Abstract:
The invention relates to a vehicle seat ( 1 ) having an automatically displaceable lower leg support ( 3 ). The lower leg support can be displaced in an automatically driven fashion between a stowaway position and a position of use.  
     In order to obtain a compact design of the vehicle seat and a high degree of protection against impact operation, the lower leg support ( 3 ) has a sensor ( 6, 61, 62 ) which is connected to a control device ( 52 ) of the drive ( 5 ). The sensor ( 6 ) is designed to detect an obstacle.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a vehicle seat.  
       BACKGROUND INFORMATION  
       [0002]     German Published Utility Model No. 92 00 777.5 describes a bus seat with a footrest. The footrest is coupled to the seat cushion of the bus seat via a parallelogram linkage. A pneumatic spring interacts with the parallelogram linkage in order to fold the footrest from a stowaway position arranged underneath the seat cushion into a position of use.  
         [0003]     German Published Patent Application No. 39 10 778 describes a control device for the backrest of a seat. The control device controls an actuator device which adjusts the inclination of the backrest of a seat. This control device detects an obstacle as the backrest of the seat inclines, it stops the inclination movement of the backrest of the seat.  
       SUMMARY  
       [0004]     An example embodiment of the present invention may provide a vehicle seat with an adjustable lower leg support which may have a compact design, may have a comfortable sitting position and may be easy and safe to operate. The vehicle seat may have a high degree of protection against incorrect operation.  
         [0005]     The lower leg support of the vehicle seat has an automatic drive. A control device with a sensor is connected to the drive in order to control the lower leg support. The sensor is designed to detect an obstacle. As a result, trapping and/or damage and/or the risk of injury as the lower leg support is automatically adjusted, or when incorrect operation is carried out, is at least partially reduced or entirely prevented.  
         [0006]     The drive is designed to adjust the lower leg support automatically, e.g., in an infinitely variable fashion, e.g., in order to displace the lower leg support from a space-saving stowaway position into a position of use and/or from a position of use into the stowaway position. It is also possible to adjust and/or set the sitting position as desired using the drive. The stowaway position is arranged closely against the seat so the vehicle seat may take up as little overall space as possible. The control device may be designed such that it detects the stowaway position of the lower leg support as a zero position, which serves as the reference position for determining the travel of the lower leg support. In the position of use, the lower leg support is pivoted into the foot well and forms a comfortable rest and/or support for the lower legs and/or the feet of the sitting person. The control device calculates the position of the lower leg support in the position of use by the pivoting angle and/or the displacement travel.  
         [0007]     In an example embodiment, the lower leg support is pivoted by the drive about a pivot axis which extends transversely with respect to the vehicle seat. In addition, the length of the lower leg support may be varied, e.g., the area on which the lower legs rest may be increased by lengthening the lower leg support. During this adjustment process, the lower leg support may strike an obstacle, for example, a piece of luggage or the feet of a sitting person. In order to prevent the obstacle becoming trapped, and/or the lower leg support and/or the obstacle being damaged, the sensor is arranged at the free end of the lower leg support.  
         [0008]     The sensor may be arranged as a proximity sensor, e.g., an inductive or capacitive proximity sensor and/or as a pressure sensor, e.g., as a piezoelement and/or switch panel. When an obstacle is struck and/or detected, the sensor transmits a signal to the control device.  
         [0009]     In an example embodiment, provision is made for the control device to stop the drive if the sensor detects an obstacle. However, it is also possible for the control device to stop the drive and/or at least partially reverse it in order to prevent the lower leg support and/or the obstacle from being trapped and/or damaged.  
         [0010]     The sensor may also be arranged to determine the maximum possible displacement travel of the lower leg support. For this purpose, by actuating the drive, the control device moves the lower leg support out until it arrives at a limit position, i.e., abutting against installations in the vehicle or seats. The sensor detects this limit position so that the control device may detect and/or store the maximum possible adjustment travel of the lower leg support. As a result, e.g., tolerances between the arrangements in the vehicle or installations in the vehicle and the displacement travel and/or the dimensions of the lower leg support may be sensed and compensated for. The sensor detects the set position with the largest possible displacement travel and thus limits the displacement travel in this limit position.  
         [0011]     It is possible to use the vehicle seat in passenger cars, buses and watercraft or rail vehicles, etc. The vehicle seat may also be provided as a comfortable passenger seat in aircraft.  
         [0012]     According to an example embodiment of the present invention, a vehicle seat includes: an adjustable lower leg support; a drive configured to automatically adjust the lower leg support between a stowaway position and a position of use, and a control device configured to control the drive. The control device includes a sensor arranged on the lower leg support configured to detect an obstacle.  
         [0013]     The sensor may be configured as at least one of (a) a proximity sensor and (b) a pressure sensor.  
         [0014]     The drive may be configured to adjust at least one of (a) a length and (b) an inclination of the lower leg support.  
         [0015]     The drive may be configured as one of (a) an electrical drive and (b) a pneumatic drive.  
         [0016]     The lower leg support may include an enclosed lower leg support surface.  
         [0017]     The drive may be configured to at least one of (a) increase and (b) decrease the lower leg support surface.  
         [0018]     The lower leg support may include a freely displaceable end and an end pivotably mounted on one of (a) a seat cushion and (b) a seat frame, and the sensor may be arranged at the freely displaceable end of the lower leg support.  
         [0019]     The sensor may include two detection regions.  
         [0020]     The sensor may include a first detection region arranged on a rear of the lower leg support and a second detection region arranged on an end side of the lower leg support.  
         [0021]     One of (a) the first detection region and (b) the second detection region may be configured to detect an obstacle when the lower leg support pivots.  
         [0022]     One of (a) the first detection region and (b) the second detection region may be configured to detect an obstacle when the lower leg support is extended.  
         [0023]     The sensor may include a bar arranged to cover and connect the first detection region and the second detection region, and the bar may be configured to distribute pressure, that occurs when an obstacle is struck, between the first sensor region and the second sensor region.  
         [0024]     The control device may be configured to at least one of (a) stop and (b) reverse the drive in accordance with detection of an obstacle.  
         [0025]     According to an example embodiment of the present invention, a vehicle seat includes adjustable lower leg support means, drive means for automatically adjusting the lower leg support means between a stowaway position and a position of use, and control means for controlling the drive. The control means includes sensing means arranged on the lower leg support and for detecting an obstacle.  
         [0026]     Further features and example embodiments of the present invention are described below with reference to the appended Figures. The features and feature combinations which are mentioned above and described below may be used not only in the respectively stated combination but also in other combinations or alone. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0027]      FIG. 1  is a view of the vehicle seat with the lower leg support in a position of use.  
         [0028]      FIG. 2  is a cross-sectional view of the lower leg support in a stowaway position.  
         [0029]      FIG. 3  is a schematic view of the arrangement of the lower leg support.  
         [0030]      FIG. 4  is a cross-sectional view of the sensor. 
     
    
     DETAILED DESCRIPTION  
       [0031]      FIG. 1  illustrates a vehicle seat  1 . It has a backrest  11  with headrest  12  and a seat cushion  2  with lower leg support  3 . The vehicle seat  1  is displaceably mounted by rails  14  in a vehicle, for example, in the rear of a passenger car. A seatbelt mount  13  for a three-point belt is integrated into the backrest  11 . The backrest  11  and the seat cushion  2  each have an upholstered element with a covering material, for example, leather. The upholstered element  21  upholsters the seat cushion  2  and the lower leg support  3  and is of continuous design. It forms, on its upper side, a coherent, upholstered sitting surface which extends from the seat cushion  2  as far as the lower leg support  3 .  
         [0032]     The lower leg support  3  is extended forward in the position of rest or position of use which is illustrated in  FIG. 1 . It has been pivoted up in the forward direction and extended in order to enlarge its resting surface for the lower legs. The lower leg support  3  has a three-component telescopic component with an upper telescopic element  32 , a central telescopic element  33  and a lower telescopic element  34 . In order to vary the length of the lower leg support  3 , the telescopic elements  32 ,  33  and  34  may be adjusted in a telescopic fashion by an electric drive  5 . A footrest  4  is arranged at the lower end of the lower leg support  3 . It is connected to the lower telescopic element  34  and has a footplate  41  which is mounted on a crossmember  42  and which is folded out into the position of use and provides a comfortable support for the feet. The footplate  41  may be pivoted about an axis of rotation which extends transversely with respect to the lower leg support  3 , and in the position of use it is approximately perpendicular to the lower leg support  3 . One end of the lower leg support  3  is connected to the seat cushion  2 . The inclination of the lower leg support  3  in relation to the seat cushion  2  may be set by an inclination adjuster  35  with an electric drive motor. The other end of the lower leg support is freely displaceable and supports the footrest  4 . A sensor  6  for detecting obstacles in the displacement path of the lower leg support  3  is arranged at the free end.  
         [0033]     The vehicle seat  1  has both the position of rest or lying position illustrated in  FIG. 1  and further sitting positions, e.g., also an upright sitting position with retracted lower leg support  3  and a folded-in footrest  4 .  
         [0034]     The stowaway position with retracted lower leg support  3  and folded-in footrest  4  is illustrated in  FIG. 2 . The telescopic elements  32 ,  33  and  34  of the lower leg support  3  are pushed one into the other and are arranged pointing approximately vertically downwardly at the front end of the seat cushion  2 . An inclination adjuster  35 , which connects the lower leg support  3  to the seat cushion  2 , is arranged on the upper telescopic element  32 . The inclination adjuster  35  has an electric motor for adjusting the inclination of the lower leg support  3 .  
         [0035]     The footplate  41  is arranged in parallel with the lower leg support  3  and forms, together with the seat upholstered element  21 , a planar front surface which closes off the vehicle seat from the front. The rear of the footplate  41  is flush with the upper side of the seat upholstered element  21  so that the vehicle seat does not have any protruding edges and/or the footplate  41  may not be inadvertently folded forward. In the stowaway position, the lower leg support  3  and the footrest  4  are arranged resting against the front region of the seat cushion  2 . This stowaway position may save space and may not adversely affect the amount of foot space available in the vehicle.  
         [0036]     The sensor  6  is arranged at the lower end of the lower leg support  3  and has two sensor surfaces  61 ,  62 . The first sensor surface is arranged on the end side of the lower leg support  3  and is arranged to detect obstacles which are in its displacement path when the lower leg support  3  extends in a linear fashion. The second sensor surface  62  is arranged at the rear of the lower leg support  3 , i.e., on the side facing away from the lower leg support surface. It is arranged to detect obstacles which are in the displacement path when the lower leg support  3  is pivoted.  
         [0037]      FIG. 3  illustrates the schematic design of lower leg support  3  with drive  5 . The drive  5  is arranged as a spindle drive and has an electric drive motor  51  which drives a first spindle drive  56  and a second spindle drive  57 . The drive  5  is connected via a bridge to the central telescopic element  33 . The first spindle drive  56  engages between the central telescopic element  33  and the upper telescopic element  32 , and the second spindle drive  57  engages between the central telescopic element  33  and the lower telescopic element  34 . The upper telescopic element  32  and the lower telescopic element  34  are moved synchronously away from the central telescopic element  33  or toward the central telescopic element  33  via the spindle drive  56 ,  57 .  
         [0038]     The electric drive motor  51  drives the first spindle drive  56  and the second spindle drive  57  in opposite directions by a gear mechanism. As a result, the electric motor  51  drives the telescopic elements  32 ,  33 ,  34  such that, in one sense of rotation, the upper telescopic element  32  and the lower telescopic element  34  are driven away from the central telescopic element  33 , and in the opposite sense of rotation, the upper telescopic element  32  and the lower telescopic element  34  are driven toward the central telescopic element  33 .  
         [0039]     The drive motor  51  is connected to a control device  52 . The control device  52  controls the drive motor  51  and/or the inclination adjuster  35  and thus the movement sequence of the lower leg support  3 . The control device  51  is connected to the sensor  6  in order to detect obstacles, the sensor  6  being arranged at the lower end of the lower leg support  3 . The control device  52  is connected via cables to the sensor  6  and in addition to the drive motor  51  and the inclination adjuster  35 . In addition, the control device  52  has a power feed line. A cable guide  53  which is connected to the central telescopic element  33  prevents the cables becoming entangled and/or damaged when the lower leg support  3  moves. The cable guide  53  has a spring-loaded cable drum which automatically retracts or unrolls the guided cables. The cable guide  53  therefore takes up the cable slack and keeps the cables taut so that the cables are prevented from becoming entangled and/or flapping around.  
         [0040]     If the sensor  6  detects an obstacle, it transmits a signal to the control device  62 . The latter then stops the movement of the lower leg support  3  and moves it back a certain amount in order to prevent the obstacle from becoming trapped and/or being damaged.  
         [0041]      FIG. 4  illustrates the sensor  6 . It is arranged on the crossmember  42  of the lower telescopic element  34 . A first sensor surface  61  is arranged on the end surface and a second sensor surface  62  is arranged at the rear of the crossmember  42 . The sensor surfaces  61 ,  62  extend over a large part of the width of the lower leg support  3  and are arranged as pressure-sensitive switch panels.  
         [0042]     The sensor  6  has an electrically conductive contact film  65  which is connected in a planar fashion to the crossmember  42  via an insulator  64 . An electrically conductive connecting strip  66  is arranged over foam inlays  67  which are arranged as spacing elements and are at a distance from the contact strip  65 . If pressure is exerted on the connecting strip  66 , the foam inlay  67  is pushed over and the connecting strip  66  moves into electrically conductive contact with the contact strip  65 .  
         [0043]     An elastic rubber strip  63  covers the first switching surface  61  and the second switching surface  62 . The rubber strip  63  is clipped to the crossmember  42  and secures the sensor  6  so that it rests directly on the crossmember  42 . The rubber strip is connected to the sensor  6  so that, in order to replace the sensor  6 , only the rubber strip  63  with sensor  6  has to be replaced.  
         [0044]     The elasticity of the rubber strip  63  may be dimensioned such that, when there is contact with an obstacle, it distributes the pressure which occurs between the first sensor surface  61  and the second sensor surface  62 . As a result, the obstacle may be reliably detected even if the obstacle does not directly strike the first sensor surface  61  or the second sensor surface  62 .  
         [0045]     In the stowaway position, the sensor  6  abuts against the vehicle seat  1 . As a result, the sensor  6  detects the home position of the lower leg support  3 . The home position thus serves as a reference position for the control device  52 , from which position it determines the position of the lower leg support over the displacement travel. In order to compensate for tolerances, the control device may determine the limit position of the lower leg support  3  by moving out the lower leg support to a maximum extent until the lower leg support moves into contact with installations in the vehicle, and the sensor  6  signals the limit position. The sensor  6  detects the maximum possible displacement position and thus limits the maximum possible displacement travel of the lower leg support  3 .