Abstract:
A pedal arrangement for a motor vehicle includes a pedal arm connected to the vehicle structure via a first pivotal joint connection and connected to a force transmitting element via a second pivotal joint connection. The pedal arrangement further includes a pyrotechnically driven release arrangement. The release arrangement is adapted to perform a release movement in order to release the second pivotal joint connection upon being driven in response to a corresponding activation signal. The release movement of the release arrangement is based on a translational movement essentially along the pedal arm.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit and priority of DE 10 2009 059000.5, filed 17 Dec. 2009. The entire disclosure of the above application is incorporated herein by reference. 
       FIELD 
       [0002]    The present disclosure relates to a pedal arrangement for a motor vehicle, comprising a pedal arm connected to the vehicle structure via a first pivotal joint connection and connected to a force transmitting element via a second pivotal joint connection, said pedal arrangement further comprising a pyrotechnically driven release arrangement, wherein said release arrangement is adapted to perform a release movement in order to release said second pivotal joint connection upon being driven in response to a corresponding activation signal. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    Due to the release of the connection between the force transmitting element and the pedal arm, the pedal can move freely away from the driver which reduces the injury risk of the driver in the foot region in an accident. 
         [0005]    DE 195 15 852 C2 discloses a pedal arrangement according to the preamble of claim  1  with a swivelling part pivotably connected in the first pivotal joint and comprising a reception for an end of the force transmitting element. Upon activation the swivelling part is forced to swivel around the first pivotal point, thereby removing the reception and releasing the connection between the force transmitting element and the pedal arm. 
         [0006]    EP 0 877 685 B1 discloses another pedal arrangement according to the preamble of claim  1  with a pyrotechnically driven rotatable plate mounted between the force transmitting rod and the pedal arm. Ignition of a powder charge causes the plate to rotate, whereby tongues of the plate push the force transmitting rod axially of a shaft and thereby release the force transmitting rod from the pedal arm. 
       SUMMARY 
       [0007]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0008]    The object of the invention is to provide a pedal arm arrangement with a simple, robust and reliable release arrangement. 
         [0009]    The invention solves this object with the features of the independent claims. The translational movement of the release arrangement essentially along the pedal arm is mainly perpendicular to the vehicle movement direction, so that disturbances caused by the enormous forces acting in the vehicle movement direction can be reduced and the reliability can be significantly enhanced. Furthermore, the usually linear movement of the pyrotechnical actuator can be particularly easily transformed into a translational movement of the release arrangement. 
         [0010]    The release movement being based on a translational movement means in particular that the part in the release arrangement directly acting on the second pivot joint is performing a translational movement. Preferably all moving parts of the release arrangement between the pyrotechnical actuator and the second pivot joint are based on a translational movement, leading to a particularly simple release arrangement. 
         [0011]    In a preferred embodiment the release arrangement performs a translational movement of an end of said force transmitting element. This allows a very robust design of the release arrangement. Furthermore, the number of parts can be reduced. 
         [0012]    Preferably the pedal arm comprises an aperture for allowing the force transmitting element to penetrate through upon release. In this case no lateral movement between the force transmitting element and the pedal arm is required to allow free movement of the pedal arm. However, an aperture in the pedal arm for the force transmitting element is not strictly required. Alternatively means for guiding the force transmitting element laterally relative to the pedal arm may be provided. 
         [0013]    In another embodiment the release arrangement may comprise a translationally movable sliding element, in particular a part of a cup provided in said pedal arm for receiving an end of said force transmitting element, which sliding element is preferably movable from a blocking position in which it is arranged to block an aperture in the pedal arm, to a release position in which it is arranged to uncover the aperture in the pedal arm. 
         [0014]    Preferably the pedal arrangement comprises a force limiting element arranged to act between said pedal arm and said force transmitting element, in order to avoid a high acceleration and an unwanted rebound of the pedal after release. 
         [0015]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0016]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0017]      FIGS. 1A-1C  show a pedal arrangement according to a preferred embodiment of the invention in different states; 
           [0018]      FIGS. 2A-2C  show a pedal arrangement according to another embodiment of the invention in different states; 
           [0019]      FIGS. 3A-3C  show a perspective view on a release arrangement for a pedal arrangement according to a further embodiment of the invention in different states; 
           [0020]      FIGS. 4A-4C  show the release arrangement of  FIGS. 3A-3C  in a sectional view; 
           [0021]      FIGS. 5A-5C  show a force limiting element for a release arrangement according to the invention; 
           [0022]      FIGS. 6A ,  6 B show another force limiting element for a release arrangement according to the invention; and 
           [0023]      FIGS. 7A ,  7 B show a pyrotechnical activator for a release arrangement according to the invention. 
       
    
    
       [0024]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0025]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0026]    The pedal arrangement  10 , in particularly a foot pedal in a motor vehicle, like brake pedal or clutch pedal, comprises a pedal arm  11  which is pivotably connected to the vehicle structure via a first pivotal joint  12 . A force exerted by the driver to the pedal arm  11  is transmitted to a brake booster  13  and the main brake cylinder  14  via a push rod  15  which is pivotably connected to the pedal arm  11  via a second pivotal joint  16 . The second pivotal joint  16  is for example formed by a swivel head  17  mounted to one end of the push rod  15 , which is held in a spherical cup  18  provided in said pedal arm  11 . The swivel head  17  forms the proximal end of the push rod  15 . In an alternative embodiment a pull rod  15  may be employed if the positions of the first and second swivel joints  12 ,  16  are exchanged. 
         [0027]    The pedal arrangement  10  comprises a release arrangement  19  with a pyrotechnical actuator  20  which is activatable in response to a corresponding activation signal provided for example from a vehicle impact sensor. In the preferred embodiment shown in  FIGS. 1A to 1C  the pyrotechnical activator  20  is connected to the pedal arm  11  and acts on the proximal end  17  of the push rod  15  via a drive means  21 . The proximal end  17  of push rod  15  is movably guided in the pedal arm  11  for a translational movement essentially along the pedal arm  11 . 
         [0028]      FIG. 1A  shows the pedal arrangement  10  in a normal operation state. 
         [0029]    Upon activation in particular in response to a vehicle impact signal, the pyrotechnical activator  20  drives the drive means  21  downwards along the pedal arm  11 . The drive means  21  forces the proximal end of the push rod  15  downwards to a position where the push rod  15  reaches an aperture  23  provided in the pedal arm  11  at the front side thereof. The diameter of the aperture  23  is larger than the diameter of the swivel head  17  such that the push rod  15  can penetrate through the aperture  23  to the front side of the pedal arm  11 , see  FIG. 1C . In other words, the pedal arm  11  is released from the push rod  15  and can freely swing away from the driver, thus reducing the injury risk of the driver in the foot region. The release means  19  and the aperture  23  are preferably arranged above or behind a cover  24  such that there is no injury risk to the driver by the released push rod  15 . 
         [0030]    In the embodiment shown in  FIGS. 2A to 2C  the pyrotechnical activator  20  does not act on the push rod  15  but on a slide member  25  movably guided in the pedal arm  11  for a translational movement essentially along the pedal arm  11 . In the normal operation state shown in  FIG. 2A  the slide member  25  blocks the aperture  23 . Upon activation the pyrotechnical activator  20  causes the sliding member  25  to move essentially along the pedal arm  11  in order to uncover the aperture  23 , see  FIG. 2B , allowing the push rod  15  to penetrate through the aperture  23  as shown in  FIG. 2C . 
         [0031]      FIGS. 3A to 3C  and  4 A to  4 C show a further embodiment where the cup  18  for the swivel head  17  is formed by two cup forming members  26 ,  27  each of which for example forms a half of the cup  18 . In the present embodiment one cup-forming member  27  is fixedly mounted to the pedal arm  11  while the other cup-forming member  26  is movably guided in the pedal arm  11  for a translational movement essentially along the pedal arm  11 . Upon activation the pyrotechnical activator  20  causes the sliding member  27  to move essentially along the pedal arm  11 , thereby effectively splitting the cup  18 , in order to uncover the aperture  23  through the sliding member  27  and the pedal arm  11 , see  FIG. 3B , allowing the push rod  15  to penetrate through the aperture  23  as shown in  FIG. 3C . 
         [0032]    In an embodiment not shown in the Figures both cup-forming members  26 ,  27  may be movably guided along the pedal arm  11  in opposite directions, and the pyrotechnical activator  20  may be arranged to split the cup  18  by causing both cup-forming members to move along the pedal arm  11  in opposite directions in order to uncover the aperture  23 . 
         [0033]      FIGS. 5A to 5C  show a bendable, preferably metallic strip element  28  which is arranged between a front part  29  of the pedal arm  11  and a cup-forming member  30  forming the cup  18 . The release arrangement functions as described with reference to  FIGS. 1A to 1C . When the position in  FIG. 5B  corresponding to  FIG. 1B  is reached, the strip element  28  starts to deform while being pressed through the aperture  23  together with the push rod  15 , see  FIG. 5C . Due to the force limiting element  28  high accelerations of the released pedal arm  11  and an unwanted rebound of the pedal arm  11  can be avoided. 
         [0034]      FIGS. 6A and 6B  show another embodiment of a deformable force limiting element  31  in the form of a spring which in the released state shown in  FIG. 6B  acts between the part  29  of the pedal arm  11  and a collar  32  of the push rod  15 . The deformable element  31  may show essentially plastic behaviour reducing the risk of rebound of the pedal arm  11  after release. On the other hand, a deformable element  31  showing an elastic behaviour enables braking even after release of the pedal arm  11 . Therefore, it may be advantageous if the deformable element  31  shows a plastic-elastic behaviour which may be achieved by a combination of materials. 
         [0035]    FIGS.  7 Aa and  7 B show a preferred embodiment of a pyrotechnical activator  20  for a release arrangement  19  according to the invention. The activator  20  comprises a container  33  containing a pyrotechnical charge  34  having connectors  35  mounted at a first end and a piston  36  connected to a rod-shaped drive means  21  which is guided through an opening of the container  33  at the opposite end thereof. The container  33  furthermore comprises an indented member  37  forming an indented region  38  in which the piston  36  is received in an initial state. Upon ignition of the pyrotechnical charge  34  the indented member  37  expands axially towards the opposite end of the container  33  in order to move the piston  36  and the drive means  21 . The container  33  of the release arrangement  19  encapsulates pyrotechnical residues after deployment. The closed design associated with the indented member  37  provides shielding to the environment before and after deployment. The container  33  is preferably partly encapsulated by a sleeve which guides the expansion of the indented member  37 , restricts the piston  36  stroke, and stops the piston  36  from becoming a loose part. 
         [0036]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.