Abstract:
The presence of a child restraint seat on a vehicle seat is detected by movement of a pair of anchors from a first position to a second position when the child restraint seat is coupled with straps to the anchors. The anchors are pivotally or deflectively mounted on a cross bar which extends between side frame members within the back of the vehicle seat. Upon a sensor detecting the presence of the child restraint seat, an associated air bag is disabled so that the air bag will not be deployed against a child sitting in the child restraint seat if the car is in an accident. Upon removing the child restraint seat, the anchors return to the first position in which the sensor again enables the air bag for deployment because, in the absence of a child restraint seat, an occupant of the seat is more likely to be an adult than a child.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention is directed to child restraint seat detection devices. More particularly, the present invention is directed to child restraint seat detection devices which notify an air bag controller that a child restraint seat is present on a vehicle seat in order to deactivate or slow deployment of an air bag.  
       BACKGROUND OF THE INVENTION  
       [0002]     A child being carried by a child restraint seat can be subjected to relatively high impact forces upon deployment of an air bag against the child, whether the air bag is a front or side curtain air bag. Accordingly, it is suggested that children beneath a selected size and weight not be subjected to impact by air bags. In some vehicles, manual switches are provided to deactivate air bag deployment systems when a child restraint seat is occupied by a child. A driver or passenger can forget to operate the manual switch when a child is seated, or the air bag can be left in a deactivated mode when an adult is seated.  
         [0003]     This has led to arrangements for automatically deactivating air bags when the presence of a child rather than an adult in a vehicular seat is detected. Currently, these devices respond to the weight of a person occupying a passenger seat, whether that person is an adult or a child, rather than responding to the mere presence of a child restraint seat. It has been found that some weight based suppression systems that are installed in the seat cushion of the right front passenger seats have difficulty correctly classifying Lower Anchorage and Tether for Children (LATCH) child restraint seats that are attached to the lower anchorages of the right front passenger set. The reason for this difficulty is the inability of the suppression system to detect the amount of load being applied by the attached child restraint seat to the set cushion resulting in added weight measurement to the suppression system. This misclassification occurs when this added weight equals the amount of weight that an adult occupant would apply while seated in the right front passenger seat. It is not currently realized that the mere presence of a child restraint seat in almost all cases precludes occupancy of the passenger seat by an adult, who is less likely to experience ill effects from an air bag impact than an infant or small child. Accordingly, there is a need in systems, such as LATCH child restraint seat systems, for detection devices which recognize the mere presence of a child restraint seat and use that recognition to deactivate or alter deployment speeds of airbags.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention is directed to a device for detecting the presence of a child restraint seat when the child restraint seat is attached to a vehicle seat. The device comprises an anchor fixed with respect to the seat, the anchor having at least one coupler adapted to couple with a complementary coupler on a child restraint seat to retain the child restraint seat on the vehicle seat. The anchor is movable with respect to the seat and is biased to a first position with respect to the seat indicative of an absence of a child restraint seat coupled to the anchor. A position sensor is attached to the anchor for detecting movement of the anchor to a second position with respect to the seat, indicating a child restraint seat is coupled to the anchor. The position sensor is adapted to transmit a signal to an air bag controller disabling deployment of the air bag when the anchor is moved to the second position.  
         [0005]     In another aspect of the invention, the second position is angularly off-set from the first position so that a tangential force on the anchor is required to move the anchor from the first position to the second position.  
         [0006]     In a first embodiment of the invention the anchor is biased to the first position by at least one spring.  
         [0007]     In one aspect of the first embodiment of the invention, the anchor is pivotally mounted with respect to the seat and rotates from the first position to the second position against the bias of the spring.  
         [0008]     In accordance with a second embodiment of the invention, the anchor is resilient and is urged by its resilience to the first position, deflecting from the first position to the second position upon securing the child restraint seat thereto.  
         [0009]     In still another embodiment of the invention, the seat includes a seat back frame to which the anchor is attached.  
         [0010]     In still another embodiment of the invention, the anchor comprises an anchor bar extending along a cross bar disposed in the seat back frame, the anchor having two couplers at spaced locations thereon, each of which couplers latches with a complementary coupler on the child restraint seat that is attached to an adjustable strap. When under tension the adjustable straps apply force to the couplers moving the anchor from the first position to the second position, thereby signaling an air bag controller that a child restraint seat is present and that the air bag should not be deployed.  
         [0011]     The present invention is further directed to a device for detecting the presence of a child restraint seat when the child restraint seat is attached to a vehicle seat having a seat back frame, the seat back frame including a pair of horizontally spaced side frame members. The device comprises a cross bar having first and second ends, the first and second ends being fixed to the pair of side frame members. An anchor comprising an anchorage bar is mounted on the cross bar, the anchorage bar having first and second couplers thereon for latching with corresponding couplers on the child restraint seat to retain the child restraint seat on the vehicle seat. The anchorage bar is biased to the first position, but movable with respect to the cross bar from a first position indicative of the absence of a child restraint seat to a second position, indicative of the presence of a child restraint seat. A position sensor is attached to the anchorage bar for detecting movement of the anchorage bar from the first position to the second position. The position sensor is adapted to transmit a signal to an air bag controller when moved to the second position indicating the presence of a child restraint seat on the vehicle seat, wherein the air bag controller either disables the air bag or adjusts a weight measurement to compensate for weight imposed by the attached child restraint seat.  
         [0012]     In an aspect of the aforedescribed invention, the anchorage bar is pivoted on the cross bar and is biased to the first position by at least one spring.  
         [0013]     In still a further aspect of the aforedescribed invention, the anchorage bar is resilient and fixed to the cross bar for deflection from the first position to the second position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Various other features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:  
         [0015]      FIG. 1  is a side view showing a forward facing child restraint seat being mounted on a vehicle set in accordance with the principles of the present invention;  
         [0016]      FIG. 2  is a side view showing a rearward facing child restraint seat being mounted on a vehicle seat in accordance with the principles of the present invention;  
         [0017]      FIG. 3  is a perspective view of a front vehicle seat, modified in accordance with the principles of the present invention, to anchor the child restraint seats of  FIGS. 1 and 2 ;  
         [0018]      FIG. 4  is a front perspective view of a device for securing a child restraint seat to the vehicle seat of  FIGS. 1-3 ;  
         [0019]      FIG. 5  is a side view showing an anchorage bar of  FIG. 7  or  FIG. 8  in a first position, and  
         [0020]      FIG. 6  is a side view showing the anchorage bar of  FIG. 7  or  FIG. 8   a  second position.  
         [0021]      FIG. 7  is a back perspective view of a first embodiment of the device of  FIG. 4 ;  
         [0022]      FIG. 8  is a back perspective view of a second embodiment of the device of  FIG. 4 . 
     
    
     DETAILED DESCRIPTION  
       [0023]     Referring now to  FIGS. 1 and 2  there is shown a front vehicle seat  10  having a seat portion  12  and a back portion  14 . The back portion  14  is cantilevered to the seat portion  12  and the seat portion is anchored to the floor  16  of the vehicle. The back portion  14  has a rigid frame  20  therein which is covered by padding and upholstery  22 . Attached to the frame  20  is an anchorage  23  comprising cross bar  24  which has child restraint seat anchors  25  and  26  including anchor loops  27  and  28  attached thereto.  
         [0024]     A child restraint seat  30  has a pair of straps  31  and  32  thereon with hooked couplers  34  and  35 . The straps  31  and  32  have fittings  36  and  37  which allow the straps to be adjusted in length between the child restraint seat  30  and the hooked couplers  34  and  35  by pulling on ends  39  and  40  of the straps. Thus, when the child restraint seat  30  is attached by the hooked couplers  31  and  32  to the anchor loops  27  and  28  of the anchors  25  and  26 , and the ends  39  and  40  of the straps  31  and  32  are pulled, tension is applied to the straps and thus to the anchors  25  and  26 .  
         [0025]     In the illustrated embodiment, the vehicle seat  10  is a right front passenger seat for American road vehicles or a left front passenger seat for vehicles such as UK road vehicles. The illustrated vehicle seat  10  is an existing seat configuration, however the principles of the present invention may apply to other seat configurations. Only if a vehicle&#39;s air bag is disabled should one consider mounting a child restraint seat  30  on the vehicle seat  10  facing rearwardly as shown in  FIG. 2 . The arrangement according to the present invention increases the likelihood that air bags are in fact disabled. If the child restraint seat  30  is facing forward, a tether  43  with a hook  45  is hooked into either an anchor on the back  14  of the vehicle seat  10  or fixed to the vehicle frame supporting the floor  16  at a location behind the seat anchors  25  and  26 .  
         [0026]     Referring now to  FIG. 3 , it is seen that the seat back frame  20  comprises vertical frame members  41  and  42 , which are laterally spaced from one anther by a distance  44 . In accordance with one embodiment of the present invention, the cross bar  24  of the anchorage  23  extends between the frame members  41  and  42  adjacent to the lower ends thereof and is welded at opposite ends  47  and  48  thereof to the frame members  41  and  42 . The anchors  25  and  26  to which the hooked couplers  34  and  35  are attached via the anchor loops  27  and  28  are mounted on the cross bar  24  adjacent the opposite ends  47  and  48  thereof. In accordance with the present invention, as the straps  31  and  32  are tightened by pulling on the ends  39  and  40  of the straps, the anchors  25  and  26  move from a first position to a second position. If the straps  31  and  32  are of an effective length to begin with that applies tension to the anchors  25  and  26  when the hooked couplers  34  and  35  are attached, the straps need not be shortened.  
         [0027]     The resulting movement of the anchors  25  and  26  is detected by a position sensor  52  which is operatively associated with the anchors. The position sensor  52  is connected by line  53  to an air bag controller circuit  56  that is switched to a disabling mode (or weight adjusting mode) which prevents the airbag or airbags  58  associated with the vehicle seat  10  from deploying either at all, or at full speed. The air bag  58  is a passenger seat air bag arrangement which may include a side curtain air bag. Upon securing the child restraint seat  30  to the vehicle seat  10 , an automatic decision not to deploy is thus made independent of a passenger&#39;s weight. On the other hand, if the air bag controller circuit  56  decreases deployment speed for seat occupants of reduced weight, such as small children, then the signal from the load sensor  52  is used to adjust the weight measurement to compensate for the weight imposed by the attached child restraint seat  30 .  
         [0028]     Referring now to  FIG. 4 , there is shown a front perspective view of the cross bar  24  in isolation to which the anchor  25  is fixed by welds  61  and  62  and the anchor  26  is fixed by welds  63  and  64 . The anchors  26  and  28  are connected to a rear bar  66  by arms  68  and  70 , respectively. The rear bar  66  allows either pivoting or deflection of both the anchors  25  and  26  with respect to the cross bar  24  when the anchors  25  and  26  are tensioned by attaching the hooked couplings  34  and  35  ( FIGS. 1 and 2 ) to the anchor loops  27  and  28 . Since the child or infant restraining seat  30  is disposed above the anchors  25  and  26  (see  FIGS. 1 and 2 ) torque with a tangential component is applied to the arms  68  and  70  to pivot the anchors  25  and  26  and the reaction plate  60  upwardly.  
         [0029]     In accordance with an illustrated embodiment of the invention, a permanent magnet  74  is fixed to the reaction plate  60  while the position sensor  52  attached to the cross bar  24  includes a reed switch  75 . As the permanent magnet  74  rises upon the anchors  25  and  26  pivoting with respect to the cross bar  24 , the reeds within the reed switch  75  deflect into contact with one another generating an electrical signal. This electrical signal is applied over the line  53  ( FIG. 3 ) to the air bag controller circuit  56  to disable the air bag  58  associated with the vehicle seat  10 , so as to prevent the air bag from deploying or to slow speed of deployment. The reed switch  75  remains closed as long as the permanent magnet  74  is lifted into proximity with the reed switch. Upon the hooked couplers  34  and  35  being disconnected from the anchors  25  and  26 , the permanent magnet  74  is lowered with respect to the reed switch  75  to move out of proximity with the reeds thereby opening the reed switch. This results in a signal being transmitted over the line  53  to the air bag controller circuit  56 , again enabling deployment of the air bag or airbags  58  upon the occurrence of an accident.  
         [0030]     Referring now to  FIG. 5  where a side view of the anchor bar  24  is shown, it is seen that the anchor plate  60  is in a first position wherein the anchor plate abuts lower surfaces  76  and  78  (see also  FIG. 4 ) of the cross bar  24  so that the permanent magnet  74  on the anchor plate  60  is out of alignment with the reeds of the reed switch  75 .  
         [0031]     Referring now to  FIG. 6 , it is seen that the arms  68  and  70  have been rotated with their ends lifted so that the upper stop surfaces  80  and  82  (see also  FIG. 4 ) of the cross bar  24  are engaged by the arms. Rotating the arms  68  and  70  the permanent magnet  74  into proximity with the reed switch  75  closes the switch  56  so as to disable or reduce the speed of air bag deployment. As is seen in  FIG. 6 , the tension applied by the hooked couplers  34  and  35  has a tangential component which causes the anchors  25  and  26  to rotate from the first position of  FIG. 5  to the second position of  FIG. 6 .  
         [0032]     Referring now to  FIG. 7 , there is shown a first embodiment for mounting the anchors  25  and  26  on the cross bar  24  of the anchorage  23  which extends between the side frame members  41  and  42  of the seat back  14  (see  FIGS. 1 and 2 ). The arrangement of  FIG. 7  is one of two preferred embodiments for mounting the anchors  25  and  26 . In the arrangement of  FIG. 7 , a slot  85  in the cross bar  24  has three bearings  86 ,  87  and  88  disposed therein that allow the rear bar  66  to rotate with respect to the cross bar  24 . Coil springs  89  and  90  each have one end attached to the cross bar  24  and the other end attached to the rear bar  66 . The coil springs  89  and  90  bias the legs  70  and  68  down to the first position of  FIG. 5 . Upon applying a force to the anchors  25  and  26  by connecting the hooked couplers  34  and  35  thereto and pulling the straps  39  and  40  taught, the arms  68  and  70  have a tangential force component applied thereto which causes the rear bar  66  to rotate within the bearings  86 - 88  against the bias of the springs  89  and  90 . This lifts the arms  68  and  70  to the  FIG. 6  position, wherein the arms abut upper top surfaces  80  and  82  of the cross bar  24  so that the permanent magnet  74  closes the reeds in the reed switch  75  ( FIG. 3 ). Upon releasing the hooked couplers  34  and  35  (see  FIG. 3 ), the springs  89  and  90  return the anchors  25  and  26  to the  FIG. 5  position in which the magnetic reed switch  75  is open.  
         [0033]     Referring now to  FIG. 8 , there is shown a second preferred embodiment of the invention wherein rear bar  66 ′ is welded within the slot  85 ′ at three weld areas  93 ,  94  and  95  so that the bar  66  is rigidly retained to the cross bar  24 . In the embodiment of  FIG. 8 , the legs  68  and  70  flex so as to deflect upwardly upon application of a tangential lifting force by the hooked couplers  34  and  35  applied to the anchors  26  and  28 . The anchors  26  and  28  deflect upwardly until the legs  68  and  70  abut the upper surfaces  80  and  82  of cross bar  24 , thus lifting the permanent magnet  74  into alignment with the reeds of the reed switch  75  (see  FIGS. 3 and 5 ). Upon releasing the hooked couplers  34  and  35 , the anchors  25  and  26  return to the position of  FIG. 5  from which they had been deflected when the child restraint seat  30  was fastened to the vehicle seat  10 .  
         [0034]     While the anchors  26  and  28  are shown mounted on the cross bar  24  in accordance with preferred embodiments of the invention, the anchors in accordance with other embodiments of the invention are mounted directly to the side frames  41  and  42  of  FIG. 2  and are connected by structure such as the bar  66  so as to act in concert in order to activate the switch  52 .  
         [0035]     While a reed switch  75  is disclosed, the position switch  52  in other embodiments can be an electromechanical contact switch, a resistive switch, a magnetic switch other than a reed switch, a strain gauge switch, a capacitive switch, or any other type of suitable switch.  
         [0036]     From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention, and without departing form the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.