Abstract:
A device for raising a body component of a motor vehicle, especially an engine hood, from a starting position into a receiving position can be returned to an operative state by opening and closing the body component after actuation. A method to operate such a device has the following steps: The device is activated, with the result that the body component is raised; it is recognized that the body component can be lowered again, whereupon a deactivation mechanism is actuated, with the result that the body component is lowered; the body component is opened and closed again, with the result that the device is returned to an operative state. Preferably, the device has a spring that relaxes when the body component is raised and that is tensioned when the body component is opened and closed.

Description:
[0001]     The present invention relates to a device to raise a body component of a motor vehicle from a starting position into a receiving position as well as to a method to operate such a device.  
       BACKGROUND OF THE INVENTION  
       [0002]     Such devices (see, for example, DE 199 46 408) are in use in actual practice and serve primarily to raise the engine hood so as to provide better protection for a pedestrian or cyclist in case of a collision with a vehicle. After being activated by a suitable sensor system, the engine hood is raised so as to provide additional deformation space above the engine block.  
         [0003]     Various types of such devices are known which differ especially in terms of the drive means employed. Thus, in addition to pyrotechnical systems, one can also use pneumatic or electric motor systems as well as combinations of various systems. Since not every actuation of the device actually involves a collision and thus a deformation of the engine hood, there is a need for a device that can be returned to its starting position and can thus be re-used.  
         [0004]     Here, however, pyrotechnical systems have the drawback that, in any case, the vehicle owner incurs costs in order to reactivate the raising device, even if it was actuated erroneously, since in that case, new pyrotechnical propellant charges, for example, have to be installed in the vehicle.  
         [0005]     Pneumatic systems, in turn, require the installation of a compressed air system or small compressor inside the vehicle and are consequently quite complex.  
         [0006]     Electric motor systems likewise do not lend themselves for use in a raising device since the response times of electric motors are far too slow; moreover, these systems are relatively prone to malfunction and call for a great deal of maintenance.  
         [0007]     Mechanical spring devices that combine the advantages of a short response time, low tendency to malfunction and low production costs exist so far only as pure raising devices that, after an erroneous actuation, either have to be returned to their starting position by a complicated manual procedure or else they are combined with one of the above-mentioned systems that then serves to reset the raised body component, and this, in turn, entails the already mentioned drawbacks.  
         [0008]     Therefore, the objective of the present invention is to provide a raising device that can be returned to an operative state quickly, simply and without incurring any costs whenever it has been erroneously actuated.  
       BRIEF DESCRIPTION OF THE INVENTION  
       [0009]     According to the invention, with a device of the type mentioned above, it is provided that the device, once it has been actuated, can be returned to an operative state by opening and closing the body component. Such a method for operating such a device calls for the following steps: first of all, the device is activated, with the result that the body component is raised. Once it has been recognized that the body component can be lowered again, a deactivation mechanism is actuated, with the result that the body component is lowered. Subsequently, the body component is opened and closed again, with the result that the device is returned to an operative state.  
         [0010]     In this manner, for example, after an erroneous actuation, the vehicle driver himself is able to quickly and simply return the device according to the invention to an operative state.  
         [0011]     Preferably, the device has a raising fixture which is intended to be coupled to a body component that is to be raised, it also has an energy accumulator that is coupled to the raising fixture, a raising mechanism that can release the raising fixture, and a resetting mechanism by means of which the raising fixture can be returned to the starting position after having been activated. Thus, by activating the resetting mechanism, for example, in response to a sensor signal that is emitted immediately after the absence of a collision, any obstruction of the driver&#39;s view that might occur due to a raised front engine hood can quickly be eliminated.  
         [0012]     In a preferred embodiment, the raising mechanism has a raising ratchet that can be actuated by a control element, thereby ensuring a rapid and reliable raising of the body component.  
         [0013]     By the same token, the resetting mechanism can have a resetting ratchet that can likewise be actuated by a control element, which correspondingly allows a rapid lowering of the body component.  
         [0014]     Preferably, the resetting mechanism interacts with a movable abutment which makes it possible to utilize gravity during the resetting process.  
         [0015]     Since the energy accumulator preferably rests on the abutment, the energy accumulator can also be utilized to reset the body component.  
         [0016]     The raising mechanism and the resetting mechanism are preferably arranged in such a way that the raising mechanism can again lock the raising fixture after an activation once the resetting mechanism has released the abutment. This translates into a simple and effective system that ensures a fast and reliable lowering of the body component.  
         [0017]     Preferably, the body component is coupled to the abutment via a tie rod in such a way that, when the body component opens, the abutment can be adjusted against the action of the energy accumulator until it can be locked by the resetting mechanism. This results in an effective and easily performed restoration of the device to an operative state, which dispenses with the need for a dedicated reactivation mechanism.  
         [0018]     According to an embodiment, the abutment is translationally adjustable, with the result that gravity can be utilized to reset the body component in an especially advantageous way.  
         [0019]     Another embodiment of the device according to the invention comprises a rotatorily adjustable abutment that can be accommodated in the vehicle in a space-saving manner.  
         [0020]     An inexpensive pressure spring can be used as the energy accumulator which, as a purely mechanical system, is particularly impervious to malfunction and is thus largely maintenance-free.  
         [0021]     Furthermore, the use of a torsion spring as the energy accumulator offers the advantage of a compact design.  
         [0022]     Therefore, the device advantageously has a spring that relaxes when the body component is raised and that is tensioned when the body component is opened and closed, which accounts for a simple and effective reversible mechanism.  
         [0023]     In a preferred embodiment, the raising fixture is coupled to an adjusting lever which, in turn, is coupled to the energy accumulator. The use of such a lever offers the possibility of achieving a ratio between the opening path of the body component and the requisite force that is optimal for the application purpose in question.  
         [0024]     According to a refinement of the invention, after the device has been activated, by opening the body component against the action of the energy accumulator, the adjusting lever can be pivoted until it can be locked in an intermediate position by the resetting mechanism. In this manner, when the body component is opened, less force is needed than if the starting position of the device had already been restored.  
         [0025]     Preferably, the adjusting lever can be moved out of the intermediate position by closing the body component against the action of the energy accumulator and into the starting position, with the result that the energy accumulator is further pre-tensioned. Thus, during the final tensioning of the energy accumulator, gravity can be utilized in an advantageous manner.  
         [0026]     The body component can be coupled to the adjusting lever by a coupling rod which, when the body component is completely opened and subsequently closed, passes through a dead center so that the adjusting lever can be driven in the same direction like a crank gear during the opening and closing of the body component. In this manner, the forces applied for opening and closing can likewise be used to tension the energy accumulator.  
         [0027]     The body component to be raised is preferably an engine hood, which allows the use of the device for the above-mentioned protection of a cyclist or pedestrian in case of a collision. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0028]     Additional features and advantages of the invention ensue from the following description of several preferred embodiments with reference to the companying drawings. The drawings show the following:  
         [0029]      FIG. 1   a  schematic side view of the front part of a vehicle;  
         [0030]      FIG. 2   a  side view of a first embodiment of a device according to the invention in an operative starting position;  
         [0031]      FIG. 3   a  side view of the device from  FIG. 2  in an extended receiving position;  
         [0032]      FIG. 4   a  side view of the device from  FIG. 2  in a lowered but not yet operative state;  
         [0033]      FIG. 5   a  side view of the device from  FIG. 2  in a position that corresponds to a partially opened body component;  
         [0034]      FIG. 6   a  side view of the device from  FIG. 2  in a position with a completely opened body component, whereby the device is once again in the operative state;  
         [0035]      FIG. 7   a  side view of a variant of the device from  FIG. 2  in an operative starting position;  
         [0036]      FIG. 8   a  side view of the device from  FIG. 7  in an extended receiving position;  
         [0037]      FIG. 9   a  side view of a second embodiment of a device according to the invention in an operative state in a starting position;  
         [0038]      FIG. 10   a  side view of the device from  FIG. 9  in a receiving position;  
         [0039]      FIG. 11   a  side view of the device from  FIG. 9  after the lowering of the body component;  
         [0040]      FIG. 12   a  side view of the device from  FIG. 9  in an intermediate position that corresponds to the opening of the body component;  
         [0041]      FIG. 13   a  side view of the device from  FIG. 9  in a position that corresponds to the closing of the body component;  
         [0042]      FIG. 14   a  side view of a third embodiment of a device according to the invention in an operative starting position;  
         [0043]      FIG. 15   a  side view of the device from  FIG. 14  in an extended receiving position;  
         [0044]      FIG. 16   a  side view of the device from  FIG. 14  in a position after the lowering of the body component;  
         [0045]      FIG. 17   a  side view of the device from  FIG. 14  in a position that corresponds to a partially opened body component; and  
         [0046]      FIG. 18   a  side view of the device from  FIG. 14  in an operative state with a completely opened body component. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0047]      FIG. 1  shows a vehicle  1  that is equipped with a device according to the invention for raising a body component, here, an engine hood  2 . The device is only schematically indicated and designated with the reference numeral  10 . The vehicle  1  is normally driven with a closed engine hood  2  (solid line) that covers the engine compartment containing, among other things, an engine block  4 . In case of a collision, for example, with a pedestrian, which can be detected, for instance, by means of a sensor  8  attached to the bumper  6  of the vehicle  1 , the device  10 —in response to a signal generated by the sensor  8 —raises the engine hood  2  into a receiving position (shown by a broken line) in order to provide additional deformation space for the pedestrian by enlarging the distance between the engine hood  2  and the engine block  4 .  
         [0048]     A first embodiment of a raising device  10  according to  FIG. 2  comprises a raising fixture  12  which is intended to be coupled to the body component  2  that is to be raised, as well as a raising lever  14 , which—in the starting position of the device  10  shown in  FIG. 2 —is arranged parallel below the raising fixture  12  and is connected thereto at a point P 1  so as to pivot. The raising lever  14  has a slot  16  by means of which it is movably connected to an attachment fixture  20  at a point P 2 , whereby the attachment fixture  20  is to be permanently mounted on the car body. Moreover, a hook  18  is mounted on the raising lever  14  in such a way that the hook  18  can be grasped by a raising ratchet  22  mounted on a ratchet fixture  24  that can pivot at a point P 4 . The ratchet fixture  24 , in turn, is rigidly connected to the car body. Together with an actuating member (not shown), the raising ratchet  22  forms a raising mechanism that can release the raising fixture  12  in case of activation.  
         [0049]     Moreover, on the ratchet fixture  24 , there is a resetting ratchet  32  that is connected to the ratchet fixture  24  at a point P 5  so as to pivot. The resetting ratchet  32  engages a movable abutment  28  at a point P 6  on which an energy accumulator  26  in the form of a pressure spring rests that is also connected to the raising lever  14  at a point P 3  so as to pivot. The ratchet fixture  24  has a slot  34  into which a section of the movable abutment  28  engages and in which the latter can slide after the resetting ratchet  32  has been opened. An auxiliary spring  30  is provided that rests with one of its ends on the ratchet fixture  24  and with its other end on the movable abutment  28 . Both springs  26 ,  30  are pre-tensioned in the starting position shown in  FIG. 2 . Moreover, the raising device  10  has a tie rod in the form of a holding cable  36  that is connected to the movable abutment  28  at a point P 6  so as to pivot, and to the raising fixture  12  at a point P 7  so as to pivot.  
         [0050]     In response to a signal of the sensor  8 , which indicates a collision with a pedestrian, the actuating member (not shown) rotates the raising ratchet  22  around the point P 4 , with the result that the hook  18  and thus the raising lever  14  are released so that, due to the pre-tensioning of the pressure spring  26 , the raising lever  14 , and with it the raising fixture  12 , as well as the coupled body component  2  of the vehicle, move abruptly upwards and the device  10  assumes the position shown in  FIG. 3 . In this manner, for example, an engine hood  2  coupled to the raising fixture  12 , can be raised to the receiving position within a very short period of time. The final phase of the movement is influenced by the holding cable  36  as well as by the slot  16 , which serve as a limit stop, in a manner of speaking, when the engine hood  2  is raised.  
         [0051]     If the anticipated collision does not occur, in order to eliminate any obstruction of the driver&#39;s field of vision as quickly as possible, it is desirable to return the engine hood  2  to a closed position. For this purpose, there is a resetting mechanism that comprises the resetting ratchet  32  which is pivoted by an actuating member (not shown) around the point P 5  in such a way that it releases the movable abutment  28 , with the result that the abutment  28  moves downwards inside the slot  34  and, during this movement, due to the coupling via the spring  26 , pulls the raising lever  14  and thus the raising fixture  12  down into a lowered position of the body component  2 . The pre-tensioned auxiliary spring  30  has the function of supporting the weight that is exerted on the engine hood  2  and on the abutment  28 . After the movable abutment  28  has been released by the resetting mechanism, the raising ratchet  22  engages in the hook  18  again, with the result that the raising fixture  12  and thus the engine hood  2  are locked, as can be seen in  FIG. 4 .  
         [0052]     In order to subsequently return the device  10  to an operative state, the engine hood  2  is opened, as shown in  FIGS. 5 and 6 . Here, the raising fixture  12  coupled to the engine hood  2  is rotated counterclockwise around the now stationary point P 1 , a process in which it pulls the movable abutment  28  in the slot  34  via the holding cable  36  upwards against the action of the springs  26  and  30  until the abutment  28  latches in the resetting ratchet  32  again. Thus, the device  10 , after the engine hood  2  has been closed, is once again in the operative starting position shown in  FIG. 2 .  
         [0053]      FIGS. 7 and 8  show the operative starting position or the receiving position of a variant of the first embodiment of the device  10 , in which the slot  16  in the raising lever  14  is replaced by a second lever  15  that is connected to the raising lever  14  at the point P 2  so as to pivot and is mounted on the vehicle body at a point P 8  so as to pivot. Since this variant is otherwise identical to the embodiment shown in FIGS.  2  to  6 , this variant will not be elaborated upon further here.  
         [0054]     FIGS.  9  to  13  show a second embodiment of a device  10  according to the invention, whereby the same components are designated with the same reference numerals so that merely the differences of the second embodiment as compared to the first embodiment will be discussed below. Instead of the pressure spring  26 , the device  10  according to the second embodiment has a torsion spring  26  as the energy accumulator that is connected at one of its ends to an adjusting lever  40  at a point P 10  and at its other end to the body of the vehicle (indicated by abutment  28 ′). The adjusting lever  40  has a stop  29  that is connected in one piece to said adjusting lever  40  and said stop  29  can engage in a resetting ratchet  32  and is mounted on the vehicle body at a point P 9  so as to rotate. Furthermore, the adjusting lever  40  has a slot  42  into which a coupling rod  38  engages at a point P 11  so as to slide, whereby the coupling rod  38  is connected at one of its ends to the raising fixture  12  at a point P 12  so as to pivot.  
         [0055]     In the operative starting position of the device  10  shown in  FIG. 9 , the torsion spring  26  is strongly pre-tensioned. When the raising mechanism is now actuated and the raising ratchet  22  is pivoted around the point P 4 , it releases the hook  18 , with the result that the raising fixture  12 —due to the pre-tensioning of the torsion spring  26  and due to the fact that this torsion spring  26  is coupled to the raising fixture  12  via the coupling rod  38 —moves abruptly upwards and thus moves an engine hood  2  connected thereto into a receiving position. Here, the coupling rod  38  also serves as a limit stop.  
         [0056]     This receiving position shown in  FIG. 10  is characterized in that the stop  29  engages the resetting ratchet  32  and thus prevents any further movement due to the remaining pre-tensioning of the torsion paring  26  (clockwise) whereby, unlike the first embodiment, the resetting ratchet  32  was not yet engaged with the stop  29  in the starting position shown in  FIG. 9 .  
         [0057]     From the receiving position, the device  10  can be moved into the position with the lowered engine hood  2  shown in  FIG. 11  in that the resetting ratchet  32  is pivoted around the point P 5 , with the result that it releases the limit stop  29  and the torsion spring  26  that is still under pre-tension pivots the adjusting lever  40  further around the point P 9 . In this process, the adjusting lever  40 —via the coupling rod  38 —pulls the raising fixture  12  and the raising lever  14  coupled thereto downwards into a lowered position in which the raising ratchet  22  can engage the hook  18  again and thus can lock the raising fixture  12  in the lowered position. Therefore, the raising as well as the lowering of the engine hood  2  are achieved in that the adjusting lever  40  is driven both times in the same direction, namely, clockwise in the embodiment shown.  
         [0058]     In order to now pre-tension the torsion spring  26  and thus return the device  10  to an operative state, as is shown in  FIG. 12 , the engine hood  2  is first opened completely, with the result that the adjusting lever  40  is rotated against the action of the torsion spring  26  counterclockwise until it latches with the limit stop  29  in the intermediate position on the resetting ratchet  32  as shown in  FIG. 12 .  
         [0059]     From this intermediate position, the device  10  is returned to the operative state by a subsequent closing of the engine hood  2 , as shown in  FIG. 13 , whereby the adjusting lever  40  is rotated further counterclockwise and against the action of the torsion spring  26  around the point P 9  until, after the engine hood has been completely closed, it is once again in the starting position with the pre-tensioned torsion spring  26 , as shown in  FIG. 9 .  
         [0060]     When the engine hood  2  is opened and closed, the adjusting lever  40  is only driven in one direction, namely, counterclockwise, like a crank gear. In doing so, it passes through a dead center that is reached when the engine hood is in the maximally opened position shown in  FIG. 12  and when the coupling rod  38  engages the outer end of the slot  42 . In this manner, a displacement of the line of action of the force transferred to the adjusting lever  40  is achieved, thus making it possible to use the opening as well as the closing motion of the engine hood  2  to tension the torsion spring  26 .  
         [0061]     FIGS.  14  to  18  show a third embodiment of a device  10  according to the invention that, as an energy accumulator, uses a torsion spring  26  that engages at one of its ends with a movable adjusting lever  40  and at its other end with a movable abutment  28 , whereby the abutment  28  and the adjusting lever  40  are mounted on the car body so as to pivot at a shared point P 9  and they can pivot independent of each other around this point.  
         [0062]     In the operative starting position shown in  FIG. 14 , the torsion spring  26  is under pre-tension and the abutment  28  is held in position by a resetting ratchet  32 . Once again, there is a holding cable  36  that is attached at one of its ends to the abutment  28  at a point P 6  and at its other end to the raising fixture  12  at a point P 7 .  
         [0063]     The raising lever  14  is connected to the adjusting lever  40  at a point P 12  so as to pivot and, after the release of the hook  18  by the raising ratchet  22 , due to the pre-tensioning of the torsion spring  26 , moves together with the adjusting lever  40  counterclockwise and upwards, with the result that the device  10  is returned to the receiving position shown in  FIG. 15 . The tie rod  36 , like the raising lever  14 , which is present here in an angled form, serves as the limit stop for the hood raising movement.  
         [0064]     In order to return the engine hood  2  to a lowered position, the resetting ratchet  32  is pivoted around a point P 5 , thus releasing the abutment  28 , which subsequently pivots clockwise by about 90° downwards due to gravity and to a possible residual tension of the torsion spring  26 , whereby said abutment lowers the raising fixture  12  and the raising lever  14  coupled thereto via the tie rod  36 . Then the hook  18  can once again be engaged by the raising ratchet  22 , so that the engine hood  2  is locked in the lowered position ( FIG. 16 ).  
         [0065]      FIGS. 17 and 18  show how the device  10  is returned to an operative state after being activated. For this purpose, the engine hood  2  is opened, with the result that the raising fixture  12  rotates counterclockwise around the point P 1  and, due to the connection by the tie rod  36 , rotates the abutment  28  by about 90° counter-clockwise, so that, in the maximally opened position of the engine hood  2  shown in  FIG. 18 , the resetting ratchet  32  engages the abutment  28  again and thus secures the device  10  against the action of the torsion spring  26  in an operative state that is reached by the subsequent closing of the engine hood  2 .