall with a corresponding geometry. In the support and/or the wall, only one hole pattern should be provided which permits a “bayonet fixing” and if a sealing function of the sensor is desired relative to the support, a sufficiently planar, defined surface is provided around the fixing hole. 
         [0034]    The fixing device and/or the sensor thus consists, for example, of two components which are rotatable relative to one another, one component being rotated during mounting relative to the support, the other component however being securely fixed in the support and correspondingly not rotated during mounting. 
         [0035]    The advantages of the attachment according to the invention may be summarized as follows: 
         [0036]    The mounting of the sensor is possible without additional fixing means. The mounting of the sensor may be possible in a simple manner on supports and/or walls of different thicknesses. Devices may be attached to the sensor which permit easy threading-through into the hole pattern and simple and secure mounting. These are mechanical threading aids (chamfers), mechanical indexing for precise installation (protection against twisted installation), mechanical fixing and locking as well as devices which permit the monitoring of the installation process by optical, haptic and/or acoustic communication to the operator. The mounting of the sensor takes place, for example, by means of a bayonet closure-type locking element; as a result, the retaining force is applied via an inflexible and robust mechanical device. The sensor may be designed so that the contact of the plug is only possible if the sensor has been correctly mounted in the support with a sufficient angle of rotation. Provided the rotational movement has not been fully completed, the plug is mechanically locked. At the same time, it is possible to design the layout so that when the mating plug is positioned on the sensor, it is not possible to rotate the sensor out of the support as it is mechanically locked. A non-rotating lock may be attached to the sensor in a single or multiple embodiment which does not permit the two components of the sensor to rotate counter to one another, provided the sensor is not pressed onto the support. Thus a faulty installation and/or a release of the plug by twisting the sensor components in any position is made difficult and/or avoided. 
         [0037]    The essential advantage of the invention is that such a fixing device and/or a sensor thus designed may be mounted securely and simply without additional aids. 
         [0038]    The operating principle is shown in more detail by way of example in the accompanying sketches and drawings of the figures. 
         [0039]      FIG. 1  firstly shows two views of hole patterns of openings in a support and/or a wall, the fixing device according to the invention being able to be inserted into these holes  100  of the wall  105 . The holes  100  are such that they have sides regions  110  of different widths around the actual central hole  100 , through which side regions the retaining arms of the fixing device may be guided. The side regions  110  are thus of variable width, so that by means of the width of the retaining arm an indexing of the position of the fixing device is possible when inserting into the hole  100  in the wall  105 . 
         [0040]    In  FIG. 2 , an exemplary embodiment of the present invention is shown as a perspective view. The fixing device  200  which, for example, may itself be a support holder of a sensor or the sensor itself, comprises a support element  210  for supporting on the support or the wall, the support element comprising a support lug  220 . The fixing device  200  further comprises a retaining element  230  with retaining arms  240 . The retaining element  230  is rotatably arranged relative to the support element  210 , so that a rotational axis of the retaining element  230  passes through the support element  210 . 
         [0041]    In this exemplary embodiment the support lugs  220  are provided as threading aids for mounting the fixing device  200  in the openings  100  in the wall  105 , so that they cover an outermost region of the retaining arms  240  and thus not only protect said retaining arms during insertion into the opening but also provides guidance during mounting, when the opening in the wall is concealed, for example by the support element  210 . Also the support lug  220  and/or the two support lugs  220  may be of variable width, similar to the two retaining arms  240 , so that the indexing of the position of the fixing device  200  is also possible by means of the support lug  220 . 
         [0042]    The retaining arms  240  may thus be designed according to the different widths of the side regions  110  of the holes  100 , in order to ensure indexing of the position or alignment of the fixing device during installation. From  FIG. 2  it is also visible that the retaining arms  240  have different partial regions, of variable thickness, in order to be able to engage easily in walls of different wall thicknesses without different fixing devices possibly being required therefor. Also in  FIG. 2 , a sealing element  250  is visible which is arranged in an annular manner about an edge of the support element  210 , and may seal the opening and/or the hole  100  in a fluid-tight manner against liquids or gases. Moreover, in  FIG. 2  a protective element  260  is also visible, which may be fixed to the support element  210  and/or to the retaining element  230  (not visible in the view of  FIG. 2 ). The protective element  260  is designed so that a plug connection  270  is enabled when the retaining element is twisted relative to the support element  210 , whereby the possibility of a plug connection for a sensor attached to the fixing device is only possible after correct twisting and thus locking of the retaining element  230 . 
         [0043]    In order to be able to compensate for tolerances in the support/wall thicknesses and unevenness, two compensation mechanisms may be used. Firstly, the bayonet and/or retaining arm  240  may be of a multi-stepped design, as already shown in  FIG. 2 . In connection with a correspondingly adapted internal radius  100  of the hole pattern, the contact of the fixing device  200  and/or of the sensor or the possible wall thickness (support thickness) may thus be varied. This is visible from  FIG. 1  and  FIG. 7  described below. Secondly, the seal  250  or a compressible compensating element may be inserted between the fixing device/sensor  200  and wall/support  105  which with smaller variations in the support thickness or unevenness in the support permits compensation to a limited extent. 
         [0044]    In  FIG. 3  the installation of an exemplary embodiment of the present invention is shown. In this case, the support lugs  220 , which are designed in the present example as insertion aids and/or threading aids, are inserted together with the retaining arms  240  of the retaining element  230  into the hole  100  and/or the side regions  110  in the wall  105 . In  FIG. 3 , the state after insertion from the rear face of the wall  105  is shown. 
         [0045]    In  FIG. 4  a side view of the fixing device after the introduction and/or insertion of the retaining element  230  and the support lug  220  into the opening  100  of the wall  105  is visible. In this case, the arrangement of the protective element on the support element  210  is also visible, so that when twisting the retaining element  230  the protective element  260  permits the possibility of the plug connection  270 . Alternatively, the support element  210  may also be twisted relative to the retaining element  230 ; it only has to be ensured that retaining arms  240  on the rear face of the wall  105  are twisted and a locking of the fixing device  200  in the wall  105  results. 
         [0046]    In  FIG. 5 , such an enabling of the possibility of the plug connection  270  with an external plug  500  is shown, in the left-hand views of  FIG. 5  the arrangement being shown before the fixing in the wall and/or before the twisting of the retaining element  230  relative to the support element  210  in side view (lower view) and plan view (upper view) and in the right-hand view of  FIG. 5  an arrangement being shown after correctly twisting the retaining element  210  relative to the support element  230 . Thus it is also visible that the possibility of the plug connection  270  is only enabled after rotating about a predetermined angle, as only after twisting about this predetermined angle does the protective element  260  permit the possibility of the plug connection  270  for positioning a plug  500 . 
         [0047]      FIG. 6  shows a practical embodiment with the dimensioning of the fixing device and/or a sensor, as is shown in  FIG. 5 . 
         [0048]      FIG. 7  shows a schematic cross-sectional view of the fixing device according to the exemplary embodiment, as is also shown in  FIGS. 2 to 6 . 
         [0049]      FIG. 8  shows possible blocking elements  800  in the fixing device  200  in different enlarged perspective views. The blocking element  800  shown in each case is provided to avoid a twisting of the fixing device  200  relative to the plug locking  260  without correct installation. The blocking element  800  may thus be configured such that it is engaged when reaching the predefined end position when twisting the support element  210  or the retaining element  210  and thus activates a locking function, which prevents turning back the retaining element  230  or the support element  210 . 
         [0050]    In  FIG. 9  in different perspective views possible installation aids are shown graphically which, for example, show guides or latching  900  on a defined end stop  910 . 
         [0051]    In  FIG. 10  a flow diagram of an exemplary embodiment of the present invention is shown further as a method. The method  1000  is provided for fastening a fixing device  200  for fixing an element in an opening  100  of a wall  105 , the fixing device  200  comprising a support element  210  with at least one support lug  220  and a retaining element  230  with at least one retaining arm  240  for fixing the fixing device to the wall, the retaining element  230  being arranged in a rotatable manner through the support element  210  for fixing the fixing device  200  relative to the support element  210 , and the support lug  220  being configured to block a rotation of the support element  210  in the wall  105 . The method  1000  comprises a first step of insertion  1010  of the support lug and of the retaining element in the opening in the wall and a second step  1020  of rotation of the retaining arm relative to the support element in order to lock the fixing device to the wall, the support lug blocking a rotation of the support element. 
         [0052]    In summary it may be noted that a sensor and/or a fixing device for a sensor, as already indicated above, may consist of two or more parts which may be rotated relative to one another. In the example set forth, the sensor is designed so that the sensor  200  is provided with a so-called sealing plate  250  which, for example, may be simply positioned on the sensor  200  (see also  FIGS. 5 and 8 ). The sealing plate  250  may have a fixing crown, which in the delivery state of the sensor  200  is adjacent to the bayonet arms  240  fixed to the sensor (see  FIGS. 2 ,  3 ,  4 ,  8  and  9 ). When threading through into the hole  100 , the fixing crown  220  and the bayonet arms  240  are positioned in the support  105  through the hole  100  and/or  110 . Then the sensor which, for example, is fixed to the retaining element  230 , is rotated relative to the sealing plate  250  (which, for example, is arranged on the support element  210 ) as well as the support  105  by a specific angle. The sealing plate  250  thus remains, due to the fixing crown  220 , securely fixed in the support  105  and does not twist. In this case, the fixing crown forms the support lug  220 . This permits the use of flexible seals or compressible compensating elements and avoids during installation shear forces acting on the flexible structures which are possibly not very robust. When twisting the sensor, the bayonet arms  240  rotate over the support material around the internal radius and thus locks the sensor in the support. By means of chamfers, the arms  240  may thus be designed so that they are pulled against the support when fixing the sensor, which is thus fixed more securely. In the example set forth, when fixing the sealing plate, the bayonet on the sensor is clamped between the support and sensor. 
         [0053]    Threading aids/chamfers  220  are attached to the fixing crown and/or to the support element  210 , said threading aids/chamfers permitting the mounting of the sensor without the bayonet fixing or the hole being visible in the support (this may be concealed visually by the sensor). By mechanical devices, (for example a ball track or the like) it may be avoided that the sensor is able to be twisted in the incorrect direction. Moreover, the overtwisting of the sensor may be avoided via a similar device or the same device. In each case, the fixing crown  220  may serve as an anchor relative to the support and/or the wall  105 . 
         [0054]    In order to simplify the installation of the sensor further and to allow it to be monitored, mechanical devices may be present on the sensor which inform the operator in an optical, haptic and/or acoustic manner whether and/or that the sensor has been correctly twisted into the final position. Possibly, clip devices may also be produced so that repeated mounting of the sensor is possible. 
         [0055]    On the sensor and/or on the sealing ring a mechanical plug lock may be provided which prevents the mating plug from being able to be attached to the sensor, provided the sensor has not been sufficiently twisted relative to the support and/or provided the sensor is not in the final position (see also  FIGS. 5 and 7 ). 
         [0056]    This device may be further designed so that the sensor may only be released from the support when the counter plug  500  has been removed. The counter plug  500  and the electrical contact thus gain a possible monitoring function: whether the electrical contact is present, the sensor has been mounted and/or the sensor has not been dismantled. 
         [0057]    In order to prevent mistreatment as far as possible, in the sensor a lock may be attached to prevent twisting of the sensor relative to the plug lock/sealing plate. This may be implemented by a simple locking hook  800  as is shown in  FIG. 8 . The locking hook  800  prevents a rotation of the sensor relative to the sealing plate and vice-versa. Only when the locking hook is released by contact and/or by pressing the sensor against the support is a rotation of the sensor relative to the sealing plate and/or the plug lock and thus the unlocking of the plug lock possible. When a plurality of said locking hooks are produced, deliberate mistreatment is made more difficult. It is an object of the invention to permit the rotation of the sensor and the unlocking of the plug only in the target position in the support and/or to make different ways of mounting or unlocking the plug as difficult as possible.